Read by QxMD icon Read


Liming Tian, Lin Zhao, Xiaodong Wu, Hongbing Fang, Yonghua Zhao, Guojie Hu, Guangyang Yue, Yu Sheng, Jichun Wu, Ji Chen, Zhiwei Wang, Wangping Li, Defu Zou, Chien-Lu Ping, Wen Shang, Yuguo Zhao, Ganlin Zhang
Soil nutrient stoichiometry and its environmental controllers play vital roles in understanding soil-plant interaction and nutrient cycling under a changing environment, while they remain poorly understood in alpine grassland due to lack of systematic field investigations. We examined the patterns and controls of soil nutrients stoichiometry for the top 10cm soils across the Tibetan ecosystems. Soil nutrient stoichiometry varied substantially among vegetation types. Alpine swamp meadow had larger topsoil C:N, C:P, N:P, and C:K ratios compared to the alpine meadow, alpine steppe, and alpine desert...
December 4, 2017: Science of the Total Environment
Shuhong Zhang, Guangli Yang, Shugui Hou, Tingjun Zhang, Zhiguo Li, Feng Liang
Antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) can be identified with metagenomic analyses comparing relatively pristine and human-impacted environments. We collected samples from 3 different environments: glacial soil little affected by anthropogenic activity, deep permafrost dated to 5821 BP (before human antibiotics), and sediment from the Pearl River. Sulfonamides, tetracyclines, and fluoroquinolones were common in the sediment samples. Sulfonamides and tetracycline were not found in permafrost; tetracycline was also not found in glacial soil...
November 28, 2017: Environmental Pollution
Sophie Crevecoeur, Warwick F Vincent, Jérôme Comte, Alex Matveev, Connie Lovejoy
Lakes and ponds derived from thawing permafrost are strong emitters of carbon dioxide and methane to the atmosphere, but little is known about the methane oxidation processes in these waters. Here we investigated the distribution and potential activity of aerobic methanotrophic bacteria in thaw ponds in two types of eroding permafrost landscapes in subarctic Québec: peatlands and mineral soils. We hypothesized that methanotrophic community composition and potential activity differ regionally as a function of the landscape type and permafrost degradation stage, and locally as a function of depth-dependent oxygen conditions...
2017: PloS One
Kun Xiao, Changchun Zou, Zhenquan Lu, Juzhi Deng
Accurate calculation of gas hydrate saturation is an important aspect of gas hydrate resource evaluation. The effective medium theory (EMT model), the velocity model based on two-phase medium theory (TPT model), and the two component laminated media model (TCLM model), are adopted to investigate the characteristics of acoustic velocity and gas hydrate saturation of pore- and fracture-filling reservoirs in the Qilian Mountain permafrost, China. The compressional wave (P-wave) velocity simulated by the EMT model is more consistent with actual log data than the TPT model in the pore-filling reservoir...
November 24, 2017: Scientific Reports
Boris P Ilyashuk, Elena A Ilyashuk, Roland Psenner, Richard Tessadri, Karin A Koinig
A global warming-induced transition from glacial to periglacial processes has been identified in mountainous regions around the world. Degrading permafrost in pristine periglacial environments can produce acid rock drainage (ARD) and cause severe ecological damage in areas underlain by sulfide-bearing bedrock. Limnological and paleolimnological approaches were used to assess and compare ARDs generated by rock glaciers, a typical landform of the mountain permafrost domain, and their effects on alpine headwater lakes with similar morphometric features and underlying bedrock geology, but characterized by different intensities of frost action in their catchments during the year...
November 15, 2017: Global Change Biology
Yuanyuan Wang, Yongqiang Zhang, Francis H S Chiew, Tim R McVicar, Lu Zhang, Hongxia Li, Guanghua Qin
As the "Asian Water Tower", the Tibetan Plateau (TP) provides water resources for more than 1.4 billion people, but suffers from climatic and environmental changes, followed by the changes in water balance components. We used state-of-the-art satellite-based products to estimate spatial and temporal variations and trends in annual precipitation, evapotranspiration and total water storage change across eastern TP, which were then used to reconstruct an annual runoff variability series for 2003-2014. The basin-scale reconstructed streamflow variability matched well with gauge observations for five large rivers...
November 13, 2017: Scientific Reports
M Oliva, P Pereira, D Antoniades
No abstract text is available yet for this article.
November 8, 2017: Science of the Total Environment
Qian Cui, Changchun Song, Xianwei Wang, Fuxi Shi, Xueyang Yu, Wenwen Tan
Climate warming is expected to increasingly influence boreal peatlands and alter their greenhouse gases emissions. However, the effects of warming on N2O fluxes and the N2O budgets were ignored in boreal peatlands. Therefore, in a boreal peatland of permafrost zone in Northeast China, a simulated warming experiment was conducted to investigate the effects of warming on N2O fluxes in Betula. Fruticosa community (B. Fruticosa) and Ledum. palustre community (L. palustre) during the growing seasons from 2013 to 2015...
