What was that odd flotsam that appeared after the Gulf oil spill ?
Right after the Deepwater Horizon oil rig exploded April 20, 2010, marine scientist Monty Graham from the Dauphin Island Sea Lab in Alabama began exploring Gulf of Mexico waters to document the unfolding consequences of the unprecedented oil spill.
“Following the blowout, we were going out on the water every other day or so,” he said, to collect water samples and make observations.
On May 5, about 32 miles south of the Alabama coast, they observed something strange.
“The water was flat, glassy calm,” Graham said. “We started seeing these weird objects bobbing in the water—odd white things with an oily halo in the water around them.”
But there was no trace of the wide oil slick on the ocean surface that was spreading out in all directions from the sunken Deepwater Horizon site. Some 50 relatively small pieces of the mysterious white flotsam, interspersed with sargassum weed, extended in an east-west line for 6 miles.
Graham and colleagues collected samples, the largest about the size of a softball.
The material was hard but porous and uniformly embedded with black spheres less than a half-inch in diameter.
Two days later, the researchers collected similar samples about 25 miles south of Dauphin Island.
Nobody knew what the material was. Some speculated it came from Deepwater Horizon; others hypothesized that it could be coral or another substance made by marine plants or animals.
Graham sent a few pieces of the material to Chris Reddy, a marine chemist at Woods Hole Oceanographic Institution (WHOI), where Reddy and colleagues determined that the material was a manmade, not natural, substance.
The WHOI scientists then analyzed the oil on the debris using comprehensive two-dimensional gas chromatography, a technique that can identify the thousands of individual chemical compounds that comprise different oils from different reservoirs.
The chemical “fingerprint” of the oil on the debris matched that of oil from Deepwater Horizon. Still, the researchers did not know what the material was or where it came from.