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https://www.readbyqxmd.com/read/28515896/a-worldwide-phylogeography-of-the-whiteworm-lichens-thamnolia-reveals-three-lineages-with-distinct-habitats-and-evolutionary-histories
#1
Ioana Onuţ-Brännström, Leif Tibell, Hanna Johannesson
Thamnolia is a lichenized fungus with an extremely wide distribution, being encountered in arctic and alpine environments in most continents. In this study, we used molecular markers to investigate the population structure of the fungal symbiont and the associated photosynthetic partner of Thamnolia. By analyzing molecular, morphological, and chemical variation among 253 specimens covering the species distribution range, we revealed the existence of three mycobiont lineages. One lineage (Lineage A) is confined to the tundra region of Siberia and the Aleutian Islands, a second (Lineage B) is found in the high alpine region of the Alps and the Carpathians Mountains, and a third (Lineage C) has a worldwide distribution and covers both the aforementioned ecosystems...
May 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28508037/arctic-greening-from-warming-promotes-declines-in-caribou-populations
#2
Per Fauchald, Taejin Park, Hans Tømmervik, Ranga Myneni, Vera Helene Hausner
The migratory tundra caribou herds in North America follow decadal population cycles, and browsing from abundant caribou could be expected to counteract the current climate-driven expansion of shrubs in the circumpolar tundra biome. We demonstrate that the sea ice cover in the Arctic Ocean has provided a strong signal for climate-induced changes on the adjacent caribou summer ranges, outperforming other climate indices in explaining the caribou-plant dynamics. We found no evidence of a negative effect of caribou abundance on vegetation biomass...
April 2017: Science Advances
https://www.readbyqxmd.com/read/28488798/a-comparison-of-sedimentary-dna-and-pollen-from-lake-sediments-in-recording-vegetation-composition-at-the-siberian-treeline
#3
Bastian Niemeyer, Laura S Epp, Kathleen R Stoof-Leichsenring, Luidmila A Pestryakova, Ulrike Herzschuh
Reliable information on past and present vegetation is important to project future changes, especially for rapidly transitioning areas such as the boreal treeline. To study past vegetation, pollen analysis is common, while current vegetation is usually assessed by field surveys. Application of detailed sedimentary DNA (sedDNA) records has the potential to enhance our understanding of vegetation changes, but studies systematically investigating the power of this proxy are rare to date. This study compares sedDNA metabarcoding and pollen records from surface sediments of 31 lakes along a north-south gradient of increasing forest cover in northern Siberia (Taymyr peninsula) with data from field surveys in the surroundings of the lakes...
May 10, 2017: Molecular Ecology Resources
https://www.readbyqxmd.com/read/28488280/open-tundra-persist-but-arctic-features-decline-vegetation-changes-in-the-warming-fennoscandian-tundra
#4
Katariina E M Vuorinen, Lauri Oksanen, Tarja Oksanen, Anni Pyykönen, Johan Olofsson, Risto Virtanen
In the forest-tundra ecotone of the North Fennoscandian inland, summer and winter temperatures have increased by two to three centigrades since 1965, which is expected to result in major vegetation changes. To document the expected expansion of woodlands and scrublands and its impact on the arctic vegetation, we repeated a vegetation transect study conducted in 1976 in the Darju, spanning from woodland to a summit, 200 m above the tree line. Contrary to our expectations, tree line movement was not detected, and there was no increase in willows or shrubby mountain birches, either...
May 10, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28484237/no-protection-of-permafrost-due-to-desertification-on-the-qinghai-tibet-plateau
#5
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/28484001/carbon-dioxide-sources-from-alaska-driven-by-increasing-early-winter-respiration-from-arctic-tundra
#6
Róisín Commane, Jakob Lindaas, Joshua Benmergui, Kristina A Luus, Rachel Y-W Chang, Bruce C Daube, Eugénie S Euskirchen, John M Henderson, Anna Karion, John B Miller, Scot M Miller, Nicholas C Parazoo, James T Randerson, Colm Sweeney, Pieter Tans, Kirk Thoning, Sander Veraverbeke, Charles E Miller, Steven C Wofsy
High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012-2014. We find that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December)...
May 8, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28476175/biochemical-and-proteomics-analyses-of-antioxidant-enzymes-reveal-the-potential-stress-tolerance-in-rhododendron-chrysanthum-pall
#7
Xiaofu Zhou, Silin Chen, Hui Wu, Yi Yang, Hongwei Xu
BACKGROUND: Rhododendron chrysanthum Pall., an endangered species with significant ornamental and medicinal value, is endemic to the Changbai Mountain of China and can also serve as a significant plant resource for investigating the stress tolerance in plants. Proteomics is an effective analytical tool that provides significant information about plant metabolism and gene expression. However, no proteomics data have been reported for R. chrysanthum previously. In alpine tundra, the abiotic stress will lead to a severe over-accumulation of reactive oxygen species (ROS)...
May 3, 2017: Biology Direct
https://www.readbyqxmd.com/read/28475233/dissimilar-responses-of-larch-stands-in-northern-siberia-to-increasing-temperatures-a-field-and-simulation-based-study
#8
Mareike Wieczorek, Stefan Kruse, Laura S Epp, Alexei Kolmogorov, Anatoly N Nikolaev, Ingo Heinrich, Florian Jeltsch, Lyudmila A Pestryakova, Romy Zibulski, Ulrike Herzschuh
Arctic and alpine treelines worldwide differ in their reactions to climate change. A northward advance of or densification within the treeline ecotone will likely influence climate-vegetation feedback mechanisms. In our study, which was conducted in the Taimyr Depression in the North Siberian Lowlands, w present a combined field- and model-based approach helping us to better understand the population processes involved in the responses of the whole treeline ecotone, spanning from closed forest to single-tree tundra, to climate warming...
May 5, 2017: Ecology
https://www.readbyqxmd.com/read/28438213/cervid-herpesvirus-2-and-not-moraxella-bovoculi-caused-keratoconjunctivitis-in-experimentally-inoculated-semi-domesticated-eurasian-tundra-reindeer
#9
Morten Tryland, Javier Sánchez Romano, Nina Marcin, Ingebjørg Helena Nymo, Terje Domaas Josefsen, Karen Kristine Sørensen, Torill Mørk
BACKGROUND: Infectious keratoconjunctivitis (IKC) is a transmissible disease in semi-domesticated Eurasian reindeer (Rangifer tarandus tarandus). It is regarded as multifactorial and a single causative pathogen has not yet been identified. From clinical outbreaks we have previously identified Cervid herpesvirus 2 (CvHV2) and Moraxella bovoculi as candidates for experimental investigations. Eighteen reindeer were inoculated in the right eye with CvHV2 (n = 5), M. bovoculi (n = 5), CvHV2 and M...
April 24, 2017: Acta Veterinaria Scandinavica
https://www.readbyqxmd.com/read/28432859/the-impact-of-global-climate-change-on-the-spread-of-parasitic-nematodes
#10
Anna Okulewicz
Climate changes may influence the frequency, intensity and geographical distribution of parasites, directly affecting their dispersive stages in the environment (eggs, larvae) and, indirectly, the larvae living mainly in invertebrate intermediate hosts. In biologically diverse nematodes climate warming contributes to the increase in the range of distribution, colonization of new hosts and modification of their development cycles. This is particularly acute in the Arctic and pertains, for instance, to nematodes Ostertagia gruehneri and Setaria tundra parasitizing reindeer Rangifer tarandus and Umingmakstrongylus pallikuukensis in musk oxen (Ovibos moschatus)...
2017: Annals of Parasitology
https://www.readbyqxmd.com/read/28414338/open-path-spectroscopic-methane-detection-using-a-broadband-monolithic-distributed-feedback-quantum-cascade-laser-array
#11
Anna P M Michel, Jason Kapit, Mark F Witinski, Romain Blanchard
Methane is a powerful greenhouse gas that has both natural and anthropogenic sources. The ability to measure methane using an integrated path length approach such as an open/long-path length sensor would be beneficial in several environments for examining anthropogenic and natural sources, including tundra landscapes, rivers, lakes, landfills, estuaries, fracking sites, pipelines, and agricultural sites. Here a broadband monolithic distributed feedback-quantum cascade laser array was utilized as the source for an open-path methane sensor...
