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| Titel |
Consistent increase in dimethyl sulfide (DMS) in response to high CO2 in five shipboard bioassays from contrasting NW European waters |
| VerfasserIn |
F. E. Hopkins, S. D. Archer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 18 ; Nr. 11, no. 18 (2014-09-16), S.4925-4940 |
| Datensatznummer |
250117594
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| Publikation (Nr.) |
 copernicus.org/bg-11-4925-2014.pdf |
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| Zusammenfassung |
| The ubiquitous marine trace gas dimethyl sulfide (DMS) comprises the
greatest natural source of sulfur to the atmosphere and is a key player in
atmospheric chemistry and climate. We explore the short-term response of
DMS production and cycling and that of its algal precursor dimethyl sulfoniopropionate (DMSP) to elevated carbon dioxide (CO2) and ocean acidification (OA)
in five 96 h shipboard bioassay experiments. Experiments were performed in
June and July 2011, using water collected from contrasting sites in NW European
waters (Outer Hebrides, Irish Sea, Bay of Biscay, North Sea). Concentrations
of DMS and DMSP, alongside rates of DMSP synthesis and DMS production and
consumption, were determined during all experiments for ambient CO2 and
three high-CO2 treatments (550, 750, 1000 μatm). In general, the
response to OA throughout this region showed little variation, despite
encompassing a range of biological and biogeochemical conditions. We
observed consistent and marked increases in DMS concentrations relative to
ambient controls (110% (28–223%) at 550 μatm, 153% (56–295%) at 750 μatm and 225% (79–413%) at 1000 μatm),
and decreases in DMSP concentrations (28% (18–40%)
at 550 μatm, 44% (18–64%) at 750 μatm and 52%
(24–72%) at 1000 μatm). Significant decreases in DMSP
synthesis rate constants (μDMSP, d−1) and DMSP production rates
(nmol d−1) were observed in two experiments (7–90% decrease),
whilst the response under high CO2 from the remaining experiments was
generally indistinguishable from ambient controls. Rates of bacterial DMS
gross consumption and production gave weak and inconsistent responses to
high CO2. The variables and rates we report increase our
understanding
of the processes behind the response to OA. This could provide the
opportunity to improve upon mesocosm-derived empirical modelling
relationships and to move towards a mechanistic approach for predicting future
DMS concentrations. |
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