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Detection of salt marsh vegetation stress and recovery after the Deepwater Horizon Oil Spill in Barataria Bay, Gulf of Mexico using AVIRIS data.

Khanna S, Santos MJ, Ustin SL, Koltunov A, Kokaly RF, Roberts DA - PLoS ONE (2013)

Bottom Line: Four indexes of plant stress and three indexes of canopy water content all consistently showed that stress was highest in pixels next to the shoreline and decreased with increasing distance from the shoreline.Index values along the oiled shoreline were significantly lower than those along the oil-free shoreline.We demonstrate that post-oiling trends in terms of plant health and mortality could be detected and monitored, including recovery of these saltmarsh meadows one year after the oil spill.

View Article: PubMed Central - PubMed

Affiliation: Center for Spatial Technology and Remote Sensing (CSTARS), Department of Land, Air and Water Resources, University of California Davis, Davis, California, United States of America.

ABSTRACT
The British Petroleum Deepwater Horizon Oil Spill in the Gulf of Mexico was the biggest oil spill in US history. To assess the impact of the oil spill on the saltmarsh plant community, we examined Advanced Visible Infrared Imaging Spectrometer (AVIRIS) data flown over Barataria Bay, Louisiana in September 2010 and August 2011. Oil contamination was mapped using oil absorption features in pixel spectra and used to examine impact of oil along the oiled shorelines. Results showed that vegetation stress was restricted to the tidal zone extending 14 m inland from the shoreline in September 2010. Four indexes of plant stress and three indexes of canopy water content all consistently showed that stress was highest in pixels next to the shoreline and decreased with increasing distance from the shoreline. Index values along the oiled shoreline were significantly lower than those along the oil-free shoreline. Regression of index values with respect to distance from oil showed that in 2011, index values were no longer correlated with proximity to oil suggesting that the marsh was on its way to recovery. Change detection between the two dates showed that areas denuded of vegetation after the oil impact experienced varying degrees of re-vegetation in the following year. This recovery was poorest in the first three pixels adjacent to the shoreline. This study illustrates the usefulness of high spatial resolution airborne imaging spectroscopy to map actual locations where oil from the spill reached the shore and then to assess its impacts on the plant community. We demonstrate that post-oiling trends in terms of plant health and mortality could be detected and monitored, including recovery of these saltmarsh meadows one year after the oil spill.

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Photosynthetic vegetation cover from shore to inland along oiled and oil-free shoreline.Percentage of photosynthetic vegetation pixels in oiled vs. oil-free shoreline zones in September 2010 (“1” being the first pixel from the shore and “12” being the twelfth). Total number of pixels for each zone for oiled and oil-free shoreline is shown above the bars.
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pone-0078989-g005: Photosynthetic vegetation cover from shore to inland along oiled and oil-free shoreline.Percentage of photosynthetic vegetation pixels in oiled vs. oil-free shoreline zones in September 2010 (“1” being the first pixel from the shore and “12” being the twelfth). Total number of pixels for each zone for oiled and oil-free shoreline is shown above the bars.

Mentions: The impact extended four pixels inland (0–14 m from shore). The percentage of pixels classified as photosynthetic vegetation was lower in the first four zones (<60%) in oiled shorelines relative to the corresponding zones in oil-free shorelines (>90%), consistent with observations on the index value trajectories (Figure 5). By the fifth pixel from the shore, the difference in percent of photosynthetic vegetation along oiled vs. oil-free shoreline was much narrower (83.8% vs. 93.2% or 9.4% difference). Beyond the first five pixels, the percentage of photosynthetic vegetation pixels along oiled and oil-free shorelines was similar and above 90%. Pixels in the second and third zone away from the shoreline were the most affected by oil (had the lowest percentage of photosynthetic vegetation pixels) followed by pixels adjacent to the shoreline.


Detection of salt marsh vegetation stress and recovery after the Deepwater Horizon Oil Spill in Barataria Bay, Gulf of Mexico using AVIRIS data.

Khanna S, Santos MJ, Ustin SL, Koltunov A, Kokaly RF, Roberts DA - PLoS ONE (2013)

Photosynthetic vegetation cover from shore to inland along oiled and oil-free shoreline.Percentage of photosynthetic vegetation pixels in oiled vs. oil-free shoreline zones in September 2010 (“1” being the first pixel from the shore and “12” being the twelfth). Total number of pixels for each zone for oiled and oil-free shoreline is shown above the bars.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3818498&req=5

pone-0078989-g005: Photosynthetic vegetation cover from shore to inland along oiled and oil-free shoreline.Percentage of photosynthetic vegetation pixels in oiled vs. oil-free shoreline zones in September 2010 (“1” being the first pixel from the shore and “12” being the twelfth). Total number of pixels for each zone for oiled and oil-free shoreline is shown above the bars.
Mentions: The impact extended four pixels inland (0–14 m from shore). The percentage of pixels classified as photosynthetic vegetation was lower in the first four zones (<60%) in oiled shorelines relative to the corresponding zones in oil-free shorelines (>90%), consistent with observations on the index value trajectories (Figure 5). By the fifth pixel from the shore, the difference in percent of photosynthetic vegetation along oiled vs. oil-free shoreline was much narrower (83.8% vs. 93.2% or 9.4% difference). Beyond the first five pixels, the percentage of photosynthetic vegetation pixels along oiled and oil-free shorelines was similar and above 90%. Pixels in the second and third zone away from the shoreline were the most affected by oil (had the lowest percentage of photosynthetic vegetation pixels) followed by pixels adjacent to the shoreline.

Bottom Line: Four indexes of plant stress and three indexes of canopy water content all consistently showed that stress was highest in pixels next to the shoreline and decreased with increasing distance from the shoreline.Index values along the oiled shoreline were significantly lower than those along the oil-free shoreline.We demonstrate that post-oiling trends in terms of plant health and mortality could be detected and monitored, including recovery of these saltmarsh meadows one year after the oil spill.

View Article: PubMed Central - PubMed

Affiliation: Center for Spatial Technology and Remote Sensing (CSTARS), Department of Land, Air and Water Resources, University of California Davis, Davis, California, United States of America.

ABSTRACT
The British Petroleum Deepwater Horizon Oil Spill in the Gulf of Mexico was the biggest oil spill in US history. To assess the impact of the oil spill on the saltmarsh plant community, we examined Advanced Visible Infrared Imaging Spectrometer (AVIRIS) data flown over Barataria Bay, Louisiana in September 2010 and August 2011. Oil contamination was mapped using oil absorption features in pixel spectra and used to examine impact of oil along the oiled shorelines. Results showed that vegetation stress was restricted to the tidal zone extending 14 m inland from the shoreline in September 2010. Four indexes of plant stress and three indexes of canopy water content all consistently showed that stress was highest in pixels next to the shoreline and decreased with increasing distance from the shoreline. Index values along the oiled shoreline were significantly lower than those along the oil-free shoreline. Regression of index values with respect to distance from oil showed that in 2011, index values were no longer correlated with proximity to oil suggesting that the marsh was on its way to recovery. Change detection between the two dates showed that areas denuded of vegetation after the oil impact experienced varying degrees of re-vegetation in the following year. This recovery was poorest in the first three pixels adjacent to the shoreline. This study illustrates the usefulness of high spatial resolution airborne imaging spectroscopy to map actual locations where oil from the spill reached the shore and then to assess its impacts on the plant community. We demonstrate that post-oiling trends in terms of plant health and mortality could be detected and monitored, including recovery of these saltmarsh meadows one year after the oil spill.

Show MeSH
Related in: MedlinePlus