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https://www.readbyqxmd.com/read/28630484/simulated-responses-of-permafrost-distribution-to-climate-change-on-the-qinghai-tibet-plateau
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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...
May 30, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28552976/aged-dissolved-organic-carbon-exported-from-rivers-of-the-tibetan-plateau
#7
Bin Qu, Mika Sillanpää, Chaoliu Li, Shichang Kang, Aron Stubbins, Fangping Yan, Kelly Sue Aho, Feng Zhou, Peter A Raymond
The role played by river networks in regional and global carbon cycle is receiving increasing attention. Despite the potential of radiocarbon measurements (14C) to elucidate sources and cycling of different riverine carbon pools, there remain large regions such as the climate-sensitive Tibetan Plateau for which no data are available. Here we provide new 14C data on dissolved organic carbon (DOC) from three large Asian rivers (the Yellow, Yangtze and Yarlung Tsangpo Rivers) running on the Tibetan Plateau and present the carbon transportation pattern in rivers of the plateau versus other river system in the world...
2017: PloS One
https://www.readbyqxmd.com/read/28547813/salix-arctica-changes-root-distribution-and-nutrient-uptake-in-response-to-subsurface-nutrients-in-high-arctic-deserts
#8
Amanda L Guy, Sarah P Hardy, Steven D Mamet, Mitsuaki Ota, Eric G Lamb, Steven D Siciliano
Moisture is critical for plant success in polar deserts but not by the obvious pathway of reduced water stress. We hypothesized that an indirect, nutrient-linked, pathway resulting from unique water/frozen soil interactions in polar deserts creates nutrient-rich patches critical for plant growth. These nutrient-rich patches (diapirs) form deep in high arctic polar deserts soils from water accumulating at the permafrost freezing front and ultimately rising into the upper soil horizons through cryoturbated convective landforms (frost boils)...
May 26, 2017: Ecology
https://www.readbyqxmd.com/read/28542394/incorporating-public-priorities-in-the-ocean-health-index-canada-as-a-case-study
#9
Rémi M Daigle, Philippe Archambault, Benjamin S Halpern, Julia S Stewart Lowndes, Isabelle M Côté
The Ocean Health Index (OHI) is a framework to assess ocean health by considering many benefits (called 'goals') provided by the ocean provides to humans, such as food provision, tourism opportunities, and coastal protection. The OHI framework can be used to assess marine areas at global or regional scales, but how various OHI goals should be weighted to reflect priorities at those scales remains unclear. In this study, we adapted the framework in two ways for application to Canada as a case study. First, we customized the OHI goals to create a national Canadian Ocean Health Index (COHI)...
2017: PloS One
https://www.readbyqxmd.com/read/28526845/chemical-structure-of-the-lipid-a-component-of-pseudomonas-sp-strain-pamc-28618-from-thawing-permafrost-in-relation-to-pathogenicity
#10
Han-Gyu Park, Ganesan Sathiyanarayanan, Cheol-Hwan Hwang, Da-Hee Ann, Jung-Ho Kim, Geul Bang, Kyoung-Soon Jang, Hee Wook Ryu, Yoo Kyung Lee, Yung-Hun Yang, Yun-Gon Kim
Climate change causes permafrost thawing, and we are confronted with the unpredictable risk of newly discovered permafrost microbes that have disease-causing capabilities. Here, we first characterized the detailed chemical structure of the lipid A moiety from a Pseudomonas species that was isolated from thawing arctic permafrost using MALDI-based mass spectrometric approaches (i.e., MALDI-TOF MS and MALDI-QIT-TOF MS(n)). The MALDI multi-stage mass spectrometry (MS) analysis of lipid A extracted from the Pseudomonas sp...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28520473/a-new-method-and-mass-spectrometric-instrument-for-extraterrestrial-microbial-life-detection-using-the-elemental-composition-analyses-of-martian-regolith-and-permafrost-ice
#11
G G Managadze, A A Safronova, K A Luchnikov, E A Vorobyova, N S Duxbury, P Wurz, N G Managadze, A E Chumikov, R Kh Khamizov
We propose a new technique for the detection of microorganisms by elemental composition analyses of a sample extracted from regolith, permafrost, and ice of extraterrestrial bodies. We also describe the design of the ABIMAS instrument, which consists of the onboard time-of-flight laser mass-reflectron (TOF LMR) and the sample preparation unit (SPU) for biomass extraction. This instrument was initially approved to fly on board the ExoMars 2020 lander mission. The instrument can be used to analyze the elemental composition of possible extraterrestrial microbial communities and compare it to that of terrestrial microorganisms...
