Algae blooms produce toxins, public health concerns in alpine lakes

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ALPINE COUNTY, Calif. (KOLO) - Just off Highway 88 below Carson Pass, fed by snow pack runoff, Red Lake is an alpine gem in the Eastern Sierra.

"When you drive over Carson Pass in the spring it's beautiful, clear. It's the pristine alpine lake you'd expect to see in the spring time," says Alpine County Health Officer Dr. Rick Johnson.

But at the moment, Red Lake, named for the mountain looming over it, more resembles a lake of pea soup.

A bloom of blue-green algae is to blame, and that pea-soup color is like a flashing red light. If it doesn't get your attention, the danger signs will.

You see, at the moment Red Lake is actually toxic. It's unlikely you'd want to swim in it, even less likely you'd drink it. Expect skin irritation and gastrointestinal problems if you do. It is, however, potentially lethal to man's best friend.

"The toxin is especially harmful to dogs. Dogs can get convulsions and die after swimming and drinking the water or licking their fur."

There's no evidence wildlife is affected. It apparently poses no threat to the fish, though here at Red Lake, fishermen are advised not to take their catch home.

Down below at Indian Creek Reservoir, the toxins are at the warning level. It's still best for you and your dog to stay out of the water. Any fish you catch should be safe to eat once cleaned well.

The algae in these lakes is an ever present fact of nature, here and just about everywhere. Usually harmless and little noticed. And locals will tell you a bloom at this time of year after a long summer of warm days and sunshine is something they've seen time and time again.

But Dr. Johnson says that can change.

"When you have a heavy bloom or overgrowth of the algae it begins to produce the toxin and that's when it becomes a concern."

What isn't known is why it's happening now.

There are theories, but no conclusions.

"Whether it's natural. Whether its global warming or climate change. Whether it's something that's coming down from the highway. Whether it's something that's coming down in the runoff from the snow melt we just don't know, but some conditions have changed in the lake in the last few years."

A mystery to be solved and an important one too for areas like Alpine County where recreation is a big part of the lifestyle and economy.

In the meantime, take note of the warnings. Johnson says, "When you see a lake that becomes green like this you need to take some caution."

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