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
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 ecosystem’s primary productivity is most limited and affected by the amount of nutrients in the ecosystem. According to the Biodiversity and Climate Research Center, aquatic ecosystems are some of the most heavily altered ecosystems. Several stressors account for their loss in biodiversity including: nutrient enrichment, contaminant pollution, and sedimentation alterations (Sunderman et, al 2013). Other existing knowledge from the Journal of the North American Benthological Society suggests that first order streams are neither Nitrogen limited nor Nitrogen retentive (Grimm 2005). Another article published in the Journal of the North American Benthological Society has concluded that geomorphic structures in Nitrogen-rich streams wouls also tend to support higher rates of nitrification than those streams in a forested reference area, providing support for the fact that theses structures can become sources of NO3- (Groffman et al 2005). For this experiment, the experimenter will investigate the different chemical and physical properties of four sites on a stream. Properties that will be investigated include: the velocity, discharge, temperature, dissolved oxygen, nutrients, pH, and amount of benthic invertebrates. Some questions to be asked will be, “Is there a relationship between the velocity and nutrients present in the ecosystem? Is there a correlation between the amount of dissolved oxygen in the system and the pH?” Some hypotheses that could be tested during this experiment include: “If the temperature in the system increases, then the amount of individuals found will also increase.” Another would be, “The higher the discharge of the stream, the less nutrients will be present in the system.” Another testable hypothesis is, “The more benthic autotrophs present, the higher the dissolved oxygen will be in the stream.” One more hypothesis that could be tested is, “If the velocity of the stream is higher, then there will be less benthic invertebrates present.” Through experimentation and gathering data from the stream these hypotheses will be viable for testing.
For this experiment, the lab group worked south of the University of Denver at a first order stream that flows through DeBoer Park. The stream is located on the corner of E Harvard Avenue and York St in Denver, CO 80210. The stream, Harvard Gulch, lies at 39.67 degrees North latitude and -104.96 degrees West longitude. The elevation at this location is 5,343 feet (Topographic). Each group collected data from the Harvard Gulch from 2:30PM-3:30PM on September 23, 2013. The weather was fairly warm, it was sunny with only a slight breeze.
The group began by surveying the stream and determining four points on the river, (1) the rocky intake (just west of the University Ave. 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...
Cited: DiVenere, V., Stream Processes. Retrieved from Lecture Notes Online Web Site: http://www.columbia.edu/~vjd1/streams_basic.htm
Grimm, N.B., Sheibley, R.W., Crenshaw, C.L., Dahm, C.N., Roach, W.J., Zeglin, L.H., 2005
Groffman, P. M., Dorsey, A.M., Mayer, P.M., 2005. N processing within geomorphic structures in urban streams. Journal of the North American Benthological Society. 24:613-625.
Sunderman, A., Gerhardt, M., Kappes, H., Haase, P., 2013
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