April 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/28407324/changes-in-nutrient-concentrations-of-leaves-and-roots-in-response-to-global-change-factors
#12
Jordi Sardans, Oriol Grau, Han Y H Chen, Ivan A Janssens, Philippe Ciais, Shilong Piao, Josep Peñuelas
Global Change impacts on biogeochemical cycles have been widely studied, but our understanding of whether the responses of plant elemental composition to Global Change drivers differ between above- and belowground plant organs remains incomplete. We conducted a meta-analysis of 201 reports including 1,687 observations of studies that have analyzed simultaneously N and P concentrations changes in leaves and roots in the same plants in response to drought, elevated [CO2 ], and N and P fertilization around the world, and contrasted the results within those obtained with a general database (838 reports and 14,772 observations) that analyzed the changes in N and P concentrations in leaves and/or roots of plants submitted to the commented global change drivers...
April 13, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28405308/a-gradient-of-nutrient-enrichment-reveals-nonlinear-impacts-of-fertilization-on-arctic-plant-diversity-and-ecosystem-function
#13
Case M Prager, Shahid Naeem, Natalie T Boelman, Jan U H Eitel, Heather E Greaves, Mary A Heskel, Troy S Magney, Duncan N L Menge, Lee A Vierling, Kevin L Griffin
Rapid environmental change at high latitudes is predicted to greatly alter the diversity, structure, and function of plant communities, resulting in changes in the pools and fluxes of nutrients. In Arctic tundra, increased nitrogen (N) and phosphorus (P) availability accompanying warming is known to impact plant diversity and ecosystem function; however, to date, most studies examining Arctic nutrient enrichment focus on the impact of relatively large (>25x estimated naturally occurring N enrichment) doses of nutrients on plant community composition and net primary productivity...
April 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28401610/the-potential-for-mycobiont-sharing-between-shrubs-and-seedlings-to-facilitate-tree-establishment-after-wildfire-at-alaska-arctic-treeline
#14
Rebecca E Hewitt, F Stuart Chapin, Teresa N Hollingsworth, D Lee Taylor
Root-associated fungi, particularly ectomycorrhizal fungi (EMF), are critical symbionts of all boreal tree species. Although climatically-driven increases in wildfire frequency and extent have been hypothesized to increase vegetation transitions from tundra to boreal forest, fire reduces mycorrhizal inoculum. Therefore, changes in mycobiont inoculum may potentially limit tree-seedling establishment beyond current treeline. We investigated whether ectomycorrhizal shrubs that resprout after fire support similar fungal taxa to those that associate with tree seedlings that establish naturally after fire...
April 12, 2017: Molecular Ecology
https://www.readbyqxmd.com/read/28390104/historical-and-projected-trends-in-landscape-drivers-affecting-carbon-dynamics-in-alaska
#15
Neal J Pastick, Paul Duffy, Hélène Genet, T Scott Rupp, Bruce K Wylie, Kristofer D Johnson, M Torre Jorgenson, Norman Bliss, A David McGuire, Elchin E Jafarov, Joseph F Knight
Modern climate change in Alaska has resulted in widespread thawing of permafrost, increased fire activity, and extensive changes in vegetation characteristics that have significant consequences for socioecological systems. Despite observations of the heightened sensitivity of these systems to change, there has not been a comprehensive assessment of factors that drive ecosystem changes throughout Alaska. Here we present research that improves our understanding of the main drivers of the spatiotemporal patterns of carbon dynamics using in situ observations, remote sensing data, and an array of modeling techniques...
