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Daan Blok, Samuel Faucherre, Imre Banyasz, Riikka Rinnan, Anders Michelsen, Bo Elberling
Tundra regions are projected to warm rapidly during the coming decades. The tundra biome holds the largest terrestrial carbon pool, largely contained in frozen permafrost soils. With warming, these permafrost soils may thaw and become available for microbial decomposition, potentially providing a positive feedback to global warming. Warming may directly stimulate microbial metabolism but may also indirectly stimulate organic matter turnover through increased plant productivity by soil priming from root exudates and accelerated litter turnover rates...
December 13, 2017: Global Change Biology
Marius Hauglin, Ole Martin Bollandsås, Terje Gobakken, Erik Næsset
Monitoring of forest resources through national forest inventory programmes is carried out in many countries. The expected climate changes will affect trees and forests and might cause an expansion of trees into presently treeless areas, such as above the current alpine tree line. It is therefore a need to develop methods that enable the inclusion of also these areas into monitoring programmes. Airborne laser scanning (ALS) is an established tool in operational forest inventories, and could be a viable option for monitoring tasks...
December 8, 2017: Environmental Monitoring and Assessment
Jing Tang, Alla Y Yurova, Guy Schurgers, Paul A Miller, Stefan Olin, Benjamin Smith, Matthias B Siewert, David Olefeldt, Petter Pilesjö, Anneli Poska
Tundra soils account for 50% of global stocks of soil organic carbon (SOC), and it is expected that the amplified climate warming in high latitude could cause loss of this SOC through decomposition. Decomposed SOC could become hydrologically accessible, which increase downstream dissolved organic carbon (DOC) export and subsequent carbon release to the atmosphere, constituting a positive feedback to climate warming. However, DOC export is often neglected in ecosystem models. In this paper, we incorporate processes related to DOC production, mineralization, diffusion, sorption-desorption, and leaching into a customized arctic version of the dynamic ecosystem model LPJ-GUESS in order to mechanistically model catchment DOC export, and to link this flux to other ecosystem processes...
December 4, 2017: Science of the Total Environment
Decai Gao, Lei Zhang, Jun Liu, Bo Peng, Zhenzhen Fan, Weiwei Dai, Ping Jiang, Edith Bai
Altered freeze-thaw cycle (FTC) patterns due to global climate change may affect nitrogen (N) cycling in terrestrial ecosystems. However, the general responses of soil N pools and fluxes to different FTC patterns are still poorly understood. Here, we compiled data of 1519 observations from 63 studies and conducted a meta-analysis of the responses of 17 variables involved in terrestrial N pools and fluxes to FTC. Results showed that under FTC treatment, soil NH4+ , NO3- , NO3- leaching, and N2 O emission significantly increased by 18...
December 7, 2017: Global Change Biology
Siavash Atashgahi, Max M Häggblom, Hauke Smidt
Halogenated organic compounds, also termed organohalogens, were initially considered to be of almost exclusively anthropogenic origin. However, over 5000 naturally-synthesized organohalogens are known today. This has also fuelled the hypothesis that the natural and ancient origin of organohalogens could have primed development of metabolic machineries for their degradation, especially in microorganisms. Among these, a special group of anaerobic microorganisms was discovered that could conserve energy by reducing organohalogens as terminal electron acceptor in a process termed organohalide respiration...
December 7, 2017: Environmental Microbiology
Tage Vowles, Bengt Gunnarsson, Ulf Molau, Thomas Hickler, Leif Klemedtsson, Robert G Björk
One of the most palpable effects of warming in Arctic ecosystems is shrub expansion above the tree line. However, previous studies have found that reindeer can influence plant community responses to warming and inhibit shrubification of the tundra.We revisited grazed (ambient) and ungrazed study plots (exclosures), at the southern as well as the northern limits of the Swedish alpine region, to study long-term grazing effects and vegetation changes in response to increasing temperatures between 1995 and 2011, in two vegetation types (shrub heath and mountain birch forest)...
November 2017: Journal of Ecology
Dockyu Kim, Ha Ju Park, Woo Jun Sul, Hyun Park
Although humic acids (HA) are involved in many biological processes in soils and thus their ecological importance has received much attention, the degradative pathways and corresponding catalytic genes underlying the HA degradation by bacteria remain unclear. To unveil those uncertainties, we analyzed transcriptomes extracted from Pseudomonas sp. PAMC 26793 cells time-dependently induced in the presence of HA in a lab flask. Out of 6288 genes, 299 (microarray) and 585 (RNA-seq) were up-regulated by > 2...
