An abnormal bloom of toxic red algae is coloring the waters that wash the coastline southwest of Florida these days, killing fish. The phenomenon, which is described as a “red tide,” is typically fall but this year has occurred in winter probably due to climate change.
Many people, writes the Washington Post, have also complained of respiratory irritation. Toxic algae form in the waters offshore, move to the shore and begin to rot as other substances surface from the ocean floor in a process called “upwelling,” regurgitation of the sea.
And as they accumulate and concentrate they color the water red. In people, in addition to respiratory crisis, exposure to toxins released into the air can cause cold-like symptoms and eye irritation while in fish they eventually paralyze the gills.
The algae also kill birds, especially those that dive and feed on fish exposed to the toxins. Sea turtles, manatees and dolphins have also been victims of red tide.
A typical fall phenomenon, this year it occurred in winter instead, likely as an effect of climate change, according to the U.S. Environmental Protection Agency, which can cause harmful algal blooms to occur more frequently and even more intensely.
“The changing climate means there are warmer water temperatures and more extreme storms leading to greater stormwater runoff,” writes the Washington Post, and the combination of these conditions is the primary cause “for these large algal blooms.” Indeed, in recent weeks Florida has experienced warmer-than-usual air and water temperatures “ranging from 5.4 to 10.8 degrees above average.”