scholarly journals Metabolic potential and survival strategies of microbial communities across extreme temperature gradients on Deception Island volcano, Antarctica

Author(s):  
Amanda Gonçalves Bendia ◽  
Leandro Nascimento Lemos ◽  
Lucas William Mendes ◽  
Camila Negrão Signori ◽  
Brendan J. M. Bohannan ◽  
...  
2020 ◽  
Author(s):  
Amanda Gonçalves Bendia ◽  
Leandro Nascimento Lemos ◽  
Lucas William Mendes ◽  
Camila Negrão Signori ◽  
Brendan J. M. Bohannan ◽  
...  

AbstractActive volcanoes in Antarctica, in contrast to the rest of the icy landscape, have remarkable temperature and geochemical gradients that could select for a wide variety of microbial adaptive mechanisms and metabolic pathways. Deception Island is a stratovolcano flooded by the sea, resulting in contrasting ecosystems such as permanent glaciers (<0 °C) and active fumaroles (up to 100 °C). Steep gradients in temperature, salinity and geochemistry over very short distances have been reported for Deception Island, and have been shown to effect microbial community structure and diversity. However, little is known regarding how these gradients affect ecosystem functioning, for example due to inhibition of key metabolic enzymes or pathways. In this study, we used shotgun metagenomics and metagenome-assembled genomes to explore how microbial functional diversity is shaped by extreme geochemical, salinity and temperature gradients in fumarole and glacier sediments. We observed that microbial communities from a 98 °C fumarole harbor specific hyperthermophilic molecular strategies, as well as reductive and autotrophic pathways, while those from <80 °C fumaroles possess more diverse metabolic and survival strategies capable of responding to fluctuating redox and temperature conditions. In contrast, glacier communities showed less diverse metabolic potentials, comprising mainly heterotrophic and carbon pathways. Through the reconstruction of genomes, we were able to clarify putative novel lifestyles of underrepresented taxonomic groups, especially those related to Nanoarchaeota and thermophilic ammonia-oxidizing archaeal lineages. Our results enhance understanding of the metabolic and survival capabilities of different extremophilic lineages of Bacteria and Archaea.


Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1051
Author(s):  
Kun Liu ◽  
Xi Chen ◽  
Kangping Du ◽  
Yu Wang ◽  
Jinguang Du ◽  
...  

The purpose of this paper is to study the thermal shock resistance and failure mechanism of La2Ce2O7/8YSZ double-ceramic-layer thermal barrier coatings (LC/8YSZ DCL TBCs) under extreme temperature gradients. At high surface temperatures, thermal shock and infrared temperature measuring modules were used to determine the thermal cycling life and insulation temperature of LC/8YSZ DCL TBCs under extreme temperature gradients by an oxygen–acetylene gas flame testing machine. A viscoelastic model was used to obtain the stress and strain law of solid phase sintering of a coating system using the finite element method. Results and Conclusion: (1) Thermal cycling life was affected by the surface temperature of LC/8YSZ DCL TBCs and decreased sharply with the increase of surface temperature. (2) The LC ceramic surface of the failure coating was sintered, and the higher the temperature, the faster the sintering process. (3) Accelerated life test results showed that high temperature thermal cycling life is not only related to thermal fatigue of ceramic layer, but is also related to the sintering degree of the coating. (4) Although the high temperature thermal stress had great influence on the coating, great sintering stress was produced with sintering of the LC ceramic layer, which is the main cause of LC/8YSZ DCL TBC failure. The above results indicate that for new TBC ceramic materials, especially those for engines above class F, their sinterability should be fully considered. Sintering affects the thermal shock properties at high temperature. Our research results can provide reference for material selection and high temperature performance research.


2018 ◽  
Author(s):  
Adi Lavy ◽  
David Geller McGrath ◽  
Paula B. Matheus Carnevali ◽  
Jiamin Wan ◽  
Wenming Dong ◽  
...  

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.


Author(s):  
Christen L. Grettenberger ◽  
Trinity L. Hamilton

Acid mine drainage (AMD) is a global problem in which iron sulfide minerals oxidize and generate acidic, metal-rich water. Bioremediation relies on understanding how microbial communities inhabiting an AMD site contribute to biogeochemical cycling. A number of studies have reported community composition in AMD sites from 16S rRNA gene amplicons but it remains difficult to link taxa to function, especially in the absence of closely related cultured species or those with published genomes. Unfortunately, there is a paucity of genomes and cultured taxa from AMD environments. Here, we report 29 novel metagenome assembled genomes from Cabin Branch, an AMD site in the Daniel Boone National Forest, KY, USA. The genomes span 11 bacterial phyla and one Archaea and include taxa that contribute to carbon, nitrogen, sulfur, and iron cycling. These data reveal overlooked taxa that contribute to carbon fixation in AMD sites as well as uncharacterized Fe(II)-oxidizing bacteria. These data provide additional context for 16S rRNA gene studies, add to our understanding of the taxa involved in biogeochemical cycling in AMD environments, and can inform bioremediation strategies. IMPORTANCE Bioremediating acid mine drainage requires understanding how microbial communities influence geochemical cycling of iron and sulfur and biologically important elements like carbon and nitrogen. Research in this area has provided an abundance of 16S rRNA gene amplicon data. However, linking these data to metabolisms is difficult because many AMD taxa are uncultured or lack published genomes. Here, we present metagenome assembled genomes from 29 novel AMD taxa and detail their metabolic potential. These data provide information on AMD taxa that could be important for bioremediation strategies including taxa that are involved in cycling iron, sulfur, carbon, and nitrogen.


