In early May, after oil in the Gulf of Mexico began lapping at the Louisiana coast, James Bellingham of the Monterey Bay Aquarium Research Institute, in California, sent a flurry of e-mails to colleagues, asking if they could deploy "gliders" to track the spread of the slick. By the fifth week of the disaster, the autonomous, torpedo-shaped submersibles started showing up, sent by Rutgers University, iRobot, and others. The robotic technology, just a decade old, was ready to take on a new challenge.
The gliders move by repeatedly changing their buoyancies, collecting data from the ocean while undulating through it [see "Yellow Submarine," IEEE Spectrum, March 2010]. Little by little, they're building a picture of what's happening to the oil—where the currents are carrying it, and how the chemical dispersants applied at the spill site are transforming it. And they're doing it at a much higher resolution than is possible with traditional ocean-observing tools.
"The uses for these vehicles always amaze me," says Clayton Jones, an engineer at Teledyne Webb Research, in Falmouth, Mass., which made 6 of the 10 gliders shipped to the Gulf.
The gliders are packed with sensors that measure currents, temperature, salinity, and water density. They also carry organic-matter-detecting fluorometers, typically used for measuring decaying debris. In the Gulf, oceanographers are testing how useful these sensors really are for finding oil.
And because gliders use very little power to fill and deflate the oil bladders that propel them, they can endure in the sea for up to nine months. "It's like giving a teenager a set of car keys," Jones says. "You never know when he'll come back."
But the gliders almost always check in. Every three hours or so, they pop to the surface and beam their data to satellites and get directions from pilots. The National Oceanic and Atmospheric Administration is using the transmitted glider data to make more accurate predictions about where the oil will go.