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Arctic Sun

Hui Peng, Chunli Chen, Jenna Cantin, David M V Saunders, Jianxian Sun, Song Tang, Garry Codling, Markus Hecker, Steve Wiseman, Paul D Jones, An Li, Karl J Rockne, Neil C Sturchio, Minghong Cai, John P Giesy
The majority of halogenated organic compounds present in the environment remain unidentified. To address this data gap, we recently developed an untargeted method (data-independent precursor isolation and characteristic fragment; DIPIC-Frag) for identification of unknown organo-bromine compounds. In this study, the method was adapted to enable untargeted screening of natural and synthetic organo-iodine compounds (NSOICs) in sediments. A total of 4,238 NSOIC peaks were detected in sediments from Lake Michigan...
September 20, 2016: Environmental Science & Technology
Damien Tran, Mohamedou Sow, Lionel Camus, Pierre Ciret, Jorgen Berge, Jean-Charles Massabuau
Although the prevailing paradigm has held that the polar night is a period of biological quiescence, recent studies have detected noticeable activity levels in marine organisms. In this study, we investigated the circadian rhythm of the scallop Chlamys islandica by continuously recording the animal's behaviour over 3 years in the Arctic (Svalbard). Our results showed that a circadian rhythm persists throughout the polar night and lasts for at least 4 months. Based on observations across three polar nights, we showed that the robustness and synchronicity of the rhythm depends on the angle of the sun below the horizon...
2016: Scientific Reports
Wenhan Cheng, Liguang Sun, Linda E Kimpe, Mark L Mallory, John P Smol, Lauren R Gallant, Jinping Li, Jules M Blais
Seabirds are major vertebrates in the coastal ecosystems of the Canadian High Arctic, where they transport substantial amounts of marine-derived nutrients and pollutants from oceans to land by depositing guano and stomach oils to their nesting area, which often includes nearby freshwater ponds. Here we present novel indicators for evaluating the impact of seabirds on freshwater ecosystems. The ratio of cholesterol/(cholesterol + sitosterol) in pond sediments showed significant enrichment near a nesting colony of northern fulmars (Fulmarus glacialis) and was significantly correlated with ornithogenic enrichment of sediment as determined by sedimentary δ(15)N...
September 6, 2016: Environmental Science & Technology
Natalie T Boelman, Troy S Magney, Barry A Logan, Kevin L Griffin, Jan U H Eitel, Heather Greaves, Case M Prager, Lee A Vierling
As the Arctic warms, tundra vegetation is becoming taller and more structurally complex, as tall deciduous shrubs become increasingly dominant. Emerging studies reveal that shrubs exhibit photosynthetic resource partitioning, akin to forests, that may need accounting for in the "big leaf" net ecosystem exchange models. We conducted a lab experiment on sun and shade leaves from S. pulchra shrubs to determine the influence of both constitutive (slowly changing bulk carotenoid and chlorophyll pools) and facultative (rapidly changing xanthophyll cycle) pigment pools on a suite of spectral vegetation indices, to devise a rapid means of estimating within canopy resource partitioning...
September 2016: Oecologia
Arnoldus Schytte Blix
This Review presents a broad overview of adaptations of truly Arctic and Antarctic mammals and birds to the challenges of polar life. The polar environment may be characterized by grisly cold, scarcity of food and darkness in winter, and lush conditions and continuous light in summer. Resident animals cope with these changes by behavioural, physical and physiological means. These include responses aimed at reducing exposure, such as 'balling up', huddling and shelter building; seasonal changes in insulation by fur, plumage and blubber; and circulatory adjustments aimed at preservation of core temperature, to which end the periphery and extremities are cooled to increase insulation...
April 15, 2016: Journal of Experimental Biology
Laura M Martinez-Levasseur, Chris M Furgal, Mike O Hammill, Gary Burness
Walruses, Odobenus rosmarus, play a key role in the Arctic ecosystem, including northern Indigenous communities, which are reliant upon walruses for aspects of their diet and culture. However, walruses face varied environmental threats including rising sea-water temperatures and decreasing ice cover. An underappreciated threat may be the large amount of solar ultraviolet radiation (UV) that continues to reach the Arctic as a result of ozone loss. UV has been shown to negatively affect whales. Like whales, walrus skin is unprotected by fur, but in contrast, walruses spend long periods of time hauled-out on land...
