A strange green organism has spread around the globe, clogging up the world's rivers
Presented by Larry O'Hanlon
Has Didymo always been in the rivers of British Columbia?
It
began with a few small strange patches of slime, clinging to the rocks
of the Heber River in Canada. Within a year, the patches had become
thick, blooming
mats. Within a few years the mats had grown into a giant green snot.
And within a few decades this snot had spread around the world, clogging
up rivers as far away as South America, Europe and Australasia.
This snot, which is still flourishing today, is caused by a microscopic alga, a diatom that goes by its scientific name
Didymosphenia geminata. It has become so notorious it has its own
moniker, Didymo. People have been blamed for the sudden, global
explosion of this tiny organism, unwittingly carrying the algae from
river to river on fishing gear, boats and kayaks. The
huge snots it forms have wreaked havoc in waterways, forcing
governments and environmental organisations to initiate huge and costly
clean-up operations.
But
underlying the snots’ strange appearance is an even stranger story.
About Didymo itself, about what it is, and how it behaves.
Scientists are now discovering that the sudden appearance of Didymo may not have been so sudden after all.
River users are told to help stop Didymo.
Its
blooms aren’t really blooms – instead they are more of an
elixir-induced metamorphosis. And Didymo seems to ignore the usual rules
followed by invasive
species. It even appears likely that this little diatom may not even be
a significant problem itself; instead the green snot it forms may be a
symptom of greater changes underway in freshwater systems around the
world.
