Effects of Acidification on Cold-Water Corals

While most people think of shallow water reefs when they think of corals, the deep-sea hosts an expansive habitat of corals far beneath the surface. These cold-water coral reefs can support a diversity of life and form important fishery habitat and nursery grounds. 


Deep-sea surveys conducted by NOAA from 2012-2015 in the Mid-Atlantic, discovered an abundance of gorgonian sea fans and bamboo corals. In January 2017 the new Frank R. Lautenberg Deep-Sea Coral Protection Area came in to effect, with approximately 40,000 square miles of protection in the deep-sea from offshore New York to Virginia. This area hosts a diversity of cold-water corals that are now protected from many types of commercial bottom fishing gear. 

The deep-sea is not immune to the effects of acidification. In these areas, there are lower concentrations of the calcium carbonate building blocks corals use to make their skeletons and ocean acidification is expected to reduce this concentration, making it harder for corals to grow and repair themselves. 


There have been few conclusive studies on the effects of acidification on cold-water corals and effects often vary by species. While some research indicates that acidification may impact cold-water stony corals, these reef-building species are not abundant in the Mid-Atlantic. The effects of acidification on most cold-water gorgonians and bamboo corals are unknown, but studies of shallow water species suggest they may be resistant to these changes in seawater chemistry. 

References

Gómez, CE, Paul, VJ, Ritson-Williams, R. et al. (2015) Responses of the tropical gorgonian coral Eunicea fusca to ocean acidification conditions. Coral Reefs 34: 451. doi:10.1007/s00338-014-1241-3
Hennige, SJ, Wicks, LC, Kamenos, NA, Perna, G, Findlay, HS, and Roberts, JM. (2015). Hidden impacts of ocean acidification to live and dead coral framework. Proc. R. Soc. B 282, 1–10. doi: 10.1098/rspb.2015.0990