Black Water Turns the Tide on Florida Coral

A patch of “black water”spanning over 100 kilometers [60 miles] in diameter formed off southwestern Florida in early 2002 and contributed to severe coral reef stress and death in the Florida Keys. The “black water” contained a high abundance of toxic and non-toxic microscopic plants. When scientists examined the data collected by divers from the dark water area in the Florida Keys, they discovered a 70 percent decrease in stony coral cover, a 40 percent reduction of coral species, and a near-elimination of sponge colonies at two reef sites after the dark water passed. By examining satellite images and field survey data, they concluded that the coral reef ecosystem was stressed by microscopic organisms and toxins contained in the dark water.