2013-10-03 / Front Page

Deepwater Horizon findings

Port Aransas scientists explain research on giant oil spill
Dan Parker

Working in a lab at the University of Texas Marine Science Institute are, from left, professors Brad Gemmell, Ed Buskey and Rodrigo Almeda, all studying the effects of oil and dispersants on plankton. They were wearing protective glasses because they were using lasers as part of their research. 
Courtesy photo Working in a lab at the University of Texas Marine Science Institute are, from left, professors Brad Gemmell, Ed Buskey and Rodrigo Almeda, all studying the effects of oil and dispersants on plankton. They were wearing protective glasses because they were using lasers as part of their research. Courtesy photo Scientists in Port Aransas have found that dispersants used to break up the Deepwater Horizon oil spill were more harmful to certain tiny Gulf of Mexico creatures than the oil itself.

Researcher Ed Buskey will present that and other findings when he attends the Symposium on Deep Sea Oil Spills at the Ocean University of China in Qingdao, China, Oct. 28-30.

Buskey is a plankton ecologist with the University of Texas Marine Science Institute in Port Aransas. The institute won a grant of nearly $7 million – the largest in the facility’s then 70-year history – in fall 2011 to fund a project that will investigate how waves, currents, tiny organisms and other Gulf of Mexico features can disperse oil spills. Buskey was the one who applied for the grant.

The Gulf of Mexico Research Initiative (known as GRI) awarded the grant. The project has been led by Buskey and includes institute researchers Deana Erdner and Zhanfei Liu. UTMSI researcher Tracy Villareal also is involved in GRI-funded projects. He is one of the scientists doing research in a project led by the University of Mississippi.

Buskey pulled together scientists from around the nation to take part in the research. The researchers are from institutions including Johns Hopkins University, the University of Wisconsin, University of Pennsylvania and the University of Minnesota.

The GRI was formed to distribute $500 million in independent scientific research related to the Deepwater Horizon oil spill that took place after an explosion that killed 11 workers.

The money was provided by BP, the oil and gas company involved with Deepwater Horizon.

The GRI is managed by the Gulf of Mexico Alliance – a partnership between the states of Texas, Alabama, Florida, Louisiana and Mississippi to increase regional collaboration to enhance the ecological and economic health of the Gulf.

The GRI Research Board announced in 2011 that eight research groups, including the one based at UTMSI, would be funded with $112.5 million for the next three years.

The teams took on the task of investigating the fate of petroleum in the environment, the impacts of the spill and the development of new tools and technology for responding to future spills and improving mitigation and restoration.

The Deepwater Horizon explosion produced one of the largest oil spills in history, spewing millions of gallons of oil into the Gulf of Mexico for 87 days before it was capped. More dispersant than ever – 1.7 million gallons – was applied to the spill, Buskey said.

A judge at a trial underway in New Orleans is trying to determine, once and for all, how much oil flowed into the Gulf and what the companies involved in the spill should have to pay in environmental penalties.

The UTMSI scientists haven’t finished their research yet, but they have produced some findings.

“One of the main things we found is, with the addition of all the dispersant, the oil breaks up into really small droplets, about a micron in size,” Buskey said. For comparison’s sake, a grain of salt is about 500 microns in size.

The droplets “are colonized by all these bacteria, and that helps them degrade, and they also get consumed by small organisms,” he said. “We find that things like zooplankton are actually eating (the slightly larger) oil droplets.”

Zooplankton are the many trillions of almost microscopic creatures that float throughout the world’s seas, constituting a fundamental building block in the food chain.

The oil was slightly toxic to zooplankton, sometimes killing the organisms, but not usually, Buskey said.

The researchers found that the dispersants were two to three times more toxic to zooplankton than the oil itself, Buskey said. Oil also became more toxic to the organisms when dispersants were added to it, he said.

Buskey said zooplankton specimens built up oil toxins in their tissues. Specimens were found to have toxin levels hundreds of times higher than the toxin levels in the water around them, he said.

