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| Titel |
Influence of changing carbonate chemistry on morphology and weight of coccoliths formed by Emiliania huxleyi |
| VerfasserIn |
L. T. Bach, C. Bauke, K. J. S. Meier, U. Riebesell, K. G. Schulz |
| 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. 8 ; Nr. 9, no. 8 (2012-08-30), S.3449-3463 |
| Datensatznummer |
250007257
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| Publikation (Nr.) |
 copernicus.org/bg-9-3449-2012.pdf |
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| Zusammenfassung |
| The coccolithophore Emiliania huxleyi is a marine phytoplankton species capable of forming
small calcium carbonate scales (coccoliths) which cover the organic part of
the cell. Calcification rates of E. huxleyi are known to be sensitive to changes in
seawater carbonate chemistry. It has, however, not yet been clearly
determined how these changes are reflected in size and weight of individual
coccoliths and which specific parameter(s) of the carbonate system drive
morphological modifications. Here, we compare data on coccolith size,
weight, and malformation from a set of five experiments with a large
diversity of carbonate chemistry conditions. This diversity allows
distinguishing the influence of individual carbonate chemistry parameters
such as carbon dioxide (CO2), bicarbonate (HCO3−), carbonate
ion (CO32−), and protons (H+) on the measured parameters.
Measurements of fine-scale morphological structures reveal an increase of
coccolith malformation with decreasing pH suggesting that H+ is the
major factor causing malformations. Coccolith distal shield area varies from
about 5 to 11 μm2. Changes in size seem to be mainly induced by
varying [HCO3−] and [H+] although influence of
[CO32−] cannot be entirely ruled out. Changes in coccolith weight
were proportional to changes in size. Increasing CaCO3 production rates
are reflected in an increase in coccolith weight and an increase of the
number of coccoliths formed per unit time. The combined investigation of
morphological features and coccolith production rates presented in this
study may help to interpret data derived from sediment cores, where
coccolith morphology is used to reconstruct calcification rates in the water
column. |
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