Oil Spill in the Gulf

The magazine Science published (21 May 2010) an article summarizing what is currently known about the oil leak in the Gulf of Mexico(Gulf Oil Disaster:  Five Questions on the Spill by Richard A. Kerr, Eli Kintisch, Lauren Schenkman, Erik Stokstad. Science 2010 328:962-963).  Here, I have summarized some of the main points.

Underwater videos show that the oil leak may have been underestimated by as much as by an order of magnitude. Toxic components are volatilizing and remnant sticky tarballs are now reaching the coast.

Off-shore dispersants have yet to show their effectiveness as large subsurface plumes of oil are now detected. By dispersing the oil throughout the water column, the risk of toxic effects below the surface increases. It has been reported that the British oil company BP has already used about 715,000 gallons of the chemical Corexit, made by the Illinois-based company Nalco and banned in Britain.

The Environmental Protection Agency has ordered BP to switch chemical, but BP is fighting that order, the dispersant’s toxicity definitely jeopardizing local marine life. Both shellfish and fishing industries have been closed and determining when the catch will become safe again will be a challenge as easy screening tools to test contaminant levels do not exist and long-term impacts are difficult to evaluate.

Gulf’s marine mammals who will be breathing the toxic vapors and sea turtles feeding at the surface will be greatly affected by the on-going leak.   And so will the gulf seafloor composed of clams, mussels and tubeworms. Coastal marshes will be affected both by surface deposition of oil and by the seepage of oil in the soil affecting plant roots and soil processes for some time.

Both plants and the animals that depend on the marsh ecosystem such as mollusks, fish, shrimp and birds are already being affected. Louisiana’s wetlands have been continuously disturbed by human activities and are disappearing at the rate of 4400 ha per year (Erik Stockstad 2005 Science 310:1264-66). The oil could increase that number. Moreover if the leak continues, tropical storms could push more oil to shore and make things worse.

This environmental disaster in one of the most productive area of the Gulf that also affects local populations reeling from the impacts of devastating hurricanes shows once again how humans can transform a region. The proverb says “it’s an ill bird that fouls its nest” and one wonders if there is still time to find a cure to our society’s illness.