As the return of warm weather brings the return of bacteria blooms on New Hampshire lakes, researchers are looking into whether the blooms are happening more often and whether we should be more concerned about health effects.
Last week, the New Hampshire Department of Environmental Services issued two lake warnings, one at Elm Brook Park in Hopkinton and one at Silver Lake in Hollis – the latter of which was activated, rescinded when the bloom went away and then reactivated when it returned.
That’s nothing unusual, said James Haney, a researcher with the New Hampshire Agricultural Experiment Station at UNH and a professor of biological sciences who has been studying cyanobacteria (often incorrectly called blue-green algae) for decades.
“This is the normal season. It usually starts in June,” Haney said.
What’s uncertain, Haney said, is whether there are more blooms happening or whether we’re just more likely to notice them.
“More people are reporting it than before, and that complicates it,” he said.
Still, Haney said, there are indications that more blooms are happening and that they’re lasting longer, linked to the changing climate.
“We know that there’s a tendency to have warmer, earlier springs in general, and lakes in summer get above 25 (degrees Celcius, or 77 degrees Farenheit) for longer periods than they ever did before.
“That’s the temperature at which cyanobacteria have their optimum growth rates,” Haney said. “It used to be, it would happen at the peak of the summer; now it can go on for weeks.”
Cyanobacteria live in most New Hampshire lakes. The right conditions cause populations to explode to the point that millions of the cells die, losing their buoyancy control and floating to the surface, creating slimy, algae-like mats.
Health problems arise in people and pets because the dying cells erupt, releasing toxins. Depending on the species of bacteria, time of year and size of the bloom, these toxins can produce health effects ranging from rashes to serious liver problems.
Health officials caution people to stay away from the blooms, so they don’t accidentally swallow any of the toxins, and to keep away pets – particularly dogs, which are likely to drink the water.
As part of the UNH project, Haney said researchers are studying the toxicity of blooms over the course of the summer.
“We’re trying to see if these early species of cyanobacteria, those that appear earlier in the year, are as toxic as the later ones,” he said “It’s only a hypothesis, it’s only that, but if it’s true then it could make a difference.”
Haney’s lab is also working to develop model that can predict the toxicity of a bloom from the amount of a blue pigment known as phycocianin present.
“If we can develop a relationship between the (pigment) and the amount of toxin, it would allow for a very simple test to determine toxicity. … You’d shine a light in that’s absorbed only by the blue pigment, and that would tell you,” he said.
In recent years, evidence has cropped up linking cyanobacteria toxins with ALS, often called Lou Gehrig’s Disease, an untreatable condition that slowly destroys nerve cells in the brain and spinal column. A cluster of ALS cases around Mascoma Lake in Hanover has drawn considerable attention and continued research.
Haney pointed to an amino acid called BMAA found inside some species of cyanobacteria. It has been linked to both ALS and Alzheimer’s disease, and is being used to create Alzheimer’s-like symptoms in chimpanzees so that potential treatments can be tested.
“We have measured (BMAA) in a number of New Hampshire lakes and in some of the fish, also are measuring it in the blood of some loons,” Haney said.
But if BMAA is causing ALS in humans, he said, there’s a question: “How does it get from the lake to the people?”
Perhaps it is being ingested when people eat fish or swallow water, but there’s another possible – and alarming – route.
BMAA is a very small molecule, so small that it can be carried aloft as part of evaporation, then float in the air where it could potentially be inhaled.
UNH researchers are currently studying this possibility, testing to see how much BMAA exists in the very fine spray, or aerosols, produced by normal lake evaporation.
Haney acknowledged that it “wouldn’t be great news” if we discover that a toxin can be inhaled just by being near a lake. But, he added, “not knowing isn’t great news either, if we’re also getting sick from it.”
Further, even if BMAA can be aerosolized and inhaled, we have to explain why ALS is so rare. “Why is it that most people don’t get it, living near a lake?” he asked.
For the time being, however, the advice for cyanobacteria blooms remains the same: Don’t get close.
“If you had a rattlesnake on the beach, you avoid it – right? – and hope it goes away,” he said. “That’s what we recommend.”
(David Brooks can be reached at 369-3313 or dbrooks@cmonitor.com or on Twitter @GraniteGeek.)
