Sunday, August 06, 2006

"The dead zone is coming"


More bad news...

"A "dead zone" of low-oxygen water that has been killing fish and crabs along the Washington and Oregon coast could be coming to B.C., scientists say.

This is the fifth year in a row that dead marine life has been washing up on beaches owing to a dead zone, which may be more evidence of global warming."

...Last week, members of Washington state's Quinault Indian Nation discovered large numbers of dead rockfish, flatfish and greenling, said Liam Antrim, a resource-protection specialist with the Olympic Coast National Marine Sanctuary.

"Crab have been reported, whole crab -- not just the shells -- off the beaches in the southern half of the Washington coast"...

More of the story (Aug.7)...

Scientists studying the 70-mile-long zone of oxygen-depleted water, along the Continental Shelf between Florence (Oregon) and Lincoln City, conclude that it is being caused by explosive blooms of tiny plants known as phytoplankton, which die and sink to the bottom, then are eaten by bacteria which use up the oxygen in the water.

The recurring phytoplankton blooms are triggered by northerly wind, which generates a process known as upwelling in which nutrient-rich water is brought to the surface from lower depths....

Scientists first noticed a dead zone off Newport in 2002. That one was traced back to a rare influx of cold water rich in nutrients and low in oxygen that had migrated from the Arctic, said Jack Barth, professor of oceanography at Oregon State and with Lubchenco a principal investigator for the Partnership for Interdisciplinary Studies of Coastal Oceans.


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It sounds like these might be at least partly a result of melting glaciers in the Arctic region.

1 comment:

meret said...

Update: Thursday, August 10, 2006

'Dead zone' startles scientists

Graveyard - offshore areas of the Pacific Ocean completely empty of marine life

Ocean scientists took their first look Tuesday into the oxygen-starved "dead zone" spreading off the Oregon Coast and were shocked by what they saw: a lifeless wasteland of thousands of dead crabs, starfish and no live fish at all.

"It was a real eye-opener for all of us," said Hal Weeks, a marine ecologist with the Oregon Department of Fish and Wildlife. "I don't think anybody expected this sort of thing."

Dead Dungeness crabs off Cape Perpetua, just south of Yachats, "were like jellybeans in a jar. You just can't count them, there were so many."

Oxygen levels in places along the central Oregon Coast have sunk to the lowest levels ever recorded on the West Coast of the United States, said Francis Chan, a marine ecologist at Oregon State University and the Partnership for Interdisciplinary Studies of Coastal Oceans, an alliance of research institutions.

Scientists suspect swings in the Earth's climate tied to global warming may be shifting wind conditions to bring about such grim results.

Seawater turns deadly for marine life when concentrations of the dissolved oxygen they breathe fall below about 1.4 milliliters per liter. On Monday, Chan measured a concentration of .05, or almost 30 times below the lethal level, about 90 feet below the surface.

It is very close to a complete absence of oxygen, a situation rarely known in the world's oceans, said Jane Lubchenco, a professor of marine biology at Oregon State. New bacteria that take over when oxygen disappears are known to release poisonous hydrogen sulfide gas...