Anoxic Water To Shore in Belle Pass

July 2004

To:,,,,,,,, Schleifstein_M,,,,,,,,,,,,,, Dunne_Mike, St.Pe_Kerry,,,,, <,,,,,

From: Nancy Rabalais <>
Subject: Re: notice from surfers @ Fourchon

lAll, I did not have an email for Pat Breaux, so maybe someone can send this forward.

On the 17th there was probably a pretty strong SE flow onshore as the front approached.  This would blow the surface waters inshore, including any algal blooms, which still continue to be quite intense.  The shift of wind from the NW to offshore would have set up upwelling favorable conditions that would push surface waters offshore and pull bottom waters onshore.  This would mean cooler, oxygen deficient, even anoxic waters.  The result is often a jublilee or a fish kill.  Given the black water and H2S smell, I suspect that anoxic water from offshore moved onshore after the frontal passage.  The H2S would have also blackened any silver.  We encountered this type of water several times in dives in July offshore.  The hypoxia is fairly intense right now, and is likely the cause of the Sunday Jul 18th conditions.

Nancy Rabalais

At 03:21 PM 7/19/2004, you wrote:

Pat Broeaux from DEQ in Lockport called to tell us that surfers noticed that the water was a "beautiful turquoise green color" in Belle Pass ( at the mouth of Bayou Lafourche) on Saturday the 17th, then on Sunday the 18th they reported the waters in the same area as being much cooler and black, smelling like sewage and turned their sterling silver ring black ( sulfides?).  Wind direction was between 230-330 degrees( coming from the SE? Is that right?) on both days . He just wanted to alert us with an FYI . I told him we were going out on Tuesday night and he said he was going out there tomorrow and would call if he found something interesting.