scholarly journals Microbial Nitrogen Cycling in Antarctic Soils

2020 ◽  
Vol 8 (9) ◽  
pp. 1442 ◽  
Author(s):  
Max Ortiz ◽  
Jason Bosch ◽  
Clément Coclet ◽  
Jenny Johnson ◽  
Pedro Lebre ◽  
...  
Keyword(s):  
Nitrogen Cycling ◽  
Future Climate Change ◽  
Dry Valleys ◽  
Antarctic Soils ◽  
Critical Data ◽  
Microbial Nitrogen ◽  
Victoria Land ◽  
Cold Active ◽  
Antarctic Continent ◽  
The Antarctic

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.

scholarly journals Biogeography of terrestrial cyanobacteria from Antarctic ice-free areas

2010 ◽  
Vol 51 (56) ◽  
pp. 171-177 ◽  
Author(s):  
Z. Namsaraev ◽  
M.-J. Mano ◽  
R. Fernandez ◽  
Annick Wilmotte
Keyword(s):  
Rrna Gene ◽  
Distribution Analysis ◽  
Operational Taxonomic Units ◽  
Terrestrial Cyanobacteria ◽  
Victoria Land ◽  
Low Degree ◽  
Range Transport ◽  
Antarctic Continent ◽  
The Antarctic ◽  
Further Development

AbstractCyanobacteria inhabit the Antarctic continent and have even been observed in the most southerly ice-free areas of Antarctica (86–87° S). The highest molecular diversity of cyanobacterial communities was found in the areas located between 70° S and 80° S. Further south and further north from this zone, the diversity abruptly decreased. Seventy-nine per cent (33 of 42 operational taxonomic units) of Antarctic terrestrial cyanobacteria have a cosmopolitan distribution. Analysis of the sampling efforts shows that only three regions (southern Victoria Land, the Sør Rondane Mountains and Alexander Island) have been particularly well studied, while other areas did not receive enough attention. Although cyanobacteria possess a capacity for long-range transport, regional populations in Antarctic ice-free areas seem to exist. The cyanobacterial communities of the three most intensively studied regions, separated from each other by a distance of 3000–3400 km, had a low degree of similarity with each other. Further development of microbial biogeography demands a standardized approach. For this purpose, as a minimal standard, we suggest using the sequence of cyanobacterial 16S rRNA gene between Escherichia coli positions 405 and 780.

Diversity and distribution of tardigrades in soils of Edmonson Point (Northern Victoria Land, continental Antarctica)

2012 ◽  
Vol 2 (2) ◽  
pp. 61-70 ◽  
Author(s):  
Jerzy Smykla ◽  
Nataliia Iakovenko ◽  
Miloslav Devetter ◽  
Łukasz Kaczmarek
Keyword(s):  
Water Content ◽  
Austral Summer ◽  
High Water ◽  
Soil Samples ◽  
High Water Content ◽  
Strong Constraint ◽  
Antarctic Soils ◽  
Victoria Land ◽  
Continental Antarctica ◽  
The Antarctic

This work contributes to the knowledge on distribution, diversity and ecology of the Antarctic soil biota. Different soil habitats from several ice-free coastal sites were sampled along the Victoria Land across 7° of latitude from 71° to 78°S during five austral summer seasons between 2003/04 and 2011/12. In this paper we report preliminary data on soil tardigrades (water bears) from Edmondson Point, Northern Victoria Land. Tardigrades were found to be present in 23 of the 41 examined soil samples (56%). Their presence was associated exclusively with soil samples collected from bryophytes communities and under cyanobacterial mats, whereas they were completely absent in fellfield and ornithogenic soils. Tardigrades were least numerous among all soil micrometazoans, their abundance in the positive samples was very variable and ranged from 3 to 1824 individuals per 100 g of soil DW. High water content seemed to be the major factor determining occurrence of tardigrades in the soils investigated. On the other hand low water content and toxic compounds from penguin guano seemed to act as a strong constraint on their existence in the Antarctic soils. Taxonomic evaluation of the extracted tardigrades revealed presence of only two species belonging to class Eutardigrada: Acutuncus antarcticus (Richters, 1904) and Milnesium antarcticum Tumanov, 2006. While A. antarcticus has already been reported previously as the most widespread and abundant tardigrade across the Victoria Land, the information on M. antarcticum is novel, both for Victoria Land and the continental Antarctica.

scholarly journals Insights on the environmental impacts associated with visible disturbance of ice-free ground in Antarctica

