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Oceans In Crisis Promote Research

Ocean acidification opens doors for research on marine life, development of sensors, and efforts to mitigate adverse effects

by D. Rachael Bishop
July 21, 2014 | A version of this story appeared in Volume 92, Issue 29

Image showing projected pH of oceans in 2100, assuming no change in human CO2 emission, compared with ocean pH in 1850.
Credit: International Geosphere-Biosphere Programme/Intergovernmental Oceanographic Commission/ Scientific Committee on Oceanic Research
This projected level of ocean pH in 2100 assumes the world makes no changes in CO2 emissions. The pH of the oceans in 1850, when the fossil-fueled Industrial Revolution was just beginning, is shown in the inset. Orange lines outline important fisheries.

The oceans are acidifying, threatening marine life and the well-being of humans who depend on food from the sea. Policymakers are turning to scientists for insights and answers about this predicament. Chemists, chemical engineers, and biogeochemists, in particular, have rapidly growing opportunities to explore new scientific disciplines, develop new technologies, and inform global policy and action.

The world’s oceans, especially the colder waters of the Arctic and Southern Oceans, absorb 27% of atmospheric carbon dioxide, Carol Turley, a biogeochemist at the Plymouth Marine Laboratory in the U.K., told an international conference on oceans held last month by the U.S. Department of State in Washington, D.C. This 27% includes CO2 that has been emitted from the burning of fossil fuels. Carbon dioxide mixed with seawater produces carbonic acid, which is steadily driving the ocean’s pH lower.

“The global ocean is now 30% more acidic than at the beginning of the Industrial Revolution,” Turley told the conference, which drew attendees from nearly 90 nations. “It’s happening at such a rapid rate; it’s really a concern.”

This global change offers enormous research and technology development opportunities, said Scott C. Doney, senior scientist and director of the Woods Hole Oceanographic Institution’s Ocean & Climate Change Institute.

“Particularly from the chemistry side, there’s a lot of fundamental knowledge needed,” Doney told the conference. This includes greater understanding of the molecular structure of marine species’ shells. A key building block for shells or skeletons of many species—including corals, shellfish, and pelagic snails—is aragonite. Ocean acidification is reducing the concentration of aragonite, one of the main mineral forms of calcium carbonate, in seawater.

Credit: U.S. State Department
Kerry speaks with DiCaprio, who pledged $7 million to support ocean protection projects.
Secretary of State John Kerry (left) and actor Leonardo DiCaprio at a conference on oceans, June 2014.
Credit: U.S. State Department
Kerry speaks with DiCaprio, who pledged $7 million to support ocean protection projects.

Ocean acidification research has practical implications. Shellfish farmers off the coast of Oregon and Washington first noticed dramatic oyster larvae die-off beginning in 2006, said Bill Dewey, of Taylor Shellfish Farms, of Shelton, Wash. The problem reached a critical level in 2008 and 2009, when two of four commercial hatcheries in the Pacific Northwest region lost 75% of their oyster larvae, he said.

The cause of this situation remained a puzzle for a couple of years. Water chemistry studies conducted by the U.S. government and universities provided the answer.

“We learned it was the changing seawater chemistry,” Dewey said. Waters that are high in CO2 and low in calcium carbonate ions are stored deep in the Pacific Ocean. “When we get northerly winds along the U.S. West Coast, these waters come to the surface—upwell—into our estuaries and then we pump them into our hatcheries.” These relatively more acidic waters interfere with the ability of oyster larvae, which are free-floating plankton, to form shells.

Now, Taylor Shellfish closely monitors the water chemistry. When lower-pH water upwells, the company adds sodium carbonate or, if need be, isolates its oyster hatcheries from incoming seawater.

Ocean chemistry research is only one of the scientific opportunities related to marine acidification. For example, the XPRIZE Foundation is sponsoring a $2 million public competition to develop two sensors: a device to make long-term measurements especially in deep water and a second sensor to evaluate coastal runoff and nutrient pollution. The foundation seeks radical breakthroughs to benefit humanity and inspire new industries.

Development of a deep-water sensor would be a huge benefit for the National Oceanic & Atmospheric Administration’s (NOAA) Array for Real-time Geostrophic Oceanography (called Argo) fleet of 3,500 free-drifting floats, said Margaret Leinen, director of Scripps Institution of Oceanography. These floats sink and bob back to the surface, radioing data via satellite back to laboratories. Currently, 90% of the Argo floats measure salinity and temperature, but only 10% also have pH sensors. An affordable pH sensor that can withstand open-ocean conditions would be a boon for these highly mobile floats.

Ocean acidification in the Arctic opens up a host of additional research topics. Loss of sea ice as a result of global warming is leading to more open water and increased gas exchange between the ocean and atmosphere. Reduced sea ice also means the Arctic Ocean absorbs more sunlight, which leads to the formation of large plankton blooms, said Jeremy Mathis, a marine chemist with NOAA’s Pacific Marine Environmental Laboratory. Scientists need to probe how ocean acidification is affecting these plankton and other organisms that support Arctic food webs, he said.

“A juicy area of science to look at is Pelagibacter ubique,” a bacterium that is among the most abundant organisms in the ocean, Scripps’s Leinen said. Study of how acidification affects P. ubique is important because this organism significantly impacts the carbon cycle in the oceans, she explained.

The oceans conference, held June 16–17, was convened by U.S. Secretary of State John Kerry and was attended by scientists, representatives of fishing interests, policymakers, environmental activists, and heads of state. They developed a comprehensive plan on oceans that will be submitted to the United Nations.

Attendees also pledged more than $1.8 billion to protect 3 million km2 of the ocean, limit commercial fishing, and pursue ocean acidification research. Three large financial offerings led the pack.

Norwegian Minister of Foreign Affairs Børge Brende pledged $1 billion for climate change mitigation and adaptation programs. “As a nation of seafarers and fishermen, Norwegians have lived off the ocean and in close contact with the ocean throughout history,” he said. “The only way to fight … the global-scale problem of ocean acidification … is through a reduction in the global level of CO2 emissions.”

“The National Oceanic & Atmospheric Administration has pledged $9 million for long-term ocean acidification observations and to make data publicly available via the Web,” said Elizabeth (Libby) Jewett, director of NOAA’s Ocean Acidification Program.

Actor Leonardo DiCaprio, who pledged $7 million from his foundation, said ocean acidification is a personal concern. “Before I wanted to be an actor, I wanted to be a marine biologist.” DiCaprio said he has seen the decline of areas around the world where he has dived during the past 20 years. “What once had looked like an endless underwater utopia is now riddled with bleached coral reefs and massive dead zones.”

Kerry said the world needs a better understanding of ocean acidification caused by CO2 emissions. “We ought to be able to know where it’s happening, how quickly it’s happening, so we can find the best way to slow it down. The connection between a healthy ocean and life itself for every single person on Earth cannot be overstated.”

D. Rachael Bishop is manager of public policy communications at the American Chemical Society.


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