Resource quantity affects benthic microbial community structure and growth efficiency in a temperate intertidal mudflat

Daniel J Mayor, Barry Thornton, Alain F Zuur

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)
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Abstract

Estuaries cover <1% of marine habitats, but the carbon dioxide (CO 2) effluxes from these net heterotrophic systems contribute significantly to the global carbon cycle. Anthropogenic eutrophication of estuarine waterways increases the supply of labile substrates to the underlying sediments. How such changes affect the form and functioning of the resident microbial communities remains unclear. We employed a carbon-13 pulse-chase experiment to investigate how a temperate estuarine benthic microbial community at 6.5°C responded to additions of marine diatom-derived organic carbon equivalent to 4.16, 41.60 and 416.00 mmol C m -2. The quantities of carbon mineralized and incorporated into bacterial biomass both increased significantly, albeit differentially, with resource supply. This resulted in bacterial growth efficiency increasing from 0.40±0.02 to 0.55±0.04 as substrates became more available. The proportions of diatom-derived carbon incorporated into individual microbial membrane fatty acids also varied with resource supply. Future increases in labile organic substrate supply have the potential to increase both the proportion of organic carbon being retained within the benthic compartment of estuaries and also the absolute quantity of CO 2 outgassing from these environments.
Original languageEnglish
Article numbere38582
Number of pages6
JournalPloS ONE
Volume7
Issue number6
DOIs
Publication statusPublished - 18 Jun 2012

Keywords

  • bacterial growth efficiency
  • biogeochemistry
  • carbon mineralization
  • resource quantity
  • stable isotope
  • estuary
  • carbon dioxide
  • PLFA
  • microbial community metabolism
  • CO2
  • eutrophication
  • pulse-chase
  • carbon-13

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