Wood-Destroying Soft Rot Fungi in the Historic Expedition Huts of Antarctica

Abstract

Three expedition huts in the Ross Sea region of Antarctica, built between 1901 and 1911 by Robert F. Scott and Ernest Shackleton, sheltered and stored the supplies for up to 48 men for 3 years during their explorations and scientific investigation in the South Pole region. The huts, built with wood taken to Antarctica by the early explorers, have deteriorated over the past decades. Although Antarctica has one of the coldest and driest environments on earth, microbes have colonized the wood and limited decay has occurred. Some wood in contact with the ground contained distinct microscopic cavities within secondary cell walls caused by soft rot fungi. Cadophora spp. could be cultured from decayed wood and other woods sampled from the huts and artifacts and were commonly associated with the soft rot attack. By using internal transcribed spacer sequences of ribosomal DNA and morphological characteristics, several species of Cadophora were identified, including C. malorum, C. luteo-olivacea, and C. fastigiata. Several previously undescribed Cadophora spp. also were found. At the Cape Evans and Cape Royds huts, Cadophora spp. commonly were isolated from wood in contact with the ground but were not always associated with soft rot decay. Pure cultures of Cadophora used in laboratory decay studies caused dark staining of all woods tested and extensive soft rot in Betula and Populus wood. The presence of Cadophora species, but only limited decay, suggests there is no immediate threat to the structural integrity of the huts. These fungi, however, are widely found in wood from the historic huts and have the capacity to cause extensive soft rot if conditions that are more conducive to decay become common.

Living strategy of cold-adapted fungi with the reference to several representative species

“…In general, the fungal communities of Antarctic soils are dominated by filamentous ascomycetes and basidiomycete yeasts (Connell et al 2008; Arenz and Blanchette 2011). Filamentous basidiomycetes that are typically known as wood-decay fungi in temperate ecosystems have been very rarely isolated in Antarctica (Blanchette et al 2004; Ludley and Robinson 2008). Fungi in Zygomycetes are also isolated with some frequency in Antarctic (Lawley et al 2004).…”

“…A group of cold-adapted fungi decompose woody structures and artefacts left by the early polar explorers in Antarctic. Blanchette et al (2004) first reported an unusual form of soft rot decay caused by Cadophora species which can cause degradation of the historic huts and artefacts. This type of decay has subsequently been found to be prevalent in historic woods and in soils from the immediate vicinity of the huts at many Antarctic locations and variety of filamentous fungi and yeasts such as Cadophora, Cladosporium, Cryptococcus and Geomyces species were discovered with a high frequency (Arenz et al 2006; Arenz and Blanchette 2009; Blanchette et al 2010).…”

“…This type of decay has subsequently been found to be prevalent in historic woods and in soils from the immediate vicinity of the huts at many Antarctic locations and variety of filamentous fungi and yeasts such as Cadophora, Cladosporium, Cryptococcus and Geomyces species were discovered with a high frequency (Arenz et al 2006; Arenz and Blanchette 2009; Blanchette et al 2010). Although there are few woody plants on the Antarctic continent, researches provide strong evidence that Antarctic fungi are able to colonise and degrade-introduced wood and other organic materials (Blanchette et al 2004, 2010). Held et al (2005) found that Antarctic summer above 0°C and 75% relative humidity occurred for many weeks, which are conducive for fungal growing inside the historic huts on Ross Island.…”

Timber transported to Antarctica: a potential and undesirable carrier for alien fungi and insects

“…Moreover, only soft rot fungi has been observed in the decomposition of wooden structures, mostly old huts, in Antarctica (Blanchette et al 2004) and it was concluded that the harsh climate conditions preclude the development of white and brown rot fungi. This would exclude all wood decomposing Basidiomycota from the biota of Antarctica.…”

Diversity of microfungi in ornithogenic soils from Beaufort Island, continental Antarctic

“…Studies have taken place both in relatively easily accessible and more benign locations (Azmi et Seppelt 1990, Cheryl et Seppelt 1999 and in more environmentally challenging areas such as the Victoria Land Dry Valleys (Friedmann et al 1985, Cameron et al 1971. The occurrence of fungi associated with humanassociated habitats and artifacts, such as in historical huts, have been studied extensively by Tubaki (1961), Martin (1988), Blanchette (2000), Blanchette et al (2004) and Held et al (2005).…”