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Small cells make a big scene. A state of emergency has been declared in southern Florida after an algal bloom has released high levels of toxins into water.

NASA’s Landsat 8 satellite captured the bright green stripes of a huge algal bloom in Lake Okeechobee. The bloom has spread to cover 85 square kilometres, .

Over the last two weeks, Florida governor Rick Scott has  a state of emergency in a total of four counties whose waterways have been contaminated, and  President Barack Obama to declare a federal emergency.

Algal blooms arise when nutrients like phosphorus and nitrogen, common fertiliser ingredients, end up in bodies of water. Algae take up the nutrients and reproduce rapidly at the water’s surface, choking off submerged plants that form the base of the ecosystem.

The genus of blue-green algae blooming in Florida, Microcystis, has toxins that can harm aquatic food chains, says at Florida Atlantic University in Harbor Branch. The fouled water stinks like rotten eggs as the cells die, he says.

Respiratory issues

“I’m sure it’s taking its toll psychologically as well as from a health perspective,” says at Florida Atlantic University in Boca Raton. “It’s really off-putting to people, not to mention the respiratory issues that lots of people can experience.”

Algae in Lake Okeechobee blooms every few years, but this year has been worse than usual, says Hanisak. High rainfall this winter forced water managers to release lake water through the St. Lucie Canal, which runs to the Atlantic Ocean. This spread the affected water to the canal’s watershed and saltwater estuaries.

In a press release, Scott the federal government for failing to maintain the Herbert Hoover Dike, which keeps the lake’s water from overflowing into the Indian River Lagoon and Caloosahatchee river.

Gawlik says that the state shouldn’t be surprised by the bloom – nutrients have been building up for years.

“I’m a little bit tickled by our governor asking for this to be declared a federal disaster,” he says. “������ýs have been saying for decades, ‘we’ve got to clean up this water, and if you don’t these kinds of things can happen.’”

He says the region needs to build more wetlands that can filter out pollutants, and should reconnect Lake Okeechobee with the Everglades to hold excess water in rainy years, as it did historically.

Read more: Ultrasound weapon wipes out toxic algal blooms