Considered the largest accidental marine oil spill in history, April 2010’s BP’s Deepwater Horizon incident in the Gulf of Mexico challenged scientists to think about the way in which oil and other pollutants move in the ocean.
Scientists in the University of Delaware’s College of Earth, Ocean, and Environment (CEOE), in partnership with other researchers, conducted the largest deployment of ocean drifting instruments to date and found that small-scale ocean currents play a major role in the spread of pollutants at the ocean surface.
Their findings will help better predict the path of pollutants from future oil spills or nuclear disasters. They provide new information about significant dispersion patterns currently un-accounted for in ocean models.
“The scientific community is very skilled at observing large-scale ocean features, using satellites and other instruments, and forecasting them with ocean models. In this study, we emphasized scales of 100 meters to 10 kilometers. Ocean flow at these scales, which are very small given the vastness of the ocean surface, are poorly understood. That is what we were able to quantify,” said Bruce Lipphardt, research associate professor in CEOE’s School of Marine Science and Policy.
For hundreds of years, dropping things into the ocean and watching their movements has been a way for explorers and scientists alike to learn about ocean currents. The use of drifting items in the ocean to monitor currents is not new to the scientific community. Modern “drifters,” however, use on-board GPS sensors to report their positions in real-time via satellite.
“In the 1970s projects might have used as many as 70 drifters deployed over the course of a year, taking readings two to four times a day,” according to Denny Kirwan, CEOE professor emeritus and one of the pioneers of research using ocean drifters. “For this project we had 310 drifters deployed in two weeks, reporting positions every five minutes. We were also analyzing many other measurements made by our ship and satellites. This was an enormous jump in data, making this a truly ‘big data’ project.”
“This experiment is helping to answers questions that arise in all major oil spills, such as ‘where will the oil go?’ and ‘how fast will it get there?’ which are important when allocating limited response resources and determining the overall socio-economic impact of the spill,” said Tamay Özgökmen, UM Rosenstiel School professor and Consortium for Advanced Research on Transport of Hydrocarbon in the Environment director.
The study, titled “Submesoscale Dispersion in the Vicinity of the Deepwater Horizon Spill,” was published in the Aug. 18 issue of the journal Proceedings of the National Academy of Sciences (PNAS).
(Source: University of Delaware)