AN INVESTIGATION OF THE HYDROGEOCHEMICAL DYNAMICS OF A FORESTED PEATLAND IN CENTRAL MAINE

Investigation of the physical and chemical processes that operate in small watersheds is one of the keys to understanding global hydrological and biogeochemical cycles. The Belgrade Lakes Watershed in Central Maine provides an ideal location for such an investigation because it is a well-defined system that is small enough to instrument and monitor at high resolution. This watershed also allows for the evaluation of seasonal changes in storage because a relatively large portion of the watershed is wetland and because there is significant snow-pack during the winter months.

Great Bog is an excellent example of a freshwater northern peatland located in the Belgrade Lakes Watershed. It is flanked by local bedrock to the east, the Horse Point esker to the west, and Great Pond to the north. Previous work has yielded a 14C date of about 8500 y BP at the base of the peat and has indicated that Great Bog was an open water embayment until about 6500 y BP.

We are currently monitoring the southern portion of Great Bog in an attempt to quantify the seasonal dynamics of the peatland hydrogeochemistry. We have pulled 10 vibracores, correlated the stratigraphy along two transects, and determined the water content of the sediments. We have also installed a piezometer nest (with wells at ~0.9m, 1.7m, and 3.2m) at each core location and we are measuring water levels and major ion chemistry of these 30 wells on a monthly basis. We will present the results of our investigation and discuss how our data provides insight into the processes that operate in small watersheds.