Benthic decomposition of Zostera marina roots: a controlled laboratory experiment |
| |
Authors: | Anne Turi Amtoft Neubauer Kai Finster Andrew P Donnelly Gianmarco Giordani Bente Aa Lomstein |
| |
Institution: | a Department of Microbiology, Institute of Biological Sciences, University of Aarhus, Building 540, Ny Munkegade, DK-8000 Aarhus C, Denmark b Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK c Dipartimento di Scienze Ambientali, Università di Parma, Area Parco delle Scienze 33/A I-43100 Parma, Italy d Laboratoire d'Oceanographie Biologique, Station Marine d'Archachon, UMR 5805 CNRS and Université Bordeaux 1, 2, Rue de Prof. Jolyet, F 33120 Arcachon, France |
| |
Abstract: | The initial benthic decomposition of Zostera marina roots was studied in a controlled flow-through chamber experiment for 23 days. Sediment chambers without added roots served as controls. The inflowing and outflowing artificial seawater (ASW) was analyzed for O2, ΣCO2, urea-N, NH4+ and NO2−+NO3−. Sediment profiles of Eh, particulate organic carbon (POC) and nitrogen, dissolved organic nitrogen (DON), dissolved free amino acids (DFAA), urea-N, NH4+, DFAA and urea turnover rates, sulfate reduction and counts of total anaerobic heterotrophic bacteria and different functional groups were determined. Fluxes of O2, ΣCO2, urea-N and NH4+ were stimulated during root decomposition compared to the unamended control. There were indications of stimulated bacterial growth based on counts of total anaerobic heterotrophic bacteria, anaerobic phosphatase utilizers, ammonifyers and sulfate reducers. Independent estimates of nitrogen and carbon incorporation into bacterial biomass during root decomposition indicate that a major fraction of the nitrogen for microbial growth was mobilized from the indigenous particulate organic nitrogen (PON) pool, whereas the energy source for bacterial growth was mainly obtained from the added eelgrass roots. Most of the nitrogen mineralized during root decomposition was incorporated into the bacterial biomass resulting in a low efflux of urea-N and inorganic nitrogen from the sediment to the water column. |
| |
Keywords: | Benthic decomposition Seagrasses Nitrogen cycling Bacterial growth Coastal environment |
本文献已被 ScienceDirect 等数据库收录! |
|