Troubled Waters

摘要

The world's oceans are heating up. And like a bottle of pop left out in the sun, they're going flat. Except instead of carbon dioxide, they're losing oxygen. As with most liquids, waters ability to dissolve oxygen largely depends on temperature. The warmer the water, the less oxygen it can hold. Though oxygen-starved or hypoxic zones have always existed, warmer waters may be causing these zones to expand, according to new research published in the journal Science. The study, led by Lothar Stramma at the University of Kiel in Germany, addressed changes in different regions of the oceans, and found that oxygen levels in tropical oceans hundreds of feet below the surface have declined over the past 50 years. These low oxygen areas are generally found in the Pacific, Atlantic and Northern Indian Ocean, according to coauthor Gregory C. Johnson, an oceanographer with the federal Pacific Marine Environmental Laboratory in Seattle. Though located deep within the ocean, these oxygen-minimum zones have the ability to affect coastal areas.