- Shanley, James B.
US Geological Survey
Stream losses of DOC are often dismissed as an unimportant part of the global carbon budget. However, stream DOC flux in the temperate and boreal northern hemisphere has been increasing during the past two decades. Because changes in DOC concentrations and yields mirror changes in ecosystem processes that are sensitive to climate forcing, this study was designed to better quantify the stream DOC component of the C balance in watersheds in the northern forest region of the northeastern USA, using natural climatic variation to infer the magnitude and direction of future DOC shifts. This study built on two previous NSRC-funded studies, continuing measurements at three small watersheds: Arbutus Inlet, NY; Sleepers River W-9, VT; and Hubbard Brook WS-3, NH. We used in situ fluorometers to measure fluorescent dissolved organic matter (FDOM) as a proxy for DOC to: (1) accurately quantify DOC yields at high temporal resolution at three headwater streams, and (2) improve our understanding of the northern forest carbon cycle and its response to climatic perturbations.