scholarly journals Insight Into Ecology, Metabolic Potential, and the Taxonomic Composition of Bacterial Communities in the Periodic Water Pond on King George Island (Antarctica)

2021 ◽  
Vol 12 ◽  
Author(s):  
Tomasz Krucon ◽  
Lukasz Dziewit ◽  
Lukasz Drewniak
Keyword(s):  
Heterotrophic Bacteria ◽  
Taxonomic Composition ◽  
Shannon Index ◽  
Polar Regions ◽  
Metabolic Potential ◽  
Bacterial Populations ◽  
Carbon And Nitrogen ◽  
Run Off ◽  
Water Pond ◽  
The Antarctic

Polar regions contain a wide variety of lentic ecosystems. These include periodic ponds that have a significant impact on carbon and nitrogen cycling in polar environments. This study was conducted to assess the taxonomic and metabolic diversity of bacteria found in Antarctic pond affected by penguins and sea elephants and to define their role in ongoing processes. Metabolic assays showed that of the 168 tested heterotrophic bacteria present in the Antarctic periodic pond, 96% are able to degrade lipids, 30% cellulose, 26% proteins, and 26% starch. The taxonomic classification of the obtained isolates differs from that based on the composition of the 16S rRNA relative abundances in the studied pond. The dominant Actinobacteria constituting 45% of isolates represents a low proportion of the community, around 4%. With the addition of run-off, the proportions of inhabiting bacteria changed, including a significant decrease in the abundance of Cyanobacteria, from 2.38 to 0.33%, increase of Firmicutes from 9.32 to 19.18%, and a decreasing richness (Chao1 index from 1299 to 889) and diversity (Shannon index from 4.73 to 4.20). Comparative studies of communities found in different Antarctic environments indicate a great role for penguins in shaping bacterial populations.

The genus Chaetoceros (Bacillariophyta) in Arctic and Atarctic

2016 ◽  
Vol 50 ◽  
pp. 56-111 ◽  
Author(s):  
R. M. Gogorev ◽  
N. I. Samsonov
Keyword(s):  
Sea Ice ◽  
Taxonomic Composition ◽  
The Arctic ◽  
Species Number ◽  
Polar Regions ◽  
Arctic Seas ◽  
Cosmopolitan Species ◽  
Number Of Species ◽  
Antarctic Waters ◽  
The Antarctic

A floristic review of the genus Chaetoceros from Arctic and Antarctic waters is undertaken. Taxonomic composition of the Chaetoceros from the Russian Arctic seas, as well as from some regions of the Antarctic was investigated in both water column and sea ice. The genus is rather diverse in both polar regions: 55 species in Arctic and 34 ones in Antarctic. The regions differ in total number of species, number of species belonging to the subgenera Chaetoceros and Hyalochaete and to different sections. Species of the genus are often dominant and the most abundant in Arctic phytoplankton. However, the genus is not prevailing in number of the dominant species as well as in share of the total cell abundance of Antarctic phytoplankton. The importance of the species in sea ice assemblages of the Antarctic is more significant as compared with the Arctic. The Arctic is characterized by cosmopolitan species and those widely distributed in the Northern Hemisphere, more than half of the Chaetoceros taxa are common to all Arctic seas. The Antarctic has a high percentage of endemic Chaetoceros species. Both polar regions are similar in terms of Chaetoceros species composition mainly due to cosmopolitan species.

scholarly journals Contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradient

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Clara Ruiz-González ◽  
Juan Pablo Niño-García ◽  
Martin Berggren ◽  
Paul A. Del Giorgio
Keyword(s):  
Headwater Streams ◽  
Taxonomic Composition ◽  
Environmental Drivers ◽  
Rrna Gene ◽  
Metabolic Potential ◽  
Bacterial Populations ◽  
Biolog Ecoplates ◽  
Environmental Controls ◽  
Hydrologic Gradient ◽  
Bacterioplankton Communities

