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The Effects of Sodium Arsenite and Silvex on the Plankton Populations in Farm Ponds
Author(s) -
Cowell Bruce C.
Publication year - 1965
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1965)94[371:teosaa]2.0.co;2
Subject(s) - zooplankton , copepod , plankton , sodium arsenite , phytoplankton , environmental science , biology , toxicology , zoology , ecology , chemistry , nutrient , arsenic , organic chemistry , crustacean
A method of constructing polyethylene barriers which effectively divided a pond into two similar areas is described. With this technique, replications of treatment plots and control plots can be made in the same pond, thereby eliminating the problem of variability among ponds. A relatively new test statistic, sequential analysis, was adapted for research in aquatic weed control. This test statistic is extremely valuable in that it eliminates the necessity of pre‐treatment sampling. Valid conclusions can be obtained more rapidly, and a larger number of experiments can be conducted during one season. Neither herbicide had any effect on the phytoplankton, and silvex was neither toxic nor inhibitory to zooplankton at concentrations of 2 ppm. Applications of 4 ppm sodium arsenite produced drastic reductions in zooplankton. Differences of between one and two orders of magnitude were observed when samples of rotifers from areas treated with sodium arsenite were compared with those from control of silvex‐treated areas of the same pond. Similar comparisons of copepod‐cladoceran samples showed differences which ranged from sevenfold to one order of magnitude. Such differences were not observed in any of the ponds where two control areas (untreated) were compared or where a control area and a silvex‐treated area were compared.