More Bad News from Coastal Louisiana

People who understand how crude oil affects living organic material must have seen the writing on the wall. And, yes, we’re talking about the April 2010 BP-Deepwater Horizon oil spill. A group of scientists from the University of Florida and two Dutch universities recently reported what they found after studying direct and indirect effects of the oil spill on Louisiana’s coastal marshes. Please note that the study combined biological and geomorphological field investigations with control sites (reference marshes) and coastal morphology modeling techniques so the researchers could understand the complex dynamics of key coastal processes. They were concerned about the health of Louisiana coastal habitats since salt marshes provide critical ecosystem services to plants and sea life.

The researchers found the oil-affected marshes had hydrocarbon concentrations more than 100 times that of unaffected reference marshes, a near total loss of above ground vegetation extending up to 30 feet from the water’s edge, and oil-driven plant death on the seaward margins more than doubled pre-existing rates of shoreline erosion. In simple English that means that the marshes on which most commercial and sport fishing depends on for vital nursery services are disappearing at twice the previously measured rate. Although the study found clear evidence of plant recovery at affected sites, overall the oil spill caused an accelerated decline of salt marshes that were already being degraded at an alarming rate as a result of stress introduced by human activities.

The authors conclude by stating: “It (the study) warns of the enhanced vulnerability of already degraded marshes to heavy oil coverage and provides a clear example of how multiple human-induced stressors can interact to hasten ecosystem decline.”

The trouble is most of us have already put the BP-Deepwater Horizon disaster in the “out of sight, out of mind” category and have moved on, literally and figuratively. We don’t want to think about the consequences or relate them to human actions other than those that can be categorized as technological accidents. We just want to get on with our lives as though nothing happened.

Source: Silliman, B. R., van de Koppel, J., McCoy, M. W., Diller, J., Kasozi, G. N., Earl, K., Adams, P. N., and Zimmerman, A. R. (2012). Degradation and resilience in Louisiana salt marshes after the BP-Deepwater Horizon oil spill. Proceedings of the National Academy of Sciences, Published online before print June 25, 2012, doi: 10.1073/pnas.1204922109; Retrieved on June 26, 2012, from http://www.pnas.org/content/early/2012/06/20/1204922109.full.pdf+html