Dead Zone LIkely To Return To Oregon Coast For Third Year Out Of Four

[hatrack]

The Pacific Ocean off of Oregon has experienced a die-off of birds, declining fisheries and wildly fluctuating conditions in the past few months, and has set the stage for another hypoxic "dead zone" like those of 2002 and 2004, according to experts at Oregon State University.

This is the third year in the past four that has demonstrated significantly unusual ocean events, the researchers say, a period unlike any on record. The events have not all been the same. This year's ocean behavior is particularly bizarre, and there is no proof what is causing it. But extreme variability such as this, OSU researchers say, is consistent with what scientists believe will occur as a result of global warming.

"All the climate models predict increased variability associated with global climate change," said Jane Lubchenco, the Wayne and Gladys Valley Professor of Marine Biology at OSU. "And there is no doubt that what is going on right now off Oregon is not normal." In May and June when seasonal "upwelling" events should have begun that bring cold, nutrient-rich water to the surface, the ocean was 8 to 11 degrees warmer than usual and had chlorophyll levels, a measure of productivity, about one-fifth to one-sixth of normal, said Lubchenco. As a result, scientists were observing dead birds on beaches, major declines in fisheries, and other symptoms of a marine food web that was literally starving.

Then in mid-July, it appears that a normal, strong upwelling event finally began, bringing cool water and lots of nutrients. The resulting intense bloom of microscopic plants coupled with low oxygen levels near the ocean floor set the stage for another "dead zone" event this year. "The nearshore ocean right now looks like a brown pea soup," said Lubchenco, a director of the Partnership for Interdisciplinary Studies of Coastal Oceans, a pioneering research cooperative on the West Coast. "Just in the past couple weeks there was a spectacular bloom of diatoms."

Some upwelling is essential and desirable. But too much can lead to a glut of phytoplankton which in turn decay and, in combination with the right types of winds and currents, lead to over-consumption of the remaining oxygen in the water and a die-off of marine life.

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