title: Hypolithic communities: important nitrogen sources in Antarctic desert soils.
abstract: Hypolithic microbial communities (i.e. cryptic microbial assemblages found on the undersides of translucent rocks) are major contributors of carbon input into the oligotrophic hyper-arid desert mineral soils of the Eastern Antarctic Dry Valleys. Here we demonstrate, for the first time, that hypolithic microbial communities possess both the genetic capacity for nitrogen fixation (i.e. the presence of nifH genes) and the ability to catalyse acetylene reduction, an accepted proxy for dinitrogen fixation. An estimate of the total contribution of these communities suggests that hypolithic communities are important contributors to fixed nitrogen budgets in Antarctic desert soils.
authors.affiliation: Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, Cape Town, South Africa. Wrigley Institute for Environmental Studies, University of Southern California, Los Angeles, CA, USA. Department of Biological Sciences, University of Waikato, Hamilton, New Zealand. College of Earth and Ocean Science, University of Delaware, Lewes, DE 19958, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Cowan
authors.forename: J A
authors.initials: JA
authors.lastname: Sohm
authors.forename: T P
authors.initials: TP
authors.lastname: Makhalanyane
authors.forename: D G
authors.initials: DG
authors.lastname: Capone
authors.forename: T G A
authors.initials: TG
authors.lastname: Green
authors.forename: S C
authors.initials: SC
authors.lastname: Cary
authors.forename: I M
authors.initials: IM
authors.lastname: Tuffin