Patterns of extracellular enzyme activities among pelagic marine microbial communities: implications for cycling of dissolved organic carbon

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 38:135-145 (2005) - doi:10.3354/ame038135 Patterns of extracellular enzyme activities among pelagic marine microbial communities: implications for cycling of dissolved organic carbon C. Arnosti1,*, S. Durkin2, W. H. Jeffrey2 1Department of Marine Sciences, University of North Carolina, CB#3300, 12-7 Venable Hall, Chapel Hill,North Carolina 27599, USA 2Center for Environmental Diagnostics and Bioremediation, University of West Florida, 11000 University Parkway,Pensacola, Florida 32514, USA *Email: arnosti@email.unc.edu ABSTRACT: The potential for pelagic microbial communities to hydrolyze high molecular weight substrates and therefore to initiate remineralization of high-molecular-weight dissolved organic carbon (DOC) was assessed at 8 different stations spanning a range of locations. Six structurally diverse polysaccharides were used to investigate activities and structural specificities of a related class of microbial extracellular enzymes, the polysaccharide hydrolases. Three high-latitude (57 to 79° N) stations showed similar rates and patterns of enzyme activity, with only 3 of 6 polysaccharides hydrolyzed. Hydrolysis at the other stations (39° S to 29° N) showed a variety of patterns, in which 2 to 5 of the polysaccharides were hydrolyzed. One of the polysaccharides, fucoidan, was not hydrolyzed at any station, while only laminarin was hydrolyzed at every station. A limited ability of microbial communities in some locations to hydrolyze high-molecular-weight substrates could help explain the persistence of a fraction of DOC in the ocean. Potential hydrolysis rates showed no correlation with factors such as environmental temperature or total cell numbers. Denaturing gradient gel electrophoresis analysis of community 16S rDNA indicated that the microbial communities at these locations were diverse, consistent with the diversity in patterns of enzyme activities. KEY WORDS: Extracellular enzyme · DOC · Carbon cycling · Polysaccharide Full article in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 38, No. 2. Online publication date: February 09, 2005 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2005 Inter-Research.