Ecologists' worst fears are realized

May 19, 2010 15:00 GMT  ·  By
Envisat ASAR data showing the oil slick in the Gulf of Mexico making its way into the Loop Current (red)
   Envisat ASAR data showing the oil slick in the Gulf of Mexico making its way into the Loop Current (red)

According to the most recent data collected by satellites of the European Space Agency (ESA), the oil that has been spilling in the Gulf of Mexico for about a month now has entered the Loop Current. Ecologists have been warning about this danger for weeks, but authorities were unable to plug the leaks, or at least protect coastlines, let alone take care of the underwater plumes spreading all over the place. Data from the Envisat spacecraft suggests that the powerful conveyor belt that moves eastwards in the Gulf, towards the coasts of Florida, has now been contaminated with crude.

“With these images from space, we have visible proof that at least oil from the surface of the water has reached the current,” Dr. Bertrand Chapron, who is an expert at the French Research Institute for Exploitation of the Sea (Ifremer), says. The expert has been monitoring the data flowing from the Envisat Advanced Synthetic Aperture Radar (ASAR) instrument for days. Together with CLS expert Dr. Fabrice Collard, he has been keeping an eye on the close proximity between the crude on the surface of the waters and the edges of the Loop Current. Just yesterday, US scientists using the R/V Pelican discovered that underwater plumes of crude were also spreading away from the original spill site.

As visible in the image, the ASAR data is conclusive – a huge tendril of crude flow southwards, and then towards the southeast from the place where the British Petroleum-operated drilling rig sunk. The Loop Current is denoted with a red arrow. “We performed advanced processing methods on the images to display surface features like variations in roughness and velocity, which provides insight into the spatial structure of the spill and its transport by surface currents,” Dr. Collard reveals. This newest image of the oil slick has been taken yesterday, May 18. Data collected on May 12 and May 15 shows how the slick gradually moved closer to the Current. Contact between the two was inevitable, scientists say. Already-sensitive coral reefs in the Florida Keys are now under direct threat, ecologists add.

“Now that oil has entered the Loop Current, it is likely to reach Florida within six days. Since Envisat ASAR, ERS-2 and other SAR satellites are systematically planned to acquire data over the area, we will monitor the situation continuously,” Chapron adds. The scientists also issued a warning: due to the fact that the Loop is very strong, and also very deep, a mixing process is bound to occur, where the crude will be carried underwater, and mixed with the liquid. “This might remove the oil film on the surface and prevent us from tracking it with satellites, but the pollution is likely to affect the coral reef marine ecosystem,” Dr. Collard explains.

Researchers also do not exclude the possibility of the oil causing an immense disaster alongside the US eastern seaboard, affecting cities such as Washington and New York. The Loop Current spills directly into the Gulf Stream, the single most powerful current in the North Atlantic. This water current is the one that keeps North America and the West coast of Europe warm, and its contamination would have far-reaching and long-lasting implications for marine wildlife over decades to come.

The Deepwater Horizon semi-submersible drilling rig, which operated only tens of miles South of the coasts of Louisiana, suffered a large explosion on April 20. 11 crew members are assumed dead, and all rescue efforts aimed at finding them have long since been called off. On April 22, the rig sunk into the waters of the Gulf, in spite of the fact that emergency response ships were on-site, evacuating workers, and pouring water on the platform. With the collapse of the Horizon, the pipes that carried the oil from a depth of 5,000 feet (1,500 meters) broke.