Algal blooms are responding to nutrient enrichment and global warming by becoming ever more toxic, according to research from OSU postdoctoral scholar Timothy Otten that was published today in Science.

Algal Blooms

“Cyanobacteria are basically the cockroaches of the aquatic world,” said Otten in the OSU press. “They’re the uninvited guest that just won’t leave.”

Toxic algal blooms

Otten explains that it’s not the toxicity itself that gives these types of algae a competitive edge. The cyanobacterial toxins protect the algae from oxidative stress; being harmful to other forms of life is just a side effect. Unfortunately, once toxic algal blooms take hold in a lake they are likely to return year after year.

“When one considers their evolutionary history and the fact that they’ve persisted even through ice ages and asteroid strikes, it’s not surprising they’re extremely difficult to remove,” he said. “For the most part, the best we can do is to try to minimize the conditions that favor their proliferation.”

So far, about a third of all U.S. lakes 10 acres in size or larger already have toxin-producing cyanobacteria, and the combination of rising temperatures, nutrient runoff, dam construction, and droughts will likely push that number higher. While not all of those contributing factors can be mitigated with better policies, some of them can and should.

Algal blooms posing threat to health

Aside from a general desire to conserve the environment, these blooms pose a serious threat to human health. People who spend a lot of time on the water, such as fisherman, are repeatedly exposed to the water as well as what’s in it, and if toxicity levels are high enough in lakes used for drinking water, entire populations could be in danger.

“Water quality managers have a toolbox of options to mitigate cyanobacteria toxicity issues, assuming they are aware of the problem and compelled to act,” Otten said. “But there are no formal regulations in place on how to respond to bloom events.”

Otten thinks that people need to be better informed about toxic algae so that reasonable safeguards can be put into place and standard procedures can be put into place for water quality teams to follow in case of contamination.