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https://www.readbyqxmd.com/read/28726195/effects-of-secondary-metabolites-of-permafrost-bacillus-sp-on-cytokine-synthesis-by-human-peripheral-blood-mononuclear-cells
#1
L F Kalenova, S S Kolyvanova, A S Bazhin, I M Besedin, V P Mel'nikov
We studied the effects of secondary metabolites of Bacillus sp. isolated from late Neogene permafrost on secretion of proinflammatory (TNF-α, IL-1β, IL-8, IL-2, and IFNγ) and antiinflammatory (IL-4 and IL-10) cytokines by human peripheral blood mononuclear cells. It was found that metabolites of Bacillus sp. produced more potent effect on cytokine secretion than mitogen phytohemagglutinin and metabolites of Bacillus cereus, medicinal strain IP5832. Activity of metabolites depended on the temperature of bacteria incubation...
July 18, 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28725016/strong-geologic-methane-emissions-from-discontinuous-terrestrial-permafrost-in-the-mackenzie-delta-canada
#2
Katrin Kohnert, Andrei Serafimovich, Stefan Metzger, Jörg Hartmann, Torsten Sachs
Arctic permafrost caps vast amounts of old, geologic methane (CH4) in subsurface reservoirs. Thawing permafrost opens pathways for this CH4 to migrate to the surface. However, the occurrence of geologic emissions and their contribution to the CH4 budget in addition to recent, biogenic CH4 is uncertain. Here we present a high-resolution (100 m × 100 m) regional (10,000 km²) CH4 flux map of the Mackenzie Delta, Canada, based on airborne CH4 flux data from July 2012 and 2013. We identify strong, likely geologic emissions solely where the permafrost is discontinuous...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28715138/microbial-functional-diversity-covaries-with-permafrost-thaw-induced-environmental-heterogeneity-in-tundra-soil
#3
Mengting M Yuan, Jin Zhang, Kai Xue, Liyou Wu, Ye Deng, Jie Deng, Lauren Hale, Xishu Zhou, Zhili He, Yunfeng Yang, Joy D Van Nostrand, Edward A G Schuur, Konstantinos T Konstantinidis, C Ryan Penton, James R Cole, James M Tiedje, Yiqi Luo, Jizhong Zhou
Permafrost soil in high latitude tundra is one of the largest terrestrial carbon (C) stocks and is highly sensitive to climate warming. Understanding microbial responses to warming induced environmental changes are critical to evaluating their influences on soil biogeochemical cycles. In this study, a functional gene array (i.e. GeoChip 4.2) was used to analyze the functional capacities of soil microbial communities collected from a naturally degrading permafrost region in Central Alaska. Varied thaw history was reported to be the main driver of soil and plant differences across a gradient of minimally, moderately and extensively thawed sites...
July 17, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28711847/vertical-patterns-and-controls-of-soil-nutrients-in-alpine-grassland-implications-for-nutrient-uptake
#4
Liming Tian, Lin Zhao, Xiaodong Wu, Hongbing Fang, Yonghua Zhao, Guangyang Yue, Guimin Liu, Hao Chen
Vertical patterns and determinants of soil nutrients are critical to understand nutrient cycling in high-altitude ecosystems; however, they remain poorly understood in the alpine grassland due to lack of systematic field observations. In this study, we examined vertical distributions of soil nutrients and their influencing factors within the upper 1m of soil, using data of 68 soil profiles surveyed in the alpine grassland of the eastern Qinghai-Tibet Plateau. Soil organic carbon (SOC) and total nitrogen (TN) stocks decreased with depth in both alpine meadow (AM) and alpine steppe (AS), but remain constant along the soil profile in alpine swamp meadow (ASM)...
July 13, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28704670/cryo-conditioned-rocky-coast-systems-a-case-study-from-wilczekodden-svalbard
#5
M C Strzelecki, M Kasprzak, M Lim, Z M Swirad, M Jaskólski, Ł Pawłowski, P Modzel
This paper presents the results of an investigation into the processes controlling development of a cryo-conditioned rock coast system in Hornsund, Svalbard. A suite of nested geomorphological and geophysical methods have been applied to characterise the functioning of rock cliffs and shore platforms influenced by lithological control and geomorphic processes driven by polar coast environments. Electrical resistivity tomosgraphy (ERT) surveys have been used to investigate permafrost control on rock coast dynamics and reveal the strong interaction with marine processes in High Arctic coastal settings...
July 10, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28696425/microbial-survival-strategies-in-ancient-permafrost-insights-from-metagenomics
#6
Rachel Mackelprang, Alexander Burkert, Monica Haw, Tara Mahendrarajah, Christopher H Conaway, Thomas A Douglas, Mark P Waldrop
In permafrost (perennially frozen ground) microbes survive oligotrophic conditions, sub-zero temperatures, low water availability and high salinity over millennia. Viable life exists in permafrost tens of thousands of years old but we know little about the metabolic and physiological adaptations to the challenges presented by life in frozen ground over geologic time. In this study we asked whether increasing age and the associated stressors drive adaptive changes in community composition and function. We conducted deep metagenomic and 16 S rRNA gene sequencing across a Pleistocene permafrost chronosequence from 19 000 to 33 000 years before present (kyr)...
July 11, 2017: ISME Journal
https://www.readbyqxmd.com/read/28686892/anaerobic-oxidation-of-methane-by-aerobic-methanotrophs-in-sub-arctic-lake-sediments
#7
Karla Martinez-Cruz, Mary-Cathrine Leewis, Ian Charold Herriott, Armando Sepulveda-Jauregui, Katey Walter Anthony, Frederic Thalasso, Mary Beth Leigh
Anaerobic oxidation of methane (AOM) is a biological process that plays an important role in reducing the CH4 emissions from a wide range of ecosystems. Arctic and sub-Arctic lakes are recognized as significant contributors to global methane (CH4) emission, since CH4 production is increasing as permafrost thaws and provides fuels for methanogenesis. Methanotrophy, including AOM, is critical to reducing CH4 emissions. The identity, activity, and metabolic processes of anaerobic methane oxidizers are poorly understood, yet this information is critical to understanding CH4 cycling and ultimately to predicting future CH4 emissions...
July 4, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28683427/impacts-of-climate-warming-on-the-frozen-ground-and-eco-hydrology-in-the-yellow-river-source-region-china
#8
Yue Qin, Dawen Yang, Bing Gao, Taihua Wang, Jinsong Chen, Yun Chen, Yuhan Wang, Guanheng Zheng
The Yellow River source region is located in the transition region between permafrost and seasonally frozen ground on the northeastern Qinghai-Tibet Plateau. The region has experienced severe climate change, especially air temperature increases, in past decades. In this study, we employed a geomorphology-based eco-hydrological model (GBEHM) to assess the impacts of climate change on the frozen ground and eco-hydrological processes in the region. Based on a long-term simulation from 1981 to 2015, we found that the areal mean maximum thickness of seasonally frozen ground ranged from 1...
July 3, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28675586/experimentally-increased-nutrient-availability-at-the-permafrost-thaw-front-selectively-enhances-biomass-production-of-deep-rooting-subarctic-peatland-species
#9
Frida Keuper, Ellen Dorrepaal, Peter M van Bodegom, Richard van Logtestijn, Gemma Venhuizen, Jurgen van Hal, Rien Aerts
Climate warming increases nitrogen (N) mineralization in superficial soil layers (the dominant rooting zone) of subarctic peatlands. Thawing and subsequent mineralization of permafrost increases plant-available N around the thaw-front. Because plant production in these peatlands is N-limited, such changes may substantially affect net primary production and species composition. We aimed to identify the potential impact of increased N-availability due to permafrost thawing on subarctic peatland plant production and species performance, relative to the impact of increased N-availability in superficial organic layers...
July 4, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28667847/unraveling-of-permafrost-hydrological-variabilities-on-central-qinghai-tibet-plateau-using-stable-isotopic-technique
#10
Yuzhong Yang, Qingbai Wu, Yandong Hou, Zhongqiong Zhang, Jing Zhan, Siru Gao, Huijun Jin
Permafrost degradation on the Qinghai-Tibet Plateau (QTP) will substantially alter the surface runoff discharge and generation, which changes the recharge processes and influences the hydrological cycle on the QTP. Hydrological connections between different water bodies and the influence of thawing permafrost (ground ice) are not well understood on the QTP. This study applied water stable isotopic method to investigate the permafrost hydrological variabilities in Beiluhe Basin (BLB) on the QTP. Isotopic variations of precipitation, river flow, thermokarst lake, and ground ice were identified to figure out the moisture source of them, and to elaborate the hydrological connections in permafrost...
