New record of moss and thermophilic bacteria species and physico-chemical properties of geothermal soils on the northwest slope of Mt. Melbourne (Antarctica) in 2002

Four samples of surface soils, one with shoots of an unidentified moss species,
were collected from a geothermal site on the northwest slope of volcanic Mt.
Melbourne (northwest Victoria Land, continental Antarctica) to determine
physico-chemical properties, isolate existing strains of etherotrophic
microorganisms, and identify the moss species through molecular genetic
techniques. Surface soils features such as temperatures, grain-size, pH,
moisture content and isolated genera of bacteria, generally corresponded to
those previously reported for other geothermal site in Victoria Land. However,
when compared with chemical characteristics of warm substrata from these sites,
soils from the northwest slope of Mt. Melbourne showed lower contents of total
N and water-extractable PO43- and K+ and relatively high concentrations of Na,
Fe, Mn and of potentially toxic elements such as Cd and Pb. Preliminary results
indicate that a new species of thermophilic bacteria growing in Fe-enriched
medium was isolated. Although the study area lay only about 1.5 km from
Cryptogam Ridge, a geothermal site in the rim of the Mt. Melbourne summit
crater with a well-developed population of the moss Campylopus pyriformis,
molecular genetic analysis showed that the moss of the volcano slope is Pholia
nutans, a species closely related to some populations 110 km to the north in
the Mt. Rittmann fumaroles. It was concluded that physico-chemical features of
geothermal grounds may affects the colonization history and dispersal of
microorganisms and mosses.