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T V Raudina, S V Loiko, A Lim, R M Manasypov, L S Shirokova, G I Istigechev, D M Kuzmina, S P Kulizhsky, S N Vorobyev, O S Pokrovsky
Soil pore waters are a vital component of the ecosystem as they are efficient tracers of mineral weathering, plant litter leaching, and nutrient uptake by vegetation. In the permafrost environment, maximal hydraulic connectivity and element transport from soils to rivers and lakes occurs via supra-permafrost flow (i.e. water, gases, suspended matter, and solutes migration over the permafrost table). To assess possible consequences of permafrost thaw and climate warming on carbon and Green House gases (GHG) dynamics we used a "substituting space for time" approach in the largest frozen peatland of the world...
April 11, 2018: Science of the Total Environment
Jianling You, Xiaoping Qin, Sailesh Ranjitkar, Stephen C Lougheed, Mingcheng Wang, Wen Zhou, Dongxin Ouyang, Yin Zhou, Jianchu Xu, Wenju Zhang, Yuguo Wang, Ji Yang, Zhiping Song
Climate change profoundly influences species distributions. These effects are evident in poleward latitudinal range shifts for many taxa, and upward altitudinal range shifts for alpine species, that resulted from increased annual global temperatures since the Last Glacial Maximum (LGM, ca. 22,000 BP). For the latter, the ultimate consequence of upward shifts may be extinction as species in the highest alpine ecosystems can migrate no further, a phenomenon often characterized as "nowhere to go". To predict responses to climate change of the alpine plants on the Qinghai-Tibetan Plateau (QTP), we used ecological niche modelling (ENM) to estimate the range shifts of 14 Rhodiola species, beginning with the Last Interglacial (ca...
April 12, 2018: Scientific Reports
Baihui Ren, Yuanman Hu, Baodong Chen, Ying Zhang, Jan Thiele, Rongjiu Shi, Miao Liu, Rencang Bu
In the permafrost region of northeastern China, vegetation and soil environment have showed response to permafrost degradation triggered by global warming, but the corresponding variation of the soil microbial communities remains poorly investigated. Here, a field investigation in the continuous permafrost region was conducted to collect 63 soil samples from 21 sites along a latitudinal gradient to assess the distribution pattern of microbial communities and their correlation with environmental factors. High-throughput Illumina sequencing revealed that bacterial communities were dominated by Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria...
April 4, 2018: Scientific Reports
Jason A Lowe, Daniel Bernie
A number of studies have examined the size of the allowable global cumulative carbon budget compatible with limiting twenty-first century global average temperature rise to below 2°C and below 1.5°C relative to pre-industrial levels. These estimates of cumulative emissions have a number of uncertainties including those associated with the climate sensitivity and the global carbon cycle. Although the IPCC fifth assessment report contained information on a range of Earth system feedbacks, such as carbon released by thawing of permafrost or methane production by wetlands as a result of climate change, the impact of many of these Earth system processes on the allowable carbon budgets remains to be quantified...
May 13, 2018: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Zhijia Ci, Fei Peng, Xian Xue, Xiaoshan Zhang
Soils represent the single largest mercury (Hg) reservoir in the global environment, indicating that a tiny change of Hg behavior in soil ecosystem could greatly affect the global Hg cycle. Climate warming is strongly altering the structure and functions of permafrost and then would influence the Hg cycle in permafrost soils. However, Hg biogeochemistry in climate-sensitive permafrost is poorly investigated. Here we report a data set of soil Hg (0) concentrations in four different depths of the active layer in the Qinghai-Tibet Plateau permafrost...
March 29, 2018: Environmental Pollution
A David McGuire, David M Lawrence, Charles Koven, Joy S Clein, Eleanor Burke, Guangsheng Chen, Elchin Jafarov, Andrew H MacDougall, Sergey Marchenko, Dmitry Nicolsky, Shushi Peng, Annette Rinke, Philippe Ciais, Isabelle Gouttevin, Daniel J Hayes, Duoying Ji, Gerhard Krinner, John C Moore, Vladimir Romanovsky, Christina Schädel, Kevin Schaefer, Edward A G Schuur, Qianlai Zhuang
We conducted a model-based assessment of changes in permafrost area and carbon storage for simulations driven by RCP4.5 and RCP8.5 projections between 2010 and 2299 for the northern permafrost region. All models simulating carbon represented soil with depth, a critical structural feature needed to represent the permafrost carbon-climate feedback, but that is not a universal feature of all climate models. Between 2010 and 2299, simulations indicated losses of permafrost between 3 and 5 million km2 for the RCP4...
March 26, 2018: Proceedings of the National Academy of Sciences of the United States of America
Lyubov A Shmakova, Sergey A Karpov, Stanislav A Malavin, Alexey V Smirnov
A new species, Phalansterium arcticum sp. n., was isolated from an 8580-year-old Arctic permafrost layer. This organism typically lives as a sedentary uniflagellated cell enclosed in a thin flexible mucilaginous sheath, but can form naked swimming cells and amoeboid cells with eruptive pseudopodia accompanied with the formation of short, filopodia-like projections. In an SSU rDNA phylogenetic tree, it robustly groups with other species of this genus. Along with a description of the species, we also add new details to the description of the cell division of Phalansterium and the feeding process in this organism...
