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https://www.readbyqxmd.com/read/27924914/arctic-lakes-show-strong-decadal-trend-in-earlier-spring-ice-out
#1
Tereza Šmejkalová, Mary E Edwards, Jadunandan Dash
The timing of the seasonal freeze-thaw cycle of arctic lakes affects ecological processes and land-atmosphere energy fluxes. We carried out detailed ice-phenology mapping of arctic lakes, based on daily surface-reflectance time series for 2000-2013 from MODIS at 250 m spatial resolution. We used over 13,300 lakes, area >1 km(2), in five study areas distributed evenly across the circumpolar Arctic - the first such phenological dataset. All areas showed significant trends towards an earlier break-up, stronger than previously reported...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27922097/arctic-megaslide-at-presumed-rest
#2
Wolfram H Geissler, A Catalina Gebhardt, Felix Gross, Jutta Wollenburg, Laura Jensen, Mechita C Schmidt-Aursch, Sebastian Krastel, Judith Elger, Giacomo Osti
Slope failure like in the Hinlopen/Yermak Megaslide is one of the major geohazards in a changing Arctic environment. We analysed hydroacoustic and 2D high-resolution seismic data from the apparently intact continental slope immediately north of the Hinlopen/Yermak Megaslide for signs of past and future instabilities. Our new bathymetry and seismic data show clear evidence for incipient slope instability. Minor slide deposits and an internally-deformed sedimentary layer near the base of the gas hydrate stability zone imply an incomplete failure event, most probably about 30000 years ago, contemporaneous to or shortly after the Hinlopen/Yermak Megaslide...
December 6, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27919923/clonality-increases-with-snow-depth-in-the-arctic-dwarf-shrub-empetrum-hermaphroditum
#3
Miriam J Bienau, R Lutz Eckstein, Annette Otte, Walter Durka
PREMISE OF THE STUDY: Vegetative reproduction and spread through clonal growth plays an important role in arctic-alpine ecosystems with short cool growing seasons. Local variation in winter snow accumulation leads to discrete habitat types that may provide divergent conditions for sexual and vegetative reproduction. Therefore, we studied variation in clonal structure of a dominant, evergreen, dwarf shrub (Empetrum nigrum s.l. with the two taxa E. nigrum L. s.s. and E. hermaphroditum Hagerup) along a snow cover gradient and compared clonal diversity and spatial genetic structure between habitats...
December 5, 2016: American Journal of Botany
https://www.readbyqxmd.com/read/27919712/extracts-from-two-ubiquitous-mediterranean-plants-ameliorate-cellular-and-animal-models-of-neurodegenerative-proteinopathies
#4
Michelle Briffa, Stephanie Ghio, Johanna Neuner, Alison J Gauci, Rebecca Cacciottolo, Christelle Marchal, Mario Caruana, Christophe Cullin, Neville Vassallo, Ruben J Cauchi
A signature feature of age-related neurodegenerative proteinopathies is the misfolding and aggregation of proteins, typically amyloid-β (Aβ) in Alzheimer's disease (AD) and α-synuclein (α-syn) in Parkinson's disease (PD), into soluble oligomeric structures that are highly neurotoxic. Cellular and animal models that faithfully replicate the hallmark features of these disorders are being increasing exploited to identify disease-modifying compounds. Natural compounds have been identified as a useful source of bioactive molecules with promising neuroprotective capabilities...
December 2, 2016: Neuroscience Letters
https://www.readbyqxmd.com/read/27917040/two-new-species-and-a-remarkable-record-of-the-genus-dendronotus-from-the-north-pacific-and-arctic-oceans-nudibranchia
#5
Tatiana Korshunova, Nadezhda Sanamyan, Olga Zimina, Karin Fletcher, Alexander Martynov
Two new species of the nudibranch genus Dendronotus, Dendronotus arcticussp. n. and Dendronotus robilliardisp. n., are described from the Arctic and North Pacific oceans respectively, based on morphological and molecular data, and the North Pacific Dendronotus albus is revealed to be a species complex. The species Dendronotus robilliardisp. n. is described from the northwestern Pacific (Kamchatka) differing from the northeastern Pacific Dendronotus albus by molecular and morphological data. The synonymy of Dendronotus diversicolor with Dendronotus albus is confirmed by analysis of their original descriptions...
2016: ZooKeys
https://www.readbyqxmd.com/read/27913993/antifreeze-glycopeptides-from-structure-and-activity-studies-to-current-approaches-in-chemical-synthesis
#6
REVIEW
Małgorzata Urbańczyk, Jerzy Góra, Rafał Latajka, Norbert Sewald
Antifreeze glycopeptides (AFGPs) are a class of biological antifreeze agents found predominantly in Arctic and Antarctic species of fish. They possess the ability to regulate ice nucleation and ice crystal growth, thus creating viable life conditions at temperatures below the freezing point of body fluids. AFGPs usually consist of 4-55 repetitions of the tripeptide unit Ala-Ala-Thr that is O-glycosylated at the threonine side chains with β-D-galactosyl-(1 → 3)-α-N-acetyl-D-galactosamine. Due to their interesting properties and high antifreeze activity, they have many potential applications, e...
December 2, 2016: Amino Acids
https://www.readbyqxmd.com/read/27910905/magnitude-and-pattern-of-arctic-warming-governed-by-the-seasonality-of-radiative-forcing
#7
R Bintanja, F Krikken
Observed and projected climate warming is strongest in the Arctic regions, peaking in autumn/winter. Attempts to explain this feature have focused primarily on identifying the associated climate feedbacks, particularly the ice-albedo and lapse-rate feedbacks. Here we use a state-of-the-art global climate model in idealized seasonal forcing simulations to show that Arctic warming (especially in winter) and sea ice decline are particularly sensitive to radiative forcing in spring, during which the energy is effectively 'absorbed' by the ocean (through sea ice melt and ocean warming, amplified by the ice-albedo feedback) and consequently released to the lower atmosphere in autumn and winter, mainly along the sea ice periphery...
December 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27908741/resolving-interspecific-relationships-within-evolutionarily-young-lineages-using-rna-seq-data-an-example-from-pedicularis-section-cyathophora-orobanchaceae
#8
Hong-Juan Wang, Wei-Tao Li, Ya-Nan Liu, Fu-Sheng Yang, Xiao-Quan Wang
Phylogenomics has shown great potential in resolving evolutionary relationships at different taxonomical levels. However, it remains controversial whether all orthologous genes under different selective pressures can be concatenated for phylogenomic reconstruction. Here we used sect. Cyathophora of Pedicularis, one of the most species-rich genera of angiosperms in the alpine and arctic regions of the Northern Hemisphere, as a model to investigate the efficiency of RNA-seq in resolving relationships of closely related congeneric species...
November 28, 2016: Molecular Phylogenetics and Evolution
https://www.readbyqxmd.com/read/27906118/social-correlates-of-term-small-for-gestational-age-babies-in-a-russian-arctic-setting
#9
Anna A Usynina, Andrej M Grjibovski, Jon Øyvind Odland, Alexandra Krettek
BACKGROUND: Small for gestational age (SGA) births have been associated with both short- and long-term adverse health outcomes. Although social risk factors for SGA births have been studied earlier, such data are limited from Northern Russia. OBJECTIVE: We assessed maternal social risk factors for term SGA births based on data from the population-based Murmansk County Birth Registry (MCBR). DESIGN: Data on term live-born singleton infants born between 2006 and 2011 in Murmansk County were obtained from the MCBR...