2019 ◽  
Vol 31 (6) ◽  
pp. 304-314 ◽  
Author(s):  
Shaun T. Brooks ◽  
Pablo Tejedo ◽  
Tanya A. O'Neill
Keyword(s):  
Human Activity ◽  
Native Species ◽  
Visual Analysis ◽  
Heavy Metal Contamination ◽  
Dry Valleys ◽  
Environmental Consequences ◽  
Species Establishment ◽  
Antarctic Continent ◽  
Terrestrial Biodiversity ◽  
The Antarctic

AbstractThe small ice-free areas of Antarctica provide an essential habitat for most evident terrestrial biodiversity, as well as being disproportionately targeted by human activity. Visual detection of disturbance within these environments has become a useful tool for measuring areas affected by human impact, but questions remain as to what environmental consequences such disturbance actually has. To answer such questions, several factors must be considered, including the climate and biotic and abiotic characteristics. Although a body of research has established the consequences of disturbance at given locations, this paper was conceived in order to assess whether their findings could be generalized as a statement across the Antarctic continent. From a review of 31 studies within the Maritime Antarctic, Continental Antarctic and McMurdo Dry Valleys regions, we found that 83% confirmed impacts in areas of visible disturbance. Disturbance was found to modify the physical environment, consequently reducing habitat suitability as well as directly damaging biota. Visible disturbance was also associated with hydrocarbon and heavy metal contamination and non-native species establishment, reflecting the pressures from human activity in these sites. The results add significance to existing footprint measurements based on visual analysis, should aid on-the-ground appreciation of probable impacts in sites of disturbance and benefit environmental assessment processes.

Twenty-seventh Antarctic Treaty Consultative Meeting Cape Town, South Africa, 24 May–4 June 2004

Polar Record ◽  
2005 ◽  
Vol 41 (1) ◽  
pp. 77-96 ◽  
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Management Plan ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Victoria Land ◽  
Antarctic Treaty ◽  
The Antarctic

The texts of the Decisions and Resolutions, and the text of Measure 1 (2004), together with a summary of the Management Plan for Antarctic Specially Managed area No. 2, McMurdo Dry Valleys, Southern Victoria Land, adopted at XXVII ATCM were reproduced in SCAR Bulletin No 155, October 2004. A summary of the Management Plan for Antarctic Specially Managed Area No. 3, Cape Denison, Commonwealth Bay, George V land, together with Measures 2–4, are reproduced here. The full versions of all the Decisions, Measures and Resolutions are on the Antarctic Treaty Secretariat website at http://www.ats.org.ar/

scholarly journals Antarctic Rahnella inusitata: A Producer of Cold-Stable β-Galactosidase Enzymes

2021 ◽  
Vol 22 (8) ◽  
pp. 4144
Author(s):  
Kattia Núñez-Montero ◽  
Rodrigo Salazar ◽  
Andrés Santos ◽  
Olman Gómez-Espinoza ◽  
Scandar Farah ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Galactosidase Activity ◽  
Bacterial Strains ◽  
Cold Active ◽  
Antarctic Continent ◽  
Physical And Chemical ◽  
The Antarctic ◽  
And Chemical Properties

There has been a recent increase in the exploration of cold-active β-galactosidases, as it offers new alternatives for the dairy industry, mainly in response to the current needs of lactose-intolerant consumers. Since extremophilic microbial compounds might have unique physical and chemical properties, this research aimed to study the capacity of Antarctic bacterial strains to produce cold-active β-galactosidases. A screening revealed 81 out of 304 strains with β-galactosidase activity. The strain Se8.10.12 showed the highest enzymatic activity. Morphological, biochemical, and molecular characterization based on whole-genome sequencing confirmed it as the first Rahnella inusitata isolate from the Antarctic, which retained 41–62% of its β-galactosidase activity in the cold (4 °C–15 °C). Three β-galactosidases genes were found in the R. inusitata genome, which belong to the glycoside hydrolase families GH2 (LacZ and EbgA) and GH42 (BglY). Based on molecular docking, some of these enzymes exhibited higher lactose predicted affinity than the commercial control enzyme from Aspergillus oryzae. Hence, this work reports a new Rahnella inusitata strain from the Antarctic continent as a prominent cold-active β-galactosidase producer.

Two new species of Eutardigrada from Victoria Land, Antarctica

Zootaxa ◽  
2017 ◽  
Vol 4317 (3) ◽  
pp. 541 ◽  
Author(s):  
GIOVANNI PILATO ◽  
GIORGIO SABELLA ◽  
VERA D’URSO ◽  
OSCAR LISI
Keyword(s):  
New Species ◽  
Distal Portion ◽  
Pharyngeal Bulb ◽  
Victoria Land ◽  
Basal Thickening ◽  
Two New Species ◽  
Pharyngeal Apparatus ◽  
Basal Portion ◽  
Antarctic Continent ◽  
The Antarctic