May 2017: Astrobiology
https://www.readbyqxmd.com/read/28510126/dehydrin-stress-proteins-in-pinus-sylvestris-l-needles-under-conditions-of-extreme-climate-of-yakutia
#12
T D Tatarinova, A A Perk, V V Bubyakina, I V Vasilieva, A G Ponomarev, T C Maximov
This is the first study to investigate stress proteins dehydrins with the use of specific antibodies in the Scots pine (Pinus sylvestris L.) needles and their changes in the annual cycle under extreme climate of Yakutia. No pronounced polymorphism of major dehydrins (14-15 and 66 kDa) has been found during the winter dormancy period of P. sylvestris. A clear correlation between the seasonal variations in dehydrins and changes in the water content in needles was revealed. Consistently high levels of dehydrins was retained throughout the period of low negative temperatures...
March 2017: Doklady. Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28500038/enrichment-and-physiological-characterization-of-a-cold-adapted-nitrite-oxidizer-nitrotoga-sp-from-eelgrass-sediments
#13
Kento Ishii, Hirotsugu Fujitani, Kentaro Soh, Tatsunori Nakagawa, Reiji Takahashi, Satoshi Tsuneda
Nitrite-oxidizing bacteria (NOB) are responsible for the second step of nitrification in natural and engineered ecosystems. The recently discovered genus Nitrotoga belongs to the Betaproteobacteria and has potentially high environmental importance. Although environmental clones affiliated with Nitrotoga are widely distributed, the limited number of cultivated Nitrotoga results in poor understanding of their ecophysiological features. In this study, we successfully enriched the non-marine cold-adapted Nitrotoga sp...
May 12, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28493191/distribution-and-variation-of-mercury-in-frozen-soils-of-a-high-altitude-permafrost-region-on-the-northeastern-margin-of-the-tibetan-plateau
#14
Shiwei Sun, Shichang Kang, Jie Huang, Shengyun Chen, Qianggong Zhang, Junming Guo, Wenjie Liu, Bigyan Neupane, Dahe Qin
The Tibetan Plateau (TP) is home to the largest permafrost bodies at low- and mid-latitudes, yet little is known about the distribution and variation of mercury (Hg) in frozen soil of the permafrost regions. In this study, extensive soil sampling campaigns were carried out in 23 soil pits from 12 plots in a high-altitude permafrost region of the Shule River Basin, northeastern TP. Hg distribution, variation, and their dependences on soil properties were analyzed. The results have revealed that total Hg (THg) concentrations were low ranging from 6...
June 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28486678/the-paleosymbiosis-hypothesis-host-plants-can-be-colonised-by-root-symbionts-that-have-been-inactive-for-centuries-to-millenia
#15
Jason Pither, Brian J Pickles
Paleoecologists have speculated that post-glacial migration of tree species could have been facilitated by mycorrhizal symbionts surviving glaciation as resistant propagules belowground. The general premise of this idea, which we call the 'paleosymbiosis hypothesis', is that host plants can access and be colonised by fungal root symbionts that have been inactive for millennia. Here, we explore the plausibility of this hypothesis by synthesising relevant findings from a diverse literature. For example, the paleoecology literature provided evidence of modern roots penetrating paleosols containing ancient (>6000 years) fungal propagules, though these were of unknown condition...
