The Dangers Of Diving Medicine

http://web.utah.edu/umed/students/clubs/international/presentations/dangers.html
Introduction to Dive Medicine

DIVING MEDICINE
Diving Medicine is a growing medical speciality that focuses on the study, diagnosis and treatment of illnesses related to changes in pressure and the undersea environment. This area is rapidly expanding its knowledge base as the popularity of diving and undersea exploration continues to explode. A primary focus of diving medicine is to assess individual "Diving Fitness". As more and more people take to the water, there is an increased need to safely prepare or assess ability to dive among patients with various disease states. Particularly, dive physicians must understand how various ENT, Eye, Heart, Pulmonary,
Gastrointestinal, Bone and Joint, Hematologic, Endocrine and Metabolic disease states affect the ability to dive. In addition, dive physicians can offer recommendations for people about flying and altitude, physchology and drugs, dental work, women specific concerns, hazardous marine life, long term effects of diving and specific treatment modalities if an accident occurs.
The primary accidents occuring in diving typically deal with effect pressure has on the various gases in your body. Most dive physicians treat patients for problems with equalizing pressure in their ears, sinus difficulties and of course barotrauma due to rapid ascension - "the bends". While these areas of dive medicine are perhaps most critical to understand in terms of patient care and treatment. I have chosen to speak on the more exotic, but rare, injuries from interactions with marine life.

OVERVIEW OF MARINE HAZARDS
There are a number of hazardous creatures in the sea. Many can cause serious harm to unaware or inattentive divers. Some may even cause death, although this often depends on the amount of venom used, individual reactions, nature of injury and location of accidents (deep water victims often drown). There are four major types of injury patterns from marine life. This presentation will Some basic first aid tips are given, although by far the best policy is not to meddle with these creatures.

CONTACT IRRITANTS

Sea Anenomes and Sea Cucumbers
While most sea anemones are relatively harmless to humans a few do contain strong toxic substances producing quite severe effects. One of these is the stinging anemone(Actinodendron plumosum), a blue-grey to light brown animal which can look somewhat like a fir tree.
Found under boulders and coral, red bristle worms have numerous fine needle-like bristles which break off when they have become embedded in the skin, causing severe irritation.
Although sea cucumbers are one of the safest animals on the reef to touch, the numerous white Cuvierian tubules, which some eject when irritated, contain a toxin which can cause blindness if it comes into contact with the eyes. This toxin may also be present on the skin so you should wash your hands after handling these creatures.

STINGING CORALS
Although known widely as stinging or fire corals, these organisms are, in fact, colonial animals (Millepora sp) more closely related to hydroids. Having a hard coral-like skeleton, they vary in form from large upright sheets and blades to branching, finger-like 'antlers ' with a yellow-green to brown colour. Effects and treatment are similar to hydroid stings.

CROWN-OF-THORNS STARFISH
The sharp spines of this creature are covered with a thin venomous skin which, if introduced into any wound can cause nausea, vomiting and swelling. Spines may also break off and remain embedded.

HYDROIDS
Looking like feathery plants, and sometimes referred to as fireweed, hydroids are actually colonies of animals equipped with strong stinging cells (nematocysts) used to capture prey and for defence. Some species can give quite severe stings causing inflammation, swelling and pain lasting up to a week. Effects may sometimes be more severe.
Divers are particularly prone to brushing against hydroids. Two species to avoid are this white, fine feathery one and the denser yellow/brown type. They can be found in fairly shallow reef areas and on structures such as wharfs.
BOXES OF DEATH - BOX JELLYFISH
Recognized as one of the greatest marine hazards, box jellyfish(Chironex fleckeri) kill more people than sharks, crocodiles and stonefish combined.
Each year, in late summer, the adult box jellyfish spawn at river mouths before dying. The fertilised eggs become tiny polyps which attach themselves to rocks in estuaries. In spring these polyps develop into little swimming jellyfish which migrate down rivers, especially with rains, to feed on shrimp. Unfortunately, they frequent beaches which humans also find attractive. The animal does not actively hunt, relying on food to bump into its tentacles. A struggling shrimp might tear a delicate jellyfish, so it needs to be killed instantly, on contact, with a very strong poison.
Tentacles, up to 60 in number and reaching 5m in length, are arranged in four groups at the corners of a box-shaped bell which can be as large as a basketball. The tentacles are armed with up to 5 000 million stinging cells known as nematocysts. These are triggered into action when stimulated by certain chemicals found on the surface of fish, shellfish and humans. Contact with just 3m of tentacles can kill an adult.
Recent studies have shown that the box jellyfish is able to see through four eyes, one at the centre of each side of the bell. How it processes this information without a brain is still a mystery but the animal is able to avoid even quite small objects. They probably try to avoid humans in the water, if given the chance; stings usually occur when people blunder into them. (They are almost invisible in the water.) It is certainly in the interest of the jellyfish to avoid turtles which eat them, apparently unaffected by the stings.
Another box jellyfish, Chiropsalmus quadrigatus, is generally less common than Chironex fleckeri, although it may outnumber them on Cairns to Port Douglas beaches. It is smaller, with slimmer tentacles, but the two are difficult to tell apart. There are about 20 species, worldwide, in the Cubozoa, or box jellyfish, family, Chironex fleckeri is the most lethal member.

IRUKANDJIS
Although it is more numerous in summer months, the irukandji (Corukia barnesi) can be found all year round and inhabits all waters. A member of the box family, it has one tentacle at each corner of its bell. It is tiny - only 2cm across the bell - but nonetheless packs a massive punch. Both bell and tentacles have stinging cells.
The actual sting is minor, but 20-30 minutes later the victim begins to experience agony which lasts for hours. Although not blamed for deaths its tendency to cause raised blood pressure can be dangerous for vulnerable victims. Ignoring the initial sting may also lead to some people suffering severe symptoms in deep water or while driving.

SEA URCHINS
It is just common sense to avoid the sharp black spines of the black sea urchin. They can penetrate deeply into the flesh and break off causing long-lasting inflammation if not removed – often surgically. There is doubt as to whether venom is also involved.
A less common but much more dangerous urchin is the flower urchin. Instead of long spines it appears to be covered with numerous flowers which are in fact little venomous pincers (pedicillariae) capable of causing paralysis and even death. It has killed several people in Japan.

INGESTED TOXINS

Shell Fish
This derives from dinoflagellates contaminating shellfish (clams, scallops, oysters, etc.). The toxin, saxotoxin, is water soluble, heat and base stabile, and is therefore not affected by steaming or cooking. It inhibits sodium channels of excitable membranes, blocking propagation of nerve and muscle action potentials.
Symptoms: These usually occur within 30 minutes, and include parasthesias of the lips, tongue, gums and face. This process proceeds to the trunk and may progress to paralysis and respiratory arrest. The gastrointestinal form may appear hours or days after ingestion with nausea, vomiting, diarrhea and abdominal pain.
Treatment: No specific treatment. Stop eating if oral sensations are perceived. Empty stomach if systemic symptoms are noted, using emetic or lavage. Give respiratory support and monitoring if needed.

Scombroid
Occurs in tuna, mackerel, skipjack and other members of the family scombridae. Fish left at room temperature undergo bacterial breakdown of tissue histidine to histamine and saurine. Spoiled fish have a sharp, peppery taste.
Symptoms: Occur in the first hour, and a histamine-like intoxication is seen. There is headache, flushing, dizziness, palpitations and tachycardia. One may see hypotension, bronchospasm, urticaria and anaphylaxis. GI symptoms include nausea, vomiting, diarrhea, abdominal pain, thirst and dysphagia.
Treatment: Gastric lavage, respiratory and circulatory support. Antihistamines appear to be helpful.

Tetradoxin
Toad, or pufferfish, common in tidal creeks and coastal waters are well-known for their amusing habit of inflating their bodies with water or air to balloon-like proportions when provoked. Along with their relatives the porcupine fish, cowfish, boxfish, tobies and sunfish, their bodies contain the same toxin as the saliva of the blue-ringed octopus with the same, potentially fatal effects. Easily caught on fishing lines, they must never be eaten.
Derived from algae covered with bacteria Alteromonas sp.Being ingested by pufferfish The toxin concentrates in the liver and gonads. The toxin inhibits sodium transport, affects neuronal transmission in the CNS and periphery and also affects cardiac nerve conduction and contraction.
Symptoms: Entirely dose dependent-can have oral paresthesias, muscular fasciculations then a flaccid type of paralysis occurs. (curare-like).
Treatment: Gastric lavage and respiratory support, usually for 24 hours or more. Consider sedation because cognitive function intact. There will be spontaneous remission if the patient is otherwise supported.

Ciguatera
A form of food poisoning which occurs occasionally in certain coral reef fish. It originates in a tiny organism (dinoflagellate) attached to algae growing usually on dead coral. It is eaten by plant-eating fish and then accumulates in large predatory fish such as mackerel, coral trout and cod. The tasteless and odourless toxin is not destroyed by cooking or freezing.
All reef fish over 10kg should be treated with caution. Eat only a little and if symptoms develop discard the fish. Avoid internal organs of any reef fish. Symptoms, which begin 2-12 hours after fish are eaten, are varied and can include breathing difficulty requiring artificial respiration. If symptoms develop, induce vomiting.

INJECTED TOXINS

CONE SHELLS
Happily for humans, the animals which inhabit the beautiful cone shells are nocturnal. Hunters by nature, many carry a toxic concoction which is capable of killing humans; in fact, the venom from one geographer cone (Conus geographus)is capable (in theory of course,) of killing 700 people.
There are about 80 species of cone shells in Australia, mostly in tropical waters. Some feed on worms, some on molluscs (including other cone shells) and some on fish. It is the last two types which are most dangerous to humans. To stop a fish in its tracks a snail needs a formidably fast-acting venom.
It is thought that the cone detects its prey from chemicals in the water drawn through its siphon. Some visual sense may also be involved. The cone then extends its proboscis, a hollow feeding tube, on the end of which is a hollow, barbed tooth. Attached to a poison sac, this tooth is driven harpoon-style into the hapless victim, poison being injected through the tooth. The force of the harpoon has been known to penetrate a periwinkle shell. Each tooth is used only once. A supply of spares is kept in an internal tooth sac and moved into position as required. Held by the barbed tooth, the victim is quickly immobilised by the poison and then drawn into the expanded proboscis to be digested. A mollusc victim may be sucked from its shell (certain toxins may loosen its muscular attachment to the shell, making the task easier).
The best way to avoid stings is not to touch live cone shells. The extendable harpoon-wielding proboscis is capable of reaching most parts of the shell so it is not safe to grip the wide end. Thick shoes should be worn for reef walking and cones should never be put in pockets or sleeves. Sting symptoms progress from numbness to breathing failure.

BLUE-RINGED OCTOPUS
This potential killer is small, the northern (larger) species reaching only 20cm across spread tentacles. It is normally yellowish brown but when disturbed its blue rings become bright and obvious. It is not aggressive by nature but will bite when provoked.
The venom is contained in the saliva, which comes from two glands each as big as the animal 's brain. It has two components. One is probably most effective on crabs (its main prey) but relatively harmless to humans while the other, the same as that present in toad/puffer fish, probably serves as a defence against predatory fish. Humans, when bitten, usually do not feel the bite but soon notice a numbness around the mouth followed quickly by paralysis. Death can result from respiratory failure.
This octopus lives in shallow water, typically in sheltered rock pools and crevices, cans and bottles. Never put your hands where you cannot see them. The venom is not injected but enters the wound in saliva. Washing the bite may therefore remove venom from the surface.

STINGRAYS
Stingrays will defend themselves by lashing out with whip-like tails equipped with one or two spines. Because they are barbed they can cause serious gashes and in about two-thirds of species they are also venomous. The spines are capable of penetrating wetsuits and shoe leather and have been known to kill people unlucky enough to have been stabbed in the chest.
Those at risk are people wading, who often get injured on the leg, careless fishers and divers who may get lashed by a startled stingray as they swim above it. Prevention involves shuffling feet when wading. Wash wounds thoroughly with sea water and remove spines carefully.

VENOMOUS FISH
A number of other fish are equipped with similar venomous spines, although they are more mobile than stonefish and will prefer to get out of the way. These include members of the scorpionfish family, such as this popular aquarium fish known by many names such as lionfish, butterfly cod and firefish. (The freshwater bullrout is also in this family.)

Catfish, when interfered with, produce three barbed spines which stick out at right angles from the back and side fins. (It is not the whisker-like sense organs around their mouths which cause the damage.)
Stings from all these fish are painful and can lead to collapse and even death in exceptional circumstances. The venom in the spines remains active for days, so discarded spines and even refrigerated specimens should be treated with caution.

STONEFISH
The stonefish 's lifestyle makes this, the most venomous fish in the world, particularly dangerous to unwary humans. Lying on the seabed, looking exactly like an encrusted rock, it waits for small fish and shrimps to swim by and then, with lightning speed, opens its mouth and sucks them in. The whole ambush has been timed at just 0.015 seconds.
Vulnerable to bottom-feeding sharks and rays, it has developed a defence - a row of unlucky 13 venomous spines along its back. It is, in fact, the victim who injures him/herself. Each stonefish spine is encased in a sheath containing bulging venom glands. Downward pressure on the spine causes the sheath to be pushed back, the venom from the pressurised glands shooting forcefully up grooves on the surface of the spine into the deepest part of the wound. (It takes a few weeks for the glands to regenerate and recharge.)
Victims become frantic with pain which lasts for hours. Temporary paralysis, shock and even death may result. Stonefish may be found from exposed sand and mud in tidal inlets to depths of 40m. Prevention involves wearing thick-soled shoes and treading gently - spines may penetrate soles if a stonefish is jumped on. Also, take care when turning over 'rocks '.