December 1, 2017: Folia Microbiologica
Sandra Lai, Adrien Quiles, Josie Lambourdière, Dominique Berteaux, Aude Lalis
OBJECTIVE: The arctic fox (Vulpes lagopus) is a circumpolar species inhabiting all accessible Arctic tundra habitats. The species forms a panmictic population over areas connected by sea ice, but recently, kin clustering and population differentiation were detected even in regions where sea ice was present. The purpose of this study was to examine the genetic structure of a population in the High Arctic using a robust panel of highly polymorphic microsatellites. RESULTS: We analyzed the genotypes of 210 individuals from Bylot Island, Nunavut, Canada, using 15 microsatellite loci...
December 1, 2017: BMC Research Notes
Thomas C Parker, Jianwu Tang, Mahalia B Clark, Michael M Moody, Ned Fetcher
Eriophorum vaginatum is a tussock-forming sedge that contributes significantly to the structure and primary productivity of moist acidic tussock tundra. Locally adapted populations (ecotypes) have been identified across the geographical distribution of E. vaginatum; however, little is known about how their growth and phenology differ over the course of a growing season. The growing season is short in the Arctic and therefore exerts a strong selection pressure on tundra species. This raises the hypothesis that the phenology of arctic species may be poorly adapted if the timing and length of the growing season change...
November 2017: Ecology and Evolution
Mathilde Borg Dahl, Anders Priemé, Asker Brejnrod, Peter Brusvang, Magnus Lund, Josephine Nymand, Magnus Kramshøj, Helge Ro-Poulsen, Merian Skouw Haugwitz
Future increases in temperature and cloud cover will alter plant growth and decomposition of the large carbon pools stored in Arctic soils. A better understanding of interactions between above- and belowground processes and communities of plants and microorganisms is essential for predicting Arctic ecosystem responses to climate change. We measured ecosystem CO2 fluxes during the growing season for seven years in a dwarf-shrub tundra in West Greenland manipulated with warming and shading and experiencing a natural larvae outbreak...
November 22, 2017: Scientific Reports
Fei Yao, Shan Yang, Zhirui Wang, Xue Wang, Ji Ye, Xugao Wang, Jennifer M DeBruyn, Xue Feng, Yong Jiang, Hui Li
The elevational pattern of soil microbial diversity along mountain slopes has received considerable interest over the last decade. An increasing amount of taxonomic data on soil microbial community composition along elevation gradients have been collected, however the trophic patterns and environmental drivers of elevational changes remain largely unclear. Here, we examined the distribution patterns of major soil bacterial and fungal taxa along the northern slope of Changbai Mountain, Northeast China, at five typical vegetation types located between 740 and 2,691 m above sea level...
2017: Frontiers in Microbiology
Megan L Peterson, Daniel F Doak, William F Morris
Many predictions of how climate change will impact biodiversity have focused on range shifts using species-wide climate tolerances, an approach that ignores the demographic mechanisms that enable species to attain broad geographic distributions. But these mechanisms matter, as responses to climate change could fundamentally differ depending on the contributions of life history plasticity vs local adaptation to species-wide climate tolerances. In particular, if local adaptation to climate is strong, populations across a species' range - not only those at the trailing range edge - could decline sharply with global climate change...
November 20, 2017: Global Change Biology
Kevin A Jernigan, Olga S Belichenko, Valeria B Kolosova, Darlene J Orr
BACKGROUND: This study focuses on health-related plant use among speakers of the critically endangered Naukan language (Inuit-Yupik-Unangan family) in the Russian Far East. The Naukan people were forced, in 1958, under Soviet consolidation, to move from their original settlement on Cape Dezhnev, leading to significant changes in spiritual worldview, subsistence, social structure, and language proficiency in the years that followed. Here, we focus on changes that elders report in their edible, medicinal, and spiritual uses of local plant species since their childhood...
November 17, 2017: Journal of Ethnobiology and Ethnomedicine
Claudia Colesie, Burkhard Büdel, Vaughan Hurry, T G Allan Green
The Antarctic Peninsula, a tundra biome dominated by lichens and bryophytes, is an ecozone undergoing rapid temperature shifts. Such changes may demand a high physiological plasticity of the local lichen species in order for them to maintain their role as key drivers in this pristine habitat. This study examines the response of net photosynthesis and respiration to increasing temperatures for three Antarctic lichen species with different ecological response amplitudes. We hypothesise that negative effects caused by increased temperatures can be mitigated by thermal acclimation of respiration and/or photosynthesis...
