HISTORICAL TRENDS PRESERVED IN THE SEDIMENT RECORD: KEZAR LAKE

The annual deposition of sediments in lake systems creates a snapshot of environmental conditions during that year. Sediment cores taken from the lake bottom provide valuable insight into how the system has changed over long periods of time. Depending on the rate of deposition, a core can encompass anywhere from a few decades to a couple centuries. This allows us to glance further into the past than relatively short-term records of lake monitoring would allow. Analyzing trends preserved in the sediment record can allow us to observe and predict the impacts of changing environmental conditions over time on lake geology and ecology.

This study focuses on Kezar Lake, which is located in Lovell, Maine. A total of five sediment cores were taken from the lake bottom, split between two sample sites. Each core was divided into samples at one-centimeter intervals, yielding around 50 samples per core (~250 samples in total). We recorded a plethora of physical measurements for each sample, including wet/dry weights, density, particle size, and percent H2O composition. We also tested samples for both organic content and mass susceptibility. Comparing datasets from each initial sampling location gives us an idea of how the lake has changed over time, as well as what kinds of events may have initiated those changes.