USF Marine Science Continues Focus on Spill

A year after the spill, scientists seek answers to lingering questions on environmental impact, better monitoring systems.

Researchers aboard the University of South Florida's R/V Weatherbird II conducting experiments in a previously unexplored region of the Deepwater Horizon oil spill.


By Vickie Chachere

USF News


ST. PETERSBURG, Fla. (April 19, 2011) – The Deepwater Horizon was 300 miles off the coast of West Central Florida, drilling in an area of the Gulf of Mexico so deep much of it had been unexplored at the time of the explosion.

For scientists, that part of the Gulf was one of the great mysteries of their work. A spawning area and habitat for majestic creatures like blue fin tuna and whale sharks, its depths also harbor a community of tiny creatures rarely - if ever - seen by man. The well ruptured in what many scientists believe to be one of the worst possible spots for the species that call the Gulf home.

As millions of barrels of oil gushed into the Gulf over three tense months, University of South Florida scientists were on the front lines of assessing the spill’s impact on the Gulf and Florida’s beaches. Now, as the first anniversary of the nation’s largest environmental disaster is marked, scientists have only yet to begun to understand the complicated impact on the sensitive Gulf ecosystem.

From toxic oil found in the sediments which might affect the microscopic creatures at the base of the vast Gulf food web to microscopic oil now sifted into the sugary-sand beaches of Florida’s Panhandle, the spill has not only altered the environment but continues to command the attention of dozens of researchers. The methodical process of understanding how the spill has ricocheted through the environment remains underway, a full understanding of the spill impact is years – if not a decade – away, the scientists say.

The USF researchers do agree on one definite finding: the oil may not be largely visible anymore, but it is certainly not gone.

 “When you look at the ultimate impact of the oil spill you have to look at the impact on the entire ecosystem,” said Jackie Dixon, dean of USF’s College of Marine Science. “That means doing what we’re doing: looking at the sediments on the sea floor where oil has accumulated that is going to work its way up through the food chain. We know the little things have been hurt and it takes time to work its way up.”

If any researcher at USF can say anything definitive about the Gulf oil spill, it is USF Geologist Ping Wang, who studied the impact of the oil on the Florida Panhandle’s famed white beaches. The day the oil made landfall in Florida in a devastating assault on Pensacola Beach, Wang jumped in his car and headed north to scientifically document the startling event.

In the months that followed, he and the researchers at USF’s Coastal Geography Lab kept a keen eye on the sands even after BP crews had “cleaned” them up. Digging just a few inches down as a child playing on the beach would, the researchers found layers of buried oil. Beaches that had been mechanically cleaned of large tar mats were found to be littered with millions of tiny tar balls rather than truly being cleaned.

But in February, Wang and his researchers announced some good news: the beaches they’d been studying had undergone a methodical sifting cleanup that had removed the tar balls. What’s left behind, however, is microscopic contamination that under UV lights still glows as evidence of the oil that remains in the environment. Government officials have said the remaining oil is in low concentrations that do not pose a hazard to human health and that any more aggressive cleanup could cause more environmental damage.

But of lingering concern is the possibility that tar mats just off the coast could be disturbed by storms and re-deposited on the beach. Also of concern is the impact of microscopic oil on the swash zone – the area where waves deposit sea plants and is a crucial feeding zone for small creatures, such a ghost crabs, which keep the beach environment alive.

Susan Bell, chair of USF’s Department of Integrative Biology, is investigating that aspect of the spill in a separate project funded by the National Science Foundation.

“The amenity beaches are in really good shape, but oil gets cleaned up every day,” said Rip Kirby, a researcher in Wang’s lab who is permanently stationed on the northern Gulf beaches. “It’s going to be that way for the next three to five years.”

Geological Oceanographer Ben Flower is one of several USF researchers studying the effects of the microscopic oil found by his College of Marine Science colleagues in the DeSoto Canyon in August. There’s good reason to focus on this particularly deep geological feature just south of the Florida Panhandle: it’s where flow models developed by Physical Oceanographer Robert Weisberg clearly predicted underwater plumes of oil and it’s an important source of nutrient-rich water that feeds Florida’s spawning grounds.

The DeSoto Canyon is a formidable place to work, dropping sharply off the continental shelf into waters so deep researchers simply refer to it as “the abyss.” Since work on assessing the impact of the BP spill on sediments and the deep-dwelling communities there, however, the way microscopic oil has settled in the canyon has led to a less poetic description from Flower: a bathtub ring.

Flower, working with USF Chemical Oceanographer David Hollander - who fingerprinted both the undersea plumes identified by USF researchers in May and oil contamination of the sediments found in August back to the BP well – have found an accumulation of microscopic oil in the DeSoto Canyon at both 400 meters and 1,000 meters, about the same depth of the deep-sea oil plumes.

USF researchers have repeatedly returned to the area in a number of ventures aboard the R/V Weatherbird II, and in a rigorous process of taking cores of canyon sediments seen persistent pattern of microscopic oil settling into the canyon, where normally small worms and organism would burrow into the sediments and serve as a food source for larger creatures.

“The impact of this is you are suffocating the organisms,” Hollander said. “It’s like a blizzard.”

