October 9, 2009

Pacific Ocean dead patches here to stay, say scientists.

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For the eighth consecutive year, Oregon’s coastal waters  have experienced abnormally low late-summer oxygen levels — often resulting in massive biological “dead zones” — and scientists believe that trend is here to stay.

While many notorious dead zones, such as that in the Gulf of Mexico, have been attributed to agricultural run off, Kim Murphy of the L.A. Times and Scott Learn of the Oregonian report that increases in ocean temperatures, mostly linked to climate change, have been driving unique wind patterns and ocean currents that cause the suffocating conditions in the Pacific Ocean’s Northwest region.

Oxygen levels are typically lower in August and September off the coast of Oregon, triggered by a routine summertime mixing of cold, nutrient-rich deep water with warmer surface waters. But Oregon State University scientists say that records dating back to 1950 reveal that the last eight years have seen unprecedented oxygen depletion, and it’s likely to get worse.

Murphy and Learn’s news follows a recently released report by the National Science Foundation on ocean dead zones. The group’s research team said that summer die-offs are doubling every decade world-wide, largely due to human activities that alter oceanic and atmospheric conditions.

However, climbing ocean temperatures are not affecting every coast the same. A new University of B.C. study, published in the Global Change Biology, found that while climate change may cripple the fisheries of the West, it may actually increase catches in the East. Additionally, the study contends that those at higher latitudes are likely to see 30-70 percent jumps in what they reel in, whereas those in tropical waters can expect thinner nets in coming years.

— Natasha Walker

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