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| Titel |
Impact of seawater pCO2 on calcification and Mg/Ca and Sr/Ca ratios in benthic foraminifera calcite: results from culturing experiments with Ammonia tepida |
| VerfasserIn |
D. Dissard, G. Nehrke, G. J. Reichart, J. Bijma |
| 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 ; 7, no. 1 ; Nr. 7, no. 1 (2010-01-07), S.81-93 |
| Datensatznummer |
250004366
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| Publikation (Nr.) |
 copernicus.org/bg-7-81-2010.pdf |
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| Zusammenfassung |
| Evidence of increasing concentrations of dissolved carbon dioxide,
especially in the surface ocean and its associated impacts on calcifying
organisms, is accumulating. Among these organisms, benthic and planktonic
foraminifera are responsible for a large amount of the globally precipitated
calcium carbonate. Hence, their response to an acidifying ocean may have
important consequences for future inorganic carbon cycling. To assess the
sensitivity of benthic foraminifera to changing carbon dioxide levels and
subsequent alteration in seawater carbonate chemistry, we cultured specimens
of the shallow water species Ammonia tepida at two concentrations of atmospheric CO2
(230 and 1900 ppmv) and two temperatures (10 °C and 15 °C). Shell
weights and elemental compositions were determined. Impact of high and low
pCO2 on elemental composition are compared with results of a previous
experiment were specimens were grown under ambient conditions (380 ppvm, no
shell weight measurements of specimen grown under ambient conditions are,
however, available). Results indicate that shell weights decrease with
decreasing [CO32−], although calcification was observed even in
the presence of calcium carbonate under-saturation, and also decrease with
increasing temperature. Thus both warming and ocean
acidification may act to decrease shell weights in the future. Changes in
[CO32−] or total dissolved inorganic carbon do not affect the Mg
distribution coefficient. On the contrary, Sr incorporation is enhanced
under increasing [CO32−]. Implications of these results for the
paleoceanographic application of foraminifera are discussed. |
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