WHOI Hosts Ocean Science Forum

The hosted a public forum at Wednesday evening, highlighting the serious but little-discussed issue of ocean acidification. The event shed light on the causes and consequences of acidification through an outdoor expo featuring exhibits and demonstrations, and presentations by WHOI scientists.

President and Director Susan Avery began the program by summarizing acidification, calling it “one of the greatest problems facing our ocean and our planet.”

Acidification is a byproduct of carbon dioxide emissions, largely the result of the mass burning of fossil fuels. When carbon dioxide is released into the atmosphere, some it remains there—to contribute to global warming—some is absorbed by the land, and some—about a quarter of the total—comes to rest in the earth's oceans.

“When you add more carbon dioxide to the ocean, its chemistry changes,” Avery said. “We as humans will certainly feel the effects of those changes.”

Scott Doney of WHOI's Marine Chemistry and Geochemistry department explained those changes. When carbon is added to water, it results in carbonic acid. During the process, hydrogen atoms are released, and carbonate ions are removed, raising the water's pH (making it more acidic), and depriving many marine animals of a compound central to their existence, calcium carbonate. Without enough calcium carbonate, many coral, mollusks, squids, crustaceans, and other species can't build the shells and other structures they need to survive.

While not all marine species depend directly on calcium carbonate, many are linked, perhaps inextricably, to the ones that do. For example, pteropods—tiny mollusks which have evolved into an astounding variety of shapes—are consumed by an enormous number of larger animals, earning them the nickname “The popcorn of the sea.” Along with other tiny creatures such as shell-forming plankton, Doney said, “they're an important species at the base of the food web.” If the popcorn is taken off the menu, many animals will feel the impact.

Anne Cohen of the Geology and Geophysics department discussed another species whose existence is indispensable for a whole host of others. “Coral reefs are far more than just tourist destinations,” she said. Though they cover less than one percent of the seafloor, coral reefs host fully one quarter of all ocean life, including the same proportion of all fish consumed by humans. They also provide important protection against storms to coastal areas.

As acidification increases, coral will find it difficult to produce the massive structures so important to the ocean ecosystem. Cohen and others are already at work searching for populations of coral that have managed to adapt to the increased acidification that occurs naturally in certain areas, and to secure protection for them so they can be studied, and their secrets unlocked.

Sarah Cooley of the Marine Chemistry and Geochemistry department discussed the methods scientists are developing to understand and mitigate acidification's impact on humans. One way to quantify the potential costs is the idea of “ecosystem services,” which Cooley explained as “basically what nature provides us for free.” If acidification proceeds unchecked, Cooley said, humans may have to radically revise what they can expect from nature.

While acidification may strike many as yet another intractable environmental problem, Cooley emphasized that steps can be taken, at all levels of society. “The solutions have to be big, and they have to be small,” she said. “They have to be global, and they have to be local... We can all do a little bit, because we've all contributed a little bit to it.”