Stream Ecology Lab

Experiment 3
Stream Ecology: Examining the Physiochemical and Biological Processes of a Stream

Jaclynn D Dame
Date Performed: 09/23/2013
Date Submitted: 09/30/2013

University of Denver
2199 S University Blvd Denver, CO 80210
Introduction:
The purpose of this experiment is to understand the physiochemical and biological processes of a stream by observing a lotic stream (moving stream). In observing the stream will come a better understanding of how the chemical and physical properties of a stream interrelate and correlate. In undertaking this study the experimenter will build upon the concepts of aquatic ecology that we have learned in class. It will build upon concepts such as the fact that aquatic
Bridge), (2) the largest poo, (3) a quickest riffle, and (4) the smooth cement outflow at the west end of the park. Each group was assigned one of the sites. The first task required each group to measure out 5m at the assigned site with a tape measure and mark off the boundaries with flags. Then the group measured the velocity of the stream at that site by placing a bottle in the center of the stream and timing, with a stopwatch, how long it took for the bottle to go 5m. Repeat this three times. Next up was finding the discharge. The group marked off 6 different points within the 5m boundary in 1m increments. The depth was measure at each of these 1m increments at a width of ¼,1/2, and ¾ the distance from one side of the stream to the other. The group summed the discharges for each 1m section to obtain the total stream discharge. Next the group found the pH of the water by using the Vernier LabQuest and pH probe. The stream water temperature was calculated next. In order to take the temperature, the Vernier LabQuest and temperature probe were used. The temperature was taken at the surface of the stream and 1cm from the bottom. Dissolved oxygen was then found with the DO Chemets Kit. The group repeated this 3 times. A sample of lotic water was taken as well as benthic organisms. When the group returned from lab the Nitrogen and Phosphorous
The only site that this did not hold true for was the pool. The average discharge may have been lower here compared to its velocity because in the pool there is typically a lower velocity and it has the greatest depth. Because the depth was so large it could have decreased the amount of discharge. The discharge of the stream overall could have been relatively low because width, depth, and velocity of streams increases the closer they get to a large river (“Water” 2004). According to the lab data the riffle was supposed to have the greatest velocity, however the Outflow exhibited the highest velocity. This could have been due to different groups putting the bottle into the water at different spots. The group who did the riffle could have put their bottle closer to the stream bed and the outflow more in the middle of the stream. This is supported by Columbia University, they say that the greatest stream velocity is found in the midstream near the surface and slowest near the stream bed due to friction (DiVenere 2013). The intake and riffle both had a lower pH compared to the pool and outflow. This correlated with amount of dissolved oxygen. Therefore, it can be said that the pH has an affect on the amount of dissolved oxygen in the stream. The pH was chosen as the most important part of the chemistry table