Global Warming May Shift Marine Habitats as Seas Warm with Less Oxygen

As temperatures warm, marine habitats are likely to experience some changes. Scientists have found that warmer, lower-oxygen oceans will shift marine habitats.

"If your metabolism goes up, you need more food and you need more oxygen," said Curtis Deutsch, the lead author of the new study, in a news release. "This means that aquatic animals could become oxygen-starved in the warmer future, even if oxygen doesn't change. We know that oxygen levels in the ocean are going down now and will decrease more with climate warming."

In this latest study, the researchers focused on four Atlantic Ocean species whose temperature and oxygen requirements are well known. The study included Atlantic cod that live in the open ocean, Atlantic rock crab in coastal waters, sharp snot seabream in the subtropical Atlantic and Mediterranean, and common eelpout that lives in shallow waters in high northern latitudes.

The researchers used climate models to see how the projected temperature and oxygen levels would affect the four species by 2100. If current emissions continue, it's estimated that the near-surface ocean will warm by several degrees Celsius by the end of this century, and seawater would hold 5 to 10 percent less oxygen than it does now.

It turns out that habitats in general would shift. Future rock crab habitat would be restricted to shallower water, hugging the more oxygenated surface. In addition, the equator region of all four species would become uninhabitable. Viable habitats shifting away from the equator would displace from 14 to 26 percent of the current ranges.

"For aquatic animals that are breathing water, warming temperatures create a real problem of limited oxygen supply versus elevated demand," said Raymond Huey, co-author of the new study, in a news release. "This simple metabolic index seems to correlate with the current distributions of marine organisms, and that means that it gives you the power to predict how range limits are going to shift with warming."

The findings are published in the journal Science.

Related Stories

Climate Geoengineering May be the Only Way to Save Coral Reefs from Warming Seas

Climate Change May Cause More Powerful but Less Frequent Hurricanes

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).