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| Titel |
Dynamics of dimethylsulphoniopropionate and dimethylsulphide under different CO2 concentrations during a mesocosm experiment |
| VerfasserIn |
M. Vogt, M. Steinke, S. Turner, A. Paulino, M. Meyerhöfer, U. Riebesell, C. LeQuéré, P. Liss |
| 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 ; 5, no. 2 ; Nr. 5, no. 2 (2008-03-18), S.407-419 |
| Datensatznummer |
250002374
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| Publikation (Nr.) |
 copernicus.org/bg-5-407-2008.pdf |
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| Zusammenfassung |
| The potential impact of seawater acidification on the
concentrations of dimethylsulfide (DMS) and dimethylsulfoniopropionate
(DMSP), and the activity of the enzyme DMSP-lyase was investigated during a pelagic ecosystem
CO2 enrichment experiment (PeECE III) in spring 2005. Natural
phytoplankton blooms were studied for 24 days under present, double and
triple partial pressures of CO2 (pCO2; pH=8.3, 8.0, 7.8) in
triplicate 25 m3 enclosures. The results indicate similar DMSP
concentrations and DMSP-lyase activity (DLA) patterns for all treatments. Hence,
DMSP and DLA do not seem to have been affected by the CO2 treatment. In
contrast, DMS concentrations showed small but statistically significant
differences in the temporal development of the low versus the high
CO2 treatments. The low pCO2 enclosures had higher DMS concentrations
during the first 10 days, after which the levels decreased earlier and more
rapidly than in the other treatments. Integrated over the whole study
period, DMS concentrations were not significantly different from those of
the double and triple pCO2 treatments. Pigment and flow-cytometric data
indicate that phytoplanktonic populations were generally similar between the
treatments, suggesting a certain resilience of the marine ecosystem under
study to the induced pH changes, which is reflected in DMSP and DLA.
However, there were significant differences in bacterial community structure
and the abundance of one group of viruses infecting nanoeukaryotic algae.
The amount of DMS accumulated per
total DMSP or chlorophyll-a differed significantly between the present and
future scenarios, suggesting that the pathways for DMS production or
bacterial DMS consumption were affected by seawater pH. A comparison with
previous work (PeECE II) suggests that DMS concentrations do not respond
consistently to pelagic ecosystem CO2 enrichment experiments. |
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