Phosphorus enrichment hampers the development of juvenile coral by directly inhibiting biomineral skeleton elongation
Abstract
Coral reef degradation resulting from various types of stress such as excessive nutrient enrichment in and inflow of gravel into coastal waters is of increasing global concern. In general, tropical and subtropical seawaters are poor in nutrients and thus oligotrophic. Therefore, the above-mentioned stresses result in the decline of environments favorable to coral growth. Especially inorganic phosphates have been considered to possibly inhibit the formation of coral skeleton. Despite many studies about the effects of nutrients on coral, a clear consensus on how nutrients deteriorative effect on the coral has not been established. Recently, we found that biogenic polyamines can react with carbon dioxide (CO2) and accelerate an aragonite formation of CaCO3in seawater. In this study, we examined that the effect of phosphates and nitrates on in vitro the aragonite formation of CaCO3by using biogenic polyamines and in vivo aragonite formation of skeletons in juvenile coral of Acropora digitifera, showing that phosphates clearly inhibited both in vitro and in vivo CaCO3formations at similar concentrations. In contrast, nitrates inhibited neither in vitro aragonite formation of CaCO3nor in vivo aragonite formation of juvenile coral skeletons. These findings indicate that phosphates have a detrimental effect on bioinorganic coral calcification. Furthermore, the findings that phosphate enrichment promotes the inhibiting effect on skeleton formation led us to conclude that enriched phosphate is adsorbed to the skeleton surface and inhibit normal development skeleton of juvenile coral. Calcareous sediment could be a source of phosphate in coastal environments. The juvenile coral, a sessile animal, will be strongly affected by phosphate dissolved from the calcareous sediment in coastal environments.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP41C1564I
- Keywords:
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- 1039 Alteration and weathering processes;
- GEOCHEMISTRY;
- 1051 Sedimentary geochemistry;
- GEOCHEMISTRY;
- 4217 Coastal processes;
- OCEANOGRAPHY: GENERAL;
- 4912 Biogeochemical cycles;
- processes;
- and modeling;
- PALEOCEANOGRAPHY