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,
Vallino, J, J, Marine Biological Laboratory, Woods Hole, USA,
Decomposition of dissolved organic matter from the continental margin
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.