Oil on water has many appearances. In this photo-image, acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite on June 7, 2010, at least part of the oil slick is pale gray. A large area of oil is southeast of the Mississippi Delta, at the site of the leaking British Petroleum well. Traces of thick oil are also visible farther north.
Not all of the oil that is in the Gulf is visible here. The image shows regions of heavy oil where the oil smoothes the surface and reflects more light than the surrounding water. Lighter concentrations and streamers are not visible. The Deepwater Horizon Unified Response reported oil washing ashore and immediately offshore in eastern Alabama and northwestern Florida on June 7, and this oil is not visible in the image.
Several other features may mask the oil in the image. Pale white haze (possibly smoke from fires in Central America) hangs over the Gulf, partially obscuring the view of the oil slick. The oil slick also blends with sediment washing into the Gulf from the Mississippi River. The sediment plume is tan and green. Because the sediment also reflects more light than clear water, it may be masking the presence of oil in the water. West of the mouth of the Mississippi River, sunlight reflecting off the surface of the water (sunglint) turns the water silvery white. In this region, it is difficult to see sediment and oil, but NOAA maps of the extent of the oil spill on June 7 report oil throughout sunglint region.
The large image provided above is the highest-resolution version of the image available. The MODIS Rapid Response System provides twice-daily images of the Gulf of Mexico.
NASA image courtesy the MODIS Rapid Response Team at NASA GSFC. Caption by Holli Riebeek.