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Heike H Zimmermann, Elena Raschke, Laura S Epp, Kathleen R Stoof-Leichsenring, Lutz Schirrmeister, Georg Schwamborn, Ulrike Herzschuh
Ecosystem boundaries, such as the Arctic-Boreal treeline, are strongly coupled with climate and were spatially highly dynamic during past glacial-interglacial cycles. Only a few studies cover vegetation changes since the last interglacial, as most of the former landscapes are inundated and difficult to access. Using pollen analysis and sedimentary ancient DNA (sedaDNA) metabarcoding, we reveal vegetation changes on Bol'shoy Lyakhovsky Island since the last interglacial from permafrost sediments. Last interglacial samples depict high levels of floral diversity with the presence of trees (Larix, Picea, Populus) and shrubs (Alnus, Betula, Ribes, Cornus, Saliceae) on the currently treeless island...
October 13, 2017: Genes
Craig E Williamson, Sasha Madronich, Aparna Lal, Richard G Zepp, Robyn M Lucas, Erin P Overholt, Kevin C Rose, S Geoffrey Schladow, Julia Lee-Taylor
Climate change is accelerating the release of dissolved organic matter (DOM) to inland and coastal waters through increases in precipitation, thawing of permafrost, and changes in vegetation. Our modeling approach suggests that the selective absorption of ultraviolet radiation (UV) by DOM decreases the valuable ecosystem service wherein sunlight inactivates waterborne pathogens. Here we highlight the sensitivity of waterborne pathogens of humans and wildlife to solar UV, and use the DNA action spectrum to model how differences in water transparency and incident sunlight alter the ability of UV to inactivate waterborne pathogens...
October 12, 2017: Scientific Reports
M A de Pablo, M Ramos, A Molina, M Prieto
A new Circumpolar Active Layer Monitoring (CALM) site was established in 2009 at the Limnopolar Lake watershed in Byers Peninsula, Livingston Island, Antarctica, to provide a node in the western Antarctic Peninsula, one of the regions that recorded the highest air temperature increase in the planet during the last decades. The first detailed analysis of the temporal and spatial evolution of the thaw depth at the Limnopolar Lake CALM-S site is presented here, after eight years of monitoring. The average values range between 48 and 29cm, decreasing at a ratio of 16cm/decade...
October 7, 2017: Science of the Total Environment
Vladimir S Cheptsov, Elena A Vorobyova, Natalia A Manucharova, Mikhail V Gorlenko, Anatoli K Pavlov, Maria A Vdovina, Vladimir N Lomasov, Sergey A Bulat
This research aimed to investigate the viability and biodiversity of microbial communities within ancient Arctic permafrost after exposure to a gamma-radiation dose of 100 kGy at low temperature (- 50 °C), low pressure (1 Torr) and dehydration conditions. The main objective was to assess the possibility for long-term survival of Earth-bound microorganisms in the subsurface of Martian regolith or inside small space bodies at constant absorption and accumulation of the gamma radiation dose. Investigated microbial communities had shown high resistance to a simulated Martian environment...
October 9, 2017: Extremophiles: Life Under Extreme Conditions
Agata Zaborska
Although primary sources of anthropogenic (137)Cs have decreased nowadays, the Arctic is exposed to a variety of secondary sources. These include riverine run-off, oceanic currents, drifting sea ice, melting glaciers and permafrost. Recent reports underline the role of glaciers, specifically cryoconite holes, in radionuclide accumulation. Therefore, this study investigates the hypothesis that melting glaciers are an important means of delivering (137)Cs for Arctic fjord (Hornsund, Svalbard). As marine sediments are the final sink for most contaminants, seven 30-40 cm long sediment cores collected in 2016 were investigated for (137)Cs activity concentration...
October 4, 2017: Journal of Environmental Radioactivity
Mette Bendixen, Lars Lønsmann Iversen, Anders Anker Bjørk, Bo Elberling, Andreas Westergaard-Nielsen, Irina Overeem, Katy R Barnhart, Shfaqat Abbas Khan, Jason E Box, Jakob Abermann, Kirsty Langley, Aart Kroon
Climate changes are pronounced in Arctic regions and increase the vulnerability of the Arctic coastal zone. For example, increases in melting of the Greenland Ice Sheet and reductions in sea ice and permafrost distribution are likely to alter coastal morphodynamics. The deltas of Greenland are largely unaffected by human activity, but increased freshwater runoff and sediment fluxes may increase the size of the deltas, whereas increased wave activity in ice-free periods could reduce their size, with the net impact being unclear until now...
October 4, 2017: Nature
Ziming Yang, Sihang Yang, Joy D Van Nostrand, Jizhong Zhou, Wei Fang, Qi Qi, Yurong Liu, Stan D Wullschleger, Liyuan Liang, David E Graham, Yunfeng Yang, Baohua Gu
Microbial decomposition of soil organic carbon (SOC) in thawing Arctic permafrost is important in determining greenhouse gas feedbacks of tundra ecosystems to climate. However, the changes in microbial community structure during SOC decomposition are poorly known. Here we examine these changes using frozen soils from Barrow, Alaska, USA, in anoxic microcosm incubation at -2 and 8°C for 122 days. The functional gene array GeoChip was used to determine microbial community structure and the functional genes associated with SOC degradation, methanogenesis, and Fe(III) reduction...