SEA SNAKES
Sea snake venom is more toxic than that of land snakes, however these animals pose little risk. Most are shy and stay away from people, biting only when provoked, if at all. Even then they tend not to use their venom.
It is reserved for quickly immobilising prey, not for defence. In fact, about 65% of bites are 'blanks '. Nevertheless, the potential danger of a sea snake should not be underestimated and they should be treated with respect.
Sea snakes are air breathers probably descended from a family of Australian land snakes. They inhabit the tropical waters of the Indo-Pacific and are highly venomous. Thirty-two species have been identified in the waters about the Barrier Reef in Australia. They seem to congregate in certain areas in the region about the swain Reefs and the Keppel Islands, where the olive sea snake (Aipysurus laevis) is a familiar sight.
Sea snakes have specialized flattened tails for swimming and have valves over their nostrils which are closed underwater. They differ from eels in that they don 't have gill slits and have scales. Due to their need to breathe air, they are usually found in shallow water where they swim about the bottom feeding on fish, fish eggs and eels.
The yellow-bellied sea snake ( Pelamis platurus ) is planktonic, and is seen on occasions floating in massive groups. Fish that come up to shelter under these slicks provide food for the snakes. Occasionally these yellow-bellies get washed up on beaches after storms and pose a hazard to children.
Aggressive only during the mating season in the winter, the sea snake is very curious, and they become fascinated by elongated objects such as high pressure hoses. Advice here is to inflate your BC so as to lift away from the bottom and the snake. Provoked snakes can become very aggressive and persistent --requiring repeated kicks from the fins to ward them off.
Persistent myths about sea snakes include the mistaken idea that they can 't bite very effectively. The truth is that their short fangs (2.5-4.5mm) are adequate to penetrate the skin, and they can open their small mouths wide enough to bite a table top. It is said that even a small snake can bite a man 's thigh. Sea snakes can swallow a fish that is more than twice the diameter of their neck.
Most sea snake bites occur on trawlers, when the snakes are sometimes hauled in with the catch. Only a small proportion of bites are fatal to man, as the snake can control the amount of envenomation, a fact probably accounting for the large number of folk cures said to be 95% effective.
Intense pain is not obvious at the site of the sea snake bite; 30 minutes after the bite there is stiffness, muscle aches and spasm of the jaw followed by moderate to severe pain in the affected limb. There follows progressive CNS symptoms of blurred vision, drowsiness and finally respiratory paralysis. A specific antivenin is available; if not obtainable-the Australian tiger snake antivenin or even polyvalent snake antivenin can be used.

PREDATORS

Barracuda
The barracuda is any of about 20 species of predatory fishes of the family Sphyraenidae (order Perciformes). Barracudas are usually found in warm, tropical regions; some also in more temperate areas. They are swift and powerful, small scaled, slender in form, with two well-separated dorsal fins, a jutting lower jaw, and a large mouth with many sharp large teeth. Size varies from rather small to as large as 4-6 feet (1.2-1.8 meters) in the great barracuda (Sphyraena barracuda) of the Atlantic, Caribbean, and the Pacific.
Barracudas are primarily fish eaters of smaller fishes, such as mullets, anchovies, and grunts. They are good, fighting sporting fishes, and the smaller ones make good eating. In certain seas, however, lately increasingly they may become impregnated with a toxic substance that produces a form of poisoning known as ciguatera.
Barracudas are bold and inquisitive, and fearsome fishes, that may be/are dangerous to humans. The great barracuda is known to have been involved in attacks on swimmers. In Hawai 'i, they have been known to inhabit open waters and bay areas in the shadows, under floating objects. To avoid them, don 't wear shiny objects. They are attracted to shiny, reflective things that look like dinner. They cause harm with their sharp jagged teeth and strong tearing jaws; slashing and creating jagged tears in your skin. Should you or another be hurt by one get medical treatment.
Stop any bleeding and treat for shock by keeping yourself or the victim calm and warm.

Moray Eels
A number of divers have been bitten by moray eels, their sharp teeth designed to lock on to prey sometimes causing severe damage. These eels are not, by nature, aggressive towards people but can attack if provoked. Many attacks can be blamed on the foolish practice of fish feeding by hand. Accustomed to receiving handouts, some approach divers on sight and can bite a hand which they believe to be holding food.
For the same reason divers have also been approached aggressively by potato cod, wrasse, gropers and other fish expecting handouts of food. While some of these may not inflict injuries there is the additional threat that novice divers may be frightened into acting unwisely. The best prevention is to abide by the GBRMPA fish feeding guidelines which forbid the hand-feeding of fish.

Large Grouper
The Nassau grouper is common resident in the waters off the Gulf of Mexico and the Caribbean. Some divers have been "bitten" by over friendly Nassau groupers that are used to human interaction in popular dive feeding sites. During feedings groupers occasionally will take the entire fist and forearm of unsuspecting diver into their large mouths. Grouper have several sets of teeth, placed in the mouth to act as raspers or holding teeth. The fish gulps down its prey using these raspers to prevent the smaller fish from escaping. The teeth are not used to tear or slash, as with barracuda or sharks. One can imagine the problem with this when considering that some of these fish grow to be as large as 800 pounds. These bites primarily result in loss of skin from the back of the hand and fingers, often followed by a severe infection.

Salt Water Crocadile
This endangered reptile actually is a danger to underwater enthusiasts and a number of people are killed and injured each year. It 's hide has a very high commercial value because of its ease of skinning and because of this it is protected.
The saltwater crocodile is the largest living crocodilian species, growing to 6-7 meters in length and inhabits a very large area of northern Australia, Indonesia and Malaysia.
Treatment: Severe trauma or large predator injury (similar to head injury, limb injury due to falls, equipment crush, prop injuries). Call for help and immediate transport. Maintain open airway, keep face in nuetral position, be mindful of possible neck injury, direct pressure over bleeding wounds. Keep warm and treat for shock as needed.

Sharks
What do you think of first when you think of sharks?
Fearsome, big teeth, and unprovoked attacks on swimmers. Sharks, however, have many other interesting features that make them stand out from other denizens of the sea. The main difference from other fishes is that their skeleton is made from cartilage rather than bone. This cartilage makes sharks very flexible, allowing them to twist 360 degrees and whirl around and bite an unsuspecting diver or fisherman.
Sharks don 't have an air bladder, and if they stop swimming they will sink. To overcome this disadvantage, they have very large, oil-filled livers giving them some buoyancy. An advantage of not having a swim bladder is that it gives sharks great vertical mobility allowing them to rapidly move upward in the water column without the development of bends. In addition, their pectoral fins act as glide-planes and provide great lift as the shark
swims.
Sharks have many other interesting characteristics. Shark meat has an unpleasant taste due to the presence of high concentrations of the waste product urea in the tissue. Sharks store urea to maintain an osmotic balance with seawater so as not to have a water loss problem. Shark reproduction is very different from that of most bony fishes, having a very low output from their internal fertilization and production of large young. Sharks also have very low growth rates, a problem that is compounded by overfishing. An interesting sense that sharks possess is one called electroreception. There is a system of jelly-filled pores around the head and mouth called "ampullae of Lorenzini" that can detect small electric fields of less than 0.01 microvolt. This has been used to develop a small shark repelling apparatus for divers to wear that seems to be effective in warding off sharks.
Sharks can see color, as indicated by the presence of cone cells in their retinas. Similar to cats, they have a light-reflecting layer to enhance their night vision. This is important to divers to realize that swimming and diving in shark infested waters at night is more dangerous. The reason that chumming works so well in attracting sharks is their acute sense of smell. This could be a warning not to dive with even the smallest cut or abrasion. The most economically important sharks are the sandbar, bull, and lemon which do not mature until about 12 to 18 years of age. Slow growth is the norm; for example, a tagged immature male sandbar shark was recaptured 15 years later and had only grown about 19 inches and was still immature.
Sharks do not attack humans for the sole purpose of hunger. In fact, sharks do not know what the feeling of hunger is, and in fact, can go for many months without eating. This is not to say that sharks do not attack with the intention of seeking prey. Many attacks on divers and surfers especially can be attained to searching for food. To a shark, a surfer on a surfboard slightly resembles that of a seal or sea lion, or a diver in a black wetsuit can look like other prey.
Sharks also attack humans because they have been provoked or agitated by the person. Many spear-fishers have been attacked by reef sharks because when they spear fish, the blood from the fish and it 's vibrations can sometimes result in a feeding frenzy by many sharks. Bright colours can also be counted for attacks. As many people have believed in the past, sharks do in fact can see colours, and do indeed have very good eyesight. Avoid wearing the colours of orange and yellow, as this can aggravate the shark, and possibly lead to attacks. Sharks are in fact attracted by splashing and vibrations in the water, and it can sometimes be attributed to attacks. Most scientists have not been able to predict why and where sharks attacks.
The following is a list of preventative measures you, as a swimmer or diver can do to prevent the possibility of shark attacks:
Do not tease or entice sharks!
If you cut or injure yourself... get out! Do not stay in the water with blood around you. Sharks can smell blood from over a mile away. And, for the women who read this, if you are in the middle of your menstrual period, please stay out of the water for your own sake.
Watch other fish and turtles in the area--if they start acting erratic--be alert that a shark might be in the area.
Do not swim in waters that have been deemed dangerous. Avoid swimming in murky waters. If you feel something brush up against you.... get out of the water to check to make sure that you have not been bitten. Many shark attack victims have noted the lack of pain from being bitten, doctors and scientists have not been able to conclude why this occurs.. so if you have been brushed against by something, get out and investigate. Finally, if you don 't feel right in the water. Then get out! Nothing can be said for "gut feeling."
Watch other fish and turtles in the area--if they start acting erratic--be alert that a shark might be in the area.
Most shark attacks are fortunately not fatal, however, there are a percentage of attacks that are fatal. There are only 4 sharks who consistently attack people: The Great White, The Tiger, The Bull, and The Oceanic White Tip. There are, however, other large sharks that have attacked humans, and can potentially dangerous.
When most sharks attack, the first bite is usually a "tester." Like most people, when sampling food, they bite once, revel in the taste, and then decide whether or not to continue... with most sharks, sampling occurs as well. The trouble is, with the sampling of a Great White or other larger predatory sharks, the first bite is so massive or severe that many people die from their injuries, and do not actually die from being consumed. A lot of fatalities can be attributed to people bleeding to death or dying from shock.
There are different modes of shark attacks and investigations that sharks go through when they come across humans. The following list shows what a shark can do when it comes across a human.
Indifference (rare)
Approach with swift visual inspection from a distance without follow-up
Approach with surveillance circling - without follow up or follow-up, contact and attack
Approach with brush-past, without follow-up (wounding possible)
Charge with collision (upwards trajectory generally)
Charge with single or double investigative bite without tearing
Charge with biting and removal of flesh (death in 45% of cases)
Multiple feeding-frenzy charge (death in 100% of cases)

FACTS & STATS ON MARINE HAZARDS Box jellyfish have been known to kill people within three minutes, blue-ringed octopus in 30 minutes and pufferfish (eaten) in 17 minutes. At least 65 people have been killed by box jellyfish in the last century, over 30 of them on beaches between Mackay and Cairns. Aboriginal people long knew about box jellyfish, but it was not until after the death of a five-year-old boy at Cardwell, in 1955, that Chironex fleckeri ' was identified by scientists. The irukandji (Carukia barnesi) was first scientifically identified in 1961 by Cairns doctor, John Barnes. He named it after the local Irukandji Aboriginal people. Toad/pufferfish are not only poisonous to eat but can, with their beak-like mouths, remove toes and fingers. Ancient laws worldwide forbade consumption of these species - fish without scales are classed as 'unclean ' in the Old Testament. At the base of the tails of the aptly named surgeon fish are razor sharp blades which can inflict nasty cuts. No venom, however, is involved. You are more likely to die from a box jellyfish sting than a shark attack. Reef sharks are not normally aggressive to humans but should be treated with respect. Do not carry bleeding fish and avoid swimming after dark.

http://www.horseshoecrab.org/med/med.html
How does the horseshoe crab protect the public health?
The horseshoe crab plays a vital, if little-known, role in the life of anyone who has received an injectable medication. An extract of the horseshoe crab 's blood is used by the pharmaceutical and medical device industries to ensure that their products, e.g., intravenous drugs, vaccines, and medical devices, are free of bacterial contamination. No other test works as easily or reliably for this purpose. Read below for more detail.
Why are we concerned about bacterial contamination of pharmaceutical products?
Bacteria are everywhere-from our intestinal tract, to soils, rivers, and oceans. For the most part, bacteria are beneficial, acting to degrade organic waste and recycle nutrients back into the food chain. Sometimes, however, bacteria cause disease. We are all familiar with many specific bacterial diseases such as Salmonella food poisoning or more serious ones such as Cholera and Tetanus.
Bacteria that cause these diseases are referred to as pathogens and usually require an animal host for multiplication or transmission even though they may persist in a soil or aquatic environment for long periods of time. Other bacteria, generally considered non-pathogenic, can cause disease if they enter parts of our body that are usually bacteria-free, such as the bloodstream. In this case, even the ordinarily benign gut bacterium E. coli can cause sepsis and death. Therefore, the pharmaceutical industry takes great care in producing drugs, vaccines, and medical devices (items that deliver drugs or are implanted) that are sterile-free of living microorganisms. Unfortunately, certain bacterial components can, in and of themselves, be toxic. Thus, pharmaceutical manufacturers not only need to be sure their products are sterile but also non-toxic, i.e., contain no bacterial components left from pre-sterilization bacterial contamination.

