Coral calcification

Assembled from 17 blocks · 2 evidence · 8 related

1. Story
2. The process by which the polyp precipitates aragonite from seawater at the base of its tissue, in a thin calcifying fluid space that it actively controls. The coral raises the pH and the carbonate ion concentration of that space above ambient seawater by pumping protons out, which is what makes precipitation thermodynamically favourable in water that would not spontaneously produce it. The energy for that pumping comes substantially from the symbionts, which is why calcification is light-enhanced: rates measured in daylight are several times those measured in the dark, and a bleached colony calcifies very little. Two consequences follow that a reader should hold together. Calcification is not merely correlated with the symbiosis, it is powered by it. And because the process depends on the ambient carbonate chemistry the coral is working against, it becomes more expensive as that chemistry changes.
3. Knowledge
4. Coral calcification
5. Ocean acidification
6. Connections
7. Zooxanthellae (Symbiodiniaceae)
8. Ocean acidification
9. Reef carbonate budget
10. Symbiont shuffling and thermal tolerance
11. A measured decline in Great Barrier Reef coral calcification is published
12. Coral calcification
13. Reef carbonate budget
14. A measured decline in Great Barrier Reef coral calcification is published
15. Evidence
16. Zooxanthellae translocate a large majority of fixed carbon to the coral host, which is what allows reef-building corals to thrive in nutrient-poor tropical water. V55 verification basis: not consulted in this session; the paper was identified and its central finding stated from the producing model's knowledge of the symbiosis literature. Page range not given rather than invented.
17. Calcification in massive Porites on the Great Barrier Reef declined by about fourteen per cent from 1990, a change the authors described as without precedent in the preceding four centuries of the skeletal record. V55 verification basis: not consulted; the figure is stated from the producing model's knowledge. This result has been the subject of subsequent methodological debate that could not be reviewed here.