Study finds widespread land losses from Gulf of Mexico oil spill

November 18, 2016 by Alan Buis, Jet Propulsion Laboratory
2010 photo of a shoreline in Bay Jimmy, Plaquemines Parish, Louisiana, impacted by the BP Deepwater Horizon oil spill. Oil weakens and kills vegetation, leading to the loss of roots that help hold soil together. Credit: Bruce A. Davis, Department of Homeland Security

Dramatic, widespread shoreline loss is revealed in new NASA/U.S. Geological Survey annual maps of the Louisiana marshlands where the coastline was most heavily coated with oil during the 2010 BP Deepwater Horizon oil spill in the Gulf of Mexico.

Following the spill, the length of shoreline that receded more than 13 feet (4 meters) a year quadrupled compared to the year before the spill. The land losses occurred mainly in areas where oil had washed ashore during the spill.

A research team led by Amina Rangoonwala of USGS used airborne remote sensing imagery to analyze shoreline loss across nearly the entire upper Barataria Bay, located on the western side of the Mississippi River Delta, beginning a year before the spill and extending for 2.5 years after it. To determine whether the was likely to be caused by the oil, they also compared shoreline loss linked to the deposited oil with shoreline erosion caused by high waves from Hurricane Isaac in 2012.

The team found that although erosion occurred at isolated sections of the shoreline before the spill, the pre-spill shoreline (as analyzed from 2009 to 2010) was largely stable. In the first year after the spill (2010 to 2011), the erosion pattern changed dramatically from isolated to widespread. Erosion occurred mainly along shorelines with documented heavy to moderate oil coating. In the second year after the spill (2011 to 2012), the higher loss rates extended to areas that had less oil coating. Oil is known to weaken or kill vegetation, leading to loss of the roots that help hold soil together.

Barataria Bay, Louisiana, shoreline changes, June 2009 to Oct. 2012, after the oil spill and Hurricane Isaac: a) high loss Year 1 post-spill, decreased loss Year 2, little loss after Isaac; (b) high loss Years 1/2 post-spill, little loss after Isaac; (c) high loss that intensified during Isaac. Credit: USGS/NASA-JPL/Caltech

In August 2012, two months after the two-year post-spill period, Hurricane Isaac made a direct hit on Barataria Bay. Erosion rates measured in the four months after the hurricane were higher than those measured after the spill. But this erosion occurred primarily on just a few shorelines that before the spill showed evidence of heightened susceptibility to wave-generated erosion.

"Our study uniquely shows that the patterns of shoreline recession seen in this region can be directly related to distinctly different causes: broadly dispersed erosion due to oiling from the Deepwater Horizon spill, and enhanced, but spatially limited, erosion due to intense storm impacts," said Rangoonwala.

The wetland impacts of the spill documented by the team included both the loss of wetlands due to shoreline erosion, and island fragmentation, where small islands are broken into even smaller islands, creating more shoreline. Land lost from fragmentation is unlikely to be reestablished, particularly in this part of the Mississippi River delta where levees prevent an influx of new sediments from the river. This will alter natural coastal defenses against flooding.

Map of Northeastern Barataria Bay, Louisiana, showing shores oiled by the Deepwater Horizon oil spill during May to July 2010. The severity of oiling is indicated by the colors. The information is derived from a 2014 NOAA Shoreline Cleanup Assessment Techniques (SCAT) map. Credit: USGS/NOAA/NASA-JPL/Caltech

The images collected in the annual surveys and following Hurricane Isaac were obtained from NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, California. UAVSAR flies on a C-20A research aircraft based at NASA's Armstrong Flight Research Center facility in Palmdale, California. UAVSAR's polarized radar produced detailed representations of the marsh, which USGS scientists then used to develop a process to analyze the shoreline recession by mapping the change in shore location.

"Through this process, USGS and NASA scientists developed a repeatable, quantitative mapping method that will allow us to monitor after oil spills in the future," said study co-author Cathleen Jones of JPL. "Being able to compare shoreline losses in a year without any major storm to losses both after the Deepwater Horizon oil and after the hurricane was essential to correlating the erosion of the marsh to its underlying causes."

The study, "Wetland recession in the Mississippi River Delta from petroleum oiling and cyclonic storms," is published in the journal Geophysical Research Letters.

Explore further: Deepwater Horizon oil spill caused widespread marsh erosion, study shows

More information: For more information on UAVSAR, visit uavsar.jpl.nasa.gov/

For more information on NISAR, visit nisar.jpl.nasa.gov/

Related Stories

Gulf oil spill research featured in special issue

November 2, 2016

The Deepwater Horizon oil spill was not only the largest ecological disaster in the U.S., but it has become the most scientifically researched oil spill. Six years since the disaster, researchers from various fields have ...

One beach reopens after Los Angeles sewage spill

July 21, 2016

A mile of Southern California shoreline that was closed amid fears involving a sewage spill 20 miles away was reopened Thursday after two consecutive bacteria tests came back clean.

Recommended for you

Nanoscale Lamb wave-driven motors in nonliquid environments

March 19, 2019

Light driven movement is challenging in nonliquid environments as micro-sized objects can experience strong dry adhesion to contact surfaces and resist movement. In a recent study, Jinsheng Lu and co-workers at the College ...

OSIRIS-REx reveals asteroid Bennu has big surprises

March 19, 2019

A NASA spacecraft that will return a sample of a near-Earth asteroid named Bennu to Earth in 2023 made the first-ever close-up observations of particle plumes erupting from an asteroid's surface. Bennu also revealed itself ...

Levitating objects with light

March 19, 2019

Researchers at Caltech have designed a way to levitate and propel objects using only light, by creating specific nanoscale patterning on the objects' surfaces.

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

xstos
5 / 5 (2) Nov 18, 2016
Brings a new meaning to shitting in your back yard (for profit).
gkam
3 / 5 (4) Nov 18, 2016
Polluters do not care as long as they prosper. They see it as a zero sum game, and the more they get, the happier they are. See, . . they beat you by having more money, and all it took was to lose their character.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.