Production of bioavailable and refractory dissolved organic matter by coastal heterotrophic microbial populations

Christian Lonborg, Xose Alvarez-Salgado, Keith Davidson, Axel Miller

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Production of dissolved organic matter (DOM) by heterotrophic microbial communities isolated from Loch Creran (Scotland) was studied in time course incubations in which cells were re-suspended in artificial seawater amended with variable proportions of glucose, ammonium and phosphate. The incubation experiments demonstrated that microheterotrophs released part of the substrate as new DOM, with a production efficiency of 11 +/- 1% for DOC, 18 +/- 2% for DON and 17 +/- 2% for DOP. Estimating the impact of this production in Loch Creran, showed that from 3 +/- 1% (DOC) to 72 +/- 16% (DOP) of DOM could originate from the heterotrophic microbial community. The produced DOM (PDOM) was both bioavailable (BDOM) and refractory (RDOM). Bioavailability as assessed by the difference between the maximum and the end DOM concentration, was generally higher than found in natural systems, with DOP (73 +/- 15%, average +/- SD) more bioavailable than DON (70 +/- 15%), and DON than DOC (34 +/- 13%). The stoichiometry of PDOM was linked to both nutrient uptake and BDOM ratios. Absorption and fluorescence of DOM increased significantly during the incubation time, indicating that microheterotrophs were also a source of coloured DOM (CDOM) and that they produce both bioavailable protein-like and refractory humic-like fluorophores. (C) 2009 Elsevier Ltd. All rights reserved.
Original languageEnglish
Pages (from-to)682-688
Number of pages7
JournalESTUAR COAST SHELF S
Volume82
Issue number4
DOIs
Publication statusPublished - 2009

Keywords

  • CARBON
  • RATIO
  • PHOSPHORUS
  • AMMONIUM REGENERATION
  • NITROGEN
  • MARINE BACTERIOPLANKTON
  • Marine & Freshwater Biology
  • BACTERIA
  • GROWTH
  • Oceanography
  • OCEAN
  • PHYTOPLANKTON

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