Chasar, L. S.. Department of Oceanography, Florida State University, stalder@ocean.fsu.edu
Chanton, J. S.. Department of Oceanography, FSU, jchanton@mailer.fsu.edu
Glaser, P. Department of Geology and Geophysics, University of Minnesota, glase001@tc.umn.edu
Siegel, D. I.. Earth Sciences, Heroy Geology Laboratory, Syracuse University, disiegel@mailbox.syr.edu
Rivers, J. S.. Heroy Geology Laboratory, Syracuse University,
Wolgast, D. Scripps, Mt. Soledad Radiocarbon Lab, wolgast@ucsd.edu

 
MICROBIAL RESPIRATION WITHIN 3000-5000 YEAR-OLD PEAT IS DRIVEN BY RECENTLY FIXED SURFICIAL DOC ADVECTED AS DEEP AS THREE METERS INTO THE PEAT COLUMN
 
Radiocarbon values for DOC, DIC , CH4 and solid phase material were obtained at 0.2m intervals for 0.2-2.8 m in a bog and fen in Minnesota's Upper Red Lake area of the Glacial Lake Agasiz peatland. To our knowledge, this is the most complete radiocarbon data set for any wetland to date. To support these data, complete porewater profiles were obtained for the following parameters: [DOC], [CH4] and [DIC]; del 13C values for CH4 and DIC; and del D/H for CH4. These data indicate that DOC of recent photosynthetic origin is being advected downward into the peat column. Radiocarbon content of DOC is similar in the bog and the fen, and substantially enriched relative to the solid phase peat. Radiocarbon values for DIC and CH4 track the DOC closely in the fen but are intermediate between DOC and the peat in the bog. In the bog, porewater CH4 and DIC were derived from a mixture of both modern and old organic substrates. In the fen, CH4 and DIC were more radiocarbon enriched. With groundwater discharge thought to be more important in the fen these results are surprising, as the fen should have radiocarbon-depleted DIC .
 
Day: Tuesday, Feb. 2
Time: 11:45 - 12:00pm
Location: Eldorado Hotel
 
Code: SS34TU1145E