Illustration credit Charles River Endosafe, SC

The bacterial toxin of greatest concern is termed endotoxin, and it is able to withstand steam sterilization. Endotoxin occurs as part of the cell structure of a large class of bacteria that includes both pathogens and non-pathogens. This class of bacteria is known as Gram-negative, for their characteristic of being easily decolorized during the Gram staining procedure. Surprisingly, it is the non-pathogenic members of the Gram-negative group, those that love aquatic environments, which cause the most problems for the pharmaceutical industry.
Over fifty years ago it was recognized that some sterile solutions, when injected into humans or rabbits, caused a fever or pyrogenic response. Scientists soon learned that these so-called "injection fevers" were caused by endotoxin (a potent pyrogen) left over from bacterial components that remained in the injected solutions after sterilization. Fortunately, it was also found that solutions could be screened for pyrogens by injecting small amounts of the batch into rabbits. If the rabbit exhibited a fever, the solution was deemed pyrogenic and was rejected. The rabbit or pyrogen test, along with a sterility test, became the two most important tools of the pharmaceutical industry. The Pyrogen Test employing rabbits is still in limited use, although as you will see below, an endotoxin test using an extract from the blood cells of the horseshoe crab is the predominant pyrogen test today.
How was the horseshoe crab test discovered?
In the 1960 's, Dr. Frederik Bang, a Johns Hopkins researcher working at the Marine Biological Laboratory in Woods Hole, Massachusetts, found that when common marine bacteria were injected into the bloodstream of the North American horseshoe crab, Limulus polyphemus, massive clotting occurred. Later, with the collaboration of Dr. Jack Levin, the MBL team showed that the clotting was due to endotoxin, a component of the marine bacteria originally used by Dr. Bang. In addition, these investigators were able to localize the clotting phenomenon to the blood cells, amebocytes, of the horseshoe crab, and, more importantly, to demonstrate the clotting reaction in a test tube. The cell-free reagent that resulted was named Limulus amebocyte lysate, or LAL. The name LAL is extremely descriptive: Limulus is the generic name of the horseshoe crab, amebocyte is the blood cell that contains the active components of the reagent, and lysate describes the original process used by Levin and Bang to obtain these components. In Levin and Bang 's process, amebocytes, after being separated from the blue-colored plasma (hemolymph), were suspended in distilled water where they lysed (ruptured) due to the high concentration of salt contained in the amobocytes versus the absence of salt in the distilled water. Surprisingly, this same process with some minor modifications is still used today to produce LAL.
How does the horseshoe crab protect itself from disease?
One may wonder why the horseshoe crab is sensitive to endotoxin and, furthermore, how does the crab benefit from this phenomenon? As we know, seawater is a virtual "bacterial soup". Typical near-shore areas that form the prime habitat of the horseshoe crab can easily contain over one billion Gram-negative bacteria per milliliter of seawater. Thus, the horseshoe crab is constantly threatened with infection. Unlike mammals, including humans, the horseshoe crab lacks an immune system; it cannot develop antibodies to fight infection. However, the horseshoe crab does contain a number of compounds that will bind to and inactivate bacteria, fungi, and viruses. The components of LAL are part of this primitive "immune" system. The components in LAL, for example, not only bind and inactivate bacterial endotoxin, but the clot formed as a result of activation by endotoxin provides wound control by preventing bleeding and forming a physical barrier against additional bacterial entry and infection. It is one of the marvels of evolution that the horseshoe crab uses endotoxin as a signal for wound occurrence and as an extremely effective defense against infection.
How are the horseshoe crabs collected? Are they harmed?
In shallow water, horseshoe crabs are collected by hand from a small boat using a clam rake, and the animals are not injured during this process. In deeper water, a dredge is used, and in this case, some horseshoe crabs do get injured. Injured crabs are released immediately and most will survive. It is quite common to find crabs with "scars" of old injuries that have healed.
Once the crabs are caught, they are transported to the laboratory from the fishing pier by truck. Sometimes a refrigerated truck is used, but as long as the animals are kept cool and dark during transport, they exhibit no adverse affects. During the bleeding process, up to 30% of the animal 's blood is removed. Research has shown that once returned to the water, the horseshoe crab 's blood volume rebounds in about a week.
It takes longer for the crab 's blood cell count to return to normal, about two to three months. Theoretically, crabs can be bled several times a year, but LAL manufacturers bleed them only once per year.
The Associates of Cape Cod and other LAL manufacturers have studied horseshoe crab mortality following the bleeding procedure and have found it to be quite low, less than 3% when compared to controls handled similarly but not bled. There are no records of a horseshoe crab dying during the bleeding process itself. Other studies conducted by government agencies and universities indicate a mortality of 10-15%. However, the horseshoe crabs in these studies were not handled as carefully as those collected by the LAL industry.
Studies done by the Associates of Cape Cod show that not only do the crabs survive one bleeding, but that they can be captured year after year to donate their life-saving blood-much like human blood donors. In addition, their studies indicate that crabs, which are bled and returned to their spawning area, will continue their breeding activity without any ill effect.
The companies that produce LAL go to great lengths to ensure that the animals used in the making this valuable, life-saving test are handled with care and respect. They recognize that a stable horseshoe crab population is vitally important not only to the biomedical community, but also to the survival of millions of shorebirds, sea turtles, and other marine creatures that have a symbiotic relationship with this remarkable creature. These companies will continue to support sound, scientifically-based conservation measures that will ensure a sustainable population for the future.

Product

Bleeding

Bottling

Collecting
Photographs provided by Associates of Cape Cod
How was LAL commercialized?
In the 1970 's, Dr.
Stanley Watson, a scientist at the Woods Hole Oceanographic Institution located across the pond from the MBL, began using the LAL reagent in his research with marine bacteria. Since no commercial reagent existed, Dr. Watson set up production for his own use. However, word quickly spread that Dr. Watson was sharing excess reagent, not only with other scientists interested in bacterial endotoxin, but also with pharmaceutical companies interested in using LAL as an in-process control for endotoxin contamination. When the demand for LAL outpaced supply, Dr. Watson decided to set up a small company, Associates of Cape Cod, Inc. To reward his efforts, Dr. Watson 's company was granted the first Food and Drug Administration license to manufacture and sell LAL. As the LAL became accepted as a replacement for the rabbit pyrogen test and global demand for the reagent grew, other US companies and one Japanese company were licensed. Today LAL is made in the US, Japan, and China. Commercial LAL is produced in a manner nearly identical to the procedure described by Levin and Bang, albeit on a larger scale. While Levin and Bang used their lysate directly in their experiments, commercial LAL is freeze-dried to give it a longer shelf life and allow for easier
shipping.
How is an LAL test performed?
To use the commercial product, a laboratory reconstitutes the vial of freeze-dried LAL with endotoxin-free water. An equal amount of reconstituted LAL, usually 0.1 ml, is then added to the sample solution in a small, glass, endotoxin-free test tube. The mixture is then incubated at 37C for one hour. At the end of this time, the mixture is examined for gel formation by gently inverting the tube. If sufficient endotoxin was present in the sample, a firm gel, one that can withstand inversion of the tube, is formed. Knowing the sensitivity of the LAL then allows the investigator to determine the quantity of endotoxin in the sample. If the sample is found to contain an amount that exceeds the limit set by the FDA, the sample fails and the lot of pharmaceutical product must be rejected. The US FDA currently requires the LAL test to be performed on all human and animal injectables as well as medical devices used to deliver these injectables. In addition, many implantable devices and artificial kidneys used for renal dialysis also require an LAL test.
Are there other uses for LAL?
Since LAL detects endotoxin, a component of Gram-negative bacteria, the test can also be used to detect the presence of these bacteria. However, there are two major drawbacks:
1. LAL cannot discriminate between living and dead bacteria, and
2. LAL cannot differentiate species of bacteria-endotoxin, which cause a similar reaction with LAL.

Even with these drawbacks, the LAL test has been used to rapidly diagnose urinary tract infections and spinal meningitis. In these cases, the presence of endotoxin is almost always indicative of living bacteria, i.e., an infection, and the types of bacteria causing these infections are few and quite similar. The LAL test has also been used to assess food spoilage (fish, milk, ground beef), air and water quality, and (in experiments) to determine the ability of new drugs to neutralize the toxic effects of endotoxin.
Are there other compounds in the horseshoe crab that are of biomedical interest?
Besides LAL, a number of reagents and medically useful compounds have been discovered in the blood of the horseshoe crab. These include:
A new test for fungal infections (G-Test) which is already in use in Japan and is expected to be licensed in the US next year
An endotoxin-neutralizing protein which has potential as an antibiotic as well as an alternative endotoxin assay. This protein, ENP, can be made synthetically, which would eliminate the use of live horseshoe crabs for the LAL reagent.
A number of other proteins that show anti-viral and anti-cancer activity.
Written for ERDG by: Thomas J. Novitsky, Ph.D.
Edited by: Lisa Smith
Infectious diseases are the third cause of death in the United States and are the leading cause worldwide. The LAL is a major tool in the development of new antibiotics and vaccines.
LAL Manufacturers
Associates of Cape Cod, MA
Charles River
Lonza Walkersville Inc.
Horseshoe Crabs and Vision
It was in 1926 that H. Keffer Hartline began to study electrical impulses from the optic nerve of horseshoe crab eyes. From these studies, some important principles about the function of human eyes were discovered. As a result, Dr. Ragnar Granit of Sweden and Americans H. Keffer Hartline and George Wald were awarded the 1967 Nobel Prize in Medicine.
Chitin
The chitin from horseshoe crabs is used in the manufacturing of chitin-coated filament for suturing and chitin-coated wound dressing for burn victims (Hall, 1992). Since the mid-1950s, medical researchers have known that chitin-coated suture material reduces healing time by 35 to 50 percent.
Pharmaceutical, Biomedical and LAL Industry Sponsors of Horseshoe Crab Conservation
Lonza Walkersville Inc.
Charles River Endosafe, SC

http://marinebio.org/oceans/deep/
The Deep Sea
The Ocean / NEXT: Research Tools & Methods » Over 60% of our planet is covered by water more than a mile deep. The deep sea is the largest habitat on earth and is largely unexplored. More people have traveled into space than have traveled to the deep ocean realm.... - The Blue Planet Seas of Life
Most people familiar with the oceans know about life only in the intertidal zone, where the water meets land, and the epipelagic zone, the upper sunlit zone of the open ocean. Though these zones contain an abundance of ocean life because sunlight is available for photosynthesis, they make up only a small fraction of the ocean biome. In fact, most of the ocean is cold, dark and deep. It is important to realize that photosynthesis occurs only down to about 100 - 200 m, and sunlight disappears altogether at 1,000 m or less, while the ocean descends to a maximum depth of about 11,000 m in the Mariana Trench!
To get an idea of how vast the ocean 's depths are, consider that 79% of the entire volume of the earth 's biosphereconsists of waters with depths greater than 1,000 m. Until recently, the deep sea was largely unexplored. But advances indeep sea submersibles and image capturing and sampling technologies are increasing the opportunities for marine biologists to observe and uncover the mysteries of the deep ocean realm.

Deep sea research is vital because this area is such an enormous part of the biosphere. Despite its depth and distance, it is still our backyard in comparison to outer space. And yet, human exploration has revealed more detail about the surface of the moon and Mars that it has about the deep sea! Consider that hydrothermal vents and their unique organisms, which revolutionized our ideas about energy sources and the adaptability of life, were only discovered in 1977. There may be yet other life-altering discoveries to be found at the bottom of the ocean.

The oceans are divided into two broad realms; the pelagic and the benthic. Pelagic refers to the open water in which swimming and floating organisms live. Organisms living there are called the pelagos. From the shallowest to the deepest, biologists divide the pelagic into the epipelagic (less than 200 meters, where there can be photosynthesis), the mesopelagic (200 - 1,000 meters, the "twilight" zone with faint sunlight but no photosynthesis), the bathypelagic (1,000 - 4,000 meters), the abyssopelagic (4,000 - 6,000 meters) and the deepest, the hadopelagic (the deep trenches below 6,000 meters to about 11,000 m or 36,000 feet deep). The last three zones have no sunlight at all.
Benthic zones are defined as the bottom sediments and other surfaces of a body of water such as an ocean or a lake. Organisms living in this zone are called benthos. They live in a close relationship with the bottom of the sea, with many of them permanently attached to it, some burrowed in it, others swimming just above it. In oceanic environments, benthic habitats are zoned by depth, generally corresponding to the comparable pelagic zones: the intertidal (where sea meets land, with no pelagic equivalent), the subtidal (the continental shelves, to about 200 m), the bathyal (generally the continental slopes to 4,000 m), the abyssal (most of the deep ocean seafloor, 4,000 - 6,000 m), and the hadal (the deep trenches 6,000 to 11,000 m).
There are several types of deep benthic surfaces, each having different life forms. First, most of the deep seafloor consists of mud (very fine sediment particles) or "ooze" (defined as mud with a high percentage of organic remains) due to the accumulation of pelagic organisms that sink after they die. [Unlike the shoreline, sandy habitats are rarely found in the deep sea because sand particles, created by wave action on coral and rocks at shorelines, are too heavy to be carried by currents to the deep.] Second, benthic areas too steep for sediment to stick are rocky. Rocky areas are found on the flanks of islands, seamounts, rocky banks, on mid-ocean ridges and their rift valleys, and some parts of continental slopes. At the mid-ocean ridges, where magma wells up and pushes seafloor tectonic plates apart, even flat surfaces are rocky because these areas are too geologically new to have accumulated much mud or ooze. Third, in some areas certain chemical reactions produce unique benthic formations. The best known of these formations are the "smoker" chimneys created by hydrothermal vents, which are described in detail below.
Exploration of these zones has presented a challenge to scientists for decades and much remains to be discovered. However, advances in technology are increasingly allowing scientists to learn more about the strange and mysterious life that exists in this harsh environment. Life in the deep sea must withstand total darkness (except for non-solar light such as bioluminescence), extreme cold, and great pressure. To learn more about deep-sea marine life, sophisticated data collection devices have been developed to collect observations and even geological and biological samples from the deep. First, advances in observational equipment such as fiber optics that use LED light and low light cameras has increased our understanding of the behaviors and characteristics of deep sea creatures in their natural habitat. Such equipment may be deployed on permanent subsea stations connected to land by fiber optic cables, or on "lander" devices which drop to the seafloor and which are later retrieved (typically after a radio command activates the dropping of ballast so the lander may float up.) Second, remotely operated vehicles (ROVs) have been used underwater since the 1950s. ROVs are basically unmanned submarine robots with umbilical cables used to transmit data between the vehicle and researcher for remote operation in areas where diving is constrained by physical hazards. ROVs are often fitted with video and still cameras as well as with mechanical tools such as mechanical arms for specimen retrieval and measurements. Other unmanned submarine robots include AUVs (autonomous undersea vehicles) that operate without a cable, and the USA 's new Nereus, a hybrid unmanned sub which can switch from ROV to AUV mode and which is currently the world 's only unmanned submarine capable of reaching the deepest trenches. Third, manned deep sea submersibles are also used to explore the ocean 's depths. Alvin is an American deep sea submersible built in 1964 that has been used extensively over the past 4 decades to shed light on the black ocean depths. Like ROVs, it has cameras and mechanical arms. This sub, which carries 3 people (typically a pilot and 2 scientists), has been used for more than 4,000 dives reaching a maximum depth of more than 4,500 m. France, Japan and Russia have similar manned scientific submersibles that can reach somewhat greater depths, while China is currently building one to reach 7,000 m.

The bathyscaphe Trieste at the National Museum of the U.S. Navy in Washington, D.C.
Until 2012, only one manned submarine device has ever reached the bottom of Mariana trench at almost 11,000 m: the bathyscaphe Trieste manned by Jacques Piccard and Don Walsh. During the Trieste 's single dive in 1960, its windows began to crack, and it has never been used since. 52 years later, on March 25, 2012 (March 26 local time), James Cameron successfully dove in his commissioned one-man sub to the Challenger Deep. Don Walsh was invited to join the expedition.
Physical Characteristics of the Deep Sea
The physical characteristics that deep sea life must contend with to survive are:
1. abiotic (non-living) ones, namely light (or lack thereof), pressure, currents, temperature, oxygen, nutrients and other chemicals; and
2. biotic ones, that is, other organisms that may be potential predators, food, mates, competitors or symbionts.
All these factors have led to fascinating adaptions of deep sea life for sensing, feeding, reproducing, moving, and avoiding being eaten by predators.
Light
The deep sea begins below about 200 m, where sunlight becomes inadequate forphotosynthesis. From there to about 1,000 m, the mesopelagic or "twilight" zone, sunlight continues to decrease until it is gone altogether. This faint light is deep blue in color because all the other colors of light are absorbed at depth. The deepest ocean waters below 1,000 m are as black as night as far as sunlight is concerned. And yet, there IS some light. People who dive deep in a submersible (with its lights off) are often mesmerized by an incredible "light show" of floating, swirling, zooming flashes of light. This is bioluminescence, a chemical reaction in a microbe or animal body that creates light without heat, and it is very common. And yet, this light is low compared to sunlight, so animals here — as well as those in the mesopelagic zone — need special sensory adaptations. Many deep-sea fish such as the stout blacksmelt have very large eyes to capture what little light exists. Other animals such as tripodfishes are essentially blind and instead rely on other, enhanced senses including smell, touch and vibration.
Scientists think bioluminescence has six different functions (not all used by any one species):
1. headlights, such as the forward-facing light organs (called photophores) of lantern fish;
2. social signals such as unique light patterns for attracting mates;
3. lures to attract curious prey, such as the dangling "fishing lures" of anglerfish;
4. counterillumination, in which rows of photophores on the bellies of many mesopelagic fish produce blue light exactly matching the faint sunlight from above (making the fish invisible to predators below them);
5. confusing predators or prey, such as bright flashes that some squid make to stun their prey, and decoys that divert attention, such as the glowing green blobs ejected by green bomber worms; and
6. "burglar alarms" in which an animal being attacked illuminates its attacker (the "burglar") so that an even bigger predator (the "police") will see the burglar and go after it. Some swimming sea cucumbers even coat their attackers with sticky glowing mucus so the "police" predators can find them many minutes later.
Most bioluminescence is blue, or blue-green, because those are the colors that travel farthest in water. As a result, most animals have lost the ability to see red light, since that is the color of sunlight that disappears first with depth. But a few creatures, like the dragonfish, have evolved the ability to produce red light. This light, which the dragonfish can see, gives it a secret "sniper" light to shine on prey that do not even know they are being lit up!
Pressure
Considering the volume of water above the deepest parts of the ocean, it 's no wonder that hydrostatic pressure is one of the most important environmental factors affecting deep sea life. Pressure increases 1 atmosphere (atm) for each 10 m in depth. The deep sea varies in depth from 200 m to about 11,000 m, therefore pressure ranges from 20 atm to more than 1,100 atm. High pressures can cause air pockets, such as in fish swim bladders, to be crushed, but it does not compress water itself very much. Instead, high pressure distorts complex biomolecules — especially membranes andproteins — upon which all life depends. Indeed, many food companies now use high pressure to sterilize their products such as packaged meats.
Life appears to cope with pressure effects on biomolecules in two ways. First, their membranes and proteins have pressure-resistant structures that work by mechanisms not yet fully understood, but which also mean their biomolecules do not work well under low pressure in shallow waters. Second, some organisms may use "piezolytes" (from the Greek "piezin" for pressure). These are small organic molecules recently discovered that somehow prevent pressure from distorting large biomolecules. One of these piezolytes is trimethylamine oxide (TMAO). This molecule is familiar to most people because it gives rise to the fishy smell of marine fish and shrimp. TMAO is found at low levels in shallow marine fish and shrimp that humans routinely eat, but TMAO levels increase linearly with depth and pressure in other species. Really deep fish, including some grenadiers which humans are now fishing, smell much more fishy!
Animals brought from great depth to the surface in nets and submersible sample boxes generally die; in the case of some (but not most) deep-sea fishes, their gas-filled swim bladder (adapted to resist high pressure) expands to a deadly size. However, the vast majority of deep-sea life has no air pockets that would expand as pressure drops during retrieval. Instead, it is thought that rapid pressure as well as temperature changes kill them because their biomolecules no longer work well (high TMAO does not help, as it appears to be too high in deep-sea life for biomolecules to work properly at the surface). Advances in deep sea technology are now enabling scientists to collect species samples in chambers under pressure so that they reach the surface for study in good condition.
Pressure-adapted microbes have been retrieved from trenches down to 11,000 m, and have been found in the laboratory to have all these adaptations (pressure-resistant biomolecules and piezolytes). However, pressure adaptations have only been studied in animals down to about 5,000 m. We do not yet know if the adaptations found at those depths work at greater depths down to 11,000 m.
Temperature
Except in polar waters, the difference in temperature between the euphotic, or sunlit, zone near the surface and the deep sea can be dramatic because of thermoclines, or the separation of water layers of differing temperatures. In the tropics, for example, a layer of warm water over 20°C floats on top of the cold, dense deeper water. In most parts of the deep sea, the water temperature is more uniform and constant. With the exception of hydrothermal vent communities where hot water is emitted into the cold waters, the deep sea temperature remains between about -1 to about +4°C. However, water never freezes in the deep sea (note that, because of salt, seawater freezes at -1.8°C). If it did somehow freeze, it would just float to the surface as ice! Life in the deep is thought to adapt to this intense cold in the same ways that shallow marine life does in the polar seas. This is by having "loose" flexible proteins and unsaturated membranes which do not stiffen up in the cold. Membranes are made of fats and need to be somewhat flexible to work well, so you may be familiar with this adaptation in your kitchen. Butter, a saturated fat, is very hard in your refrigerator and would make a poor membrane in the cold, while olive oil — an unsaturated fat — is semi-solid and would make a good flexible membrane. However, as with pressure, there is a tradeoff: loose membranes and proteins of cold-adapted organisms readily fall apart at higher temperatures (much as olive oil turns to liquid at room temperature).
Oxygen
The dark, cold waters of much of the deep sea have adequate oxygen. This is because cold water can dissolve more oxygen than warm water, and the deepest waters generally originate from shallow polar seas. In certain places in the northern and southern seas, oxygen-rich waters cool off so much that they become dense enough to sink to the bottom of the sea. These so-called thermohaline currents can travel at depth around the globe, and oxygen remains sufficient for life because there is not enough biomass to use it all up. However, there are also oxygen-poor environments in intermediate zones, wherever there is no oxygen made by photosynthesis and there are no thermohaline currents. These areas, called oxygen minimum zones, usually lie at depths between 500 - 1,000 m in temperate and tropical regions. Here, animals as well as bacteria that feed on decaying food particles descending through the water column use oxygen, which can consequently drop to near zero in some areas. Biologists are still investigating how animals survive under such conditions.
Although most of the deep seafloor has oxygen, there are exceptions in isolated basins with no circulation. Some of these basins that have no oxygen are found at the bottom of the Mediterranean Sea. In 2010, scientists investigating these at3,000 m depths made a startling discovery: the first known animals to be living continuously without any oxygen. The animals are tiny Loriciferans, members of an animal phylum first discovered in 1983. How they can survive these conditions is not yet known [see Animals thrive without oxygen at sea bottom].
Food
Deep sea creatures have evolved some fascinating feeding mechanisms because food is scarce in these zones. In the absence of photosynthesis, most food consists of detritus — the decaying remains of microbes, algae, plants and animals from the upper zones of the ocean — and other organisms in the deep. Scavengers on the seafloor that eat this "rain" of detritus include sea cucumbers (the most common benthic animal of the deep), brittle stars (seen in the photo above), and grenadier or rattail fish. The corpses of large animals such as whales that sink to the bottom provide infrequent but enormous feasts for deep sea animals and are consumed by a variety of species. This includes jawless fish such as hagfish, which burrow into carcasses, quickly consuming them from the inside out; scavenger sharks; crabs; and a newly discovered group of worms (called Osedax, meaning bone-eater) which grow root-like structures into the bone marrow!
Deep-sea pelagic fish such as gulper eels have very large mouths, huge hinged jaws and large and expandable stomachs to engulf and process large quantities of scarce food. Many deep-sea pelagic fish have extremely long fang-like teeth that point inward. This ensures that any prey captured has little chance of escape. Some species, such as the deep sea anglerfish and the viperfish, are also equipped with a long, thin modified dorsal fin on their heads tipped with a photophore lit with bioluminescence used to lure prey. Many of these fish don 't expend much energy swimming in search of food; rather they remain in one place and ambush their prey using clever adaptations such as these lures. Others, such as rattails or grenadiers (pictured below) cruise slowly over the seafloor listening and smelling for food sources failing from above, which they engulf with their large mouths.

Many mesopelagic and deeper pelagic species also save energy by having watery, gelatinous muscles and other tissues with low nutritive content. For example, an epipelagic tuna 's muscle (the kind you might eat) may be 20% protein. This makes for a strong, fast muscle, but also takes considerable energy to maintain. In contrast, a deep pelagic blacksmelt or viperfish may have only 5-8% protein. This means they cannot swim as well as a tuna, but they can achieve a larger body size with much less maintenance costs.
Some mesopelagic species have adapted to the low food supply (and sometimes to the low oxygen content) in moderate-depth waters with a special behavior called vertical migration. At dusk, millions of lantern fish, shrimp, jellies and other mobile animals migrate to the food-rich surface waters to feed in the darkness of night. Then, presumably to avoid being eaten in daylight, they return to the depths at dawn to digest. Some of the species undergo large pressure and temperature changes during their daily migrations, but we do not yet know exactly how they cope with those dramatic daily changes.
Since plankton is scarce in the deep sea, filter feeding (the most common mode of feeding in shallow waters) is a difficult way to make a living. Consequently, some deep-sea animals belonging to groups once thought to be exclusively filter feeders have evolved into carnivores! One of these is the carnivorous sea squirt Megalodicopia hians. Sea squirtsor tunicates are generally harmless filter feeders which draw in microscopic organisms through a siphon tube, butMegalodicopia hians has a huge jaw-like siphon that can rapidly engulf swimming animals! Another of these is the ping-pong-tree sponge, Chondrocladia lampadiglobus. Again, the vast majority of sponges draw in microscopic material through tiny pores, but this sponge has tree-like branches with large glass globes covered in Velcro-like sharp spikes that impale swimming prey!

Submarine canyons provide mixed blessings for seafloor life
Other Adaptations of Deep-sea Animals
We 've described many of the unique adaptations that animals of the deep-sea have evolved to cope with their harsh environment. Let 's look at some others, not all of which are fully understood.
1. Body Color: This is often used by animals everywhere for camouflage and protection from predators. In the deep sea, animals ' bodies are often transparent (such as many jellies and squids), black (such as blacksmelt fish), or even red (such as many shrimp and other squids). The absence of red light at these depths keeps them concealed from both predators and prey. Some mesopelagic fish such as hatchetfish have silvery sides that reflect the faint sunlight, making them hard to see.
2. Reproduction: Consider how hard it must be to find a mate in the vast dark depths. For most deep sea species, we do not know how they achieve this. Earlier we noted that unique light patterns may aid in this. Deep-sea anglerfish may use such light patterns as well as scents to find mates, but they also have another interesting reproductive adaptation. Males are tiny in comparison to females and attach themselves to their mate using hooked teeth, establishing a parasitic-like relationship for life. The blood vessels of the male merges with the female 's so that he receives nourishment from her. In exchange, the female is provided with a very reliable sperm source, avoiding the problem of having to locate a new mate every breeding cycle.
3. Gigantism: Another possible adaptation that is not fully understood is called deep-sea gigantism. This is the tendency for certain types of animals to become truly enormous in size. A well-known example is the giant squid, but there are many others such as the colossal squid, the giant isopod, the king-of-herrings oarfish(which may be the source of sea-serpent legends), and the recently captured giant amphipod from 7,000m in the Kermadec Trench near New Zealand. While the giant tubeworms of hydrothermal vents (see below) grow well due to abundant energy supplies, the other gigantic animals live in food-poor habitats, and it is not known how they achieve such growth. It may simply be a result of the feature we examine next: long lives.
4. Long Lives: Many deep-sea organisms, including gigantic but also many smaller ones, have been found to live for decades or even centuries. Long-lived fishes include rattails or grenadiers and the orange roughy, which are of special concern as they are targets of deep-sea fisheries. These species reproduce and grow to maturity very slowly, such that populations may take decades to recover (if at all) after being overfished. This has happened repeatedly to the orange roughy, a deep-sea fish easily found congregating around seamounts in the southern oceans. Once fisheries have wiped out one seamount population, they move on to another seamount. [see Rough seas for orange roughy: Popular U.S. fish import in jeopardy]
Also of concern with respect to their long, slow lives are a group of animals once thought to be restricted to warm tropical waters: corals. In the last 30 years, numerous cold-water coral species have been found on rocky surfaces throughout the deep sea. These animal colonies may live for centuries, or — amazingly — even millennia. One deep-sea coral colony off Hawaii has been dated at over 4,000 years old, making it older than the Pyramids of Egypt! [see Deep-Sea Corals May Be Oldest Living Marine Organism] Again, these corals are highly vulnerable to fisheries as they are easily destroyed by deep-sea trawl nets, and they may take decades to grow back. [see NOAA 's Coral Reef Conservation Program: Threats to Deep-sea Corals for more information]

