THE PHOSPHATE CONCENTRATION OF THE NORTH AND SOUTH BASINS OF LAKE CONESUS; ANTHROPOGENIC AND AGRICULTURAL LAND USE PRACTICES

The geohistorical record yields valuable data on past environmental and ecological changes that can be used as baselines for conservation and restoration. The study aims to look at anthropogenic effects specifically land use practices, and how these have influenced the sediment chemistry of Conesus Lake (Livingston County, NY). Conesus Lake is currently rated as a mesotrophic lake that has been undergoing continual remediation and monitoring since the introduction of invasive taxa and harmful cyano-algal blooms, caused by cultural eutrophication, in the mid-1990s. The watershed of Conesus Lake contains large amounts of land used for agricultural. Piston cores were collected from both the north and south basins of Conesus Lake at depths of 11m and 17m, respectively. Both cores were split, imaged, and analyzed for both magnetic susceptibility and XRF using a multi-sensor core logger. Sediments were subsampled and processed for diatoms and total organic carbon at regular six cm intervals. The phosphate concentration of both the north and south basin cores were further analyzed from 20 subsamples of differing depths from each core. Phosphate concentration was determined digesting sediment in a sulfuric acid solution and processed using a photometer. Preliminary results indicate a significant sedimentological change towards the recent where organic content dramatically decreases along with a coarsening of grain size. The elemental phosphorous concentrations remain stable in both basins but dramatically increase in concentration towards the present starting at 36cm in the north and 25cm below the lake floor in the south basin. North basin phosphate concentrations are minimal until 80cm from the top of the core, concentrations gradually becoming more elevated and increasing towards the present. The south basin shows higher phosphate concentrations than the north basin. Phosphate concentrations in the South basin gradually increase from 85cm to a peak at 25cm, followed by a decline towards the recent. Based on these results, phosphate delivery is more concentrated in the south due to higher sediment transport and more delivery systems. However, current remediation efforts seem to be ameliorating cultural eutrophication by reducing more recent phosphate concentrations captured in the lake.