Linking the Effects of Land Use vs. Changing Climate on Water Quality in Ossipee and Squam Lakes, NH

With water quality as a key issue in water resource management, the need to understand the impacts of land use and climate on freshwater systems has never been greater. Lakes are particularly responsive to watershed changes, many of which are ephemeral, captured only by continuous monitoring. Lake sediments continuously record and archive lake conditions, potentially filling gaps in monitoring datasets. This study aims to identify transient, sub-annual changes in sedimentary archives, using integrated data from lake water chemistry, sediment traps and sediment cores in two northern lakes: Ossipee and Squam, NH. We compare our findings with documented records of local land use and climate change to determine how these manifest in our lake records. Our resulting time series include water column data for temperature, dissolved oxygen, major ions and phosphorus in depth profiles in eve1y season, and a sedimentary time series, extending to pre-Colonial times, which includes 210Pb activity, particle size, diatom community assemblages, and mineral chemistry. We use PCA and CA to identify sediment variables closely associated with water quality, climate, and land use indicators, which is then used to inform local community stakeholders on potential impacts of watershed changes