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<br />Organic matter <br /> <br />Benthic organic matter biomass should be collected as' part of quantitative zoobenthos <br /> <br />samples. Once the invertebrateS have been removed from a sample the sample should be divided <br /> <br />into coarse (<1 mm) and fine (0.250-1.0 mm) particulate Size fractions. This material should be <br /> <br />then dried at 60 C until a constant weight is attained, weighed, and fired in a mufile furnace at 550 <br /> <br />C for 2 hours to obtain ash-free dry weight. <br /> <br />Primary Production <br /> <br /> <br />In the laboratory, periphyton samples should be thawed and the water extracted by vacuum <br /> <br />over a glass fiber filter. The filter should then be cut in half. One-half to be used to determine <br /> <br /> <br />chlorophyU a and the half to determine biomass. Chlorophyll a concentration should be <br /> <br /> <br />determined using standard methods. Biomass should be determined as described above for <br /> <br /> <br />benthic organic matter. <br /> <br />Data Analysis <br />The goal of initial data analysis should be to evaluate the adequacy of sampling program. In <br />other words, are the number of reaches being ,sampled, the number of samples being collected, <br />and the level of taxonomy adequate to detect subtle changes in invertebrate communities or is the <br />data primarialy a general description and a baseline for detecting gross changes. The objective is <br />to collect data that will allow for the detection of subtle changes in invertebrate populations in <br />response to differing hydrologic regimes. <br />An additonal objective of this project is to identify invertebrate taxa that can be used as <br /> <br />10 <br />