Freshwater bacterioplankton communities are influenced by the transport of bacteria from the surrounding terrestrial environments. It has been shown that, although most of these dispersed bacteria gradually disappear along the hydrologic continuum, some can thrive in aquatic systems and become dominant, leading to a gradual succession of communities. Here we aimed at exploring the environmental factors driving the structure of such contrasting bacterial populations as well as their functional properties. Using Illumina sequencing of the 16S rRNA gene, we characterized the taxonomic composition of bacterioplankton communities from 10 streams and rivers in Québec spanning the whole hydrologic continuum (river Strahler order 0 to 7), which were sampled in two occasions. With the aim to understand the fate and controls of the transported bacteria, among the taxa present at the origin of the hydrologic gradient (i.e., in the smallest headwater streams) we identified two types of dynamics: i) ‘Tourist’ taxa, which were those that decreased in abundance from the headwaters towards the largest rivers, and ii) ‘Seed’ taxa, those that increased their abundances along the hydrologic continuum. Communities changed gradually from the fast-flowing headwater streams dominated by ‘Tourist’ taxa (ca. 95% of the sequences) towards the largest rivers (Strahler order 4-7) where ‘Seed’ taxa comprised up to 80% of community sequences. Variation in taxonomic composition of the communities dominated by ‘Tourist’ taxa in streams seemed related to different degree of terrestrial inputs, whereas compositional changes in ‘Seed’ communities in the large rivers were linked to differences in autochthonous processes. Finally, the two types of communities differed significantly in their metabolic potential assessed through Biolog Ecoplates. All this suggests that hydrologic transport modulates the gradual replacement of two contrasting population types subjected to different environmental controls and with different metabolic potentials. Moreover, we show that the separate exploration of the two pools of taxa allows unveiling environmental drivers and processes operating on them that remain hidden if explored at the whole community level.

scholarly journals The Diversity, Composition, and Metabolic Pathways of Archaea in Pigs

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2139
Author(s):  
Feilong Deng ◽  
Yushan Li ◽  
Yunjuan Peng ◽  
Xiaoyuan Wei ◽  
Xiaofan Wang ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Antibiotic Resistance Genes ◽  
Alpha Diversity ◽  
Distance Matrix ◽  
Archaeal Community ◽  
Gene Families ◽  
Shannon Index ◽  
Metabolic Potential ◽  
Substantial Progress ◽  
Archaeal Communities

Archaea are an essential class of gut microorganisms in humans and animals. Despite the substantial progress in gut microbiome research in the last decade, most studies have focused on bacteria, and little is known about archaea in mammals. In this study, we investigated the composition, diversity, and functional potential of gut archaeal communities in pigs by re-analyzing a published metagenomic dataset including a total of 276 fecal samples from three countries: China (n = 76), Denmark (n = 100), and France (n = 100). For alpha diversity (Shannon Index) of the archaeal communities, Chinese pigs were less diverse than Danish and French pigs (p < 0.001). Consistently, Chinese pigs also possessed different archaeal community structures from the other two groups based on the Bray–Curtis distance matrix. Methanobrevibacter was the most dominant archaeal genus in Chinese pigs (44.94%) and French pigs (15.41%), while Candidatus methanomethylophilus was the most predominant in Danish pigs (15.71%). At the species level, the relative abundance of Candidatus methanomethylophilus alvus, Natrialbaceae archaeon XQ INN 246, and Methanobrevibacter gottschalkii were greatest in Danish, French, and Chinese pigs with a relative abundance of 14.32, 11.67, and 16.28%, respectively. In terms of metabolic potential, the top three pathways in the archaeal communities included the MetaCyc pathway related to the biosynthesis of L-valine, L-isoleucine, and isobutanol. Interestingly, the pathway related to hydrogen consumption (METHANOGENESIS-PWY) was only observed in archaeal reads, while the pathways participating in hydrogen production (FERMENTATION-PWY and PWY4LZ-257) were only detected in bacterial reads. Archaeal communities also possessed CAZyme gene families, with the top five being AA3, GH43, GT2, AA6, and CE9. In terms of antibiotic resistance genes (ARGs), the class of multidrug resistance was the most abundant ARG, accounting for 87.41% of archaeal ARG hits. Our study reveals the diverse composition and metabolic functions of archaea in pigs, suggesting that archaea might play important roles in swine nutrition and metabolism.

scholarly journals Glacial melt disturbance shifts community metabolism of an Antarctic seafloor ecosystem from net autotrophy to heterotrophy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ulrike Braeckman ◽  
Francesca Pasotti ◽  
Ralf Hoffmann ◽  
Susana Vázquez ◽  
Angela Wulff ◽  
...  
Keyword(s):  
Carbon Balance ◽  
Benthic Communities ◽  
Benthic Primary Production ◽  
Community Metabolism ◽  
West Antarctic ◽  
Run Off ◽  
Net Heterotrophy ◽  
Benthic Ecosystems ◽  
The Antarctic

AbstractClimate change-induced glacial melt affects benthic ecosystems along the West Antarctic Peninsula, but current understanding of the effects on benthic primary production and respiration is limited. Here we demonstrate with a series of in situ community metabolism measurements that climate-related glacial melt disturbance shifts benthic communities from net autotrophy to heterotrophy. With little glacial melt disturbance (during cold El Niño spring 2015), clear waters enabled high benthic microalgal production, resulting in net autotrophic benthic communities. In contrast, water column turbidity caused by increased glacial melt run-off (summer 2015 and warm La Niña spring 2016) limited benthic microalgal production and turned the benthic communities net heterotrophic. Ongoing accelerations in glacial melt and run-off may steer shallow Antarctic seafloor ecosystems towards net heterotrophy, altering the metabolic balance of benthic communities and potentially impacting the carbon balance and food webs at the Antarctic seafloor.

