Document Detail

Counterintuitive carbon-to-nutrient coupling in an Arctic pelagic ecosystem.
MedLine Citation:
PMID:  18716617     Owner:  NLM     Status:  MEDLINE    
Predicting the ocean's role in the global carbon cycle requires an understanding of the stoichiometric coupling between carbon and growth-limiting elements in biogeochemical processes. A recent addition to such knowledge is that the carbon/nitrogen ratio of inorganic consumption and release of dissolved organic matter may increase in a high-CO(2) world. This will, however, yield a negative feedback on atmospheric CO(2) only if the extra organic material escapes mineralization within the photic zone. Here we show, in the context of an Arctic pelagic ecosystem, how the fate and effects of added degradable organic carbon depend critically on the state of the microbial food web. When bacterial growth rate was limited by mineral nutrients, extra organic carbon accumulated in the system. When bacteria were limited by organic carbon, however, addition of labile dissolved organic carbon reduced phytoplankton biomass and activity and also the rate at which total organic carbon accumulated, explained as the result of stimulated bacterial competition for mineral nutrients. This counterintuitive 'more organic carbon gives less organic carbon' effect was particularly pronounced in diatom-dominated systems where the carbon/mineral nutrient ratio in phytoplankton production was high. Our results highlight how descriptions of present and future states of the oceanic carbon cycle require detailed understanding of the stoichiometric coupling between carbon and growth-limiting mineral nutrients in both autotrophic and heterotrophic processes.
T F Thingstad; R G J Bellerby; G Bratbak; K Y Børsheim; J K Egge; M Heldal; A Larsen; C Neill; J Nejstgaard; S Norland; R-A Sandaa; E F Skjoldal; T Tanaka; R Thyrhaug; B Töpper
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-08-20
Journal Detail:
Title:  Nature     Volume:  455     ISSN:  1476-4687     ISO Abbreviation:  Nature     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-09-18     Completed Date:  2008-10-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0410462     Medline TA:  Nature     Country:  England    
Other Details:
Languages:  eng     Pagination:  387-90     Citation Subset:  IM    
Department of Biology, University of Bergen, Jahnebakken 5PO Box 7800, 5020 Bergen, Norway.
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MeSH Terms
Arctic Regions
Atmosphere / chemistry
Autotrophic Processes / drug effects,  radiation effects
Bacteria / drug effects,  growth & development,  metabolism,  radiation effects
Carbon / metabolism*
Carbon Dioxide / metabolism
Diatoms / metabolism,  radiation effects
Food Chain
Glucose / metabolism,  pharmacology
Heterotrophic Processes / drug effects,  radiation effects
Phytoplankton / drug effects,  growth & development,  metabolism,  radiation effects
Reg. No./Substance:
124-38-9/Carbon Dioxide; 50-99-7/Glucose; 7440-44-0/Carbon

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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