Mysterious dead zones in the Pacific

Scientists have documented unusual dead zones, or low-oxygen water conditions, off the coast of the US Pacific Northwest.

Jane Lubchenco: We’ve seen six in the past six years, and none before that. It’s surprising to see this in an area that is usually so rich with oxygen, and all of the conditions for life.

Jane Lubchenco is a marine biologist at Oregon State University. She said most dead zones are caused by nutrient pollution from fertilizer runoff.

Jane Lubchenco: But the dead zone that we’re seeing in Oregon and Washington is different, because it’s not connected to runoff of nutrients from the land, but instead is a result of changes in the upwelling of nutrients from the deep sea.

The excess nutrients take up all the available oxygen in the water, suffocating ocean life. Lubchenco described the scene on the ocean floor during the summer of 2006.

Jane Lubchenco: A virtual wasteland of dead Dungeness crabs, dead worms, dead stars, dead anemones, just littering the sea floor.

Lubchenco believes the dead zone is driven by changes in coastal winds, which may be related to climate change.

Jane Lubchenco: In the summertime this disaster strikes. In winter, the system returns to normal. And so things begin to recover, but just when they’re starting to recover, then next summer rolls around and another devastating impact – the system is getting hit every summer. So we have very real concerns that the long term consequences are not going to be good ones.

Our thanks today to NOAA, the National Oceanic and Atmospheric Administration.

February 18, 2009

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