Science at FMNH - Exploring Unknown Deep Sea Ecosystems
Hydrothermal Vent and Cold Seep Communities
Life in the deep sea is relatively sparse compared to the epipelagic (euphotic) and intertidal zones, with two exciting, and relatively recently discovered exceptions — hydrothermal vent and cold seep communities.
Hydrothermal Vents
These amazing formations were first discovered in 1976 - 77 during a deep sea expedition with Alvin at a mid-ocean ridge near the Galapagos. At that time, only geologists were aboard, with the goal of directly observing seafloor spreading — the mid-ocean ridges being places where magma welling up underneath pushes two tectonic platesapart, creating a rift valley between them. Some geologists thought there might be geyser-like hot springs, as found in rift valleys on land (such as in Iceland), while others thought that high pressure would prevent such formations. However no one predicted any interesting biology. What they found not only revolutionized geology but biology even more so. These dives to depths of about 2,700 m revealed hot springs of far greater complexity and beauty than anyone had imagined: hot mineral-rich water spewing (like continuous geysers) from vents heated by magma, with metal sulfides precipitating in the cold surrounding seawater to form intricate, colorful and often towering chimneys.
Moreover, a completely unexpected community of life was found around these aptly named hydrothermal vents, with not only high densities of numerous new species, but also a new kind of ecosystem flourishing in the dark that had never been imagined by scientists — an ecosystem based on toxic gas! The most amazing of the new species was a giant tubeworm, named Riftia. Growing rapidly in dense clusters, these 2-meter-tall worms were found to have no digestive tract. The revolutionary finding was that they subsist on energy-rich hydrogen sulfide in vent water and generated in the Earth 's crust. Hydrogen sulfide (rotten-egg gas) is normally toxic to animals, but these worms avoid the problem in a spectacular manner. They harbor bacteria known as chemoautotrophs (in a large sac replacing a digestive system), which can use the energy in hydrogen sulfide to convert carbon dioxide into sugars, just as plants do using sunlight. The worm 's blood picks up and delivers sulfide, carbon dioxide and oxygen to these bacterial symbionts, which in turn "feed" their hosts with the excess sugars they make (while turning the sulfide into a non-toxic waste product). Thus, the ecosystem was found to run on the Earth 's geothermal energy rather than sunlight. Many scientists now think that life on Earth began at such vents over 3 billion years ago.
Since those first discoveries near the Galapagos, hydrothermal vent communities have been found at depths ranging from about 1,500 m to over 5,000 m [see Expedition to Mid-Cayman Rise Identifies Unusual Variety of Deep Sea Vents]. Most vents are along the mid-ocean ridges, where magma is close to seawater. Other animals with bacterialsymbionts have been found, including other species of tubeworms, giant clams and mussels, snails, and shrimp. Undoubtedly many vent communities are yet to be found, since many ridge areas have not yet been explored.
The water temperature of vents is much warmer than normal for the deep sea (about 2°C), reaching as high at 400°Cwithout boiling due to the high pressure. However, nothing can live at such temperatures. The communities of vent life are mostly found between about 8 - 25°C, but may reach perhaps 60°C around some animals such as Pompeii worms (Alvinella). Though complex life seems not to live at higher temperatures, some archaea have been found living at temperatures of over 120°C!
IMCS Deep Sea Microbiology Lab videos: Black Smoker | Tube Worms | Pompeii Worms | Zoarcid Fish | Crabs
Cold Seeps
After the first vent discoveries, other unexpected high-density deep-sea ecosystems were found. Named cold seeps, these occur at places (mostly along continental margins) where cold methane (which at depths below 500 m forms methane-hydrate "ice"), hydrogen sulfide, and/or oil seep out of sediments to provide abundant energy. By some estimates, there is more energy locked up in themethane hydrates than in all (other) fossil/hydrocarbon fuels combined. Animals with symbiotic bacteria were found, different from but related to vent species, including tubeworms, clams, and mussels. Some mussels harbor methane-using bacteria instead of sulfide-using ones, making ecosystems powered by natural gas!
Dense seep communities have also been found around deep brine pools, or "lakes within oceans." These form where salt deposits under the ocean floor dissolve to form pools of water so dense from their salt content that they do not mix with the overlying seawater. So far a few of these have been found in the Gulf of Mexico and the Mediterranean Sea. At the best-studied brine pool (in the Gulf of Mexico: [see Lakes Within Oceans] high densities of mussels live around the rim, subsisting (using symbionts) on methane gas seeping from the pool. However, no known animal can survive the salt within the pool itself. Various microbes have been found in the high salt waters, however.
In 2012, a new deep-sea ecosystem dubbed a "hydrothermal seep" was discovered off Costa Rica. It is a mosaic of vent and seep communities, with many new species. See the news story "Hot Meets Cold at New Deep-Sea Ecosystem" for more information.
References
Marine Biology, an Ecological Approach, J.W. Nybakken, Benjamin Cummings, 1994. Chapter 4: Deep Sea Biology
Dive and Discover: Expeditions to the Seafloor - Woods Hole Oceanographic Institution NOAA Ocean Explorer
Deep-Sea Biology by Paul Yancey
Deep-Sea Biology, J.D. Gage & P.A. Taylor, Cambridge Univ. Press, 1992
Deep-Sea Fishes, D.J. Randall & A.P. Farrell, Academic Press, 1997
The Ecology of Deep-sea Hydrothermal Vents, C.L. Van Dover, Princeton Univ. Press, 2000
The Biology of the Deep Ocean, P. Herring, Oxford Univ. Press, 2001
The Silent Deep: The Discovery, Ecology, and Conservation of the Deep Sea, T. Koslow, Univ. Chicago Press, 2009.
Deep-Sea Biodiversity: Pattern and Scale by M.A. Rex and R.J. Etter, Harvard Univ. Press, 2010.
Lamellibrachia luymesi - Wikipedia

http://www.hsc.csu.edu.au/biology/core/balance/9_2_3/923net.html
Biology
Home > Biology > Core > Maintaining a balance > Maintaining a balance: 3. Gases, water and waste products
9.2 Maintaining a balance: 3. Gases, water and waste products
Syllabus reference (October 2002 version)
3. Plants and animals regulate the concentration of gases, water and waste products of metabolism in cells and in interstitial fluid
Students learn to: explain why the concentration of water in cells should be maintained within a narrow range for optimal function explain why the removal of wastes is essential for continued metabolic activity identify the role of the kidney in the excretory system of fish and mammals explain why the processes of diffusion and osmosis are inadequate in removing dissolved nitrogenous wastes distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney explain how the processes of filtration and reabsorption in the mammalian nephron regulate body fluid composition outline the role of the hormones, aldosterone and ADH (anti-diuretic hormone), in the regulation of water and salt levels in blood define enantiostasis as the maintenance of metabolic and physiological functions in response to variations in the environment and discuss its importance to estuarine organisms in maintaining appropriate salt concentrations describe adaptations of a range of terrestrial Australian plants that assist in minimising water loss
Students:
perform a first-hand investigation of the structure of a mammalian kidney by dissection, use of a model or visual resource and identify the regions involved in the excretion of waste products gather, process and analyse information from secondary sources to compare the process of renal dialysis with the function of the kidney present information to outline the general use of hormone replacement therapy in people who cannot secrete aldosterone analyse information from secondary sources to compare and explain the differences in urine concentration of terrestrial mammals, marine fish and freshwater fish use available evidence to explain the relationship between the conservation of water and the production and excretion of concentrated nitrogenous wastes in a range of Australian insects and terrestrial mammals process and analyse information from secondary sources and use available evidence to discuss processes used by different plants for salt regulation in saline environments perform a first-hand investigation to gather information about structures in plants that assist in the conservation of water
Extract from Biology Stage 6 Syllabus (Amended October 2002). © Board of Studies, NSW
[Edit: 2 Jun 09]
Prior learning: Science Stages 4 - 5 syllabus: Outcomes 5.7 (content 5.7.3 e and f: compounds and reactions), Outcome 4.8 (content 4.8.5 a: humans).
Preliminary course, module 8.3 (subsections 5 and 6).
Background information: Plants and animals carry out the normal functions for living on a daily basis. To do this, they require gases such as oxygen for respiration and, in plants, carbon dioxide for photosynthesis. These metabolic reactions are chemical reactions that accumulate wastes. If these wastes aren 't disposed of, they could kill the organism.

perform a first-hand investigation of the structure of a mammalian kidney by dissection, use of a model or visual resource and identify the regions involved in the excretion of waste products
Use the diagram below as a visual resource to identify the regions of the kidney, or use the models provided on these Internet sites.
Video of kidney dissected Broward Community College Ft. Lauderdale, Florida, USA
Before starting, consider safe working practices. Carry out a risk assessment by listing any potential dangers involved in this procedure and then say how you will avoid these dangers. If a mammalian kidney, such as a sheep 's kidney, is available, perform a dissection of it.

Identify the parts of the kidney using the diagram above as a guide.

explain why the concentration of water in cells should be maintained within a narrow range for optimal function
Water is the solvent for metabolic reactions in living cells. Many molecules and all ions important for the life of the cell are carried in an aqueous solution and these diffuse to reaction sites through the water in the cell. Metabolic reactions within the cell can occur only in solution where water is the solvent. It is critical for proper functioning of these reactions that the amount and concentration of water in the cell be kept constant. Most cells die when the water content is changed significantly.

explain why the removal of wastes is essential for continued metabolic activity
Metabolic wastes, particularly nitrogenous wastes that are the by-products of the breakdown of proteins and nucleic acids, are toxic to cells and must therefore be removed quickly. Nitrogenous wastes have the ability to change the pH of cells and interfere with membrane transport functions and may denature enzymes. Metabolic wastes are the product of metabolic reactions. If they are not removed their concentration in the cell increases. This inhibits the reactions that produce them, interfering with normal metabolic activity.

use available evidence to explain the relationship between the conservation of water and the production and excretion of concentrated nitrogenous wastes in a range of Australian insects and terrestrial mammals
Background
The following provides general information for the waste products, ammonia, urea and uric acid.
Ammonia is very toxic and must be removed immediately, either by diffusion or in very dilute urine. It is the waste product of most aquatic animals, including many fish and tadpoles. Ammonia is the immediate product of break down of amino acids — no energy is required to make it. It is highly soluble in water and diffuses rapidly across the cell membrane. However, it needs large quantities of water to be constantly and safely removed. Ammonia does not diffuse quickly in air.
Urea is toxic, but 10 000 times less toxic than ammonia, so it can be safely stored in the body for a limited time. It is the waste product of mammals, and some other terrestrial animals, but also of adult amphibians, sharks and some bony fish. It is made from amino acids but requires more steps and energy to make than does ammonia. It is highly soluble in water, but being less toxic than ammonia, it can be stored in a more concentrated solution and so requires less water to remove than ammonia. It is a source of water loss for these species.
Uric acid is less toxic than ammonia or urea, so can be safely stored in or on the body for extended periods of time. It is the waste product of terrestrial animals such as birds, many reptiles, insects and land snails. It is a more complex molecule than urea so it requires even more energy to produce. It is thousands of times less soluble than ammonia or urea and has low toxicity, which means that little water is expended to remove it. This is a great advantage for survival.
Organism
Terrestrial or aquatic
Waste product(s)
Explanation
spinifex hopping mouse of Central Australia terrestrial urea in a concentrated form
The animal lives in a very arid environment. It drinks very little water and excretes urea in a concentrated form, so that water can be conserved.
Euro, wallaroo (Macropus robustus) terrestrial concentrated urine
Euros have a very efficient excretory system that recycles nitrogen and urea to make a very concentrated urine. This allows them to survive in very arid environments
Insects
terrestrial uric acid
Insects are covered with a cuticle impervious to water. They conserve water by producing a dry paste of uric acid.
There is a fine balance between the use of water to remove nitrogenous wastes and conservation of water in the body. Australian terrestrial mammals that live in predominantly arid areas, such as the Bilby (Macrotus lagotus), must produce very concentrated urine and tolerate high levels of urea in their systems. Some insects excrete ammonia as a vapour across the body surface rather than as a solution of urine, an adaptation for conserving water. More commonly, uric acid is produced, which is a dry urate waste requiring no water to remove and with low toxicity so that it can be kept in the body for long periods of time. Find out how a range of Australian insects and terrestrial mammals excrete nitrogenous wastes. Use available evidence to examine cause and effect relationships such as the lack of water and the production of water-efficient waste removal and use this to write an explanation of the relationship between the conservation of water and the production and excretion of concentrated nitrogenous wastes in a range of Australian insects and terrestrial mammals.
Here are some starting points.
Euro University of Michigan, USA
Mulgara The Australian Arid Lands Botanic Garden, Port Augusta, South Australia
Kowari Animal Info, Maryland, USA (These websites last accessed 22 December 2005.)

analyse information from secondary sources to compare and explain the differences in urine concentration of terrestrial mammals, marine fish and freshwater fish
Some summary information is provided in the box below.
Excretory system of different animals Estrella Mountain Community College, Avondale, Arizona, USA
Present the information through use of an information organising device, such as the table below.
Type of organism
Excretory product and concentration
Environmental reason terrestrial mammal

marine fish

freshwater fish

Analyse the information by making generalisations about urine concentration of terrestrial mammals, marine fish and freshwater fish.
Summary: Differences in urine concentration of terrestrial mammals, marine fish and freshwater fish
Terrestrial mammals
Terrestrial mammals must work to find water and they are surrounded by air into which water quickly evaporates. Water conservation is of prime concern and these animals cannot excrete large quantities of water for the removal of metabolic waste.
Marine fish
The loss of water to the external environment is a problem that all marine fish must deal with. The marine environment in which the fish lives is hyperosmotic to the internal environment, i.e. there is a higher salt concentration in the water than inside the cells. This results in an osmotic gradient in which water is lost from the fish to the environment while ions are gained by diffusion. Ions are excreted by specialised glands.
Freshwater fish
The freshwater environment is hypo-osmotic to the internal environment of fish, i.e. there is a lower salt concentration in the water than inside the cells. This results in an osmotic gradient in which water is gained by the fish from the environment without drinking and salts are lost by diffusion. Ions are absorbed in the gut and by active uptake across the gills.

identify the role of the kidney in the excretory system of fish and mammals
The kidney is an organ of the excretory system of both fish and mammals. It plays a central role in homeostasis, forming and excreting urine while regulating water and salt concentration in the blood. It maintains the precise balance between waste disposal and the animal 's needs for water and salt. The role of the kidney in fish is dependant on the environment of the fish.
In marine (salt water) environments, the kidneys excrete small quantities of isotonic (same concentration as sea water) urine. This helps conserve water and excrete the excess salt they gain from their hyperosmotic environment.
In freshwater fish, the kidneys work continuously to excrete copious quantities of dilute urine, which also has a very low salt concentration. This helps to remove excess water gained from the hypo-osmotic environment.

explain why the processes of diffusion and osmosis are inadequate in removing dissolved nitrogenous wastes
Diffusion and osmosis are both examples of passive transport, relying on random movements of molecules. Diffusion is too slow for the normal functioning of the body and does not select for useful solutes. Osmosis only deals with the movement of water and thus would only allow water to move out of the body, not the nitrogenous wastes.

distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney
Active transport involves an expenditure of energy on the part of the organism, usually because the substance is moving against the concentration gradient, i.e. when a salt moves to an area of high salt concentration from an area of low salt concentration. Passive transport involves no expenditure of energy as the materials follow the natural concentration gradient, i.e. movement from an area of high concentration to an area of low concentration. Both diffusion and osmosis are examples of passive transport. In the mammalian kidney, both active and passive transport processes occur.
Passive transport: Once filtration has occurred in Bowman 's capsule, water returns via the interstitial fluid from the tubule to the capillary in the process of osmosis. This occurs along the length of the tubule.
Active transport: Depending on their concentration, the ions in the blood (Na+, K+, Cl- , H+ and HCO3) can be transported to cells in the nephron tubule and then secreted by the cells into the tubule. Some poisons and certain drugs are eliminated from the body in this manner.

explain how the processes of filtration and reabsorption in the mammalian nephron regulate body fluid composition
Filtration of the blood occurs in Bowman 's capsule where high blood pressure in the glomerulus forces all small molecules out of the blood into the capsule. Water, urea, ions (Na+, K+, Cl- , Ca2+, HCO3- ), glucose, amino acids and vitamins are all small enough to be moved into the glomerular filtrate. Blood cells and proteins are too large to be removed. This filtering process is non-selective and therefore many valuable components of the blood must be recovered by reabsorption. Reabsorption takes place selectively at various points along the proximal tubule, loop of Henle and distal tubule. All glucose molecules, amino acids and most vitamins are recovered, although the kidneys do not regulate their concentrations. The reabsorption of the ions Na+, K+, Cl- , Ca2+ and HCO3-occurs at different rates depending on feedback from the body. In some cases, active transport is required. Water is reabsorbed in all parts of the tubule except the ascending loop of Henle. The amount of water reabsorbed depends on feedback from the hypothalamus. If no water were reabsorbed human would soon dehydrate, losing water at a rate of around 7.5 L per hour. The chemical composition of the body fluids is precisely regulated by the control of solute reabsorption from the glomerular filtrate.

