Ocean “dead zones” are leading to marine life death, say scientists

WNN Earth Watch

NOAA chart of dead zones in Gulf of Mexico U.S.
Dead zone layers in the coastal region of the U.S. Gulf of Mexico is expected to be the largest yet every recorded this year, says NOAA – National Atmospheric and Oceanographic Administration. These regions will see the killing off of marine and fish life due to unhealthy levels of oxygen in the water. Image: NOAA

(WNN) Washington, D.C., UNITED STATES, AMERICAS: Our rivers, lakes and sea life may be in serious danger, outlines a new forecast by NOAA – National Oceanographic and Atmospheric Administration as the largest ‘dead-zone’ in the Gulf of Mexico to date is expected to be part of this year’s ocean environment events.

Causing fish and botanical life to die in multitudes in the water, dead zones are zones where dangerous conditions knock out life forms like oysters, shrimp and other shell fish.

“…this year’s Gulf of Mexico hypoxic ‘dead’ zone will be between 7,286 and 8,561 square miles which could place it among the ten largest recorded. That would range from an area the size of Connecticut, Rhode Island and the District of Columbia combined on the low end to the New Jersey on the upper end. The high estimate would exceed the largest ever reported 8,481 square miles in 2002,” says NOAA.

Bringing data together by the University of Michigan, Louisiana State University, and the Louisiana Universities Marine Consortium news studies show that impacts to our waterways through excessive nutrient pollution, a majority which is coming from the agriculture industry, is causing the largest ever reported dead zone, which is exceeding the 8,481 square miles of dead zone reported in 2002.

“Scientists are expecting a very large ‘dead zone’ in the Gulf of Mexico and a smaller than average hypoxic level in the Chesapeake Bay this year, based on several NOAA-supported forecast models,” added NOAA.

Dead zones in waterways are areas where marine life starts to die off or has trouble growing or living. Lack of oxygen in the water is the culprit as hypoxic (low oxygen) and anoxi (no oxygen) levels in water causes fish colonies to die in mass as well as small aquatic marine animals and plants to die.

“Less oxygen dissolved in the water is often referred to as a “dead zone” because most marine life either dies, or, if they are mobile such as fish, leave the area. Habitats that would normally be teeming with life become, essentially, biological deserts,” says NOAA.

Climate change and weather pattern changes may also be contributing to the waterway conditions as dead zones in specific regions reach larger than ever reported levels.

According to NOAA the dead zone estimate in the Gulf is based on weather assessments pointing to no significant tropical storms in the two weeks “preceding or during the official measurement survey cruise scheduled from July 25-August 3 2013.”

“If a storm does occur the [dead zone] size estimate could drop to a low of 5344 square miles, slightly smaller than the size of Connecticut, NOAA outlines.

“Monitoring the health and vitality of our nation’s oceans, waterways, and watersheds is critical as we work to preserve and protect coastal ecosystems,” said Kathryn D. Sullivan, Ph.D., acting under secretary of commerce for oceans and atmosphere and acting NOAA administrator.  “These ecological forecasts are good examples of the critical environmental intelligence products and tools that help shape a healthier coast, one that is so inextricably linked to the vitality of our communities and our livelihoods.”

The main culprit in the change that could affect fish and plant species are part of biologic factors affecting our waterways. Hypoxia is the main culprit in the water, say global ecology experts like Sullivan.

“The forecasts call for a mid-summer hypoxic zone of 1.46 cubic miles, a mid-summer anoxic zone of 0.26 to 0.38 cubic miles, and a summer average hypoxia of  1.108 cubic miles, all at the low end of previously recorded zones.  Last year the final mid-summer hypoxic zone was 1.45 cubic miles,” continues NOAA.

Water pollutants affecting the health of the earth’s water and the healthy balance of oxygen in waterways include toxic substances like pesticides, raw sewage and industrial waste that is all part of human activity.

The dead zone in the Gulf of Mexico affects nationally important commercial and recreational fisheries, and threatens the region’s economy. The Chesapeake dead zones, which have been highly variable in recent years, threaten a multi-year effort to restore the Bay’s water quality and enhance its production of crabs, oysters, and other important fisheries.

“Coastal hypoxia is proliferating around the world,” said Donald Boesch, Ph.D., president of the University of Maryland Center for Environmental Science. “It is important that we have excellent abilities to predict and control the largest dead zones in the United States. The whole world is watching.”

The National Centers for Coastal Ocean Science is part of the coastal science office for NOAA’s National Ocean Service. NOAA and other agencies are carefully charting dead zones now as a way to determine the health of global waterways.  Part of NOAA’s mission is to “understand and predict changes in the Earth’s environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources.”


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