Microbial Nitrogen Cycling in Antarctic Soils

The Antarctic continent is widely considered to be one of the most hostile biological habitats on Earth. Despite extreme environmental conditions, the ice-free areas of the continent, which constitute some 0.44% of the total continental land area, harbour substantial and diverse communities of macro...

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Bibliographic Details
Published in:Microorganisms
Main Authors: Max Ortiz, Jason Bosch, Clément Coclet, Jenny Johnson, Pedro Lebre, Adeola Salawu-Rotimi, Surendra Vikram, Thulani Makhalanyane, Don Cowan
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2020
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Online Access:https://doi.org/10.3390/microorganisms8091442
https://doaj.org/article/8f2fde91aeac457283e1efbd607414f6
Description
Summary:The Antarctic continent is widely considered to be one of the most hostile biological habitats on Earth. Despite extreme environmental conditions, the ice-free areas of the continent, which constitute some 0.44% of the total continental land area, harbour substantial and diverse communities of macro-organisms and especially microorganisms, particularly in the more “hospitable” maritime regions. In the more extreme non-maritime regions, exemplified by the McMurdo Dry Valleys of South Victoria Land, nutrient cycling and ecosystem servicing processes in soils are largely driven by microbial communities. Nitrogen turnover is a cornerstone of ecosystem servicing. In Antarctic continental soils, specifically those lacking macrophytes, cold-active free-living diazotrophic microorganisms, particularly Cyanobacteria, are keystone taxa. The diazotrophs are complemented by heterotrophic bacterial and archaeal taxa which show the genetic capacity to perform elements of the entire N cycle, including nitrification processes such as the anammox reaction. Here, we review the current literature on nitrogen cycling genes, taxa, processes and rates from studies of Antarctic soils. In particular, we highlight the current gaps in our knowledge of the scale and contribution of these processes in south polar soils as critical data to underpin viable predictions of how such processes may alter under the impacts of future climate change.