Seagrass can provide localized protection against ocean acidification

Brooks Hays UPI 31 Jul 18;

July 31 (UPI) -- Seagrass could serve as a local buffer against ocean acidification, protecting vulnerable species against rising levels of carbonic acid.

In addition to providing food and shelter to a variety of marine organisms, seagrass also absorbs carbon dioxide as it performs photosynthesis. Researchers with the Carnegie Institution for Science designed to models to measure whether a seagrass meadow's carbon uptake abilities could lower pH levels.

The models accounted for grass density, photosynthetic activity, water depth, currents and a variety of other factors. The results, detailed in the journal Ecological Applications, suggests seagrass can have a small, local effect on ocean acidity.

"Local stakeholders, such as California's shellfish industry, want to know whether seagrass meadows may help to counteract ocean acidification," Carnegie researcher David Koweek said in a news release. "Our results suggest that seagrass meadows along the California coast will likely offer only limited ability to counteract ocean acidification over long periods of time."

Though scientists found seagrass was unlikely to offer longterm protection, they did show seagrass meadows can offer stronger, short-term benefits during low tide and during the day when photosynthetic activity peaks.

Carbonic acid is corrosive and prevents shellfish from forming their shells out of calcium carbonate. The latest research suggests shellfish could potentially take advantage of the short-term protections offered by sea grass.

"We are starting to understand that some marine organisms, such as blue mussels, are actually able to shift the time of day in which they do most of their calcification," Koweek said. "If other organisms are able to do the same, then even brief windows of significant ocean acidification buffering by seagrass meadows may bring substantial benefits to the organisms that live in them."

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The best way to fight ocean acidification, scientists insist, is to drastically curb the amount of carbon dioxide being released into the atmosphere. But conserving sea grass could help, too.

"Although our results indicate that seagrass meadows along the California coast are not likely to offer long-term buffering to fight ocean acidification, their enduring role as habitat for marine organisms, protectors against sea level rise, and magnets of biodiversity should be more than enough reason to restore and protect these iconic ecosystems," Koweek said.