gather, process and analyse information from secondary sources to compare the process of renal dialysis with the function of the kidney
Gather information on renal dialysis using books and digital technology, including the Internet. Process the information by comparing the dialysis machine with the kidney and matching the parts of the dialysis machine to the structure of the kidney. You could use a table like the one following.
Dialysis machine
Kidney
artificial tubing nephron dialysing solution

distal tubule

Analyse the information by determining the outcomes of the dialysis process and showing whether the kidney is more efficient at osmoregulation and excretion than the dialysis machine.
Information from Davita.com .
Summary: Comparison of the process of renal dialysis with the function of the kidney
Dialysis means separation in Greek, and, like the nephrons of the kidney, the dialysis machine separates molecules from the blood removing some and returning others. The patient 's blood is pumped from an artery through tubes made of selectively permeable membrane. The artificial tubing allows only water and small solute molecules to pass through it into a dialysing solution that surrounds the tube. This dialysing solution is similar to the interstitial fluid found around nephrons. As the blood circulates through the dialysis tubing, urea and excess salts diffuse out of it instead of leaving by pressure filtration, as in the nephron. Those substances needed by the body, such as bicarbonate ions (HCO3 - ) diffuse from the dialysing solution into the blood (reabsorption). The machine continually discards used dialysing solution as wastes build up in it.
Two healthy kidneys filter the blood volume about once every half-hour. Dialysis is a much slower and less efficient process than the natural processes found in a healthy kidney but it is a lifesaver for those people with damaged kidneys.

outline the role of the hormones, aldosterone and ADH (anti-diuretic hormone), in the regulation of water and salt levels in blood
Aldosterone is a steroid hormone secreted by the adrenal gland. Its function is to regulate the transfer of sodium and potassium ions in the kidney. When sodium levels are low, aldosterone is released into the blood causing more sodium to pass from the nephron to the blood. Water then flows from the nephron into the blood by osmosis. This results in the homeostatic balance of blood pressure. Antidiuretic hormone (ADH or vasopressin) controls water reabsorption in the nephron. When levels of fluid in the blood drop, the hypothalamus causes the pituitary to release ADH. This increases the permeability of the collecting ducts to water, allowing more water to be absorbed from the urine into the blood. The resulting urine is more concentrated. When there is too much fluid in the blood, sensors in the heart cause the hypothalamus to reduce the production of ADH in the pituitary, decreasing the amount of water reabsorbed in the kidney. This results in a lower blood volume and larger quantities of more dilute urine.

present information to outline the general use of hormone replacement therapy in people who cannot secrete aldosterone
Background
Hypoaldosteronism is a condition where people fail to secrete aldosterone. Addison 's disease is the name of a disease with these symptoms which include high urine output with a resulting low blood volume. Eventually, as blood pressure falls, this can result in heart failure. A replacement hormone, fludrocortisone (Florinef), is used to treat this condition but a careful monitoring must be maintained to avoid fluid retention and high blood pressure.
Here is an Internet site to get you started in your search.
Addison 's disease National Institute of Diabetes and Digestive and Kidney Diseases, USA
Present the information as a discussion, with clearly identified issues and or points provided for and against the use of the therapy.

define enantiostasis as the maintenance of metabolic and physiological functions in response to variations in the environment and discuss its importance to estuarine organisms in maintaining appropriate salt concentrations
Enantiostasis is the maintenance of normal metabolic and physiological functioning, in the absence of homeostasis, in an organism experiencing variations in its environment. All organisms living in an estuary experience large changes in salt concentration in their environment over a relatively short time span, with the tidal movement and mixing of fresh and salt water. Organisms that must tolerate wide fluctuations of salinity are said to beeuryhaline. One strategy to withstand such changes in salt concentration is to allow the body 's osmotic pressure to vary with that of the environment. Organisms that do this, and therefore do not maintain homeostasis, are said to be osmoconformers. Most marine invertebrates are osmoconformers. In contrast, marine mammals and most fish are osmoregulators, maintaining homeostasis regardless of the osmotic pressure of the environment. However, as the salt concentration of body fluids in an osmoconformer changes, various body functions are affected, such as the activity of enzymes. For normal functioning to be maintained, another body function must be changed in a way that compensates for the change in enzyme activity. One example of enantiostasis is when a change in salt concentration in the body fluid, which reduces the efficiency of an enzyme, is compensated for by a change in pH, which increases the efficiency of the same enzyme.

process and analyse information from secondary sources and use available evidence todiscuss processes used by different plants for salt regulation in saline environments
Process information you have gathered, from the Internet or biology books about salt regulation of different plants in saline environments, by selecting the most relevant information and discarding peripheral information that is not as relevant. Analyse the information to see if there is a pattern of processes for regulating salt. Do certain families of plants use the same or similar methods or is the environment the plants live in more important in determining the methods of salt regulation? The two sites below will start you on your search. Use the evidence from your analysis to develop a discussion of the processes used by different named plants for salt regulation in saline environments.
Poster: Salinity American Society of Plant Biologists, USA
Description of Australia 's marine environment and its status, Coastal saltmarshes: undervalued and locally threatened Department of Environment, Water, Heritage and the Arts, Australian Government
Summary: Coping with salt
Most plants cannot tolerate high salt concentrations in the root zone as it leads to water stress. The salt accumulates in the leaves and is toxic. Enzymes are inhibited by Na+ ions. Halophytes are plants that can tolerate higher levels of salt in their environment.
The grey mangrove, Avicennia marina, has special salt glands in its leaves that excrete salt. Other mangroves exclude salts at their roots through ultrafiltration and a third mechanism is to store salt in leaves and then drop the leaves.
Another mechanism involves the efficient control of transpiration. Some mangroves have small leaves hanging vertically to reduce the surface presented to the sun and thus reducing transpiration.
Salt marsh plants also have mechanisms for salt regulation. For example, Sarcocornia quinqueflora accumulates salt in the swollen leaf bases which fall off, thus removing excess salt and Sporobolus virginicus has salt glands on its leaves.
Another form of salt stress can occur in salt laden air such as in coastal environments. Some coastal plants, such as the Norfolk Island pine, have a mesh of cuticle over their stomates, which prevents small water droplets from entering the leaf.

perform a first-hand investigation to gather information about structures in plants that assist in the conservation of water
This first-hand investigation is easily performed as an observation exercise, using local specimens. Look for plants that occur in areas where water conservation is important. As Australia is a dry continent, many of our plants have evolved to withstand periods of drought. So, no matter what part of NSW you live in, you should have some plants you can observe that grow nearby. Some plant species to look for are eucalyptus, casuarinas, paper barks, cacti and other succulents, spinifex and mulga. Gather information by observing and recording structures in plants that assist in the conservation of water. Many plants have adaptations to assist in the conservation of water. Here are a few adaptations to look for: the location and the number of stomates the arrangement, shape and size of the leaves phyllodes or cladodes rather than leaves presence of a thick waxy cuticle hairy leaves leaves reduced to spines leaves rolled inwards the reflective nature of the leaf surface.
Your recording could best be done using a table like the one below.
Plant
Adaptation of leaves
Adaptation of stems
Adaptation of roots
How this adaptation conserves water
Casuarina
leaves reduced to scales cladodes reduces transpiration
Eucalyptus
waxy leaves; leaves hang vertically

reduces transpiration
Cactus

stems store water

Describe adaptations of a range of terrestrial Australian plants that assist in minimising water loss
You will recall from the Preliminary course that the leaves of plants contain stomates or small pores that allow the exchange of gases essential for respiration and photosynthesis. These gases include water vapour, as well as oxygen and carbon dioxide. If stomates are open, there will be a loss of water by transpiration and evaporation. Plants in arid areas have to balance the need for CO2 with the need to conserve water. Adaptations of Australian xerophytes (plants adapted to dry conditions) include: hard leathery, needle-shaped leaves with reduced surface areas such as in Hakea sericea (needlebush) and coastal tea trees use of phyllodes for photosynthesis rather than leaves that would lose water by transpiration, as in many acacias some salt bushes, e.g. Atriplex, change the reflectiveness of their leaves during leaf development so that they have highly reflective leaves during summer
Eucalypts avoid high radiation in the middle of the day by hanging their leaves vertically to present less surface area to sun heat loss is greater for small leaves or highly dissected leaves than it is for larger leaves and many Acacias have fronds of bipinnate leaves waxy cuticle prevents evaporation in many Eucalypts. http://www.marinebio.net/marinescience/06future/olres.htm Marine Natural Resources
Marine natural resources include both biological and physical sources. Biological sources include anything attributed to life forms whereas physical sources are considered to be those things that are not part of life processes. In a few instances some resources are both biological and physical. In considering the outlook of our oceans it is important to first identify the main natural resources and their status

Biological marine natural resources include food and chemicals, as well as the living organisms themselves - including the products they secrete.

Seafood Counter

Food resources from the ocean have been taken for centuries and include mainly fish, shellfish, and plants that are used for direct consumption. Many species have been overfished in recent years particularly starting about 1970. As popular seafood species have become harder to find their price has increased until it may not be economically feasible anymore. Many popular species have become delicacies now because of this or disappeared entirely from the market.

New fisheries have opened up as older ones have become depleted - only to follow the same path as they too become depleted. For example, as the abalone fishery crashed in California in the 1970s the sea urchin fishery opened up and many abalone fishermen simply switched their catch.

Mariculture (marine aquaculture) farms sometimes try to replace and/or restore a depleted fishery. For example, in California the abalone fishery crashed (probably due to natural causes as well as overfishing) in the 1970s. This made the abalone cost between $30 and $70 per pound. During the 1960s abalone meat was similar in price to hamburger. Currently the only market abalone are produced by mariculture farms because it is illegal to fish abalone commercially in California (and there is no take at all, even by sport fishermen, in California below San Francisco). See the next lesson on Abalone for more details. Similar things have happened with other species such as salmon (see the Salmon lesson in the Water Dwellers chapter).

Kelp cutter in southern California (left). Products made with chemicals from seaweeds - algin, agar, and carrageenin (right).

Chemicals from living marine resources include drugs, and additives. Many species of marine organisms produce chemicals that have use in the drug industry. Several sponge species recently have been found to produce a cancer fighting compound. There is continued research on marine organisms from all over the world in search of new chemicals to fight diseases. Three products (agar, algin, and carrageenin) have been extracted from seaweeds for many years and used in a variety of ways. Agar is primarily used by the medical field as this is the culture medium for bacteria. Algin is used as a thickener in foods as well as a stabilizer. Carrageenin is used in many milk products as well as beer, lunch meats, pet food and toothpaste.

Most of the world 's algin used to come from California. This is where large kelp beds provide a natural source of the brown algae (a type of kelp) within which is found algin. This particular resource was harvested for over 40 years by a company (now based in Chile where there are large kelp beds). This company carefully monitors its take so that it will not deplete its resource - during its 40 years in California it has shown that it can do this without damage to the kelp beds. Recently small kelp cutters have been built to harvest kelp in California for some of the abalone mariculture farms (see lesson 6.4.2).

Aquarium in Morro Bay, California.

Aquarium store in Goleta, The Ocean Floor, (left) owned by former SBCC student. Shell shop (right) in Morro Bay (one of the best on the coast, in the author 's opinion).

Living organisms themselves are one of our newest natural resources. This includes the use of live animals in natural settings for human enjoyment like aquariums as well as the selling of live marine species in aquarium stores. This resource also includes the products that marine organisms secrete such as shells and fur. It could also include the growing industry of ecotourism where trained people take groups out into nature to view the natural life forms. Whale watching is a type of ecotourism that has replaced whaling (the killing of whales for their oil, bones and meat) in most countries (see the Whaling lesson at the end of this section).

Many aquariums, aquarium stores and shell shops are sensitive to the environmental effectstheir trade produces. A number of the larger aquariums raise their own specimens (like the Monterey Bay Aquarium in California raises most of its own jellyfish for its jellyfish displays). They also take great pains to create a natural environment for their captive species so that they live a long life. Aquarium stores often augment their living organisms with species that are raised particularly for this purpose. Shell shops often purchase their shells only from countries and suppliers who certify that the shells were taken without the living organisms inside. This is helpful in the big picture of marine ecology but is not always possible. In aquariums, aquarium stores, and shell shops there is a large amount of education that goes on with most of the people who are their clients. This education is very important in helping the public understand the importance of the health of the oceans. So, sometimes the value of education can seem to offset some of the negative impacts related to the taking of the natural marine resources used in these pursuits.

Physical marine natural resources include products from the ocean as well as the ocean itself. A few of these could also be considered partially biological.

Salt taken from the deep ocean off the big island of Hawaii at the NELHA.

Sand, gravel, and salt are physical products taken from the ocean. The sand and gravel mines are along the continental shelves in areas where these materials are present and not impacting cities. Salt is taken from seawater by several companies around the world. One example of salt extraction is now found in Hawaii at its Natural Energy Lab (see lesson 2.4.5).

Bottle water (from desalination) is a product of the deep water brought up at NELHA. The image above shows the position of their deep-sea pipeline and an inset with some of the products that result from this - including bottled water for Japan.

Ocean water itself is a natural resource and can be used to make freshwater, as a coolant or for the production of energy. Desalination plants around the world create drinkable freshwater from ocean water in areas where there are not sufficient supplies of freshwater. Ocean water is taken in by many power plants and used to cool parts of the plants. This ocean water does not leave the pipe, it just is pumped through hot areas of a power plant and the cool pipes keep the plant cool. The water leaves the plant pretty much unchanged except a few degrees higher. This is sometimes thought of as 'thermal pollution. ' Finally a process is used to take cold, deep water and turn it into energy (OTEC). This process is currently operated at NELHA in Hawaii. [Note: At NELHA a company is bottling freshwater from the deep ocean water and creating a product that is highly valued in Japan because it is from the depths of the oceans.]

Oil rig off the coast of Santa Barbara, California (left).

