The Impact of Stream Nutrient Loading on Metaphyton in Conesus Lake and the Use of Metaphyton Incubation Chambers for Measurement In Situ of Changes in Biomass

Abstract

Recently, the abundance of metaphyton (Zygnema and Spirogyra) in Conesus Lake has reached unprecedented levels. This dramatic increase has altered the ecological state of the littoral zone and may have cascading effects on the lake’s ecosystem. Studies conducted at SUNY Brockport have demonstrated that stream effluent entering the lake contains high concentrations of soluble reactive phosphorus and nitrate. The hypothesis that stream effluent was having a positive effect on the biomass of metaphyton was tested using continuous flow-through incubation chambers. Metaphyton responded in a significant positive manner when exposed to stream effluent. Analysis of nutrient concentrations determined throughout the incubation chamber experiments and results of an enrichment experiment, suggest that metaphyton in Conesus Lake is limited by phosphorous and not nitrate. Additionally, quantitative observations along transects were preformed to test the hypothesis that a close spatial relationship existed between the distribution of metaphyton and stream mouths. A close spatial relationship was not observed. Significantly higher percent cover of metaphyton was observed to the north or south of stream mouths (10 – 40 m away) when compared to percent cover directly in front of stream mouths. This pattern is attributed to disruptive forces of stream effluent during hydrometeorologic events.