2016: International Journal of Circumpolar Health
https://www.readbyqxmd.com/read/27904806/dominance-relationships-in-a-family-pack-of-captive-arctic-wolves-canis-lupus-arctos-the-influence-of-competition-for-food-age-and-sex
#10
Simona Cafazzo, Martina Lazzaroni, Sarah Marshall-Pescini
BACKGROUND: Dominance is one of the most pervasive concepts in the study of wolf social behaviour but recently its validity has been questioned. For some authors, the bonds between members of wolf families are better described as parent-offspring relationships and the concept of dominance should be used just to evaluate the social dynamics of non-familial captive pack members (e.g., Mech & Cluff, 2010). However, there is a dearth of studies investigating dominance relationships and its correlates in wolf family packs...
2016: PeerJ
https://www.readbyqxmd.com/read/27902346/hymenobacter-rutilus-sp-nov-isolated-from-marine-sediment-in-arctic
#11
Myong Chol Kim, Chol Myong Kim, Ok Chol Kang, Yumin Zhang, Zuobing Liu, Danzeng Wangmu, Ziyan Wei, Yao Huang, Fang Peng
Strain K2-33028T, appeared brick-red colony on R2A plate, was isolated from marine sediment sample in Kings Bay, Svalbard Archipelago, Norway. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain K2-33028T belonged to the genus Hymenobacter. Cells were Gram-reaction-negative, non-spore-forming, aerobic, rod-shaped bacterium without motility. Growth occurred at 4-37℃ (optimum 28℃) and at pH 6.0-8.0 (optimum pH 7.0). Cells contained menaquinone-7, as the main respiratory quinone, and iso-C15:0, summed feature 3 (comprising C16:1 ω7c and/or C16:1 ω6c), C16:1 ω5c, summed feature 4 (comprising anteiso-C17:1 B and/or iso-C17:1 I) and anteiso-C15:0 as the major cellular fatty acids...
November 21, 2016: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/27902292/terrimonas-crocea-sp-nov-isolated-from-the-till-of-high-arctic-glacier-midtre-lov%C3%A3-nbreen-in-the-west-svalbard-archipelago
#12
Myong Chol Kim, Ok Chol Kang, Chol Myong Kim, Yumin Zhang, Zuobing Liu, Ziyan Wei, Yao Huang, Wangmu Danzeng, Fang Peng
A yellow-pigmented bacteria strain, designated M1-33108T, was isolated from the till of high Arctic glacier Midtre Lovénbreen (MLB) near Ny-Ålesund, in the West Svalbard Archipelago, Norway. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain M1-33108T belonged to the genus Terrimonas and its closest neighbor was Terrimonas arctica R9-86T with 96.12% 16S rRNA gene sequence similarity. Strain M1-33108T was Gram-reaction-negative, aerobic, non-spore-forming, rod-shaped bacterium that lacked motility...
November 24, 2016: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/27902275/arcticibacterium-luteifluviistationis-gen-nov-sp-nov-isolated-from-arctic-seawater
#13
Dan-Dan Li, Ming Peng, Ning Wang, Xiu-Juan Wang, Xi-Ying Zhang, Xiu-Lan Chen, Hai-Nan Su, Yu-Zhong Zhang, Mei Shi
A Gram-staining-negative, aerobic, non-motile and yellow-pigmented bacterium, designated strain SM1504T, was isolated from Arctic seawater. It hydrolyzed aesculin and gelatin but did not reduce nitrate to nitrite. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain SM1504T constituted a distinct phylogenetic line within the family Cytophagaceae and was closely related to species of the genera Lacihabitans, Emticicia, Fluviimonas and Leadbetterella, with respect to which low sequence similarities between 88...
November 24, 2016: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/27901306/plants-microorganisms-and-soil-temperatures-contribute-to-a-decrease-in-methane-fluxes-on-a-drained-arctic-floodplain
#14
Min Jung Kwon, Felix Beulig, Iulia Ilie, Marcus Wildner, Kirsten Küsel, Lutz Merbold, Miguel D Mahecha, Nikita Zimov, Sergey A Zimov, Martin Heimann, Edward A G Schuur, Joel E Kostka, Olaf Kolle, Ines Hilke, Mathias Göckede
As surface temperatures are expected to rise in the future, ice-rich permafrost may thaw, altering soil topography and hydrology and creating a mosaic of wet and dry soil surfaces in the Arctic. Arctic wetlands are large sources of CH4 , and investigating effects of soil hydrology on CH4 fluxes is of great importance for predicting ecosystem feedback in response to climate change. In this study, we investigate how a decade-long drying manipulation on an Arctic floodplain influences CH4 -associated microorganisms, soil thermal regimes, and plant communities...
