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Largest dead zone ever expected in Gulf

29th June 2011   ·   0 Comments

By Zoe Sullivan
The Louisiana Weekly

Scientists from Louisiana University Marine Consortium, LUMCON, are predicting that the “Dead Zone” — an area with low or no oxygen — in the Gulf of Mexico this year will be the largest ever. In scientific terms, this is called a “hypoxic” area. Predic­tions are that the area will stretch from 8,500 square miles to 9,400 square miles. An annual summer phenomenon, the hypoxia affects marine life and the communities that depend on that life. Dr. Nancy Rabalais, the executive director of LUMCON, told The Louisiana Weekly: “There’s an area the size of New Jersey or Mas­sachusetts where you can’t fish in the summer.”

Hypoxia occurs because a spurt in algal blooms, given impetus by minerals pouring into the Gulf from the Mississippi River, dies and falls to the ocean floor where it decays, using up oxygen that would sustain fish and other life. The biggest feeders of the algae are nitrogen and phosphorous. The former is a fertilizer commonly used with corn, which has seen a boom because of the growing use of ethanol. The latter is a by-product of cow manure. Both minerals run off from fields in states like Iowa, Illinois and Indiana where tributaries feed into the Mississippi River.

LUMCON held an adult education workshop in early June on the “dead zone” at its Cocodrie facility. Roughly 20 people attended a lecture and tour to learn what is happening just off Louisiana’s coast and how that ties into the water carried by the Mississippi. The water in the Bay is fresher than usual because of the Missis­sippi River flooding.

Matt Rota, the Science and Water Policy Director for the Gulf Restoration Network, told The Louisiana Weekly that the National Academy of Sciences had issued a report calling the Mississippi River an “orphan” because no government entity was taking responsibility for its health. What happens to the river however, he said, ends up in the Gulf where coastal residents deal with the consequences.

The Gulf Restoration Network suggests a two-fold strategy for dealing with the problem. Rota suggested that the regulations encoded in the Clean Water Act, which was used in the 1970s and 80s to get mercury out of the water system and to clean up rivers that were catching fire., The same tools could be applied to the Mississippi River. “…A couple of years ago, we petitioned the EPA [Environ­mental Protection Agen­cy] to do two things” Rota said. “One is to set numeric standards for nitrogen and phosphorous.” Currently, the only enforcement of water quality standards for these kinds of minerals is voluntary, according to Rota. As a result, the Gulf Restoration Network is advocating for setting a “Total Maximum Daily Load,” or TMDL, which would cap the amounts that could be dumped into the river. Rota calls this a “pollution budget,” which would be divided amongst the states responsible for the harmful run-offs.

A recent report in National Geographic magazine explained how hypoxia – or no oxygen – in the Gulf of Mexico has an impact on fish reproduction. Researchers in Texas found that the Atlantic Croaker, a common Gulf fish, would not develop as many females as it would under ordinary oxygen circumstances. The Croak­er’s offspring are male by default, some becoming female as they develop ovaries.

Professor Prosanta Chakrabarty is an icthyologist and the Fish Curator at Louisiana State Univ­ersity. He warns that this kind of impact on fish sexual development could have serious consequences for the fishing industry. “If there’s a skewed sex ratio, there’s going to be a smaller number of individuals the following year. And if there’s a crash due to increased fishing pressure and a crash due to strange development of females becoming males, that’s hitting it from two sides, and that’s a big problem for any fish species.” The Croaker is a very common and well-studied species. As a result, Chakrabarty says, it may be possible to infer similar issues with other types of fish.

Advocates aren’t the only ones who feel something needs to be done. Since the dead zone affects fishing in the Gulf, people from that industry agree that there needs to be more regulation. Cliff Hall runs the New Orleans Fish House, a seafood processor and distributor that sells roughly 75,000 pounds of fish weekly. “I would be very much in favor of regulating what goes into the river because no matter what point it goes into the river, it ends up here. So, y’know, how many ever miles it goes up North, all of that does end up in our estuary system, and that is vital to Louisiana. It’s what sets us apart from other states.”

Gulf Coast residents are concerned about the welfare of their environment and want steps taken upriver to lessen the impact of fertilizers. But the leading authority on the dead zone, Rabalais, says that the issue is creating problems upstream, too. “The issue of nutrients just is not just a Gulf of Mexico issue. There are a lot of contaminated water wells in the Midwest, contaminated drinking water. Some cities like Des Moines and Columbus, Ohio have to put on tertiary treatment to reduce the nitrate in the drinking water, so that’s a problem. There are noxious and harmful algal blooms up in the water shed because of nutrients, and many of them are toxic.”

This article originally published in the June 27, 2011 print edition of The Louisiana Weekly newspaper.

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