Coal Creek suddenly inundated with invasive form of algae

No definitive answer

It’s like an old Hardy Boys or Nancy Drew mystery. Title it The Mystery of the Crested Butte Rock Snot?

Several people in the last few weeks have noticed a green slime covering the rocks of Coal Creek that runs through town. It likely could be an algae known as Didymosphenia geminat, a fast-spreading single-cell (diatom) algae whose common name is “Rock Snot.” In fact, the snot can also exist as colonial algal mats and those can clog up the creeks and harm the fishing.
The fact that it is occurring essentially east of First Street in Coal Creek and not above that point is a mystery. The fact that it starts in the same area where a fuel oil leak was discovered two weeks ago adds to the mystery, but seems to be coincidental.
“There is good algae and bad algae and no one seems to know whether this is either,” said Crested Butte public works director Rodney Due. “There doesn’t seem to be any major impact right now and so the town is noticing it but not really worried about it. It’s a mystery to us at the moment.”
The scientists at the Rocky Mountain Biological Laboratory have noticed the algae in the area and elements remain a mystery to them as well. “It’s not just a local situation,” explained RMBL executive director Dr. Ian Billick. “It is a large-impact phenomenon happening all over the west and it has been increasing dramatically in streams over the last several years.” Billick said the RMBL scientists haven’t specifically looked at the recent Coal Creek outbreak.
RMBL began distributing pamphlets to fishermen several years ago asking them to be extremely careful when going between streams, because they can carry the algae and contaminate another waterway.
“About two years ago we started implementing strict protocols for all of our people going between streams,” he said.
Billick said there are several theories being debated between scientists about how the algae is increasing. “The algae seems to be changing its growth form,” Billick said. “Why that is happening is still up for debate. It seems to be worse as you get closer to Denver. Some people feel that the spring runoffs are slower, the water doesn’t scrub the algae off the rocks as well as it once did, and it has a longer season to grow.
“It is transforming streams across the west in pretty serious ways,” Billick continued. “Fish are impacted and don’t grow as fast, so fishermen see the impacts up close.”
In his scientific paper written this past summer, RMBL student Eric Ellison reports the algae cells divide in vegetative reproduction “and that can lead to the accumulation of thick, dense mats that can cover 100 percent of the stream bottom and can extend for more than a kilometer of a stream length. Stalks are often more than ten times the length of the diatom cell… and are resistant to degradation and persist after the death of the diatom cell that secreted it.”
In other words, the rock snot can grow fast and thick, and doesn’t easily go away once it is there.
Billick said the algae doesn’t present a human health hazard “but it does change how the streams work. It may be a short-term thing. We just don’t know. There are records of this algae in the area as far back at the 1960s but scientists really started noticing it up here three or four years ago.”
Coal Creek Watershed Coalition director Anthony Poponi said his group has taken samples of the algae and are waiting on a definitive determination of what is causing the increase in the algae this summer. “An algal bloom of this sort is usually related to phosphorous inputs,” said Poponi.  “Anecdotally we have heard of similar algae blooms in area waterways but Coal Creek is so visible that this one is causing a bit of a stir. We’ve never seen anything like this in Coal Creek and it seems to have really taken off since the end of August. We also plan to collect some aquatic insects in the creek and see how they are being impacted from this.”
Poponi said the algae may not be rock snot but he is waiting for final results of sample tests. As far as the fuel oil leak, authorities were called to the area by First Street and Sopris Avenue over Labor Day weekend. A marshal’s report states that on Sunday, September 5, a call was made about the leak. It turns out that an old fuel oil container that was used decades ago to hold fuel oil for a nearby house was leaking. It was buried but the leak went into the soil and into nearby Coal Creek.
Fire chief Ric Ems said the 500-gallon container was dug up and still had about 200 gallons of “product” in it. “The current property owner said she had bought the house in 1980 and had never known the container was even there,” he said. “There are probably a lot of those old buried fuel containers around town. That’s how people used to heat their homes.”
Due said the old fuel tanks and their ramifications are the responsibility of the homeowners and not the town. He said the Labor Day weekend leak did not pose any public health issues.
The fire department did place some absorbent socks in the creek to try to collect the fuel oil. Chief Ems said the fuel tank leak and the algae appear to be unrelated.
Billick said scientists at RMBL don’t understand why the algae seems to be exploding. “There’s a bunch of hypotheses on what’s going on but it is something we should be watching, and we are.”
They can now watch it in Coal Creek.