Chem Lunch Seminar, 5 Jun 2020

Friday, June 05, 2020

Chemical Oceanography Lunch Seminar
Resiliance to ocean acidification in cold-water corals has a cost

Alex Gagnon
UW School of Oceanography

1:30 P.M., via Zoom
Zoom meeting link:


Coral skeletal growth is sensitive to environmental change and may be adversely impacted by an acidifying ocean. However, physiological processes can also buffer biomineralization from external conditions, providing apparent resilience to acidification in some species. These same physiological processes affect skeletal composition and can impact paleoenvironmental proxies. Understanding the mechanisms of coral calcification is thus crucial for predicting the vulnerability of different corals to ocean acidification and for accurately interpreting coral-based climate records. Here, using boron isotope (δ11B) measurements on cultured cold-water corals together with a geochemical model of biomineralization, I explain fundamental features of coral calcification and its sensitivity to environmental change. This approach shows that apparent resilience to ocean acidification has a hidden energetic cost such that calcification becomes less efficient in a more acidic ocean. I also resolve why boron isotopes, one of the most widely used proxies for past ocean pH, is such a useful proxy across a range of calcifiers, even when calcifying fluid pH differs from seawater.

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