Coastal Upwelling Case Study
1) What is a gyre? How many currents exist within each gyre? Name the five subtropical gyres, and identify the primary surface currents that comprise each gyre?
A gyre is large system of rotating ocean currents, which dominates the surfaces of the ocean. Five subtropical gyres are the following:
• North Pacific
• South Pacific
• North Atlantic
• South Atlantic
• Indian Ocean
2) Describe the process of coastal upwelling. Why is an abundance of marine life associated with these areas?
The process known as coastal upwelling occurs when winds blow toward the equator and parallel to the coast. Because of the Coriolis Effect, the surface water moves away from the shore area and is replaced by cold water from below. An example of coastal upwelling is the colder ocean …show more content…
temperatures along the California coast as compared to the east coast of the United States. Upwelling also brings nutrient rich water to the surface thus attracting marine life to the area.
3) In what direction is longshore transport occurring in figure 10.22? Is it toward the top left or toward the bottom right of the photo?
In the figure 10.22 of the text, the sand seems to be accumulated on the right side of the groins, which means that the longshore current is transporting sand right to left (toward the top left of the figure).
4) Relate the damming of rivers to the shrinking of beaches at some locations along the west coast of the United States.
Along the West Coast, much of the sand found on beaches originates as clastic sediment in streams and rivers that discharge into the sea. Damming these streams traps the sand behind the dam and reduces the input of new sand to the beach system. With reduced input, not enough of the sand lost to offshore areas is being replaced; thus the beach is starved and narrowed by erosion. Narrowed beaches allow storm waves to directly impact a sea cliff with minimal loss of energy, thus accelerating its erosional retreat.
Reservoirs trap the sand that would otherwise nourish the beach environment.
5) Describe the processes that affect seawater salinity. For each process, indicate whether water is added or removed and if it decreases or increases salinity. What physical conditions create high-salinity water in the Red Sea and low-salinity in the Baltic
Sea?
The processes responsible to add large amounts of freshwater to seawater include precipitation, runoff from land, and melting of icebergs, and sea ice. Whenever fresh water is added to the sea, the seawater decreases its salinity. In the other hand, the processes that remove large amounts of freshwater from seawater, including evaporation and formation of sea ice; have the effect of increasing salinity.
Restricted waters with high evaporation rates result in high-salinity water in the Red Sea, whereas the influx of large quantities of freshwater from rivers and precipitation result in low-salinity water in the Baltic Sea.
6) Why are seafloor sediments useful in studying climates of the past?
Most seafloor sediments contain the remains of organisms that once lived near the sea surface. Since the numbers and types of organisms living near the sea surface vary as climate (especially temperature) fluctuates, sea-floor sediments hold important clues to changes in climate through time.
A gyre is large system of rotating ocean currents, which dominates the surfaces of the ocean. Five subtropical gyres are the following:
• North Pacific
• South Pacific
• North Atlantic
• South Atlantic
• Indian Ocean
2) Describe the process of coastal upwelling. Why is an abundance of marine life associated with these areas?
The process known as coastal upwelling occurs when winds blow toward the equator and parallel to the coast. Because of the Coriolis Effect, the surface water moves away from the shore area and is replaced by cold water from below. An example of coastal upwelling is the colder ocean …show more content…
temperatures along the California coast as compared to the east coast of the United States. Upwelling also brings nutrient rich water to the surface thus attracting marine life to the area.
3) In what direction is longshore transport occurring in figure 10.22? Is it toward the top left or toward the bottom right of the photo?
In the figure 10.22 of the text, the sand seems to be accumulated on the right side of the groins, which means that the longshore current is transporting sand right to left (toward the top left of the figure).
4) Relate the damming of rivers to the shrinking of beaches at some locations along the west coast of the United States.
Along the West Coast, much of the sand found on beaches originates as clastic sediment in streams and rivers that discharge into the sea. Damming these streams traps the sand behind the dam and reduces the input of new sand to the beach system. With reduced input, not enough of the sand lost to offshore areas is being replaced; thus the beach is starved and narrowed by erosion. Narrowed beaches allow storm waves to directly impact a sea cliff with minimal loss of energy, thus accelerating its erosional retreat.
Reservoirs trap the sand that would otherwise nourish the beach environment.
5) Describe the processes that affect seawater salinity. For each process, indicate whether water is added or removed and if it decreases or increases salinity. What physical conditions create high-salinity water in the Red Sea and low-salinity in the Baltic
Sea?
The processes responsible to add large amounts of freshwater to seawater include precipitation, runoff from land, and melting of icebergs, and sea ice. Whenever fresh water is added to the sea, the seawater decreases its salinity. In the other hand, the processes that remove large amounts of freshwater from seawater, including evaporation and formation of sea ice; have the effect of increasing salinity.
Restricted waters with high evaporation rates result in high-salinity water in the Red Sea, whereas the influx of large quantities of freshwater from rivers and precipitation result in low-salinity water in the Baltic Sea.
6) Why are seafloor sediments useful in studying climates of the past?
Most seafloor sediments contain the remains of organisms that once lived near the sea surface. Since the numbers and types of organisms living near the sea surface vary as climate (especially temperature) fluctuates, sea-floor sediments hold important clues to changes in climate through time.