Forty years is a long time for something to survive in nature. but that's how long it is said that didymo - also known as "rock snot" - can survive outside a stream in a cool, dark environment.
An alert has been issued to anglers and boaters all across the state, regardless of whether they use affected waters: Clean your gear.
Didymo, an invasive, aquatic plant, recently was found on a portion of Pine Creek in Lycoming County by the state Department of Environmental Protection.
It is likely didymo came to the Pine Creek by clinging to the equipment and gear of anglers, kayakers and canoers.
The hope, at this point, is that it doesn't spread more - because it only takes one cell and it's off. Didymo could have a tremendously negative effect on the wildlife living and thriving in the water system.
What is it
Didymosphenia geminata, also known didymo, is a microscopic algae called a diatom.
"It has the characteristics of an invasive species, forming massive blooms that blanket streambeds, clog streams and rivers, and threaten aquatic ecosystems," said Rachel Wagoner, resources management specialist with the Bureau of State Parks division of the state Department of Conservation and Natural Resources.
It wasn't until the 1980s that didymo was found in colder, alpine lakes in northern Europe and North America.
It now is found in the east and west branches of the Delaware River, the Youghiogheny River and, now, Pine Creek.
Staff from DCNR and the state Department of Environmental Protection were doing routine water sampling in June when the algae was found in the vicinity of the Hamilton Beach Bottom Canoe Access Area on Pine Creek.
"They were looking specifically for diatoms and identified the infestation in Pine Creek by observing just a few cells," Wagoner said. "Imagine the odds of finding it not by observing large, waving mats attached to the rocks on the stream bottom, but by seeing just one or two cells under a microscope. The large mats have since been seen in the creek, but that wasn't the initial find."
Thick clogging mats
Didymo grows in dense colonies or blooms that elongate into stalks.
"The extracellular stalk material forms thick mats that appear as strands of toilet paper or fiberglass," Wagoner said.
It is different than algae some see covering a typical stagnant pond.
"It feels more like wet wool socks or a wet cottonball when you touch it," she said. "Another difference is didymo is found in moving water - not in lakes or ponds - and is generally brown, tan or pale yellow in color, never green."
The plant attaches itself to both stones and plants and, Wagoner said, research indicates that didymo prefers shallow and clear, moderately flowing streams and rivers with rocky substrates and low nutrients.
"But 'rock snot' doesn't read the research," she said. "It is exhibiting a much greater tolerance for nutrients and flow conditions."
This makes Pine Creek its perfect victim.
Once a stream is infested with it, the algae always is there.
Wagoner said the blooms sometimes are more apparent from year to year or even season to season.
The water and wildlife can be tremendously affected during one of the didymo's nuisance blooms.
"Didymo cells create large amounts of stalk material that form thick mats on the bottom of rivers and streams. These mats are capable of engulfing a stream bottom and smothering native species of plants, insects and mollusks. This reduces habitat and food availability for aquatic insects and fish," Wagoner said.
A major impact could be felt among fisheries, tourism and hydropower, she added,
"In Pennsylvania, didymo has the potential to impact trout fisheries by altering the aquatic invertebrate food base, as well as altering water quality parameters that could be harmful to trout ... not to mention the inconvenience of having to spend minutes picking bits of 'snot' off a fly between each cast," Wagoner added.
Combat by cleaning
There always is a risk of spreading didymo even if it can't be seen.
An effort is being made to alert all those who use waterways.
"As far as getting rid of didymo, once it's in a waterway, there aren't any practical ways of going in after the fact and cleaning it up. It would be impossible to physically scrape all of it off rocks, and using a chemical solution of some kind poses harm to all the other aquatic life," said Eric Levis, press secretary with the state Fish and Boat Commission.
Right now, the best thing the agency can do is repeatedly tell anglers and boaters to clean their gear to help it from spreading, he said.
"The northcentral region of Pennsylvania is home to many exceptional fishing and boating opportunities. Many will visit more than one stream in the course of the day or over a weekend. An unfortunate likelihood is didymo may have been moved as well," Wagoner said.
With no known effective ways to control didymo, Wagoner said, there are no suppression plans in the works.
"DCNR will continue to educate visitors about the threats to the stream ecosystem and encourage recreationers to clean their gear to reduce the spread to other waterways," she said.
As gross as rock snot sounds, the plant poses no threat to humans, Wagoner said.