More than 4 million barrels of oil spilled into the Gulf of Mexico from the well drilled by the Deepwater Horizon oil rig, and though some of that oil has now disappeared, scientists are trying to figure out what the remaining oil is doing to marine life. A damage assessment for a place the size of the Gulf is a huge and complicated job, but out of sight does not mean out of mind.
"We want to say, 'Yes, everything's all good, the spill has been capped,' but in fact we don't really know what it means in terms of long-term impacts to birds, marine mammals, fish, shrimp, oysters," says Dana Wetzel, a marine chemist at Mote Marine Laboratory in Sarasota, Fla.
Wetzel and two colleagues from the lab are motoring out into the pale-blue waters of Sarasota Bay to test a device designed to find whatever oil is meandering through the Gulf. Wetzel calls it a "virtual shellfish." It's a membrane, sort of like a strip of plastic inside a metal housing the size of a cell phone. Water flows across the membrane, which collects contaminants like oil.
Once the device tells scientists how much oil or dispersant is in the water or sediment, scientists can calculate how the contaminants work their way up the food chain as big animals like spotted eagle rays eat smaller ones like clams.
It's a joint project with Baltimore's National Aquarium and Johns Hopkins University, and the plan is to offer the device to researchers in the rest of the Gulf. The team at Mote is doing the hands-on part of the research -- diving into Sarasota Bay to plant and then retrieve these devices with their contamination fingerprints.
"This is a much better approach in understanding the long-term impacts in an area versus simply collecting a sediment sample or a water sample," Wetzel says, because the Gulf is a huge body of water, and a sample here and a sample there is hit-or-miss. These devices are 30-day records of all the contamination that passes through an area.
Studying The Long-Term Effects
The "virtual shellfish" is just a tiny part of what marine scientists say is an almost impossible job. Finding where the oil and dispersant have been and are going is hard enough. Scientists then have to figure out what the contaminants may have done and will do.
"If a whale dies or a porpoise dies, then you've got a dead body that you can see," says Richard Pierce, an oceanographer at Mote. "But if larvae die, you have no idea what was there in the first place." When coral or giant tuna reproduce, they drop uncountable numbers of tiny larvae into the water. No one will know how many of them were or will be wiped out by the oil or dispersant.
But some preliminary tests of the dispersant used to break up the oil show that it can kill coral larvae. Marine life that survives exposure could suffer long-term, subtle effects that are very hard to measure.
"Once it impacts an organism and affects their genes and their endocrine system, then the damage is done," Pierce says.
The endocrine system controls things like growth and reproduction by producing and regulating hormones. The damage may not be evident until the next generation of tuna and coral fails to show up in its usual numbers.
Mote shark expert Robert Hueter says researchers are going to have to dig harder -- and spend more money -- to search for long-term damage.
"We're going to have to look much deeper," Hueter says. "We're going to be doing more looking inside the shark."
Who Foots The Bill?
Even if biologists find something amiss, they will then have to determine whether it was caused by the oil, by the dispersant or by something else. Kumar Mahadevan, the director at Mote, says the Gulf wasn't a terribly healthy place to start with.
"This Gulf has been insulted with a whole bunch of environmental issues over the years, from storm water runoff, from sewage runoff -- everything under the sun you can think of," he says.
Mahadevan says there is still very little money available for research. Right now, more than 200 scientific institutions are bidding for just $10 million that BP has offered the state of Florida.
Moreover, he says that with the Justice Department and BP preparing for litigation, scientists who take money from either side could be limited in what they can discuss or publish. And what scientists want to study -- like the oil's effects on plankton, for example -- may not be what lawyers are looking for.
"The legal system and the scientific system have different standards, and how all this is going to shake out is very interesting to watch," Mahadevan says.
It could be a very long watch -- scientists say it will take years to assess the damage, and years of lawsuits to determine who pays for it.