STP865

    Effects of Atrazine on Community Level Responses in Taub Microcosms

    Published: Jan 1985


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    Abstract

    As part of a study to evaluate laboratory toxicity screening tests that include single species bioassays and microcosms, we examined community level responses in Taub microcosms exposed to atrazine (60, 100, 200, 500, 1000, and 5000 µg/L), a commonly used herbicide. Measurements of community metabolism included primary productivity, community respiration, primary production efficiency, and productivity/respiration (Pn/Rni) ratios. These community measurements varied in their sensitivity to atrazine. Primary production efficiency (primary productivity per unit chlorophyll) appeared to be the most sensitive measurement with greatly reduced efficiencies occurring throughout the experiment at atrazine exposure of 60 µg/L. The other community measures appeared to be more sensitive to atrazine during the interval when) ratios. These community measurements varied in their sensitivity to atrazine. Primary production efficiency (primary productivity per unit chlorophyll) appeared to be the most sensitive measurement with greatly reduced efficiencies occurring throughout the experiment at atrazine exposure of 60 µg/L. The other community measures appeared to be more sensitive to atrazine during the interval when Daphnia magna populations were highest, suggesting increased pressure by D. magna on primary producers increased the sensitivity of this test system to atrazine. All community metabolism measurements of the microcosms exposed to higher atrazine concentrations of 500, 1000, and 5000 µg/L differed from controls throughout the experiment.

    Keywords:

    aquatic ecosystems, microcosm, atrazine, community metabolism, productivity/respiration ratios, primary productivity, respiration


    Author Information:

    Stay, FS
    Research aquatic biologist, supervisory research aquatic biologist, and aquatic biologist, Corvallis Environmental Research Laboratory, U. S. Environmental protection Agency, Corvallis, OR

    Larsen, DP
    Research aquatic biologist, supervisory research aquatic biologist, and aquatic biologist, Corvallis Environmental Research Laboratory, U. S. Environmental protection Agency, Corvallis, OR

    Katko, A
    Research aquatic biologist, supervisory research aquatic biologist, and aquatic biologist, Corvallis Environmental Research Laboratory, U. S. Environmental protection Agency, Corvallis, OR

    Rohm, CM
    Associate scientist, Northrop Services, Inc., Corvallis Environmental Research Laboratory, Corvallis, OR


    Paper ID: STP35255S

    Committee/Subcommittee: E47.01

    DOI: 10.1520/STP35255S


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