Scientists at Columbia University used a new technique to analyze underwater video of the leaking well riser to determine it leaked some 56,000 to 68,000 barrels daily -- maybe more -- until the first effective cap was installed July 15, a university release says.
Their estimate of the amount of oil that escaped into the open ocean is about 4.4 million barrels -- close to the most recent consensus of government advisers, whose methods have not been detailed publicly.
"We wanted to do an independent estimate because people had the sense that the numbers out there were not necessarily accurate," Timothy Crone, a marine geophysicist at the university's Lamont-Doherty Earth Observatory, said.
The scientists studied high-resolution video of the leaking well from underwater cameras to track the motion of turbulent billows and flows in the water, breaking down the movement pixel by pixel.
Crone developed the technique in 2006 to study natural hydrothermal vents, volcanically driven cracks and holes in the seafloor that shoot out buoyant, superheated jets of mineral-laden water.
"This is a great example of how basic research that doesn't seem to have any immediate value suddenly gains huge immediacy for society," Crone said.