“Rock Snot” yucky, also threatens Nova Scotian streambeds
by Sadie Beaton
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| Illustration by Sydney Smith |
If you’re eight years old at heart, you might giggle at the mention of “rock snot.” But if you are an angler or biologist, you are more likely swearing under your breath. “Rock snot” is the apt nickname given by anglers for a species of single-celled algae known more formally as didymo. Defined by a large, gooey silica encasement, these invasive organisms are arriving by the millions, from New Zealand to New England.
Rock snot arrives on the scene as a warty brown bubble, and as it develops, takes on the appearance of matted, dirty clumps of wool. Soon, the bloom transforms cool, clear freshwater streams into sticky brown slime. By the end of its life cycle, these organisms grow long white stalks that break down and float downstream in clumps that are often mistaken for soiled toilet paper.
Gross, definitely, but rock snot is also alarming, because there are indications that this repulsive algae has begun to invade Nova Scotia rivers. While didymo is not harmful to humans, except as a minor eye irritant, its presence can threaten fish populations. By blanketing stream bottoms, it smothers food sources for insects and fish, including our fragile salmon populations.
The current spate of aggressive didymo blooms around the world is a bit of a mystery. Scientists point in various directions, from ozone depletion, to a proliferation of dams, to the removal of shade that results from some forestry practices. Many also see a slime trail being left behind by globetrotting anglers, starting around the time that felt-bottomed boots were introduced.
Campaigns to contain didymo aimed at stream users have been launched in many regions, following the formula of “check, clean and dry.” This regime calls for careful inspection and disinfection of all equipment between visits to different streams. So don’t forget to clean your boots, swim trunks, boats, and/ or pets, as it only takes one cell to spread these nasty boulder boogers to a new stream.
Sadie Beaton coordinates the Coastlines monthly natural history column and will be celebrating the International Day for Biological Diversity on May 22nd. This year’s theme is invasive alien species, one of the greatest threats to the ecological and economic well-being of society and the planet. Coastlines is coordinated by the Coastal Issues Committee at Ecology Action Centre and supported by the Nova Scotia Habitat Conservation Fund with contributions from hunters and trappers.
Coastal Issues Committee
Phone: (902) 442-5046
Fax: (902) 405-3716
How do you like your coast? Take action on coastal issues that matter to you. The Coastal Issues Committee meets at the EAC on the last Thursday of every month at 5:30PM.
