Salt Marsh Responses to Oil Contamination Following the Deepwater Horizon Oil Spill

Salt Marsh Responses to Oil Contamination Following the Deepwater Horizon Oil Spill
Author:
Publisher:
Total Pages: 135
Release: 2018
Genre: Electronic books
ISBN:

The Deepwater Horizon oil spill, which occurred from April to July of 2010, was the largest spill in U.S. history. Oil washed onto hundreds of kilometers of intertidal marsh shoreline resulting in widespread plant mortality and short-term reductions in ecosystem function. Past incidences of oiling have shown that marsh recovery trajectories can vary greatly over space and time. Accordingly, the long-term negative effects of an oil spill of this magnitude on marsh ecosystems remains largely unknown. This dissertation investigates the effects of oil contamination from the Deepwater Horizon oil spill on community dominant plant species distributions and land loss rates and, simultaneously, demonstrates the value of employing advanced remote sensing and GIS techniques to address landscape-scale ecological disturbances. To examine the response of marsh plant communities to heavy oiling, dominant species in heavily oiled salt marshes, an image classification system was developed to map dominant species. This classification approach utilizes canonical discriminant analysis (CDA), along with a library of field-referenced image endmembers collected from a time series of Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) images (2010-2012). Land loss rates were calculated using the normalized difference vegetation index (NDVI)applied to a time series (2006-2016) of high resolution (0.30-0.64 m) orthorectified image datasets. Finally, a simple, fetch-limited wind-wave model was integrated into the analysis of shoreline oiling and land loss to examine the interacting effects of wave characteristics and oiling on bay-wide land loss rates.This dissertation’s findings suggest that the most important impact of oiling along marsh boundaries is the acceleration of shoreline retreat and land loss. Further, the results imply that marsh responses to oil contamination are highly variable, and wave action is a significant factor in determining marsh recovery trajectories. Without high wave energy, marsh plant communities show signs of recovery within 3 years of oil contamination. Conversely, oiled shorelines that are exposed to high wave energy can accelerate land loss exponentially. Finally, the results demonstrate the value of advanced remote sensing techniques in examining landscape-scale ecosystem changes that are impractical to assess using traditional, field-based quantitative methods.

An Ecosystem Services Approach to Assessing the Impacts of the Deepwater Horizon Oil Spill in the Gulf of Mexico

An Ecosystem Services Approach to Assessing the Impacts of the Deepwater Horizon Oil Spill in the Gulf of Mexico
Author: National Research Council
Publisher: National Academies Press
Total Pages: 247
Release: 2014-01-20
Genre: Nature
ISBN: 0309288452

As the Gulf of Mexico recovers from the Deepwater Horizon oil spill, natural resource managers face the challenge of understanding the impacts of the spill and setting priorities for restoration work. The full value of losses resulting from the spill cannot be captured, however, without consideration of changes in ecosystem services-the benefits delivered to society through natural processes. An Ecosystem Services Approach to Assessing the Impacts of the Deepwater Horizon Oil Spill in the Gulf of Mexico discusses the benefits and challenges associated with using an ecosystem services approach to damage assessment, describing potential impacts of response technologies, exploring the role of resilience, and offering suggestions for areas of future research. This report illustrates how this approach might be applied to coastal wetlands, fisheries, marine mammals, and the deep sea-each of which provide key ecosystem services in the Gulf-and identifies substantial differences among these case studies. The report also discusses the suite of technologies used in the spill response, including burning, skimming, and chemical dispersants, and their possible long-term impacts on ecosystem services.