Gulf oil slick appears to vanish quickly

The New York Times reports: The oil slick in the Gulf of Mexico appears to be dissolving far more rapidly than anyone expected, a piece of good news that raises tricky new questions about how fast the government should scale back its response to the Deepwater Horizon disaster.

The immense patches of surface oil that covered thousands of square miles of the gulf after the April 20 oil rig explosion are largely gone, though there continue to be sightings of tar balls and emulsified oil here and there.

Reporters flying over the area Sunday spotted only a few patches of sheen and an occasional streak of thicker oil, and radar images taken since then suggest that these few remaining patches are quickly breaking down in the warm surface waters of the gulf.

The dissolution of the slick should reduce the risk of oil killing more animals or hitting shorelines. But it does not end the many problems and scientific uncertainties associated with the spill, and federal leaders emphasized this week that they had no intention of walking away from those problems any time soon.

The effect on sea life of the large amounts of oil that dissolved below the surface is still a mystery. Two preliminary government reports on that issue have found concentrations of toxic compounds in the deep sea to be low, but the reports left many questions, especially about an apparent decline in oxygen levels in the water.

And understanding the effects of the spill on the shorelines that were hit, including Louisiana’s coastal marshes, is expected to occupy scientists for years. Fishermen along the coast are deeply skeptical of any declarations of success, expressing concern about the long-term effects of the chemical dispersants used to combat the spill and of the submerged oil, particularly on shrimp and crab larvae that are the foundation of future fishing seasons.