jueves, 6 de mayo de 2010

Oil Spills and Wildlife

The recent Deepwater Horizon oil spill off the shore of Lousiana brings back memories of the devastation left behind after the Exxon Valdez oil spill of 1989. There are serious concerns as the the effects the current spill will have on gulf wildlife, everything ranging from the death of plancton and algae, the toxification of shellfish, and even the suffocation of whales and dolphins. This concern stems from the unfortunate but enormous knowledge we have about these effects thanks to the history of our oil industry. Studies from the twenty years after the Valdez spill have revealed some of the longterm and irreversible aftermath on coastal habitats. A study done by the Centre for Wildlife Ecology, Simon Fraser University, British Columbia has shown that even 20 years later, organisms are ingesting small amounts of oil, with effects reverberating through the food chain. The main focus of the study was the harlequin duck. "In addition to the higher likelihood of exposure due to their habitat, harlequin ducks have a number of characteristics that makes them particularly sensitive to oil pollution. Their diet consists of invertebrates that live in this area and have a limited ability to metabolize residual oil. Also, harlequin ducks have a life history strategy based on high survival rates, as well as a small body size when compared to other sea ducks." A different study done by Temple University has determined that the rate of natural biodegradation of the oil has slowed considerably due to low levels of oxygen and nutrients, as the oil has sunk into the beaches. The bacteria that have evolved to metabolize oil require conditions of high oxygen concentration to quickly digest the oil, which the pristine environment of Alaska can not provide. Biodegradation rates that were at once 70% are now down to 4%. The oil, which was supposed to have been completely biodegraded by now, still lingers. When reflecting upon the status of the Valdez shoreline, the future of the gulf coast looks dim, as this spill keeps spewing oil from the well by the day.

For an article on the current spill in the gulf:

For the study on Harlequin Duck:

For the study on the rate of biodegradation:


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