Differential metabolism of dimethylsulfoniopropionate and acrylate in saline and brackish intertidal sediments

摘要: In anoxic Spartina altemiflora—dominated sediments along a naturally occuring salinity gradient (the Cooper River estuary, South Carolina, U.S.A.), dimethylsulfoniopropionate (DMSP) was metabolized to dimethyl sulfide (DMS) and acrylate by sediment microbes. The rate of DMSP degradation mineralization microbes similar at all sites this 25-km transect. However, amended with (or DMSP) showed significantly higher rates N2 fixation (measured as acetylene reduction activity) (ARA) in the saline downstream than brackish sediments. These results are consistent fact that stimulated both denitrification CO2 production mouth river more tenfold over Enrichment experiments indicate capable using or were not present upstream despite microbial biomass, percent organic matter, glucose-stimulated ARA highest upstream. It appears utilizing, fixing, denitrifying populations insignificant lower estuary. may reflect availability DMSP, which averaged 10.3 nmol g wet wt−1 levels less our detection limit (1 μm)