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invertebrates, is filtered through a 63-µm screen. Larger sediment particles that <br />remained in the plastic tray were periodically examined and then discarded. We placed <br />the material collected in the 63-µm screen in 70% ETOH for storage. <br />Sample Sorting <br />The samples sorted were randomly chosen from the fifty samples taken at each <br />site and date. Each sample was placed in glass petri dishes and sorted with the aid of <br />a dissecting microscope (see Tables 1-4 for number of samples processed). Four major <br />taxa ( Nematoda, Oligochaeta, Ceratopagonidae and Chironomidae,) were counted. Only <br />Chironomidae were identified to the generic level. Rare taxa were also encountered but <br />were not quantified (see Table 5). <br />The number of samples we sorted from each site and sampling date was <br />determined in the following way. Five of the fifty samples were randomly selected and <br />the four major taxa were counted. Because of their obvious contagious distribution, <br />numbers of each taxa were then log transformed (x+l). The variance and mean were <br />used in the following formula (Elliot 1977): <br />SZ <br />N= <br />d2X-2 <br />Where, N=the number of samples to process, S=the variance, D=the level of <br />confidence (in this case .1), and x=the mean. If, after five samples were processed, N <br />was less than five for any of the taxa, picking for that group ceased. Those taxa where <br />N was greater than five were counted in another sample. The mean and variance for taxa <br />not eliminated were calculated again and used in the formula. This process continued <br />7