Cohen Lab

Impacts of Ocean Acidification

Toward Predicting the Impact of Ocean Acidification on Net Calcification by a Broad Range of Coral Reef Ecosystems: Identifying Patterns and Underlying Causes

PI: Anne Cohen (Woods Hole Oceanographic Institution) Co-PIs Steven Lentz and Kathryn Shamberger (Woods Hole Oceanographic Institution)

Coral reefs exist because reef calcifying organisms produce calcium carbonate faster than it can be eroded by the sea, or by boring organisms. Today, rates of calcium carbonate accretion only barely exceed rates of dissolution, and as a result coral reefs grow very slowly, if at all.  Ocean acidification threatens to tip the balance between reef accretion and erosion, by slowing rates of calcium carbonate production and accelerating rates of natural erosion. However, we know very little about how this might occur, when it might occur for different reef systems in different parts of the world, and which reef systems are most vulnerable.  To date, much of our understanding of the impact of ocean acidification on coral reef calcification comes from laboratory manipulation experiments with single organisms. By comparison, there is a paucity of in situ data describing the sensitivity of coral reef ecosystems to changes in calcium carbonate saturation. Emerging evidence suggests there may be critical differences between the calcification response of organisms in culture and the net calcification response of a coral reef ecosystem, to the same degree of change in calcium carbonate saturation. In the majority of cases, the sensitivity of net reef calcification to changing calcium carbonate saturation is more severe than laboratory manipulation experiments predict. Thus, we propose that accurate predictions of the response of coral reef ecosystems to 21st century ocean acidification will depend on a robust characterization of ecosystem-scale responses and an understanding of the fundamental processes that shape them.  Our project expands the currently sparse dataset of ecosystem-scale observations at four strategically placed reef sites, enabling us to test a series of hypotheses related to the impact of ocean acidification on net calcification of the whole reef ecosystem.

Funding for this research is provided by The National Science Foundation (NSF #OCE-1220529)

 

Last updated: June 17, 2013