New research predicted how warming ocean waters and less available oxygen will change marine habitats.
The findings suggest the rising temperature of the water will speed up marine animals' metabolic need for oxygen, but there will also be less oxygen available to them, the University of Washington reported. The study's researchers believe this will push animal populations away from the equator.
"If your metabolism goes up, you need more food and you need more oxygen," said lead author Curtis Deutsch, a UW associate professor of oceanography. "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."
The study focused on four Atlantic Ocean species: "Atlantic cod that live in the open ocean; Atlantic rock crab that live in coastal waters; sharp snout seabream that live in the subtropical Atlantic and Mediterranean; and common eelpout, a bottom-dwelling fish that lives in shallow waters in high northern latitudes."
The team used climate models to predict how changes in temperature and marine oxygen levels by the year 2100 would influence these animals' ability to meet their energy needs. They determined if current emissions continue, the near-surface ocean will warm by several degrees Celsius and the water will hold between5 and 10 percent less oxygen than it does today. In this scenario, rock crabs would be restricted to shallower water because it would be more oxygenated, and between 14 and 26 percent of the range of all four species would be uninhabitable.
"For aquatic animals that are breathing water, warming temperatures create a real problem of limited oxygen supply versus elevated demand," said co-author Raymond Huey, a UW professor of biology who has studied metabolism in land animals and in human mountain climbers. "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 were published in a recent edition of the journal Science.