2016: PloS One
Sun-Yong Ha, Jun-Oh Min, Hyun Min Joo, Kyung Ho Chung, Kyung-Hoon Shin, EunJin Yang, Sung-Ho Kang
The net carbon uptake rate and net production rate of mycosporine-like amino acids (MAAs) were measured in phytoplankton from 2 different melt ponds (MPs; closed and open type pond) in the western Arctic Ocean using a (13) C stable isotope tracer technique. The Research Vessel Araon visited ice-covered western-central basins situated at 82°N and 173°E in the summer of 2012, when Arctic sea ice declined to a record minimum. The average net carbon uptake rate of the phytoplankton in polycarbonate (PC) bottles in the closed MP was 3...
October 2014: Journal of Phycology
Y M Li, Y Zhang, W J Zhu, S Q Yan, J H Sun
B chromosomes are dispensable and co-exist with autosomal and sex chromosomes. The karyotype of the Chinese raccoon dog (Nyctereutes procyonoides procyonoides) comprises 0-4 B chromosomes. The proto-oncogene KIT is found on all B chromosomes of the Chinese raccoon dog. In the present study, partial DNA and mRNA sequences of KIT were amplified and sequenced from four individuals containing B chromosomes. Sequence analyses revealed that polymorphisms including single nucleotide polymorphisms (SNPs) and inserts/deletions were rich in the KIT gene of Chinese raccoon dog at the genomic level...
2016: Genetics and Molecular Research: GMR
Ying Lei, Yu Liu, Bo Sun, Changfeng Sun
In this study, spruce tree rings from the southern slope of mid-Qinling Mountains were adopted to investigate the characteristics of average minimum temperatures during the past 138 years. Analysis showed that the interannual variability in radial growth of trees was positively correlated with the interannual variability of average minimum temperatures from previous December to current September (VTM DS) in the study area during 1955-2010 AD. Based on the correlation analysis, the VTM DS were reconstructed for 1876-2013 AD with an explained variance of 42...
February 21, 2016: International Journal of Biometeorology
Kushaharan Sathianathan, Ravindranath Tiruvoipati, Sanjiv Vij
AIM: To identify patient, cardiac arrest and management factors associated with hospital survival in comatose survivors of cardiac arrest. METHODS: A retrospective, single centre study of comatose patients admitted to our intensive care unit (ICU) following cardiac arrest during the twenty year period between 1993 and 2012. This study was deemed by the Human Research Ethics Committee (HREC) of Monash Health to be a quality assurance exercise, and thus did not require submission to the Monash Health HREC (Research Project Application, No...
February 4, 2016: World Journal of Critical Care Medicine
Mei-Ling Sun, Fang Zhao, Mei Shi, Xi-Ying Zhang, Bai-Cheng Zhou, Yu-Zhong Zhang, Xiu-Lan Chen
Although many kinds of exopolysaccharides (EPSs) from microorganisms have been used in industry, the exploration and utilization of EPSs from polar microorganisms is still rather rare. In this study, a flavobacterial strain, SM1127, from the Arctic brown alga Laminaria, was screened for its high EPS production (2.11 g/l) and was identified as belonging to the genus Polaribacter. The EPS secreted by strain SM1127 has a molecular mass of 220 kDa, and it mainly comprises N-acetyl glucosamine, mannose and glucuronic acid residues bound by heterogeneous linkages...
December 21, 2015: Scientific Reports
Zhi-Long Lou, Wei Cong, Qing-Feng Meng, Wu-Wen Sun, Si-Yuan Qin, Xiao-Xuan Zhang, Xing-Quan Zhu, Ai-Dong Qian
Until now, no information on Toxoplasma gondii seroprevalence in Arctic foxes (Vulpes lagopus) was available in China. A serological survey was undertaken to assess T. gondii seroprevalence in farmed Arctic foxes in eastern and northeastern China. Antibodies to T. gondii were examined in 1346 farmed Arctic foxes using the modified agglutination test (MAT). A total of 113 (8.39%, 95% confidence interval [CI] 6.91-9.87) serum samples were positive to T. gondii at a 1:25 cutoff. Seroprevalence of T. gondii infection in male Arctic foxes was 8...
December 2015: Vector Borne and Zoonotic Diseases
Chu Shen, Ning Xu, Yanyun Gao, Xiaoyue Sun, Ying Yin, Menghao Cai, Xiangshan Zhou, Yuanxing Zhang
Libertellenone H (1) was a promising antitumor diterpenoid isolated from Arctic fungus Eutypella sp. D-1, however, its production was very limited. In this study, we investigated the effects of ethanol on cell growth and libertellenone H production. The mycelium in ethanol-feeding cultures was fragmented and dispersed, and the titer of libertellenone H was remarkably increased to 4.88 mg l(-1) in an optimal feeding manner, which was 16.4-fold higher than the control group. To provide an insight into the cell response to ethanol, genes critical to the libertellenone H biosynthesis were successfully cloned and their transcription levels were determined...
