||Responses of Plankton Communities in Experimental Ponds to Atrazine, the Most Heavily Used Pesticide in the United States.
DeNoyelles, F. ;
Kettle, W. D. ;
Sinn, D. E. ;
||Kansas Univ., Lawrence. Dept. of Systematics and Ecology.;Corvallis Environmental Research Lab., OR.
Water pollution ;
Chlorine organic compounds ;
Nitrogen heterocyclic compounds ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
Experimental ponds received single additions of the herbicide atrazine in concentrations of 20 and 500 mg/l, and were compared to control ponds for 136 d. Atrazine is an inhibitor of photosynthesis, and both concentrations depressed phytoplankton growth in the ponds within a few days. This was followed by successional changes leading to the establishment of species of phytoplankton more resistant to inhibition by atrazine. Laboratory studies verified this resistance and verified effects on other species at concentrations of atrazine as low as 1-5 mg/l. When and to what extent resistant species appeared in the phytoplankton communities differed with treatment. At the atrazine concentration of 500 mg/l, there was a delayed appearance but eventually a greater biomass and persistence of these species. The grazing zooplankton influenced these differences and were in turn affected by them. (Copyright (c) 1982 by the Ecological Society of America.)