HR: 14:40h
AN: C53A-04 [Abstracts]
TI: Linking River-to-Ocean Through Temporal and Spatial Variation in Runoff Tracers in the Arctic
Ocean
AU: * Cooper, L W
EM: lcooper1@utk.edu
AF: University of Tennessee, Marine Ecology and Biogeochemistry Group, Department of Ecology and
Evolutionary Biology, 10515 Research Dr, Suite 100, Knoxville, TN 37932
United States
AU: Benner, R
EM: benner@biol.sc.edu
AF: University of South Carolina, Biological Sciences and Marine Science Program, Columbia, SC 29208
United States
AU: Grebmeier, J M
EM: jgrebmei@utk.edu
AF: University of Tennessee, Marine Ecology and Biogeochemistry Group, Department of Ecology and
Evolutionary Biology, 10515 Research Dr, Suite 100, Knoxville, TN 37932
United States
AU: McClelland, J W
EM: jmcclelland@mbl.edu
AF: Marine Biological Laboratory, The Ecosystems Center, 7 MBL St, Woods Hole, MA 02543
United States
AU: Peterson, B J
EM: peterson@mbl.edu
AF: Marine Biological Laboratory, The Ecosystems Center, 7 MBL St, Woods Hole, MA 02543
United States
AU: Holmes, R M
EM: rholmes@mbl.edu
AF: Marine Biological Laboratory, The Ecosystems Center, 7 MBL St, Woods Hole, MA 02543
United States
AU: Codispoti, L A
EM: codispot@hpl.umces.edu
AF: University of Maryland Center for Environmental Studies, PO Box 775, Cambridge, MD 21613
United States
AU: Hansell, D A
EM: dhansell@rsmas.miami.edu
AF: University of Miami, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway,
Miami, FL 33149
United States
AB:
The mixing of runoff into surface water of the Arctic Ocean has been incompletely resolved because of limited seasonal
sampling. Pan-Arctic River Transport of Nutrients, Organic Matter and Suspended Sediments (PARTNERS) and Shelf Basin
Interactions (SBI) are two on-going research programs that are now helping to document more extensive seasonal variation in
runoff tracers such as oxygen-18/oxygen-16 ratios, lignin, dissolved organic carbon (DOC), and excitation fluorometry at
major river mouths, and over the shelf, slope and basin of the Arctic Ocean. Using data that indicate multi-annual
persistence of the runoff signal in offshore surface waters entrained in the Beaufort Gyre, we show that the oxygen isotope
end-member for runoff is modulated seasonally and is dependent upon both river source and seasonal path of input. A Haardt
fluorometer used in 2002 on the SBI cruises on the Chukchi and Beaufort Seas was not well correlated with DOC as has been
observed in the Eurasian Arctic. However, data from a denitrification indicator, N**, also serves as a functional tracer for
Bering Sea-origin waters that have been in contact with continental shelf sediments. This nutrient-based indicator is well
correlated with the Haardt fluorometer signal in the Chukchi Sea in the absence of freshwater contributions from melted sea
ice. This suggests that release of organic materials from productive continental shelf sediments may also influence the
Haardt fluorometer signal independent of runoff DOC. Experimental shipboard incubations of shelf and slope sediments
corroborate significant releases of DOC from benthic sediments. Seasonal variation in the oxygen isotope composition of
runoff, among various Arctic river sources and the river component within Bering Strait as well as the introduction of
freshwater contributed from melted sea ice will also be discussed.
UR: http://arctic.bio.utk.edu
DE: 9315 Arctic region
DE: 4536 Hydrography
DE: 1655 Water cycles (1836)
DE: 1836 Hydrologic budget (1655)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting