Oh, drear, more gloom and bad cheer — that’s what you’re thinking if you’re a SAD Brit hunkered down in your centuries-old stone house staring out the fortress slit at yet another gray day. What is this mist before your eyes, tears or rain? So you punch on the computer and randomly search for sunny news. And the ad of your dreams pops up: “Bottled sunshine offsets winter blues.” It’s a promotion for a product called vitalMAX from some outfit in the United Kingdom.

“Shorter days and cold weather make most of us feel more tired and gloomy but the outlook for people prone to Seasonal Affective Disorder is even darker,” reads the ad. It reports that people with SAD undergo a brain transformation in which “their brain’s output of neurotransmitters (that fire off emotions, hormones and thought patterns, among other things) ‘switches off’ as daylight levels fall.”

Sunshine, says the ad, is the answer. A bit further down comes the pitch: “No-one has found a way to bottle sunshine yet, but Klamath blue-green algae comes closest. As the planet’s first photosynthesiser, Klamath’s blue-green algae is well-placed to transfer its stores of ‘condensed sunshine’ to us.”

Well, that’s funny, you think. Because, during your summer vacation to the Pacific Northwest of the U.S., you happened to be paddling around on the Klamath River enjoying some real sunshine when along came an official sort hammering up a notice on a nearby tree that said something pointed like, you remember hazily, “get out of the water now, it’s toxic because of the blue-green algae.” It was scary.

Googling about, you find that there are tons of companies pushing Klamath blue-green algae — a cure for all of life’s cruel blows, it seems. But then you replace the word “tonic” with “toxic,” and up come all the scary news stories about dogs dying of liver failure after swimming in the river, about tribal members unable to perform ceremonies and having to tell their kids to stay out of the water.

So what gives? Is Klamath blue-green algae toxic or tonic? Sad people everywhere want to know.

Susan Corum, water quality coordinator for the Karuk Tribe, says what the blue-green algae pushers are harvesting “is a different species species of blue-green algae” from the one — Microcystis aeruginosa — known to produce the toxin microcystin. And it’s true the companies mention one specific blue-green algae, called Aphanizomenon Flos-Aquae (AFA). “However, what they’re harvesting is out in the natural environment — upper Klamath Lake, and a canal,” says Corum. “And the problem is, harvesting from the wild, you can’t control what kind of species are combined in there.”

The Karuk Tribe regularly monitors water quality in the reservoirs above Iron Gate and Copco dams and in the Klamath River below the dams, where the toxic algae often rises above acceptable health levels. “When we send out samples to the lab, there’s never just one kind of algae species — you get from five to over 20 species,” says Corum.

That said, Corum notes that the blue-green algae harvesters cull their product from upper Klamath Lake, in Oregon. That’s good, for one, because the state of Oregon applies standards to algae harvesting, and, for another, because while the known-to-be-toxic algae M. aeruginosa is found in upper Klamath Lake, it doesn’t occur at the levels found lower in the river system. “But there’s other species that can be toxic, too,” says Corum. “I would be concerned about any supplement where they’re harvesting it from the wild.”

The “bottled sunshine” folks didn’t respond to an e-mail by press time. However, a consultant to Power Organics, one of the three harvesters of the blue-green algae AFA from upper Klamath Lake and an associated canal, said on Tuesday that of course their algae is a tonic, not a toxin. But “the microcystin issue is a serious one,” Gabriel Diamond says. He says the populations of different algae species fluctuate with the seasons, with blooms of the toxic M. aeruginosa typically peaking in the heat of summer and dying back to practically nil by late autumn. “We are not going to harvest until the microcystin species is nonvisible” under microscopes, he says. “We also have a microfiltration system that can separate out the microcystin. We were the company that developed this.”

Now, years ago, there was a serious flap over blue-green algae supplements. Someone died of liver failure, a company (not Diamond’s) got sued, and reports pro and con proliferated. Diamond says he doesn’t believe algae killed the person. But Craig Tucker, spokesman for the Karuk Tribe, says he figures the reports of toxic algae on the lower Klamath must be bad for the algae business, anyhow. “Now and then some snappy dressed person shows up at a water board meeting” to talk about the difference between their algae and the toxic stuff, Tucker says.

Diamond says his company’s used to the bad press by now. “I recommend this stuff to my friends,” he says.

Tucker, on the other hand, doesn’t do any health supplements. “I believe in three square meals a day,” he says.