Those toxins are passed up the food chain, though many sea creatures have livers that will filter out toxins, Buskey said. Finfish are the best at filtering it out. Crabs and shrimp are not as good at it. Shellfish are the most likely to retain toxins in their tissues.

It wasn’t necessarily a bad idea to use dispersants after the Deepwater Horizon spill, Buskey said. Dispersants likely kept masses of oil from getting into marshes and sea grass beds along the coast – ecologically sensitive areas that are nurseries for many species of fish and shrimp, he said.

“There are always pluses and minuses to everything,” Buskey said. “It’s a trade-off.”

Dispersants should be used “sparingly,” he said.

There was “some depression” in zooplankton populations after the Deepwater Horizon spill and dispersant use, but they’re now back to normal, Buskey said.

Zooplankton creatures live short lives (up to about two months) and reproduce quickly, he said.

Dr. Robert Dickey is another UTMSI official who has been heavily involved with research related to the Deepwater Horizon spill. Dickey is director at the institute. His previous post was director of the U.S. Food and Drug Administration (FDA) Gulf Coast Seafood Laboratory and Division of Seafood Science and Technology on Dauphin Island, Ala. He held that position at the time the spill occurred. He was principal author of the FDA’s response plan and protocol to assess seafood safety after the disaster.

Gulf seafood generally is safe to eat, and there are several reasons for that, Dickey said.

For one thing, he said, only about one or two percent of the oil’s chemical make-up was toxic or a carcinogen.

After giving sea life a chance to metabolize the oil and dispersants, federal authorities extensively sampled consumable sea life throughout the Gulf of Mexico. Toxin levels in the specimens overall turned out to be below the levels for public health concern, Dickey said.

How could such a big oil spill happen without a wholesale poisoning of sea life throughout the Gulf?

One answer: “Oil has always been in our environment,” Dickey said. Some 40 to 50 million gallons of oil naturally seep from the bottom of the Gulf each year, he said.

“Nature has evolved to accommodate that,” he said.

But it took 86 days to cap the hole that was spewing oil at a point 35,000 feet deep, and all that oil did hurt larval crab and shrimp, producing a drop on those populations in the northern Gulf, Dickey said. Finfish were hurt, but bounced back, he said.

Dickey pointed out that the spill did harm public health by producing fumes that hurt responders dealing with the spill on shore and out on the water.

Another reason Gulf life wasn’t wiped out: While the spill was big, the Gulf of Mexico is thousands of times bigger.

“There’s a huge dilution effect immediately happening,” Dickey said.

Still another factor: The oil was lighter than the product lost in spills such as the Exxon Valdez incident that took place in Alaska in 1989. As a result, the evaporation rate was higher.

Still, fisheries were closed for months around the northern Gulf, and some remain closed. Due to the lack of fishing going on for a while, some fisheries ended up with bigger populations than before the spill, Buskey said.

A scientist who formerly worked at UTMSI, Paul Montagna, also is involved in researching the effects of the spill. Montagna now holds the Endowed Chair for Ecosystems and Modeling at the Harte Research Institute for Gulf of Mexico Studies at Texas A&M University-Corpus Christi.

An article on the National Oceanic and Atmospheric Administration’s website quoted Montagna, who lives in Port Aransas, on his research.

“Normally, when we investigate offshore drilling sites, we find pollution within 300 to 600 yards from the site,” Montagna said in the story. “This time it was nearly two miles from the wellhead, with identifiable impacts more than 10 miles away. The effect on the bottom of the vast underwater plume is something, which until now, no one was able to map. This study shows the devastating effect the spill had on the sea floor itself, and demonstrates the damage to important natural resources.”

The story said the deepsea soft-sediment ecosystem in the immediate area of the spill will likely take decades to recover.

Montagna said shellfish, small crustaceans and mollusks were the bottom-dwelling species most affected.

The full impacts of the Deepwater Horizon spill still are being uncovered, Dickey said.

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