Soon after the Deepwater Horizon spill occurred in the Gulf of Mexico, a group of public and private organizations — including the University of Delaware and the Delaware Biotechnology Institute (DBI) — came together to assist in the cleanup.
The institutions joined the Deepwater Horizon Response and were tasked with employing the best techniques to clean up the spill while trying to save the wildlife affected.
UD’s contribution to the effort, led by oceanographer Matt Oliver, was to help the team understand where the oil might travel next and establish the baseline characteristics of the ecosystem before the oil moved in.
Oliver and his UD colleagues helped with the processing of real-time data, as well as the deployment of an autonomous underwater vehicle called a Slocum Electric Glider. The glider is a remotely operated robot that swims a saw-tooth pattern and scans the ocean interior for traces of oil. Together with satellite data, the glider allowed scientists to track ocean currents, and therefore, where the oil might be traveling.
“This information helped us determine where we needed to focus cleanup efforts,” said Oliver, who is an assistant professor of oceanography in the College of Earth, Ocean, and Environment.
The work was made possible through funding by the National Oceanic and Atmospheric Administration (NOAA), NASA, and through the Delaware Sea Grant program at UD.
UD’s autonomous underwater vehicle took part in two missions, one in June that lasted about 26 days, and one in late July and early August, which lasted about that long.
Halfway through its second mission, the glider hadn’t seen any evidence of oil in the locations off west Florida where it was launched. It had, however, mapped out the location of phytoplankton in the area. Knowing the density of the microscopic plants that form the basis of the food web is important, Oliver said, because if they get wiped out by oil it would have effects throughout the food web.
“This glider effort gave us the best scientific picture of the West Florida Shelf that we’ve ever seen,” he said.
The data Oliver and his team collected was analyzed through a cluster of computers housed at DBI. These computers use the institute’s powerful cyber-infrastructure to calculate data based on input from UD’s team of researchers. These data streams were visualized in real-time at the Global Visualization Lab on the Hugh R. Sharp Campus in Lewes, Del.
The G-Vis Lab, as it is known, uses Google Earth to view many real-time data streams all at once on a large collection of flat-screen TVs.
“The interactive display of the G-Vis brought all this data into one spot so we could make intelligent decisions about where the glider should go next for sampling,” Oliver said.
“This effort to facilitate real-time monitoring of events in the Gulf was an example of how the DBI infrastructure can be effectively directed to support faculty research, interact with other institutions and help reduce the environmental impact of the leak,” said Kelvin Lee, DBI director.
UD is one of several university partners involved with the Integrated Ocean Observing System (IOOS), which coor-dinated the creation of the Deepwater Horizon Response.
UD’s Global Visualization (G-Vis) Lab uses Google Earth to view real-time data streams on everything from ocean temperature and currents to the movement of ships in Delaware Bay — all at once.
The data come from a wide variety of sources, including satellites, autonomous underwater vehicles, and floating buoys, and are pulled into Google Earth via KML files, special file types that let you see geographic data.
When viewed on the lab’s flat-screen TVs and navigated with a 3-D mouse, the Google Earth globe and any data illustrated on it are seen with such high resolution and great detail that viewing the image feels more like a high-flying helicopter ride.
Not only is it incredibly impressive to see in action, the technology represents a new way for oceanographers to see a wide variety of real-time data all in one spot and in a standardized format that anyone with Google Earth and the right KML files can use.
The technology provides a completely new sense of the ocean, said the lab’s creator, Matt Oliver, assistant professor of oceanography.
“Oftentimes you’re out on a boat and you wonder what it is that you’re missing. When you’re out there you feel so small,” Oliver said. “This technology really allows you to see the large scales of the ocean unfold in
front of you.”
Oliver is part of a larger cooperative effort between multiple universities and institutions working on the visualization project, including the Mid-Atlantic Regional Coastal Ocean Observing System, Rutgers University and NASA’s Jet Propulsion Lab. The endeavor is funded by the Office of Naval Research, NASA, the National Science Foundation, the National Oceanic and Atmospheric Administration, and Delaware Sea Grant, among others.
Besides its current use in oil spill cleanup efforts, scientists foresee far-reaching applications for the technology, from studying the health of coral reefs, to the salinity of Delaware Bay, to how climate change has affected habitats on the West Antarctic Peninsula.
Graduate students Matt Grossi and Erick Geiger are working with Oliver on files that will allow researchers to see new types of geographic data, even view real-time tracks of electronically tagged penguins.
Like most of us, Dom Di Toro cringes when he sees photos of oil-slicked pelicans in the Gulf of Mexico and tar balls in the shore’s sugary sand. But he’s just as worried by what he can’t see — the toxic effects of oil on the water and sediment environments.
“It’s easy to see the direct, or physical, effects,” Di Toro says, “while the chemical effects tend to be invisible. However, what’s going on below the surface can be just as devastating as the oil slicks that
we can see on the surface.”
Di Toro, the Edward C. Davis Professor in UD’s Department of Civil and Environmental Engineering, is an expert in water quality and sediment quality criteria models for organic chemicals, metals and mixtures.
The Environmental Protection Agency (EPA) relies on researchers like him to help develop methodologies for predicting toxicity so that criteria for water and sediment quality can be developed. Such criteria are used to assess risk and guide cleanup efforts.
“At first glance, it would seem that it is difficult to determine just how toxic oil is,” Di Toro says. “Petroleum is made up of tens of thousands of hydrocarbons, and it’s not feasible to perform toxicity tests on that many chemicals.” The issue is further com-plicated by the fact that the chemicals involved are combined into mixtures, suggesting the potential for incremental toxicity.
However, all oil compounds are narcotic chemicals — that is, they all exert their toxicity by the same mechanism, Di Toro says. Their similar mode of action means that their toxicities can be added using a method called toxic units, and it also means that 30 or 40 compounds — rather than 10,000 — can be measured to provide a fairly accurate picture of what is happening.
“Just how clean is clean?” Di Toro asks. “At what level of concentration do you have to remediate the water or sediment that has come in contact with it?” This is the central problem in assessing damages caused by the spill, and the problem that water and sediment quality criteria are designed to answer.
Sediment, an area of particular interest to Di Toro, comprises an ecosystem in itself, with the oil’s toxins affecting not only the organisms dwelling in the sediment, but also the creatures who feed on them.
Di Toro and his research group have developed a procedure for deriving equilibrium partitioning sediment benchmarks, an approach that enables the toxicity of nonionic chemicals in sediments to be predicted mathematically using only chemical measurements. The procedure is now an EPA methodology that is being applied to help establish baseline information about conditions in the Gulf and to assess changes in those conditions as the spill progresses.
Di Toro and his colleagues have also carried out studies to determine the effect of weathering on the toxicity of oil components. Common wisdom would suggest that because lighter compounds are less toxic than heavier components of oil and evaporate more quickly, toxicity would increase over time. But it turns out that the heavier compounds are so much less soluble in water that the overall toxicity of water that is in contact with oil actually decreases over time.
“Quantity is everything in this business,” Di Toro says. “Zero concentration is a meaningless idea in an industrial society. The fact is
that contaminants are in our environment. What matters is the amount and their
bio-availability — whether there is enough to harm us or the wildlife or the plant life. In
toxicology, the dose makes the poison.”