Never mind the wildfires, how about the algal bloom

Yellowknife, never a city to do things by halves, has decided to have an algal bloom to accompany this week’s general sense of lingering wildfire dread.

The NWT government’s Department of Environment and Climate Change posted to Facebook about the bloom on Thursday, a notice that got nearly 200 shares in a matter of hours as people found something that wasn’t a fire to worry about.

Here are the basics: the algal bloom, which looks like a blue-green kind of mist in the water, turned up near Negus Point (down the Yellowknife Bay shoreline if you went south from the Con dock area) on Wednesday.

Since then, it has dissipated into Yellowknife Bay, which included a brief waft past some houseboats before moving away into parts unknown.

As of Thursday afternoon, there is no report of any algal bloom remaining in the bay. But it turned up once, so there’s always the prospect of it turning up again in the near future.

Here’s a brief guide to what it is, what’s in it, and how concerned you should be.

Please tell me more about this fresh hell

It isn’t that bad. Put your evacuation kit down.

It’s a cyanobacteria bloom and no toxins were found in testing, “indicating the water remains safe,” the Department of Environment and Climate Change stated in a follow-up advisory.

Algal blooms happen when the water gets very warm and there’s a lot of sunlight. All that’s happening is a rapid increase in the amount of algae in the water, spurred by exactly the right conditions.

“This year the combination of unusually warm water temperatures, less flow through the Yellowknife River, and the recent sustained south winds may have contributed to increased algae in Yellowknife Bay,” the department speculated.

If my dog or I touch it, drink it or look at it the wrong way, what happens?

Probably not a lot but cyanobacteria, also imaginatively known as blue-green algae, can produce toxins (not always – and apparently not in this instance), so the safe thing to do is avoid it.

Try to keep your pet away from it, but if your dog insists on going full Steve Zissou, it is not an automatic death sentence. Obviously, in that circumstance, monitor your pet’s health closely and get help if anything seems at all amiss.

“This is blue-green algae bloom, we have confirmed the species,” said Jeffrey Cederwall, an aquatic quality scientist at the NWT government.

“The toxin results came back as non-detect, so at the present time there is no immediate risk to public or pets, but this species of algae does have the potential to produce toxins.”

Chris Cunada, a transboundary aquatic ecosystem scientist at the GNWT, added: “Cyanobacteria can produce a toxin you would want to avoid. However, just because they can produce the toxin, doesn’t mean they will produce the toxin. We found there to be no detectable levels of the toxin.

“In this case, it is not a risk.”

The formal advice from the department is to err on the safe side.

“Residents and waterway users around Yellowknife Bay are advised to avoid swimming in the affected areas and to keep pets away,” the department stated, though staff noted there is currently no affected area as the first bloom has dissipated.

“Collecting the water to treat for drinking and cooking is not recommended,” the department continued, referring to any water containing that blue-green mist or surface scum.

“Regular water use can resume once the algal bloom is no longer visible.”

But it might come back?

Yes, it might well come back. Algal bloom is a bit more common later in the year, and a bloom like this in Yellowknife Bay is unusual, but this has been spotted before.

“Previous small algal blooms have been observed in Great Slave Lake near the Mirage Islands and in bays on the North Arm, and may arise again through August or early September,” the department stated.

“Algal blooms are normal. Algae are just water plants and they like it when the water’s hot and there is lots of sun,” said Cunada. “They do occur, but not always so intensely. What’s unusual is to get such a dense bloom … and for it to be right here spreading out from Negus Point.”

Cederwall added: “We’re having an unusually warm year this year, driving the water temperatures up. It is possible that this could be seen later this season, so we wanted to give people an advisory that if you do encounter a similar surface scum that looks like this, just avoid that area, as we can’t confirm [the presence of toxins] immediately at all times.”

Samples are being regularly collected to continue monitoring for any new bloom.