Whole lake responses to low level copper sulfate treatment

Abstract

The impact of three low level copper sulfate applications to Cazenovia Lake, New York, was assessed through a high frequency monitoring program. Monitored parameters included: (1) filtered and total copper; (2) phytoplankton identification and enumeration; (3) chlorophyll-a, (4) in situ14C assimilation; (5) bacteria numbers; (6) zooplankton identification and enumeration, (7) macrophyte nutrient status and (8) filtered reactive and total phosphorus. The low level application caused only small increases (maximum of 5 μg/l) of short duration (2-5 days) in filtered copper. The treatments failed to induce effective algicidal action in the target phytoplankton populations of the lake, but they did induce short term stress and alterations in the natural seasonal succession processes within these populations. No definitive responses in the zooplankton, submerged macrophytes or water column phosphorus levels were noted. Dramatic reductions in the water column bacteria occurred immediately following each treatment, indicating direct negative impact. Phytoplankton and bacteria populations recovered within 1 week and several days, respectively. © 1980.