Did Humans Exacerbate the Red Tide Devastating Florida's Beaches?

Maya Wei-Haas reports on the red tide devastating Florida's beaches this year, and asks the question of how much blame human activity can be assigned to the devastation.

Here's how Wei-Haas describes the cause and effect of the red tide:

Thousands of sea creatures now litter many of southern Florida’s typically picturesque beaches. Most are fish—mullet fish, catfish, pufferfish, snook, trout, grunt, and even the massive goliath grouper. But other creatures are also washing ashore—crabs, eels, manatees, dolphins, turtles, and more. It's a wildlife massacre of massive proportions. And the cause of both the deaths and toxic, stinging fumes is a bloom of harmful algae that scientists say is the region’s worst in over a decade.

The red tide takes its name from its rust-brown color, according to Wei-Haas, and in Florida "the culprit is usually the tiny, plant-like alga known as Karenia brevis, which produces toxins, dubbed brevetoxins, that cause both gastrointestinal and neurological problems when eaten."

Records of red tides in Florida date back to 1500, but this year's devastation has inspired a debate about whether humans are responsible for the scale of the devastation. The Karenia brevis is attracted to the Florida coast for natural reasons like salinity and temperature, but other researchers "believe the algae feeds on the nutrient-rich agricultural runoff from land, causing it to stick around for longer and rage more intensely," according to Wei-Haas. Red tides also tend to follow massive storms, which occur naturally, of course, but also have begun to increase in frequency and intensity due to the effects of human-caused climate change.