June 1, 2017: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/28484237/no-protection-of-permafrost-due-to-desertification-on-the-qinghai-tibet-plateau
#16
Qingbai Wu, Wenbing Yu, Huijun Jin
Desertification of tundra regions may form an escalating cycle with permafrost degradation where more permafrost thaw leads to continued desertification. This traditional viewpoint has been challenged in recent reports that state desertification protects the underlying permafrost. However, our measurements of soil temperature from nine sites in the Honglianghe River Basin, interior Qinghai-Tibet Plateau, show that desertification can degrade permafrost. If one compares the permafrost temperatures at sites with thin sand covers (e...
May 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28484018/enhanced-co2-uptake-at-a-shallow-arctic-ocean-seep-field-overwhelms-the-positive-warming-potential-of-emitted-methane
#17
John W Pohlman, Jens Greinert, Carolyn Ruppel, Anna Silyakova, Lisa Vielstädte, Michael Casso, Jürgen Mienert, Stefan Bünz
Continued warming of the Arctic Ocean in coming decades is projected to trigger the release of teragrams (1 Tg = 10(6) tons) of methane from thawing subsea permafrost on shallow continental shelves and dissociation of methane hydrate on upper continental slopes. On the shallow shelves (<100 m water depth), methane released from the seafloor may reach the atmosphere and potentially amplify global warming. On the other hand, biological uptake of carbon dioxide (CO2) has the potential to offset the positive warming potential of emitted methane, a process that has not received detailed consideration for these settings...
May 23, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28465527/elasticity-and-stability-of-clathrate-hydrate-role-of-guest-molecule-motions
#18
Jihui Jia, Yunfeng Liang, Takeshi Tsuji, Sumihiko Murata, Toshifumi Matsuoka
Molecular dynamic simulations were performed to determine the elastic constants of carbon dioxide (CO2) and methane (CH4) hydrates at one hundred pressure-temperature data points, respectively. The conditions represent marine sediments and permafrost zones where gas hydrates occur. The shear modulus and Young's modulus of the CO2 hydrate increase anomalously with increasing temperature, whereas those of the CH4 hydrate decrease regularly with increase in temperature. We ascribe this anomaly to the kinetic behavior of the linear CO2 molecule, especially those in the small cages...
May 2, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28464494/high-arctic-summer-warming-tracked-by-increased-cassiope-tetragona-growth-in-the-world-s-northernmost-polar-desert
#19
Stef Weijers, Agata Buchwal, Daan Blok, Jörg Löffler, Bo Elberling
Rapid climate warming has resulted in shrub expansion, mainly of erect deciduous shrubs in the Low Arctic, but the more extreme, sparsely vegetated, cold and dry High Arctic, is generally considered to remain resistant to such shrub expansion in the next decades. Dwarf shrub dendrochronology may reveal climatological causes of past changes in growth, but is hindered at many High Arctic sites by short and fragmented instrumental climate records. Moreover, only few High Arctic shrub chronologies cover the recent decade of substantial warming...
May 2, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28431357/soil-organic-carbon-and-nitrogen-pools-drive-soil-c-co2-emissions-from-selected-soils-in-maritime-antarctica
#20
C V Pires, C E R G Schaefer, A K Hashigushi, A Thomazini, E I F Filho, E S Mendonça
The ongoing trend of increasing air temperatures will potentially affect soil organic matter (SOM) turnover and soil C-CO2 emissions in terrestrial ecosystems of Maritime Antarctica. The effects of SOM quality on this process remain little explored. We evaluated (i) the quantity and quality of soil organic matter and (ii) the potential of C release through CO2 emissions in lab conditions in different soil types from Maritime Antarctica. Soil samples (0-10 and 10-20cm) were collected in Keller Peninsula and the vicinity of Arctowski station, to determine the quantity and quality of organic matter and the potential to emit CO2 under different temperature scenarios (2, 5, 8 and 11°C) in lab...
April 18, 2017: Science of the Total Environment
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