A new study shows that deep-sea coral communities living in acidified waters are weaker and more likely to crumble than the same corals living in less acidic conditions.
Under normal conditions, live deep-sea corals build on the skeletons of dead corals, creating a complex, three-dimensional structure that provides habitat for a variety of marine organisms. If the water acidifies, the skeletal material of the dead corals becomes more porous, weakens, and eventually crumbles. The live coral still grows, but without the foundation of the dead corals, the reef structure is less complex and less capable of supporting biodiversity.
The study is based on samples and observations of Lophelia pertusa corals living at different depths off the coast of California’s Channel Islands and off the coast of western Scotland. The research team, which includes NCCOS’s Dr. Peter Etnoyer, analyzed coral samples over time to better understand the skeletal weakening mechanisms under increasing acidity. The team observed rapid weakening, with a result similar to the effect of osteoporosis seen in aging human bones. Interestingly, the study could help inform efforts to model the onset and progression of osteoporosis in humans.
Project results will help natural resource managers better quantify when deep-sea coral communities in their jurisdictions might lose their complexity and biodiversity as a result of ocean acidification. By 2100, it is projected that increasing ocean acidification will cause the roughly 95 percent of deep-sea coral reefs around the world currently exhibiting complex structure to drop to about 30 percent.