November 8, 2017: Science of the Total Environment
Þorsteinn Sæmundsson, Costanza Morino, Jón Kristinn Helgason, Susan J Conway, Halldór G Pétursson
On the 20th September 2012, a large debris slide occurred in the Móafellshyrna Mountain in the Tröllaskagi peninsula, central north Iceland. Our work describes and discusses the relative importance of the three factors that may have contributed to the failure of the slope: intense precipitation, earthquake activity and thawing of ground ice. We use data from weather stations, seismometers, witness reports and field observations to examine these factors. The slide initiated after an unusually warm and dry summer followed by a month of heavy precipitation...
October 30, 2017: Science of the Total Environment
Dongliang Luo, Huijun Jin, Qingbai Wu, Victor F Bense, Ruixia He, Qiang Ma, Shuhui Gao, Xiaoying Jin, Lanzhi Lü
Ecology, hydrology, and natural resources in the source areas of the Yangtze and Yellow rivers (SAYYR) are closely linked to interactions between climate and permafrost. However, a comprehensive study of the interactions is currently hampered by sparsely- and unevenly-distributed monitoring sites and limited field investigations. In this study, the thermal regime of warm-dry permafrost in the SAYYR was systematically analyzed based on extensive data collected during 2010-2016 of air temperature (Ta), ground surface temperature (GST) and ground temperature across a range of areas with contrasting land-surface characteristics...
October 29, 2017: Science of the Total Environment
Marco Voltolini, Abdelmoula Haboub, Shan Dou, Tae Hyuk Kwon, Alastair A MacDowell, Dilworth Y Parkinson, Jonathan Ajo-Franklin
Continuous improvements at X-ray imaging beamlines at synchrotron light sources have made dynamic synchrotron X-ray micro-computed tomography (SXR-µCT) experiments more routinely available to users, with a rapid increase in demand given its tremendous potential in very diverse areas. In this work a survey of five different four-dimensional SXR-µCT experiments is presented, examining five different parameters linked to the evolution of the investigated system, and tackling problems in different areas in earth sciences...
November 1, 2017: Journal of Synchrotron Radiation
Manoj Kumar, Jan Dirk van Elsas, Riitta Nissinen
Arctic and alpine biomes are most often strongly nitrogen-limited, and hence biological nitrogen fixation is a strong driver of these ecosystems. Both biomes are characterized by low temperatures and short growing seasons, but they differ in seasonality of solar radiation and in soil water balance due to underlying permafrost in the Arctic. Arcto-alpine plant species are well-adapted to the low temperatures that prevail in their habitats, and plant growth is mainly limited by the availability of nutrients, in particular nitrogen, due to slow mineralization...
2017: Frontiers in Microbiology
Andreas Kellerer-Pirklbauer, Viktor Kaufmann
Glaciers and permafrost are strongly linked to each other in mid-latitude mountain regions particularly with polythermal glaciers. This linkage is not only climatically defined but also in terms of geomorphic and glaciological processes. We studied two adjacent cirques located in the Central Austria. We focussed on the deglaciation since the Little Ice Age (LIA) maximum (c.1850CE) and its relevance for permafrost and rock glacier evolution since then. One cirque is occupied by a glacier remnant whereas the second one is occupied by an active rock glacier which was partly overridden by a glacier during the LIA...
October 20, 2017: Science of the Total Environment
Danuta Szumińska, Małgorzata Szopińska, Sara Lehmann-Konera, Łukasz Franczak, Waldemar Kociuba, Stanisław Chmiel, Paweł Kalinowski, Żaneta Polkowska
Climate changes observed in the Arctic (e.g. permafrost degradation, glacier retreat) may have significant influence on sensitive polar wetlands. The main objectives of this paper are defining chemical features of water within six small arctic lakes located in Bellsund (Svalbard) in the area of continuous permafrost occurrence. The unique environmental conditions of the study area offer an opportunity to observe phenomena influencing water chemistry, such as: chemical weathering, permafrost thawing, marine aerosols, atmospheric deposition and biological inputs...
October 17, 2017: Science of the Total Environment
K E Roberts, S F Lamoureux, T K Kyser, D C G Muir, M J Lafrenière, D Iqaluk, A J Pieńkowski, A Normandeau
Permafrost exerts an important control over hydrological processes in Arctic landscapes and lakes. Recent warming and summer precipitation has the potential to alter water availability and quality in this environment through thermal perturbation of near surface permafrost and increased mobility of previously frozen solutes to Arctic freshwaters. We present a unique thirteen-year record (2003-16) of the physiochemical properties of two High Arctic lakes and show that the concentration of major ions, especially SO4(2-), has rapidly increased up to 500% since 2008...
October 16, 2017: Scientific Reports
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...
February 15, 2018: 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...
November 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
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"