研究者データベース

研究者情報

マスター

アカウント(マスター)

  • 氏名

    植竹 淳(ウエタケ ジユン), ウエタケ ジユン

所属(マスター)

  • 北方生物圏フィールド科学センター 森林圏ステーション 苫小牧研究林

所属(マスター)

  • 北方生物圏フィールド科学センター 森林圏ステーション 苫小牧研究林

独自項目

syllabus

  • 2021, 森林圏科学特論Ⅱ, Advanced Course in Forest Sphere Science II (Forest Dynamics), 修士課程, 環境科学院, 生物間相互作用、多種共存、攪乱,フェノロジー、授粉生態、生産性、植食 Biological interaction、species coexistence, disturbance, phenology, pollination ecology, productivity, herbivory
  • 2021, 一般教育演習(フレッシュマンセミナー), Freshman Seminar, 学士課程, 全学教育, フィールド、体験型、環境科学、自然、産業

researchmap

プロフィール情報

所属

  • 北海道大学, 北方生物圏フィールド科学センター, 准教授

学位

  • 博士(理学)(2007年03月 東京工業大学 生命理工学研究科)

プロフィール情報

  • 植竹, ウエタケ
  • 淳, ジユン
  • ID各種

    201201010170698354

対象リソース

所属

  • 北海道大学, 北方生物圏フィールド科学センター, 准教授

業績リスト

研究キーワード

  • 環境DNA   氷河生態系   バイオエアロゾル   好冷性微生物   

研究分野

  • 環境・農学 / 環境動態解析

経歴

  • 2021年02月 - 現在 北海道大学 北方生物圏フィールド科学センター 森林圏ステーション 准教授
  • 2017年04月 - 2020年12月 コロラド州立大学 大気科学部 研究員
  • 2016年04月 - 2017年03月 国立極地研究所 国際北極環境研究センター 特任研究員
  • 2007年04月 - 2016年03月 情報・システム研究機構 新領域融合研究センター 融合プロジェクト特任研究員

論文

  • Zichen He, Takeshi Naganuma, Ryosuke Nakai, Jun Uetake, Martin W. Hahn
    Current Microbiology 81 5 2024年03月14日 
    Abstract The diversity of bacteria associated with alpine lichens was profiled. Lichen samples belonging to the Umbilicariaceae family, commonly known as rock tripe lichens, were gathered from two distinct alpine fellfields: one situated on Mt. Brennkogel located in the Eastern European Alps (Austria), and the other on Mt. Stanley located in the Rwenzori mountains of equatorial Africa (Uganda). The primary aim of this research was to undertake a comparative investigation into the bacterial compositions, and diversities, identifying potential indicators and exploring their potential metabolisms, of these lichen samples. Bulk genomic DNA was extracted from the lichen samples, which was used to amplify the 18S rRNA gene by Sanger sequencing and the V3-V4 region of the 16S rRNA gene by Illumina Miseq sequencing. Examination of the fungal partner was carried out through the analysis of 18S rRNA gene sequences, belonging to the genus Umbilicaria (Ascomycota), and the algal partner affiliated with the lineage Trebouxia (Chlorophyta), constituted the symbiotic components. Analyzing the MiSeq datasets by using bioinformatics methods, operational taxonomic units (OTUs) were established based on a predetermined similarity threshold for the V3-V4 sequences, which were assigned to a total of 26 bacterial phyla that were found in both areas. Eight of the 26 phyla, i.e. Acidobacteriota, Actinomycota, Armatimonadota, Bacteroidota, Chloroflexota, Deinococcota, Planctomycetota, and Pseudomonadota, were consistently present in all samples, each accounting for more than 1% of the total read count. Distinct differences in bacterial composition emerged between lichen samples from Austria and Uganda, with the OTU frequency-based regional indicator phyla, Pseudomonadota and Armatimonadota, respectively. Despite the considerable geographic separation of approximately 5430 km between the two regions, the prediction of potential metabolic pathways based on OTU analysis revealed similar relative abundances. This similarity is possibly influenced by comparable alpine climatic conditions prevailing in both areas.
  • Jun Uetake, Masato Ono, Suzunosuke Usuba, Akane Tsushima, Nozomu Takeuchi
    2023年05月15日
  • Masato Ono, Nozomu Takeuchi, Akane Tsushima, Yukihiko Onuma, Kino Kobayashi, Daiki Seto, Suzunosuke Usuba, Fuki Konishi, Jun Uetake
    2023年05月15日
  • Onuma, Y, Takeuchi, N, Uetake, J, Niwano, M, Tanaka, S, Nagatsuka, N, Aoki, T
    Journal of Glaciology 2022年09月 [査読有り]
  • Jun Uetake, Denis Samyn, Simon Anguma, Nozomu Takeuchi
    Frontiers in Earth Science 10 2022年02月17日 [査読有り]
     
    Diverse microbes have been revealed to live in glaciers worldwide, but only a few biological studies were dedicated to glaciers in tropical Africa. These glaciers are shrinking rapidly and are expected to disappear shortly. In this study, we carried out biological and glaciological field observations on Stanley Glacier, the largest remaining glacier in the Rwenzori Mountains, Uganda, Africa. Microbial aggregates ranging from micrometer to centimeter in size were found on the glacier surface and contained moss and various types of Chlorophyta, among which a new endemic species of green alga. Concentrations of total impurities on the glacier surface, including microbial aggregates, varied spatially and decreased as altitude increased. The large microbial aggregates (larger than 4 cm in diameter) were found only at the glacier surface near the terminus and side margins, where the surface was less frequently covered with snow. It is also shown that the total organic matter on the glacier surface is determined by the timing of snow cover, which affects the quantity of solar radiation reaching the glacier ice surface. Furthermore, the total impurity content was negatively correlated with surface reflectivity, revealing their potential role in albedo reduction at the glacier surface through positive feedback between enhanced meltwater and increased biological growth.
  • Piotr Rozwalak, Paweł Podkowa, Jakub Buda, Przemysław Niedzielski, Szymon Kawecki, Roberto Ambrosini, Roberto S Azzoni, Giovanni Baccolo, Jorge L Ceballos, Joseph Cook, Biagio Di Mauro, Gentile Francesco Ficetola, Andrea Franzetti, Dariusz Ignatiuk, Piotr Klimaszyk, Edyta Łokas, Masato Ono, Ivan Parnikoza, Mirosława Pietryka, Francesca Pittino, Ewa Poniecka, Dorota L Porazinska, Dorota Richter, Steven K Schmidt, Pacifica Sommers, Juliana Souza-Kasprzyk, Marek Stibal, Witold Szczuciński, Jun Uetake, Łukasz Wejnerowski, Jacob Yde, Nozomu Takeuchi, Krzysztof Zawierucha
    The Science of the total environment 150874 - 150874 2021年10月07日 [査読有り]
     
    Cryoconite is a mixture of mineral and organic material covering glacial ice, playing important roles in biogeochemical cycles and lowering the albedo of a glacier's surface. Understanding the differences in structure of cryoconite across the globe can be important in recognizing past and future changes in supraglacial environments and ice-organisms-dust interactions. Despite the worldwide distribution and over a century of studies, the basic characteristics of cryoconite, including its forms and geochemistry, remain poorly studied. The major purpose of our study is the presentation and description of morphological diversity, chemical and photoautotrophs composition, and organic matter content of cryoconite sampled from 33 polar and mountain glaciers around the globe. Observations revealed that cryoconite included various morphologies including loose and granular forms. Granular cryoconite includes smooth, rounded, or irregularly shaped forms; with some having their surfaces covered by cyanobacteria filaments. The occurrence of granules increased with the organic matter content in cryoconite. Moreover, a major driver of cryoconite colouring was the concentration of organic matter and its interplay with minerals. The structure of cyanobacteria and algae communities in cryoconite differs between glaciers, but representatives of cyanobacteria families Pseudanabaenaceae and Phormidiaceae, and algae families Mesotaeniaceae and Ulotrichaceae were the most common. The most of detected cyanobacterial taxa are known to produce polymeric substances (EPS) that may cementing matter and form granules. Organic matter content in cryoconite varied between glaciers, ranging from 1% to >40%. The geochemistry of all the investigated samples reflected local sediment sources, except of highly concentrated Pb and Hg in cryoconite collected from European glaciers near industrialized regions, corroborating cryoconite as element-specific collectors and potential environmental indicator of anthropogenic activity. Our work supports a notion that cryoconite may be more than just simple sediment and instead exhibits complex structure with relevance for biodiversity and the functioning of glacial ecosystems.
  • Tomomi Nakashima, Jun Uetake, Takahiro Segawa, Lenka Procházková, Akane Tsushima, Nozomu Takeuchi
    Frontiers in Plant Science 12 2021年07月05日 [査読有り]
     
    Snow algae are photosynthetic microbes that inhabit the melting snow surface in alpine and polar regions. We analyzed the pigment and species composition of colored snow collected on Mt. Tateyama in Japan during the melting seasons of 2015 and 2016. High-performance liquid chromatographic analyses of the pigments extracted from the colored snow showed that their composition varied within the study area and were classified into four types: Type A (astaxanthin-monoester dominant), Type B (medium astaxanthin-monoester content), Type C (abundant primary carotenoids and free-astaxanthin), and Type D (abundant primary carotenoids and astaxanthin diesters). Types A and B were most commonly observed in the study area, whereas Types C and D appeared only at specific sites. Analysis of the 18S ribosomal RNA (18S rRNA) gene revealed six major amplicon sequence variants (ASVs) of snow algae, belonging to the Sanguina, Chloromonas, and Chlainomonas groups. The relative abundance of the algal ASVs showed that Sanguina was dominant (>48%) in both Types A and B, suggesting that the difference in astaxanthin abundance between the two types was caused by the production of pigments in the algal cells. The algal community structures of Types C and D differed from those of Types A and B, indicating that the primary carotenoids and astaxanthin diesters were derived from certain algal species in these types. Therefore, astaxanthin-rich Sanguina algae mostly induced the red snow that appeared widely in this alpine area; however, they were partially dominated by Chloromonas or Chlainomonas algae, causing different pigment compositions.
  • Jun Uetake, Yutaka Tobo, Satoshi Kobayashi, Keisuke Tanaka, Satoru Watanabe, Paul J. DeMott, Sonia M. Kreidenweis
    Science of The Total Environment 788 147623 - 147623 2021年05月 [査読有り]
  • K. Zawierucha, D. L. Porazinska, G. F. Ficetola, R. Ambrosini, G. Baccolo, J. Buda, J. L. Ceballos, M. Devetter, R. Dial, A. Franzetti, U. Fuglewicz, L. Gielly, E. Łokas, K. Janko, T. Novotna Jaromerska, A. Kościński, A. Kozłowska, M. Ono, I. Parnikoza, F. Pittino, E. Poniecka, P. Sommers, S. K. Schmidt, D. Shain, S. Sikorska, J. Uetake, N. Takeuchi
    Journal of Zoology 313 1 18 - 36 2021年01月 [査読有り]
     
