title: Combined Carbohydrates Support Rich Communities of Particle-Associated Marine Bacterioplankton.
abstract: Carbohydrates represent an important fraction of labile and semi-labile marine organic matter that is mainly comprised of exopolymeric substances derived from phytoplankton exudation and decay. This study investigates the composition of total combined carbohydrates (tCCHO; >1 kDa) and the community development of free-living (0.2-3 μm) and particle-associated (PA) (3-10 μm) bacterioplankton during a spring phytoplankton bloom in the southern North Sea. Furthermore, rates were determined for the extracellular enzymatic hydrolysis that catalyzes the initial step in bacterial organic matter remineralization. Concentrations of tCCHO greatly increased during bloom development, while the composition showed only minor changes over time. The combined concentration of glucose, galactose, fucose, rhamnose, galactosamine, glucosamine, and glucuronic acid in tCCHO was a significant factor shaping the community composition of the PA bacteria. The richness of PA bacteria greatly increased in the post-bloom phase. At the same time, the increase in extracellular β-glucosidase activity was sufficient to explain the observed decrease in tCCHO, indicating the efficient utilization of carbohydrates by the bacterioplankton community during the post-bloom phase. Our results suggest that carbohydrate concentration and composition are important factors in the multifactorial environmental control of bacterioplankton succession and the enzymatic hydrolysis of organic matter during phytoplankton blooms.
authors.affiliation: Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine ResearchBremerhaven, Germany; Biologische Anstalt Helgoland, Alfred-Wegener-Institute Helmholtz-Center for Polar and Marine ResearchHelgoland, Germany; Biological Oceanography, Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research KielKiel, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Sperling
authors.affiliation: Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine ResearchBremerhaven, Germany; Biological Oceanography, Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research KielKiel, Germany.
authors.forename: Judith
authors.initials: J
authors.lastname: Piontek
authors.affiliation: Biological Oceanography, Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research Kiel Kiel, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Engel
authors.affiliation: Biologische Anstalt Helgoland, Alfred-Wegener-Institute Helmholtz-Center for Polar and Marine Research Helgoland, Germany.
authors.forename: Karen H
authors.initials: KH
authors.lastname: Wiltshire
authors.affiliation: Research Group for Marine Geochemistry (ICBM-MPI Bridging Group), Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg Oldenburg, Germany.
authors.forename: Jutta
authors.initials: J
authors.lastname: Niggemann
authors.affiliation: Biologische Anstalt Helgoland, Alfred-Wegener-Institute Helmholtz-Center for Polar and Marine Research Helgoland, Germany.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Gerdts
authors.affiliation: Biologische Anstalt Helgoland, Alfred-Wegener-Institute Helmholtz-Center for Polar and Marine Research Helgoland, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Wichels
keywords: Helgoland Roads; North Sea; bacterioplankton community; extracellular enzymes; organic matter; phytoplankton bloom; remineralization; spring bloom