February 2016: Bioprocess and Biosystems Engineering
Juan Yu, Zhouqing Xie, Liguang Sun, Hui Kang, Pengzhen He, Guangxi Xing
The biogeochemical cycles of CH4 over oceans are poorly understood, especially over the Arctic Ocean. Here we report atmospheric CH4 levels together with δ(13)C-CH4 from offshore China (31°N) to the central Arctic Ocean (up to 87°N) from July to September 2012. CH4 concentrations and δ(13)C-CH4 displayed temporal and spatial variation ranging from 1.65 to 2.63 ppm, and from -50.34% to -44.94% (mean value: -48.55 ± 0.84%), respectively. Changes in CH4 with latitude were linked to the decreasing input of enriched δ(13)C and chemical oxidation by both OH and Cl radicals as indicated by variation of δ(13)C...
2015: Scientific Reports
Jinyun Guo, Wang Li, Xin Liu, Qiaoli Kong, Chunmei Zhao, Bin Guo
To investigate the temporal-spatial distribution and evolutions of global Total Electron Content (TEC), we estimate the global TEC data from 1999 to 2013 by processing the GPS data collected by the International Global Navigation Satellite System (GNSS) Service (IGS) stations, and robustly constructed the TEC time series at each of the global 5°×2.5° grids. We found that the spatial distribution of the global TEC has a pattern where the number of TECs diminishes gradually from a low-latitude region to high-latitude region, and anomalies appear in the equatorial crest and Greenland...
2015: PloS One
Zhixin Hao, Di Sun, Jingyun Zheng
Based on observational data and Asian monsoon intensity datasets from China, the relationships between the East Asian winter monsoon index and winter temperature, the East Asian summer monsoon index and Meiyu precipitation over the middle and lower reaches of the Yangtze River, were analyzed. We found that the monsoon signals were reflected in the temperature and Meiyu precipitation variations. Thus, we used the reconstructed Meiyu precipitation and winter temperature series for the past 300 years and detected the summer/winter monsoon intensity signals using multi-taper spectral estimation method and wavelet analysis...
2015: PloS One
M Han, J-K Huang, H-Y Liu, W-A Wang, X-J Sun, F-D Huang
OBJECTIVE: We investigated the effects of genetic down- and up-regulation of sac1 expression on Aβ42 accumulation and the associated neural deficits in flies with direct expression of arctic mutant Aβ42 (Aβarc) in the neurons of GF pathway. MATERIALS AND METHODS: We genetically down-regulated and up-regulated the level of sac1, encoding a major phosphoinositide phosphatases in a disease model, in which arctic mutant Aβ42 is directly expressed in the neurons of a neural pathway of adult fruit flies...
2015: European Review for Medical and Pharmacological Sciences
Yanhui Sun, Qingzhu Zhang, Hui Wang, Wenxing Wang
The OH radical-initiated oxidation degradation of N-ethylperfluorobutyramide (EtFBA) in the presence of O2/NOx was investigated theoretically by using density functional theory (DFT). All possible pathways involved in the oxidation process were presented and discussed. The study shows that the H abstraction from the C(2)H(2) group in EtFBA is the most energetically favorable because of the lowest barrier and highest exothermicity. Canonical variational transition-state (CVT) theory with small curvature tunneling (SCT) contribution was used to predict the rate constants over the temperature range of 180-370 K...
September 2015: Chemosphere
Pingqing Fu, Kimitaka Kawamura, Jing Chen, Mingyue Qin, Lujie Ren, Yele Sun, Zifa Wang, Leonard A Barrie, Eri Tachibana, Aijun Ding, Youhei Yamashita
Organic aerosols are ubiquitous in the earth's atmosphere. They have been extensively studied in urban, rural and marine environments. However, little is known about the fluorescence properties of water-soluble organic carbon (WSOC) or their transport to and distribution in the polar regions. Here, we present evidence that fluorescent WSOC is a substantial component of High Arctic aerosols. The ratios of fluorescence intensity of protein-like peak to humic-like peak generally increased from dark winter to early summer, indicating an enhanced contribution of protein-like organics from the ocean to Arctic aerosols after the polar sunrise...
2015: Scientific Reports
Frida Lindwall, Patrick Faubert, Riikka Rinnan
Many hours of sunlight in the midnight sun period suggest that significant amounts of biogenic volatile organic compounds (BVOCs) may be released from arctic ecosystems during night-time. However, the emissions from these ecosystems are rarely studied and limited to point measurements during daytime. We measured BVOC emissions during 24-hour periods in the field using a push-pull chamber technique and collection of volatiles in adsorbent cartridges followed by analysis with gas chromatography-mass spectrometry...
2015: PloS One
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