- Tracing carbon flow from microphytobenthos to major bacterial groups in an intertidal marine sediment by using an in situ 13C pulse-chase method
- Limnology and Oceanography
- Volume | Issue number
- 59 | 4
- Pages (from-to)
- Document type
- Faculty of Science (FNWI)
- Institute for Biodiversity and Ecosystem Dynamics (IBED)
Carbon flow from benthic diatoms to heterotrophic bacterial was traced in an intertidal sediment for 5 consecutive days. 13C-labeled bicarbonate was sprayed onto the sediment surface during low tide and 13C-label incorporation in major carbon pools, intermediate metabolites, and biomarkers were monitored. Phospholipid-derived fatty acid (PLFA) and ribosomal ribonucleic acid (rRNA) were used to identify the responsible members of the microbial community at class and family phylogenetic resolution. Diatoms were the predominant primary producers, and Gammaproteobacteria, Bacteroidetes, and Deltaproteobacteria (21%, 8%, and 7% of 16S rRNA-derived clone library) were major heterotrophic bacterial groups. Both 13C-PLFA and 13C-rRNA data suggest a fast transfer of label from diatoms (60 nmol 13C g−1 dry weight [dry wt]) to bacteria (7 nmol 13C g−1 dry wt) during the first 24 h, which was probably due to the exudation of low-molecular-weight organic compounds by diatoms that could be directly utilized by bacteria. After this initial fast transfer, labeling of bacteria proceeded at a slower rate to 13 nmol 13C g−1 dry wt on the third day of the experiment, which coincided with the degradation of carbohydrates in water-extractable extracellular polymeric substances (EPS) initially produced by the diatoms. Water-extractable EPS (primarily as glucose) was a major intermediate and its turnover explained 75% of the total carbohydrate processing in the sediment. Labeling in bacteria tracked labeling in the diatoms, suggesting a closely coupled system. The heterotrophic bacterial groups benefited equally from the organic matter released by the diatoms, suggesting limited specialization in this microbial food web.
- go to publisher's site
If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library, or send a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible.