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| Titel |
Relative roles of endolithic algae and carbonate chemistry variability in the skeletal dissolution of crustose coralline algae |
| VerfasserIn |
C. Reyes-Nivia, G. Diaz-Pulido, S. Dove |
| 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 ; 11, no. 17 ; Nr. 11, no. 17 (2014-09-01), S.4615-4626 |
| Datensatznummer |
250117571
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| Publikation (Nr.) |
 copernicus.org/bg-11-4615-2014.pdf |
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| Zusammenfassung |
| The susceptibility of crustose coralline algae (CCA) skeletons to
dissolution is predicted to increase as oceans warm and acidify. Skeletal
dissolution is caused by bioerosion from endolithic microorganisms and by
chemical processes associated with undersaturation of carbonate minerals in
seawater. Yet, the relative contribution of algal microborers and seawater
carbonate chemistry to the dissolution of organisms that cement reefs under
projected pCO2 and temperature (pCO2-T) scenarios have not been
quantified. We exposed CCA skeletons (Porolithon onkodes) to four pCO2-T treatments
(pre-industrial, present-day, SRES-B1 "reduced" pCO2, and
SRES-A1FI "business-as-usual" pCO2 emission scenarios) under natural light
cycles vs. constant dark conditions for 8 weeks. Dissolution rates of
skeletons without photo-endoliths were dramatically higher (200%) than
those colonized by endolithic algae across all pCO2-T scenarios. This
suggests that daytime photosynthesis by microborers counteract dissolution
by reduced saturation states resulting in lower net erosion rates over
day–night cycles. Regardless of the presence or absence of phototrophic
microborers, skeletal dissolution increased significantly under the spring
A1FI "business-as-usual" scenario, confirming the CCA sensitivity to
future oceans. Projected ocean acidity and temperature may significantly
disturb the stability of reef frameworks cemented by CCA, but surficial
substrates harbouring photosynthetic microborers will be less impacted than
those without algal endoliths. |
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