2017: Frontiers in Microbiology
Collin P Ward, Sarah G Nalven, Byron C Crump, George W Kling, Rose M Cory
In sunlit waters, photochemical alteration of dissolved organic carbon (DOC) impacts the microbial respiration of DOC to CO2. This coupled photochemical and biological degradation of DOC is especially critical for carbon budgets in the Arctic, where thawing permafrost soils increase opportunities for DOC oxidation to CO2 in surface waters, thereby reinforcing global warming. Here we show how and why sunlight exposure impacts microbial respiration of DOC draining permafrost soils. Sunlight significantly increases or decreases microbial respiration of DOC depending on whether photo-alteration produces or removes molecules that native microbial communities used prior to light exposure...
October 3, 2017: Nature Communications
Elena Kashuba, Alexey A Dmitriev, Shady Mansour Kamal, Ojar Melefors, Gennady Griva, Ute Römling, Ingemar Ernberg, Vladimir Kashuba, Anatoli Brouchkov
Background: Permafrost preserves a variety of viable ancient microorganisms. Some of them can be cultivated after being kept at subzero temperatures for thousands or even millions of years. Objective: To cultivate bacterial strains from permafrost. Design: We isolated and cultivated two bacterial strains from permafrost that was obtained at Mammoth Mountain in Siberia and attributed to the Middle Miocene. Bacterial genomic DNA was sequenced with 40-60× coverage and high-quality contigs were assembled. The first strain was assigned to Staphylococcus warneri species (designated MMP1) and the second one to Staphylococcus hominis species (designated MMP2), based on the classification of 16S ribosomal RNA genes and genomic sequences...
2017: Microbial Ecology in Health and Disease
Maura Lousada, Pedro Pina, Gonçalo Vieira, Lourenço Bandeira, Carla Mora
The main objective of this paper is to verify the accuracy of delineating and characterizing ice-wedge polygonal networks with features exclusively extracted from remotely sensed images of very high resolution. This kind of mapping plays a key role for quantifying ice-wedge degradation in warming permafrost. The evaluation of mapping a network is performed in this study with two sets of aerial images that are compared to ground reference data determined by fieldwork on the same network, located in Adventdalen, Svalbard (78°N)...
September 24, 2017: Science of the Total Environment
Xiaodong Wu, Lin Zhao, Guojie Hu, Guimin Liu, Wangping Li, Yongjian Ding
Permafrost degradation can stimulate the decomposition of organic soil matter and cause a large amount of greenhouse gas emissions into the atmosphere. The light fraction organic matter (LFOM) is a labile substrate for microbial decomposition and probably plays an important role in future permafrost carbon cycles. However, little is known about the distribution of LFOM and its relationship with permafrost and environmental factors. Here, we investigated the light fraction carbon (LFC) and nitrogen (LFN) contents and stocks under meadows and wet meadows with different permafrost conditions on the southern Qinghai-Tibetan Plateau...
September 23, 2017: Science of the Total Environment
Sara Lehmann-Konera, Łukasz Franczak, Waldemar Kociuba, Danuta Szumińska, Stanisław Chmiel, Żaneta Polkowska
An increase in air temperature related to climate change results in the retreat of glaciers, the degradation of permafrost, and the expansion of glacier-free areas in the polar regions. All these processes lead to changes in the Arctic landscape. They influence the hydrochemistry of streams and rivers fed by glaciers and thawing permafrost. In this study, we examine eighty two water samples from two non-glaciated catchments with snow-permafrost regime: the Tyvjobekken Creek and the Reindeer Creek (NW Wedel-Jarlsberg Land, Spitsbergen)...
September 22, 2017: Science of the Total Environment
L F Kalenova, V P Melnikov, I M Besedin, A S Bazhin, M A Gabdulin, S S Kolyvanova
An ointment containing metabolites of Bacillus sp. microorganisms isolated from permafrost samples was applied onto the skin wound of BALB/c mice. Metabolites isolated during culturing of Bacillus sp. at 37°C produced a potent therapeutic effect and promoted wound epithelialization by 30% in comparison with the control (ointment base) and by 20% in comparison with Solcoseryl. Treatment with Bacillus sp. metabolites stimulated predominantly humoral immunity, reduced the time of wound contraction and the volume of scar tissue, and promoted complete hair recovery...