    The worldwide distribution of microinvertebrates on glaciers, the coldest biome, is poorly known. Owing to their tolerance to hostile conditions, small size and dispersal abilities, nematodes, tardigrades and rotifers are considered cosmopolitan and together inhabit various ecosystems. In this study, we investigated their global distribution in cryoconite holes – a type of freshwater reservoir forming directly in the glacial ice that creates biodiversity hotspots on glaciers. We analysed cryoconite samples (using classical microscopic observations and environmental DNA metabarcoding) from 42 glaciers located around the world (the Arctic, Subarctic, Scandinavia, the Alps, the Caucasus, Siberia, Central Asia, Africa, South America and Antarctica), as well as using literature data. Samples from Antarctic, Karakoram and the Alps were analysed using next-generation sequencing (NGS) and classical observations under microscopes, while all other samples were analysed by microscope alone. Three general outcomes were found: (1) tardigrades and rotifers represented the most common invertebrates in cryoconite holes; (2) tardigrades and rotifers often coexisted together, with one or the other dominating, but the dominant taxon varied by region or by glacier; (3) nematodes – the most abundant, hyperdiverse and widespread metazoans on Earth, including in environments surrounding and seeding glacial surfaces – were consistently absent from cryoconite holes. Despite the general similarity of environmental conditions in cryoconite holes, the distribution of tardigrades and rotifers differed among glaciers, but not in any predictable way, suggesting that their distribution mostly depended on the random dispersal, extreme changes of supraglacial zone or competition. Although nematodes have been found in supraglacial habitats, cryoconite hole environments seem not to provide the necessary conditions for their growth and reproduction. Lack of physiological adaptations to permanently low temperatures (~0°C) and competition for different food resources in the cryoconite hole environment may explain the absence of nematodes in cryoconite holes.
  • Yutaka Tobo, Jun Uetake, Hitoshi Matsui, Nobuhiro Moteki, Yasushi Uji, Yoko Iwamoto, Kazuhiko Miura, Ryohei Misumi
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 125 23 2020年12月 [査読有り]
     
    Ice nucleating particles (INPs) originating from Asia are expected to have large impacts on aerosol-cloud-precipitation interactions on local, regional, and global scales. However, their seasonal variability is poorly understood. Here, we present a year-round record of atmospheric INPs measured on Tokyo Skytree, which is the world's tallest broadcasting tower located in the Tokyo Metropolitan area. The INP number concentrations showed relatively small variations in the temperature regime below -20 degrees C, whereas the values were episodically enhanced by long-range transported Asian dusts. On the other hand, the INP spectra in the temperature regime warmer than -20 degrees C exhibited measurable seasonal variations. Notably, the INP number concentrations in the temperature regime between -15 degrees C and -10 degrees C tended to indicate higher values in warm/wet seasons and lower values in cold/dry seasons. Our results suggest that Asian dust events and seasonal variations in certain particles of biological origin linked to local/regional meteorology might influence the seasonal trends of the INP spectra over the Tokyo Metropolitan area.
  • Jessie M Creamean, Thomas C J Hill, Paul J DeMott, Jun Uetake, Sonia Kreidenweis, Thomas A Douglas
    Environmental Research Letters 15 8 084022 - 084022 2020年08月05日 [査読有り]
  • Jun Uetake, Thomas C. J. Hill, Kathryn A. Moore, Paul J. DeMott, Alain Protat, Sonia M. Kreidenweis
    Proceedings of the National Academy of Sciences 117 24 13275 - 13282 2020年06月16日 [査読有り]
     
    Microorganisms are ubiquitous and highly diverse in the atmosphere. Despite the potential impacts of airborne bacteria found in the lower atmosphere over the Southern Ocean (SO) on the ecology of Antarctica and on marine cloud phase, no previous region-wide assessment of bioaerosols over the SO has been reported. We conducted bacterial profiling of boundary layer shipboard aerosol samples obtained during an Austral summer research voyage, spanning 42.8 to 66.5°S. Contrary to findings over global subtropical regions and the Northern Hemisphere, where transport of microorganisms from continents often controls airborne communities, the great majority of the bacteria detected in our samples were marine, based on taxonomy, back trajectories, and source tracking analysis. Further, the beta diversity of airborne bacterial communities varied with latitude and temperature, but not with other meteorological variables. Limited meridional airborne transport restricts southward community dispersal, isolating Antarctica and inhibiting microorganism and nutrient deposition from lower latitudes to these same regions. A consequence and implication for this region’s marine boundary layer and the clouds that overtop it is that it is truly pristine, free from continental and anthropogenic influences, with the ocean as the dominant source controlling low-level concentrations of cloud condensation nuclei and ice nucleating particles.
  • Yutaka Tobo, Kouji Adachi, Paul J. DeMott, Thomas C. J. Hill, Douglas S. Hamilton, Natalie M. Mahowald, Naoko Nagatsuka, Sho Ohata, Jun Uetake, Yutaka Kondo, Makoto Koike
    Nature Geoscience 12 4 253 - 258 2019年04月 [査読有り]
  • Jun Uetake, Naoko Nagatsuka, Yukihiko Onuma, Nozomu Takeuchi, Hideaki Motoyama, Teruo Aoki
    2019年01月08日 [査読無し]
     
    Cryoconite granules, which are dark-colored biological aggregates on glaciers, effectively accelerate the melting of glacier ice. Bacterial community varies with granule size, however, community change in space and their susceptibility to environmental factors has not been described yet. Therefore, we focused on bacterial community from 4 different granule sizes (30-249 μm, 250-750 μm, 750-1599 μm, more than 1600 μm diameter) in 10 glaciers in northwestern Greenland and their susceptibility for exogenous nutrients in cryoconite hole. A filamentous cyanobacterium Phormidesmis priestleyi, which has been frequently reported from glaciers in Arctic was abundant (10-26%) across any size of granules on most of glaciers. Bacterial community across glaciers became similar with size increase, and whence smallest size fractions contain more unique genera in each glacier. Multivariate analysis suggests that phosphate, which is significantly higher in one glacier (Scarlet Heart Glacier), is primary associated with bacterial beta diversity. Correlation coefficients between abundance of major genera and nutrients largely changed with granule size, suggesting that nutrients susceptibility to genera changes with growth process of granule (e.g. P. priestleyi was affected by nitrate in early growth stage).
  • Jun Uetake, Yutaka Tobo, Yasushi Uji, Thomas C J Hill, Paul J DeMott, Sonia M Kreidenweis, Ryohei Misumi
    Frontiers in microbiology 10 1572 - 1572 2019年 [査読有り]
     
    In order to study airborne bacterial community dynamics over Tokyo, including fine-scale correlations between airborne microorganisms and meteorological conditions, and the influence of local versus long-range transport of microbes, air samples were collected on filters for periods ranging from 48 to 72 h. The diversity of the microbial community was assessed by next generation sequencing. Predicted source regions of airborne particles, from back trajectory analyses, changed abruptly from the Pacific Ocean to the Eurasian Continent in the beginning of October. However, the microbial community composition and the alpha and beta diversities were not affected by this shift in meteorological regime, suggesting that long-range transport from oceanic or continental sources was not the principal determinant controlling the local airborne microbiome. By contrast, we found a significant correlation between the local meteorology, especially relative humidity and wind speed, and both alpha diversity and beta diversity. Among four potential local source categories (soil, bay seawater, river, and pond), bay seawater and soil were identified as constant and predominant sources. Statistical analyses point toward humidity as the most influential meteorological factor, most likely because it is correlated with soil moisture and hence negatively correlated with the dispersal of particles from the land surface. In this study, we have demonstrated the benefits of fine-scale temporal analyses for understanding the sources and relationships with the meteorology of Tokyo's "aerobiome."
  • Uetake, J., Nagatsuka, N., Onuma, Y., Takeuchi, N., Motoyama, H., Aoki, T.
    FEMS microbiology ecology 95 7 fiz075  2019年 [査読有り][通常論文]
  • Nozomu Takeuchi, Ryutaro Sakaki, Jun Uetake, Naoko Nagatsuka, Rigen Shimada, Masashi Niwano, Teruo Aoki
    Annals of Glaciology 59 77 21 - 30 2018年12月 [査読有り]
     
    AbstractCryoconite holes are water-filled cylindrical holes formed on ablation ice surfaces and commonly observed on glaciers worldwide. Temporal changes of cryoconite holes characteristically <5 cm in diameter were monitored with a time-lapse interval camera over 15 d during the melting season on Qaanaaq Glacier in northwest Greenland. The holes drastically changed their dimensions and synchronously collapsed twice during the study period. When the holes collapsed, the coverage of cryoconite on the ice surface increased from 1.0 to 3.5% in the field of view of the camera, and then decreased again to 0.4% after the holes reformed. Comparison with meteorological data showed that the collapses occurred in cloudy and rainy or windy weather conditions, corresponding to low shortwave solar radiation (68–126 W m−2, 40–55% of the incoming flux). In contrast, holes developed in sunny conditions correspond to high solar radiation (186–278 W m−2, 63–88%). Results suggest that the dimensions of holes drastically changed depending on the weather conditions and that frequent cloudy, warm and windy conditions would cause a decay of holes and weathering crust, inducing an increase in the cryoconite coverage on the ice, consequently darkening the glacier surface.
  • Takeuchi, N, R. Sakaki, J. Uetake, N. Nagatsuka, R. Shimada, M. Niwano, T. Aoki
    Ann. Glaciol. 59 1 - 10 2018年 [査読有り][通常論文]
  • Takahiro Segawa, Takahiro Yonezawa, Arwyn Edwards, Ayumi Akiyoshi, Sota Tanaka, Jun Uetake, Tristram Irvine-Fynn, Kotaro Fukui, Zhongqin Li, Nozomu Takeuchi
    JOURNAL OF BIOGEOGRAPHY 44 12 2849 - 2861 2017年12月 [査読有り][通常論文]
     
    AimCryoconite, a microbe-mineral aggregate found on glaciers worldwide, is formed by microbial phototrophs, principally cyanobacteria. Despite their ecological importance in supraglacial environments, the phylogeographical distributions of supraglacial cyanobacteria are poorly understood. Here, we investigate the biogeographical distribution of cyanobacteria on glaciers in the Antarctic, Arctic and Asia. LocationGlaciers in the Antarctic, Arctic and Asia. MethodsWe analysed contiguous sequences of 16S rRNA genes and 16S-23S internal transcribed spacer (ITS) regions, determined by a long read strategy and single-filament PCR analysis in 38 glacial samples. We analysed cyanobacterial distribution patterns and genetic differentiation. ResultsThe cyanobacterial 16S rRNA gene sequences were grouped into 20 operational taxonomic units (OTUs), and the six major OTUs that accounted for 88% of sequences were distributed broadly from polar to Asian glaciers, suggesting that they are cosmopolitan at the species level. However, analysis of the more variable ITS region revealed geographical differentiation at the strain level. Nineteen OTUs, including the six major OTUs, showed considerable genetic differentiation among geographical regions; at the population level, they are, thus, geographically restricted. Only one of the phylotype exhibits a population structure which does not show a relationship with geographical distribution, suggesting that is cosmopolitan, even at the strain level. Main conclusionsOur 16S rRNA gene analyses suggest a global distribution of species of cyanobacteria colonizing glacier surfaces; however, the 16S-23S ITS regions revealed that most of the phylotypes are fundamentally endemic to particular areas at the population level and indicate limited migration among regions. Our result suggests that selection pressures among geographical regions are strong driving forces shaping genetic structure in cyanobacteria.
  • Tsuji M, Uetake J, Tanabe Y
    Mycoscience 57 6 448 - 451 2016年11月 [査読有り][通常論文]
     
    Austre Broggerbreen is located in Ny-Alesund in the Svalbard archipelago, Norway, and is known as one of the most retreating glaciers in the world. We selected five sites in the retreating area and investigated the mycoflora in each of them. A total of 58 fungal strains were isolated and classified into 14 species (Cryptococcus gilvescens, Cryptococcus victoriae, Mrakia gelida, Mrakia robertii, Mrakia psychrophila, Rhodotorula glacialis, Rhodotorula psychrophenolica, Cladosporium cladosporioides, Thelebolus microsporus, Mortierella alpina, Mortierella polygonia, Mortierella elongata, Mortierella horticola, and Mucor hiemalis). We showed that the mycoflora clearly changes with distance from the glacier terminus in Austre Broggerbreen deglaciation area. (C) 2016 The Mycological Society of Japan. Published by Elsevier B.V. All rights reserved.
  • Uetake, J, S. Tanaka, T. Segawa, N. Takeuchi, N. Nagatsuka, H. Motoyama, T. Aoki
    FEMS Microbiology Ecology 92 9 2016年06月 [査読有り][通常論文]
     
    Cryoconite granules are aggregations of microorganisms with mineral particles that form on glacier surfaces. To understand the processes by which the granules develop, this study focused on the altitudinal distribution of the granules and photosynthetic microorganisms on the glacier, bacterial community variation with granules size and environmental factors affecting the growth of the granules. Size-sorted cryoconite granules collected from five different sites on Qaanaaq Glacier were analyzed. C and N contents were significantly higher in large (diameter greater than 250 μm) granules than in smaller (diameter 30-249 μm) granules. Bacterial community structures, based on 16S rRNA gene amplicon sequencing, were different between the smaller and larger granules. The filamentous cyanobacterium Phormidesmis priestleyi was the dominant bacterial species in larger granules. Multivariate analysis suggests that the abundance of mineral particles on the glacier surface is the main factor controlling growth of these cyanobacteria. These results show that the supply of mineral particles on the glacier enhances granule development, that P. priestleyi is likely the key species for primary production and the formation of the granules and that the bacterial community in the granules changes over the course of the granule development.
  • Naoko Nagatsuka, Nozomu Takeuchi, Jun Uetake, Rigen Shimada, Yukihiko Onuma, Sota Tanaka, Takanori Nakano
    Frontiers in Earth Science 4 93 2016年 [査読有り][通常論文]
     
    © 2016 Nagatsuka, Takeuchi, Uetake, Shimada, Onuma, Tanaka and Nakano. In order to better understand the source of minerals on the dark-colored ice, located in the Greenland ice sheet ablation zone, we analyzed the Sr and Nd isotopic ratios of minerals in cryoconite, which were collected from glaciers in northwest and southwest Greenland. We focused on the following: (i) comparison of the isotopes of minerals in cyroconite with those in sediments from local and distant areas, (ii) regional variations in western Greenland, and (iii) spatial variations across an individual a glacier. The mineral components of the cryoconite showed variable Sr and Nd isotopic ratios (87Sr/86 Sr: 0.711335 to 0.742406, εNd (0): −33.1 to −22.9), which corresponded to those of the englacial dust and moraine on and around the glaciers but were significantly different from those of the distant deserts that have been considered to be primary sources of mineral dust on the Greenland Ice Sheet. This suggests that the minerals within the cryoconites were mainly derived from local sediments, rather than from distant areas. The Sr ratios in the northwestern region were significantly higher than those in the southwestern region. This is probably due to geological differences in the source areas, such as the surrounding glaciers in each region. The isotopic ratios further varied spatially within a glacier (Qaanaaq and Kangerlussuaq areas), indicating that the silicate minerals on the glaciers were derived not from a single source but from multiple sources, such as englacial dust and wind-blown minerals from the moraine surrounding the glaciers.
  • 竹内 望, 永塚 尚子, 植竹 淳, 田中 聡太, 大沼 友貴彦, 島田 利元
    雪氷研究大会講演要旨集 2015 71 - 71 公益社団法人 日本雪氷学会/日本雪工学会 2015年
  • 中島 智美, 竹内 望, 植竹 淳, 瀬川 高弘, 田邊 優貴子, 渡辺 憲一, 辻 雅晴, 宮内 謙史郎, 岡本 智夏, 堀 燿一朗
    雪氷研究大会講演要旨集 2015 181 - 181 公益社団法人 日本雪氷学会/日本雪工学会 2015年
  • 田中 聡太, 竹内 望, 朝岡 良浩, 植竹 淳
    雪氷研究大会講演要旨集 2015 2 - 2 公益社団法人 日本雪氷学会/日本雪工学会 2015年
  • 近野 雄大, 竹内 望, 植竹 淳, 原 宏輔
    雪氷研究大会講演要旨集 2015 1 - 1 公益社団法人 日本雪氷学会/日本雪工学会 2015年
  • Jun Uetake, Sota Tanaka, Kosuke Hara, Yukiko Tanabe, Denis Samyn, Hideaki Motoyama, Satoshi Imura, Shiro Kohshima
    PLOS ONE 9 11 2014年11月 [査読有り][通常論文]
     
    Tropical regions are not well represented in glacier biology, yet many tropical glaciers are under threat of disappearance due to climate change. Here we report a novel biogenic aggregation at the terminus of a glacier in the Rwenzori Mountains, Uganda. The material was formed by uniseriate protonemal moss gemmae and protonema. Molecular analysis of five genetic markers determined the taxon as Ceratodon purpureus, a cosmopolitan species that is widespread in tropical to polar region. Given optimal growing temperatures of isolate is 20-30 degrees C, the cold glacier surface might seem unsuitable for this species. However, the cluster of protonema growth reached approximately 10 degrees C in daytime, suggesting that diurnal increase in temperature may contribute to the moss's ability to inhabit the glacier surface. The aggregation is also a habitat for microorganisms, and the disappearance of this glacier will lead to the loss of this unique ecosystem.
  • Aoki, T, S. Matoba, S. Yamaguchi, T. Tanikawa, M. Niwano, K. Kuchiki, K. Adachi, J. Uetake, H. Motoyama, M. Hori
    Bulletin of Glaciological Research 32 0 21 - 31 2014年03月 [査読有り][通常論文]
  • Nozomu Takeuchi, Naoko Nagatsuka, Jun Uetake, Rigen Shimada
    Bulletin of Glaciological Research 32 1 85 - 94 2014年 [査読有り][通常論文]
     
    Spatial variations in impurities (cryoconite) on the glacier surface were investigated on Qaanaaq Ice Cap and Tugto Glacier in the northwest Greenland in the melting season of 2012. Abundance of impurities ranged from 0.36 to 119 gm-2 (dry weight, mean: 18.8 gm-2) on bare ice and from 0.01 to 8.7 gm-2 (mean: 3.6 gm-2) on snow surface at the study sites. On Qaanaaq Glacier (an outlet glacier of Qaanaaq Ice Cap) impurity abundance was greatest at mid-elevations, with fewer impurities at upper and lower sites. Surface reflectivity was lowest in the mid-elevation area, suggesting that impurities substantially reduce ice surface albedo at mid-elevations on glacier surfaces. Organic matter content in the impurities ranged from 1.4 to 12.0% (mean: 5.4%) on the ice and from 3.2 to 10.6% (mean: 6.7%) on the snow surface. Microscopy revealed that impurities in the ice areas mainly consisted of cryoconite granules, which are aggregations of mineral particles, filamentous cyanobacteria and other microbes and organic matter, while those in snow areas consisted of mineral particles and snow algae. Results suggest that the spatial variation in the abundance of impurities is caused by supply of mineral particles both from air and ice, and microbial production of organic matter on the glacier surface.© Japanese Society of Snow and Ice.
  • Naoko NAGATSUKA, Nozomu TAKEUCHI, Jun UETAKE, Rigen SHIMADA
    Bulletin of Glaciological Research 32 107 - 114 2014年
  • Aoki, T, S. Matoba, J. Uetake, N. Takeuchi, H. Motoyama
    Bulletin of Glaciological Research 32 3 - 20 The Japanese Society of Snow and Ice = 日本雪氷学会 2014年 [査読有り][通常論文]
     
    Field activities of the "Snow Impurity and Glacial Microbe effects on abrupt warming in the Arctic" (SIGMA) Project in Greenland in the summer season of 2011-2013 are reported; this consists of (1) glaciological and meteorological observations and (2) biological observations. In 2011, we conducted a field reconnaissance in the Qaanaaq, Ilulissat and Kangerlussuaq areas to enable continuous meteorological observations with automatic weather stations (AWS), campaign observations for glaciology, meteorology and Biology and shallow ice core drilling, which were planned for 2012-2014. Based on the results, we chose the Qaanaaq area in northwest Greenland as our main activity area and the Kangerlussuaq area in mid-west Greenland partly for biological observations. In 2012, we conducted field observations for (1) and (2) mentioned above together with installations of two AWSs at site SIGMA-A on The Greenland ice sheet (GrIS) and at site SIGMA-B on the Qaanaaq ice cap (QIC) from June to August. Surface snow and ice over all of the QIC melted in July and August 2012, and most of the Glacier surface appeared to be dark-colored, probably due to mineral dust and glacial microbial products. In 2013, we carried out similar observations in the Qaanaaq area. However, the weather and Glacier surface conditions were considerably different from those in 2012. Snow cover over the summer of 2013 remained over large areas with elevations higher than about 700 m on QIC. Biological activity on the Glacier surface appears to be substantially lower as compared to that in 2012. ? Japanese Society of Snow and Ice.
  • Teruo Aoki, Katsuyuki Kuchiki, Masashi Niwano, Sumito Matoba, Jun Uetake, Kazuhiko Masuda, Hiroshi Ishimoto
    2013年
  • Fumio Nakazawa, Jun Uetake, Yoshihisa Suyama, Ryo Kaneko, Nozomu Takeuchi, Koji Fujita, Hideki Motoyama, Satoshi Imura, Hiroshi Kanda
    Environmental Research Letters 8 1 014032  2013年01月 [査読有り][通常論文]
  • Jun Uetake, Yoshitaka Yoshimura, Naoko Nagatsuka, Hiroshi Kanda
    FEMS MICROBIOLOGY ECOLOGY 82 2 279 - 286 2012年11月 [査読有り][通常論文]
     
    Psychrophilic yeasts have been isolated from supra- and subglacial ice at many sites worldwide. To understand the ecology of psychrophilic yeasts on glaciers, we focused on their adaptation to wide range of nutrient concentrations and their distribution with altitude on the Gulkana Glacier in Alaska. We found various culturable psychrophilic yeasts on the ice surfaces of the glacier, and 11 species were isolated with incubation at 4 degrees C in four different dilutions of agar medium. Some of our isolated species (Rhodotorula psychrophenolica, Rhodotorula aff. psychrophenolica, Rhodotorula glacialis, and Basidiomycota sp. 1) can grow on the low dissolved organic matter (DOC) concentrations medium (7.6mgL-1) which is close to the typical level of supraglacial melt water, suggesting that these species can inhabit in any supraglacial meltwater. Otherwise, most of other species were isolated only from higher DOC concentration medium (183mgL-118.3gL-1), suggesting that these are inhabitant around the cryoconite, because DOC concentrations in melted surface-ice contained cryoconite is much higher than in melted water. Similarity of altitudinal distribution between culturable yeast and algal biomass suggests that the ecological role played by the cold-adapted yeasts is as organic matter decomposers and nutrient cyclers in glacier ecosystem.
  • 的場 澄人, 植竹 淳, 青木 輝夫
    雪氷研究大会講演要旨集 2012 151 - 151 公益社団法人 日本雪氷学会/日本雪工学会 2012年
  • 原 宏輔, 田中 聡太, 植竹 淳, 幸島 司郎
    雪氷研究大会講演要旨集 2012 216 - 216 公益社団法人 日本雪氷学会/日本雪工学会 2012年
  • 植竹 淳, 本山 秀明, 青木 輝夫
    雪氷研究大会講演要旨集 2012 155 - 155 公益社団法人 日本雪氷学会/日本雪工学会 2012年
  • 植竹 淳, 東 久美子, 倉元 隆之, 平林 幹啓, 三宅 隆之, 本山 秀明
    雪氷研究大会講演要旨集 2012 219 - 219 公益社団法人 日本雪氷学会/日本雪工学会 2012年
  • 植竹 淳, 田邊 優貴子, 原 宏輔, 田中 聡太, 本山 秀明, 幸島 司郎
    雪氷研究大会講演要旨集 2012 54 - 54 公益社団法人 日本雪氷学会/日本雪工学会 2012年
  • 田中 モナミ, 竹内 望, 大沼 友貴彦, 植竹 淳
    雪氷研究大会講演要旨集 2012 201 - 201 公益社団法人 日本雪氷学会/日本雪工学会 2012年
  • Fumio Nakazawa, Takayuki Miyake, Koji Fujita, Nozomu Takeuchi, Jun Uetake, Toshiyuki Fujiki, Vladimir Aizen, Masayoshi Nakawo
    ARCTIC ANTARCTIC AND ALPINE RESEARCH 43 1 66 - 72 2011年02月 [査読有り][通常論文]
     
    In this study, we used a 4.00-m pit on Belukha glacier in Russia's Altai region and attempted to establish the timing of chemical deposition events by analyzing pollen profiles. As the pollen deposition of each examined taxon on the glacier surfaces followed a distinct seasonal phenology, seasonal layers could be identified over a two-year period. The seasonal layer boundaries reconstructed from the pollen analyses were in close agreement with the in situ observations and indicated that the snow deposition on the glacier originates mainly from summer precipitation. The record of oxygen isotope ratios showed a relatively high mean value of 13.3 parts per thousand, which was attributed to the absence of winter depositions. The formate (HCOO-) concentration records displayed seasonal variation with the highest emissions occurring in the spring, and a dust event in the spring of 2003 was detected from the Mg2+, Ca2+, and dust concentration profiles. Taken together, these results suggest the analysis of pollen profiles in combination with chemical data in snow pits and ice cores may lead to better reconstruction of seasonal variation.
  • Jun Uetake, Shiro Kohshima, Fumio Nakazawa, Nozomu Takeuchi, Koji Fujita, Takayuki Miyake, Hideki Narita, Vladimir Aizen, Masayoshi Nakawo
    JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES 116 1 2011年02月 [査読有り][通常論文]
     
    Cold environments, including glacier ice and snow, are known habitats for cold-adapted microorganisms. We investigated the potential for cold-adapted yeast to have propagated in the snow of the high-altitude Belukha glacier. We detected the presence of highly concentrated yeast (over 10(4) cells mL(-1)) in samples of both an ice core and firn snow. Increasing yeast cell concentrations in the same snow layer from July 2002 to July 2003 suggests that the yeast cells propagated in the glacier snow. A cold-adapted Rhodotorula sp. was isolated from the snow layer and found to be related to psychrophilic yeast previously found in other glacial environments (based on the D1/D2 26S rRNA domains). 26S rRNA clonal analysis directly amplified from meltwater within the ice core also revealed the presence of genus Rhodotorula. Analyses of the ice core showed that all peaks in yeast concentration corresponded to the peaks in indices of surface melting. These results support the hypothesis that occasional surface melting in an accumulation area is one of the major factors influencing cold-adapted yeast propagation.
  • Sachiko Okamoto, Koji Fujita, Hideki Narita, Jun Uetake, Nozomu Takeuchi, Takayuki Miyake, Fumio Nakazawa, Vladimir B. Aizen, Stanislav A. Nikitin, Masayoshi Nakawo
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 116 2 D02110  2011年01月 [査読有り][通常論文]
     
    In a previous study, past summer temperatures were reconstructed from melt features in the Belukha ice core, Siberian Altai. We evaluated the climatic representativeness of net accumulation and melt features by comparing two Belukha ice cores retrieved at neighboring sites by different institutions and dated by different methods. Melt features in both cores showed a significant correlation, but the trends of net accumulation were different between the cores. Melt features corresponded to the retreat rate of a glacier terminus in a neighboring mountain range. These findings demonstrate the spatial representativeness of melt features in the ice cores. We reevaluated an equation formulated for reconstructions of summer temperature, as used in a previous study, and found that it underestimates temperature. We propose an alternative equation to obtain more reliable summer temperatures from melt features and net accumulation records for the period from 1914 to 2003.
  • Jun Uetake, Hideaki Motoyama, Takayuki Miyake, Teruya Maki, Atsushi Matsuki, Tomoya Baba
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research 2011 104  2011年 [査読有り][通常論文]
  • Takayuki Kuramoto, Kumiko Goto-Azuma, Motohiro Hirabayashi, Takayuki Miyake, Hideaki Motoyama, Jun Uetake
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research 2010 86  2010年 [査読有り][通常論文]
  • Jun Uetake, Jun Uetake, Kumiko Azuma, Takayuki Kuramoto, Hideaki Motoyama, Hiroshi Kanda
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research 2010 148  2010年 [査読有り][通常論文]
  • 植竹 淳, 永塚 尚子, 吉村 義隆
    雪氷研究大会講演要旨集 2009 136 - 136 公益社団法人 日本雪氷学会/日本雪工学会 2009年
  • 岡本 祥子, 藤田 耕史, 成田 英器, 植竹 淳, 竹内 望, 三宅 隆之, 中澤 文男, Aizen Vladimir, Nikitin Stanislav, 中尾 正義
    雪氷研究大会講演要旨集 2009 134 - 134 公益社団法人 日本雪氷学会/日本雪工学会 2009年
  • 伊藤 弘樹, 竹内 望, 幸島 司郎, 植竹 淳
    雪氷研究大会講演要旨集 2009 25 - 25 公益社団法人 日本雪氷学会/日本雪工学会 2009年
  • Fumio Nakazawa, Jun Uetake, Hiroshi Kanda, Yoshihisa Suyama, Nozomu Takeuchi, Koji Fujita
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research 2009 127  2009年 [査読有り][通常論文]
  • Fumio Nakazawa, Jun Uetake, Hiroshi Kanda
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research 2008 78  2008年 [査読有り][通常論文]
  • Jun Uetake, Hideaki Motoyama, Hiroshi Kanda
    Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research 2008 146  2008年 [査読有り][通常論文]
  • Shiro Kohshima, Nozomu Takeuchi, Jun Uetake, Takayuki Shiraiwa, Ryu Uemura, Naohiro Yoshida, Sumito Matoba, Maria Angelica Godoi
    Global and Planetary Change 59 1-4 236 - 244 2007年10月 [査読有り][通常論文]
     
    Snow algae in a 45.97-m-long ice core from the Tyndall Glacier (50°59′05″S, 73°31′12″W, 1756 m a.s.l.) in the Southern Patagonian Icefield were examined for potential use in ice core dating and estimation of the net accumulation rate. The core was subjected to visual stratigraphic observation and bulk density measurements in the field, and later to analyses of snow algal biomass, water isotopes (18O, D), and major dissolved ions. The ice core contained many algal cells that belonged to two species of snow algae growing in the snow near the surface: Chloromonas sp. and an unknown green algal species. Algal biomass and major dissolved ions (Na+, K+, Mg2+, Ca2+, Cl-, SO42-) exhibited rapid decreases in the upper 3 m, probably owing to melt water elution and/or decomposition of algal cells. However, seasonal cycles were still found for the snow algal biomass, 18O, D-excess, and major ions, although the amplitudes of the cycles decreased with depth. Supposing that the layers with almost no snow algae were the winter layers without the melt water essential to algal growth, we estimated that the net accumulation rate at this location was 12.9 m a- 1 from winter 1998 to winter 1999, and 5.1 m from the beginning of winter to December 1999. These estimates are similar to the values estimated from the peaks of 18O (17.8 m a- 1 from summer 1998 to summer 1999 and 11.0 m from summer to December 1999) and those of D-excess (14.7 m a- 1 from fall 1998 to fall 1999 and 8.6 m a- 1 from fall to December 1999). These values are much higher than those obtained by past ice core studies in Patagonia, but are of the same order of magnitude as those predicted from various observations at ablation areas of Patagonian glaciers. © 2006 Elsevier B.V. All rights reserved.
  • 岡本 祥子, 藤田 耕史, 成田 英器, 植竹 淳, 竹内 望, 三宅 隆之, 中澤 文男
    日本雪氷学会全国大会講演予稿集 2007 7 - 7 公益社団法人 日本雪氷学会 2007年
  • Nozomu Takeuchi, Roman Dial, Shiro Kohshima, Takahiro Segawa, Jun Uetake
    GEOPHYSICAL RESEARCH LETTERS 33 21 2006年11月 [査読有り][通常論文]
     
    Red snow caused by algal bloom is common on glaciers and snowfields worldwide. Description of spatial distributions of snow algal blooms is important for understanding snow algae's unique life in an extremely cold environment and for determining the effect of algae through the reduction of surface albedo. Here we present the spatial distribution of red snow algae on the Harding Icefield, Alaska retrieved from a satellite image. Field observations on the icefield conducted in August 2001 revealed visible red snow, particularly near the snowline. Field measurements of spectral reflectance on the surface revealed the specific spectral absorption of algal pigments. We found a significant correlation between snow algal biomass and a reflectance ratio of SPOT ( Satellite Probatoire d' Observation de la Terre) satellite band of wavelength 610 - 680 nm to band 500 - 590 nm. Using this relationship between the reflectance ratio and algal biomass, we estimated the distribution and abundance of red snow across the icefield using a SPOT satellite image. The spatial distribution of red snow on the icefield obtained by mapping the reflectance ratio matched field observations across the icefield with more red algal blooms on the continental than the maritime side of the icefield. Area averaged mean carbon content estimated from the red algal biomass for the icefield on the image was 1.2 kg km(-2).
  • Nozomu Takeuchi, Jun Uetake, Koji Fujita, Vladimir B. Aizen, Stanislav D. Nikitin
    ANNALS OF GLACIOLOGY, VOL 43, 2006 43 378 - + 2006年 [査読無し][通常論文]
     
    Snow algae are cold-tolerant algae growing on snow and ice and have been reported on glaciers in many parts of the world. Blooms of snow algae can reduce the surface albedo of snow and ice and significantly affect their melting. In addition, snow algae found in ice cores can be potential indicators of the paleo-environment, making them of great interest both to the biology and the geophysics of glaciers. A snow algal community was investigated in 2002 and 2003 on Akkem glacier in the Russian Altai mountains, where no information on its biological community has previously been available. Five species of snow algae including green algae and cyanobacteria were observed on the glacier. Red snow due to a bloom of algae (Chloromonas sp.) was visually apparent in the snow area during our study periods. The total algal cell-volume biomass on the glacier ranged from 97 to 1156 mu L m(-2), which is equivalent to that reported previously on glaciers in the Himalaya and Alaska. The community structure showed that Mesotaenium berggrenii and/or Ancylonema nordenskioeldii, which are common species on glaciers in the Northern Hemisphere, were dominant in the ice area, while Chloromonas sp. was dominant in the snow area. Such community structures are similar to those on Alaskan and Arctic glaciers but differ from those on Himalayan and Tibetan glaciers, even though the Altai mountains are geographically closer to the Himalaya and Tibet than to Alaska. The difference in algal communities between the Altaic and other glaciers is discussed together with physical and chemical conditions affecting the algae.
  • 三宅 隆之, 植竹 淳, 的場 澄人, 坂井 亜規子, 藤田 耕史, 藤井 理行, 姚 檀棟, 中尾 正義
    日本雪氷学会全国大会講演予稿集 2006 202 - 202 公益社団法人 日本雪氷学会 2006年
  • 植竹 淳, 幸島 司郎, 中澤 文男, 瀬川 高弘, 三宅 隆之, 吉村 義隆, 成田 英器, 藤田 耕二, 竹内 望, 中尾 正義
    日本雪氷学会全国大会講演予稿集 2006 206 - 206 公益社団法人 日本雪氷学会 2006年
  • 竹内 望, 植竹 淳, 瀬川 高弘
    日本雪氷学会全国大会講演予稿集 2006 205 - 205 公益社団法人 日本雪氷学会 2006年
  • Fumio Nakazawa, Fumio Nakazawa, Koji Fujita, Nozumu Takeuchi, Toshiyuki Fujiki, Jun Uetake, Vladimir Aizen, Masayoshi Nakawo
    Journal of Glaciology 51 174 483 - 490 2005年 [査読無し][通常論文]
     
    Reliable chronologies in ice cores and snow pits from many alpine glaciers in latitudes between 60° N and 60° S are often difficult to establish owing to problems with annual-layer counting. Problems arise from melting, wind erosion and the negligible amount of precipitation in some seasons, all of which tend to obscure the seasonal variations in δ18O and chemical concentrations that are typically used to date ice cores. However, alpine glaciers contain many species of pollen grains that peak at particular times of the year. We used the peaks in Betulaceae, Pinus, Artemisia and a combination of Abies and Picea pollen species to determine the four seasonal layers of a snow pit on Belukha glacier in Russia's Altai Mountains. Comparing the pollen-dated profiles with wind and precipitation records allows us to determine where a seasonal layer is missing. Thus, the pollen-dating method described here may be a useful tool to measure the annual snow deposition on alpine glaciers, even when some seasonal layers are eroded by wind or missing due to negligible precipitation.

MISC

  • 青木 輝夫, 的場 澄人, 庭野 匡思, 朽木 勝幸, 谷川 朋範, 竹内 望, 山口 悟, 本山 秀明, 藤田 耕史, 山崎 哲秀, 飯塚 芳徳, 堀 雅裕, 島田 利元, 植竹 淳, 永塚 尚子, 大沼 友貴彦, 橋本 明弘, 石元 裕史, 田中 泰宙, 大島 長, 梶野 瑞王, 足立 光司, 黒﨑 豊, 杉山 慎, 津滝 俊, 東 久美子, 八久保 晶弘, 川上 薫, 木名瀨 健 雪氷 : journal of the Japanese Society of Snow and Ice 83 (2) 169 -191 2021年03月 [査読無し]
     
    北極域で現在急激に進行している温暖化は,海面上昇や大気の遠隔影響を通じて地球規模の環境変動をもたらすと考えられる.グリーンランド氷床の表面融解は様々な不確定性を含み,正確な将来予測を行う上で解明すべき課題となっている.地球温暖化のもとでグリーンランド氷床の大気,雪氷,雪氷微生物がどのように氷床変動に影響するかを明らかにするため,2011 年度から2019 年度にかけてSIGMA 及びSIGMA-II プロジェクトが実施された.また,平行してGRENE,ArCS といった大型の北極研究プロジェクトも実施され,日本のグリーンランド研究が一気に加速される状況になった.本稿ではSIGMA・SIGMA-II プロジェクト及び関連研究課題の成果について(1)大気・雪氷・雪氷微生物の現地観測,(2)アイスコア掘削,(3)衛星観測,(4)数値モデリングのカテゴリーに分けて解説する.さらに,これらの分野における現状の課題,最近開始されたArCS II雪氷課題へのつながり及び人材育成の重要性について述べる.
  • S. Schüpbach, H. Fischer, M. Bigler, T. Erhardt, G. Gfeller, D. Leuenberger, O. Mini, R. Mulvaney, N. J. Abram, N. J. Abram, L. Fleet, M. M. Frey, E. Thomas, A. Svensson, D. Dahl-Jensen, E. Kettner, H. Kjaer, I. Seierstad, J. P. Steffensen, S. O. Rasmussen, P. Vallelonga, M. Winstrup, A. Wegner, B. Twarloh, K. Wolff, K. Schmidt, K. Goto-Azuma, T. Kuramoto, T. Kuramoto, M. Hirabayashi, J. Uetake, J. Uetake, J. Zheng, J. Bourgeois, D. Fisher, D. Zhiheng, C. Xiao, M. Legrand, A. Spolaor, J. Gabrieli, C. Barbante, J. H. Kang, S. D. Hur, S. B. Hong, H. J. Hwang, S. Hong, M. Hansson, Y. Iizuka, I. Oyabu, R. Muscheler, F. Adolphi, F. Adolphi, O. Maselli, J. McConnell, E. W. Wolff Nature Communications 9 (1) 2018年12月01日 [査読無し][通常論文]
     
    © 2018 The Author(s). The Northern Hemisphere experienced dramatic changes during the last glacial, featuring vast ice sheets and abrupt climate events, while high northern latitudes during the last interglacial (Eemian) were warmer than today. Here we use high-resolution aerosol records from the Greenland NEEM ice core to reconstruct the environmental alterations in aerosol source regions accompanying these changes. Separating source and transport effects, we find strongly reduced terrestrial biogenic emissions during glacial times reflecting net loss of vegetated area in North America. Rapid climate changes during the glacial have little effect on terrestrial biogenic aerosol emissions. A strong increase in terrestrial dust emissions during the coldest intervals indicates higher aridity and dust storm activity in East Asian deserts. Glacial sea salt aerosol emissions in the North Atlantic region increase only moderately (50%), likely due to sea ice expansion. Lower aerosol concentrations in Eemian ice compared to the Holocene are mainly due to shortened atmospheric residence time, while emissions changed little.
  • Ryohei Misumi, Yasushi Uji, Yutaka Tobo, Kazuhiko Miura, Jun Uetake, Yoko Iwamoto, Takeshi Maesaka, Koyuru Iwanami Journal of the Meteorological Society of Japan 96 (4) 405 -413 2018年 
    Continuous observations of cloud droplet size distributions (DSDs) in low-level stratiform clouds have been conducted at a height of 458 m from Tokyo Skytree (a 634-m-high broadcasting tower in Tokyo) using a cloud droplet spectrometer. In this report, the characteristics of cloud parameters related to the cloud DSD from June to December 2016 are presented. The mean cloud droplet number concentration (Nc), average diameters, and effective diameters of cloud droplets in non-drizzling clouds were 213 cm−3, 7.3 μm, and 9.5 μm, respectively, which are close to the reported values for continental stratiform clouds. The relationship between liquid water content (LWC; g m−3), Nc (cm−3), and radar reflectivity (Z; mm6 m−3) was estimated as LWC = 0.17 Nc0.50Z0.45, with a coefficient of determination (R2) of 0.93. The observed cloud DSDs were well fitted by a lognormal distribution, and the average median diameter of the fitted DSD was 6.6 μm.
  • 永塚 尚子, 竹内 望, 植竹 淳 月刊地球 37 (3) 72 -82 2015年03月
  • AOKI Teruo, MATOBA Sumito, YAMAGUCHI Satoru, TANIKAWA Tomonori, NIWANO Masashi, KUCHIKI Katsuyuki, ADACHI Kouji, UETAKE Jun, MOTOYAMA Hideaki, HORI Masahiro Bulletin of Glaciological Research (32) 21 -31 2014年08月
  • 三宅 隆之, 植竹 淳, 的場 澄人 雪氷 76 (1) 3 -17 2014年01月
  • 植竹 淳, 瀬川 高弘, 永塚 尚子, 田中 聡太, 竹内 望, 本山 秀明, 青木 輝夫 日本微生物生態学会講演要旨集 2014 125 -125 2014年
  • D. Dahl-Jensen, M. R. Albert, A. Aldahan, N. Azuma, D. Balslev-Clausen, M. Baumgartner, A. M. Berggren, M. Bigler, T. Binder, T. Blunier, J. C. Bourgeois, E. J. Brook, S. L. Buchardt, C. Buizert, E. Capron, J. Chappellaz, J. Chung, H. B. Clausen, I. Cvijanovic, S. M. Davies, P. Ditlevsen, O. Eicher, H. Fischer, D. A. Fisher, L. G. Fleet, G. Gfeller, V. Gkinis, S. Gogineni, K. Goto-Azuma, A. Grinsted, H. Gudlaugsdottir, M. Guillevic, S. B. Hansen, M. Hansson, M. Hirabayashi, S. Hong, S. D. Hur, P. Huybrechts, C. S. Hvidberg, Y. Iizuka, T. Jenk, S. J. Johnsen, T. R. Jones, J. Jouzel, N. B. Karlsson, K. Kawamura, K. Keegan, E. Kettner, S. Kipfstuhl, H. A. Kjær, M. Koutnik, T. Kuramoto, P. Köhler, T. Laepple, A. Landais, P. L. Langen, L. B. Larsen, D. Leuenberger, M. Leuenberger, C. Leuschen, J. Li, V. Lipenkov, P. Martinerie, O. J. Maselli, V. Masson-Delmotte, J. R. McConnell, H. Miller, O. Mini, A. Miyamoto, M. Montagnat-Rentier, R. Mulvaney, R. Muscheler, A. J. Orsi, J. Paden, C. Panton, F. Pattyn, J. R. Petit, K. Pol, T. Popp, G. Possnert, F. Prié, M. Prokopiou, A. Quiquet, S. O. Rasmussen, D. Raynaud, J. Ren, C. Reutenauer, C. Ritz, T. Röckmann, J. L. Rosen, M. Rubino, O. Rybak, D. Samyn, C. J. Sapart, A. Schilt, A. M.Z. Schmidt, J. Schwander, S. Schüpbach, I. Seierstad, J. P. Severinghaus, S. Sheldon, S. B. Simonsen, J. Sjolte, A. M. Solgaard, T. Sowers, P. Sperlich, H. C. Steen-Larsen, K. Steffen, J. P. Steffensen, D. Steinhage, T. F. Stocker, C. Stowasser, A. S. Sturevik, W. T. Sturges, A. Sveinbjörnsdottir, A. Svensson, J. L. Tison, J. Uetake, P. Vallelonga, R. S.W. Van De Wal, G. Van Der Wel, B. H. Vaughn, B. Vinther, E. Waddington, A. Wegner, I. Weikusat, J. W.C. White, F. Wilhelms, M. Winstrup, E. Witrant, E. W. Wolff, C. Xiao, J. Zheng Nature 493 (7433) 489 -494 2013年01月24日 [査読無し][通常論文]
     
    Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North Greenland Eemian Ice Drilling ('NEEM') ice core and show only a modest ice-sheet response to the strong warming in the early Eemian. We reconstructed the Eemian record from folded ice using globally homogeneous parameters known from dated Greenland and Antarctic ice-core records. On the basis of water stable isotopes, NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 ± 4 degrees Celsius above the mean of the past millennium, followed by a gradual cooling that was probably driven by the decreasing summer insolation. Between 128,000 and 122,000 years ago, the thickness of the northwest Greenland ice sheet decreased by 400 ± 250 metres, reaching surface elevations 122,000 years ago of 130 ± 300 metres lower than the present. Extensive surface melt occurred at the NEEM site during the Eemian, a phenomenon witnessed when melt layers formed again at NEEM during the exceptional heat of July 2012. With additional warming, surface melt might become more common in the future. © 2013 Macmillan Publishers Limited. All rights reserved.
  • 植竹 淳, 東 久美子, 本山 秀明 南極資料 56 (1) 57 -67 2012年03月30日 [査読無し][通常論文]
     
    氷床アイスコア中には,鉱物粒子と共に輸送されてきた微生物が含まれる事が知られている.これら微生物の細胞数の計測には,蛍光顕微鏡による直接観察法が用いられるが,細胞数が少ないアイスコア試料では蛍光染色試薬の退色により数を過小評価しやすい一方で,含まれる鉱物などの非特異的な蛍光により過大評価しやすいため,定量的に細胞数を測定する事が困難である.本研究では5種の退色防止試薬から退色が最も少ないもの,19種の蛍光染色試薬から非特異的蛍光との選別が容易な試薬をそれぞれ選出し,細胞壁構造の異なる6種の微生物株を用いて染色選択性を確認し,鉱物の混入による染色への影響を調べた.その結果,退色防止試薬にはEverBrite Mounting Medium(Biotium製),蛍光染色試薬にはYOYO-1(Molecular Probes)が最も適していることがわかり,鉱物が混入する場合は濃度をやや高めに調整することで定量性が高くなる事が示された.
  • 青木輝夫, 朽木勝幸, 庭野匡思, 田中泰宙, 保坂征宏, 橋本明弘, 本山秀明, 兒玉裕二, 植竹淳, 竹内望, 的場澄人, 杉山慎, 山口悟, 本吉弘岐, 岩田幸良, 杉浦幸之助, 八久保晶弘, 堀雅裕, 谷川朋範, 本谷研, 山崎哲秀 日本気象学会大会講演予稿集 (102) 2012年
  • 植竹 淳, 佐藤 和秀, 本山 秀明, 藤井 理行, ノーラン マット, 高橋 修平 雪氷研究大会講演要旨集 2011 (0) 199 -199 2011年 [査読無し][通常論文]
  • 東久美子, 青木周司, 東信彦, 飯塚芳徳, 植竹淳, 川村賢二, 神田啓史, 倉元隆之, 小端拓郎, 笹公和, 佐藤基之, 瀬川高弘, 高村近子, 中澤高清, 平林幹啓, 藤井理行, 藤田秀二, 堀彰, 堀内一穂, 三宅隆之, 三宅隆之, 宮本淳, 本山秀明 極域科学・宙空圏・気水圏・生物・地学シンポジウム講演予稿集(CD-ROM) 2011 2011年
  • 岡本 祥子, 藤田 耕史, 成田 英器, 植竹 淳, 竹内 望, 三宅 隆之, 中澤 文男, Aizen V. B, Nikitin S. A, 中尾 正義 雪氷研究大会講演要旨集 2011 (0) 207 -207 2011年 [査読無し][通常論文]
  • 中澤 文男, 植竹 淳, 陶山 佳久, 金子 亮, 竹内 望, 藤田 耕史, 本山 秀明, 神田 啓史 雪氷研究大会講演要旨集 2011 (0) 55 -55 2011年 [査読無し][通常論文]
  • Uetake Jun, Naganuma Takeshi, Hebsgaard Martin Bay, Kanda Hiroshi, Kohshima Shiro Polar science 4 (1) 71 -80 2010年05月 
    Communities of algae and cyanobacteria on two glaciers in west Greenland (the Qaanaaq and Russel glaciers) were analyzed and compared with the aim of explaining why the Qaanaaq Glacier (in northwestern Greenland) has a dark-colored surface in satellite images whereas the Russel Glacier (in western central Greenland) has a light-colored surface. We found that algal andcyanobacterial communities differed between the glaciers and that the amount of biomass was higher on the colder glacier (Qaanaaq Glacier). The community on the Qaanaaq Glacier was composed mainly of green algae, whereas that on the Russel Glacier was dominated by cyanobacteria. Despite the shorter melting period (due to colder air temperature) for the QaanaaqGlacier, the biovolume of algae and cyanobacteria was 2.35 times higher than that on the Russel Glacier at a similar altitude, suggesting greater primary production on the Qaanaaq Glacier. We discuss the possible effects of temperature, nutrient concentrations, and cryoconite holes (melt-holes in the glacier) on the community structure and productivity of algae and cyanobacteria on each glacier, and consider the influence of the identified differences in algal and cyanobacterial communities on the amount of surface melt.
  • 植竹淳, 植竹淳, 東久美子, 倉元隆之, 本山秀明, 神田啓史 雪氷研究大会講演要旨集 2010 2010年
  • 倉元隆之, 植竹淳, 植竹淳, 東久美子, 平林幹啓, 三宅隆之, 本山秀明 雪氷研究大会講演要旨集 2010 2010年
  • 東久美子, 青木周司, 東信彦, 飯塚芳徳, 植竹淳, 川村賢二, 神田啓史, 倉元隆之, 小端拓郎, 笹公和, 佐藤基之, 瀬川高弘, 高村近子, 中澤高清, 平林幹啓, 藤井理行, 藤田秀二, 堀彰, 堀内一穂, 三宅隆之, 宮本淳, 本山秀明 極域科学・宙空圏・気水圏・生物・地学シンポジウム講演予稿集(CD-ROM) 2010 2010年
  • 伊藤 弘樹, 竹内 望, 幸島 司郎, 植竹 淳 雪氷研究大会講演要旨集 2010 (0) 95 -95 2010年 [査読無し][通常論文]
  • 岡本 祥子, 藤田 耕史, 成田 英器, 植竹 淳, 竹内 望, 三宅 隆之, 中澤 文男, Aizen Vladimir, Nikitin Stanislav, 中尾 正義 雪氷研究大会講演要旨集 2010 (0) 94 -94 2010年 [査読無し][通常論文]
  • 植竹 淳, 金子 亮, 本山 秀明 日本微生物生態学会講演要旨集 (26) 128 -128 2010年
  • 中澤 文男, 植竹 淳, 陶山 佳久, 金子 亮, 竹内 望, 藤田 耕史, 本山 秀明, 神田 啓史 雪氷研究大会講演要旨集 2010 (0) 93 -93 2010年 [査読無し][通常論文]
  • Kumiko Goto-Azuma, Jun Uetake, Kenji Kawamura, Hiroshi Kanda, Takayuki Kuramoto, Takuro Kobashi, Takahiro Segawa, Chiikako Takamura, Motohiro Hirabayashi, Yoshiyuki Fujii, Shuji Fujita, Takayuki Miyake, Hideaki Motoyama, Shuji Aoki, Takakiyo Nakazawa, Nobuhiko Azuma, Motoyuki Sato, Yoshinori Iizuka, Atsushi Miyamoto, Kimikazu Sasa, Akira Hori, Kazuho Horiuchi Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research 2010 4 2010年01月01日 [査読無し][通常論文]
  • Yukimura Kise, Nakai Ryosuke, Kohshima Shiro, Uetake Jun, Kanda Hiroshi, Naganuma Takeshi Polar science 3 (3) 163 -169 2009年11月 
    Organisms living in the Arctic terrains such as Greenland have to deal with low temperature conditions. The mechanisms by which bacteria resist to low temperature are largely unknown; however, a well-known survival strategy of the microorganisms inhabiting the Arctic is spore forming. Moreover, halophilic bacteria are often resistant to various stresses. We have attempted isolation of spore-forming halophilic bacteria from Arctic terrains. We isolated 10 strains of spore-forming halophilic bacteria from the samples collected from a glacial moraine in Qaanaaq, Greenland in July 2007. Identification based on 16S rRNA gene sequence similarities showed that the isolates were closely related to the Oceanobacillus, Ornithinibacillus, Virgibacillus, Gracilibacillus, and Bacillus genera. In addition, the 16S rRNA sequences of some isolates were extremely similar to those of strains from the desert sand in China (100% identity, near full length), the source of the so-called "yellow dust." Previous research indicated that yellow dust had been transported to Greenland by the wind. Our research implies the long-range transportation of these microorganisms to locations such as the Arctic.
  • 植竹 淳, 永塚 尚子, 吉村 義隆 日本微生物生態学会講演要旨集 (25) 76 -76 2009年
  • 中澤 文男, 三宅 隆之, 紺屋 恵子, 田中 基樹, 五十嵐 誠, 植竹 淳 雪氷 : 日本雪氷協會雜誌 70 (5) 507 -509 2008年09月15日
  • 植竹 淳, 長沼 毅, 神田 啓史, 幸島 司郎 日本微生物生態学会講演要旨集 (24) 89 -89 2008年
  • 佐藤 和秀, 植竹 淳, 高橋 修平, 佐藤 研吾, 山崎 哲秀, 高橋 昭好, Nolan Matt, 五十嵐 誠, 藤井 理行 日本雪氷学会全国大会講演予稿集 2006 (0) 105 -105 2006年 [査読無し][通常論文]
  • SAKAI Akiko, MATSUDA Yoshihiro, FUJITA Koji, MATOBA Sumito, UETAKE Jun, SATOW Kazuhide, DUAN Keqin, PU Jianchen, NAKAWO Masayoshi, YAO Tandong Bulletin of glaciological research 23 23 -32 2006年01月01日
  • UETAKE Jun, SAKAI Akiko, MATSUDA Yoshihiro, FUJITA Koji, NARITA Hideki, MATOBA Sumito, DUAN Keqin, NAKAWO Masayoshi, YAO Tandong Bulletin of glaciological research 23 85 -93 2006年01月01日
  • 三宅 隆之, 中澤 文男, 河野 美香, 植竹 淳, 鈴木 啓助, 亀田 貴雄, 藤井 理行, 中尾 正義, 大田 啓一 Bulletin of glaciological research 22 81 -87 2005年03月01日
  • 三宅 隆之, 藤井 理行, 中澤 文男, 植竹 淳, 竹内 望, 藤田 耕史, 中尾 正義 日本雪氷学会全国大会講演予稿集 2005 (0) 147 -147 2005年 [査読無し][通常論文]
  • 植竹 淳, 幸島 司郎, 中澤 文男, 竹内 望, 三宅 隆之, 藤田 耕史, 中尾 正義 日本雪氷学会全国大会講演予稿集 2005 (0) 148 -148 2005年 [査読無し][通常論文]
  • 竹内 望, Dial Roman, 幸島 司郎, 瀬川 高弘, 植竹 淳 日本雪氷学会全国大会講演予稿集 2005 (0) 37 -37 2005年 [査読無し][通常論文]
  • Takeuchi Nozomu, Takahashi Akiyoshi, Uetake Jun, Yamazaki Tetsuya, Aizen Vladimir B., Joswiak Daniel, Surazakov Arzhan, Nikitin Stanislav Polar meteorology and glaciology 18 121 -133 2004年11月 
    A 171m deep ice core from the surface to the bottom has been successfully drilled on the West Belukha snow-firn Plateau in the Russian Altai Mountains in the summer of 2003. The drill system used in this project was an electro-mechanical drill with a barrel 135cm long and 9.5cm in inner diameter manufactured by Geo Tecs Co., Japan. The maximum core length for a drilling run is 55cm. It took 87.5 hours in actual working time of 7 working days to drill the core down to the bottom of the glacier. The total number of drilling runs was 325. The mean length of the drilled core was 48.6cm. Most of the cores were not brittle and had a good cylindrical shape. High air temperature above the melting point in the drilling shelter caused some trouble in drilling. One of the major troubles was slip of cutters due to adhesion of cutting tips to the cutters and shoes.
  • 植竹 淳 雪氷 66 (1) 89 -93 2004年01月15日
  • 植竹 淳, 幸島 司郎, 竹内 望, 坂井 亜規子, 松田 好弘 日本雪氷学会全国大会講演予稿集 2004 (0) 103 -103 2004年 [査読無し][通常論文]
  • Nakazawa Fumio, Fujita Koji, Uetake Jun, Kohno Mika, Fujiki Toshiyuki, Serguei M. Arkhipov, Kameda Takao, Suzuki Keisuke, Fujii Yoshiyuki, 亀田 貴雄 Journal of Geophysical Research 109 (4) F04001 2004年
  • 亀田 貴雄, 藤井 理行, 鈴木 啓助, 河野 美香, 中沢 文男, 植竹 淳, SAVATYUGIN Lev M., ARKHIPOV Serguei M., PONOMAREV Ivan A., MIKHAILOV Nikolay N. Bulletin of glaciological research 21 65 -69 2004年01月01日
  • Suzuki Keisuke, Kameda Takao, Kohno Mika, Nakazawa Fumio, Uetake Jun, Fujii Yoshiyuki, 亀田 貴雄 Polar meteorology and glaciology 16 140 -148 2002年11月 
    Meteorological observations were carried out on Sofiyskiy Glacier from July 7 to 17, 2001. Air temperature, relative humidity, wind direction, wind speed, atmospheric pressure and global radiation were measured with automatic instruments every ten minutes. Snow surface height was measured using a stake installed in the surface snow several times a day. The net gain of snow surface during the observation period was 268 mm. In the first half of the observation period, air temperature exceeded 3°C during the daytime, but air temperature never became positive during the latter half of the observation period. The heat balance was examined from the meteorological data. The values of estimated snowmelt and observed snowmelt correspond almost exactly.
  • 藤井 理行, 亀田 貴雄, 西尾 文彦, 鈴木 啓助, 河野 美香, 中澤 文男, 植竹 淳, SAVATYUGIN Lev M., ARKHIPOV Serguei M., PONOMAREV lvan A., MIKHAILOV Nikolay N. Bulletin of glaciological research 19 53 -58 2002年02月01日
  • T Shiraiwa, S Kohshima, R Uemura, N Yoshida, S Matoba, J Uetake, MA Godoi ANNALS OF GLACIOLOGY, VOL 35 35 84 -90 2002年 [査読無し][通常論文]
     
    A 45.97 in long ice core was recovered in the accumulation area of Glaciar Tyndall (50degrees59'05" S, 73degrees31'12" W, 1756 in a.s.l.), Campo de Hielo Patagonico Sur (southern Patagonia icefield), during December 1999. The firn core was subjected to visual stratigraphic observation and bulk density measurements in the field, and later to analyses of water isotopes (delta(18)O, deltaD), major dissolved ions and snow algal biomass. The drillhole remained dry down to about 43 in depth, where a water-soaked layer appeared. Seasonal cycles were found for delta(18)O, deltaD and the D-excess, although the amplitudes of the cycles decreased with depth. Major dissolved ions (Na+, K+, Mg2+, Ca2+, Cl-, SO42-) and algal biomass exhibit rapid decreases in the upper 3 in, probably due to meltwater elution. Annual increments defined by the 518 0 and D-excess peaks suggest that the minimum net accumulation rates at this location were 17.8 in a(-1) in 1997/98-1998/99 and > 11.0 in a(-1) in 1998/99-1999/2000. These are much higher values than those previously obtained from past ice-core studies in Patagonia, but are of the same order of magnitude as those predicted from various observations in ablation areas of Patagonian glaciers.

共同研究・競争的資金等の研究課題

  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2023年09月 -2026年03月 
    代表者 : 當房 豊, 吉田 淳, 植竹 淳, 大畑 祥, 足立 光司
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2022年04月 -2026年03月 
    代表者 : 鏡味 麻衣子, 三木 健, 竹内 望, 植竹 淳, 村上 正志, 瀬川 高弘
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2022年04月 -2025年03月 
    代表者 : 植竹 淳
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2019年04月 -2024年03月 
    代表者 : 竹内 望, 植竹 淳, 瀬川 高弘, 米澤 隆弘, 幸島 司郎, 服部 祥平
     
    当初2020年度に予定していたアラスカ氷河の野外調査は,2021年度に予算繰り越しを行い実施する計画を立てていた.しかしながら,新型コロナ感染症の流行は収まることはなく,2021年度も海外野外調査を実施することはできなかった.その代わり,国内の積雪表面を対象に野外調査を実施し,さらに過去に採取された試料の分析をすすめた.国内の積雪では,雪氷藻類の繁殖が進んだ表面には,藻類お捕食者となるクマムシやワムシも多く存在することを発見し,論文で発表した(Ono et al., 2021).またアラスカの赤雪の分析を進めたところ,赤雪細胞の表面に大量の多糖類が分泌されていることが明らかになり,この多糖類が細胞の凝集効果を持っていることが明らかになり,論文に発表した(Folika et al., 2020).氷河表面の暗色化の原因物質の一つ,クリオコナイトについても過去に採取したサンプルの分析を進めた.クリオコナイトの粒構造分析を行なった結果,内部では嫌気条件となっており,そこに繁殖する嫌気的細菌類が特に窒素循環に重要な役割を果たしていることが明らかになった(Segawa et al., 2020).中央アジアの氷河ではアルベドの時空間変動が,クリオコナイトの表面量の変動で説明できることが明らかになった(Yue et al., 2020). さらに,クリオコナイトには放射性元素が特異的に濃縮していることも明らかになった(Baccolo et al., 2020).2021年度に繰り越した予算は,研究遂行に必須である雪氷試料の化学成分を分析するイオンクロマトグラフィーが故障したため,一部を新しく購入するために利用した.
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2016年04月 -2018年03月 
    代表者 : 辻 雅晴, 辻本 惠, 植竹 淳
     
    本研究課題では日本の南極観測の拠点である東オングル島から異なる季節(12月(春)と2月(秋))にそれぞれ同じ地点から採取された土壌における菌類の多様性の変化についてillumina社製の次世代シーケンサーMiseqを利用してその解明を試みた。 次世代 シーケンサーで得られた配列を解析した結果、菌類では、128の集団 に分類することが出来た。この集団を詳細に解析し春と秋の季節の違いによる菌類相お変化を調べたところ、季節によって菌類相が大きく変化することが世界で初めて明らかにすることが出来た。
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2014年04月 -2018年03月 
    代表者 : 幸島 司郎, 竹内 望, 藤田 耕史, 吉村 義隆, 本郷 裕一, 瀬川 高弘, 植竹 淳, 近藤 伸二
     
    世界各地の氷河で採取した微生物の遺伝子分析と地域間比較により、氷河融解を加速する汚れ物質(クリオコナイト)形成に関係するバクテリアやシアノバクテリアの地理的分布や汚れ物質内での分布、氷河動物と共生するバクテリアの存在が初めて明らかになった。また、生物によるアルベド改変過程を組み込んだ氷河変動モデルを改良するために、クリオコナイトが氷河表面に形成する縦穴(クリオコナイトホール)の発達や崩壊を精度良く表現できる数値計算モデルを構築した。
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2015年04月 -2017年03月 
    代表者 : 植竹 淳
     
    昨年度に行ったケニア山の氷河に生息している微生物の多様性に関する予備調査を踏まえ、氷河上での不均一性や同一地点での経年変化、また氷河周辺土壌に与える影響を評価するために、ルイス氷河において観測機器の回収、観測、サンプルの採取を行った。現地に設置したインターバルカメラの結果から、本氷河の融解による表面低下が非常に大きいことがわかり、設置期間中の2017年2月に氷河中流部の岩が露出し、ルイス氷河が上下に分断する様子を記録することができた。 DNA分析の結果、同氷河が隣国のウガンダ、ルウェンゾリ山の氷河よりも中国、天山山脈や北極、スバールバードの氷河に生息している微生物の群集構造に近いことがわかり、氷河上の微生物が全球的な粒子の移動と循環の影響を受けている可能性を示した。
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2011年04月 -2016年03月 
    代表者 : 青木 輝夫, 本山 秀明, 竹内 望, 的場 澄人, 堀 雅裕, 八久保 晶弘, 山口 悟, 田中 泰宙, 岩田 幸良, 杉浦 幸之助, 兒玉 裕二, 藤田 耕史, 朽木 勝幸, 庭野 匡思, 保坂 征宏, 橋本 明弘, 谷川 朋範, 田中 泰宙, 植竹 淳, 永塚 尚子, 杉山 慎, 本吉 弘岐, 下田 星児, 本谷 研
     
    グリーンランド氷床上での現地観測から、涵養域ではアルベド低下に対するブラックカーボン(BC)等積雪不純物の寄与は小さく、積雪粒径増加効果の方が大きいことが分かった。また2012年7月の顕著な表面融解には下層雲からの長波放射が効いていた。消耗域では表面の不純物中に微生物が大量に含まれ、アルベド低下へ大きく寄与していた。衛星観測から2000年以降の氷床表面アルベドの低下原因を解析した結果、涵養域では積雪粒径の経年増加が主要因で、消耗域では裸氷域と微生物を含む暗色域の拡大が原因であった。内陸域で深さ223mの氷床コアを掘削し、その解析からBC濃度は1920-30年に現在の数倍程度高いことが分かった。
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2010年04月 -2016年03月 
    代表者 : 東 久美子, 川村 賢二, 藤田 秀二, 植竹 淳, 本山 秀明, 平林 幹啓, 小端 拓郎, 高村 近子, 倉元 隆之, 瀬川 高弘, 青木 周司, 東 信彦, 飯塚 芳徳
     
    国際深層氷床掘削プロジェクトに参加し、グリーンランド氷床コアを掘削・分析することで、最終間氷期や完新世初期の温暖期と最終氷期の急激な温暖化イベント発生時の気候・環境変動を高時間分解能で復元し、温暖化が氷床変動や環境変動に及ぼす影響を研究した。その結果、最終間氷期の最温暖期は現在よりも気温が8℃±4℃高く、北グリーンランドで顕著な氷床表面融解が起こり、氷床の厚さが400±250m減少したことが示された。グリーンランドの氷の減少量は予想よりも小さく、最終間氷期における海面上昇には南極氷床の縮小が寄与したことが示唆された。また、温暖化に伴う大気・物質循環、微生物活動、海水温の変化が明らかになった。
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2013年04月 -2015年03月 
    代表者 : 植竹 淳
     
    赤道直下のアフリカ、ルウェンゾリ山の氷河(ウガンダ)は、大幅な縮小が報告され、近い将来に消滅が予測されている。氷河の表面は1年間で最大で161cm低下しており、低下量は氷河表面が黒くなり反射率が低くなるほど顕著であることがわかった。この氷河の黒色化には、氷河上で生育するコケ植物の塊(GMGA)の分布が関連しており、日射などにより氷河の表面温度が高くなることで、主構成種のCeratodon purpureusの増殖が促されていることが示唆された。
  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2008年 -2010年 
    代表者 : 植竹 淳
     
    南極アイスコア中に含まれる微生物は、氷期間氷期サイクルなどの過去の気候変動と連動して変化している可能性があるため、計244サンプルを解析した。球状のバクテリアの濃度は南極外から飛来してきた鉱物粒子量が非常に多い層と一致する事から、鉱物粒子と共に飛来してきたバクテリアである可能性が考えられる。また、糸状菌様の粒子は特に鉱物粒子が多い層では無いため、風送微粒子と共に飛来してきた可能性は低いと考えられる。


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