Oil and gas are resources that can be considered physical as well as biological. These resources are nonrenewable resources. This means that oil and gas are currently not being produced even close to the rate that they are being used. A renewable resource is one that can be used up at about the same rate that it can be replenished (such as cutting trees down but planting new ones). Oil and gas are 'fossil fuels ' - that is they are products of the bodies of organisms that died millions of years ago but did not decompose. Instead the bodies were compressed by layers of sediment (mostly under the ocean) and they changed into the petroleum products we value so much nowadays - oil and gas. Currently there just are not any areas in the ocean that we know about where the bodies of dead organisms are piling up and not decomposing. The ocean basins millions of years ago where these layers developed did not support decomposition but this has changed today.

http://marinebio.org/oceans/ocean-resources.asp
Ocean Resources
Marine Conservation Home / NEXT: Sustainable Ecotourism »
The ocean is one of Earth 's most valuable natural resources. It provides food in the form of fish and shellfish—about 200 billion pounds are caught each year. It 's used for transportation—both travel and shipping. It provides a treasured source of recreation for humans. It is mined for minerals (salt, sand, gravel, and some manganese, copper, nickel, iron, and cobalt can be found in the deep sea) and drilled for crude oil.

Oil Rig off Santa Barbara. © Wolcott Henry 2001
The ocean plays a critical role in removing carbon from the atmosphere and providing oxygen. It regulates Earth 's climate. The ocean is an increasingly important source of biomedical organisms with enormous potential for fighting disease. These are just a few examples of the importance of the ocean to life on land. Explore them in greater detail to understand why we must keep the ocean healthy for future generations.
Fishing Facts
The oceans have been fished for thousands of years and are an integral part of human society. Fish have been important to the world economy for all of these years, starting with the Viking trade of cod and then continuing with fisheries like those found in Lofoten, Europe, Italy, Portugal, Spain and India. Fisheries of today provide about 16% of the total world 's protein with higher percentages occurring in developing nations. Fisheries are still enormously important to the economy and wellbeing of communities.

Fish Market in the Philippines. © Wolcott Henry 2001
The word fisheries refers to all of the fishing activities in the ocean, whether they are to obtain fish for the commercial fishing industry, for recreation or to obtain ornamental fish or fish oil. Fishing activities resulting in fish not used for consumption are called industrial fisheries. Fisheries are usually designated to certain ecoregions like the salmon fishery in Alaska, the Eastern Pacific tuna fishery or the Lofoten island cod fishery. Due to the relative abundance of fish on the continental shelf, fisheries are usually marine and not freshwater.
Although a world total of 86 million tons of fish were captured in 2000, China 's fisheries were the most productive, capturing a whopping one third of the total. Other countries producing the most fish were Peru, Japan, the United States, Chile, Indonesia, Russia, India, Thailand, Norway and Iceland- with Peru being the most and Iceland being the least. The number of fish caught varies with the years, but appears to have leveled off at around 88 million tons per year possibly due to overfishing, economics and management practices.
Fish are caught in a variety of ways, including one-man casting nets, huge trawlers, seining, driftnetting, handlining, longlining, gillnetting and diving. The most common species making up the global fisheries are herring, cod, anchovy, flounder, tuna, shrimp, mullet, squid, crab, salmon, lobster, scallops and oyster. Mollusks and crustaceans are also widely sought. The fish that are caught are not always used for food. In fact, about 40% of fish are used for other purposes such as fishmeal to feed fish grown in captivity. For example cod, is used for consumption, but is also frozen for later use. Atlantic herring is used for canning, fishmeal and fish oil. The Atlantic menhaden is used for fishmeal and fish oil and Alaska pollock is consumed, but also used for fish paste to simulate crab. The Pacific cod has recently been used as a substitute for Atlantic cod which has been overfished.
The amount of fish available in the oceans is an ever-changing number due to the effects of both natural causes and human developments. It will be necessary to manage ocean fisheries in the coming years to make sure the number of fish caught never makes it to zero. A lack of fish greatly impacts the economy of communities dependent on the resource, as can be seen in Japan, eastern Canada, New England, Indonesia and Alaska. The anchovy fisheries off the coast of western South America have already collapsed and with numbers dropping violently from 20 million tons to 4 million tons—they may never fully recover. Other collapses include the California sardine industry, the Alaskan king crab industry and the Canadian northern cod industry. In Massachusetts alone, the cod, haddock and yellowtail flounder industries collapsed, causing an economic disaster for the area.
Due to the importance of fishing to the worldwide economy and the need for humans to understand human impacts on the environment, the academic division of fisheries science was developed. Fisheries science includes all aspects of marine biology, in addition to economics and management skills and information. Marine conservation issues like overfishing, sustainable fisheries and management of fisheries are also examined through fisheries science.
In order for there to be plenty of fish in the years ahead, fisheries will have to develop sustainable fisheries and some will have to close. Due to the constant increase in the human population, the oceans have been overfished with a resulting decline of fish crucial to the economy and communities of the world. The control of the world 's fisheries is a controversial subject, as they cannot produce enough to satisfy the demand, especially when there aren 't enough fish left to breed in healthy ecosystems. Scientists are often in the role of fisheries managers and must regulate the amount of fishing in the oceans, a position not popular with those who have to make a living fishing ever decreasing populations.
The two main questions facing fisheries management are:
1. What is the carrying capacity of the ocean? How many fish are there and how many of which type of fish should be caught to make fisheries sustainable?
2. How should fisheries resources be divided among people?
Fish populate the ocean in patches instead of being spread out throughout the enormous expanse. The photic zone is only 10-30 m deep near the coastline, a place where phytoplankton have enough solar energy to grow in abundance and fish have enough to eat. Most commercial fishing takes place in these coastal waters, as well as estuaries and the slope of theContinental Shelf. High nutrient contents from upwelling, runoff, the regeneration of nutrients and other ecological processes supply fish in these areas with the necessary requirements for life. The blue color of the water near the coastlines is the result of chlorophyll contained in aquatic plant life.
Most fish are only found in very specific habitats. Shrimp are fished in river deltas that bring large amounts of freshwater into the ocean. The areas of highest productivity known as banks are actually where the Continental Shelf extends outward towards the ocean. These include the Georges Bank near Cape Cod, the Grand Banks near Newfoundland and Browns Bank. Areas where the ocean is very shallow also contain many fish and include the middle and southern regions of the North Sea. Coastal upwelling areas can be found off of southwest Africa and off South America 's western coast. In the open ocean, tuna and other mobile species like yellowfin can be found in large amounts.
The question of how many fish there are in the ocean is a complicated one but can be simplified using populations of fish instead of individuals. The word “cohort” refers to the year the fish was born and is used to gather population statistics. Cohorts start off as eggs with an extremely high rate of mortality, which declines as the fish gets older. Juvenile fish close to the age where they can be fished are called "recruits". Cohort mortality is tied in with the species of fish due to variances in natural mortality. The biomass of a particular cohort is greatest when fish are rapidly growing and decreases as the fish get older and start to die.
Scientists use theories and models to help determine the number and size of fish populations in the ocean. Production theory is the theory that production will be highest when the number of fish does not overwhelm the environment and there are not too few for genetic diversity of populations. The maximum sustainable yield is produced when the population is of intermediate size. Yield-per-recruit theory is the quest to determine the optimum age for harvesting fish. The theory of recruitment and stock allows scientists to make a guess about the optimum population size to encourage a larger population of recruits. All of the above theories must be flexible enough to allow natural fluctuations in the fish population to occur and still gather significant data; however, the theories are limited when taking into account the effect of humans on the environment and misinformation could result in overfishing of the ocean 's resources.
Other factors that must be taken into account are the ecological requirements of individual fish species like predation and nutrition and why fish will often migrate to different areas. Water temperatures also influence the behavior of ecosystems, causing an increase in metabolism and predation or a sort of hibernation. Even the amount of turbulence in the water can affect predator-prey relationships, with more meetings between the two when waters are stirred up. Global warming could have a huge economic impact on the fisheries when fish stocks are forced to move to waters with more tolerable temperatures.
In many countries, commercial fishing has found more temporarily economical ways of catching fish, including gill nets, purse seines, and drift nets. Although fish are trapped efficiently in one day using these fishing practices, the number of fish that are wasted this way has reached 27 million tons per year, not to mention the crucial habitats destroyed that are essential for the regeneration of fish stocks. In addition, marine mammals and birds are also caught in these nets. The wasted fish and marine life is referred to as bycatch, an unfortunate side-effect of unsustainable fishing practices that can turn the ecosystem upside-down and leave huge amounts of dead matter in the water. Other human activities like trawling and dredging of the ocean floor have bulldozed over entire underwater habitats. The oyster habitat has been completely destroyed in many areas from the use of the oyster patent tong and sediment buildup draining from farm runoff.
Shipping
The word “shipping” refers to the activity of moving cargo with ships in between seaports. Wind-powered ships exist, but more often ships are powered by steam turbine plants or diesel engines. Naval ships are usually responsible for transporting most of trade from one country to another and are called merchant navies. The various types of ships include container ships, tankers, crude oil ships, product ships, chemical ships, bulk carriers, cable layers, general cargo ships, offshore supply vessels, dynamically-positioned ships, ferries, gas and car carriers, tugboats, barges and dredgers.

In theory, shipping can have a low impact on the environment. It is safe and profitable for economies around the world. However, serious problems occur with the shipping of oil, dumping of waste water into the ocean, chemical accidents at sea, and the inevitable air and water pollution occuring when modern day engines are used. Ships release air pollutants in the form of sulphur dioxide, nitrogen oxides, carbon dioxide, hydrocarbons and carbon monoxide. Chemicals dumped in the ocean from ships include chemicals from the ship itself, cleaning chemicals for machine parts, and cleaning supplies for living quarters. Large amounts of chemicals are often spilled into the ocean and sewage is not always treated properly or treated at all. Alien species riding in the ballast water of ships arrive in great numbers to crash native ecosystems and garbage is dumped over the side of many vessels. Dangerous industrial waste and harmful substances like halogenated hydrocarbons, water treatment chemicals, and antifouling paints are also dumped frequently. Ships and other watercraft with engines disturb the natural environment with loud noises, large waves, frequently striking and killing animals like manatees and dolphins.
Tourism
Tourism is the fastest growing division of the world economy and is responsible for more than 200 million jobs all over the world. In the US alone, tourism resulted in an economic gain of 478 billion dollars. With 700 million people traveling to another country in the year 2000, tourism is in the top five economic contributors to 83% of all countries and the most important economy for 38% of countries. The tourism industry is based on natural resources present in each country and usually negatively affect ecosystems because it is often left unmanaged. However, sustainable tourism can actually promote conservation of the environment.

Dive boat with recreational divers, Key Largo, Florida. © Wolcott Henry 2001
The negative effects of tourism originate from the development of coastal habitats and the annihilation of entire ecosystems like mangroves, coral reefs, wetlands and estuaries. Garbage and sewage generated by visitors can add to the already existing solid waste and garbage disposal issues present in many communities. Often visitors produce more waste than locals, and much of it ends up as untreated sewage dumped in the ocean. The ecosystem must cope with eutrophication, or the loss of oxygen in the water due to excessive algal bloom, as well as disease epidemics. Sewage can be used as reclaimed water to treat lawns so that fertilizers and pesticides do not seep into the ocean.
Other problems with tourism include the overexploitation of local seafood, the destruction of local habitats through careless scuba diving or snorkeling and the dropping of anchors on underwater features. Ecotourism and cultural tourism are a new trend that favors low impact tourism and fosters a respect for local cultures and ecosystems.
Mining
Humans began to mine the ocean floor for diamonds, gold, silver, metal ores like manganese nodules and gravel mines in the 1950 's when the company Tidal Diamonds was established by Sam Collins. Diamonds are found in greater number and quality in the ocean than on land, but are much harder to mine. When diamonds are mined, the ocean floor is dredged to bring it up to the boat and sift through the sediment for valuable gems. The process is difficult as sediment is not easy to bring up to the surface, but will probably become a huge industry once technology evolves to solve the logistical problem.
Metal compounds, gravels, sands and gas hydrates are also mined in the ocean. Mining of manganese nodules containing nickel, copper and cobalt began in the 1960 's and soon after it was discovered that Papua New Guinea was one of the few places where nodules were located in shallow waters rather than deep waters. Although manganese nodules could be found in shallow waters in significant quantities, the expense of bringing the ore up to the surface proved to be expensive. Sands and gravels are often mined for in the United States and are used to protect beaches and reduce the effects of erosion.
Mining the ocean can be devastating to the natural ecosystems. Dredging of any kind pulls up the ocean floor resulting in widespread destruction of marine animal habitats, as well as wiping out vast numbers of fishes and invertebrates. When the ocean floor is mined, a cloud of sediment rises up in the water, interfering with photosynthetic processes of phytoplankton and other marine life, in addition to introducing previously benign heavy metals into the food chain. As minerals found on land are exploited and used up, mining of the ocean floor will increase.
Climate Buffer
The ocean is an integral component of the world 's climate due to its capacity to collect, drive and mix water, heat, and carbon dioxide. The ocean can hold and circulate more water, heat and carbon dioxide than the atmosphere although the components of the Earth 's climate are constantly exchanged. Because the ocean can store so much heat, seasons occur later than they would and air above the ocean is warmed. Heat energy stored in the ocean in one season will affect the climate almost an entire season later. The ocean and the atmosphere work together to form complex weather phenomena like the North Atlantic Oscillation and El Niño. The many chemical cycles occurring between the ocean and the atmosphere also influence the climate by controlling the amount of radiation released into ecosystems and our environment.
The atmosphere directly above the ocean does not absorb much heat by itself, so in order for it to warm up, the temperature of the ocean has to rise first. The two other ways for the atmosphere to warm near the ocean are by reflection of light off of the surface of the ocean or by the evaporation of water from the ocean surface. The temperature of the ocean controls the climate in the lower part of the atmosphere, so for most areas of the Earth the ocean temperature is responsible for the air temperature.
The main forms of climate buffering by the ocean are by the transport of heat through ocean currents traveling across huge basins. Areas like the tropics end up being cooled and higher latitudes are warmed by this effect. Air temperatures worldwide are regulated by the circulation of heat by the oceans. The ocean stores heat in the upper two meters of the photic zone. This is possible because seawater has a very high density and specific heat and can store vast quantities of energy in the form of heat. The ocean can then buffer changes in temperature by storing heat and releasing heat. Evaporation cools ocean water which cools the atmosphere. It is most noticeable near the equator and the effect decreases closer to the poles.
Oxygen Production
Gases in the atmosphere like carbon, nitrogen, sulfur and oxygen are dissolved through the water cycle. The gases that are now crucial to all ecosystems and biological processes originally came from the inside layers of the earth during the period when the earth was first formed. The rate of flow for oxygen as well as other gases is controlled by biological processes, especially metabolism of organisms like prokaryotes and bacteria. Prokaryotes have been around since the beginning of the Earth, have evolved to be able to use chemical energy to create organic matter and are capable of both reducing and oxidizing inorganic compounds. Bacteria that can reduce inorganic compounds are anaerobic and those that oxidize inorganic compounds are aerobic. Aerobic bacteria release oxygen as a by-product of photosynthesis.
Approximately two billion years ago, aerobic bacteria began producing oxygen which gradually filled up all of the oxygen reservoirs in the environment. Once these “sinks” were filled, molecular oxygen began to build in the atmosphere, creating an environment favorable for other life to inhabit the Earth. Sinks included reduced iron ions and hydrogen sulfide gas. Evidence of this process can be found in the banded iron formations created when iron minerals were precipitated. The oxygen started to fill the atmosphere up and new bacteria evolved that could use oxygen to oxidize both inorganic and organic compounds. Bacteria that were accustomed to an oxygen-poor atmosphere only survived in anaerobic environments like sewage, swamps, and in the sediments of both marine and freshwater areas.
Phytoplankton account for possibly 90% of the world 's oxygen production because water covers about 70% of the Earth and phytoplankton are abundant in the photic zone of the surface layers. Some of the oxygen produced by phytoplankton is absorbed by the ocean, but most flows into the atmosphere where it becomes available for oxygen dependent life forms.
References
Wikipedia: Fisheries
Wikipedia: Shipping
U.S. Global Change Research Information Office - How Bountiful are Ocean Fisheries? by Brian J. Rothschild
United Nations Atlas of the Oceans
GESAMP on environmental aspects of tourism 'The world 's biggest industry ever — but poorly managed for the environment '
Oceanlink | Oceanmatters: Undersea Mining
WHOI : Oceanus : Ocean Resources
Department of Earth and Environmental Sciences at Columbia University
Global Marine Oil Pollution Information Gateway • Facts • SHIPPING - NOT JUST OIL POLLUTION