Antarctic notothenioid fishes as subjects for research in evolutionary biology

2000 ◽  
Vol 12 (3) ◽  
pp. 276-287 ◽  
Author(s):  
Joseph T. Eastman
Keyword(s):  
Evolutionary Biology ◽  
Fish Fauna ◽  
Taxonomic Diversity ◽  
Late Eocene ◽  
Taxonomic Composition ◽  
Species Flock ◽  
Subzero Temperatures ◽  
Key Innovation ◽  
The Antarctic ◽  
Upper Slope

Antarctica is a continental island and the waters of its shelf and upper slope are an insular evolutionary site. The shelf waters resemble a closed basin in the Southern Ocean, separated from other continents by distance, current patterns and subzero temperatures. The benthic fish fauna of the shelf and upper slope of the Antarctic Region includes 213 species with higher taxonomic diversity confined to 18 families. Ninety-six notothenioids, 67 liparids and 23 zoarcids comprise 45%, 32% and 11% of the fauna, a combined total of 88%. In high latitude (71–78°S) shelf areas notothenioids dominate abundance and biomass at levels of 90–95%. Notothenioids are also morphologically and ecologically diverse. Although they lack a swim bladder, the hallmark of the notothenioid radiation has been repeated diversification into water column habitats. There are pelagic, semipelagic, cryopelagic and epibenthic species. Notothenioids exhibit the disproportionate speciosity and high endemism characteristic of fish species flock. Antifreeze glycopeptides originating from a transformed trypsinogen gene are a key innovation. It is not known when the modern Antarctic shelf fauna assumed its current taxonomic composition. A late Eocene fossil fauna was taxonomically diverse and cosmopolitan. There was a subsequent faunal replacement with little carryover of families into the modern fauna. Basal notothenioid clades probably diverged in Gondwanan shelf locations during the early Tertiary. Dates inferred from molecular sequences suggest that phyletically derived Antarctic clades arose 15–5 m.y.a.

scholarly journals Evolution in the cold

2000 ◽  
Vol 12 (3) ◽  
pp. 257-257 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Evolutionary Biology ◽  
Antarctic Fish ◽  
The Arctic ◽  
Polar Regions ◽  
Evolutionary Studies ◽  
Adaptive Radiations ◽  
The Antarctic ◽  
The Impact ◽  
Insight Into

Theodosius Dobzhansky once remarked that nothing in biology makes sense other than in the light of evolution, thereby emphasising the central role of evolutionary studies in providing the theoretical context for all of biology. It is perhaps surprising then that evolutionary biology has played such a small role to date in Antarctic science. This is particularly so when it is recognised that the polar regions provide us with an unrivalled laboratory within which to undertake evolutionary studies. The Antarctic exhibits one of the classic examples of a resistance adaptation (antifreeze peptides and glycopeptides, first described from Antarctic fish), and provides textbook examples of adaptive radiations (for example amphipod crustaceans and notothenioid fish). The land is still largely in the grip of major glaciation, and the once rich terrestrial floras and faunas of Cenozoic Gondwana are now highly depauperate and confined to relatively small patches of habitat, often extremely isolated from other such patches. Unlike the Arctic, where organisms are returning to newly deglaciated land from refugia on the continental landmasses to the south, recolonization of Antarctica has had to take place by the dispersal of propagules over vast distances. Antarctica thus offers an insight into the evolutionary responses of terrestrial floras and faunas to extreme climatic change unrivalled in the world. The sea forms a strong contrast to the land in that here the impact of climate appears to have been less severe, at least in as much as few elements of the fauna show convincing signs of having been completely eradicated.

scholarly journals Temporal Distribution of Arsenic and Metals in Soil From King George Island, Antarctica

2022 ◽  
Vol 8 ◽  
Author(s):  
Tailisi H. Trevizani ◽  
Rosalinda C. Montone ◽  
Rubens C. L. Figueira
Keyword(s):  
Human Activities ◽  
Temporal Distribution ◽  
Polar Regions ◽  
Control Points ◽  
King George Island ◽  
Admiralty Bay ◽  
Direct Exposure ◽  
Antarctic Continent ◽  
The Antarctic ◽  
Continue Monitoring

