Monday, August 07, 2006

Hypoxia is Strangling Narragansett Bay

Conditions are bad on Narragansett Bay. The Rhode Island Department of Environmental Management tested dissolved oxygen concentrations in the bottom waters at 53 locations recently and found that all of them were below 3 parts per million, which is too low for fish to survive. The Providence Journal:

All water below 12 feet was hypoxic, meaning that it did not have enough dissolved oxygen to support fish and crabs. …

The state's director of Environmental Management, W. Michael Sullivan, said that global warming was one of many factors contributing to the Bay's depleted oxygen levels. Sullivan said the annual average temperature of the Bay had increased by 3 degrees in 50 years, which, combined with nitrogen from sewage and a cut in tidal flow due to sedimentation, had stimulated the growth of algae and plankton. When that plant growth dies and decays, it consumes oxygen.

I suppose every environmental problem can be tied, one way or another, to global warming, but it’s a bit of a cop-out to say that it’s to blame for hypoxia, in Narragansett Bay or Long Island Sound or anywhere else. Enough nitrogen from sewage plants and runoff enter those estuaries (and Chesapeake Bay and the Gulf of Mexico) to push them over the edge every summer anyway. I can easily envision people saying that global warming requires such a long-term, planet-wide response that it’s useless to try to solve the bay’s problems.

I should also note that even when all of Narragansett Bay is involved, the area beset by hypoxia is still smaller that the hypoxic area of the Sound. The Sound is about 1,100 square miles and its hypoxic area often covers 300 square miles; the entire Narragansett Bay is 147 square miles. The average depth of the Sound is about 79 feet; the average depth of the bay is about 26 feet.

Last week there was also a big die-off of clams in the upper part of Narragansett Bay.

The Connecticut DEP sampled the Sound in late July-early August; the results should give us a good idea about whether the Sound will be in as bad shape as the Bay.


Post a Comment

<< Home

eXTReMe Tracker