December 18, 2010 - Yucatan Peninsula

Tropical Storm Karl (13L) approaching the Yucatan Peninsula

A luminous, swirling halo of light green and brilliant turquoise borders the quiet green and tan lands of the Yucatan Peninsula on December 12, 2010, when the Moderate Imaging Spectroradiometer (MODIS) aboard the Terra satellite passed overhead, capturing this stunning true-color image. The colorful and milky swirls extend over the shallow waters of the Bay of Campeche, part of the Gulf of Mexico.

The swirls of green, blue and milky white are probably primarily suspended sediment. As sediment swirls in currents, it scatters light and changes the color of the water. The exact color depends on type of sediment, as well as the depth. The deeper the particles, the less light is reflected and the darker and less luminous the color appears. In this image, the chalky white color most likely represents particles of calcium carbonate, originating either from shell-building marine life, such as coral, or from dissolved carbonate rock from the karst topography of the area.

Some of the color, especially the greens, may come from phytoplankton, which are tiny plant-like organisms which live in the sun-lit surface waters of the ocean. The upwelling of water from currents, as well as runoff from land, enrich the waters with nutrients and create a favorable breeding ground for phytoplankton. The Campeche zone is home to about 159 species of phytoplankton, primarily diatoms (greater than 80%) and dinoflagellates. The concentration of these organisms increase in the northwind season (late fall to winter), which is the season of greatest environmental instability in the region.

Image Facts
Satellite: Terra
Date Acquired: 12/11/2010
Resolutions: 1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC