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https://www.readbyqxmd.com/read/28079308/greater-temperature-sensitivity-of-plant-phenology-at-colder-sites-implications-for-convergence-across-northern-latitudes
#1
Janet Prevéy, Mark Vellend, Nadja Rüger, Robert D Hollister, Anne D Bjorkman, Isla H Myers-Smith, Sarah C Elmendorf, Karin Clark, Elisabeth J Cooper, Bo Elberling, Anna Maria Fosaa, Gregory H R Henry, Toke T Høye, Ingibjörg Svala Jónsdóttir, Kari Klanderud, Esther Lévesque, Marguerite Mauritz, Ulf Molau, Susan M Natali, Steven F Oberbauer, Zoe A Panchen, Eric Post, Sabine B Rumpf, Niels M Schmidt, Ted Schuur, Phillip R Semenchuk, Tiffany Troxler, Jeffrey M Welker, Christian Rixen
Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher-latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up to 20 years of phenology data for 47 tundra plant species at 18 high-latitude sites along a climatic gradient. Across all species, the timing of leaf emergence and flowering were more sensitive to a given increase in summer temperature at colder than warmer high-latitude locations...
January 11, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28063181/climatic-warming-strengthens-a-positive-feedback-between-alpine-shrubs-and-fire
#2
James S Camac, Richard J Williams, Carl-Henrik Wahren, Ary A Hoffmann, Peter A Vesk
Climate change is expected to increase fire activity and woody plant encroachment in arctic and alpine landscapes. However, the extent to which these increases interact to affect the structure, function and composition of alpine ecosystems is largely unknown. Here we use field surveys and experimental manipulations to examine how warming and fire affect recruitment, seedling growth and seedling survival in four dominant Australian alpine shrubs. We found that fire increased establishment of shrub seedlings by as much as 33-fold...
January 7, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28062107/diurnal-evolution-of-the-temperature-sensitivity-of-co2-efflux-in-permafrost-soils-under-control-and-warm-conditions
#3
Julien Fouché, Catherine Keller, Michel Allard, Jean Paul Ambrosi
Cryosols contain ~33% of the global soil organic carbon. Cryosol warming and permafrost degradation may enhance the CO2 release to the atmosphere through the microbial decomposition. Despite the large carbon pool, the permafrost carbon feedback on the climate remains uncertain. In this study, we aimed at better understanding the diurnal evolution of the temperature sensitivity of CO2 efflux in Cryosols. A Histic Cryosol and a Turbic Cryosol were instrumented in tussock tundra ecosystems near Salluit (Nunavik, Canada)...
January 3, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28028549/ssunique-detecting-sequence-novelty-in-microbiome-surveys
#4
Michael D J Lynch, Josh D Neufeld
High-throughput sequencing of small-subunit (SSU) rRNA genes has revolutionized understanding of microbial communities and facilitated investigations into ecological dynamics at unprecedented scales. Such extensive SSU rRNA gene sequence libraries, constructed from DNA extracts of environmental or host-associated samples, often contain a substantial proportion of unclassified sequences, many representing organisms with novel taxonomy (taxonomic "blind spots") and potentially unique ecology. Indeed, these novel taxonomic lineages are associated with so-called microbial "dark matter," which is the genomic potential of these lineages...
November 2016: MSystems
https://www.readbyqxmd.com/read/27994976/diversity-taxonomic-composition-and-functional-aspects-of-fungal-communities-in-living-senesced-and-fallen-leaves-at-five-sites-across-north-america
#5
Jana M U'Ren, A Elizabeth Arnold
BACKGROUND: Fungal endophytes inhabit symptomless, living tissues of all major plant lineages to form one of earth's most prevalent groups of symbionts. Many reproduce from senesced and/or decomposing leaves and can produce extracellular leaf-degrading enzymes, blurring the line between symbiotrophy and saprotrophy. To better understand the endophyte-saprotroph continuum we compared fungal communities and functional traits of focal strains isolated from living leaves to those isolated from leaves after senescence and decomposition, with a focus on foliage of woody plants in five biogeographic provinces ranging from tundra to subtropical scrub forest...
2016: PeerJ
https://www.readbyqxmd.com/read/27974492/highly-individualistic-rates-of-plant-phenological-advance-associated-with-arctic-sea-ice-dynamics
#6
Eric Post, Jeffrey Kerby, Christian Pedersen, Heidi Steltzer
We analysed 12 years of species-specific emergence dates of plants at a Low-Arctic site near Kangerlussuaq, Greenland to investigate associations with sea ice dynamics, a potential contributor to local temperature variation in near-coastal tundra. Species displayed highly variable rates of phenological advance, from a maximum of -2.55 ± 0.17 and -2.93 ± 0.51 d yr(-1) among a graminoid and forb, respectively, to a minimum of -0.55 ± 0.19 d yr(-1) or no advance at all in the two deciduous shrub species. Monthly Arctic-wide sea ice extent was a significant predictor of emergence timing in 10 of 14 species...
December 2016: Biology Letters
https://www.readbyqxmd.com/read/27933047/diazotroph-diversity-in-the-sea-ice-melt-ponds-and-surface-waters-of-the-eurasian-basin-of-the-central-arctic-ocean
#7
Mar Fernández-Méndez, Kendra A Turk-Kubo, Pier L Buttigieg, Josephine Z Rapp, Thomas Krumpen, Jonathan P Zehr, Antje Boetius
The Eurasian basin of the Central Arctic Ocean is nitrogen limited, but little is known about the presence and role of nitrogen-fixing bacteria. Recent studies have indicated the occurrence of diazotrophs in Arctic coastal waters potentially of riverine origin. Here, we investigated the presence of diazotrophs in ice and surface waters of the Central Arctic Ocean in the summer of 2012. We identified diverse communities of putative diazotrophs through targeted analysis of the nifH gene, which encodes the iron protein of the nitrogenase enzyme...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27928986/roseomonas-arcticisoli-sp-nov-isolated-from-arctic-tundra-soil
#8
Myong Chol Kim, Songguk Rim, Sehong Pak, Lvzhi Ren, Yumin Zhang, Xulu Chang, Xuhuan Li, Chengxiang Fang, Congyi Zheng, Fang Peng
No abstract text is available yet for this article.
November 2016: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/27917060/antarctotrechus-balli-sp-n-carabidae-trechini-the-first-ground-beetle-from-antarctica
#9
Allan C Ashworth, Terry L Erwin
Fossil elytra of a small trechine carabid are reported from the Oliver Bluffs on the Beardmore Glacier at lat. 85°S. They were compared with counterparts from the extant genera Trechisibus, Tasmanorites, Oxytrechus and Pseudocnides. The fossils share some characters but are sufficiently different to be described as a new genus and species. We named the new species Antarctotrechus balli in honour of George E. Ball who made major contributions to the study of carabids through his own research and the training of students while at the University of Alberta, Edmonton, Alberta, Canada...
2016: ZooKeys
https://www.readbyqxmd.com/read/27904966/treeline-advances-and-associated-shifts-in-the-ground-vegetation-alter-fine-root-dynamics-and-mycelia-production-in-the-south-and-polar-urals
#10
Emily F Solly, Ika Djukic, Pavel A Moiseev, Nelly I Andreyashkina, Nadezhda M Devi, Hans Göransson, Valeriy S Mazepa, Stepan G Shiyatov, Marina R Trubina, Fritz H Schweingruber, Martin Wilmking, Frank Hagedorn
Climate warming is shifting the elevational boundary between forests and tundra upwards, but the related belowground responses are poorly understood. In the pristine South and Polar Urals with shifts of the treeline ecotone documented by historical photographs, we investigated fine root dynamics and production of extramatrical mycorrhizal mycelia (EMM) along four elevational transects reaching from the closed forest to the treeless tundra. In addition, we analysed elevational differences in climate and vegetation structure, and excavated trees to estimate related changes in the partitioning between below- and aboveground biomass...
November 30, 2016: Oecologia
https://www.readbyqxmd.com/read/27902716/large-scale-anthropogenic-reduction-of-forest-cover-in-last-glacial-maximum-europe
#11
Jed O Kaplan, Mirjam Pfeiffer, Jan C A Kolen, Basil A S Davis
Reconstructions of the vegetation of Europe during the Last Glacial Maximum (LGM) are an enigma. Pollen-based analyses have suggested that Europe was largely covered by steppe and tundra, and forests persisted only in small refugia. Climate-vegetation model simulations on the other hand have consistently suggested that broad areas of Europe would have been suitable for forest, even in the depths of the last glaciation. Here we reconcile models with data by demonstrating that the highly mobile groups of hunter-gatherers that inhabited Europe at the LGM could have substantially reduced forest cover through the ignition of wildfires...
2016: PloS One
https://www.readbyqxmd.com/read/27898193/modeling-long-term-changes-in-tundra-carbon-balance-following-wildfire-climate-change-and-potential-nutrient-addition
#12
Yueyang Jiang, Edward B Rastetter, Gaius R Shaver, Adrian V Rocha, Qianlai Zhuang, Bonnie L Kwiatkowski
To investigate the underlying mechanisms that control long-term recovery of tundra carbon (C) and nutrients after fire, we employed the Multiple Element Limitation (MEL) model to simulate 200-yr post-fire changes in the biogeochemistry of three sites along a burn severity gradient in response to increases in air temperature, CO2 concentration, nitrogen (N) deposition, and phosphorus (P) weathering rates. The simulations were conducted for severely burned, moderately burned, and unburned arctic tundra. Our simulations indicated that recovery of C balance after fire was mainly determined by the internal redistribution of nutrients among ecosystem components (controlled by air temperature), rather than the supply of nutrients from external sources (e...
August 4, 2016: Ecological Applications: a Publication of the Ecological Society of America
https://www.readbyqxmd.com/read/27883187/molybdenum-and-phosphorus-limitation-of-moss-associated-nitrogen-fixation-in-boreal-ecosystems
#13
Kathrin Rousk, Jefferson Degboe, Anders Michelsen, Robert Bradley, Jean-Philippe Bellenger
Biological nitrogen fixation (BNF) performed by moss-associated cyanobacteria is one of the main sources of new nitrogen (N) input in pristine, high-latitude ecosystems. Yet, the nutrients that limit BNF remain elusive. Here, we tested whether this important ecosystem function is limited by the availability of molybdenum (Mo), phosphorus (P), or both. BNF in dominant mosses was measured with the acetylene reduction assay (ARA) at different time intervals following Mo and P additions, in both laboratory microcosms with mosses from a boreal spruce forest and field plots in subarctic tundra...
November 24, 2016: New Phytologist
https://www.readbyqxmd.com/read/27881760/changes-in-composition-and-abundance-of-functional-groups-of-arctic-fungi-in-response-to-long-term-summer-warming
#14
József Geml, Tatiana A Semenova, Luis N Morgado, Jeffrey M Welker
We characterized fungal communities in dry and moist tundra and investigated the effect of long-term experimental summer warming on three aspects of functional groups of arctic fungi: richness, community composition and species abundance. Warming had profound effects on community composition, abundance, and, to a lesser extent, on richness of fungal functional groups. In addition, our data show that even within functional groups, the direction and extent of response to warming tend to be species-specific and we recommend that studies on fungal communities and their roles in nutrient cycling take into account species-level responses...
November 2016: Biology Letters
https://www.readbyqxmd.com/read/27878083/interactive-effects-between-plant-functional-types-and-soil-factors-on-tundra-species-diversity-and-community-composition
#15
Maitane Iturrate-Garcia, Michael J O'Brien, Olga Khitun, Samuel Abiven, Pascal A Niklaus, Gabriela Schaepman-Strub
Plant communities are coupled with abiotic factors, as species diversity and community composition both respond to and influence climate and soil characteristics. Interactions between vegetation and abiotic factors depend on plant functional types (PFT) as different growth forms will have differential responses to and effects on site characteristics. However, despite the importance of different PFT for community assembly and ecosystem functioning, research has mainly focused on vascular plants. Here, we established a set of observational plots in two contrasting habitats in northeastern Siberia in order to assess the relationship between species diversity and community composition with soil variables, as well as the relationship between vegetation cover and species diversity for two PFT (nonvascular and vascular)...
November 2016: Ecology and Evolution
https://www.readbyqxmd.com/read/27862698/warming-of-subarctic-tundra-increases-emissions-of-all-three-important-greenhouse-gases-carbon-dioxide-methane-and-nitrous-oxide
#16
Carolina Voigt, Richard E Lamprecht, Maija E Marushchak, Saara E Lind, Alexander Novakovskiy, Mika Aurela, Pertti J Martikainen, Christina Biasi
Rapidly rising temperatures in the Arctic might cause a greater release of greenhouse gases (GHGs) to the atmosphere. To study the effect of warming on GHG dynamics, we deployed open-top chambers in a subarctic tundra site in Northeast European Russia. We determined carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2 O) fluxes as well as the concentration of those gases, inorganic nitrogen (N) and dissolved organic carbon (DOC) along the soil profile. Studied tundra surfaces ranged from mineral to organic soils and from vegetated to unvegetated areas...
November 14, 2016: Global Change Biology
https://www.readbyqxmd.com/read/27860006/on-the-ecology-and-range-of-anopheles-beklemishevi-diptera-culicidae-with-reference-to-the-taxonomy-of-an-lewisi
#17
Yuri M Novikov
The ecological features and geographic distribution of Anopheles beklemishevi have not been studied extensively. These studies are important in connection with the validity of the 'Anopheles lewisi' taxon. The materials were collected in Russia and Kazakhstan from 1973 to 2012, and species identity was defined by cytogenetic analysis of polytene chromosomes of larvae and adult females. A total of 7,896 specimens from 34 geographic locations was included in the analysis. It was established that An. beklemishevi is distributed from the east coast of the Baltic Sea to the basin of the Lena River, and from the forest-tundra zone to the Altai and Sayan Mountain systems...
December 2016: Journal of Vector Ecology: Journal of the Society for Vector Ecology
https://www.readbyqxmd.com/read/27854567/metagenomic-evaluation-of-bacteria-from-voles
#18
Katja A Koskela, Laura Kalin-Mänttäri, Heidi Hemmilä, Teemu Smura, Paula M Kinnunen, Jukka Niemimaa, Heikki Henttonen, Simo Nikkari
Voles (Arvicolinae, Rodentia) are known carriers of zoonotic bacteria such as Bartonella spp. and Francisella tularensis. However, apart from F. tularensis, the bacterial microbiome of voles has not previously been determined in Finland and rarely elsewhere. Therefore, we studied liver samples from 61 voles using 16S ribosomal RNA gene PCR analysis, followed by Sanger sequencing. Twenty-three of these samples were also studied with tag-encoded pyrosequencing. The samples originated from 21 field voles (Microtus agrestis), 37 tundra voles (Microtus oeconomus), and 3 bank voles (Myodes glareolus)...
November 17, 2016: Vector Borne and Zoonotic Diseases
https://www.readbyqxmd.com/read/27853118/traditional-living-habits-of-the-taz-tundra-population-a-paleoparasitological-study
#19
Sergey Mikhailovich Slepchenko, Sergey Nikolaevich Ivanov, Bagashev Anatoly Nikolaevich, Tsybankov Alexander Alekseevich, Slavinsky Vyacheslav Sergeyevich
An excavation of the Vesakoyakha II-IV and Nyamboyto I burial grounds was conducted during the 2014 field season, and soil samples from intact burials dating from the 19th and 20th centuries, respectively, were analyzed to determine interactions between parasites and host/vectors. Considering the discovery of Diphyllobothrium sp. and Taenia sp. eggs in soil samples from the pelvic region, diphyllobothriasis was the most frequent helminthic infection among the Taz Nenets. The Nyamboyto Nenets mainly consumed uncooked fish, while the Vesakoyakha Nenets had a bigger variety in food choices, including reindeer meat...
October 2016: Korean Journal of Parasitology
https://www.readbyqxmd.com/read/27852939/sea-ice-rain-on-snow-and-tundra-reindeer-nomadism-in-arctic-russia
#20
Bruce C Forbes, Timo Kumpula, Nina Meschtyb, Roza Laptander, Marc Macias-Fauria, Pentti Zetterberg, Mariana Verdonen, Anna Skarin, Kwang-Yul Kim, Linette N Boisvert, Julienne C Stroeve, Annett Bartsch
Sea ice loss is accelerating in the Barents and Kara Seas (BKS). Assessing potential linkages between sea ice retreat/thinning and the region's ancient and unique social-ecological systems is a pressing task. Tundra nomadism remains a vitally important livelihood for indigenous Nenets and their large reindeer herds. Warming summer air temperatures have been linked to more frequent and sustained summer high-pressure systems over West Siberia, Russia, but not to sea ice retreat. At the same time, autumn/winter rain-on-snow (ROS) events have become more frequent and intense...
November 2016: Biology Letters
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