June 28, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28649867/study-of-isotopes-of-carbon-thorium-and-uranium-in-travertine-and-thermal-spring-samples-implications-for-effects-of-changes-in-geochemical-environment-and-processes
#11
Alexander I Malov
Data on modern radiocarbon activity in the old travertine formations of the Pymvashor hydrothermal system were used, in combination with (230)Th/U dating of the travertine, to estimate the (14)C contents of the total dissolved inorganic carbon in the ancient thermal water at the time of precipitation of the travertine ((14)Ccalc). With the known values of (14)Ccalc and average age of the thermal water, and under the assumption that the residence time of the water in aquifer was constant over the last 13.9 ± 1...
June 26, 2017: Isotopes in Environmental and Health Studies
https://www.readbyqxmd.com/read/28649233/microbial-community-response-to-terrestrially-derived-dissolved-organic-matter-in-the-coastal-arctic
#12
Rachel E Sipler, Colleen T E Kellogg, Tara L Connelly, Quinn N Roberts, Patricia L Yager, Deborah A Bronk
Warming at nearly twice the global rate, higher than average air temperatures are the new 'normal' for Arctic ecosystems. This rise in temperature has triggered hydrological and geochemical changes that increasingly release carbon-rich water into the coastal ocean via increased riverine discharge, coastal erosion, and the thawing of the semi-permanent permafrost ubiquitous in the region. To determine the biogeochemical impacts of terrestrially derived dissolved organic matter (tDOM) on marine ecosystems we compared the nutrient stocks and bacterial communities present under ice-covered and ice-free conditions, assessed the lability of Arctic tDOM to coastal microbial communities from the Chukchi Sea, and identified bacterial taxa that respond to rapid increases in tDOM...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28647153/organic-matter-properties-of-fennoscandian-ecosystems-potential-oxidation-of-northern-environments-under-future-change
#13
Gareth D Clay, Fred Worrall, Rebecca Plummer, Catherine S Moody
The oxidative ratio (OR) of an ecosystem, which reflects the ratio of O2:CO2 associated with ecosystem gas exchanges, is an important parameter in understanding the sink of CO2 represented by the terrestrial biosphere. There is a growing body of ecosystem-based approaches to understand OR; however, there are still a number of unknowns. This study addressed two gaps in our understanding of the oxidation of the terrestrial biosphere: (1) What is the oxidation state of Arctic ecosystems, and in particular permafrost soils? (2) Will coupled climate and land use change cause the terrestrial organic matter oxidation state to change? The study considered eight locations along a transect from southern Sweden to northern Norway and sampled different organic matter types (soil, litter, trees, and herbaceous vegetation) as well as different soil orders (Inceptisols, Spodosols, Histosols, and Gelisols)...
June 21, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28639616/current-rates-and-mechanisms-of-subsea-permafrost-degradation-in-the-east-siberian-arctic-shelf
#14
Natalia Shakhova, Igor Semiletov, Orjan Gustafsson, Valentin Sergienko, Leopold Lobkovsky, Oleg Dudarev, Vladimir Tumskoy, Michael Grigoriev, Alexey Mazurov, Anatoly Salyuk, Roman Ananiev, Andrey Koshurnikov, Denis Kosmach, Alexander Charkin, Nicolay Dmitrevsky, Victor Karnaukh, Alexey Gunar, Alexander Meluzov, Denis Chernykh
The rates of subsea permafrost degradation and occurrence of gas-migration pathways are key factors controlling the East Siberian Arctic Shelf (ESAS) methane (CH4) emissions, yet these factors still require assessment. It is thought that after inundation, permafrost-degradation rates would decrease over time and submerged thaw-lake taliks would freeze; therefore, no CH4 release would occur for millennia. Here we present results of the first comprehensive scientific re-drilling to show that subsea permafrost in the near-shore zone of the ESAS has a downward movement of the ice-bonded permafrost table of ∼14 cm year(-1) over the past 31-32 years...
June 22, 2017: Nature Communications
https://www.readbyqxmd.com/read/28630484/simulated-responses-of-permafrost-distribution-to-climate-change-on-the-qinghai-tibet-plateau
#15
Qing Lu, Dongsheng Zhao, Shaohong Wu
Climate warming causes changes in permafrost distribution, which affects the surface energy balance, hydrologic cycle and carbon flux in cold regions. In this study, the Surface Frost Number model was applied to examine permafrost distribution on the Qinghai-Tibet Plateau (QTP) under the four RCPs (RCP2.6, RCP4.5, RCP6.0, and RCP8.5). The Kappa statistic was used to evaluate model results by comparing simulations of baseline permafrost distribution (1981-2010) with the existing frozen soil maps. The comparison shows that the Surface Frost Number model is suitable for simulating the general characteristics of permafrost distribution on the QTP...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28605857/effects-of-warming-and-nitrogen-fertilization-on-ghg-flux-in-an-alpine-swamp-meadow-of-a-permafrost-region
#16
Xiaopeng Chen, Genxu Wang, Tao Zhang, Tianxu Mao, Da Wei, Chunlin Song, Zhaoyong Hu, Kewei Huang
Uncertainties in the seasonal changes of greenhouse gases (GHG) fluxes in wetlands limit our accurate understanding of the responses of permafrost ecosystems to future warming and increased nitrogen (N) deposition. Therefore, in an alpine swamp meadow in the hinterland of the Qinghai-Tibet Plateau, a simulated warming with N fertilization experiment was conducted to investigate the key GHG fluxes (ecosystem respiration [Re], CH4 and N2O) in the early (EG), mid (MG) and late (LG) growing seasons. Results showed that warming (6...