September 25, 2017: Bulletin of Experimental Biology and Medicine
Purnima Singh, Shiv M Singh, Ram N Singh, Simantini Naik, Utpal Roy, Alok Srivastava, Manfred Bölter
Permafrost soils are unique habitats in polar environment and are of great ecological relevance. The present study focuses on the characterization of bacterial communities from permafrost profiles of Svalbard, Arctic. Counts of culturable bacteria range from 1.50 × 10(3) to 2.22 × 10(5) CFU g(-1) , total bacterial numbers range from 1.14 × 10(5) to 5.52 × 10(5) cells g(-1) soil. Bacterial isolates are identified through 16S rRNA gene sequencing. Arthrobacter and Pseudomonas are the most dominant genera, and A...
September 21, 2017: Journal of Basic Microbiology
Małgorzata Szopińska, Danuta Szumińska, Robert Józef Bialik, Stanisław Chmiel, Joanna Plenzler, Żaneta Polkowska
This study provides a comprehensive analysis of the inorganic chemistry of flowing water at the western shore of Admiralty Bay. In the water samples, ions, and major and trace metals (and B) were detected and quantified. Additionally, the parameters of pH, specific electrolytic conductivity (SEC25) and total organic carbon (TOC) were determined. Moreover, multivariate data set was created and Principal Component Analysis (PCA) was performed. Generally, the water has low total content of the measured mineral constituents <100mgL(-1)...
September 17, 2017: Science of the Total Environment
Anatoli Brouchkov, Marsel Kabilov, Svetlana Filippova, Olga Baturina, Victor Rogov, Valery Galchenko, Andrey Mulyukin, Oksana Fursova, Gennady Pogorelko
Permanently frozen (approx. 3.5Ma) alluvial Neogene sediments exposed in the Aldan river valley at the Mammoth Mountain (Eastern Siberia) are unique, ancient, and poorly studied permafrost environments. So far, the structure of the indigenous bacterial community has remained unknown. Use of 16S metagenomic analysis with total DNA isolation using DNA Spin Kit for Soil (MO-Bio) and QIAamp DNA Stool Mini Kit (Qiagen) has revealed the major and minor bacterial lineages in the permafrost alluvium sediments. In sum, 61 Operational Taxonomic Units (OTUs) with 31,239 reads (Qiagen kit) and 15,404 reads (Mo-Bio kit) could be assigned to the known taxa...
September 12, 2017: Gene
Katharina Halbach, Øyvind Mikkelsen, Torunn Berg, Eiliv Steinnes
Svalbard is an important study area for investigating the long-range transport of mercury (Hg) and other trace elements to the Arctic. Few studies have focused on their concentrations in Arctic soils. With ongoing climate change leading to thawing permafrost ground the soil compartment is of increasing importance in the Arctic. In this study, elemental composition and soil organic matter (SOM) content of surface and mineral soils in Svalbard are presented. The aim is to provide new data on soils in the Arctic and to gain more knowledge about the role of the soil in the biogeochemical cycle of mercury (Hg)...
September 7, 2017: Chemosphere
Shan Dou, Nate Lindsey, Anna M Wagner, Thomas M Daley, Barry Freifeld, Michelle Robertson, John Peterson, Craig Ulrich, Eileen R Martin, Jonathan B Ajo-Franklin
Ambient-noise-based seismic monitoring of the near surface often has limited spatiotemporal resolutions because dense seismic arrays are rarely sufficiently affordable for such applications. In recent years, however, distributed acoustic sensing (DAS) techniques have emerged to transform telecommunication fiber-optic cables into dense seismic arrays that are cost effective. With DAS enabling both high sensor counts ("large N") and long-term operations ("large T"), time-lapse imaging of shear-wave velocity (V S ) structures is now possible by combining ambient noise interferometry and multichannel analysis of surface waves (MASW)...
September 14, 2017: Scientific Reports
Xiaoqing Peng, Cuicui Mu
Soil thermal and hydraulic regimes are critical factors influencing terrestrial processes in cold regions. Collection of field data from frozen ground has occurred at point scales, but limited data exist that characterize changes of soil thermal and hydraulic regimes at the scale of the whole Heihe River Basin. This study uses a long-term regional climate model coupled with land surface model to investigate the soil thermal and hydraulic regime changes at a large spatial scale. It also explores potential factors, including the climate and non-climate factors...
September 2, 2017: Environmental Monitoring and Assessment
Vasilii V Petrenko, Andrew M Smith, Hinrich Schaefer, Katja Riedel, Edward Brook, Daniel Baggenstos, Christina Harth, Quan Hua, Christo Buizert, Adrian Schilt, Xavier Fain, Logan Mitchell, Thomas Bauska, Anais Orsi, Ray F Weiss, Jeffrey P Severinghaus
Methane (CH4) is a powerful greenhouse gas and plays a key part in global atmospheric chemistry. Natural geological emissions (fossil methane vented naturally from marine and terrestrial seeps and mud volcanoes) are thought to contribute around 52 teragrams of methane per year to the global methane source, about 10 per cent of the total, but both bottom-up methods (measuring emissions) and top-down approaches (measuring atmospheric mole fractions and isotopes) for constraining these geological emissions have been associated with large uncertainties...
August 23, 2017: Nature
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