Rock snot has been in the news.
It is a simple organism. Its proper name is Didymosphenia germinata but many researchers in the field refer to it as didymo.
It is a species of algae and specifically, it is a diatom. This means it has cell walls composed of silicates, which often leads to interesting and complex shapes.
In the case of rock snot, it is a simple cylindrical single-celled creature. It grows in waters with low nutrient levels and cold temperatures. All in all, it is a rather unassuming organism except for the fact that it looks like and has the consistency of, well, snot.
Part of the reason that it was in the news this past week is a paper on rock snot, published by Max Bothwell of Environment Canada and Brad Taylor of Dartmouth, featured prominently in reports on the recent muzzling of federal scientists by the Conservative government.
When their paper first appeared, several journalists attempted to interview Bothwell.
He has been described by his co-author as the "Yoda of knowledge about didymo" and is well recognized internationally as a leading scientist in the field.
However, as Dene Moore of the Canadian Press tells it, Environment Canada put up roadblocks and stonewalled for several weeks. A freedom of information request generated over 110 pages of emails discussing her request for an interview including comments such as "CP asked to interview Max today but media relations is negotiating that to buy us more time."
Fortunately, Moore was able to get an interview with Taylor in a matter of hours so she was still able to report on the paper and its results. And with the change in government in Canada, Bothwell is now free to discuss his findings with the press.
What is it about this organism - a simple, unassuming single celled creature - that caused such a ruckus? As you might suspect, there is a link to climate change.
Or, at least, there is the possibility of a link to climate change but that is not the only issue. The bigger question for biologists was to determine if didymo is an invasive species or a naturally occurring part of the ecosystem. The whole question of invasive species has been and continues to be a hot topic in biology.
The most recent data indicates the alga is naturally present in all of the waterways it presently inhabits. It is a native species and not introduced into water around the globe by human interactions, with the possible exception of New Zealand.
That finding has implications for the increased abundance of didymo. Blooms carpeting river beds and rocks have been found in Canadian rivers over the past 30 years or so. Indeed, my first encounter with rock snot was in the early 1980s on Vancouver Island as we were exploring caves. It is now prevalent throughout the province.
The most likely explanation is that with didymo present naturally, the blooms are a consequence of changing environmental conditions. Read: climate change.
Changes in ice cover and nutrient deficiencies might lead to conditions where the alga thrives. In particular, Bothwell and Taylor attributed the rampant increase to decreased levels of phosphorus in waterways. Organisms that grow in low-nutrient conditions are historically rare species but being adapted to such conditions give these creatures a tremendous evolutionary advantage.
Biologists have documented shifts from larger to smaller fish species present in streams containing didymo blooms. The presence of the algae appears to alter the food web and is consequently a threat to salmon and trout. However, changes in the food web might also arise from the low-nutrient conditions and a didymo bloom might be more of a response or symptom than a cause.
Presently, strategies to control the perceived spread of the organism have focused on trying to prevent cross contamination.
Signs warning boaters of the presence of didymo and the need to thoroughly clean their boats have appeared by many streams and rivers.
Conservation efforts have been engaged in pristine waterways.
Bothwell and Taylor argued mitigating the environmental factors is more likely the correct approach. As Taylor put it: "Correctly identifying an invasive species as either native or non-native is important for developing sound policy, management, and scientific research programs because effective responses depend on knowing whether the species' dominances is cause by ecological or evolutionary novelty, changes in environmental conditions that facilitate it, or both."
In other words, if fisheries management doesn't understand that didymo is present in all water, they will not adopt an appropriate strategy for managing the blooms.
Indeed, using chemicals as a method to destroy the organism might have unintended consequences leading to lower nutrient levels and increased blooms.
It would appear that as long as our climate keeps shifting, we are going to see more rock snot in our streams and rivers.