http://marinebio.org/oceans/history-of-marine-biology.asp
A History of the Study of Marine Biology
Marine Life / The Naming of Life: Marine Taxonomy »
The history of marine biology may have begun as early as 1200 BC when the Phoenicians began ocean voyages using celestial navigation. References to the sea and its mysteries abound in Greek mythology, particularly the Homeric poems "The Iliad" and "The Odyssey". However, these two sources of ancient history mostly refer to the sea as a means of transportation and food source.
It wasn 't until the writings of Aristotle from 384-322 BC that specific references to marine life were recorded. Aristotle identified a variety of species including crustaceans, echinoderms, mollusks, and fish. He also recognized that cetaceans are mammals, and that marine vertebrates are either oviparous (producing eggs that hatch outside the body) or viviparous (producing eggs that hatch within the body). Because he is the first to record observations on marine life, Aristotle is often referred to as the father of marine biology.
The Early Expeditions
The modern day study of marine biology began with the exploration by Captain James Cook (1728-1779) in 18th century Britain. Captain Cook is most known for his extensive voyages of discovery for the British Navy, mapping much of the world 's uncharted waters during that time. He circumnavigated the world twice during his lifetime, during which he logged descriptions of numerous plants and animals then unknown to most of mankind. Following Cook 's explorations, a number of scientists began a closer study of marine life including Charles Darwin (1809-1882) who, although he is best known for the Theory of Evolution, contributed significantly to the early study of marine biology. His expeditions as the resident naturalist aboard theHMS Beagle from 1831 to 1836 were spent collecting and studying specimens from a number of marine organisms that were sent to the British Museum for cataloguing. His interest in geology gave rise to his study of coral reefs and their formation. His experience on the HMS Beagle helped Darwin formulate his theories of natural selection and evolution based on the similarities he found in species specimens and fossils he discovered in the same geographic region.
The voyages of the HMS Beagle were followed by a 3-year voyage by the British ship HMSChallenger led by Sir Charles Wyville Thomson (1830-1882) to all the oceans of the world during which thousands of marine specimens were collected and analyzed. This voyage is often referred to as the birth of oceanography. The data collected during this trip filled 50 volumes and served as the basis for the study of marine biology across many disciplines for many years. Deep sea exploration was a benchmark of the Challenger 's voyage disproving British explorer Edward Forbes ' theory that marine life could not exist below about 550 m or 1,800 feet.
The Challenger was well equipped to explore deeper than previous expeditions with laboratories aboard stocked with tools and materials, microscopes, chemistry supplies, trawls and dredges, thermometers, devices to collect specimens from the deep sea, and miles of rope and hemp used to reach the ocean depths. The end product of the Challenger 's voyage was almost 30,000 pages of oceanographic information compiled by a number of scientists from a wide range of disciplines. The "Report of the Scientific Results of the Exploring Voyage of H.M.S. Challenger during the years 1873-76" reported, in addition to the fact that life does exist below 550 m/1,800 feet, findings such as:
4,717 new species;
The first systematic plot of currents and temperatures in the ocean;
A map of bottom deposits much of which has remained current to the present;
An outline of the main contours of the ocean basins; and
The discovery of the mid-Atlantic Ridge.
The report is an important work still used by scientists today. In addition to the report, Sir Thomson also wrote a book about the voyage in 1877 titled "The Voyage of the Challenger." He also wrote one of the early marine biology textbooks"The Depths of the Sea" in 1877.
The Institutions
These expeditions were soon followed by marine laboratories established to study marine life. The oldest marine station in the world, Station Biologique de Roscoffwas established in Concarneau, France founded by the College of France in 1859. Concarneau is located on the northwest coast of France. The station was originally established for the cultivation of marine species, such as Dover sole, because of its location near marine estuaries with a variety of marine life. Today, research is conducted on molecular biology, biochemistry, and environmental studies.
In 1871, Spencer Fullerton Baird, the first director of the US Commission of Fish and Fisheries (now known as theNational Marine Fisheries Service), began a collection station in Woods Hole, Massachusetts because of the abundant marine life there and to investigate declining fish stocks. This laboratory still exists now known as the Northeast Fisheries Science Center, and is the oldest fisheries research facility in the world. Also at Woods Hole, the Marine Biological Laboratory (MBL) was established in 1888 by Alpheus Hyatt, a student of Harvard naturalist Louis Agassiz who had established the first seaside school of natural history on an island near Woods Hole. MBL was designed as a summer program for the study of the biology of marine life for the purpose of basic research and education. The Woods Hole Oceanographic Institute was created in 1930 in response to the National Academy of Science 's call for "the share of the United States of America in a worldwide program of oceanographic research" and was funded by a $3 million grant by the Rockefeller Foundation.
An independent biological laboratory was established in San Diego in 1903 by University of California professor Dr. William E. Ritter, which became part of the University of California in 1912 and was named the Scripps Institution of Oceanography after its benefactors. Scripps has since become one of the world 's leading institutions offering a multi-disciplinary study of oceanography.
Exploration of the Deep Sea
Technology brought the study of marine biology to new heights during the years following the HMS Challenger expedition. In 1934 William Beebe (1877-1962) and Otis Barton descended 923 m/3,028 ft below the surface off the coast of Bermuda in a bathysphere designed and funded by Barton. This depth record was not broken until 1948 when Barton made a bathysphere dive to 1,372 m/4,500 ft. During the interim, Beebe was able to observe deep sea life in its own environment rather than in a specimen jar. Although he was criticized for failing to publish results in professional journals, his vivid descriptions of the bathysphere dives in the books he published inspired some of today 's greatest oceanographers and marine biologists.
In 1960, a descent was made to 10,916 m/35,813 ft in the Challenger Deep of the Marianna trench—the deepest known point in the oceans, 10,924 m/35,838 ft deep at its maximum, near 11° 22 'N 142° 36 'E—about 200 miles southwest of Guam. The dive was made in the bathyscape Trieste built by Auguste Piccard, his son Swiss explorer Jean Ernest-Jean Piccard and U.S. Navy Lieutenant Don Walsh. The descent took almost five hours and the two men spent barely twenty minutes on the ocean floor before undertaking the 3 hour 15 minute ascent.
The Trieste 's first dive was made in 1953. In the years following, the bathyscape was used for a number of oceanographic research projects, including biological observation, and in 1957 she was chartered and later purchased by the U.S. Navy. The Navy continued to use the bathyscape for oceanographic research off the coast of San Diego, and later used the Trieste for a submarine recovery mission off the U.S. east coast. The bathyscape was retired following the U.S. Navy 's commission of the Trieste II, and is currently on exhibit at the Washington Naval Historical Center.
The Scientists
Rachel Carson (1907-1964) was a scientist and writer who brought the wonders of the sea to people with her lyrical writings and observations about the sea. Although she was a biologist for the US Fish and Wildlife Service, she devoted her spare time to translating science into writings that would infect the reader with her sense of wonder and respect for nature. She published an article in Atlantic Monthly in 1937 titled "Undersea" which was followed by a book in 1941 titled "Under the Sea-Wind." These publications described the sea and the life within it from a scientist 's point of view, but in the words of a naturalist. In 1951, she published "The Sea Around Us" a prize-winning bestseller on the history of the sea. The success of this book allowed her to resign from federal service and write full-time. Shortly after, her focus turned to the negative impact of pesticides, a cause to which she remained devoted to by fighting to raise public awareness until her death in 1964.
Inspired by the work of William Beebe, Dr. Sylvia Earle (1935-) began her work as an oceanographer at the tender age of 3 when she was knocked off her feet by a wave. She was fascinated by the ocean and its creatures at a very early age growing up near the shore in New Jersey and later in Florida on the Gulf of Mexico. She began her studies with marine botany based on her belief that vegetation is the foundation of any ecosystem. Although she struggled to balance her studies and starting a family, Earle earned her PhD from Duke University, becoming well known in the marine science community for her detailed studies of aquatic life. Early in her career, and while she was four months pregnant, Earle traveled 30.5 m/100 ft below the surface in a submersible. This was the first of many submersible dives she would make during her career. Her experience living in an underwater marine habitat earned her celebrity status in the scientific community. In 1969, the Smithsonian Institute released a call for proposals that was circulated in the marine science community for those interested in conducting research while living in an underwater habitat. Earle submitted a proposal describing her intention to use the opportunity to study the ecology of marine plants and fishes in great detail by combining her observations with those of the ichthyologists on board. Unfortunately, the other applicants were male, and the review board deemed Earle 's cohabitation with them inappropriate. Her request to be a part of the Tektite I mission was rejected; however, the Smithsonian later proposed an all-female Tektite II mission which Earle became a part of. The Tektite II mission received a lot of attention at the time (1970) because of its all female crew.
Following her experience aboard the underwater habitat, Earle developed an interest in deep sea exploration, and in 1979 she broke the record for deep diving at 381 m/1,250 ft below the surface in a special suit called the Jim suitdesigned to withstand the pressure. Her record has not been broken. Earle decided to test the Jim suit as part of her research on a book published by National Geographic "Exploring the Deep Frontier", and out of her frustration that scuba diving techniques only scratched the surface of the ocean. Following this adventure, Earle started two companies that manufacture deep sea exploration vehicles. The continued advancements in the the technology of these vehicles has helped open up areas in the deep sea previously unexplored. During the 1990s, Earle served as Chief Scientist for theNational Oceanic and Atmospheric Administration (NOAA). She is currently an Explorer-in-Residence with National Geographic, and, in addition to her research, remains committed to raising awareness on marine environmental issues.
Dr. Robert Ballard (1942-), also a deep-sea explorer, may be best known for finding the Titanic using technologies he helped to develop, including the Argo/Jason remotely operated vehicles and the technology that transmits video images from the deep sea. His earlier deep sea explorations led to the first discovery of hydrothermal vents during an exploration in a manned submersible of the Mid-Ocean Ridge. Ballard founded theWoods Hole Oceanographic Institution 's Deep Submergence Laboratory and spent 30 years there working on the use of manned submersibles. Ballard has devoted a great deal of time to furthering the field of deep sea exploration. He created a distance-learning program with more than one million students enrolled, taught by more than 30,000 science teachers worldwide. He also founded the Institute for Explorationlocated in Mystic, Connecticut for the study of deep-water archaeology which led to the discovery of the largest number of ancient ships ever found in the deep sea. Currently, he is a National Geographic Society Explorer-in-Residence Professor of Oceanography at the University of Rhode Island 's Graduate School of Oceanography, and Director of theInstitute for Archaeological Oceanography.
The Explorers
The advent of scuba diving introduced other pioneers to the study of marine biology. Jacques Cousteau (1910-1997) was determined to safely breathe compressed air underwater in order to lenghthen dive times. His work with Emile Gagnan ultimately led to the invention of the regulator which releases compressed air to divers "on demand" (as opposed to a continuous flow). The combination of the Cousteau-Gagnan regulator with compressed air tanks allowed Cousteau the freedom to film underwater, and by 1950 he had produced the Academy Award winning "The Silent World." By the 1970s he was bringing the underwater realm into millions of homes with his PBS series "Cousteau Odyssey."Cousteau 's television documentaries won 40 Emmy Awards. Like other oceanography pioneers, Cousteau was criticized for his lack of scientific credentials, however his legacy fostered a greater knowledge and understanding of the devastation caused by threats to ocean health such as pollution of marine resources and resource exploitation.
Cousteau 's Austrian counterpart, Dr. Hans Hass (1919-), also helped introduce the wonders of the underwater world to the public. Hass and his wife Lotte were both passionate about underwater exploration and protection of the marine environment, and together they produced numerous documentaries and wrote a variety of books on their underwater experiences. During his career as an underwater explorer, Hass also made significant contributions to diving technology. He invented one of the first underwater flash cameras and contributed to the development of the Drager oxygen rebreather which he and Lotte used in 1942 to film "Men Amongst Sharks" and continued to use on diving expeditions aboard their research vessel "Xarifa" in the Red Sea and Caribbean. Hass is also known as one of the first humans to interact with a sperm whale underwater which helped him become a pioneer in the study of marine animal behavior.
The Future
Today, the possibilities for ocean exploration are nearly infinite. In addition to scuba diving, rebreathers, fast computers, remotely-operated vehicles (ROVs), deep sea submersibles, reinforced diving suits, and satellites, other technologies are also being developed. But interdisciplinary research is needed to continue building our understanding of the ocean, and what needs to be done to protect it. In spite of ongoing technological advances, it is estimated that only 5% of the oceans have been explored. Surprisingly, we know more about the moon than we do the ocean. This needs to change if we are to ensure the longevity of the life in the seas—and they cover 71% of the earth 's surface. Unlike the moon, they are our backyard. Without a detailed collective understanding of the ramifications of pollution, overfishing, coastal development, as well as the long-term sustainability of ocean oxygen production and carbon dioxide and monoxide absorption, we face great risks to environmental and human health. We need this research so that we can act on potential problems—not react to them when it is already too late.
Fortunately, thanks to the work of past and present ocean explorers, the public is increasingly aware of these risks which encourage public agencies to take action and promote research. The efforts of public agencies using a multi-disciplinary approach, together with the efforts provided by numerous private marine conservation organizations that work on issues such as advocacy, education, and research, will help drive the momentum needed to face the challenges of preserving the ocean.
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