Two new species are recorded from Victoria Land (Antarctica): Mixibius felix sp. nov. and Milnesium validum sp. nov. A third species, Diphascon sanae Dastych, Ryan & Watkins, 1990, is a new report for this region of the Antarctic continent. Mixibius felix sp. nov. has a smooth cuticle, eyes present, bucco-pharyngeal apparatus of the Mixibius type (rigid buccal tube without ventral lamina and with hook-shaped asymmetrical apophyses for the insertion of the stylet muscles); stylet supports inserted on the buccal tube at 65.7–68.0% of its length; pharyngeal bulb with apophyses and two macroplacoids; microplacoid and septulum absent; as is characteristic of the genus, the external claws are of Isohypsibius type and the internal are a modified Isohypsibius type. Milnesium validum sp. nov. has smooth cuticle; eye spots present; six triangular peribuccal lamellae with basal stripes; stylet supports inserted on the cylindrical buccal tube at 61.1–64.8% of its length; claw configuration [3-3]-[3-3] (i.e. all secondary claws with three points); secondary claws stout, with distal portion clearly wider than the basal portion and each with a rounded basal thickening (lunule); primary claws with accessory points; a long cuticular bar present under claws I–III. Adding the three above mentioned species, the list of species present in Victoria Land rises from 12 to 15; 11 of these are recorded exclusively to this region of the Antarctic continent. 

The genus Luticola D.G.Mann (Bacillariophyta) from the McMurdo Sound Region, Antarctica, with the description of four new species

Phytotaxa ◽  
2015 ◽  
Vol 208 (2) ◽  
pp. 103 ◽  
Author(s):  
Tyler J Kohler ◽  
KATEŘINA KOPALOVÁ ◽  
BART VAN DE VIJVER ◽  
J. PATRICK KOCIOLEK
Keyword(s):  
New Species ◽  
New Combination ◽  
Dry Valleys ◽  
Electron Microscopic ◽  
Mcmurdo Sound ◽  
Scanning Electron Microscopic ◽  
Diatom Genus ◽  
Antarctic Continent ◽  
The Antarctic ◽  
Freshwater Diatom

A revision of the freshwater diatom genus Luticola from the McMurdo Sound Region, including the McMurdo Dry Valleys and Cape Royds, Antarctica, was made to contribute to a consistent flora for the entire Antarctic Region. Detailed light and scanning electron microscopic observations, review of pertinent literature, and examination of historical and type material lead to the identification of 12 Luticola species. Four new species and one new combination are proposed, including L. bradyi sp. nov., L. spainiae, sp. nov., L. macknightiae, sp. nov., L. transantarctica, sp. nov., and L. elegans, comb. nov. stat. nov. Several of these taxa were previously identified as part of the L. muticopsis (Van Heurck) D.G.Mann complex; Navicula muticopsis f. evoluta W. & G.S. West, L. muticopsis f. reducta (W. & G.S. West) Spaulding, and N. muticopsis f. capitata Carlson, or mistaken for the similar L. mutica (Kützing) D.G.Mann and L. cohnii (Hilse) D.G.Mann. Morphological features of all new species were compared to the closest morphologically similar taxa, and their ecology and biogeography are discussed. All Luticola species considered here show restricted Antarctic distributions, and 8 of the 12 reported species are known only from the Antarctic continent.

Lichens of the Oasis Molodyozhnyi and adjacent areas (Enderby Land, Antarctic)

2013 ◽  
Vol 47 ◽  
pp. 167-178 ◽  
Author(s):  
M. P. Andreev
Keyword(s):  
Liquid Water ◽  
Climate Conditions ◽  
Water Ice ◽  
Buellia Frigida ◽  
Antarctic Continent ◽  
Harsh Climate ◽  
The Antarctic ◽  
First Time ◽  
Lichen Flora

Lichen flora and vegetation in the vicinity of the Russian base «Molodyozhnaya» (Enderby Land, Antarctica) were investigated in 2010–2011 in details for the first time. About 500 specimens were collected in 100 localities in all available ecotopes. The lichen flora is the richest in the region and numbers 39 species (21 genera, 11 families). The studied vegetation is very poor and sparse, but typical for coastal oases of the Antarctic continent. The poorness is caused by the extremely harsh climate conditions, insufficient availability of liquid water, ice-free land, and high insolation levels. The dominant and most common lichens are Rinodina olivaceobrunnea, Amandinea punctata, Candelariella flava, Physcia caesia, Caloplaca tominii, Lecanora expectans, Caloplaca ammiospila, Lecidea cancriformis, Pseudephebe minuscula, Lecidella siplei, Umbilicaria decussata, Buellia frigida, Lecanora fuscobrunnea, Usnea sphacelata, Lepraria and Buellia spp.

Sign in / Sign up

Export Citation Format

Share Document