June 8, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28582744/active-layer-monitoring-at-calm-s-site-near-j-g-mendel-station-james-ross-island-eastern-antarctic-peninsula
#17
Filip Hrbáček, Michaela Kňažková, Daniel Nývlt, Kamil Láska, Carsten W Mueller, Jakub Ondruch
The Circumpolar Active Layer Monitoring - South (CALM-S) site was established in February 2014 on James Ross Island as the first CALM-S site in the eastern Antarctic Peninsula region. The site, located near Johann Gregor Mendel Station, is labelled CALM-S JGM. The grid area is gently sloped (<3°) and has an elevation of between 8 and 11ma.s.l. The lithology of the site consists of the muddy sediments of Holocene marine terrace and clayey-sandy Cretaceous sedimentary rocks, which significantly affect the texture, moisture content, and physical parameters of the ground within the grid...
June 3, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28582735/carbon-dioxide-methane-and-nitrous-oxide-fluxes-from-a-fire-chronosequence-in-subarctic-boreal-forests-of-canada
#18
Egle Köster, Kajar Köster, Frank Berninger, Heidi Aaltonen, Xuan Zhou, Jukka Pumpanen
Forest fires are one of the most important natural disturbances in boreal forests, and their occurrence and severity are expected to increase as a result of climate warming. A combination of factors induced by fire leads to a thawing of the near-surface permafrost layer in subarctic boreal forest. Earlier studies reported that an increase in the active layer thickness results in higher carbon dioxide (CO2) and methane (CH4) emissions. We studied changes in CO2, CH4 and nitrous oxide (N2O) fluxes in this study, and the significance of several environmental factors that influence the greenhouse gas (GHG) fluxes at three forest sites that last had fires in 2012, 1990 and 1969, and we compared these to a control area that had no fire for at least 100years...
June 2, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28574203/microbial-network-phylogenetic-diversity-and-community-membership-in-the-active-layer-across-a-permafrost-thaw-gradient
#19
Rhiannon Mondav, Carmody K McCalley, Suzanne B Hodgkins, Steve Frolking, Scott R Saleska, Virginia I Rich, Jeff P Chanton, Patrick M Crill
Biogenic production and release of methane (CH4 ) from thawing permafrost has the potential to be a strong source of radiative forcing. We investigated changes in the active layer microbial community of three sites representative of distinct permafrost thaw stages at a palsa mire in northern Sweden. The palsa sites with intact permafrost, and low radiative forcing signature had a phylogenetically clustered community dominated by Acidobacteria and Proteobacteria. The bog with thawing permafrost and low radiative forcing signature was dominated by hydrogenotrophic methanogens and Acidobacteria, had lower alpha diversity, and midrange phylogenetic clustering, characteristic of ecosystem disturbance affecting habitat filtering, shifting from palsa-like to fen-like at the waterline...
June 2, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28559346/increased-nitrous-oxide-emissions-from-arctic-peatlands-after-permafrost-thaw
#20
Carolina Voigt, Maija E Marushchak, Richard E Lamprecht, Marcin Jackowicz-Korczyński, Amelie Lindgren, Mikhail Mastepanov, Lars Granlund, Torben R Christensen, Teemu Tahvanainen, Pertti J Martikainen, Christina Biasi
Permafrost in the Arctic is thawing, exposing large carbon and nitrogen stocks for decomposition. Gaseous carbon release from Arctic soils due to permafrost thawing is known to be substantial, but growing evidence suggests that Arctic soils may also be relevant sources of nitrous oxide (N2O). Here we show that N2O emissions from subarctic peatlands increase as the permafrost thaws. In our study, the highest postthaw emissions occurred from bare peat surfaces, a typical landform in permafrost peatlands, where permafrost thaw caused a fivefold increase in emissions (0...
June 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
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