March 3, 2018: European Journal of Protistology
Simon van Bellen, Gabriel Magnan, Lauren Davies, Duane Froese, Gillian Mullan-Boudreau, Claudio Zaccone, Michelle Garneau, William Shotyk
Testate amoebae are abundant in the surface layers of northern peatlands. Analysis of their fossilized shell (test) assemblages allows for reconstructions of local water-table depths (WTD). We have reconstructed WTD dynamics for five peat cores from peatlands ranging in distance from the Athabasca bituminous sands (ABS) region in western Canada. Amoeba assemblages were combined with plant macrofossil records, acid-insoluble ash (AIA) fluxes and instrumental climate data to identify drivers for environmental change...
March 23, 2018: Global Change Biology
Claire C Treat, A Anthony Bloom, Maija E Marushchak
Wetlands are the single largest natural source of atmospheric methane (CH4 ), a greenhouse gas, and occur extensively in the northern hemisphere. Large discrepancies remain between "bottom-up" and "top-down" estimates of northern CH4 emissions. To explore whether these discrepancies are due to poor representation of non-growing season CH4 emissions, we synthesized non-growing season and annual CH4 flux measurements from temperate, boreal, and tundra wetlands and uplands. Median non-growing season wetland emissions ranged from 0...
March 22, 2018: Global Change Biology
Michael M Loranty, Logan T Berner, Eric D Taber, Heather Kropp, Susan M Natali, Heather D Alexander, Sergey P Davydov, Nikita S Zimov
Arctic ecosystems are characterized by a broad range of plant functional types that are highly heterogeneous at small (~1-2 m) spatial scales. Climatic changes can impact vegetation distribution directly, and also indirectly via impacts on disturbance regimes. Consequent changes in vegetation structure and function have implications for surface energy dynamics that may alter permafrost thermal dynamics, and are therefore of interest in the context of permafrost related climate feedbacks. In this study we examine small-scale heterogeneity in soil thermal properties and ecosystem carbon and water fluxes associated with varying understory vegetation in open-canopy larch forests in northeastern Siberia...
2018: PloS One
Avinash Sharma, Kunal Jani, Guang-Da Feng, Prachi Karodi, Venkata Ramana Vemuluri, Hong-Hui Zhu, Sisinthy Shivaji, Vishal Thite, Swapnil Kajale, Praveen Rahi, Yogesh Shouche
A Gram-stain-negative, yellowish-orange pigmented, rod-shaped, motile bacterium, designated strain ARC111T , was isolated from sediment of Arctic permafrost at Midtre Lovénbreen glacier, Svalbard. 16S rRNA gene based identification of strain ARC111T demonstrated highest sequence similarities to Subsaxibacter broadyi P7T (97.8 %) and Subsaxibacter arcticus JCM30334T (97.5 %) and ≤95.2 % with all other members of the family Flavobacteriaceae. Phylogenetic analysis revealed the distinct positioning of strain ARC111T within the genus Subsaxibacter...
March 21, 2018: International Journal of Systematic and Evolutionary Microbiology
Jamie R Wood
Ancient samples present a number of technical challenges for DNA barcoding, including damaged DNA with low endogenous copy number and short fragment lengths. Nevertheless, techniques are available to overcome these issues, and DNA barcoding has now been used to successfully recover parasite DNA from a wide variety of ancient substrates, including coprolites, cesspit sediment, mummified tissues, burial sediments and permafrost soils. The study of parasite DNA from ancient samples can provide a number of unique scientific insights, for example: (1) into the parasite communities and health of prehistoric human populations; (2) the ability to reconstruct the natural parasite faunas of rare or extinct host species, which has implications for conservation management and de-extinction; and (3) the ability to view in 'real-time' processes that may operate over century- or millenial-timescales, such as how parasites responded to past climate change events or how they co-evolved alongside their hosts...
March 20, 2018: Parasitology
Isabelle Raymond-Bouchard, Jacqueline Goordial, Yevgen Zolotarov, Jennifer Ronholm, Martina Stromvik, Corien Bakermans, Lyle G Whyte
Permafrost accounts for 27% of all soil ecosystems and harbors diverse microbial communities. Our understanding of microorganisms in permafrost, their activities and adaptations, remains limited. Using five subzero-growing (cryophilic) permafrost bacteria, we examined features of cold adaptation through comparative genomic analyses with mesophilic relatives. The cryophiles possess genes associated with cold adaptation, including cold shock proteins, RNA helicases, and oxidative stress and carotenoid synthesis enzymes...
