HR: 0800h
AN: PP31B-0424    [Abstracts]
TI: Tracing Environmental Variation Over The Past 130 Years In The Barents Sea: Mineral Ratio (Mg/Ca, Sr/Ca, Ba/Ca, And Mn/Ca) Evidence In Shells Of The Circumpolar Greenland Cockle, Serripes groenlandicus
AU: * Henkes, G A
EM: GHenkes@bates.edu
AF: Bates College Department of Biology, Carnegie Science Building, Lewiston, ME 04240, United States
AU: Ambrose, W G
EM: wambrose@bates.edu
AF: Bates College Department of Biology, Carnegie Science Building, Lewiston, ME 04240, United States
AU: Johnson, B J
EM: bjohnso3@bates.edu
AF: Bates College Department of Geology, Carnegie Science Building, Lewiston, ME 04240, United States
AU: Carroll, M L
EM: michael.carroll@akvaplan.niva.no
AF: Akvaplan-Niva AS, Polar Environmental Center, Tromso, NC N-9296, Norway
AU: McMahon, K W
EM: kmcmahon@whoi.edu
AF: MIT/WHOI Joint Program, Clark Laboratory 223, MS 31, Woods Hole, MA 02543, United States
AU: Denisenko, S G
AF: Laboratory of Marine Research, Zoological Institute RAS, St. Petersburg, NC 00000, Russian Federation
AU: Thorrold, S R
EM: sthorrold@whoi.edu
AF: MIT/WHOI Joint Program, Clark Laboratory 223, MS 31, Woods Hole, MA 02543, United States
AB: In order to quantify the impacts of human induced climate change on Arctic marine ecosystems it is crucial to establish high-resolution proxies to record regional environmental variability. The Barents Sea region is highly influenced by the annual recession and precession of Arctic sea ice and, as an ecosystem is extremely sensitive to seasonal to decadal climatic changes. Long-lived, sessile, marine bivalves have the potential to provide detailed oceanographic and biological proxy information from the Barents Sea in locations where historic, long- term data logging does not exist. Here, we present preliminary mineral ratio evidence (Mg, Sr, Ba, Mn) for Barents Sea environmental variation from shells of the circumpolar Greenland cockle, Serripes groenlandicus, over the past 130 years from 4 different locations in Norwegian and Russian waters. For all mineral ratios there are clear seasonal trends corresponding with dark winter growth checks on the external surface of each individual. The seasonal patterns of Mg and Sr show progressive change. On average for 9 individuals, Mg/Ca was 10.6 percent greater and Sr/Ca was 5.5 percent lower on the winter checks compared to other values, while Ba/Ca and Mn/Ca ratios show peaks during the middle of the summer growth period. Mineral patterns from the Pechora Sea region are particularly pronounced, which may be related to the influence freshwater from summer river discharge. While the mineral data are initially compelling enough to demonstrate clear seasonal periodicity and inter-annual variation, we believe that a multi-proxy approach to interpreting the information obtained from these bivalves is critical. Therefore, parallel to this study, we are examining external, incremental growth and organic carbon isotopes of shell material from the same collection of bivalves.
DE: 4803 Analytical chemistry
DE: 4804 Benthic processes, benthos (0408)
DE: 4825 Geochemistry
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4924 Geochemical tracers
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting