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| Titel |
Calcification in the planktonic foraminifera Globigerina bulloides linked to phosphate concentrations in surface waters of the North Atlantic Ocean |
| VerfasserIn |
D. Aldridge, C. J. Beer, D. A. Purdie |
| 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 ; 9, no. 5 ; Nr. 9, no. 5 (2012-05-15), S.1725-1739 |
| Datensatznummer |
250007026
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| Publikation (Nr.) |
 copernicus.org/bg-9-1725-2012.pdf |
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| Zusammenfassung |
| Marine calcifiers, such as planktonic foraminifera, form a major component
of the global carbon cycle, acting as both a source and sink of CO2.
Understanding factors that affect calcification in these organisms is
therefore critical in predicting how the oceans will respond to increased
CO2 concentrations in the atmosphere. Here, size-normalised weights
(SNWs) of the planktonic foraminifera Globigerina bulloides, collected from the surface waters of
the North Atlantic Ocean, are compared with in situ carbonate ion
concentrations ([CO32–]), sea-surface temperature, optimum growth
conditions and nutrient concentrations. Changes in phosphate concentrations
([PO43–], range: 0.04–0.39 μM) explained the majority of G. bulloides SNW
variation, with reduced test masses at higher concentrations. Two factors
already known to influence calcification in foraminifers, [CO32–]
and temperature, were also positively correlated over the range of values
examined (148–181 μM kg−1 and 10.3–12.7 °C respectively). No
evidence was found for increased SNWs under apparent optimum growth
conditions, indicated by G. bulloides abundances. However, "growth potentials" (μ),
derived from modelled growth rates (d–1), were positively correlated
with SNWs, suggesting that this may be a better proxy for optimum growth
conditions. These findings point to the potential importance of
[PO43–] in determining calcification intensities in foraminifera,
a factor which has been overlooked by previous studies on these organisms.
The confirmation of this via carefully controlled culture studies is
recommended in the future. |
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