SEASONAL WATER AND CHEMICAL FLUXES THROUGH A PEATLAND IN SOUTH CENTRAL MAINE

Wetlands occupy 2% of the Earth's surface, but account for 60% of the carbon removed from the atmosphere and 20% of the methane released into the atmosphere. In order to understand the role that wetlands play in global cycles, we must describe the physical and chemical processes that occur in wetlands in a quantitative fashion. This study is an effort to gain an understanding of seasonal groundwater and chemical fluxes through a peat bog in the Belgrade Lakes region in Maine.

The Serpentine Bog and Stream serve as water conduits between two small lakes in the Belgrade Lakes watershed. The bog is approximately 2.4km2 in area and consists of approximately 2.5 meters of peat overlying granitic bedrock. In order to determine the groundwater, surface water, and chemical fluxes from one lake to the other, we have installed 8 piezometer nests along 2 transects across the peatland. Each of the piezometer nests consist of one shallow piezometer (screened at 0.5m) and one deep piezometer (screened at 2m). Pressure transducers and dataloggers have been installed in the piezometers and stream to record water levels on an hourly basis. Water temperature, pH, ORP, and DO are measured in the field and water samples from each piezometer are analyzed for major cations [Ca+2, Mg+2, Na+, and K+], major anions [HCO3-, Cl-, and SO4-2], organics [TOC and DOC], and nutrients [NO3-, and PO4-2] on seasonal bases.

A climatological study of the Belgrade Lakes region conducted in tandem with this research has determined that there are 6 distinct seasons in central Maine based on daily mean temperature, precipitation, snowfall, snow depth, and calculated potential evapotranspiration. Our intent is to perform 6 samplings per year (one in each of the six hydrologic seasons) in order to determine the seasonal dynamics of groundwater flow through the bog and assess changes in chemical fluxes through the year. We will present results of the first two samplings along with our preliminary conclusions.