November 15, 2017: Global Change Biology
Maria V Korneykova, Galina A Evdokimova
The fungi and bacteria number, as well as the species composition of the fungi in the ground air layer in the European Arctic region of Russia, primarily in the tundra (the Rybachy Peninsula), in the subzone of the northern taiga (the Pasvik State Nature Reserve) and in the industrial areas (the Copper-Nickel Plant "Pechenganickel," the Kandalaksha Aluminum Plant) have been studied. One hundred and ninety-two atmosphere air samples of various ecosystems have been analyzed. The sample collection took place in the summer-autumn period (June, July, September, in 2012-2015) with the aspirator, precipitating microorganisms on the surface of media...
November 10, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
Paul Grogan, Tara J Zamin
Plant compensatory growth responses to herbivory are mediated by soil fertility and can have significant feedbacks that affect overall ecosystem nutrient cycling. The sedge Eriophorum vaginatum is the dominant graminoid in arctic mesic tundra, and is heavily consumed by caribou. Here, we compare the principal compensatory growth models in explaining the impact of a single episode of simulated caribou grazing at two clipping intensities on E. vaginatum total growing season shoot production, nitrogen concentrations, and nitrogen pools, over two successive years across a soil nitrogen fertilisation gradient...
November 2, 2017: Oecologia
Nicholas T Au, Tove Ryman, Allan E Rettie, Scarlett E Hopkins, Bert B Boyer, Jynene Black, Jacques Philip, Joseph Yracheta, Alison E Fohner, Morayma Reyes, Timothy A Thornton, Melissa A Austin, Kenneth E Thummel
SCOPE: We investigated the relationship between dietary vitamin K and plasma PIVKA-II concentration, a biomarker of hepatic vitamin K status, in a Yup'ik study population in southwestern Alaska. METHODS AND RESULTS: A total of 659 male and female, self-reported Yup'ik people, ≥ 14 years of age, were enrolled. Blood was collected for genotyping and plasma PIVKA-II biomarker analysis. A Yup'ik-specific dietary food frequency questionnaire was used to assess vitamin K intake...
November 2, 2017: Molecular Nutrition & Food Research
Kathleen D Klinich, Miriam A Manary, Laura A Malik, Carol A Flannagan, Jessica S Jermakian
OBJECTIVE: Investigate vehicle factors associated with child restraint tether use and misuse in pickup trucks and evaluate four labeling interventions designed to educate consumers on proper tether use. METHODS: Volunteer testing was performed with 24 subjects and four different pickup trucks. Each subject performed eight child restraint installations among the four pickups using two forward-facing restraints: a Britax Marathon G4.1 and an Evenflo Triumph. Vehicles were selected to represent four different implementations of tether anchors among pickups: plastic loop routers (Chevrolet Silverado), webbing routers (Ram), back wall anchors (Nissan Frontier), and webbing routers plus metal anchors (Toyota Tundra)...
October 30, 2017: Traffic Injury Prevention
Anna K Liljedahl, Larry D Hinzman, Douglas L Kane, Walter C Oechel, Craig E Tweedie, Donatella Zona
Difficulties in obtaining accurate precipitation measurements have limited meaningful hydrologic assessment for over a century due to performance challenges of conventional snowfall and rainfall gauges in windy environments. Here, we compare snowfall observations and bias adjusted snowfall to end-of-winter snow accumulation measurements on the ground for 16 years (1999-2014) and assess the implication of precipitation underestimation on the water balance for a low-gradient tundra wetland near Utqiagvik (formerly Barrow), Alaska (2007-2009)...
August 2017: Water Resources Research
Haibo Du, Jie Liu, Mai-He Li, Ulf Büntgen, Yue Yang, Lei Wang, Zhengfang Wu, Hong S He
Treeline responses to environmental changes describe an important phenomenon in global change research. Often conflicting results and generally too short observations are, however, still challenging our understanding of climate-induced treeline dynamics. Here, we use a state-of-the-art dendroecological approach to reconstruct long-term changes in the position of the alpine treeline in relation to air temperature at two sides in the Changbai Mountains in northeast China. Over the past 160 years, the treeline increased by around 80 m, a process that can be divided into three phases of different rates and drives...
October 28, 2017: Global Change Biology
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