Thursday, August 14, 2008

Dead Zones in Estuaries Around the World are Doubling in Size and Doubling Again

From the Washington Post...

... the number of oxygen-starved "dead zones" in coastal waters around the world has roughly doubled every decade since the 1960s, killing fish, crustaceans and massive amounts of marine life at the base of the food chain, according to a study released today.

... Diaz and co-author Rutger Rosenberg of the University of Gothenburg in Sweden counted more than 400 dead zones globally, ranging from massive ones in the Baltic Sea and the Gulf of Mexico to small ones that episodically appear in river estuaries. ...

Hypoxia has been seen for decades in such places as the Chesapeake Bay, Lake Erie, the Gulf of Mexico and Long Island Sound, but Diaz's survey has found new zones in the Florida Keys, Puget Sound and tidal creeks in the Carolinas.

"We're saying that hypoxia is now everywhere, it seems," said Diaz. "We can say that human activities really screwed up oxygen conditions in our coastal areas."



Blogger Sam said...

I think there's several things going on there. First, they're finding more and more "dead zones" every year as they improve satellite and water monitoring networks. Second, the number may be growing as to some new ones, a point I won't argue with. Third, some of dead zones appear to be expanding, or somehow getting worse over time.

There are even some hypoxic areas in the pristine islands of the Abacos, Bahamas. In the spring, a bunch of leaf matter ends up in the mangrove swamps on the lee side and makes a horrible rotting smell, rather like rotten eggs and diesel. That one is natural.

There's a huge one off Oregon in the Pacific, which seems to be from natural upwelling - although some suspect a link to Global Warming.

Not to push matters too much, but the western end of Long Island Sound is another "natural" dead zone. It just can't flush enough water in the heat of summer, and whatever is added to the water just kind of sits there. That's unlike the eastern end of the Sound near the Race, where fast currents flow in canyons miles wide and over 100 feet deep. -sam

p.s., glad to see ya post again!

10:00 PM  
Blogger Nan Patience said...

Man that's really scary.

12:55 PM  
Blogger Sam said...

Well it sounds like Tom got busy with his acting director job and went off to Block Island for a vacation, so your Texas correspondent wanted to fill in a little.

Folks up in the Northeast might know Block Island but it is a small 3 by 7 mile island about 12 miles off the coast of Rhode Island State. They've had some real good luck getting rid of those old septic systems and pipes using state and federal grants. They even hired a GIS programmer to pinpoint the repaired and "bad" septic systems (geographic information system, electronic mapping).

But the levels of nutrients and sometimes E. coli is still there, with no huge decrease as one would expect. This has some experts really scratching their heads, as the back-bays tended to get hypoxic in the summer, closing come shellfish beds. IN other words, if you cleaned up 70 to 80% of the problem, why wasn't there a 70-80% reduction in pollution?

I am not an aquatic biologist so I can only conjecture that there are other things happening. It will be interesting to see if Tom has any "on the scene" reports when he gets back.

Sam Wells
South Padre Island, TX

11:09 PM  
Blogger Monica said...

Hi Tom,
I just want you to know that I found your site recently, and have read your blog back as far as July 2007. I enjoy it so much that I just ordered your book.
Keep up the good work!

10:30 PM  

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