Climate and hydrologic changes are expected to alter the timing and magnitude of land-to-ocean carbon transport in the Gulf of Maine
Thomas
G
Huntington, U.S. Geological Survey, thunting@usgs.gov
(Presenting)
George
R
Aiken, U.S. Geological Survey, graiken@usgs.gov
Documented 20th century trends in climatic and hydrologic variables in the northeastern USA could have affected land-to-ocean carbon transport. These trends are expected to continue and new trends are expected to emerge in the 21st century as the climate system adapts to ongoing changes in atmospheric chemistry. Observed trends include earlier snowmelt dominated high spring flow, higher rainfall intensities and associated higher peak flows, and longer dry periods between rainfalls. Trends expected to emerge include increases in high flows, decreases in low flows and lengthening of the low-flow season in summer, increasing rainfall overall (particularly during winter), and an increasing proportion of annual runoff occurring during winter. These changes in hydrologic regime will result in changes in the timing and magnitude of the export of dissolved organic carbon (DOC) from terrestrial landscapes to the coastal ocean. Water quality and streamflow data collected from 2004 to 2007 provide a basis for modeling daily export of DOC in three major rivers draining to the Gulf of Maine (GOM). Recent regional climate and hydrologic modeling allows us to investigate the potential effects of 21st century projected climate changes on the delivery of DOC to the GOM. Earlier high spring flows, increasing winter flows, and a longer summer low flow period are expected to increase DOC export during winter and early spring months and reduce DOC export from mid-to-late spring through fall months. Proportionately more DOC is expected to be transported during large storms compared to smaller storms or low flow conditions.
NASA Carbon Cycle & Ecosystems Active Awards Represented by this Poster: