Rivers in the South Island of New Zealand are absolutely infested with didymo
'Rock
Snot' Infestation Caused by Climate Change, Study Suggests
A
didymo mat several centimeters thick covers the rocky substrate of
the crystal clear Duval River. …
5 March, 2014
A pesky species of algae — sometimes called "rock snot" due to the way its tendrils attach to rocks in waterways — is infiltrating parts of eastern Canada due to global warming and not accidental introductions from humans tromping around, a new study suggests.
One lake studied in the Gaspésie region of Quebec showed fossilized Didymosphenia geminata (one species of didymo) dating back to about 1970, or 36 years before the first official reports of an outbreak were recorded in the region.
Another lake, which has inflowing river sediments and does not contain evidence of didymo, showed an increase in other algae species at about the same rate that didymo proliferated in the first lake. The increase in algae was consistent with patterns associated with climate change, the researchers who examined the lakes said.
"We can't make any solid claims as to what the mechanism is that is favoring didymo, but we strongly suspect it has to do with climate," said study leader Michelle Lavery, a graduate student at the University of New Brunswick. [10 Surprising Results of Global Warming]
Washing waders
Lavery
performed the research at Queen's University in Ontario under the
supervision of John Smol and his postdoctoral researcher Joshua
Kurek, an avid fly fisherman who always heeded the advice to "wash
his waders" to stop the transport of this algae from waterway
to waterway.
As
an ecologist, however, Kurek knew that diatoms (single-celled algae)
typically are present in many ecosystemsbecause
they're easily transported by the wind between different lakes. "If
there's a bucket of water on the roof left overnight, it will be
colonized by diatoms," Lavery told Live Science.
To
see if the species was, indeed, invasive, Kurek recruited Lavery to
help him check out the environment in two Quebec lakes: Lac au
Saumon (a didymo-infested lake with a strong current running into
it) and Lac Humqui, a headwater lake with no inflowing rivers.
When
taking a sample core from Lac au Saumon's bottom sediments,
researchers found remains of didymo all the way down to the bottom
layers, from about 1970. Lac Humqui, although free of didymo, had
"this really striking pattern of algal community change"
that correlated well with the increasing didymo concentrations found
in the Lac au Saumon core, Lavery said.
The
researchers also examined archival diatom surveys and found explicit
mentions of the species dating back to at least 1910, with more
oblique references to it dating back to 1896.
Researchers
had been "operating under the assumption it's invasive, and
it's guiding our research," Lavery said. "These are
important steps to redirect our efforts." Although the
researchers don't believe that didymos are invasive species, Lavery
added it is good practice anyway to wash equipment between waterways
to prevent human transport of other lifeforms.
Little
is known about where didymo tend to colonize, but generally, the
species prefers to grow in fast-flowing waters that don't experience
a lot of disruption from ice melts every spring. In warmer
climates,
the ice melts are slower and less severe, making it easier for
didymo mats to persist from season to season — suggesting that
warming may be behind the recent proliferation of didymo in these
parts of Canada.
While
Lavery's research now focuses on Atlantic salmon, she said Kurek
plans to expand on the didymo research and is now talking with other
didymo researchers in Canada and the United States.
The
study was published in the Canadian Journal of Fisheries and Aquatic
Sciences and includes participation from Queen's University, Brock
University in Ontario, and Quebec's National Institute of Scientific
Research.
Follow
Elizabeth Howell @howellspace,
or LiveScience on Twitter @livescience.
We're also on Facebook &Google+.
No comments:
Post a Comment
Note: only a member of this blog may post a comment.