The Caribbean Sea
The vivid azures and emeralds in this image of the Gulf of Mexico and the Caribbean Sea reveal life at the coastal margins. The bright blues on the right side of the image indicate the presence of the shallow waters of the Little Bahama and Great Bahama Banks, from top to bottom, respectively.
A third, much smaller bank (Cay Sal) -- sandwiched between Florida and Cuba -- is also visible. The banks consist of a mix of mostly white sand and submerged aquatic vegetation; their depth ranges from 3-9 meters (10-30 feet), compared with the surrounding deeper waters that range from 60-600 meters (200-2000 feet).
Depending on water quality, sunlight is only able to penetrate to a depth of about 200 meters (650 feet) at best, while in some places it can only reach a meter or two (3-6 feet). It is this very shallowness that makes marine ecosystems not only highly productive (because more light equals more photosynthesis) but also vulnerable to the influence of human activity.
Coastal development, sea level rise, pollution from industrial and agricultural activities, and even the wakes from motor boats can have an adverse impact here. Also visible in the image are resuspended bottom sediments off of the Gulf coast of Florida.
Runoff from the land surface carries eroded materials into the Gulf of Mexico; this is exacerbated by the flooding associated with hurricanes and other major storm events. Often, these sediments are brought back to the surface by deep ocean currents where they provide nourishment for phytoplankton, or tiny marine plants that live in the water column.