The algae is currently the subject of a four-year study by a University of Manitoba team that includes 22-year-old masters student Ainslie Macbeth.
"It's thick. If you feel it, it's almost like matted dog hair," says Macbeth as she lifts algae from the water of Betula Lake.
With her red hair and research into a strange phenomenon, Macbeth calls to mind fictional scientist Agent Dana Scully of TV's X-Files fame.
But this is no fiction. Black algae is insidious. Its discovery here in Whiteshell Provincial Park is the first known case in Canada.
Unlike other algae that are translucent and float on the surface, black algae grows densely on lake bottoms, especially on sand, and it's choking Betula and White lakes, about 160 kilometres east of Winnipeg.
It also spreads quickly. In just the past year, black algae has travelled half a kilometre, moving west to east across Betula Lake.
In fact, it's crawling right up the beaches. The public beach at Betula was re-sanded just a week earlier, but it's already blotched by clumps of black algae. Resort owners have to regularly groom the beaches.
"It wraps around your legs when you go into the water. It just feels horrible on your legs," said Macbeth, a botanist who heads the field research. "It grows into a mat on the lake bed."
It also clogs outboard motor propellers. Some people row their motorized boats away from shore to start them. Until now, black algae -- its Latin name is Lyngbya wollei -- has been strictly a Florida phenomenon, where millions of dollars have been spent to fight it, and where it has done great harm to the shellfish industry.
How it got into two Manitoba lakes is the $64,000 question. The only other case of black algae anywhere close by is in a lake in Minnesota. The best guess is that black algae was transported into Manitoba by snowbirds who took their boat on a vacation to Florida. The algae may have been brought back to the province on the bottom of a boat or some other piece of aquatic equipment.
"I think that's a very good possibility," said Gordon Goldsborough, University of Manitoba botanist, who oversees Macbeth's four-year research project. "I have trouble understanding how else something that is widespread in Florida can leap-frog across the continent into Manitoba."
Like the spread of SARS and the West Nile virus, the unexpected arrival of the algae here may be "another illustration that humans in the globalized society are transporting things all over the world," Goldsborough said.
He plays down reports that have linked black algae with paralytic shellfish poisoning. In Florida, black algae produces a neurotoxin that is being blamed for paralysis in some people who consumed mussels there.
Preliminary tests in Betula and White lakes are showing no evidence of neurotoxins in the water, said Goldsborough. More tests will be conducted, but Goldsborough hopes people will keep their cool.
"When some people heard (about neurotoxins), we had people saying, 'Oh, my dog died a few months ago and we didn't know why.' Right now, it's fairly clear that black algae here is strictly an aesthetic issue," he said.
For example, the algae could give fish an off flavour, and it can cause lake water to smell.
The province is taking a wait-and see approach, said a spokesman for Manitoba Conservation. Macbeth and Goldsborough receive funds from the provincial sustainable development innovation fund.
"They have to do research before we can do an action plan," a government spokesman said.
The main issue right now is to stop black algae from spreading into other Manitoba lakes. The trouble is it sticks like spitballs to anything it touches, which makes it very transportable into other waterways. It is also very fibrous, with fine filaments that easily cling to material and can be carried away unnoticed. Signs at boat launches at Betula and White warn boaters to wash down their watercraft and trailers before launching in other lakes.
Macbeth has tested 12 Whiteshell lakes in total, including some undeveloped lakes. She has not found black algae in any other Whiteshell lakes.
Macbeth's study is the first testing of water quality in the Whiteshell since 1973. Some preliminary results will be available next year.
One possibility is that black algae took root in Betula and White because they are shallow lakes, no more than three metres deep except for some deeper pockets. While direct sunlight kills the algae, it is capable of tremendous growth with a small measure of indirect sunlight. It may be that these lakes are the optimal depth for black algae to grow, said Macbeth.
"It's very competitive because it can use so little light to grow," she said.
No one seems to know when the black algae first appeared, but it has grown rapidly in recent years, said Don Mitchell, a year-round cottager at Betula and a director with the Whiteshell Cottagers Association.
"It's like black, greasy hair when you pull it out, and it's pretty gross. It's creepy," said Mitchell, who has been going to Betula Lake for over 30 years. "We are very concerned.