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Morphological plasticity of the coral skeleton under CO2-driven seawater acidification.

Tambutté E, Venn AA, Holcomb M, Segonds N, Techer N, Zoccola D, Allemand D, Tambutté S - Nat Commun (2015)

Bottom Line: Ocean acidification causes corals to calcify at reduced rates, but current understanding of the underlying processes is limited.Instead, changes occur by enlargement of corallite-calyxes and thinning of associated skeletal elements, constituting a modification in skeleton architecture.We also detect increases in the organic matrix protein content of skeletons formed under lower pH.

View Article: PubMed Central - PubMed

Affiliation: 1] Marine Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, Monaco 98000, Monaco [2] Laboratoire Européen Associé 647 « BIOSENSIB », Centre Scientifique de Monaco- Centre National de la Recherche Scientifique, 8 Quai Antoine 1er, Monaco 98000, Monaco.

ABSTRACT
Ocean acidification causes corals to calcify at reduced rates, but current understanding of the underlying processes is limited. Here, we conduct a mechanistic study into how seawater acidification alters skeletal growth of the coral Stylophora pistillata. Reductions in colony calcification rates are manifested as increases in skeletal porosity at lower pH, while linear extension of skeletons remains unchanged. Inspection of the microstructure of skeletons and measurements of pH at the site of calcification indicate that dissolution is not responsible for changes in skeletal porosity. Instead, changes occur by enlargement of corallite-calyxes and thinning of associated skeletal elements, constituting a modification in skeleton architecture. We also detect increases in the organic matrix protein content of skeletons formed under lower pH. Overall, our study reveals that seawater acidification not only causes decreases in calcification, but can also cause morphological change of the coral skeleton to a more porous and potentially fragile phenotype.

No MeSH data available.


Related in: MedlinePlus

Organic matrix protein content of the coral skeletons in the four pH treatments.(one way ANOVA, n=6, F3,20=3.384, P<0.05). Data are means±s.e.m. Asterisk (*) indicates values that are significantly different for treatment with pH 8 (P<0.05).
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f5: Organic matrix protein content of the coral skeletons in the four pH treatments.(one way ANOVA, n=6, F3,20=3.384, P<0.05). Data are means±s.e.m. Asterisk (*) indicates values that are significantly different for treatment with pH 8 (P<0.05).

Mentions: Changes in skeleton morphology were accompanied by a significant increase in organic matrix (OM) proteins per gram of skeleton in corals from pH 7.2 versus pH 8 (Fig. 5). The increase in the ratio of OM proteins to gram of skeleton is not driven solely by the decrease in calcification, because, when OM per gram is converted to OM per cm3 using mean bulk density values (Fig. 1c), an increase in OM is still observed (30.60 μg cm−3 at pH 8 versus 34.16 μg cm−3 at pH 7.2). This finding is the first indication that ocean acidification causes an enrichment in OM incorporation in the coral skeleton and is also consistent with transcriptomic data from other coral species showing that the expression of certain OM protein genes are upregulated during acidification in coral juveniles24 and adults17.


Morphological plasticity of the coral skeleton under CO2-driven seawater acidification.

Tambutté E, Venn AA, Holcomb M, Segonds N, Techer N, Zoccola D, Allemand D, Tambutté S - Nat Commun (2015)

Organic matrix protein content of the coral skeletons in the four pH treatments.(one way ANOVA, n=6, F3,20=3.384, P<0.05). Data are means±s.e.m. Asterisk (*) indicates values that are significantly different for treatment with pH 8 (P<0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490415&req=5

f5: Organic matrix protein content of the coral skeletons in the four pH treatments.(one way ANOVA, n=6, F3,20=3.384, P<0.05). Data are means±s.e.m. Asterisk (*) indicates values that are significantly different for treatment with pH 8 (P<0.05).
Mentions: Changes in skeleton morphology were accompanied by a significant increase in organic matrix (OM) proteins per gram of skeleton in corals from pH 7.2 versus pH 8 (Fig. 5). The increase in the ratio of OM proteins to gram of skeleton is not driven solely by the decrease in calcification, because, when OM per gram is converted to OM per cm3 using mean bulk density values (Fig. 1c), an increase in OM is still observed (30.60 μg cm−3 at pH 8 versus 34.16 μg cm−3 at pH 7.2). This finding is the first indication that ocean acidification causes an enrichment in OM incorporation in the coral skeleton and is also consistent with transcriptomic data from other coral species showing that the expression of certain OM protein genes are upregulated during acidification in coral juveniles24 and adults17.

Bottom Line: Ocean acidification causes corals to calcify at reduced rates, but current understanding of the underlying processes is limited.Instead, changes occur by enlargement of corallite-calyxes and thinning of associated skeletal elements, constituting a modification in skeleton architecture.We also detect increases in the organic matrix protein content of skeletons formed under lower pH.

View Article: PubMed Central - PubMed

Affiliation: 1] Marine Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, Monaco 98000, Monaco [2] Laboratoire Européen Associé 647 « BIOSENSIB », Centre Scientifique de Monaco- Centre National de la Recherche Scientifique, 8 Quai Antoine 1er, Monaco 98000, Monaco.

ABSTRACT
Ocean acidification causes corals to calcify at reduced rates, but current understanding of the underlying processes is limited. Here, we conduct a mechanistic study into how seawater acidification alters skeletal growth of the coral Stylophora pistillata. Reductions in colony calcification rates are manifested as increases in skeletal porosity at lower pH, while linear extension of skeletons remains unchanged. Inspection of the microstructure of skeletons and measurements of pH at the site of calcification indicate that dissolution is not responsible for changes in skeletal porosity. Instead, changes occur by enlargement of corallite-calyxes and thinning of associated skeletal elements, constituting a modification in skeleton architecture. We also detect increases in the organic matrix protein content of skeletons formed under lower pH. Overall, our study reveals that seawater acidification not only causes decreases in calcification, but can also cause morphological change of the coral skeleton to a more porous and potentially fragile phenotype.

No MeSH data available.


Related in: MedlinePlus