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By
Peter Rejcek
Even mold is tougher in the Antarctic.
Microbiologists from the University of Minnesota are still
learning just how hardy several recently discovered species
of molds are as part of an effort to preserve historic
structures around the continent.
Principal Investigator Robert Blanchette and his team
at the Forest Pathology and Wood Microbiology Research
Laboratory have found that indigenous Antarctic fungi
have quite an appetite for wood introduced here by the
explorers and expeditions of the early 20th century.
Working with New Zealand’s Antarctic Heritage Trust,
Blanchette and his team are studying the molds, in part,
to understand what makes them thrive in order to stop
their advance at historic structures, particularly the
huts of Ross Island. (See the Feb. 5, 2006, issue of The
Antarctic Sun at antarcticsun.usap.gov)
“These organisms tend to be found in extreme environments
… in areas that exclude other organisms,” explained
Blanchette during a phone interview from his office at
the university.
One of his graduate students, Brett Arenz, embarked on
a special mission in January to remote Stonington Island
in the Antarctic Peninsula area. The island is home to
East Base, the oldest extant U.S. Antarctic station. Built
in 1940, East Base was only used for a couple of seasons,
including the privately funded Ronne Antarctic Research
Expedition of 1947-48. This was the first expedition to
include women to winter over on the continent.
Three East Base structures still remain, according to
Arenz, and include a bunkroom, laboratory and a building
used by the base commander. The site is designated as
Historic Site and Monument No. 55 under the Antarctic
Treaty system.
Arenz joined a conservation team with the British Antarctic
Survey (BAS), the United Kingdom’s counterpart to
the U.S. Antarctic Program. He traveled aboard the HMS
Endurance, a British Royal Navy research vessel, to assess
the microbes at East Base. He also worked alongside the
BAS conservators at a number of historic British structures,
including Base E, located a couple hundred meters from
the American structures and also designated as a historic
site and monument.
“It’s really a collaborative effort [with BAS],”
Arenz said shortly before the five-week cruise.
Based on their work on Ross Island and sites around Palmer
Station, the scientists say the same handful of mold species
are likely attacking the wooden structures at East Base,
perhaps with even more gusto thanks to the climatic ambience
that the molds prefer when they dine.
“Since it is warmer and more humid there, there should
actually be more microbial deterioration of the wood,”
Arenz explained, “because the environmental conditions
should be more conducive to that, but no one has investigated
that up until now.”
The last report on the condition of the structures at
Stonington Island date back to 1992, according to Blanchette.
Some activity took place then to fortify the buildings
against the elements.
“In the 15 years since then, there has apparently
been some extensive deterioration that has occurred,”
Arenz said, based on information from one of the BAS conservators.
“Hopefully, I’ll be able to document that in
more detail using photos and videos so they’ll be
able to make a plan about more [conservation] work that
needs to be done.”
Added Blanchette, “We have great interest, of course,
in historic preservation with the work that we’re
doing with the historic huts in the Ross Sea region, especially
on Ross Island.”
Scientists do not know much about Antarctic fungi at this
point. It appears they live in the nutrient-poor Antarctic
soils, feeding on what organic material they can find
such as dead lichen, moss or penguin carcasses. The introduction
of wood by early expeditions offered the molds something
of an all-you-can-eat buffet.
“They started to colonize it and use it,” Blanchette
said.
The molds cause an unusual decay that the scientists call
a “soft rot,” penetrating the cell walls of
the wood and other materials in the historic buildings
such as textiles. They then grow inside the cells, protected
from toxic substances, such as salt, that would normally
kill them. Similar species are found in the Arctic as
well as hot, dry desert regions.
“They seem to be especially well suited for survival
in the extremes,” Blanchette noted. “They appear
to be circumpolar in their distribution.”
At the Ross Island huts, the molds become active during
the brief summer season, perhaps for only a couple months,
and then remain dormant through much of the year. Moisture
created by ice melting on the outside of the huts increases
the fungal blooms. That’s particularly true at Cape
Evans, where preservation work involves removing the ice
and snow from around the hut and drying out the building
as much as possible.
“There’s a lot to do at Cape Evans,” Blanchette
conceded.
While conservationists may view these particular fungi
as pests, they do play an important role in the Antarctic
ecosystem for decomposing organic material, according
to Blanchette. To better understand those processes, the
team runs several biodiversity studies on Ross Island
and around Palmer Station on the Antarctic Peninsula.
The researchers buried sterile wood, cotton and similar
materials to see how the microbes in the soil would react.
Any microbes found on the material has to have been since
they were buried in the soil, Arenz said. “We’ve
found very high concentrations of the same kind of fungi
that we’ve found in the huts, indicating that these
organisms are in the soils.”
The studies should help the microbiologists learn more
about the organisms’ growth, behavior and survival
strategies.
“We’re just trying to find out what these unusual
microbes are and learn more about their biology and ecology
in the polar environment,” Blanchette said.
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Antarctic
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