2015 ◽  
Vol 95 (3) ◽  
pp. 219-230 ◽  
Author(s):  
Kristine M. Haynes ◽  
Michael D. Preston ◽  
James W. McLaughlin ◽  
Kara Webster ◽  
Nathan Basiliko

Haynes, K. M., Preston, M. D., McLaughlin, J. W., Webster, K. and Basiliko, N. 2015. Dissimilar bacterial and fungal decomposer communities across rich to poor fen peatlands exhibit functional redundancy. Can. J. Soil Sci. 95: 219–230. Climatic and environmental changes can lead to shifts in the dominant vegetation communities present in northern peatland ecosystems, including from Sphagnum- to vascular-dominated systems. Such shifts in vegetation result in changes to the chemical quality of carbon substrates for soil microbial decomposers, with leaves and roots deposited in the peat surface and subsurface that potentially decompose faster. This study characterized the bacterial and fungal communities present along a nutrient gradient ranging from rich to poor fen peatlands and assessed the metabolic potential of these communities to mineralize a variety of organic matter substrates of varying chemical complexity using substrate-induced respiration (SIR) assays. Distinct microbial communities existed between rich, intermediate and poor fens, but SIR in each of the three sites exhibited the same pattern of carbon mineralization, providing support for the concept of functional redundancy, at least under standardized in vitro conditions. Preferential mineralization of simple organic substrates in the rich fen and complex compounds in the poor fen was not observed. Similarly, no preference was given to “native” organic matter extracts derived from each fen, with microbial communities opting for the most bioavailable substrate. This study suggests that soil bacteria and fungi might be able to respond relatively rapidly to shifts in vegetation communities and subsequent changes in the quality of carbon substrate additions to peatlands associated with environmental and climatic change.


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Yanying Zhang ◽  
Juan Ling ◽  
Qingsong Yang ◽  
Chongqing Wen ◽  
Qingyun Yan ◽  
...  

2013 ◽  
Vol 66 (2) ◽  
pp. 322-334 ◽  
Author(s):  
Pattanop Kanokratana ◽  
Wuttichai Mhuantong ◽  
Thanaporn Laothanachareon ◽  
Sithichoke Tangphatsornruang ◽  
Lily Eurwilaichitr ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Pauline Bergsten ◽  
Pauline Vannier ◽  
Alexandra María Klonowski ◽  
Stephen Knobloch ◽  
Magnús Tumi Gudmundsson ◽  
...  

The island of Surtsey was formed in 1963–1967 on the offshore Icelandic volcanic rift zone. It offers a unique opportunity to study the subsurface biosphere in newly formed oceanic crust and an associated hydrothermal-seawater system, whose maximum temperature is currently above 120°C at about 100m below surface. Here, we present new insights into the diversity, distribution, and abundance of microorganisms in the subsurface of the island, 50years after its creation. Samples, including basaltic tuff drill cores and associated fluids acquired at successive depths as well as surface fumes from fumaroles, were collected during expedition 5059 of the International Continental Scientific Drilling Program specifically designed to collect microbiological samples. Results of this microbial survey are investigated with 16S rRNA gene amplicon sequencing and scanning electron microscopy. To distinguish endemic microbial taxa of subsurface rocks from potential contaminants present in the drilling fluid, we use both methodological and computational strategies. Our 16S rRNA gene analysis results expose diverse and distinct microbial communities in the drill cores and the borehole fluid samples, which harbor thermophiles in high abundance. Whereas some taxonomic lineages detected across these habitats remain uncharacterized (e.g., Acetothermiia, Ammonifexales), our results highlight potential residents of the subsurface that could be identified at lower taxonomic rank such as Thermaerobacter, BRH-c8a (Desulfallas-Sporotomaculum), Thioalkalimicrobium, and Sulfurospirillum. Microscopy images reveal possible biotic structures attached to the basaltic substrate. Finally, microbial colonization of the newly formed basaltic crust and the metabolic potential are discussed on the basis of the data.


Sign in / Sign up

Export Citation Format

Share Document