COLLEGE STATION Researchers at Texas A&M University have confirmed for the first time that a dead zone has existed off the Texas coast for at least the past 23 years and will likely remain there, causing potential harmful effects to marine life in the area.
Steve DiMarco, associate professor in Texas A&Ms College of Geosciences who has studied dead zones in the Gulf of Mexico for more than 15 years, believes the dead zone area off the Texas coast extends from the Texas-Louisiana border area to Brownsville. A dead zone occurs when there is hypoxia, or oxygen-depleted water.
Such low levels of oxygen are believed to be caused by pollution from farm fertilizers as they empty into rivers and eventually the Gulf, or by soil erosion or discharge from sewage treatment plants.
Not all of the area from the Texas-Louisiana coast to Brownsville is a dead zone area, but very much of it is, DiMarco explains. The Texas dead zone appears to be more patchy and not as continuous as the Louisiana dead zone to the east, but much of the region there has very low oxygen levels, some extremely low.
DiMarco recently presented his findings to the 2008 Ocean Sciences Meeting in Orlando, Fla.
DiMarco examined water samples provided by Texas Parks and Wildlife, NOAA (National Oceanic and Atmospheric Administration) and other groups from the area taken since 1985 and found that, with few exceptions, dead zone areas have occurred almost every year since that time.
Key areas sampled included Sabine Pass, Matagorda Ship Channel, Galveston-Boliver Pass, Aransas Pass and Brazos-Santiago (Brownsville) Pass.
Water samples contained low oxygen levels, and in some years, alarmingly low, DiMarco said. When a dead zone occurs, marine life can be severely threatened, especially commercial fishing areas.
The low oxygen levels since 1985 are frequent and persistent, he noted.
It proves that a dead zone occurrence
|Contact: Keith Randall|
Texas A&M University