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Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, Porolithon onkodes in an experimental system.
- Source :
- Biogeosciences Discussions; 2015, Vol. 12 Issue 2, p1373-1404, 32p
- Publication Year :
- 2015
-
Abstract
- 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 pCO<subscript>2</subscript> and ocean acidification. Due to the higher solubility of Mg-calcite, it has been hypothesized 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 (Ca<subscript>0.5</subscript>Mg<subscript>0.5</subscript>CO<subscript>3</subscript>) 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%MgCO<subscript>3</subscript> in new crust and new settlement affected by increasing pCO<subscript>2</subscript> levels (365, 444, 676 and 904 ppm), (2) whether bio-mineralised dolomite formed within these time frames, and (3) if so, whether this was effected by pCO<subscript>2</subscript>. Our results show there was no significant effect of pCO<subscript>2</subscript> on mol%MgCO<subscript>3</subscript> 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 pCO<subscript>2</subscript> 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 re- taining its higher resistance to dissolution. [ABSTRACT FROM AUTHOR]
- Subjects :
- OCEAN acidification
DOLOMITE
CORALLINE algae
OGCODES
CORALS
DISSOLUTION (Chemistry)
Subjects
Details
- Language :
- English
- ISSN :
- 18106277
- Volume :
- 12
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Biogeosciences Discussions
- Publication Type :
- Academic Journal
- Accession number :
- 100786446
- Full Text :
- https://doi.org/10.5194/bgd-12-1373-2015