A PALEOLIMNOLOGIC PERSPECTIVE ON WATER QUALITY DEGRADATION IN A RURAL WATER BODY, LAKE WARNER, HADLEY, MASSACHUSETTS

Declining water quality and cultural eutrophication are common problems affecting lakes, ponds, and reservoirs throughout the world. Many instances of declining water quality have been linked to excess inputs of nutrients. Thus effective lake management relies on an understanding of the sources of nutrient enrichment to the subject body of water. Lake Warner is a small (surface area 0.28 km²; max depth 3.0 m) reservoir that was created by damming of the Mill River in Hadley, Massachusetts. The lake is currently experiencing water quality issues marked by high turbidity and excessive growth of aquatic macrophytes. In order to evaluate potential causes of declining water quality and place modern conditions in a long term context, this study is examining sediment cores collected from Lake Warner in October 2014. Age control for the cores is provided by Pb and Cs activity profiles. Sediment analyses are primarily focused on examining changes in the composition and accumulation rate of sediment in the lake based on measurements of sediment bulk density and loss on ignition along with indicators of sediment source (carbon and nitrogen isotopes) and primary productivity (diatom abundance and composition). Preliminary results indicate an abrupt change in sediment composition in the early to mid 20^th century followed by a continued trend towards an increased percentage of organic matter preserved in lake sediments. The change in sediment composition appears to coincide with a shift in the assemblage of diatom species preserved in the core.