Assessing the social, economic effects of Deepwater Horizon spill

area of wetlands, the change in area is the most practical measurement of change in ecosystem services.  The service can be valued in monetary terms by estimating the cost of storm damage that would be incurred in the absence of the wetlands.

  • Fisheries.  Fishery closures decreased commercial production by 20 percent, which created an immediate economic hardship for fishermen.  The spill also triggered public concerns regarding the safety of Gulf seafood.  Productivity of the fish populations could be impacted by the spill’s toxic effects on reproduction and development, which may take years or decades to determine.  Although certain fisheries may experience persistent impacts, others have already shown signs of recovery. The economic value of fisheries as an ecosystem service can be calculated using data on market prices, harvest yields, and production costs.
  • Marine mammals.  Dolphins provide scientific, cultural, and recreational services in the Gulf of Mexico.  Beginning before the oil spill in February 2010 through December 2012, 817 bottlenose dolphin deaths were documented, compared with about 100 per year between 2002 and 2009.  Because some dead dolphins were likely not found and not reported, these figures underestimate actual mortality. Uncertainty regarding the abundance of dolphins and the range of environmental stressors that affect them, however, complicates the assessment of the true impact of the oil spill on their populations and the ecosystem services they provide.
  • Deep sea.  The deep sea is the largest yet least well-understood region of the Gulf, making it difficult to assess the full impact of the oil spill on ecosystem services.  Among the services derived from the deep sea are pollution attenuation by hydrocarbon-degrading microbes, and nutrient recycling, which supports much of the marine biodiversity at all depths in the Gulf of Mexico.

    • In addition, the committee evaluated a suite of technologies used in the spill response. Techniques applied offshore, including burning, skimming, and chemical dispersants, reduced the volume of oil by as much as 40 percent before it reached shore, while those applied near or onshore were comparatively less effective and more expensive. The unprecedented scale at which these techniques were applied, however, leaves the long-term impacts on ecosystem services to be determined, the report says.

    The NRC says that lack of data on the ecological conditions of the Gulf before the spill and an incomplete understanding of complex ecosystem interactions make establishing the full scope of damage difficult. Capturing the entire range of impacts will also require more data on human and economic factors, as well as the development of models that can describe the complex dynamics of ecosystem interactions and better inform decision makers. The report emphasizes that many services may have enormous value despite being difficult to measure, and that such services should be given adequate consideration in evaluating restoration options.

    The study was sponsored by the National Oceanic and Atmospheric Administration.

    — Read more in An Ecosystem Services Approach to Assessing the Impacts of the Deepwater Horizon Oil Spill in the Gulf of Mexico (National Academies Press, 2013)