Poisonous Algae Blooms Threaten People, Ecosystems Across U.S. Serious algae outbreaks have hit more than 20 states this summer. Algae blooms aren't unusual. But the frequency, size and toxicity now are worse than ever, and changes in climate are partly to blame.

Poisonous Algae Blooms Threaten People, Ecosystems Across U.S.

  • Download
  • <iframe src="https://www.npr.org/player/embed/491831451/491848138" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript


Serious algae outbreaks have hit more than 20 states this summer. They are shutting down beaches in Florida, sickening swimmers in Utah and threatening ecosystems in California. The blooms are a normal part of summer, but the frequency, size and toxicity are worse than ever. From San Francisco, Lesley McClurg of KQED reports.

LESLEY MCCLURG, BYLINE: Water managers are rattled.

BEV ANDERSON: Everyone's on edge with the cyanobacteria.

MCCLURG: Emails reporting cyanobacteria, or blue-green algae, outbreaks fill Bev Anderson's inbox every morning. She's a scientist with the California Water Resources Control Board.

ANDERSON: Oh, we're getting blooms all over the place this summer. We've got a massive bloom in Lake Elsinore, a lot of the East Bay Parks.

MCCLURG: Big reservoirs like Shasta Lake, Lake Oroville. In some places, it looks like someone poured a giant can of green paint into the water. And the smell can be rank. Anderson says California has posted danger signs at at least 30 lakes and reservoirs.

ANDERSON: Toxin levels are crazy.

MCCLURG: And at what level should we be worried?

ANDERSON: Twenty micrograms per liter.

MCCLURG: We should be worried at 20 micrograms per liter, and we're seeing 150,000 micrograms per liter.

ANDERSON: That's correct.

MCCLURG: But don't worry. Water districts carefully screen for toxins in drinking water. It's boaters and swimmers who are at risk.

Discovery Bay, a community an hour east of San Francisco, is normally buzzing with boats and jet skis. But this year, the waterfront has been eerily still for weeks. With disgust, Dave Holmes watches his white speedboat and blue kayak bob in mucky, green water.

DAVE HOLMES: We've been here since 2002. It is by far the worst we've ever seen.

MCCLURG: Down the street, another Discovery Bay resident regrets diving into the water in mid-July. Wade Hensley ended up in the hospital because his body went numb from the waist down. It's still numb.

WADE HENSLEY: And it was about three days of swimming - not constant but in and out - and they can't pinpoint exactly what it is.

MCCLURG: But county health officials did find microcystin in Discovery Bay, one of several toxins produced by algae. More typical symptoms are dizziness, rashes, fever and vomiting. Algae expert Bev Anderson blames a changing climate for the blooms, at least in part.

ANDERSON: We're getting higher temperatures than we've seen ever in the past. California had an unprecedented drought for the last five years which have the water levels very low in a lot of areas.

MCCLURG: And shallow water means warmer water. Add to this cocktail runoff from farms, golf courses and lawns. Algae loves fertilizers. And worst of all, Anderson says scientists are just starting to understand a problem they expect to escalate.

ANDERSON: Some areas have been monitoring and seeing blooms for decades, but they've never had toxins.

MCCLURG: Researchers are finding poisonous blooms in surprising places like mountain lakes and streams. So scientists are scrambling for solutions. The chemicals that kill algae can help temporarily, but they can also backfire by promoting other toxins. When it comes to swimming, Anderson's advice is simple.

ANDERSON: If in doubt, stay out. Don't go in. Don't let your dogs in.

MCCLURG: There's nothing to do now but wait for the green muck to disappear and hope a cold winter kills it off. For NPR News, I'm Lesley McClurg in San Francisco.

Copyright © 2016 NPR. All rights reserved. Visit our website terms of use and permissions pages at www.npr.org for further information.

NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.