INTEGRATING MONITORING WITH PALEOLIMNOLOGY TO DETERMINE CONNECTIONS BETWEEN CLIMATE AND WATER QUALITY IN CENTRAL NEW HAMPSHIRE

Changing climate is expected to significantly affect our water resources, impacting the hydrological processes and the quality of these resources. Due to the high heat capacity of water, and their large water volume, lakes are particularly susceptible to climate change. Despite this, the relationships between climate and water quality are poorly constrained. This study addresses that gap, by closely examining the response of water quality in two northern New England lakes to sub-seasonal climate forcing. We do this by monitoring physical and chemical water conditions at fixed moorings, combined with sediment trap and sediment core collections.

The resulting time series of water conditions include temperature, conductivity, dissolved oxygen, major ions and phosphorus in depth profiles at Ossipee and Squam lakes, NH in every season. These lake water conditions are compared with data from local weather and hydrological stations, to constrain lake responses to short-term meteorological conditions and events. PCA analyses help to identify water quality variables most closely associated with the climate data.

Sediment analyses and ²¹⁰Pb dating, to intervals prior to European settlement, expand the time series. The sediment analyses include particle size, mass magnetic susceptibility, organic carbon content, C/N ratios, diatom community assemblages and mineral chemistry. The project informs local community stakeholders, including lake management associations and conservation groups, on the potential implications of changing climate on their respective lakes to encourage proactive responses that address future water quality management needs.