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Permafrost

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https://www.readbyqxmd.com/read/28766706/warming-effects-on-permafrost-ecosystem-carbon-fluxes-associated-with-plant-nutrients
#1
Fei Li, Yunfeng Peng, Susan M Natali, Kelong Chen, Tianfeng Han, Guibiao Yang, Jinzhi Ding, Dianye Zhang, Guanqin Wang, Jun Wang, Jianchun Yu, Futing Liu, Yuanhe Yang
Large uncertainties exist in carbon (C)-climate feedback in permafrost regions, partly due to an insufficient understanding of warming effects on nutrient availabilities and their subsequent impacts on vegetation C sequestration. Although a warming climate may promote a substantial release of soil C to the atmosphere, a warming-induced increase in soil nutrient availability may enhance plant productivity, thus offsetting C loss from microbial respiration. Here, we present evidence that the positive temperature effect on carbon dioxide (CO2 ) fluxes may be weakened by reduced plant nitrogen (N) and phosphorous (P) concentrations in a Tibetan permafrost ecosystem...
August 2, 2017: Ecology
https://www.readbyqxmd.com/read/28750228/radionuclides-and-soil-properties-as-indicators-of-glacier-retreat-in-a-recently-deglaciated-permafrost-environment-of-the-maritime-antarctica
#2
Ana Navas, Marc Oliva, Jesús Ruiz-Fernández, Leticia Gaspar, Laura Quijano, Iván Lizaga
Many ice-free environments in Maritime Antarctica are undergoing rapid and substantial environmental changes in response to recent climate trends. This is the case of Elephant Point (Livingston Island, South Shetland Islands, SSI), where the glacier retreat recorded during the last six decades exposed 17% of this small peninsula, namely a moraine extending from the western to the eastern coastlines and a relatively flat proglacial surface. In the southern margin of the peninsula, a sequence of Holocene raised beaches and several bedrock plateaus are also distributed...
July 21, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28749495/characterization-of-a-highly-efficient-antibiotic-degrading-metallo-%C3%AE-lactamase-obtained-from-an-uncultured-member-of-a-permafrost-community
#3
Marcelo Monteiro Pedroso, Christopher Selleck, Charmaine Enculescu, Jeffrey R Harmer, Nataša Mitić, Whitney R Craig, Waleed Helweh, Philip Hugenholtz, Gene W Tyson, David L Tierney, James A Larrabee, Gerhard Schenk
Antibiotic resistance is a major global health problem, one that threatens to derail the benefits garnered from arguably the greatest success of modern medicine, the discovery of antibiotics. Among the most potent agents contributing to antibiotic resistance are metallo-β-lactamases (MBLs). The discovery of MBL-like enzymes in microorganisms that are not in contact with the human population is of particular concern as these proteins already have the in-built capacity to inactivate antibiotics, even though they may not need MBL activity for their survival...
August 16, 2017: Metallomics: Integrated Biometal Science
https://www.readbyqxmd.com/read/28745515/hydrology-of-the-north-klondike-river-carbon-export-water-balance-and-inter-annual-climate-influences-within-a-sub-alpine-permafrost-catchment
#4
Anthony Lapp, Ian Clark, Andrew Macumber, Tim Patterson
Arctic and sub-arctic watersheds are undergoing significant changes due to recent climate warming and degrading permafrost, engendering enhanced monitoring of arctic rivers. Smaller catchments provide understanding of discharge, solute flux and groundwater recharge at the process level that contributes to an understanding of how larger arctic watersheds are responding to climate change. The North Klondike River, located in west central Yukon, is a sub-alpine permafrost catchment, which maintains an active hydrological monitoring station with a record of >40 years...
July 26, 2017: Isotopes in Environmental and Health Studies
https://www.readbyqxmd.com/read/28742066/a-comprehensive-data-set-of-lake-surface-water-temperature-over-the-tibetan-plateau-derived-from-modis-lst-products-2001-2015
#5
Wei Wan, Huan Li, Hongjie Xie, Yang Hong, Di Long, Limin Zhao, Zhongying Han, Yaokui Cui, Baojian Liu, Cunguang Wang, Wenting Yang
Lake surface water temperature (LSWT) is sensitive to long-term changes in thermal structure of lakes and regional air temperature. In the context of global climate change, recent studies showed a significant warming trend of LSWT based on investigating 291 lakes (71% are large lakes, ≥50 km(2) each) globally. However, further efforts are needed to examine variation in LSWT at finer regional spatial and temporal scales. The Tibetan Plateau (TP), known as 'the Roof of the World' and 'Asia's water towers', exerts large influences on and is sensitive to regional and even global climates...
July 25, 2017: Scientific Data
https://www.readbyqxmd.com/read/28735090/impacts-of-the-2003-and-2015-summer-heatwaves-on-permafrost-affected-rock-walls-in-the-mont-blanc-massif
#6
L Ravanel, F Magnin, P Deline
Rockfall is one of the main geomorphological processes that affects the evolution and stability of rock-walls. At high elevations, rockfall is largely climate-driven, very probably because of the warming of rock-wall permafrost. So with the ongoing global warming that drives the degradation of permafrost, the related hazards for people and infrastructure could continue to increase. The heatwave of summer 2015, which affected Western Europe from the end of June to August, had a serious impact on the stability of high-altitude rock-walls, including those in the Mont Blanc massif...
July 20, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28726195/effects-of-secondary-metabolites-of-permafrost-bacillus-sp-on-cytokine-synthesis-by-human-peripheral-blood-mononuclear-cells
#7
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...
June 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
#8
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
#9
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
#10
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
#11
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 tomography (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 26, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28696425/microbial-survival-strategies-in-ancient-permafrost-insights-from-metagenomics
#12
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
#13
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
#14
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...
December 15, 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
#15
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
#16
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 Central QTP. Isotopic variations of precipitation, river flow, thermokarst lake, and near-surface ground ice were identified to figure out the moisture source of them, and to elaborate the hydrological connections in permafrost region...
December 15, 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
#17
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
#18
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
#19
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
#20
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
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