November 7, 2016: Global Change Biology
https://www.readbyqxmd.com/read/27898193/modeling-long-term-changes-in-tundra-carbon-balance-following-wildfire-climate-change-and-potential-nutrient-addition
#15
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/27897191/massive-remobilization-of-permafrost-carbon-during-post-glacial-warming
#16
T Tesi, F Muschitiello, R H Smittenberg, M Jakobsson, J E Vonk, P Hill, A Andersson, N Kirchner, R Noormets, O Dudarev, I Semiletov, Ö Gustafsson
Recent hypotheses, based on atmospheric records and models, suggest that permafrost carbon (PF-C) accumulated during the last glaciation may have been an important source for the atmospheric CO2 rise during post-glacial warming. However, direct physical indications for such PF-C release have so far been absent. Here we use the Laptev Sea (Arctic Ocean) as an archive to investigate PF-C destabilization during the last glacial-interglacial period. Our results show evidence for massive supply of PF-C from Siberian soils as a result of severe active layer deepening in response to the warming...
November 29, 2016: Nature Communications
https://www.readbyqxmd.com/read/27890103/the-genetic-structure-of-native-americans-in-north-america-based-on-the-globalfiler%C3%A2-strs
#17
Kelly L McCulloh, Jillian Ng, Robert F Oldt, Jessica A Weise, Joy Viray, Bruce Budowle, David Glenn Smith, Sreetharan Kanthaswamy
Current forensic STR databases, such as CODIS, lack population genetic data on Native American populations. Information from a geographically diverse array of tribes is necessary to provide improved statistical estimates of the strength of associations with DNA evidence. The Globalfiler® STR markers were used to characterize the genetic structure of ten tribal populations from seven geographic regions in North America, including those not presently represented in forensic databases. Samples from the Arctic region, Baja California, California/Great Basin, the Southeast, Mexico, the Midwest, and the Southwest were analyzed for allele frequencies, observed and expected heterozygosities, and F-statistics...
November 2016: Legal Medicine
https://www.readbyqxmd.com/read/27881974/the-microbiome-and-occurrence-of-methanotrophy-in-carnivorous-sponges
#18
Jon T Hestetun, Håkon Dahle, Steffen L Jørgensen, Bernt R Olsen, Hans T Rapp
As shown by recent studies, filter-feeding sponges are known to host a wide variety of microorganisms. However, the microbial community of the non-filtering carnivorous sponges (Porifera, Cladorhizidae) has been the subject of less scrutiny. Here, we present the results from a comparative study of the methanotrophic carnivorous sponge Cladorhiza methanophila from a mud volcano-rich area at the Barbados Accretionary Prism, and five carnivorous species from the Jan Mayen Vent Field (JMVF) at the Arctic Mid-Ocean Ridge...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27881760/changes-in-composition-and-abundance-of-functional-groups-of-arctic-fungi-in-response-to-long-term-summer-warming
#19
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/27881759/effects-of-sea-ice-cover-on-satellite-detected-primary-production-in-the-arctic-ocean
#20
Mati Kahru, Zhongping Lee, B Greg Mitchell, Cynthia D Nevison
The influence of decreasing Arctic sea ice on net primary production (NPP) in the Arctic Ocean has been considered in multiple publications but is not well constrained owing to the potentially large errors in satellite algorithms. In particular, the Arctic Ocean is rich in coloured dissolved organic matter (CDOM) that interferes in the detection of chlorophyll a concentration of the standard algorithm, which is the primary input to NPP models. We used the quasi-analytic algorithm (Lee et al 2002 Appl. Opti...
November 2016: Biology Letters
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