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| Titel |
Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, Porolithon onkodes in an experimental system |
| VerfasserIn |
M. C. Nash, S. Uthicke, A. P. Negri, N. E. Cantin |
| 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 ; 12, no. 17 ; Nr. 12, no. 17 (2015-09-14), S.5247-5260 |
| Datensatznummer |
250118087
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| Publikation (Nr.) |
 copernicus.org/bg-12-5247-2015.pdf |
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| Zusammenfassung |
| There are concerns that Mg-calcite crustose coralline algae (CCA), which are
key reef builders on coral reefs, will be most susceptible to increased rates
of dissolution under higher pCO2 and ocean acidification. Due to the
higher solubility of Mg-calcite, it has been hypothesised that magnesium
concentrations in CCA Mg-calcite will decrease as the ocean acidifies, and
that this decrease will make their skeletons more chemically stable. In
addition to Mg-calcite, CCA Porolithon onkodes, the predominant
encrusting species on tropical reefs, can have dolomite
(Ca0.5Mg0.5CO3) infilling cell spaces which increases their
stability. However, nothing is known about how bio-mineralised dolomite
formation responds to higher pCO2. Using P. onkodes grown for
3 and 6 months in tank experiments, we aimed to determine (1) if mol %
MgCO3 in new crust and new settlement was affected by increasing
CO2 levels (365, 444, 676 and 904 μatm), (2) whether
bio-mineralised dolomite formed within these time frames, and (3) if so,
whether this was effected by CO2. Our results show that there was no
significant effect of CO2 on mol % MgCO3 in any sample set,
indicating an absence of a plastic response under a wide range of
experimental conditions. Dolomite within the CCA cells formed within 3 months
and dolomite abundance did not vary significantly with CO2 treatment.
While evidence mounts that climate change will impact many sensitive coral
and CCA species, the results from this study indicate that reef-building
P. onkodes will continue to form stabilising dolomite infill under
near-future acidification conditions, thereby retaining its higher resistance
to dissolution. |
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