Identification of Ombrotrophic Bogs in the Catskill Mountains, NY by Geochemical and Isotopic Methods

Ombrotrophic peatlands are those that are purely fed by precipitation and are unconnected to groundwaters. Identification of ombrotophic peatlands is of interest because of their utility as a depositional archive, their unique botanical characteristics, and their sensitivity to climate change. Seven high elevation peatlands in the Catskill Mountains of New York state are investigated in this paper; six of these are identified as ombrotrophic bogs and one is determined to be a minerotrophic (groundwater-fed) poor fen. In order to identify these peatlands as ombrotrophic, concentrations of major ions in surface pools are examined; the proportion of calcium and magnesium in surface pools is particularly indicative of ombrotrophy. Average Ca/Mg (mg L−1) ratios in bogs, precipitation, and springs are 4.3, 5.0, and 6.7, respectively. Stable isotopes of water (deuterium and 18O) are examined as well and may provide a novel method of determining the water source to peatlands; peatland isotopic data plot along what appears to be a local evaporation line.