Pawnee Lake algae
The remote sensing center at the University of Nebraska-Lincoln collected this hyperspectral image of Pawnee Lake west of Lincoln. The darker areas show a higher concentration of chlorophyll-a, which indicates algae, but the image can’t show whether the algae is toxic.

Toxic algae -- that yucky green stuff that has killed dogs and sickened humans -- has kept Bob and Leslie Lewis from boating and fishing on some local lakes.

Bob likes to fish but the algae gets on his line.

Said Leslie: "It looks just like green paint."

The couple even avoided pleasure boat rides when lakes were posted "because it smells so bad and gets on the boat," she said.

But the summer of 2010 may be a better summer for water sports.

Toxic algae content in some lakes rose during the height of the drought. So it's certainly possible it will drop as the lakes fill up.

But there's no guarantee.

"With the random nature of algae, I hesitate to make any predictions," said University of Nebraska-Lincoln scientist Tadd Barrow.

While low water means warmer water and more sunlight for algae growth, additional water flowing into lakes may bring more phosphorus, which algae need to thrive, scientists say.

But so far this year, there have been no health alerts at any of the 46 Nebraska lakes monitored by Department of Environmental Quality staff.

Last year, there were five lakes with alerts, one for eight weeks and the rest for two, said the DEQ's Brian McManus.

During the height of toxic algae in 2005, 12 lakes had health alerts, including Pawnee, which had toxic algae alerts for 14 weeks.

"For Pawnee, that was a bad year," McManus said.

You find blue-green algae any time, particularly in warmer summer water, said John Lund, surface water unit supervisor for the DEQ. But that doesn't mean there will be toxic algae.

"It's kind of a guessing game as to why sometimes we have toxic algae and sometimes we don't," Lund said.

"I've called it the $64,000 question," he said.

There is a difference between toxic algae and the nontoxic kind.

If it looks as if someone has dumped a bucket of green paint into the lake, don't let your dog swim, Barrow said.

If there is something stringy and hairlike on your fishing line, that's nontoxic.

Toxic algae has been around forever, but Nebraska agencies first recognized it in 2004, when dogs died after drinking water from lakes in Sarpy County.

It's possible scientists didn't attribute to toxic algae previous dog deaths or complaints from swimmers about lesions or itching, Lund said.

"Maybe we just misidentified the problem."

Pets and livestock have died after drinking water with toxic algae. Humans can get flulike symptoms, rashes, even skin lesions.

There have been lakes in western Nebraska with toxic algae problems, but most problem lakes are in the east, which probably relates to nutrients, Lund said. With more erodible soil and aggressive row crop farming, more nutrients run off and into the water, he said.

Three state agencies are cooperating on toxic algae issues.

DEQ tests public lakes and posts results on its website, the Department of Health and Human Services handles health alert notices and the Games and Parks Commission posts beaches.

UNL staff members educate the public, provide test kits for private lake owners and study the algae.

Reach Nancy Hicks at 402-473-7250 or nhicks@journalstar.com.

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