SS2.04 Microbial Stoichiometry and Impacts on Biogeochemistry: From Genes to the Biosphere
Date: Friday, June 14, 2002
Time: 8:45:00 AM
Location: Carson C
 
HopkinsonCS, Marine Biological Laboratory, Woods Hole, USA, chopkins@mbl.edu
Vallino, J, J, Marine Biological Laboratory, Woods Hole, USA, jvallino@mbl.edu
 
Decomposition of dissolved organic matter from the continental margin
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Decomposition of DOC, DON, and DOP was measured for surface and bottom waters of shelf, deep, slope water along the Middle Atlantic Bight. On average the C:N:P ratio of shelf DOM (431:36:1) was substantially higher than the Redfield ratio, but not nearly as high for that of deep, slope water (2700:215:1). Decomposition time course data were fit to a 3-pool (very labile, labile and recalcitrant pools) multi-G model. There were major differences in the relative amount of very labile, labile and recalcitrant fractions of shelf water DOC, DON and DOP as a result of preferential remineralization of P over N and N over C. Averaged over stations, the decomposable portion of the bulk DOC, DON and DOP pools increased from 30% to 40% to 81% for C, N and P. There was a wide range in decay coefficients for the very labile and labile DOM pools: average decay coefficient for the very labile pool was 0.219 per day and 0.018 per day for the labile pool.