March 8, 2018: FEMS Microbiology Ecology
Cuicui Mu, Lili Li, Xiaodong Wu, Feng Zhang, Lin Jia, Qian Zhao, Tingjun Zhang
Deep carbon pool in permafrost regions is an important component of the global terrestrial carbon cycle. However, the greenhouse gas production from deep permafrost soils is not well understood. Here, using soils collected from 5-m deep permafrost cores from meadow and wet meadow on the northern Qinghai-Tibetan Plateau (QTP), we investigated the effects of temperature on CO2 and N2 O production under aerobic incubations and CH4 production under anaerobic incubations. After a 35-day incubation, the CO2, N2 O and CH4 production at -2 °C to 10 °C were 0...
March 9, 2018: Scientific Reports
Wenjie Liu, Shengyun Chen, Junyi Liang, Xiang Qin, Shichang Kang, Jiawen Ren, Dahe Qin
The objective of this study is to investigate the effect of decreased permafrost stability on carbon storage of the alpine ecosystems in the northeastern margin of the Qinghai-Tibet Plateau. During July and August 2013, we selected 18 sites in five types of permafrost (stable, substable, transitional, unstable, and extremely unstable) regions. We measured aboveground phytomass carbon (APC) and soil respiration (SR), soil inorganic carbon (SIC), soil organic carbon (SOC), belowground phytomass carbon, and soil properties down to 50 cm at same types of soils and grasslands...
March 8, 2018: Scientific Reports
Sofia Mindlin, Anatoliy Petrenko, Mayya Petrova
A novel mobile genetic element has been identified in small plasmids isolated from permafrost strains of Acinetobacter lwoffii. This element, designated the chrAB dif module, contains the chromium resistance genes chrA and chrB, functionally active both in the original host strains and after transfer into Acinetobacter baylyi. The 3011 bp chrAB dif module is flanked by XerC/XerD recombination sites highly homologous to those of the site-specific recombination system dif/Xer. Analysis of public databases revealed almost identical variants of the chrAB dif module in different plasmids in strains of various Acinetobacter species predominantly inhabiting the environment (A...
March 4, 2018: FEMS Microbiology Letters
Sebastián Duchêne, Edward C Holmes
Pithovirus sibericum is a giant (610 Kpb) double-stranded DNA virus discovered in a purportedly 30,000-year-old permafrost sample. A closely related virus, Pithovirus massiliensis , was recently isolated from a sewer in southern France. An initial comparison of these two virus genomes assumed that P. sibericum was directly ancestral to P. massiliensis and gave a maximum evolutionary rate of 2.60 × 10-5 nucleotide substitutions per site per year (subs/site/year). If correct, this would make pithoviruses among the fastest-evolving DNA viruses, with rates close to those seen in some RNA viruses...
January 2018: Virus Evolution
Xiaoliang Ma, Guimin Liu, Xiaodong Wu, Joseph M Smoak, Linlin Ye, Haiyan Xu, Lin Zhao, Yongjian Ding
The Qinghai-Tibetan plateau (QTP) stores a large amount of soil organic carbon and is the headwater region for several large rivers in Asia. Therefore, it is important to understand the influence of environmental factors on river water quality and the dissolved organic carbon (DOC) export in this region. We examined the water physico-chemical characteristics, DOC concentrations and export rates of 7 rivers under typical land cover types in the Three Rivers Headwater Region during August 2016. The results showed that the highest DOC concentrations were recorded in the rivers within the catchment of alpine wet meadow and meadow...
February 24, 2018: Science of the Total Environment
Lin Zhao, Xiaodong Wu, Zhiwei Wang, Yu Sheng, Hongbing Fang, Yonghua Zhao, Guojie Hu, Wangping Li, Qiangqiang Pang, Jianzong Shi, Bentian Mo, Qian Wang, Xirui Ruan, Xiaodong Li, Yongjian Ding
There are several publications related to the soil organic carbon (SOC) on the Qinghai-Tibetan Plateau (QTP). However, most of these reports were from different parts of the plateau with various sampling depth. Here, we present the results from a systematic sampling and analysis of 200 soil pits. Most of the pits were deeper than 2 m from an east-west transect across the plateau. The SOC and total nitrogen (TN) pools of the 148 × 104  km2 , the area of the permafrost zone, for the upper 2 m soils calculated from the vegetation map were estimated to be 17...
February 26, 2018: Scientific Reports
Lisa Bröder, Tommaso Tesi, August Andersson, Igor Semiletov, Örjan Gustafsson
The burial of terrestrial organic carbon (terrOC) in marine sediments contributes to the regulation of atmospheric CO2 on geological timescales and may mitigate positive feedback to present-day climate warming. However, the fate of terrOC in marine settings is debated, with uncertainties regarding its degradation during transport. Here, we employ compound-specific radiocarbon analyses of terrestrial biomarkers to determine cross-shelf transport times. For the World's largest marginal sea, the East Siberian Arctic shelf, transport requires 3600 ± 300 years for the 600 km from the Lena River to the Laptev Sea shelf edge...
February 23, 2018: Nature Communications
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