Biological Oceanographer Ernst Peebles was aboard the mission of the R/V Weatherbird II that made international headlines for locating two massive plumes drifting northeast of the ruptured well at a time when then BP CEO Tony Hayward was insisting all the oil had remained on the surface. The plumes were created by both the atomization of the oil bursting out of the well and the use of chemical oil dispersants at depth, which had never been done in an oil spill before.

Now Peebles’ lab is looking in perhaps the most unexpected place for evidence of oil exposure: fish ears.

The ear bone of a fish, it turns out, is an excellent chemical recorder of the environment in which a fish lives, Peebles explains. As fish swim through the water, their ear bones are constantly growing and absorbing a wide variety of chemical elements in the water. Like rings of a tree, a scientist can analyze rings in a fish ear bone and tell the quality of the environment a fish was living in at different points in its life.

In his lab, a freezer holds hundreds of fish of various species captured both in clean and oiled water. Graduate students slice the ear bone in a cross-section of the growth layers. The bone is then shot with a laser at specific points in the growth pattern; the vaporized bone is then immediately analyzed for chemical composition and elements left by oil show up in the readings.

Peebles and his students have methodically worked their way through more than 350 fish captured in clean water to establish a baseline to compare fish from the spill zone. Only now is their painstaking study  beginning to look at fish who spent their last days and months swimming in a mix of water, oil and dispersants.

“It’s not common for fish to be exposed to oil in the ocean, so if they’ve been in it we should see the evidence,” Peebles said.

“We’re looking to see if the growth rates of these fish changed after exposure to oil. Slow growth in fish usually translates into reduced survival rates.”

Weisberg, USF’s Distinguished Professor of Physical Oceanography, was among the first to respond to the spill with his sophisticated, multi-layer Gulf tracking systems that monitor currents and winds. Chuanmin Hu, an Associate Professor of Optical Oceanography, watched the spill grow from the skies using images from NASA satellites that showed its growing, silvery sheen on the water. Together, their labs worked exhaustive hours, seven-days a week to keep tabs on which way the oil was moving.

Now a year later, USF’s researcher who tracked the spill published a compelling look at the flawed technologies that complicated an effective response in EOS Transactions, a leading scientific publication.

The current system – a conglomeration of various modeling systems which calculate currents and winds that move the Gulf waters and uses satellite imagery that can identify surface oil slicks – is imperfect and fraught with assumptions which can undermine its accuracy. The limits of the modeling system call for several future improvements, said the article authored by Yonggang Liu, Weisberg, Hu and Lianyuan Zheng.

Better integrated systems are needed, but that takes major investment from the federal government to accomplish. With resources strained and uncertainty over what proceeds from BP fines will flow to science, the prospects for developing a more reliable system seem far off.

Ocean monitoring has become a major focus of another large research project led by Frank Muller-Karger, a biological oceanographer with an expertise in remote sensing technology. Working with Mitch Roffer, a Melbourne oceanographer who had a business helping sport fishermen find fish only to see his skills drafted into tracking oil, the research group is working on fusing satellite and other  data to identify and track surface oil and contaminated water.  

Muller-Karger said his project also has assembled comprehensive satellite datasets on Gulf temperature and phytoplankton concentration fields in the Gulf of Mexico for the past 15 years which will be used to understand how the Deepwater Horizon spill affected regional temperatures and plankton concentrations.

Using images from airborne cameras over the northern Gulf coasts, the researchers are advancing
the engineering of optical oil sensing technology into sonobuoys dropped from airplanes to measure profiles of hydrocarbons from the water’s surface to several hundred meters depth. When combined with satellite images, the new technology will help assess oil distribution below the Gulf surface in 3D, Muller-Karger said.

Of all the places he could have been when the Deepwater Horizon exploded, it is eerie for Steve Murawski to remember where he was that night: Sendai, Japan, the epicenter of last month’s devastating earthquake and tsunami.

Murawski, who joined USF as the holder of the St. Petersburg Downtown Partnership - Peter R. Betzer Endowed Chair at the College of Marine Science in January, was then the director of scientific programs and chief science advisor for the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service. He was in Sendai to give a talk on the impact of climate change on the health of the world’s fisheries, but soon was thrust into a central role in the scientific response to the spill.

Murawski remains a leading voice in support of rigorous scientific examination of the spill and in encouraging academic, local, state and federal entities to work collaboratively in understanding how the repercussions of the disaster will play out for both the Gulf ecosystem and the people who depend on it for their health and livelihood.

But making sure scientists are prepared to respond takes investment – and the months that have passed since the BP spill have seen few new resources devoted to advancing scientific capabilities, even as the oil industry begins eyeing the Gulf for further deep-sea drilling.

“No one was prepared for the immensity of scale of what occurred – it could almost make your head explode,” Murawski said.

“What I wonder about now is if we are in danger of losing our capacity (to respond). Unless there is sustained support to keep our capabilities together, will we be prepared next time? And there will be a next time.

“If it happened tomorrow, are we prepared to get out and understand what is going on? I think not. This needs to be the cost of doing business as far as these industries go. It’s been a wakeup call, and not just for BP.”

Vickie Chachere can be reached at 813-974-6251.