The polar regions are vulnerable to impacts caused by local and global pollution. The Antarctic continent has been considered an environment that has remained little affected by human activities. Direct exposure to contaminants may occur in areas continuously occupied by research stations for several decades. Admiralty Bay on the southeast coast of King George Island, has potential for being affected by human activities due research stations operating in the area, including the Brazilian Commandant Ferraz Antarctic Station (CFAS). The levels of metals and arsenic were determined in soils collected near CFAS (points 5, 6, 7, and 9), Base G and at two points distant from the CFAS: Refuge II and Hennequin. Samples were collected after the fire in CFAS occurred in February 2012, up to December 2018 to assess the environmental impacts in the area. Al and As were related with Base G. Refuge II and Hennequin can be considered as control points for this region. As a consequence of the accident, the increased levels for Cd, Cu, Pb, and Zn, especially at point 9 (inside the CFAS) and in the soil surrounding the CFAS in 2013. The results from 2016 to 2018 demonstrated a reduction in levels of all studied metals near CFAS, which may be related to the leaching of metals into Admiralty Bay; it is thus, being important the continue monitoring soil, sediments, and Antarctic biota.

scholarly journals BRICS in polar regions: Brazil’s interests and prospects

2020 ◽  
Vol 13 (3) ◽  
pp. 326-340
Author(s):  
Paulo Borba Casella ◽  
◽  
Maria Lagutina ◽  
Arthur Roberto Capella Giannattasio ◽  
◽  
...  
Keyword(s):  
Legal Regulation ◽  
The Arctic ◽  
Polar Regions ◽  
Arctic Council ◽  
Public Power ◽  
Promising Tool ◽  
Antarctic Treaty ◽  
International Power ◽  
Global Affairs ◽  
The Antarctic

The current international legal regulation of the Arctic and Antarctica was organized during the second half of the XX century to establish an international public power over the two regions, the Arctic Council (AC) and the Antarctic Treaty System (ATS), which is characterized by Euro-American dominance. However, the rise of emerging countries at the beginning of the XXI century suggests a progressive redefinition of the structural balance of international power in favor of states not traditionally perceived as European and Western. This article examines the role of Brazil within the AC and the ATS to address various polar issues, even institutional ones. As a responsible country in the area of cooperation in science and technology in the oceans and polar regions in BRICS, Brazil appeals to its rich experience in Antarctica and declares its interest in joining the Arctic cooperation. For Brazil, participation in polar cooperation is a way to increase its role in global affairs and BRICS as a negotiating platform. It is seen in this context as a promising tool to achieve this goal. This article highlights new paths in the research agenda concerning interests and prospects of Brazilian agency in the polar regions.

scholarly journals Microbial communities across a hillslope-riparian transect shaped by proximity to the stream, groundwater table, and weathered bedrock

2018 ◽  
Author(s):  
Adi Lavy ◽  
David Geller McGrath ◽  
Paula B. Matheus Carnevali ◽  
Jiamin Wan ◽  
Wenming Dong ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Riparian Zone ◽  
Limited Information ◽  
Metabolic Potential ◽  
Carbon And Nitrogen ◽  
East River ◽  
Mountainous Watersheds ◽  
Geochemical Analyses ◽  
Selenium Reduction ◽  
And Function

AbstractWatersheds are important suppliers of freshwater for human societies. Within mountainous watersheds, microbial communities impact water chemistry and element fluxes as water from precipitation events discharges through soils and underlying weathered rock, yet there is limited information regarding the structure and function of these communities. Within the East River, CO watershed, we conducted a depth-resolved, hillslope to riparian zone transect study to identify factors that control how microorganisms are distributed and their functions. Metagenomic and geochemical analyses indicate that distance from the East River and proximity to groundwater and underlying weathered shale strongly impact microbial community structure and metabolic potential. Riparian zone microbial communities are compositionally distinct from all hillslope communities. Bacteria from phyla lacking isolated representatives consistently increase in abundance with increasing depth, but only in the riparian zone saturated sediments did we find Candidate Phyla Radiation bacteria. Riparian zone microbial communities are functionally differentiated from hillslope communities based on their capacities for carbon and nitrogen fixation and sulfate reduction. Selenium reduction is prominent at depth in weathered shale and saturated riparian zone sediments. We anticipate that the drivers of community composition and metabolic potential identified throughout the studied transect will predict patterns across the larger watershed hillslope system.

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