r. carey gersten

Oxygen-deprived areas in the world’s oceans usually found in deeper water are moving up to offshore areas and threatening coastal marine ecosystems by spurring the die-off of some species and overpopulation of others

By Michael Tennesen | Scientific American | February 23, 2010

A plague of oxygen-deprived waters from the deep ocean is creeping up over the continental shelves off the Pacific Northwest and forcing marine species there to relocate or die. Since 2002 tongues of hypoxic, or low-oxygen, waters from deeper areas offshore have slipped into shallower near-shore environments off the Oregon coast, although not close enough to be oxygenated by the waves. The problem stems from oxygen reduction in deep water, a phenomenon that some scientists are observing in oceans worldwide, and that may be related to climate change.

The hypoxic seawater is distinct from the well-known “dead zones” that form at the mouths of the Mississippi and other rivers around the world. Those areas result from agricultural runoff, which lead to algae blooms that consume oxygen. Rather, the Pacific Northwest problem is broader and more mysterious.

Read on: http://www.scientificamerican.com/article.cfm?id=low-oxygen-ocean-coastal