Dramatic expansion of dead zones in the oceans

(University of Copenhagen) Unchecked global warming would leave ocean dwellers gasping for breath. Dead zones are low-oxygen areas in the ocean where higher life forms such as fish, crabs and clams are not able to live. A team of Danish researchers have now shown that unchecked global warming would lead to a dramatic expansion of low-oxygen areas zones in the global ocean by a factor of 10 or more. The findings are published in the scientific journal Nature Geoscience. Professor Gary Shaffer of the Niels Bohr Institute, University of Copenhagen, who is the leader of the research team at the Danish Center for Earth System Science (DCESS), explains that "such expansion would lead to increased frequency and severity of fish and shellfish mortality events, for example off the west coasts of the continents like off Oregon and Chile". … He adds that "if, as in many climate model simulations, the overturning circulation of the ocean would greatly weaken in response to global warming, these oxygen minimum zones would expand much more still and invade the deep ocean." Extreme events of ocean oxygen depletion leading to anoxia are thought to be prime candidates for explaining some of the large extinction events in Earth history including the largest such event at the end of the Permian 250 million years ago. … Nature Geoscience Advanced Online Publication: http://www.nature.com/ngeo/journal/vaop/ncurrent/index.html