April 8, 2017: Ecological Applications: a Publication of the Ecological Society of America
https://www.readbyqxmd.com/read/28382027/potential-for-biocontrol-of-hairy-root-disease-by-a-paenibacillus-clade
#16
Lien Bosmans, Irene De Bruijn, Saskia Gerards, Rob Moerkens, Lore Van Looveren, Lieve Wittemans, Bart Van Calenberge, Anneleen Paeleman, Stefan Van Kerckhove, René De Mot, Jef Rozenski, Hans Rediers, Jos M Raaijmakers, Bart Lievens
Rhizogenic Agrobacterium biovar 1 is the causative agent of hairy root disease (HRD) in the hydroponic cultivation of tomato and cucumber causing significant losses in marketable yield. In order to prevent and control the disease chemical disinfectants such as hydrogen peroxide or hypochlorite are generally applied to sanitize the hydroponic system and/or hydroponic solution. However, effective control of HRD sometimes requires high disinfectant doses that may have phytotoxic effects. Moreover, several of these chemicals may be converted to unwanted by-products with human health hazards...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28369368/diversity-and-spatial-temporal-distribution-of-soil-macrofauna-communities-along-elevation-in-the-changbai-mountain-china
#17
Xiuqin Yin, Lili Qiu, Yunfeng Jiang, Yeqiao Wang
The understanding of patterns of vertical variation and diversity of flora and fauna along elevational change has been well established over the past century. However, it is unclear whether there is an elevational distribution pattern for soil fauna. This study revealed the diversity and spatial-temporal distribution of soil macrofauna communities in different vegetation zones from forest to alpine tundra along elevation of the Changbai Mountain, China. The abundance, richness, and Shannon-Wiener diversity index of soil macrofauna communities were compared in four distinguished vegetation zones including the coniferous and broadleaved mixed forest zone, the coniferous forest zone, the subalpine dwarf birch (Betula ermanii) forest zone, and the alpine tundra zone...
June 1, 2017: Environmental Entomology
https://www.readbyqxmd.com/read/28324843/variations-in-pu-isotopic-composition-in-soils-from-the-spitsbergen-norway-three-potential-pollution-sources-of-the-arctic-region
#18
E Łokas, R Anczkiewicz, R Kierepko, J W Mietelski
Although the polar regions have not been industrialised, numerous contaminants originating from human activity are detectable in the Arctic environment. This study reports evidence of (240)Pu/(239)Pu atomic ratios in the tundra and initial soils from different parts of west and central Spitsbergen and recognizes possible environmental inputs of non-global fallout Pu. The average atomic ratio of (240)Pu/(239)Pu equal to 0.179 (ranging between 0.129 and 0.201) in tundra soils are comparable to the characteristic ratio for global fallout (0...
March 18, 2017: Chemosphere
https://www.readbyqxmd.com/read/28317109/what-if-plant-functional-types-conceal-species-specific-responses-to-environment-study-on-arctic-shrub-communities
#19
Patrick Saccone, Kristiina Hoikka, Risto Virtanen
Plant functional types (PFT) are increasingly used to outline biome-scale plant-environment relationship and predict global change effects on community structure. However, the potentials and limitations of the PFT approach have to be tested as they can be less sensitive than trait-based or species-level approaches. Here, we compare the responses of deciduous-evergreen shrub PFTs and species to gradual snow-related environmental conditions by also considering effects of aboveground architectural traits and neighboring shrubs...
March 19, 2017: Ecology
https://www.readbyqxmd.com/read/28295022/impacts-of-twenty-years-of-experimental-warming-on-soil-carbon-nitrogen-moisture-and-soil-mites-across-alpine-subarctic-tundra-communities
#20
Juha M Alatalo, Annika K Jägerbrand, Jaanis Juhanson, Anders Michelsen, Peter Ľuptáčik
High-altitude and alpine areas are predicted to experience rapid and substantial increases in future temperature, which may have serious impacts on soil carbon, nutrient and soil fauna. Here we report the impact of 20 years of experimental warming on soil properties and soil mites in three contrasting plant communities in alpine/subarctic Sweden. Long-term warming decreased juvenile oribatid mite density, but had no effect on adult oribatids density, total mite density, any major mite group or the most common species...
March 15, 2017: Scientific Reports
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