Wednesday, August 12, 2009

Low Dissolved Oxygen Alert for Narragansett Bay

Over the past couple of weeks, we have observed severe hypoxia (low dissolved oxygen) conditions throughout much of the Upper and Mid-Narragansett Bay including the Providence River, and Greenwich Bay, and extending down the West Passage to Quonset Point.

While we often see low oxygen conditions at this time of year as water temperatures peak, this year it appears to be particularly bad, possibly due in part to the record-breaking rainfall in July. So far, Save The Bay has not received any reports of fish kills, but we are on high alert.

There aren't as many juvenile menhaden, or "peanut bunker", as we've seen in past years, and these are often the first to die off when the conditions deteriorate, so that could be one reason why we're not seeing more dead fish. The following is excerpted from an e-mail broadcast by Chris Deacutis, Chief Scientist for the Narragansett Bay Estuary Program:

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Just a note for folks who may be working out on the upper half of Narragansett Bay over the next 1.5 weeks- it looks like a severe hypoxic (to near anoxic) event is ongoing in Greenwich Bay and Upper Bay north to the Seekonk River , with low DO all the way down-Bay to Quonset area. We are entering a neap tide cycle next week , so tidal energies will stay weak until ~ 8/17. The volume of low DO water column seems substantial at Conimicut Pt. We saw oxygen in the 0.2-0.5 mg/L range in western Greenwich Bay on Tues below ~ 3.5 m, and continuous buoys are indicating things are worsening over wider areas.

I'd appreciate an email if anyone spots any unusual situations physically or biologically.

Chris Deacutisdeacutis@gso.uri.edu Christopher Deacutis, PhD
Chief Scientist
Narragansett Bay Estuary Program
Tel (401) 874-6217
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Save The Bay would also like to know if you see anything unusual. E-mail me at jtorgan@savebay.org or call 401 272-3540 x 116 to report a fish kill or other water-quality related events. Thanks, JT