Red tide and a blue-green algae outbreak are fouling hundreds of miles of coast, killing fish and driving tourists away from beaches. Some of the causes are natural, but human actions play a big role.
Toxic algae blooms like the intense one now fouling Florida’s waterways harm wildlife and people in various ways. They're also on the rise.
They give us part of the air we breathe but microscopic phytoplankton can also be toxic. They are also on the move thanks to climate change so a new Australian database hopes to monitor any changes.
The same conditions – ultimately tied to nutrient runoff – that created the damaging toxic blooms and dead zones in US waterways of recent years are forecast to return this year.