Role of Cyanobacteria in the Ecology of Polar Environments

Goethem, Marc W. Van; Cowan, Don A.

doi:10.1007/978-3-030-02786-5_1

Cited by 16 publications

(17 citation statements)

References 114 publications

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“…Heterocystous Cyanobacteria, predominantly Nostoc commune , appear to drive nitrogen fixation in Antarctic soils. Other heterocystous Cyanobacteria including Calothrix , Dichothrix , Nodularia and Hydrocoryne may play a role in sequestering nitrogen in soils and rock-associated niches such as hypoliths and endoliths [ 39 , 40 , 54 ]. Several studies have reported that nitrogen sequestration genes, linked to rate limiting steps in the cycle including ammonia oxidation, are homologous to those previously found in Cyanobacteria including Nitrosospira and Nitrosomonas [ 41 , 42 ].…”

Section: N-cycling Taxa In Soilsmentioning

confidence: 99%

“…These studies support the conclusion that the capacity for diazotrophy is widespread in nutrient-poor Antarctic soils, other than in certain high altitude edaphic areas [ 55 , 56 , 57 ]. However, the extent and importance of interactions among Antarctic taxa, and their importance in diazotrophy, is not well understood, although there is some evidence that cooperativity between Cyanobacteria and other taxa (e.g., Actinobacteria, Bacteroidetes and Proteobacteria) is essential for completion of the nitrogen cycle [ 34 , 40 , 58 ].…”

Section: N-cycling Taxa In Soilsmentioning

confidence: 99%

“…N-fixation : Diazotrophic members of microbial communities encoding the nitrogenase enzymatic complex are responsible for the biological fixation of atmospheric N 2 [ 78 ]. This key, high energy-cost and irreversible reaction involves the reduction of N 2 into NH 4 + by the canonical Mo-nitrogenase [ 40 , 79 ]. A functional and mature nitrogenase enzymatic complex can involve multiple genes encoded on different operons [ 79 , 80 ], with a minimal conserved core of six structural and cofactor biosynthetic genes [ 81 ].…”

Section: N-cycling Genes In Soilsmentioning

confidence: 99%

“…Most studies take advantage of the robustness of the nifH gene as a functional marker to identify diazotroph diversity in natural environments [ 86 ]. Across the Antarctic region, nifH gene analysis has been used to determine the abundance of autotrophic Cyanobacteria, particularly in cryptic soil habitats such as hypoliths and endoliths [ 34 , 36 , 40 , 68 ]. However, the presence of Cyanobacteria is not an absolute indicator of N-fixation as there are reported examples of loss of the nif H gene from their genomes [ 87 ].…”

Section: N-cycling Genes In Soilsmentioning

confidence: 99%

“…Microbial communities in Antarctic terrestrial habitats are thought to be primary ecosystem service providers through the input of nitrogen gas into the biosphere via nitrogen fixation into ammonia and subsequent nitrification [ 40 ]. This assumption is partly informed by the abundance of N 2 -fixing nitrifying microorganisms in both open soils and cryptic niches, such as diazotrophic Cyanobacteria and Proteobacteria [ 73 , 88 , 103 ], as well as ammonia oxidizing mosses that dominate several Antarctic landscapes [ 41 ].…”

Section: N-cycling In Antarctic Soils: Rates Processes and Ecosysmentioning

confidence: 99%

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Microbial Nitrogen Cycling in Antarctic Soils

et al. 2020

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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.

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