UW News

November 21, 2016

Ocean acidification study offers warnings for marine life, habitats

Acidification of the world’s oceans could drive a cascading loss of biodiversity in some marine habitats, according to research published Nov. 21 in Nature Climate Change.

The work by biodiversity researchers from the University of British Columbia, the University of Washington and colleagues in the U.S., Europe, Australia, Japan and China, combines dozens of existing studies to paint a more nuanced picture of the impact of ocean acidification.

Sea grass beds, like these off the coast of British Columbia, Canada, might buffer the impacts of ocean acidification

Sea grass beds, like these off the coast of British Columbia, Canada, might buffer the impacts of ocean acidification.Christopher Harley/University of British Columbia

While most research in the field focuses on the impact of ocean acidification on individual species, the new work predicts how acidification will affect the living habitats such as corals, seagrasses and kelp forests that form the homes of other ocean species.

“Not too surprisingly, species diversity in calcium carbonate-based habitats like coral reefs and mussel beds were projected to decline with increased ocean acidification,” said lead author Jennifer Sunday, a UBC zoologist and biodiversity researcher. Species that use calcium carbonate to build their shells and skeletons, like mussels and corals, are expected to be particularly vulnerable to acidification.

“The more complex responses are those of seagrass beds that are vital to many fisheries species. These showed the potential to increase the number of species they can support, but the real-world evidence so far shows that they’re not reaching this potential. This highlights a need to focus not only on individual species, but on how the supportive habitat that sets nature’s stage responds and interacts to climate change.”

The researchers combined data and observations from 10 field studies that measured the impact of underwater volcanic vents, which release carbon dioxide and mimic the conditions of future ocean acidification, on the density of habitat-forming species. They combined that data with 15 studies looking at how changes in habitat typically impact local species to make their predictions.

“This work demonstrates the value of international collaborations to address a problem that’s global in scope and crosses boundaries between distinct habitats and ecosystems,” said co-author Terrie Klinger, professor and director of the UW’s School of Marine and Environmental Affairs who also co-directs the Washington Ocean Acidification Center. “We can begin to test predictions with data from different locations to better understand likely ecosystem responses to ocean acidification.”

Coral ecosystems, like these pictured off the coast of Mexico, will be hit hard as the oceans become more acidic

Coral ecosystems, like these pictured off the coast of Mexico, will be hit hard as the oceans become more acidic.Christopher Harley/University of British Columbia

The researchers focused their study on the impact of ocean acidification on coral reefs, mussel beds, kelp forests and seagrass meadows that form the homes of thousands of marine species. They used observations of altered habitats around the world to project how changes in these habitats brought on by ocean acidification will impact the number of species that each habitat can support.

The researchers were able to test their predictions against real-world data from two sites: a coral reef near Papua New Guinea and a group of seagrass beds in the Mediterranean. In the case of the coral reef, the diversity and complexity of marine life in the area decreased as acidification increased. Despite predictions that the seagrass beds would fare well under increased levels of carbon dioxide, no increases in biodiversity was observed.

Because there are so few test sites to use to directly test the model, the authors want to expand on the approach.

“We’ve known for a while that there will be big losers and some winners with climate change,” said UBC marine ecologist Christopher Harley, senior author on the paper. “For example, in the Pacific Northwest, the number of medium to large-sized edible saltwater mussels is likely to decrease as the chemistry of our oceans changes, and this is bad news for the hundreds of species that use them for habitat.”

The study was funded by the Peter Wall Institute for Advanced Studies, the National Science Foundation and the National Science and Engineering Research Council of Canada.


For more information, contact Klinger at tklinger@uw.edu or 206-685-2499.

This was adapted from a UBC news release.