title: Temporal succession in carbon incorporation from macromolecules by particle-attached bacteria in marine microcosms.
abstract: We investigated bacterial carbon assimilation from stable isotope-labelled macromolecular substrates (proteins; lipids; and two types of polysaccharides, starch and cellobiose) while attached to killed diatom detrital particles during laboratory microcosms incubated for 17 days. Using Chip-SIP (secondary ion mass spectrometry analysis of RNA microarrays), we identified generalist operational taxonomic units (OTUs) from the Gammaproteobacteria, belonging to the genera Colwellia, Glaciecola, Pseudoalteromonas and Rheinheimera, and from the Bacteroidetes, genera Owenweeksia and Maribacter, that incorporated the four tested substrates throughout the incubation period. Many of these OTUs exhibited the highest isotope incorporation relative to the others, indicating that they were likely the most active. Additional OTUs from the Gammaproteobacteria, Bacteroidetes and Alphaproteobacteria exhibited generally (but not always) lower activity and did not incorporate all tested substrates at all times, showing species succession in organic carbon incorporation. We also found evidence to suggest that both generalist and specialist OTUs changed their relative substrate incorporation over time, presumably in response to changing substrate availability as the particles aged. This pattern was demonstrated by temporal succession from relatively higher starch incorporation early in the incubations, eventually switching to higher cellobiose incorporation after 2 weeks.
authors.affiliation: Physical and Life Science Directorate, Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, CA, 94550, USA.
authors.forename: Xavier
authors.initials: X
authors.lastname: Mayali
authors.affiliation: Physical and Life Science Directorate, Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, CA, 94550, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Stewart
authors.affiliation: Physical and Life Science Directorate, Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, CA, 94550, USA.
authors.forename: Shalini
authors.initials: S
authors.lastname: Mabery
authors.affiliation: Physical and Life Science Directorate, Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, CA, 94550, USA.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Weber
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000378:metabolism*; D001422:Bacterial Adhesion; D002244:Carbon / Q000378:metabolism*; D019015:Geologic Sediments / Q000382:microbiology*; D007553:Isotope Labeling; D046911:Macromolecular Substances / Q000378:metabolism*; D046228:Microarray Analysis; D012329:RNA, Bacterial / Q000032:analysis; D018629:Spectrometry, Mass, Secondary Ion
chemical_list: D046911:Macromolecular Substances; D012329:RNA, Bacterial; D002244:Carbon