Bruce Mate didn’t wait long. Within days of the April 20 Deepwater Horizon oil well blowout in the Gulf of Mexico, he was on the phone with officials from the U.S. Minerals Management Service. From 2001-2004, the agency had funded him to study the Gulf’s endangered sperm whales. Now, the director of Oregon State University’s Marine Mammal Institute had an idea: By tracking the sperm whales again, he could provide useful data to federal agencies and the well’s owner, British Petroleum, on the impact of spilled oil on the marine ecosystem.
Working through an emergency-response process known as Natural Resource Damage Assessment, Mate negotiated a contract with BP in which OSU would own the data. BP and the National Marine Fisheries Service would have access to determine damages for future settlements. By the end of May, Mate and institute staff members Craig Hayslip and Ladd Irvine were on the research ship Gordon Gunter (owned by the National Oceanic and Atmospheric Administration), which had been quickly re-tasked from the North Atlantic to support five spill-related science missions.
Mate wasn’t the only OSU researcher to respond as the world watched crude spew into what the Census of Marine Life has ranked as one of the globe’s most diverse marine systems. Professor Kim Anderson in the university’s Superfund Research Program marshaled a crew to track chemical contamination along the shore. At four sites from Pensacola, Florida, to Grand Isle, Louisiana, they deployed devices that essentially sniff the air and water for an oil component known as polycyclic aromatic hydrocarbons, or PAHs. And in September, a team led by Stephen Brandt, director of Oregon Sea Grant, conducted an acoustic survey of fish in an area northwest of the spill site.
Researchers are still analyzing data, and while images of oil-soaked pelicans, turtles and other animals are seared in the public mind, it will be a while before the broader biological significance of the spill is known.
Following the Whales
In late December, Mate was following six of the dozen whales that he had tagged in June near the damaged well. One of them was among 58 that he had tagged in the previous project. Data from that effort, he says, form a baseline, which can be used to compare whale behavior after the 2010 spill.
“I don’t expect to see sperm whales directly affected by oil,” Mate says, “but if oil or dispersants have dramatically affected the squid they eat, the secondary effect will likely influence the movements of the whales. They sort of vote with their flukes.”
A pioneer in satellite-based whale tracking, Mate says the whales that had initially traveled northeast from the well (in the direction of oil visible at the surface) had changed course and were in the western Gulf, some close to the Mexican coast. As his lab continues to monitor whale movements, researchers will use the data to analyze the size of the whales’ home ranges. They’ll also consider whether significant differences between 2010 and previous years suggest that whales avoided heavily oiled waters.
Pollutants on the Increase
While Mate was making his plans, Kim Anderson in OSU’s Department of Environmental and Molecular Toxicology was assembling sampling devices and personnel to track PAHs, a group of more than 100 compounds that the U.S. Environmental Protection Agency classifies as “highly potent carcinogens.”
Supported by OSU’s Environmental Health Sciences Center, Anderson and her team, including Ph.D. student Sarah Allan (see “After the Spill”), started deploying their equipment on May 9, before oil began washing ashore. As the oil slicks and tarballs hit beaches and wetlands through the summer, PAH concentrations rose to about 40 times over baseline levels, according to preliminary data.
“There are a range of health effects associated with PAHs,” says Anderson. “They are toxic by several different modes of action. We’re now using a technique that looks at the fraction of PAHs that are bioavailable — that have the potential to move into the food chain.”
Over the next two years, with support from a National Institute of Environmental Health Sciences grant, the lab will continue sampling in each location for more than 1,200 different compounds: PAHs, pesticides, PCBs and other industrial chemicals, many of which are known to disrupt hormone signaling.
For Stephen Brandt, oil is only one of the threats to fish habitat in the Gulf of Mexico. At least as significant is the persistent presence of a low-oxygen region west of the Mississippi River outlet, a.k.a., the “dead zone.” As part of a multi-institution project that began in 2003, Brandt has collected data on water quality and fish behavior in order to assess the dead zone’s impact on fisheries.
A pioneer in the use of acoustics to study fish, Brandt has led five sampling expeditions to the Gulf. His September cruise, with OSU faculty research assistants Sarah Kolesar and Cynthia Sellinger, was the first after a major oil spill, but it was not the first to reflect the presence of crude. Natural oil seeps pour an estimated 41 million gallons into the Gulf every year, he points out.
During eight days of sampling, Brandt and his team saw no oil, but they did see evidence for the first time of “a very intense double-layered dead zone” with low-oxygen patches near the bottom as well as higher in the water column. The location and severity of low-oxygen zones can shift from day to day. It will take additional data analysis to identify the factors behind the 2010 pattern.
Brandt knows it will take time for the Gulf’s rich marine life to respond. In 1979, the region received a large gush of crude from Mexico’s Ixtoc 1 well, which fouled beaches and estuaries from Texas to the Yucatán Peninsula. After that event, it took three to five years for fisheries to come back, he says. Some species, he adds, may never recover.
Article courtesy of Terra Magazine
Photo by Stephen Brandt