Alaskan King Crab, Many Other Seafoods at Risk From Global Carbon Dioxide Emissions
August 1, 2014
The future of Alaska's fisheries, and by extension its seafood industry, is at risk from the carbon dioxide emissions humans pump into the atmosphere every day from our cars, factories and power plant smokestacks, according to a new study.
That's because the oceans are becoming more acidic from absorbing all of that CO2, much of which comes from the burning of fossil fuels like coal, oil and natural gas. Rising ocean acidification can harm both commercial and subsistence fisheries and the small communities that rely on them, according to the NOAA-led study, which was published Tuesday in the online journal Progress in Oceanography.
Changes in ocean chemistry could make it harder for mollusks and other small creatures to build and keep their skeletons or shells, the researchers found. Previous studies have shown red king crab and tanner crab grow more slowly in more acidic water and that red king crab died in highly acidified conditions.
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Communities in southeast and southwest Alaska face the highest risk from ocean acidification because of their reliance on fishing, relatively lower income levels and fewer job alternatives than other parts of Alaska, the report states. For communities with high food and energy costs, ocean acidification could be another hit, the research says.
According to NOAA, Alaska's high-latitude coastal waters are more vulnerable to acidification because cold water can absorb more carbon dioxide. Circulation patterns also bring more acidic deep-ocean water to the surface, the agency said.
Co-lead author of the study, NOAA oceanographer Jeremy Mathis, said the goal was to try to quantify the potential risk and impacts from ocean acidification, a question that's come up in meetings with fishermen, villages and communities but one he's never had a good answer for.
While direct, harmful impacts aren't showing up yet, the ocean is changing quickly, he said. Oceans are about 30 percent more acidic today than they were at the start of the Industrial Revolution, he said. If fossil fuels continue to be burned at the current rate, pH levels could drop significantly by the end of the century, said Mathis, who is also director of an ocean acidification research center at the University of Alaska Fairbanks.
"We could have a 300 percent greater change between now and the end of the century than we have in the past 250 years combined," he said. "So the rate of change is what's accelerating."
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Mathis said lab studies have shown a low level of tolerance for acidification in crab, but those impacts haven't been seen in the wild yet. As the oceans change, there are some who believe species will adapt or new organisms will emerge, and that could happen, he said. But acidification also could change population dynamics, he said.
"In a place like the Bering Sea, where a billion-dollar industry has been built around a few species of crabs, then that's where we really start to worry. It's something we're going to have to pay very close attention to," Mathis said.
As an area of further study, Mathis said he would like to be able to quantify the potential financial impacts of the changes.