Landsat Image: Mississippi River Delta
This Landsat image of 3 October 2011 shows the Mississippi River Delta, where the largest river in the United States empties into the Gulf of Mexico.
In this false-colour image, land vegetation appears pink, while the sediment in the surrounding waters are bright blue and green. The delta is known as the 'bird-foot' delta because of the shape created by the channels extending outward.
The size of the Mississippi River Delta built over millions of years owing to sediment deposition. The tons of sediment carried by the river system created the wetlands in southern Louisiana, which are home to many endangered species and help to protect the mainland from hurricane winds by acting like speed bumps.
Over the last several decades, however, the delta's sediment load has been drastically reduced by natural and man-made factors. Extensive oil and gas extraction causes the subsidence of the delta and wetlands, and rising sea levels increase erosion as the fresh water vegetation dies due to the influx of salt water.
Currently, a chunk of land the size of a football field is lost about every half an hour. In 2005, Hurricane Katrina destroyed much of the wetlands, while the 2010 Deepwater Horizon oil spill affected natural wildlife and the fishing industry.
This area is of significant economic importance, providing about 17% of the oil supply in the US, and 16% of fisheries harvest, such as shrimp, crabs and crayfish. A third of the nation's oysters come from the Mississippi River Delta.
The Thematic Mapper on Landsat-5 is jointly managed by NASA and the US Geological Survey. ESA supports the Landsat series as a Third Party Mission, meaning it uses its ground infrastructure and expertise to acquire, process and distribute Landsat data to users.
ESA has recently opened archived Landsat data for use by the scientific community, free of charge.