The 3D maps may help researchers track and predict the ocean’s response to climate change. By Jennifer Chu | MIT News Office Life is teeming nearly everywhere in the oceans, except in certain pockets where oxygen naturally
The 3D maps may help researchers track and predict the ocean’s response to climate change.Life is teeming nearly everywhere in the oceans, except in certain pockets where oxygen naturally plummets and waters become unlivable for most aerobic organisms. These desolate pools are “oxygen-deficient zones,” or ODZs. And though they make up less than 1 percent of the ocean’s total volume, they are a significant source of nitrous oxide, a potent greenhouse gas.
From these maps, the researchers estimated the total volume of the two major ODZs in the tropical Pacific, more precisely than previous efforts. The first zone, which stretches out from the coast of South America, measures about 600,000 cubic kilometers — roughly the volume of water that would fill 240 billion Olympic-sized pools. The second zone, off the coast of Central America, is roughly three times larger.
Over the last 40 years, research cruises have explored these regions by dropping bottles down to various depths and hauling up seawater that scientists then measure for oxygen. Scientists have attempted to use these sensor data to estimate the true value of oxygen concentrations in ODZs, but have found it incredibly tricky to convert these signals accurately, particularly at concentrations approaching zero.
“We can now see how the distribution of anoxic water in the Pacific changes in three dimensions,” Babbin says. Such observations of the tropical Pacific’s oxygen-deficient zones are more detailed than what’s been measured to date.