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Scientists tackle Antarctic mold
Study contributes to effort to restore historic buildings around the continent
Posted February 4, 2007
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.”
Certain molds, such as this growing on a boot in the historic hut at Cape Evans, seem to thrive even in the harsh environment of Antarctica.
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.
NSF-funded research in this story: Robert Blanchette, University of Minnesota.