A major red tide bloom extends more than 100 miles along Florida's Gulf coastline, and reaches more than 30 miles off shore. The harmful algal bloom has killed many thousands of fish and has had an impact on the shell fishing industry in a number of the state's bays.
The poisonous bloom of single-celled algae—called Karenia brevis—is relatively harmless under normal conditions when its concentration is about 10 cells per liter of water. But recent measurements show that there are currently between 100,000 and 1 million cells per liter in some of Florida's Gulf Coast waters. When K. brevis concentrations reach 5,000 cells per liter, the toxin they emit builds up within shellfish to the point where they can be harmful to humans. At 500,000 cells per liter, the toxin is so abundant it begins to kill fish in the water.
This true-color image was acquired on December 22, 2001, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. Notice the dark reddish color of the ocean, particularly concentrated around Estero Bay (toward the south) and Apalachee Bay (toward the north).
Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC