Updated on 2024/12/07

写真a

 
YOSHITAKE, Shinpei
 
Affiliation
Faculty of Education and Integrated Arts and Sciences, School of Education
Job title
Associate Professor
Degree
博士(学術) ( 2008.03 広島大学 )

Research Experience

  • 2021.04
    -
    Now

    Waseda University   Faculty of Education and Integrated Arts and Sciences   Associate Professor

  • 2019.04
    -
    2021.03

    Waseda University   Faculty of Education and Integrated Arts and Sciences   Assistant Professor

  • 2012.07
    -
    2019.03

    Gifu University   River Basin Research Center   Research Associate

  • 2012.04
    -
    2019.03

    Waseda University   Research Institute for Science and Engineering   Adjunct Researcher

  • 2009
    -
    2012.03

    Waseda University   Faculty of Education and Integrated Arts and Sciences   JSPS Research Fellow (PD)

  • 2008.04
    -
    2009.03

    Waseda University   Faculty of Education and Integrated Arts and Sciences   JSPS Research Fellow (PD)

  • 2007.04
    -
    2008.03

    Hiroshima University   Graduate School of Biosphere Sciences   JSPS Research Fellow (DC2)

▼display all

Education Background

  • 2005.04
    -
    2008.03

    Hiroshima University   Graduate School of Biosphere Science   Department of Environmental Dynamics and Management  

  • 2003.04
    -
    2005.03

    Hiroshima University   Graduate School of Biosphere Science   Department of Environmental Dynamics and Management  

  • 1999.04
    -
    2003.03

    Hiroshima University   Faculty of Integrated Arts and Sciences  

Committee Memberships

  • 2020.12
    -
    2023.03

    環境省「バイオ炭施用拡大による吸収源検討会」  有識者委員

  • 2021.04
    -
    2022.03

    日本生態学会  大会企画委員会ポスター部会長

  • 2019.04
    -
    2022.03

    日本生態学会  大会企画委員会ポスター部会員

  • 2017.01
    -
    2019.03

    日本生態学会中部地区会  会計幹事

Professional Memberships

  •  
     
     

    The Ecological Society

  •  
     
     

    日本地球惑星科学連合

Research Areas

  • Ecology and environment

Research Interests

  • biochar

  • Nitrogen cycle

  • Carbon cycle

  • Ecological stoichiometry

  • Ecological succession

  • Desert ecosystems

  • Ecosystem development

  • Ecosystem ecology

  • Soil microorganisms

  • Substrate limitation

  • Matter Cycle

  • Phospholipid fatty acid analysis

  • Microbial respiration

  • Microbial biomass

  • Microbial community structure

▼display all

Awards

  • 若手ポスター発表優秀賞

    2024.09   日本土壌肥料学会   森林土壌に施用されたバイオチャーの炭素・窒素吸着と炭素隔離効果

    Winner: 三森大暉, 樽見知樹, 橋本麗優, 友常満利, 吉竹晋平

  • ポスター優秀賞

    2024.03   日本生態学会   LCAを用いた森林でのバイオチャーによる炭素隔離の評価 ~作出から生態系応答まで~

    Winner: 樽見知樹, 友常満利, 進藤恵太, 依田真由, 吉竹晋平

  • ポスター賞

    2024.02   第10回東京女子医科大学・早稲田大学研究交流セミナー   Life-Cycle Assessmentを用いた森林でのバイオチャーによる炭素隔離の評価 ~作出から生態系応答まで~

    Winner: 樽見知樹, 友常満利, 進藤恵太, 依田真由, 吉竹晋平

  • ポスター優秀賞

    2022.03   日本生態学会   冷温帯コナラ林における非切断細根呼吸の日変化パターン

    Winner: 今吉健斗, 塩手文也, 吉竹晋平

  • ポスター賞

    2018.11   日本生態学会中部地区会   金華山の常緑広葉樹林における生態系純生産量の推定

    Winner: 鈴木莉央奈, 曹若明, 陳思宇, 吉竹晋平, 大塚俊之

  • Ecological Research Award

    2018.03   The Ecological Society of Japan   Seasonality of leaf litter and leaf area index data for various tree species in a cool-temperate deciduous broad-leaved forest, Japan, 2005-2014

    Winner: S. Nagai, K.N. Nasahara, S. Yoshitake, T.M. Saitoh

  • The Poster Award

    2016.12   The Chubu Branch of Ecological Society of Japan  

    Winner: C. Asai, S. Yoshitake, T. Ohtsuka

  • The Excellent Poster Award

    2013.03   The Ecological Society of Japan  

    Winner: A. Mishima, M. Tomotsune, S. Yoshitake, H. Koizumi

  • The Excellent Poster Award

    2012.03   The Ecological Sociery of Japan and East Asian Federation of Ecological Societies   Diurnal and seasonal variations of soil, heterotrophic and root respiration estimated by automatic open/close chamber and trenching method

    Winner: M. Tomotsune, T. Anzai, S. Yoshitake, H. Koizumi

  • The Excellent Poster Award

    2011.03   The Ecological Society of Japan  

    Winner: Y. Sekine, S. Yoshitake, H. Koizumi

  • The Best Poster Award

    2010.03   The Ecological Society of Japan  

    Winner: M. Tomotsune, S. Yoshitake, Y. Sekine, H. Koizumi

  • Best Presentation Award

    2008.12   National Institute of Polar Research   Photosynthetic characteristics of biological soil crusts in a High Arctic glacier foreland in Ny-Ålesund, Svalbard

    Winner: S. Yoshitake, M. Uchida, H. Koizumi, H. Kanda, T. Nakatsubo

  • The Excellent Poster Award

    2008.03   The Ecological Society of Japan  

    Winner: T. Nakao, A. Sasaki, Y. Hagimori, S. Yoshitake, T. Nakatsubo

  • Student Award

    2008.03   Hiroshima University  

    Winner: YOSHITAKE Shinpei

  • The Excellent Poster Award

    2007.03   The Ecological Society of Japan  

    Winner: S. Yoshitake, T. Nakatsubo

  • Excellent Hiroshima University Student scholarship

    2007.03   Hiroshima University  

    Winner: YOSHITAKE Shinpei

  • Poster Session Award

    2007.02   Seventh International Conference on Global Change: Connection to the Arctic   Soil respiration in a High Arctic glacier foreland in Ny-Ålesund, Svalbard: Is it limited by low carbon and nitrogen availability?

    Winner: S. Yoshitake, M. Uchida, T. Nakatsubo, H. Koizumi, H. Kanda

  • The Excellent Poster Award

    2006.03   The Ecological Sociery of Japan  

    Winner: N. Kan, M. Uchida, S. Yoshitake, H. Kanda, H. Koizumi

  • The Best Poster Award

    2006.03   The Ecological Society of Japan  

    Winner: Y. Funatsu, S. Yoshitake, M. Fujiyoshi, T. Nakatsubo

  • The Best Poster Award

    2005.03   The Ecological Society of Japan  

    Winner: S. Yoshitake, M. Uchida, H. Kanda, T. Nakatsubo

  • The Excellent Poster Award

    2004.08   The Ecological Society of Japan  

    Winner: S. Yoshitake, T. Nakatsubo

▼display all

 

Papers

  • Carbon dynamics of organic layer in three forest stands dominated by different tree species

    Ryuta Nishigai, Shinpei Yoshitake

    Journal of Forest Research     1 - 7  2024.05  [Refereed]

    Authorship:Last author, Corresponding author

    DOI

  • Biomass recovery of coastal young mangrove plantations in Central Thailand

    Toshiyuki Ohtsuka, Suthathip Umnouysin, Vilanee Suchewaboripont, Nada Yimatsa, Chadtip Rodtassana, Morimaru Kida, Yasuo Iimura, Shinpei Yoshitake, Nobuhide Fujitake, Sasitorn Poungparn

    Scientific Reports   14 ( 1 )  2024.05  [Refereed]

     View Summary

    Abstract

    Around one-third of the world’s most carbon-rich ecosystems, mangrove forests, have already been destroyed in Thailand owing to coastal development and aquaculture. Improving these degraded areas through mangrove plantations can restore various coastal ecosystem services, including CO2 absorption and protection against wave action. This study examines the biomass of three coastal mangrove plantations (Avicennia alba) of different ages in Samut Prakarn province, Central Thailand. Our aim was to understand the forest biomass recovery during the early stages of development, particularly fine root biomass expansion. In the chronosequence of the mangrove plantations, woody biomass increased by 40% over four years from 79.7 ± 11.2 Mg C ha-1 to 111.7 ± 12.3 Mg C ha−1. Fine root biomass up to a depth of 100 cm was 4.47 ± 0.33 Mg C ha−1, 4.24 ± 0.63 Mg C ha−1, and 6.92 ± 0.32 Mg C ha−1 at 10, 12, and 14 year-old sites, respectively. Remarkably, the fine root biomass of 14-year-old site was significantly higher than those of the younger sites due to increase of the biomass at 15–30 cm and 30–50 cm depths. Our findings reveal that the biomass recovery in developing mangrove plantations exhibit rapid expansion of fine roots in deeper soil layers.

    DOI

  • The Nitrogen Cycle of a Cool-Temperate Deciduous Broad-Leaved Forest

    Ruoming Cao, Siyu Chen, Shinpei Yoshitake, Takeo Onishi, Yasuo Iimura, Toshiyuki Ohtsuka

    Forests   15 ( 4 ) 725  2024.04  [Refereed]

    DOI

  • Decrease in Inorganic Nitrogen and Net Nitrogen Transformation Rates with Biochar Application in a Warm-Temperate Broadleaved Forest

    Natsumi Yasuki, Wakana Saso, Hiroshi Koizumi, Yasuo Iimura, Toshiyuki Ohtsuka, Shinpei Yoshitake

    Forests   15 ( 3 ) 572 - 572  2024.03  [Refereed]

    Authorship:Last author, Corresponding author

     View Summary

    Changes in soil nutrient dynamics after biochar application may affect indirect carbon sequestration through changes in plant productivity in forest ecosystems. In the present study, we examined the effects of woody biochar application on soil nitrogen (N) cycling over 8 months in a warm-temperate deciduous broad-leaved forest. Mineral soil samples were collected from the plots treated with different biochar applications (0, 5, and 10 Mg ha−1), and the soil inorganic N concentration was measured. Net mineralization and nitrification rates were determined in each plot using the resin–core method. Soil temperature and water content did not change significantly, but the pH increased significantly following biochar application. Soil inorganic N concentrations (NH4+ and NO3−) and net N transformation rates (mineralization and nitrification rates) were significantly reduced. Microbial biomass and the nitrification ratio (the ratio of nitrification rate to mineralization rate) were unchanged, indicating that the decrease in soil inorganic N concentration was due to the reduced mineralization rate. Adsorption of substrates (from organic matter) by the applied biochar is the most likely reason for the reduction in the N mineralization rate. The results indicate that biochar application does not necessarily stimulate N transformation, which will affect indirect carbon sequestration.

    DOI

  • Canopy Phenology and Meteorology Shape the Seasonal Dynamics in Hydrological Fluxes of Dissolved Organic Carbon in an Evergreen Broadleaved Subtropical Forest in Central Japan

    Siyu Chen, Ruoming Cao, Shinpei Yoshitake, Toshiyuki Ohtsuka

    Forests   14 ( 5 ) 1013 - 1013  2023.05  [Refereed]

     View Summary

    Seasonal variabilities in hydrological fluxes of dissolved organic carbon (DOC) and their driving factors in the evergreen broad-leaved forest are inadequately understood. To aid this understanding, we conducted a three-year study to examine seasonal changes in DOC concentration and flux in throughfall, stemflow, and litter leachate in an evergreen broad-leaved subtropical forest in central Japan. We specifically addressed (1) how DOC in different hydrological fluxes vary on a monthly to seasonal basis, and (2) how canopy phenology and meteorology shape the DOC concentration and flux of throughfall, stemflow, and litter leachate trends in this evergreen forest. Clear seasonal changes were found in throughfall and stemflow DOC concentration but not in litter leachate DOC concentration; the highest throughfall DOC concentrations were observed in spring (10.03 mg L−1 in 2017 and 9.59 mg L−1 in 2018, respectively) and the highest stemflow DOC concentrations were observed in summer (13.95 mg L−1 in 2017 and 16.50 mg L−1 in 2018, respectively). Correlation analysis revealed the monthly throughfall DOC concentration to be positively related to the dry weight of fallen leaves (r = 0.72, p < 0.05) and flowers (r = 0.91, p < 0.05). In addition, Random Forest models predicted that the dry weight of flowers was a primary driver of throughfall DOC concentration and that the DOC concentrations of stemflow and litter leachate were constrained by the throughfall DOC concentration. DOC fluxes in different hydrological flux were significantly positive related to bulk precipitation amounts and temperature. Moreover, the throughfall DOC concentration had a considerable effect on throughfall and litter leachate DOC fluxes. Over 75% of annual net tree-DOC (throughfall + stemflow) fluxes and more than 70% of the annual litter leachate DOC fluxes were produced in the flowering season. Thus, we speculated that the seasonal phenological canopy changes (leaf emergence, fallen leaves, flowering, and pollen) and the sufficient rainfall had great impacts on the amount and quality of DOC concentrations in the evergreen forest; and, furthermore, that the DOC from different forest hydrological fluxes was a significant fraction of the carbon that accumulates in soils.

    DOI

  • Biometric-Based Net Primary Production (NPP) and the Effects of a Masting Event on Production Allocation in a Secondary Lucidophyllous Forest in Central Japan

    Toshiyuki Ohtsuka, Riona Suzuki, Siyu Chen, Ruoming Cao, Shinpei Yoshitake, Miyuki Kondo, Shogo Kato

    Forests   14 ( 1 ) 108 - 108  2023.01  [Refereed]

     View Summary

    Lucidophyllous (evergreen broad-leaved) forests are the dominant forests in human-dominated subtropical/warm-temperate regions in East Asia. Biometric-based estimates of net primary production (NPP) were conducted in a secondary lucidophyllous forest on Mt. Kinka (35°26′ N, 136°47′ E) near the northern limit of their distribution in central Japan for three years, including the masting event. The forest stand mainly consists of Castanopsis cuspidata (Thunb.) Schottky and Cleyera japonica Thunb. in the canopy and subtree layers, respectively. In 2018, the total NPP of the masting year was 14.53 ± 2.03 ton ha−1 yr−1, including woody NPP (above: 2.63 ± 0.35 ton ha−1 yr−1; below: 0.57 ± 0.08 ton ha−1 yr−1), foliage NPP (4.07 ± 0.23 ton ha−1 yr−1), reproductive NPP (4.81 ± 0.77 ton ha−1 yr−1), and fine root production (Pfr) (2.46 ± 1.84 ton ha−1 yr−1). Pfr and belowground production comprised 16.9% and 20.9%, respectively, of the total NPP. The nut production of C. cuspidata in 2018 (4.31 ± 0.75 ton ha−1 yr−1) was significantly higher than that in 2017 (0.77 ± 0.13 ton ha−1 yr−1) and 2019 (0.23 ± 0.06 ton ha−1 yr−1). No significant change was observed for the three years of foliage NPP and total NPP without Pfr. However, the woody NPP in 2018 (3.20 ± 0.43) was lower than in 2017 (5.37 ± 0.33 ton ha−1 yr−1) and 2019 (4.71 ± 0.38 ton ha−1 yr−1). This suggests that nut production in the masting years compensated by decreasing woody production in the Castanopsis forest.

    DOI

  • Organic carbon stock and composition in 3.5-m core mangrove soils (Trat, Thailand)

    Morimaru Kida, Ikumi Watanabe, Kazutoshi Kinjo, Miyuki Kondo, Shinpei Yoshitake, Mitsutoshi Tomotsune, Yasuo Iimura, Suthathip Umnouysin, Vilanee Suchewaboripon, Sasitorn Poungparn, Toshiyuki Ohtsuka, Nobuhide Fujitake

    Science of The Total Environment     149682 - 149682  2021.08  [Refereed]  [International coauthorship]

    DOI

  • Photosynthetic response of young oaks to biochar amendment in field conditions over 3 years

    Yumina Tanazawa, Mitsutoshi Tomotsune, Takeshi Suzuki, Hiroshi Koizumi, Shinpei Yoshitake

    Journal of Forest Research   26 ( 2 ) 116 - 126  2021.03  [Refereed]

    Authorship:Last author, Corresponding author

     View Summary

    Amendment by biochar made by thermal degradation of biomass is expected to enhance carbon sequestration through stimulating carbon assimilation by plants. We clarified the effect of biochar amendment on the photosynthesis of trees in forest ecosystems. Biochar was applied to young oak trees (Quercus serrata) in temperate deciduous forest at rates of 0, 5, 10 and 20 Mg ha−1 in four plots (C0, C5, C10, and C20). The variation in photosynthetic parameters (the maximum photosynthetic rate: Pmax, maximum carboxylation rate: Vcmax and the potential rate of electron transport: Jmax) and leaf traits (the stomatal conductance: gc, leaf mass per area (LMA) and leaf nutrient concentrations) were examined every month during the growing seasons for 3 years. Pmax generally increased in C5 and C10 and did not increase in C20. Similarly, Vcmax and Jmax increased in C5 and C10 and correlated significantly positively with Pmax, suggesting that biochar amendment basically increased the photosynthetic rate through improvements in physiological activities but that there was a maximum useful dosage. We also found that gc, LMA and leaf nutrient (N, Mg, and S) showed significant positive correlations with Pmax, indicating that an increase in photosynthetic rates would be supported by these leaf traits. However, stimulation of photosynthesis became smaller year by year, indicating that the effects of biochar amendment faded gradually. We concluded that biochar amendment basically improved the photosynthesis of oak trees in the forest through the change of all gc, LMA and leaf nutrient concentrations but declined yearly.

    DOI

  • Comparison of inter-annual variation in net primary production among three forest types in the same region over 7 years

    Yuki Kato, Mitsutoshi Tomotsune, Fumiya Shiote, Yuta Koyama, Hiroshi Koizumi, Shinpei Yoshitake

    Journal of Forest Research   26 ( 2 ) 110 - 115  2021.03  [Refereed]

    Authorship:Last author, Corresponding author

    DOI

  • Organic and inorganic nitrogen deposition in an urban evergreen broad-leaved forest in central Japan

    Ruoming Cao, Siyu Chen, Shinpei Yoshitake, Toshiyuki Ohtsuka

    Atmospheric Pollution Research   12 ( 2 ) 488 - 496  2021.02  [Refereed]

    DOI

  • Effects of the Application of Biochar to Plant Growth and Net Primary Production in an Oak Forest

    Toshiyuki Ohtsuka, Mitsutoshi Tomotsune, Masaki Ando, Yuki Tsukimori, Hiroshi Koizumi, Shinpei Yoshitake

    Forests   12 ( 2 ) 152 - 152  2021.01  [Refereed]

    Authorship:Last author

     View Summary

    Few studies have evaluated the application of biochar to forest ecosystems and their responses under field conditions. We manually spread grounded biochar on the forest floor, at rates of 0 (control), 5, and 10 Mg ha−1 (C0, C5 and C10, respectively), of an oak forest in central Japan to test the effects of biochar on tree growth and productivity. The relative growth rate of the diameter at breast height (dbh) of canopy oak trees (dbh > 20 cm) significantly increased in C10 compared with that of the control (C0), but not in C5, in the second to third years after application. Despite the increasing growth rate of canopy trees, foliage production (NPPF) and woody production (NPPW) did not respond to biochar application. Conversely, the production of reproductive organs (NPPR, mainly oak acorns) increased in line with the biochar application rate gradients (1.04 ± 0.09 Mg ha−1 yr−1 in C0, 1.30 ± 0.08 Mg ha−1 yr−1 in C5, and 1.47 ± 0.13 Mg ha−1 yr−1 in C10). Since the contribution of NPPR to total NPP was fairly small, there were no significant differences in total NPP (=NPPW + NPPF + NPPR) for C5 (14.57 ± 0.20 Mg ha−1 yr−1) or C10 (16.11 ± 0.73 Mg ha−1 yr−1) compared with the control (15.07 ± 0.48 Mg ha−1 yr−1).

    DOI

  • Composite effects of temperature increase and snow cover change on litter decomposition and microbial community in cool‐temperate grassland

    Shinpei Yoshitake, Nobuhiko Suminokura, Toshiyuki Ohtsuka, Hiroshi Koizumi

    Grassland Science   67 ( 4 ) 315 - 327  2020.12  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    Abstract

    We aimed to clarify the individual and interactive effects of temperature increase during snow‐free seasons and snow depth change (increase/decrease) on litter decomposition and microbial community in cool‐temperate semi‐natural grassland. We conducted a 2‐year in situ composite warming experiment comprising temperature increase (ca. 2°C) using infrared heaters during snow‐free seasons and manual snow depth manipulation (±50% in snow depth) in Japanese grassland. Changes in litter mass remaining and litter carbon‐to‐nitrogen ratio (C/N ratio) were assessed by litter bag methods. Microbial biomass and community structure were determined by phospholipid fatty acid analysis. Litter decomposition constant (k) was low in the plots with temperature increase during snow‐free seasons (0.56) and with less snow cover (0.57), but combining these two treatments resulted in acceleration of decomposition (k = 0.70); probably, decreased decomposition in the cold climate of early spring resulting from advanced snow melting was compensated for by higher temperature. Differences in mass loss among the treatments were well explained by litter C/N, microbial biomass and microbial community structure. The plots with a high mass loss showed lower litter C/N ratio, larger microbial biomass and different microbial community structure comparing to the plots with low mass loss. Our results showed the complex responses of litter decomposition to summer and winter climate change and combination of less snow cover and summer warming seemed to accelerate the decomposition in cool‐temperate semi‐natural grassland.

    DOI

  • Lateral export of dissolved inorganic and organic carbon from a small mangrove estuary with tidal fluctuation

    T. Ohtsuka, T. Onishi, S. Yoshitake, M. Tomotsune, M. Kida, Y. Iimura, M. Kondo, V. Suchewaboripont, R. Cao, K. Kinjo, N. Fujitake

    Forests   11 ( 10 ) 1041 - 1041  2020.09  [Refereed]

     View Summary

    The significance of aquatic lateral carbon (C) export in mangrove ecosystems highlights the extensive contribution of aquatic pathways to the net ecosystem carbon budget. However, few studies have investigated lateral fluxes of dissolved organic carbon (DOC) and inorganic carbon (DIC), partly due to methodological difficulty. Therefore, we evaluated area-based lateral C fluxes in a small mangrove estuary that only had one exit for water exchange to the coast. We sampled water from the mouth of the creek and integrated discharge and consecutive concentration of mangrove-derived C (ΔC). Then, we estimated the area-normalized C fluxes based on the inundated mangrove area. DIC and DOC concentrations at the river mouth increased during ebb tide during both summer and winter. We quantified the ΔC in the estuary using a two-component conservative mixing model of freshwater and seawater. DIC and DOC proportions of ΔC concentrations at the river mouth during ebb tide was between 34% and 56% in the winter and 26% and 42% in the summer, respectively. DIC and DOC fluxes from the estuary were estimated to be 1.36 g C m−2 d−1 and 0.20 g C m−2 d−1 in the winter and 3.35 g C m−2 d−1 and 0.86 g C m−2 d−1 in the summer, respectively. Based on our method, daily fluxes are mangrove area-based DIC and DOC lateral exports that can be directly incorporated into the mangrove carbon budget.

    DOI

  • Effect of crab burrows on CO2 flux from the sediment surface to the atmosphere in a subtropical mangrove forest on Ishigaki island, southwestern Japan

    M. Tomotsune, H. Arai, S. Yoshitake, M. Kida, N. Fujitake, K. Kinjo, T. Ohtsuka

    Estuaries and Coasts   43 ( 1 ) 102 - 110  2020  [Refereed]

     View Summary

    © 2019, Coastal and Estuarine Research Federation. To clarify the effects of crab burrows on variation in sediment CO2 flux in mangrove forest, we measured the traits of crab burrows (density and entrance area size) and the CO2 flux rate from sediment surfaces, in areas with and without burrows, in a subtropical mangrove forest on Ishigaki Island, southwestern Japan. Burrow density and entrance area showed significant differences among seasons (warm, middle, and cool) and mangrove zones (upper-, middle-, and downstream), which may have depended on crab phenology, life cycle, and species composition. The sediment CO2 flux rate was significantly higher at plots with crab burrows (B+) than at those without burrows (B−) in each zone and season. However, standardized sediment CO2 flux rate by burrow surface area at B+ plots did not differ significantly from that at B− plots. In addition, there were no significant differences in sediment temperature and sediment water content between the two types of plots. Moreover, the level of microbial respiration differed significantly between sediments collected from the deep part and those collected from either the ground surface part or burrow walls. These results suggest that crab burrows increase sediment CO2 flux from the mangrove forest floor by increasing the sediment–atmosphere interface area, thereby inducing a change to aerobic conditions in the sediments around burrows. Therefore, the seasonal and spatial effect of crab burrows on the forest floor should be considered when evaluating sediment CO2 flux and examining the role of the mangrove ecosystem as a carbon sink.

    DOI

  • 大白川ブナ・ミズナラ成熟林(old-growth forest)における土壌窒素無機化速度の空間変動解析

    Shinpei Yoshitake

    日本土壌肥料学雑誌   (in press)  2019.12  [Refereed]

    DOI

  • Effect of biochar addition on leaf-litter decomposition at soil surface during three years in a warm-temperate secondary deciduous forest, Japan

    Y. Minamino, N. Fujitake, T. Suzuki, S. Yoshitake, H. Koizumi, M. Tomotsune

    Scientific Reports   9 ( 1 ) 16961 (2019)  2019.11  [Refereed]

     View Summary

    The addition of biochar to the forest floor should facilitate efficient carbon sequestration. However, little is known about how biochar addition effects litter decomposition, which is related to carbon and nutrient dynamics in forest ecosystems. This study evaluated the effect of biochar addition on leaf litter decomposition in a forest ecosystem. To examine whether leaf litter decomposition was stimulated above and below biochar, litterbag experiments were carried out for about 3 years in a field site where biochar was added at the rate of 0, 5 and 10 t ha−¹ (C0, C5 and C10 plots) to the forest floor in a temperate oak forest, Japan. Biochar addition at C10 significantly enhanced litter decomposition below biochar for 2 years after treatment and above biochar for 1 year after treatment. Litter water content in biochar plots tended to increase under dry conditions. Biochar addition enhanced litter decomposition because of increased microbial activity with increased moisture content and accelerated the decomposition progress rather than changing the decomposition pattern. However, the carbon emission through changing leaf litter decomposition was small when compared with the carbon addition by biochar, indicating that biochar could be an effective material for carbon sequestration in forest ecosystems.

    DOI PubMed

  • P2-1-3 タイ王国トラート川河口マングローブ林における植生・深度別土壌有機物の分光学的特徴(2-1 土壌有機・無機成分の構造・機能・ダイナミクス,2019年静岡大会)

    渡邉 育弥, 木田 森丸, 友常 満利, 近藤 美由紀, 吉竹 晋平, 飯村 康夫, 金城 和俊, 大塚 俊之, 藤嶽 暢英

    日本土壌肥料学会講演要旨集   65   19 - 19  2019.09

    DOI CiNii

  • Stemflow hydrology and DOM flux in relation to tree size and rainfall event characteristics

    S. Chen, R. Cao, S. Yoshitake, T. Ohtsuka

    Agricultural and Forest Meteorology   279   107753  2019.09  [Refereed]

     View Summary

    © 2019 Elsevier B.V. Numerous studies have examined the variability of stemflow across different tree species under different meteorological conditions. However, studies have rarely considered stemflow associated with individual rainfall events and stemflow DOM flux. Therefore, we collected stemflow data from >100 individual rainfall events across four diameter size classes (20–30 cm, 30–40 cm, 40–50 cm, and DBH > 50 cm) of Castanopsis cuspidata in an evergreen forest (35° 26′ N, 136° 47E). The main objectives were to evaluate the stemflow hydrology and DOM flux characteristics in relation to tree size and different rainfall intensities based on a large dataset of individual rainfall events. In line with previous studies, the mean stemflow volumes and percentages of larger trees were higher than those of smaller trees; smaller trees have a higher funneling ratio than larger trees at both tree-scale (FRt) and stand-scale (FRs), which means that smaller trees are more effective in funneling water to their base. However, tree size significantly affects the stemflow volume and percentage only when the rainfall intensity is below 15 mm h−1. Tree size had a limited effect on the stemflow DOM concentration and stemflow DOM yield at a monthly scale. However, stemflow DOM flux and the flux-based DOM enrichment ratio were affected profoundly by tree size. Similar to the funneling ratio, small trees had a higher flux-based DOM enrichment ratio and supplied more DOM per unit trunk basal area. Thus, in addition to tree species, we suggest that tree size is also an important factor influencing the heterogeneity of the spatial patterns of the soil solution chemistry near the tree trunks.

    DOI

  • Priming effect of Miscanthus sinensis derived biochar on brown forest soil

    Y. Iimura, M. Natsuhara, T. Ohtsuka, M. Tomotsune, S. Yoshitake, H. Koizumi

    Soil Science and Plant Nutrition   (in press) ( 6 ) 550 - 556  2019.09  [Refereed]

     View Summary

    © 2019, © 2019 Japanese Society of Soil Science and Plant Nutrition. The role of biochar in the mitigation of CO2 emissions has been extensively studied in agricultural soils but is not well understood in Japanese forest soils, especially in relation to CO2 emissions from applied biochar and native soil C (i.e., the priming effect; PE). We hypothesized that the type of biochar and/or the application method (mixed or sprinkled) affect the direction and magnitude of PE in forest soil, and in particular, negative PE can be achieved relatively easily if biochar produced under higher temperature conditions were sprinkled on the soil surface. To test our hypothesis, we measured CO2 emissions from biochar-amended brown forest soil in Japan and examined its PE by conducting a medium-term (~4 months) incubation study. As substrates, we used plain straw from the C4 grass Miscanthus sinensis (SU) and two qualities of biochar produced from it at either 300°C (BC300) or 800°C (BC800) and compared two application methods: mixed into or sprinkled onto the soil. BC800 had a greater C content and C:N ratio as well a lower volatile matter content and higher nonvolatile matter content than BC300. SU had the lowest C content and C:N ratio of all the substrates. We found that biochar quality (volatile and nonvolatile matter content) was clearly related to the decomposition rate when mixed into the soil, but we could not find this relationship when biochar was sprinkled onto the soil. The addition of biochar to the soil induced a positive PE in the early stages (except for BC800 sprinkled) but suppressed CO2 emissions from native soil organic matter (negative PE) in the later stages, whereas the PE with SU application was always positive regardless of application method. Our results suggest that when biochar is sprinkled onto soil it is more likely to suppress soil-derived CO2 emission than when mixed in soil; however, the trend based on biochar quality was unclear.

    DOI

  • Nitrogen deposition and responses of forest structure to nitrogen deposition in a cool-temperate deciduous forest

    R. Cao, S. Chen, S. Yoshitake, T. Ohtsuka

    Forests   10 ( 8 ) 631  2019.07  [Refereed]

     View Summary

    © 2019 by the authors. Few studies have reported the estimation of nitrogen (N) deposition, including dissolved organic N (DON) fluxes, through water flows and the contribution of snowfall in Asia. In this study, the concentrations and fluxes of DON and dissolved inorganic N (DIN) in bulk precipitation (BP), the throughfall (TF) of trees and understory dwarf bamboo, and stemflow (SF) were evaluated in a cool-temperate forest over three years to clarify N fluxes via precipitation and responses of trees and understory canopies to N deposition. The input of N to the study site in BP was 11.1 ± 1.71 kg N ha-1 year-1, with a significant contribution from DON (78%). Snowfall fluxes contributed up to 46% of the totalNinput, with variations related to the amount of snowfall (2.08-5.52 kgNha-1 year-1). The forest canopy enriched DON (2.11 ± 0.42 kg N ha-1 year-1) but consumed NO3 + NO2-N (-0.73 ± 0.19 kg N ha-1 year-1). In contrast, through the understory bamboo canopy, DON (-1.02 ± 0.55 kg N ha-1 year-1) decreased while DIN (0.35 ± 0.44 kg N ha-1 year-1) increased. This study indicates that DON and snowfall should not be neglected when evaluating total N deposition into forest ecosystems, especially in remote regions. The canopy processes related to the dissolved N in the presence of understory plants might have significant implications for the internal N cycle in forest ecosystems.

    DOI

  • Changes in dissolved organic matter composition and dynamics in a subtropical mangrove river driven by rainfall

    M. Kida, M. Tanabe, M. Tomotsune, S. Yoshitake, K. Kinjo, T. Ohtsuka, N. Fujitake

    Estuarine, Coastal and Shelf Science   223   6 - 17  2019.07  [Refereed]

     View Summary

    © 2019 Elsevier Ltd Dissolved organic matter (DOM) plays an important role in sustaining ecosystem services of mangrove forests through well-described biogeochemical and ecological functions. This study was conducted in the Fukido River (Ishigaki Island, Japan) to better understand the seasonal and episodic changes in DOM concentration and composition in a subtropical mangrove system. Water samples were collected seasonally along a headwater–mangrove–sea transect on 10 occasions from September 2014 through June 2016. DOM was fractionated based on hydrophobicity into two fractions (hydrophobic and hydrophilic) and also analyzed by excitation-emission matrix spectroscopy combined with parallel factor analysis (PARAFAC). Although seasonal changes in DOM concentration and composition were not observed, both hydrophobic and hydrophilic DOM concentrations and levels of the identified three PARAFAC components clearly increased during a typhoon event. It is suggested that episodic increases in freshwater input due to a typhoon caused enhanced leaching of DOM from mangrove litter and dissolution of mangrove soil organic matter (SOM), which was otherwise retained in the mangrove soil by salinity-induced aggregation. The aggregation–dissolution properties of SOM are crucial in determining the magnitude of DOM outwelling and possibly SOM accumulation rate by enhancing advective DOM exchanges. Future studies are needed to evaluate the size of the carbon pool and outwelling of DOM after classifying mangrove forests based on the hydrological regime that influences biogeochemical conditions in the forests. Regional Index Terms: Japan, Okinawa, Ishigaki, Fukido.

    DOI

  • Cultural ecosystem services provided by flowering of cherry trees under climate change: a case study of the relationship between the periods of flowering and festivals

    S. Nagai, T.M. Saitoh, S. Yoshitake

    International Journal of Biometeorology   63 ( 8 ) 1051 - 1058  2019.07  [Refereed]

     View Summary

    In Japan, cherry blossoms are an important tourism resource and provide many cultural ecosystem service benefits. Under future warming conditions, we will require adaptions such as changing the timing of flower festivals to account for changes in the flowering phenology. In this study, we evaluated the coincidence between the flowering phenology of cherry blossoms and the associated festival periods in two Japanese cities under past, recent, and future climate conditions. We examined the situation in Shinhidaka, where the flower festival period changes every year, and Takayama, where the festival period is fixed to coincide with a shrine's annual spring festival. Currently, the average dates of beginning of flowering (more than four or five flowers open in an index tree; BBCH60) and full bloom (equal to or more than 80% of flowers open in an index tree; after BBCH65) in Shinhidaka (day of year (DOY) 126 and 130) are later than the long national holiday of Golden Week (DOY 119 to 125). The respective dates in Takayama (DOY 106 and 111, respectively) are later than the local a festival period (DOY 104 and 105). Under a scenario of 1.0 to 2.0 degrees C warming, the full blooming dates in Shinhidaka will coincide with Golden Week, whereas under 1.0 to 1.5 degrees C warming, the full blooming dates in Takayama will coincide with the spring festival period. Thus, moderate warming may increase the value of cherry blossoms to the tourism industry. Under more than 3.5 degrees C warming in Shinhidaka and 2.5 degrees C warming in Takayama, however, cherry blossoms will have already dropped by Golden Week and the spring festival period, respectively, suggesting that greater warming may decrease the value of this tourism resource.

    DOI

  • Stand dynamics and aboveground net primary productivity of a mature subtropical mangrove forest on Ishigaki Island, south-western Japan.

    T. Ohtsuka, M. Tomotsune, V. Suchewaboripont, Y. Iimura, M. Kida, S. Yoshitake, M. Kondo, K. Kinjo

    Regional Studies in Marine Science   27  2019.03  [Refereed]

     View Summary

    © 2019 Elsevier B.V. There are insufficient data regarding forest productivity of mature mangroves near the northern limit of mangrove distribution in subtropical East Asia. We conducted the present study to determine the stand dynamics and net primary production (NPP) of a mature mangrove forest on Ishigaki Island in south-western Japan over three successive years, using a large permanent plot. The two mangrove species present were Bruguiera gymnorrhiza and Rhizophora stylosa. The aboveground biomass in the plot was high, despite the high latitude (24 ∘ 29 ′ N) of the site, gradually increasing from 158.4 Mg ha −1 to 164.6 Mg ha −1 over the three-year study period. This increase was attributable to an increase in the biomass of B. gymnorrhiza. The biomass of R. stylosa, however, decreased during the same period because of a threefold-higher mortality rate and a lower relative growth rate of this species compared with B. gymnorrhiza. The mangrove forest was in the late successional stage, following a pioneer R. stylosa forest that was widely distributed throughout the study plot as standing dead trees and logs. The aboveground NPP of the mangrove forest was 10.66 ± 1.46 Mg ha −1 y −1 , partitioned into 3.10 ± 0.51 Mg ha −1 y −1 as woody NPP (net increase in aboveground woody parts, SI), and 7.56 ± 0.99 Mg ha −1 y −1 as foliage NPP (litter production, including foliage and reproductive organs, L n ). The mature mangrove forest had a relatively low SI/L n ratio (0.41 ± 0.03), although litter fall production was within the range previously recorded for mangroves. The lower woody NPP in the mature mangroves was due to the exclusion of R. stylosa once the stand was in a late successional stage dominated by B. gymnorrhiza.

    DOI

  • Priming effect of Miscanthus sinensis derived biochar on brown forest soil

    Iimura Y, Natsuhara M, Ohtsuka T, Tomotsune M, Yoshitake S, Koizumi H

    Soil Science and Plant Nutrition   65 ( 6 ) 550 - 556  2019.01  [Refereed]

     View Summary

    © 2019, © 2019 Japanese Society of Soil Science and Plant Nutrition. The role of biochar in the mitigation of CO2 emissions has been extensively studied in agricultural soils but is not well understood in Japanese forest soils, especially in relation to CO2 emissions from applied biochar and native soil C (i.e., the priming effect; PE). We hypothesized that the type of biochar and/or the application method (mixed or sprinkled) affect the direction and magnitude of PE in forest soil, and in particular, negative PE can be achieved relatively easily if biochar produced under higher temperature conditions were sprinkled on the soil surface. To test our hypothesis, we measured CO2 emissions from biochar-amended brown forest soil in Japan and examined its PE by conducting a medium-term (~4 months) incubation study. As substrates, we used plain straw from the C4 grass Miscanthus sinensis (SU) and two qualities of biochar produced from it at either 300°C (BC300) or 800°C (BC800) and compared two application methods: mixed into or sprinkled onto the soil. BC800 had a greater C content and C:N ratio as well a lower volatile matter content and higher nonvolatile matter content than BC300

    DOI

  • Effect of crab burrows on CO2 efflux from the sediment surface to the atmosphere in a subtropical mangrove forest on Ishigaki Island, southwestern Japan

    M. Tomotsune, H. Arai, S. Yoshitake, M. Kida, N. Fujitake, K. Kinjo, T. Ohtsuka

    Estuaries and Coasts    2019  [Refereed]

    DOI

  • Contribution of humic substances to dissolved organic matter optical properties and iron mobilization

    Morimaru Kida, Nobuhide Fujitake, Vilanee Suchewaboripont, Sasitorn Poungparn, Mitsutoshi Tomotsune, Miyuki Kondo, Shinpei Yoshitake, Yasuo Iimura, Kazutoshi Kinjo, Chatree Maknual, Toshiyuki Ohtsuka

    Aquatic Sciences   80 ( 3 ) 26  2018.07  [Refereed]

     View Summary

    Humic substances (HS) are the primary constituents of dissolved organic matter (DOM) and play pivotal roles in aquatic systems. Optical indices of DOM, such as specific UV absorbance (SUVA254), the fluorescence index (FI) and biological index (BIX), have gained wide interest because of their ease of use. In this study, we explored the relationship between HS and the indices in the Trat River Basin (eastern Thailand) from headwaters to the river mouth through the distinct dry and rainy seasons to examine whether changes in index values reflect variability in the relative contribution of HS to DOM, or %HS. The results show that %HS and the indices did not exhibit significant linear relationships (FI and BIX, P &gt
    0.05), or the relationships changed seasonally (SUVA254). However, analyzing the indices versus %HS did show clear DOM composition changes by season with more humic-like or terrestrial material in the rainy season. Relationships between DOM and dissolved iron (dFe) concentrations were also explored. Separating the relationships of DOM versus dFe into HS versus dFe and non-HS versus dFe provides us the opportunity to better understand which fraction contributes more to dFe mobilization. The results indicate stronger positive linear relationships between HS and dFe concentrations independent of river tributary. Overall, this study highlights the importance of quantifying HS for the study of DOM dynamics or compositional changes along a river transect as well as for DOM-induced iron mobilization.

    DOI

  • Effects of soil temperature and tidal condition on variation in carbon dioxide flux from soil sediment in a subtropical mangrove forest

    M. Tomotsune, S. Yoshitake, Y. Iimura, M. Kida, N. Fujitake, H. Koizumi, T. Ohtsuka

    Journal of Tropical Ecology   34 ( 4 ) 268 - 275  2018.07  [Refereed]

     View Summary

    © 2018 Cambridge University Press. The variation in CO2 flux from the forest floor is important in understanding the role of mangrove forests as a carbon sink. To clarify the effects of soil temperature and tidal conditions on variation in CO2 flux, sediment-atmosphere CO2 fluxes were measured between June 2012 and May 2013. We used the closed chamber method for two plots, with a 0.5 m difference in elevation (B, high elevation; R-B, low elevation), in a mangrove forest in south-western Japan. CO2 fluxes were highest in the warm season and showed a weak positive correlation with soil temperature in both forests. Estimated monthly CO2 flux showed moderate seasonal variation in accordance with the exposure duration of the soil surface under tidal fluctuation. Additionally, measured CO2 flux and soil temperature were slightly higher in the R-B plot than the B plot, although estimated annual CO2 flux was higher in the B plot than the R-B plot due to different exposure durations. These results suggest that variation in the exposure duration of the forest floor, which changes seasonally and microgeographically, is important in evaluating the annual CO2 flux at a local scale and understanding the role of mangrove ecosystems as regulators of atmospheric CO2.

    DOI

  • 8 million phenological and sky images from 29 ecosystems from the Arctic to the tropics: the Phenological Eyes Network

    Shin Nagai, Tomoko Akitsu, Taku M. Saitoh, Robert C. Busey, Karibu Fukuzawa, Yoshiaki Honda, Tomoaki Ichie, Reiko Ide, Hiroki Ikawa, Akira Iwasaki, Koki Iwao, Koji Kajiwara, Sinkyu Kang, Yongwon Kim, Kho Lip Khoon, Alexander V. Kononov, Yoshiko Kosugi, Takahisa Maeda, Wataru Mamiya, Masayuki Matsuoka, Trofim C. Maximov, Annette Menzel, Tomoaki Miura, Toshie Mizunuma, Tomoki Morozumi, Takeshi Motohka, Hiroyuki Muraoka, Hirohiko Nagano, Taro Nakai, Tatsuro Nakaji, Hiroyuki Oguma, Takeshi Ohta, Keisuke Ono, Runi Anak Sylvester Pungga, Roman E. Petrov, Rei Sakai, Christian Schunk, Seikoh Sekikawa, Ruslan Shakhmatov, Yowhan Son, Atsuko Sugimoto, Rikie Suzuki, Kentaro Takagi, Satoru Takanashi, Shunsuke Tei, Satoshi Tsuchida, Hirokazu Yamamoto, Eri Yamasaki, Megumi Yamashita, Tae Kyung Yoon, Toshiya Yoshida, Mitsunori Yoshimura, Shinpei Yoshitake, Matthew Wilkinson, Lisa Wingate, Kenlo Nishida Nasahara

    Ecological Research   33 ( 6 ) 1 - 2  2018.06  [Refereed]

     View Summary

    We report long-term continuous phenological and sky images taken by time-lapse cameras through the Phenological Eyes Network (http://www.pheno-eye.org. Accessed 29 May 2018) in various ecosystems from the Arctic to the tropics. Phenological images are useful in recording the year-to-year variability in the timing of flowering, leaf-flush, leaf-coloring, and leaf-fall and detecting the characteristics of phenological patterns and timing sensitivity among species and ecosystems. They can also help interpret variations in carbon, water, and heat cycling in terrestrial ecosystems, and be used to obtain ground-truth data for the validation of satellite-observed products. Sky images are useful in continuously recording atmospheric conditions and obtaining ground-truth data for the validation of cloud contamination and atmospheric noise present in satellite remote-sensing data. We have taken sky, forest canopy, forest floor, and shoot images of a range of tree species and landscapes, using time-lapse cameras installed on forest floors, towers, and rooftops. In total, 84 time-lapse cameras at 29 sites have taken 8 million images since 1999. Our images provide (1) long-term, continuous detailed records of plant phenology that are more quantitative than in situ visual phenological observations of index trees
    (2) basic information to explain the responsiveness, vulnerability, and resilience of ecosystem canopies and their functions and services to changes in climate
    and (3) ground-truthing for the validation of satellite remote-sensing observations.

    DOI

  • Soil microbial succession along a chronosequence on a High Arctic glacier foreland, Ny-Ålesund, Svalbard: 10 years’ change

    Shinpei Yoshitake, Masaki Uchida, Yasuo Iimura, Toshiyuki Ohtsuka, Takayuki Nakatsubo

    Polar Science   16   59 - 67  2018.06  [Refereed]

     View Summary

    Rapid glacial retreat in the High Arctic causes the expansion of new habitats, but the successional trajectories of soil microbial communities are not fully understood. We examined microbial succession along a chronosequence twice with a 10-year interval in a High Arctic glacier foreland. Soil samples were collected from five study sites with different ages and phospholipid fatty acids analysis was conducted to investigate the microbial biomass and community structure. Microbial biomass did not differ significantly between the two sampling times but tended to increase with the chronosequence and showed a significant correlation with soil carbon (C) and nitrogen (N) content. Microbial community structure clearly differed along the chronosequence and was correlated with C and N content. The largest shift in community structure over 10 years was observed in the newly exposed sites after deglaciation. The accumulation of soil organic matter was regarded as an important determinant both of microbial biomass and community structure over the successional period. In contrast, the initial microbial community on the newly exposed soil changed rapidly even in the High Arctic, suggesting that some key soil processes such as C and N cycling can also shift within the relatively short period after rapid glacial retreat.

    DOI

  • Investigation of the potential of drone observations for detection of forest disturbance caused by heavy snow damage in a Japanese cedar (Cryptomeria japonica) forest

    S. Nagai, T.M. Saitoh, K. Kajiwara, S. Yoshitake, Y. Honda

    Journal of Agricultural Meteorology   74 ( 3 ) 123 - 127  2018.05  [Refereed]

     View Summary

    Forest disturbance by heavy snow seriously affects ecosystem functions and provision of ecosystem services. To evaluate the spatial distribution of this disturbance over large areas, it is necessary to develop a flexible, inexpensive, and generalizable method based on remote sensing. Here, we examined the ability of an unmanned drone to detect the disturbance caused by heavy snow in a Japanese cedar (Cryptomeria japonica) forest, which is a typical landscape species in Japan's mountainous areas. We obtained aerial photographs in late October 2016 using the drone in a research plot where many individuals were damaged by moist, heavy snow in mid-December 2014. The forest disturbance rate was estimated by visually inspecting the structure from motion (SfM) point clouds generated from the drone's aerial photographs. We detected 90 to 96% of healthy individuals, but many tilted trees and trees with broken stems but an intact canopy were misidentified as healthy individuals. The estimated forest disturbance rate (33%) obtained from the SfM point clouds coincided well with the actual forest disturbance rate (35%) obtained from tree surveys. Consequently, this approach can potentially be used to detect narrow and patchy disturbances in Japanese cedar forest, although further observations at multiple points will be required to develop the accuracy of this approach.

    DOI

  • Non-destructive measurement of soil respiration in a grassland ecosystem using the multiple-microchambers method

    Nobuhiko Suminokura, Mayuko Suzuki, Kenta Tanami, Mitsutoshi Tomotsune, Shinpei Yoshitake, Hiroshi Koizumi

    Ecological Research   33 ( 2 ) 471 - 477  2018.03  [Refereed]

     View Summary

    The chamber method with plant clipping has been widely used for measuring soil respiration (SR) in grassland ecosystems. However, plant clipping may cause overestimation of SR by changing the environmental factors and injuring the plants. To solve these problems, we developed a new non-destructive method using multiple-microchambers (3 cm diameter, 8 cm height), which enables measurement of SR without plant clipping by installing chambers into gaps among the grasses. The new method was compared with the conventional method at various flow rates in vitro to assess the accuracy of SR measurement. The new method overestimated the SR rate
    however, the ratio of overestimation to the conventional method was constant for each flow rate. These ratios fitted the logarithmic curve, indicating the potential for correction of the SR rate measured by the new method using the logarithmic equation. The corrected SR rate obtained by the new method was equal to the rate by the conventional method. This suggests that accurate measurement of SR in grassland ecosystems is possible using the multiple-microchambers method. We then compared the non-destructive method and the destructive method in situ on summer season and found that the destructive method overestimated SR rate in the grassland ecosystem by about 276% on average. There were two possible reasons for this overestimation
    first, the clipping treatment may change environmental conditions such as soil temperature and soil water content, and second, it may directly increase plant respiration.

    DOI

  • Soil Net Nitrogen Mineralization at Different Ecosystem Development Stages after the Year 2000 Eruption on Miyakejima Island

    Shinpei Yoshitake

    Journal of Ecosystem & Ecography   8 ( 1 ) 250  2018.02  [Refereed]

    DOI

  • Stand Dynamics and Biomass Increment in a Lucidophyllous Forest over a 28-Year Period in Central Japan

    Siyu Chen, Akira Komiyama, Shogo Kato, Ruoming Cao, Shinpei Yoshitake, Toshiyuki Ohtsuka

    FORESTS   8 ( 10 ) 397  2017.10  [Refereed]

     View Summary

    Secondary lucidophyllous forest is one of the dominant forests in human-dominated subtropical/warm-temperate regions in East Asia. There were few direct monitoring techniques to elucidate the following hypotheses: (a) self-thinning may govern the stand development process and (b) wood production decline can be observed during secondary succession in a lucidophyllous forest. We conducted a long-term study at a permanent plot in central Japan, since 1989. The forest consists mainly of Castanopsis cuspidata in a canopy layer, Cleyera japonica, and Eurya japonica in a subtree layer. During the 28-year period, the basal area of the stand significantly increased due to the growth of C. cuspidata, from 29.18 +/- 1.84 (87.8% of total) to 38.71 +/- 2.22 m(2) ha(-1) (91.9%), while the stem density of C. cuspidata significantly decreased from 666 +/- 13 to 404 +/- 10 stems ha(-1) in proportion to accumulating biomass (117.8 to 166.6 ton ha(-1)). The annual woody net primary production ranged from 2.40 +/- 0.13 to 3.93 +/- 0.33 ton ha(-1) year(-1) as a nearly 70-year-old forest. There was no age-related decline of woody net primary production (NPP) was found during secondary succession, and the growth of individual tree still increased when the self-thinning process governed the stand.

    DOI

  • Dissolved organic carbon (DOC) input to the soil: DOC fluxes and their partitions during the growing season in a cool-temperate broad-leaved deciduous forest, central Japan

    Siyu Chen, Shinpei Yoshitake, Yasuo Iimura, Chiyuki Asai, Toshiyuki Ohtsuka

    ECOLOGICAL RESEARCH   32 ( 5 ) 713 - 724  2017.09  [Refereed]

     View Summary

    Dissolved organic carbon (DOC) plays an important role in C cycling in forest ecosystems. Here we measured the concentrations and fluxes of DOC in a cool-temperate broad-leaved deciduous forest (Takayama Forest) to quantify the contribution of DOC from different forest water flux conditions. Mean DOC concentration during the growing season increased in the sequence from bulk precipitation (2.98 +/- 0.45 mg L-1), throughfall above dwarf bamboo (6.84 +/- 0.45 mg L-1), throughfall below dwarf bamboo (7.08 +/- 0.42 mg L-1), stemflow (15.05 +/- 0.98 mg L-1), and litter leachate (21.33 +/- 1.01 mg L-1). Litter leachate DOC concentration, being high in spring and autumn, which was fairly correlated with the amount of litterfall of bamboo and trees. In stemflow, the DOC concentration was high during early summer and gradually decreased, in addition, it also showed dramatic variation among different plant species. Litter leachate (72.5%) accounted for most of the DOC input to the soil during the growing season (311.5 kg C ha(-1) 7 months(-1)), while stemflow (1.6%) contributed the least. A great quantity of precipitation at the study site was associated with a subsequent high atmospheric contribution of DOC flux (8.6%), which was more than half of throughfall (16.5%). The high input of DOC to the soil and andisol soil characteristics at the Takayama Forest suggest that the DOC fluxes are vital to the soil carbon sequestration. Therefore, DOC fluxes should be taken into account when the carbon balance is assessed at forest ecosystems.

    DOI

  • Measurements of carbon efflux from exposed and submerged sediment surfaces using the automatic open/close chamber method in a mangrove forest ― A challenge to clarify carbon dynamics in the pedosphere ―

    M. Tomotsune, Y. Suzuki, T. Ohtsuka, S. Yoshitake, N. Suminokura, H. Shinkai, H. Koizumi

    Japanese Journal of Ecology   67 ( 2 ) 75 - 83  2017.08  [Refereed]

    DOI

  • Seasonality of leaf litter and leaf area index data for various tree species in a cool-temperate deciduous broad-leaved forest, Japan, 2005-2014

    Shin Nagai, Kenlo Nishida Nasahara, Shinpei Yoshitake, Taku M. Saitoh

    ECOLOGICAL RESEARCH   32 ( 3 ) 297 - 297  2017.05  [Refereed]

     View Summary

    This paper reports seasonal data regarding leaf litter for 14 deciduous broad-leaved species and one evergreen coniferous species as well as leaf area index (LAI) data for the 14 deciduous broad-leaved species in a cool-temperate deciduous broad-leaved forest in Japan. The seasonal leaf biomass of various tree species is important for accurately evaluating ecosystem functions such as photosynthesis and evapotranspiration under climate change. However, there is a lack of freely available, long-term data. We collected litterfall every 1 to 4 weeks from September or October to November or December each year from 2005 to 2014 in Takayama, Japan (36A degrees 08'46aEuro(3)N, 137A degrees 25'23aEuro(3)E, 1420 m a.s.l.). After sorting the litter into leaves (according to species categories), stems + branches, and "other", we dried and weighed the litter groups. We also collected seasonal leaf data (number of leaves and leaf length and width) for each broad-leaved species, which we recorded every 1 to 4 weeks from April or May to October or November using multiple target shoots. To estimate the LAI in autumn for each deciduous broad-leaved species, we used a semi-empirical model of the vertical integration of leaf dry mass per unit leaf area. To estimate the LAI in spring and summer, we used the relationship between the LAI in autumn and the seasonal leaf data. Our data provide input, calibration, and validation parameters for determining LAI based on satellite remote-sensing observations or radiative transfer models and for use in ecosystem models.

    DOI

  • Spatial Upscaling of Soil Respiration under a Complex Canopy Structure in an Old-Growth Deciduous Forest, Central Japan

    Vilanee Suchewaboripont, Masaki Ando, Shinpei Yoshitake, Yasuo Iimura, Mitsuru Hirota, Toshiyuki Ohtsuka

    FORESTS   8 ( 2 ) 36  2017.02  [Refereed]

     View Summary

    The structural complexity, especially canopy and gap structure, of old-growth forests affects the spatial variation of soil respiration (Rs). Without considering this variation, the upscaling of Rs from field measurements to the forest site will be biased. The present study examined responses of Rs to soil temperature (Ts) and water content (W) in canopy and gap areas, developed the best fit model of Rs and used the unique spatial patterns of Rs and crown closure to upscale chamber measurements to the site scale in an old-growth beech-oak forest. Rs increased with an increase in Ts in both gap and canopy areas, but the effect of W on Rs was different between the two areas. The generalized linear model (GLM) analysis identified that an empirical model of Rs with the coupling of Ts and W was better than an exponential model of Rs with only Ts. Moreover, because of different responses of Rs to W between canopy and gap areas, it was necessary to estimate Rs in these areas separately. Consequently, combining the spatial patterns of Rs and the crown closure could allow upscaling of Rs from chamber-based measurements to the whole site in the present study.

    DOI

  • Measurements of carbon efflux from exposed and submerged sediment surfaces using the automatic open/close chamber method in a mangrove forest ― A challenge to clarify carbon dynamics in the pedosphere

    Mitsutoshi Tomotsune, Yohei Suzuki, Toshiyuki Ohtsuka, Shinpei Yoshitake, Nobuhiko Suminokura, Hisashi Shinkai, Hiroshi Koizumi

    Japanese Journal of Ecology   67 ( 2 ) 75 - 83  2017  [Refereed]

     View Summary

    We measured the CO2 flux from sediment surfaces (soil respiration in the pedosphere to the atmosphere) in a mangrove forest using an improved automatic open/close chamber (AOCC) method. Soil respiration rates and environmental factors were continuously measured from 4 to 8 July, 2013, in a mangrove dominated by Bruguiera gymnorrhiza. Variation in respiration rate did not exhibit a clear correlation with soil temperature. However, tidal effects were related to variation in soil temperature and may also have contributed to variation in respiration rate. High respiration rates were detected immediately before submergence or after exposure, due to the physical effects of tidal variation. Respiration rates during the period of exposure were lower than those in terrestrial ecosystems, likely due to three factors unique to mangrove forests: soil respiration measurements generally do not include root respiration, organic matter decomposition is restricted to a shallow anaerobic area, and some mineralized carbon is lost as dissolved inorganic carbon. Respiration rates during submergence were half of those measured during exposed conditions, suggesting that previous studies overestimated annual soil respiration. Therefore, measuring soil respiration rates during both exposed and submerged conditions using the AOCC method provides a much more accurate understanding of carbon dynamics in the pedosphere of mangrove forests.

    DOI

  • Effects of long-term experimental warming on plants and soil microbes in a cool temperate semi-natural grassland in Japan

    Mayuko Suzuki, Nobuhiko Suminokura, Kenta Tanami, Shinpei Yoshitake, Shingo Masuda, Mitsutoshi Tomotsune, Hiroshi Koizumi

    ECOLOGICAL RESEARCH   31 ( 6 ) 957 - 962  2016.11  [Refereed]

     View Summary

    To clarify the effects of long-term warming on ecosystem matter cycling, we conducted an in situ 7-year experimental warming (2009-2015) using infrared heaters in a cool temperate semi-natural grassland in Japan. We measured plant aboveground biomass, soil total C and N, soil inorganic N (NH4 (+)-N and NO3 (-)-N), and soil microbial biomass for 7 years (2009-2015). We also measured heterotrophic respiration for 2 years (2013-2014) and assessed net N mineralization and nitrification in 2015. We found that warming immediately increased plant aboveground biomass, but this effect ceased in 2013. However, the soil microbial biomass was continuously depressed by warming. Soil inorganic N concentrations in warmed plots substantially increased in the later years of the experiment (2013-2015) and the potential net N mineralization rate was also higher than in the earlier years. In contrast, heterotrophic respiration decreased with warming in 2013-2014. Our observations indicate that long-term warming has a contrasting effect on plants and soil microbes. In addition, the warming could have different effects on subterranean C and N cycling. To enhance the accuracy of estimation of future climate change, it is essential to continuously observe the warming effects on ecosystems and to focus on the change in subterranean C and N cycling.

    DOI

  • Substrate limitation to soil microbial communities in a subalpine volcanic desert on Mount Fuji, Japan

    S. Yoshitake, M. Fujiyoshi, T. Masuzawa, H. Koizumi

    EUROPEAN JOURNAL OF SOIL BIOLOGY   73   34 - 45  2016.03  [Refereed]

     View Summary

    We examined two hypotheses based on laboratory amendment experiments: (1) that development of the soil microbial community on volcanic deserts was regulated by substrate limitation; and (2) that the type and the extent of substrate limitation would change along the succession gradient. Soils were collected from the early (Stage B) and the late (Stage F) stages of primary succession of a subalpine volcanic desert on Mt. Fuji and they were amended with three carbon (C) sources (glucose, cellulose, or lignin), inorganic nitrogen (N), or phosphorus (P) sources alone or in a mixture. Respiration rates were monitored for 25 days and changes in microbial biomass and community structure were examined using the content and composition of phospholipid fatty acids. For both soils, the magnitude of the microbial response differed depending on the type of C source and it decreased in the following order reflecting the availability to microorganisms: glucose > cellulose > lignin. For Stage B soil, although any single amendment did not affect the microbial properties, combined amendment of C (glucose) and N increased microbial respiration and biomass and shifted the microbial community structure. In contrast, microbial properties in Stage F soils responded positively to single amendments of C source. Our results suggest that the microbial community in the early stage of succession is primarily limited by simultaneous shortage of C and N sources but the quality of the C source becomes more important in the late successional stages, which have large, but recalcitrant, organic matter pools in the soil. (C) 2016 Elsevier Masson SAS. All rights reserved.

    DOI

  • Uncertainties involved in leaf fall phenology detected by digital camera

    Shin Nagai, Tomoharu Inoue, Toshiyuki Ohtsuka, Shinpei Yoshitake, Kenlo Nishida Nasahara, Taku M. Saitoh

    ECOLOGICAL INFORMATICS   30   124 - 132  2015.11  [Refereed]

     View Summary

    We evaluated the uncertainty in the estimation of year-to-year variability in the timing of leaf fall detected by the analysis of red, green and blue (RGB) values extracted from daily phenological images in a deciduous broad-leaved forest in Japan. We examined (1) the spatial distribution of individual tree species within a 1-ha permanent plot and the spatio-temporal variability of leaf litter of various species for 8 years; and (2) the relationship between the year-to-year variability of leaf fall detected by leaf litter and that detected by phenological images of various species. Uncertainties were caused by (1) the heterogeneous distribution of each species within the whole forest community; (2) the year-to-year variability of the timing of leaf fall among species; and (3) differences in leaf colouring and leaf fall patterns among species. Our results indicate the importance of integrating RGB analysis of each species and of the whole canopy on the basis of spatial locations of individuals and proportions of tree species within a forest to reduce uncertainty. (C) 2015 Elsevier B.V. All rights reserved.

    DOI

  • The effect of canopy structure on soil respiration in an old-growth beech-oak forest in central Japan

    Vilanee Suchewaboripont, Masaki Ando, Yasuo Iimura, Shinpei Yoshitake, Toshiyuki Ohtsuka

    ECOLOGICAL RESEARCH   30 ( 5 ) 867 - 877  2015.09  [Refereed]

     View Summary

    Soil respiration (R (s) ) is a key component in the estimation of the net ecosystem production (NEP) of old-growth forests, which are generally thought to have ceased carbon accumulation. The objectives of the present study were to characterize the spatial and temporal patterns of R (s) , and to identify the determinants of the spatial and temporal variability of R (s,) using general linear mixed models (GLMM), in an old-growth beech-oak forest. GLMM analyses identified monthly effect as a significant explanatory variable for temporal variation, as well as gap/canopy and soil water content (SWC) as explanatory variables for spatial variation, in R (s) . The complexity of vertical structure in the forest was reflected in the spatial pattern of R (s) , which was higher in canopy areas than in gap areas during the growing season, except in November. This spatial pattern was not affected by soil temperature. Moreover, SWC did not differ between gap and canopy areas, although SWC partially explained the spatial heterogeneity in R (s) . The carbon:nitrogen ratios of soil organic matter in canopy areas were significantly higher than those in gap areas. Fine root biomass was 1.7-fold greater in canopy areas than in gap areas, likely because of the higher R (s) in canopy areas, and root respiration made a much large contribution to R (s) than heterotrophic respiration. The different patterns of fine root biomass between gap and canopy areas mainly control the spatial heterogeneity in R (s) ; thus, it is worth considering the gap/canopy variability in R (s) when evaluating annual efflux in old-growth forests.

    DOI

  • Carbon accumulation rate of peatland in the High Arctic, Svalbard: Implications for carbon sequestration

    Takayuki Nakatsubo, Masaki Uchida, Akiko Sasaki, Miyuki Kondo, Shinpei Yoshitake, Hiroshi Kanda

    POLAR SCIENCE   9 ( 2 ) 267 - 275  2015.06  [Refereed]

     View Summary

    Moss tundra that accumulates a thick peat layer is one of the most important ecosystems in the High Arctic, Svalbard. The importance of this ecosystem for carbon sequestration was estimated from the apparent rates of carbon accumulation based on the C-14 age and amount of peat in the active layer. The study site at Stuphallet, Brogger Peninsula, northwestern Svalbard was covered with a thick peat layer dominated by moss species such as Calliergon richardsonii, Paludella squarrosa, Tomenthypnum nitens, and Warnstorfia exannulata. The average thickness of the active layer (brown moss and peat) was approximately 28 cm in 1 August 2011. The calibrated (cal) age of peat from the bottom of the active layer (20-30 cm below the peatland surface) ranged from 81 to 701 cal yr BP (median value of 2s range). Based on the total carbon (4.5-9.2 kg C m(-2)), the apparent rate of carbon accumulation in the active layer was 9.0-19.2 (g C m(-2) yr(-1)), which is similar to or greater than the net ecosystem production or net primary production reported for other vegetation types in this area. Our data suggest that moss tundra plays an important role in carbon sequestration in this area. (C) 2015 Elsevier B.V. and NIPR. All rights reserved.

    DOI

  • Change in biomass of an old-growth beech-oak forest of Mt. Hakusan over a 17-year period

    V. Suchewaboripont, Y. Iimura, S. Yoshitake, S. Kato, A. Komiyama, T. Ohtsuka

    Japanese Journal of Forest Environment   57 ( 1 ) 33 - 42  2015.06  [Refereed]

     View Summary

    To assess the community structural change and to document temporal trends in biomass accumulation of an old-growth forest over a period of 17 years, we surveyed the forest structure and tree diameter in a 1-ha plot established in a cool-temperate deciduous forest on the eastern slope of Mt. Hakusan in 1995 and 2012. In a stand dominated by Fagus crenata (beech) and Quercus mongolica var. crispula (oak), the largest diameter at breast height (DBH) in 2012 was 100.3 and 194.7 cm, respectively. Although the tree density (DBH &ge; 5 cm) increased from 908 to 940 stems ha^<-1> from 1995 to 2012, nine large dead trees were found in this period. Because of dead canopy trees, the gap enlarged and a change in the forest structure occurred in the tree and subtree layers according to mean tree weight-weight of individual trees (M-w) diagrams. The forest biomass was estimated to be 537.8 and 536.7 t ha^<-1> for 1995 and 2012, respectively. The biomass in this forest was extremely high compared with those in old-growth beech forests studied elsewhere in Japan because of the existence of some huge oak trees. The loss of biomass (73.7 t ha^<-1>), partly because of large dead oak trees, was compensated by the growth of beech. Thus, the change in biomass in the 17-year period was very small. The results of the present study indicated that this old-growth beech-oak forest showed nonequilibrium in forest community dynamics; however, the forest biomass was at a steady state.

    DOI CiNii

  • Soil microbial response to experimental warming in cool temperate semi-natural grassland in Japan

    Shinpei Yoshitake, Nozomi Tabei, Yu Mizuno, Hitomi Yoshida, Yuya Sekine, Makoto Tatsumura, Hiroshi Koizumi

    ECOLOGICAL RESEARCH   30 ( 2 ) 235 - 245  2015.03  [Refereed]

     View Summary

    To assess soil microbial response to global warming in cool temperate semi-natural grassland, we conducted an in situ warming experiment in grassland located in the mountains of central Japan. Five pairs of plots (control and warmed) of Zoysia japonica were established. For each pair of plots, one was warmed by ca. 2 A degrees C using infrared heaters during the growing seasons of 2009-2011. Above-ground biomass of Z. japonica was estimated using the modified point-frame method. Soil organic matter contents, soil total carbon and nitrogen contents, as well as inorganic nitrogen (ammonium and nitrate) contents were determined from soil samples. Total phospholipid fatty acid (PLFA) contents and PLFA compositions were determined and used as indices for total microbial biomass and community structure, respectively. Analyses showed that the warming increased the above-ground biomass of Z. japonica significantly. Soil organic matter and soil total nitrogen contents were significantly decreased, while soil ammonium content was significantly increased in the warmed plots. Soil microbial biomass (especially fungal biomass) was lower in the warmed plots, probably reflecting higher temperature, lower soil water content, and/or depletion in available nutrients. The significant decrease in fungal biomass, in combination with our PLFA composition data, suggests that the soil microbial community structure shifted from a fungal-dominated to a bacteria-dominated one, causing changes in community-level physiological activity.

    DOI

  • Preliminary observations of soil organic layers using a compact MRI for non-destructive analysis of internal soil structure

    Mitsutoshi Tomotsune, Shinpei Yoshitake, Rina Masuda, Hiroshi Koizumi

    ECOLOGICAL RESEARCH   30 ( 2 ) 303 - 310  2015.03  [Refereed]

     View Summary

    Soil organic layer samples of two different forest types were observed using compact MRI to visualize internal structure and clarify physical properties of forest soil. Soil pores and organic materials were distinguished by differences in proton mobility and visualized with a spatial resolution of 234 A mu m. Soil pore ratios and water mobility were calculated by image processing, and their differences between the two forest soils were detected. Our results suggest that compact MRI has potential for non-destructive analysis of soil physical properties and is expected to have significant applications in ecological studies.

    DOI

  • Year-to-year blooming phenology observation using time-lapse digital camera images

    Shin Nagai, Shinpei Yoshitake, Tomoharu Inoue, Rikie Suzuki, Hiroyuki Muraoka, Kenlo Nishida Nasahara, Taku M. Saitoh

    JOURNAL OF AGRICULTURAL METEOROLOGY   70 ( 3 ) 163 - 170  2014.09  [Refereed]

     View Summary

    Long-term continuous phenological observation of cherry tree blooming is an important and challenging task in the evaluation of year-to-year weather and climate changes in spring in Japan. Here, (1) we performed daily field observations with a time-lapse digital camera in a deciduous broad-leaved forest in Japan from January 2004 to December 2013; and (2) we detected year-to-year variations in the blooming phenology of Prunus sargentii by visual inspection of the images and by image analysis. We found that (1) the red digital numbers (i.e., the digital intensity values of the red pixels; DNR) extracted from the time-lapse digital camera images tended to peak in full bloom; and (2) the green excess index (GET) (based on the red, green, and blue digital numbers) tended to be lowest in full bloom. These results indicate that DNR and GEI are useful for detecting the timing of full bloom in P. sargentii.

    DOI

  • Deposition and decomposition of cattle dung and its impact on soil properties and plant growth in a cool-temperate pasture

    Shinpei Yoshitake, Hiromi Soutome, Hiroshi Koizumi

    ECOLOGICAL RESEARCH   29 ( 4 ) 673 - 684  2014.07  [Refereed]

     View Summary

    Livestock dung provides an important direct pathway by which carbon and nutrients enter soils in pasture ecosystems and affects carbon and nitrogen cycling indirectly through changes in soil and plant properties. Here, we quantify dung deposition, decomposition, and the effects of dung on soil and plants in a Zoysia japonica grassland in Japan. We determined (1) the distribution of dung, (2) the mass loss rate of dung and the amount of carbon respired as CO2, and (3) changes in soil properties and aboveground biomass of Z. japonica. Dung deposition was 4.0-9.7 g C and 0.4-1.0 g N m(-2) year(-1) and distributed patchily (Morishita's I (delta) &gt; 1). Most (71 %) of the carbon in dung deposited in June was lost within a single grazing period by aerobic decomposition, more than mass loss rate of Z. japonica litter in the first year (about 50 %), suggesting that grazing and defecation can accelerate carbon cycling compared with the typical litterfall-decomposition regime. Nitrogen in dung mass entered the soil as ammonium nitrogen and was nitrified. The spatiotemporal distribution of these processes corresponded to that of stimulated Z. japonica growth. These results suggested that dung deposition significantly affected the inorganic nitrogen status of soil and, therefore, the growth of Z. japonica. However, these effects were very restricted temporally (July-August) and spatially (within 10 cm from dung edge). Thus, such spatiotemporally restricted effects combined with the patchy distribution of dung may contribute to the heterogeneous structure of pasture ecosystems.

    DOI

  • Effects of the burrowing mud shrimp, Upogebia yokoyai, on carbon flow and microbial activity on a tidal flat

    Akiko Sasaki, Hiroki Nakao, Shinpei Yoshitake, Takayuki Nakatsubo

    ECOLOGICAL RESEARCH   29 ( 3 ) 493 - 499  2014.05  [Refereed]

     View Summary

    Mud shrimps, Upogebia spp., are major constituents of macrobenthic communities in tidal flats in Japan. The impact of Upogebia yokoyai on carbon flow on tidal flats was examined by comparing CO2 emission rates from plots with and without burrows in the Kurose River estuary, Japan. In situ CO2 emission rates from plots with burrows were significantly higher than from those without. Laboratory measurements using sediment core samples that excluded respiration of macrobenthic organisms showed similar trends. Although there were no significant differences in grain size distribution, water content, or ignition loss between the sediment cores with and without burrows, oxidation-reduction potential was significantly higher in sediment cores with burrows. Analysis of phospholipid fatty acids (PLFA) indicated that microbial biomass and community structure did not differ significantly between cores with and without burrows. However, microbial respiration activity, as indicated by CO2 emission rates per total PLFA content, was significantly higher in sediment cores with burrows than in those without. Our results indicate that burrows of U. yokoyai change the physicochemical conditions and increase microbial activity in the sediment, significantly affecting carbon flow in the tidal flat.

    DOI

  • Separation of root and heterotrophic respiration within soil respiration by trenching, root biomass regression, and root excising methods in a cool-temperate deciduous forest in Japan

    Mitsutoshi Tomotsune, Shinpei Yoshitake, Shinya Watanabe, Hiroshi Koizumi

    ECOLOGICAL RESEARCH   28 ( 2 ) 259 - 269  2013.03  [Refereed]

     View Summary

    Trenching (Tr), root biomass regression (RR), and root excising (RE) methods were used to estimate the contribution of root (RR) and heterotrophic (HR) respiration to soil respiration (SR) in a cool-temperate deciduous forest in central Japan. The contribution ratios of RR to SR were 23 % (-16 to 46 %), 11 % (-19 to 61 %), and 115 % (20 to 393 %), as estimated by the Tr, RR, and RE methods, respectively. The contribution ratio showed clear seasonal variation with high values in summer for the Tr method, while they were undetectable for the RR and RE methods because of some methodological problems. These results suggest the Tr method is the best of the three methods used to estimate the contribution ratio of RR and HR to SR in the forest. Annual SR, RR, and HR rates, estimated by the Tr method, were 479, 369, 110 gC m(-2) year(-1), respectively. The seasonal variation of SR was mainly influenced by HR (77 %) throughout the year, while the influence of RR on SR was strongest in summer (46 %). This effect occurred because RR (Q (10) = 7.5) is more sensitive to temperature than HR (Q (10) = 3.2). Also, the contribution of fine RR to total RR was higher than that of coarse RR because of high respiratory activity (Q (10) and R (10)) as well as the large biomass of fine roots. These results suggest that each component of SR responds differently to the same environmental factors and their relative influence on SR changes across the seasons.

    DOI

  • Successional changes in the soil microbial community along a vegetation development sequence in a subalpine volcanic desert on Mount Fuji, Japan

    Shinpei Yoshitake, Masaaki Fujiyoshi, Kenichi Watanabe, Takehiro Masuzawa, Takayuki Nakatsubo, Hiroshi Koizumi

    PLANT AND SOIL   364 ( 1-2 ) 261 - 272  2013.03  [Refereed]

     View Summary

    To study the relationship between vegetation development and changes in the soil microbial community during primary succession in a volcanic desert, we examined successional changes in microbial respiration, biomass, and community structure in a volcanic desert on Mount Fuji, Japan.
    Soil samples were collected from six successional stages, including isolated island-like plant communities. We measured microbial respiration and performed phospholipid fatty acid (PLFA) analysis, denaturing gradient gel electrophoresis (DGGE) analysis, and community-level physiological profile (CLPP) analysis using Biolog microplates.
    Microbial biomass (total PLFA content) increased during plant succession and was positively correlated with soil properties including soil water and soil organic matter (SOM) contents. The microbial respiration rate per unit biomass decreased during succession. Nonmetric multidimensional scaling based on the PLFA, DGGE, and CLPP analyses showed a substantial shift in microbial community structure as a result of initial colonization by the pioneer herb Polygonum cuspidatum and subsequent colonization by Larix kaempferi into central areas of island-like communities. These shifts in microbial community structure probably reflect differences in SOM quality.
    Microbial succession in the volcanic desert of Mt. Fuji was initially strongly affected by colonization of the pioneer herbaceous plant (P. cuspidatum) associated with substantial changes in the soil environment. Subsequent changes in vegetation, including the invasion of shrubs such as L. kaempferi, also affected the microbial community structure.

    DOI

  • Seasonal and Inter-annual Variations in Contribution Ratio of Heterotrophic Respiration to Soil Respiration in a Cool-temperate Deciduous Forest

    M. Tomotsune, R. Masuda, S. Yoshitake, T. Anzai, H. Koizumi

    Journal of Geography   122 ( 4 ) 745 - 754  2013  [Refereed]

     View Summary

    To clarify seasonal and inter-annual variations in the contribution of heterotrophic respiration to soil respiration and influences of such changes on the carbon balance in a forest ecosystem, relationships between respiration rates, soil temperature and soil water content, and the contribution ratio of heterotrophic respiration, were estimated over almost 3 years. Heterotrophic respiration was separated from soil respiration by the trenching method; CO2 emissions from the soil surface were measured along with soil temperature and volumetric soil water content in a cool-temperate deciduous forest from November 2009 to September 2012. Also, the root bag method and two decay models were used to accurately measure CO2 emissions from decomposing dead roots.<br> The soil and heterotrophic respiration responded differently to changes in soil temperature and soil water content. An increase in soil temperature caused increases in respiration, and the response of heterotrophic respiration was lower than that of soil respiration. Also, an increase in the soil water content caused a slight increase in soil respiration and a decrease in heterotrophic respiration. These responses of the respirations to environmental factors caused a decrease in the contribution ratio of heterotrophic respiration with an increase in soil temperature and soil water content. These results suggest that the contribution ratio could experience complex changes when both factors change simultaneously in field conditions.<br> Annual contribution ratios of heterotrophic respiration were estimated at 62% in 2010 and 2011, and the contribution ratio showed seasonal variation ranging from 60% to 100%. The estimated annual heterotrophic respiration rate in 2010 without such seasonal variation ranged from 1.50 to 2.51 kg CO2 m-2 yr-1, and these rates were 96% to 161% of that with seasonal variation (1.56 kg CO2 m-2 yr-1). Also, the annual contribution ratio in 2010 estimated without the effect of soil water content (using respiration and soil temperature curve) was 80%. The resulting annual heterotrophic respiration rate was 2.01 kg CO2 m-2 yr-1, and this rate was 128% of that with the effects of soil water content (using respiration, soil temperature and soil water content curve). In contrast, the effect of inter-annual variation in the contribution ratio on annual heterotrophic respiration rate was small. Therefore, it is important to take into account the seasonal variation in the contribution ratio and the effects of the soil water content on the contribution ratio for more accurate estimation of heterotrophic respiration and net ecosystem production.

    DOI CiNii

  • CO2 flux responses in a cool-temperate grassland to an in situ warming experiment using infrared heaters

    Y. Sekine, S. Yoshitake, R. Masuda, H. Koizumi

    Journal of Geography   122 ( 4 ) 733 - 744  2013  [Refereed]

     View Summary

    The aim of this study is to clarify changes in the ecosystem carbon cycle in response to predicted global warming in various ecosystems including semi-natural grassland. To clarify responses of the whole ecosystem to warming in a semi-natural cool-temperate grassland, we conducted an in situ warming experiment and examined plant growth and CO2 flux responses. Five pairs (control and warmed plots) of Zoysia japonica plots were established. Warmed plots were warmed using infrared heaters from June to November 2009. Once a month, aboveground biomass (AGB) of Z. japonica was estimated using the point frame method. Net ecosystem production (NEP) and ecosystem respiration (Re) were determined from CO2 flux measured using the closed chamber method. Each month, relationships were obtained between photosynthetic photon flux density (PPFD) and NEP (PPFD-NEP curve) and soil temperature (ST) and Re (ST-Re curve). Monthly cumulative NEP, Re, and gross primary production (GPP, sum of NEP and Re) were calculated using these relationships and continuously recorded PPFD and ST data. Although there were some mechanical problems when using infrared heaters, the soil temperature in the warmed plots where infrared heaters worked well was an average of 2.3°C higher than the control plots. This suggests the heating method using infrared heaters is applicable to grassland ecosystems. AGB in the warmed plots tended to be higher (by a maximum of 70%) than in the control plots throughout the experimental period, suggesting that experimental warming affected the phenology and extended the growth period of Z. japonica. Initial slope and light compensation point of PPFD-NEP curve were significantly affected by the warming. Monthly cumulative GPP in the warmed plots tended to be higher (by a maximum of 32%) than in the control plots. This is partly explained by the increased biomass and changed photosynthetic characteristics in the warmed plots. Although not all parameters of the ST-Re curve were affected by warming, monthly cumulative Re in the warmed plots tended to be higher (by a maximum of 35%) than in the control plots. As a result, monthly cumulative NEP in the warmed plots tended to be higher than in the control plots, especially in July (approximately 70% higher) and October (approximately 100% higher). These results suggest that experimental warming affected the carbon cycle in semi-natural cool-temperate grassland by changing the phenology and photosynthetic characteristics of Z. japonica. To promote a better understanding of whole ecosystem responses to predicted warming, a longer term experiment and more detailed descriptions of carbon dynamics including the belowground part of the ecosystem are needed.

    DOI CiNii

  • Responses of Microbial Community to Soil Warming in Warm-Temperate Evergreen Broad-Leaved Forests

    X. Wang, T. Nakatsubo, A. Sasaki, S. Yoshitake, N. Liang, K. Nakane

    Japanese Journal of Forest Environment   55 ( 2 ) 139 - 143  2013  [Refereed]

     View Summary

    To elucidate the effect of climate warming on the soil heterotrophic microbial community in warm-temperate, evergreen broad-leaved forests, we conducted a soil-warming experiment in a secondary forest located in the city of Higashi-Hiroshima in western Japan. We established ten trench plots (1 m × 1 m) with root barriers to prevent root regrowth in the forest. The plots were divided into warming and control treatments. Infrared heaters were used to increase the soil temperature of the warming plots by about 2.5℃ for three years. We used phospholipid fatty acid (PLFA) analysis to examine the composition of the soil heterotrophic microbial community. There were no significant differences in the total content of PLFAs (TotPLFAs) and fungal PLFAs (FungPLFAs) between the warming and control plots. However, warming caused an increase in the amount of bacterial PLFAs (BactPLFAs), the result being a lower ratio of FungPLFAs to BactPLFAs (F/B ratio) in the warming plots. In addition, PLFAs characteristic of gram-negative bacteria increased in the warming plots. The results indicated that the soil heterotrophic microbial community in this warm-temperate, evergreen broad-leaved forest was sensitive to climate warming.

    DOI CiNii

  • Vegetation development and carbon storage on a glacier foreland in the High Arctic, Ny-angstrom lesund, Svalbard

    Shinpei Yoshitake, Masaki Uchida, Toshiyuki Ohtsuka, Hiroshi Kanda, Hiroshi Koizumi, Takayuki Nakatsubo

    POLAR SCIENCE   5 ( 3 ) 391 - 397  2011.09  [Refereed]

     View Summary

    The distribution of organic carbon and its relationship to vegetation development were examined on a glacier foreland near Ny-angstrom lesund, Svalbard (79 degrees N). In a 0.72-km(2) area, we established 43 study plots on three line transects along primary succession from recently deglaciated area to old well-vegetated area. At each plot, we measured the type and percent coverage of vegetation types. The organic carbon content of vegetation, organic soil, and mineral soil samples was determined based on their organic carbon concentration and bulk density. Cluster analysis based on vegetation coverage revealed five types of ground surfaces representing variations in the amounts and allocation patterns of organic carbon. In the later stages of succession, 7%-24% and 31%-40% of organic carbon was contained in the organic and deeper soil layers, respectively. Organic carbon storage in the later stages of succession ranged from 1.1-7.9 kg C m(-2). A larger amount of organic carbon, including ancient carbon in a raised beach deposit, was expected to be contained in much deeper soil layers. These results suggest that both vegetation development and geological history affect ecosystem carbon storage and that a non-negligible amount of organic carbon is distributed in this High Arctic glacier foreland. (C) 2011 Elsevier B.V. and NIPR. All rights reserved.

    DOI CiNii

  • Successional changes in ectomycorrhizal fungi associated with the polar willow Salix polaris in a deglaciated area in the High Arctic, Svalbard

    Masaaki Fujiyoshi, Shinpei Yoshitake, Kenichi Watanabe, Kenichi Murota, Yuki Tsuchiya, Masaki Uchida, Takayuki Nakatsubo

    POLAR BIOLOGY   34 ( 5 ) 667 - 673  2011.05  [Refereed]

     View Summary

    Polar willow (Salix polaris Wahlenb.), a mycorrhizal dwarf shrub, colonizes recently deglaciated areas in the High Arctic, Svalbard. To clarify successional changes in ECM fungi associated with S. polaris after glacier retreat, we examined the diversity and density of ECM fungi in culture and field conditions. Plant and soil samples were collected from three sites of different successional stages in the deglaciated area of Austre Broggerbreen, near Ny-lesund, Svalbard. The successional stages were early stage with newly exposed bare ground (site I), transient stage with scattered colonization of Salix (sites IIa and IIb), and late stage with well-developed vegetation (site III). No ECM colonization on Salix was observed in soils collected from bare ground in early and transient stages (sites I and IIa). However, most Salix individuals showed ECM colonization in soils collected from sites close to Salix colonies in transient and late stages (sites IIb and III). Based on molecular analyses and operational taxonomic unit (OTU: &gt; 95% ITS sequence similarity) delimitations, we identified 15 OTUs/species in eight genera. The dominant OTU/species of ECM fungi identified in the transient and late stages was Geopora sp.1 and Cenococcum sp.1, respectively. In the culture experiment, ECM diversity was greater in late stage (eight OTUs/species) than in transient stage (three OTUs/species). This pattern was consistent with field observations, i.e., late-stage sites contained more OTUs/species of ECM fungi. These results indicate that species diversity of ECM fungi increases and the dominant species changes with the progress of succession after glacier retreat in the High Arctic.

    DOI

  • Colonization of the polar willow Salix polaris on the early stage of succession after glacier retreat in the High Arctic, Ny-Alesund, Svalbard

    Takayuki Nakatsubo, Masaaki Fujiyoshi, Shinpei Yoshitake, Hiroshi Koizumi, Masaki Uchida

    POLAR RESEARCH   29 ( 3 ) 385 - 390  2010.12  [Refereed]

     View Summary

    The polar willow (Salix polaris), predominant in the late successional stage in deglaciated areas of Ny-Alesund, Svalbard, is rarely found in the early stage, when purple saxifrage (Saxifraga oppositifolia) dominates. To elucidate the pattern and the mechanism of successional change from the Saxifraga stage to the Salix stage, we examined the distribution pattern, size structure and habitat conditions of a colonizing Salix population in the seral stage where Salix was invading Saxifraga-dominated sites. The present distribution pattern and aerial photographs taken in the past suggest that Salix colonization at this site commenced within the last 70 years. We found 115 Salix individuals (22 male, 13 female and 80 unknown) in a 30 m 30 m quadrat on the seral stage. Although the largest individual had a size of 2000 cm(2) (length x maximum width), the majority (84%) of individuals were smaller than 100 cm(2). The seedling size distribution, as inferred from the leaf scar number, indicated that annual recruitment was slight. Of the individuals observed about 75% had colonized bare ground; only four individuals grew within Saxifraga colonies. No significant difference was found in soil characteristics (water content, and carbon and nitrogen concentrations) between the seral stage and the earlier stage prior to colonization by Salix. These results suggest that difficulties in seed production, germination and/or seedling establishment of Salix, rather than soil formation by preceding species (Saxifraga), limits the early-stage colonization by Salix.

    DOI

  • Production of biological soil crusts in the early stage of primary succession on a High Arctic glacier foreland

    Shinpei Yoshitake, Masaki Uchida, Hiroshi Koizumi, Hiroshi Kanda, Takayuki Nakatsubo

    NEW PHYTOLOGIST   186 ( 2 ) 451 - 460  2010  [Refereed]

     View Summary

    We examined the photosynthetic characteristics and net primary production of biological soil crusts to evaluate their contribution to the carbon cycle in the High Arctic glacier foreland.
    Biological soil crust samples were collected from a deglaciated area in Ny-Alesund, Svalbard, Norway. Net photosynthetic rates (Pn) and dark respiration rates (R) of biological soil crusts were determined using CO(2) gas exchange rates. We examined the effects of moisture conditions, temperature and photon flux density on Pn and R, and estimated the net primary production by a model based on the relationships between abiotic factors and Pn and R.
    The maximum Pn value occurred at 50% of the maximum water-holding capacity. Pn decreased with increasing temperature and dropped below zero at high temperatures (c. &gt; 13 degrees C). The estimated net primary production of the biological soil crust was greater than the net primary production of other vegetation when based on ground surface area, during the early stage of primary succession. Model simulation showed that the net primary production of the biological soil crust decreased with increasing temperature.
    These results suggest that biological soil crust productivity plays an important role in the carbon cycle during the early stage of succession of the High Arctic glacier foreland, and is susceptible to temperature increases from global warming.

    DOI PubMed

  • Effect of temperature increase on net primary production of cryptogamic plants in the high Arctic tundra ecosystem

    Uchida Masaki, Yoshitake Shinpei, Kanda Hiroshi, Nakatsubo Takayuki

    Plant and Cell Physiology Supplement   2009 ( 0 ) S0071 - S0071  2009

     View Summary

    A significant temperature increase in Arctic tundra ecosystems was observed during 20th century and the temperature increase is expected to be most pronounced in the Arctic at the end of this century. This paper introduces photosynthetic characteristics of three cryptogamic plants (moss, lichen and biological soil crust) on the glacier foreland in the high Arctic, Ny-Alesund, Svalbard, Norway. We constructed a model for estimating the net primary production of the three plants to evaluate an effect of temperature increase on the net primary production.

    DOI CiNii

  • Establishment of soil microbial communities and limiting factors in the early stage of ecosystem development.

    S. Yoshitake

    Hiroshima University    2008.03

  • Organic carbon and microbial biomass in a raised beach deposit under terrestrial vegetation in the High Arctic, Ny-Alesund, Svalbard

    Takayuki Nakatsubo, Shinpei Yoshitake, Masaki Uchida, Masao Uchida, Yasuyuki Shibata, Hiroshi Koizumi

    POLAR RESEARCH   27 ( 1 ) 23 - 27  2008  [Refereed]

     View Summary

    Raised beach deposits are widespread on the north-western coast of Spitsbergen, Svalbard. To elucidate the importance of these deposits in an ecosystem carbon cycle, we measured the concentrations of organic carbon and adenosine 5-triphosphate (ATP; an index of living microbial biomass) in a raised beach deposit found under terrestrial vegetation in Ny-Alesund. A shell in the deposit found at a depth of ca. 20 cm below the ground surface had a (not calibrated) C-14 age of 11080 +/- 140 yr BP, whereas soil organic carbon in the same deposit showed an older C-14 age (22380 +/- 90 yr BP). Organic carbon concentration in the layer of 20-40 cm, belowground was about 1-2%, which was comparable to those in shallower mineral soil layers. Results of ATP analyses suggested that low but non-negligible amounts of microorganisms existed in the deposit. The proportion of biomass carbon to soil organic carbon tended to decrease with increasing depth, suggesting that organic carbon in the deep layer was less available to microorganisms than that in the shallow layers.

    DOI

  • Changes in soil microbial biomass and community composition along vegetation zonation in a coastal sand dune

    Shinpei Yoshitake, Takayuki Nakatsubo

    AUSTRALIAN JOURNAL OF SOIL RESEARCH   46 ( 4 ) 390 - 396  2008  [Refereed]

     View Summary

    We used phospholipid fatty acid (PLFA) analysis to examine the relation of microbial biomass and community composition to vegetation zonation on a coastal sand dune. Soil samples were collected along 3 line transects established from the shoreline to the inland bush. Total PLFA content and PLFA composition of soils were used as indices of total microbial biomass and community composition, respectively. The microbial biomass was much higher in the inland Vitex rotundifolia zone than in the seaside plots. The microbial community composition also differed among the vegetation zones, with a higher contribution of fungal biomarkers in the inland plots. The microbial biomass increased significantly with increasing soil organic matter (SOM) content, but was not correlated with soil salinity. These results suggest that microbial biomass in the coastal sand dune was controlled primarily by the accumulation of SOM. The microbial community composition also changed with SOM content in the seaside plots, but SOM had little effect in the inland plots. These results suggest that the factors limiting the microbial community composition differed with location on the dune.

    DOI CiNii

  • Carbon and nitrogen limitation to microbial respiration and biomass in an acidic solfatara field

    Shinpei Yoshitake, Akiko Sasaki, Masaki Uchida, Yuichi Funatsu, Takayuki Nakatsubo

    EUROPEAN JOURNAL OF SOIL BIOLOGY   43 ( 1 ) 1 - 13  2007.01  [Refereed]

     View Summary

    The solfatara field is a unique ecosystem characterized by harsh conditions such as acidic soils. We examined the respiration rate and phospholipid fatty acid (PLFA) content of solfatara soils and their responses to carbon and nitrogen addition. to determine whether soil microbial respiration and biomass in a solfatara field are limited by substrate availability. Soil samples were collected from locations along a transect across a solfatara field in Oita Prefecture, Japan. The soil in the central part of the solfatara field was highly acidic (pH 2.4) and contained low amounts of carbon and nitrogen. Low basal respiration rates were detected in these soil samples. Measurements of substrate-induced respiration (SIR) and PLFA contents suggested that it was partly attributable to low microbial biomass. Addition of a carbon source (glucose) to the solfatara soil engendered a marked increase in the microbial respiration rate, whereas the nitrogen source (ammonium nitrate) application had no marked effect. Addition of both carbon and nitrogen caused a nearly eightfold increase in the microbial respiration rate and a threefold increase in the total PLFA contents. These results suggest that some acidophilic and/or acid-tolerant microorganisms exist in solfatara soil, but that their respiration and biomass are limited by low substrate availability. (c) 2006 Elsevier Masson SAS. All rights reserved.

    DOI

  • Carbon and nitrogen limitation of soil microbial respiration in a High Arctic successional glacier foreland near Ny-angstrom lesund, Svalbard

    Shinpei Yoshitake, Masaki Uchida, Hiroshi Koizumi, Takayuki Nakatsubo

    POLAR RESEARCH   26 ( 1 ) 22 - 30  2007  [Refereed]

     View Summary

    The hypotheses that carbon and nitrogen availability limit microbial activity, and that the key factors limiting microbes vary along the successional gradient were tested in a High Arctic glacier foreland. We examined the responses of the respiration rate and the phospholipid fatty acid content to the addition of carbon and/or nitrogen. Soil samples were collected from the early stage and late stage of primary succession in the foreland of a glacier near Ny-Alesund, Svalbard. The addition of both carbon (glucose) and nitrogen (ammonium nitrate) engendered an increase in the microbial respiration rate in the early stage of succession. In contrast, the addition of either carbon or nitrogen did not increase the microbial respiration rate. In the late stage of succession the addition of carbon alone, as well as the addition of both carbon and nitrogen, increased the microbial respiration rate. However, neither the addition of carbon nor the addition of nitrogen affected the total phospholipid fatty acid content (an index of microbial biomass) for any soil within 15 days of incubation at 10 degrees C. An increase in the respiration rate was therefore attributed to changes in the physiological activities of the microbial community, such as enzymatic activity. Our study suggests that microbial respiration was limited by the low availability of both carbon and nitrogen in the early stage of succession. Thereafter, nitrogen limitation is mitigated.

    DOI

  • Characterization of soil microflora on a successional glacier foreland in the high Arctic on Ellesmere Island, Nunavut, Canada using phospholipid fatty acid analysis

    S. Yoshitake, M. Uchida, T. Nakatsubo, H. Kanda

    Polar Bioscience   19   73 - 84  2006.01  [Refereed]

     View Summary

    We investigated soil microbial biomass and community structure along a primary successional gradient after deglaciation in the high Arctic, at Ellesmere Island, Nunavut, Canada(80°50'N, 82°45'W). Soil samples were collected from five glacial moraines(M1 to M5) with different developmental periods. Time since the recession of glaciers at M1, M3, and M5 was estimated to be 300, 9000, and over 17000 years, respectively. Soil samples from five points in each moraine were subjected to phospholipid fatty acid(PLFA) analysis. Total PLFA content(an index of microbial biomass) in M1 was significantly lower than those in older moraines(M2-M5), whereas the content remained at an almost constant level from M2 to M5. Significant differences in PLFA composition(an index of microbial community structure) were also observed between M1 and older moraines(M2-M5); the proportion of straight chain saturated fatty acids in M1 was higher than those in older moraines(M2-M5), whereas those of branched fatty acids and unsaturated fatty acids in M1 were lower than those in older moraines(M2-M5). These results suggest that changes of microflora occurred in the early phase of succession after deglaciation and became stable thereafter. Microbial biomass had a positive correlation with soil carbon and nitrogen contents over the successional chronosequence, suggesting that development of soil microflora was affected in part by organic matter accumulation.

    CiNii

  • Soil microbial biomass and limiting factors in a solfatara field

    S. Yoshitake

    Hiroshima University    2005.03

  • Characterization of soil microflora on a successional glacier foreland in Ellesmere Island using phospholipid fatty acid analysis

    Yoshitake Shinpei, Uchida Masaki, Kanda Hiroshi, Nakatsubo Takayuki

    Abstracts of the Annual Meeting of the Ecological Society of Japan   52 ( 0 ) 510 - 510  2005

    DOI CiNii

  • Primary succession and soil development on a glacier foreland in Ny-Alesund, Svalbard

    Ohtsuka Toshiyuki, Uchida Masaki, Yoshitake Shinpei, Nakatsubo Takayuki

    Abstracts of the Annual Meeting of the Ecological Society of Japan   51 ( 0 ) 674 - 674  2004

    DOI CiNii

  • Organic matter decomposition and microbial acitivity in a solfatara field

    S. Yoshitake

    Hiroshima University   50 ( 0 ) 292 - 292  2003.03

    DOI CiNii

▼display all

Books and Other Publications

  • Principles of Terrestrial Ecosystem Ecology, 2nd Edition

    F. Stuart, Chapin III, Pamela A. Matson, Peter M. Vitousek, T. Kato( Part: Joint translator, Decomposition and Ecosystem Carbon Budgets)

    Morikita Publishing  2018.07 ISBN: 9784627261228

Presentations

  • 森林へのバイオ炭施用が土壌微生物群集に及ぼす短期的影響

    吉竹晋平, 佐宗若奈, 安木奈津美, 飯村康夫, 大塚俊之, 近藤美由紀, 友常満利, 藤嶽愓英, 橋本麗優, 小泉博

    日本土壌肥料学会2023年度愛媛大会 

    Presentation date: 2023.09

  • 森林生態系へのバイオ炭の施用~野外散布実験と生態系・土壌圏の応答に関する長期モニタリング~

    吉竹晋平  [Invited]

    関西土壌肥料協議会第101回シンポジウム 

    Presentation date: 2022.12

  • Three-year’s responses of soil nutrients and microbial community to the biochar amendment in a warm-temperate deciduous forest in Japan

    S. Yoshitake, M. Tomotsune, H. Koizumi, T. Ohtsuka

    American Geophysical Union 2019 Fall Meeting 

    Presentation date: 2019.12

  • 冷温帯落葉広葉樹林において樹幹流が土壌圏の炭素動態と微生物群集に及ぼす影響

    吉竹 晋平

    第66回日本生態学会大会 

    Presentation date: 2019.03

  • 石垣島マングローブ林内河川水中における溶存態無機炭素(DIC)濃度の時空間変動

    吉竹 晋平

    日本地球惑星科学連合2018年大会 

    Presentation date: 2018.05

  • 森林生態系における林床へのバイオチャー散布が土壌微生物群集に及ぼす影響

    吉竹晋平, 友常満利, 墨野倉伸彦, 小泉博, 大塚俊之

    第65回日本生態学会大会  (札幌市) 

    Presentation date: 2018.03

  • Effect of biochar amendment on the soil nutrient status and microbial community in a temperate forest, Japan

    S. Yoshitake, M. Tomotsune, N. Suminokura, H. Koizumi, T. Ohtsuka

    2nd International symposium of river basin studies  (Gifu, Japan) 

    Presentation date: 2018.03

  • 微生物から考えてみた

    吉竹 晋平  [Invited]

    第64回日本生態学会大会  (東京) 

    Presentation date: 2017.03

  • Soil in the Takayama site –characterization from microbial perspective-

    S. Yoshitake, T. Ohtsuak

    The 1st of International symposium of river basin studies  (Gifu, Japan) 

    Presentation date: 2017.03

  • 陸域生態系における土壌呼吸と土壌微生物群集

    吉竹 晋平  [Invited]

    日本気象学会2016年度秋季大会  (名古屋) 

    Presentation date: 2016.10

  • 岐阜大学流域圏科学研究センター高山試験地の紹介

    吉竹晋平

    高山市快適環境づくり市民会議平成27年度推進大会  (高山市) 

    Presentation date: 2016.03

  • マングローブ林における有機物分解:潮汐の影響を考慮した堆積物からの無機態炭素放出速度の測定

    吉竹 晋平

    第63回日本生態学会大会  (仙台) 

    Presentation date: 2016.03

  • 草原のリター分解は冬と夏の温暖化にどう応答するのか?

    吉竹 晋平

    第17回高山セミナー  (岐阜) 

    Presentation date: 2016.02

  • 冬と夏の温暖化が草原のリター分解に及ぼす影響

    吉竹 晋平

    2015年度日本生態学会中部地区大会  (高山) 

    Presentation date: 2015.10

  • 冷温帯落葉広葉樹林における窒素無機化速度の時空間変動

    吉竹晋平, 吉竹彩子, 飯村康夫, 大塚俊之

    第62回日本生態学会大会  (鹿児島) 

    Presentation date: 2015.03

  • 落葉広葉樹林(TKYサイト)における窒素無機化速度の時空間変動

    吉竹晋平, 吉竹彩子, 飯村康夫, 大塚俊之

    第16回高山セミナー  (つくば) 

    Presentation date: 2015.02

  • Primary succession of soil microbial community in Ny-Ålesund

    S. Yoshitake, M. Uchida, T. Ohtsuka, T. Nakatsubo

    20th anniversary workshop for terrestrial biological study in Ny-Ålesund, Svalbard  (Tokyo, Japan) 

    Presentation date: 2015.02

  • 高山サイトにおける窒素無機化速度の時空間変動

    吉竹晋平, 吉竹彩子, 飯村康夫, 大塚俊之

    中部山岳地域環境変動研究機構2014年度年次研究報告会  (長野県上伊那郡) 

    Presentation date: 2014.12

  • Spatial distribution of soil microbial characteristics in a cool-temperate deciduous broadleaved forest in Takayama

    S. Yoshitake, A. Yoshitake, Y. Iimura, T. Ohtsuka

    Presentation date: 2014.05

  • 高緯度北極ニーオルスンの氷河後退域における土壌微生物群集の遷移

    吉竹晋平, 内田雅己, 大塚俊之, 中坪孝之

    第61回日本生態学会大会  (広島) 

    Presentation date: 2014.03

  • 高山サイト冷温帯落葉広葉樹林における土壌微生物特性の空間分布

    吉竹晋平, 吉竹彩子, 飯村康夫, 大塚俊之

    中部山岳地域環境変動研究機構2013年度年次研究報告会  (上田) 

    Presentation date: 2013.11

  • わたしたちの森を支える土の中の生き物たち

    吉竹晋平

    高山サイト20周年記念一般公開講演会  (高山) 

    Presentation date: 2013.10

  • Soil microbial responses to three years of experimental warming in a cool temperate grassland in Takayama, Japan

    S. Yoshitake, N. Tabei, Y. Mizuno, H. Yoshida, Y. Sekine, M. Tatsumura, H. Koizumi

    Synthesis Workshop on the Carbon Budget and Forest Ecosystem in the Asian Monitoring Network -The 20th Anniversary of the Takayama Site-  (Takayama, Japan) 

    Presentation date: 2013.10

  • 富士山火山荒原における一次遷移に伴う土壌微生物群集の変化

    吉竹晋平, 藤吉正明, 渡辺憲一, 増沢武弘, 中坪孝之, 小泉博

    日本地球惑星科学連合2013年大会  (千葉) 

    Presentation date: 2013.05

  • 富士山火山荒原の土壌微生物群集に対する基質制限~リン脂質脂肪酸を指標として~

    S. Yoshitake

    (Shizuoka, Japan) 

    Presentation date: 2013.03

  • 高緯度北極氷河後退域における生産者としての土壌クラストの重要性

    吉竹晋平

    第60回日本生態学会大会  (静岡) 

    Presentation date: 2013.03

  • 冷温帯放牧シバ草原における牛糞の供給と分解、そして土壌圏への影響

    吉竹晋平, 五月女皓海, 小泉博

    中部山岳地域環境変動研究機構2012年度年次研究報告会  (高山) 

    Presentation date: 2012.12

  • Belowground ecosystem responses to three years of experimental warming in a cool temperate grassland

    S. Yoshitake, N. Tabei, Y. Mizuno, H. Yoshida, Y. Sekine, M. Tatsumura, H. Koizumi

    The 59th Annual Meeting of ESJ and the 5th EAFES International Congress  (Otsu, Japan) 

    Presentation date: 2012.03

  • Effects of experimental warming on belowground ecosystem in a cool temperate grassland

    S. Yoshitake, N. Tabei, Y. Mizuno, H. Yoshida, Y. Sekine, M. Tatsumura, H. Koizumi

    14th Takayama Seminar held jointly with JSPS-NRF-NDFC A3 Foresight Program Seminar  (Gifu, Japan) 

    Presentation date: 2012.02

  • Successional changes in soil microbial community along the primary succession on a volcanic desert of Mt. Fuji

    S. Yoshitake, M. Fujiyoshi, K. Watanabe, M. Uchida, T. Masuzawa, T. Nakatsubo, H. Koizumi

    The 33rd Symposium on Polar Biology  (Tokyo japan) 

    Presentation date: 2011.11

  • 荒原生態系における土壌微生物群集の制限要因:富士山火山荒原の土壌微生物に対する炭素・窒素・リン制限

    吉竹晋平, 藤吉正明, 中坪孝之, 増沢武弘, 小泉博

    第58回日本生態学会大会  (札幌) 

    Presentation date: 2011.03

  • 放牧シバ草原において牛糞が土壌および植生に与える影響

    S. Yoshitake

    (Gifu, Japan) 

    Presentation date: 2011.02

  • Vegetation development and carbon storage on a glacier foreland in the High Arctic, Ny-Ålesund, Svalbard

    S. Yoshitake, M. Uchida, T. Ohtsuka, H. Kanda, H. Koizumi, T. Nakatsubo

    Second International Symposium on the Arctic Research (ISAR-2)  (Tokyo, Japan) 

    Presentation date: 2010.12

  • Relationship between vegetation development and carbon storage on a glacier foreland in the High Arctic, Ny-Ålesund, Svalbard

    S. Yoshitake, M. Uchida, T. Ohtsuka, H. Kanda, H. Koizumi, T. Nakatsubo

    32nd Symposium on Polar Biology  (Tokyo, Japan) 

    Presentation date: 2010.11

  • 高緯度北極スヴァールバル諸島ニーオルスンの氷河後退域における一次遷移に伴う植生タイプ別純一次生産量の変化

    吉竹晋平, 内田雅己, 村岡裕由, 小泉博, 中坪孝之

    日本地球惑星科学連合2010年大会  (千葉) 

    Presentation date: 2010.05

  • 炭素源資化性から見た富士山火山荒原の土壌微生物群集

    吉竹晋平, 藤吉正明, 内田雅己, 中坪孝之, 増沢武弘, 小泉博

    第57回日本生態学会大会  (東京) 

    Presentation date: 2010.03

  • Project introduction -Carbon sequestration in an Arctic terrestrial ecosystem following rapid glacier retreat: Long-term change and future projection-

    S. Yoshitake

    Japan-Norway Joint Workshop  (Tromsø, Norway) 

    Presentation date: 2010.03

  • 生態系発達の初期過程における土壌微生物群集の変化~荒原生態系の比較から見えてきたこと~

    S. Yoshitake

    (Gifu, Japan) 

    Presentation date: 2010.02

  • 北極域における炭素循環

    S. Yoshitake

    (Toyama, Japan) 

    Presentation date: 2010.01

  • Interactions among plant, soil, and microbes: how microbial diversity and function in soil govern ecosystem processes

    S. Yoshitake  [Invited]

    25th Annual Meeting of the Society of Population Ecology (Kyoto)  (Kyoto, Japan) 

    Presentation date: 2009.10

  • 高緯度北極ニーオルスンの氷河後退域における炭素循環に対する土壌クラストの影響

    吉竹晋平, 内田雅己, 村岡裕由, 小泉博, 中坪孝之

    日本地球惑星科学連合2009年大会  (千葉) 

    Presentation date: 2009.05

  • 富士山火山荒原における一次遷移に伴う土壌微生物群集の変化:リン脂質脂肪酸を指標として

    吉竹晋平, 藤吉正明, 中坪孝之, 増沢武弘, 小泉博

    第56回日本生態学会大会  (盛岡) 

    Presentation date: 2009.03

  • Photosynthetic characteristics of biological soil crusts and effect of temperature increase in a High Arctic glacier foreland in Ny-Ålesund, Svalbard

    S. Yoshitake, M. Uchida, H. Koizumi, H. Kanda, T. Nakatsubo

    A3 Foresight program Gifu Sminar and 11th Takayama Seminar  (Gifu, Japan) 

    Presentation date: 2009.02

  • Photosynthetic characteristics of biological soil crusts in a High Arctic glacier foreland in Ny-Ålesund, Svalbard

    S. Yoshitake, M. Uchida, H. Koizumi, H. Kanda, T. Nakatsubo

    31st Symposium on Polar Meteorology and Glaciology, Polar Biology  (Tokyo, Japan) 

    Presentation date: 2008.12

  • 荒原生態系における土壌微生物群集の制限要因:海岸砂丘の土壌微生物に対する炭素・窒素制限

    吉竹晋平, 中坪孝之

    第55回日本生態学会大会  (福岡) 

    Presentation date: 2008.03

  • 荒原生態系における土壌微生物に対する制限要因:高緯度北極氷河後退域における炭素・窒素制限

    吉竹晋平, 内田雅己, 中坪孝之, 神田啓史

    日本地球惑星科学連合2007年大会  (千葉) 

    Presentation date: 2007.05

  • 海岸砂丘における植生の発達に伴う土壌微生物群集の変化:リン脂質脂肪酸を指標として

    吉竹晋平, 中坪孝之

    第54回日本生態学会大会  (愛媛) 

    Presentation date: 2007.03

  • Soil respiration in a High Arctic glacier foreland in Ny-Ålesund, Svalbard: Is it limited by low carbon and nitrogen availability?

    S. Yoshitake, M. Uchida, T. Nakatsubo, H. Koizumi, H. Kanda

    7th International Conference on Global Change: Connection to the Arctic (GCCA-7)  (Fairbanks, Alaska) 

    Presentation date: 2007.02

  • 荒原生態系における土壌微生物群集の制限要因:高緯度北極氷河後退域の土壌微生物に対する炭素・窒素制限

    吉竹晋平, 内田雅己, 菅尚子, 中坪孝之

    第53回日本生態学会大会  (新潟) 

    Presentation date: 2006.03

  • Factors limiting soil microbial biomass and respiration rate on a successional glacier foreland in the high Arctic, Ny-Ålesund, Svalbard

    S. Yoshitake, M. Uchida, N. Kan, T. Nakatsubo

    The 28th Symposium on Polar Biology  (Tokyo, Japan) 

    Presentation date: 2005.12

  • 北極エルズミア島氷河後退域におけるリン脂質脂肪酸を指標とした土壌微生物相の解析

    吉竹晋平, 内田雅己, 神田啓史, 中坪孝之

    第52回日本生態学会大会  (大阪) 

    Presentation date: 2005.03

  • Characterization of soil microflora on a successional glacier foreland in Ellesmere Island using phospholipid fatty acid analysis

    S. Yoshitake, M. Uchida, T. Nakatsubo, H. Kanda H

    Third international symposium on the arctic research and Seventh Ny-Alesund Scientific Seminar  (Tokyo, Japan) 

    Presentation date: 2005.02

  • 硫気荒原におけるリン脂質脂肪酸を指標とした土壌微生物群集構造の解析

    吉竹晋平, 中坪孝之

    第51回日本生態学会大会  (釧路) 

    Presentation date: 2004.08

  • 硫気荒原における有機物分解と微生物活性

    吉竹晋平, 佐々木晶子, 内田雅己, 船津勇一, 中坪孝之

    第50回日本生態学会大会  (つくば) 

    Presentation date: 2003.03

▼display all

Research Projects

  • 海藻ブルーカーボンを活用したバイオチャーの作出と炭素隔離機能の検証

    日本学術振興会  科学研究費助成事業

    Project Year :

    2024.04
    -
    2027.03
     

    町田 郁子

  • 高緯度北極ツンドラ生態系のレジームシフト:炭素循環研究に基づく機構解明と将来予測

    日本学術振興会  科学研究費補助金(基盤研究B)

    Project Year :

    2022.04
    -
    2027.03
     

    中坪孝之

  • マングローブ林におけるベントス巣穴を介した溶存無機炭素流出の機構解明と定量評価

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    Project Year :

    2023.04
    -
    2026.03
     

    吉竹晋平, 大塚俊之, 友常満利

  • 森林へのバイオチャー散布による炭素隔離効果:リター分解メカニズムの樹種間比較

    日本学術振興会  科学研究費補助金(基盤研究C)

    Project Year :

    2022.04
    -
    2026.03
     

    友常満利

  • 林地へのバイオ炭施用によるCO2放出の削減と生態系サービスの強化に関する研究

    環境再生保全機構  環境研究総合推進費

    Project Year :

    2022.04
    -
    2025.03
     

    吉竹晋平

  • バイオチャーが森林生態系の土壌圏と生態系炭素隔離機能に及ぼす中長期的影響の解明

    日本学術振興会  科学研究費補助金(基盤研究B)

    Project Year :

    2019.04
    -
    2022.03
     

    吉竹 晋平

  • 大気化学と先進的遺伝子解析の融合による森林生態系の温室効果気体動態評価の高精化

    日本学術振興会  科学研究費補助金(基盤研究B)

    Project Year :

    2018.04
    -
    2021.03
     

    村山 昌平

  • バイオチャーが森林生態系の有機物堆積層の構造と機能に与える影響

    日本学術振興会  科学研究費補助金(基盤研究C)

    Project Year :

    2018.04
    -
    2021.03
     

    友常 満利

  • 溶存有機炭素フラックスが森林生態系の土壌圏炭素動態と微生物群集に与える影響の解明

    日本学術振興会  科学研究費補助金(基盤研究C)

    Project Year :

    2016.04
    -
    2019.03
     

    吉竹 晋平

  • バイオチャーを用いた森林における炭素隔離効果と生態系応答機構の解明

    日本学術振興会  科学研究費補助金(基盤研究A)

    Project Year :

    2015.04
    -
    2019.03
     

    小泉 博

  • 植生遷移に伴う落葉広葉樹林生態系機能の環境応答特性の変遷とその変動機構の解明

    日本学術振興会  科学研究費補助金(基盤研究B)

    Project Year :

    2015.04
    -
    2019.03
     

    斎藤 琢

  • タイ王国トラート川河口マングローブ林における土壌生態学的研究

    日本学術振興会  科学研究費補助金(基盤研究B)

    Project Year :

    2015.04
    -
    2018.03
     

    大塚 俊之

  • 草原の落葉分解は冬と夏の温暖化によってどう変化するのか~複合型の野外温暖化操作実験を用いた検証~

    ニッセイ財団  環境問題研究助成

    Project Year :

    2015.10
    -
    2016.09
     

    吉竹 晋平

  • 生態系発達の初期過程における生産者・基質・分解者の関係性とその変化

    日本学術振興会  特別研究員奨励費

    Project Year :

    2009.04
    -
    2012.03
     

    吉竹晋平

     View Summary

    昨年度までに火山荒原(富士山)の一次遷移初期および後期から採取した土壌を用いて基質添加実験を行ってきた。この基質添加実験では3種の炭素源(グルコース・セルロース・リグニン)と窒素源およびリン源を用いている。本年度はこの実験によって得られている土壌サンプルに対して、リン脂質脂肪酸分析を行って基質添加後の微生物バイオマスおよび群集構造の変化について調べた。
    その結果、一次遷移初期の土壌においては、炭素源・窒素源・リン源のいずれも単独の添加では変化は見られなかったが、炭素源を窒素源またはリン源と同時に添加することによって微生物バイオマスの増加および群集構造の変化が認められた。一方、遷移後期の土壌においては、易分解性炭素源であるグルコースについてのみ、炭素源の単独添加によっても微生物バイオマスが増加した。また、遷移初期土壌と同様に、炭素源を窒素源およびリン源と組み合わせて添加することにで、より大きなバイオマス増加や群集構造変化が起こることが示された。今回の添加実験で使用した遷移初期および後期のいずれの土壌に関しても、炭素源・窒素源・リン源を全て添加した際のバイオマス増加量は使用した炭素源の種類によって大きく異なっており、土壌微生物に対する基質制限には基質の「量」に加えて基質の「質」の違いが大きく影響することが明らかとなった。
    これまでに得られている火山荒原以外の荒原生態系の結果を合わせて考察すると、生態系発達の初期過程においては炭素源・窒素源・リン源がいずれも不足しており、このことが、遷移後期に比べて遷移初期において微生物バイオマスが少なく群集構造が異なっている一因であると考えられた。一方、遷移後期においては主に易分解性炭素源の不足によって微生物の増殖などが抑制されている可能性が示された。同時に、遷移後期では窒素源やリン源の不足は二次的な制限要因であることが示唆された。

  • Long-term change and future prediction of the carbon sequestration in an Arctic terrestrial ecosystem following rapid glacier retreat

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2008
    -
    2011
     

    NAKATSUBO Takayuki, UCHIDA Masaki, NASAHARA Kenrou, MURAOKA Hiroyuki, OHTSUKA Toshiyuki, KISHIMOTO Ayaka, KANDA Hiroshi, MOTOHKA Takeshi, HAYASHI Kentaro, WADA Naoya, HIRAO Akira, SASAKI Akiko, FUJIYOSHI Masaaki, YOSHITAKE Shinpei

     View Summary

    This study aims to clarify historical and future changes in carbon cycle and carbon sequestration in the High Arctic terrestrial ecosystem following rapid glacier retreat using a carbon cycle model and remote sensing techniques. We conducted field studies on the distribution of soil organic carbon, processes of glacial retreat and plant colonization on the glacier foreland in Ny-Alesund, Svalbard. Based on these data, response patterns of the carbon cycle and carbon sequestration to future climate change were examined using a carbon cycle model.

  • 生態系発達の初期過程における土壌微生物群集の成立とその制限要因

    日本学術振興会  特別研究員奨励費

    Project Year :

    2007.04
    -
    2008.03
     

    吉竹 晋平

     View Summary

    本年度は、1.火山噴火後に成立する火山荒原において、一次遷移に伴って土壌微生物のバイオマスや群集構造の変化を明らかにすること、2.高緯度北極氷河後退域に見られる寒地荒原の一次遷移初期において、藻類やコケ、地衣などから成る土壌クラストの光合成特性および生産量と、温暖化がそれらに及ぼす影響を明らかにすることを目的とした。
    1.富士山南東側斜面の一次遷移系列に沿って土壌を採取し、リン脂質脂肪酸を指標として土壌微生物のバイオマスおよび群集構造を解析した。その結果、微生物バイオマスの指標である全リン脂質脂肪酸量は土壌有機物量と非常に高い正の相関を示したことから、土壌微生物バイオマスの増加には基質である土壌有機物の蓄積が重要である可能性が示唆された。一方、土壌微生物の群集構造の指標であるリン脂質脂肪酸組成は、裸地への先駆植物の侵入する段階や草本から木本へと植生タイプが変化する段階で大きく変化していたことから、リターや土壌有機物の質的な変化が微生物群集構造に影響を及ぼしている可能性が示された。
    2.スピッツベルゲン島ニーオルスンの氷河後退域から採取した土壌クラストを用いて、様々研な水分・温度・光条件下での光合成・呼吸速度を測定したところ、土壌クラストの光合成速度は温度上昇に非常に敏感に反応して減少することが明らかとなった。次に上記で求めた関係性からモデルを構築し、実際の野外の気象データから純一次生産量を推定したところ、その値は非常に小さかった。モデルにおいて現在の温度+3℃および+6℃条件での純一次生産量をシミュレーションしたところ、クラストの純一次生産量は温暖化によって激減する可能性が示された。
    本年度で得られた成果は、研究例の少ない荒原生態系において生産者(植生)・基質(土壌有機物)・分解者(土壌微生物群集)のそれぞれの変化を相互に関連付けて考える上で非常に重要であると考えられる。

▼display all

Misc

  • Climate change and high arctic terrestrial ecosystem with special reference to carbon cycle

    T. Nakatsubo, M. Uchida, H. Muraoka, H. Noda, S. Yoshitake, M. Uchida

    Chikyu monthly   30 ( 5 ) 240 - 250  2008.07

    Article, review, commentary, editorial, etc. (scientific journal)  

    CiNii

 

Syllabus

▼display all

Teaching Experience

  • カーボンニュートラル社会に向けた自然科学入門(国際関係、人文・学際)

    早稲田大学  

    2024
    -
    Now
     

  • 基礎生物学

    早稲田大学  

    2024
    -
    Now
     

  • 生態学II

    早稲田大学  

    2019.09
    -
    Now
     

  • 環境生態学特論

    早稲田大学  

    2019.09
    -
    Now
     

  • 生態学・実習

    早稲田大学  

    2019.04
    -
    Now
     

  • 生物学演習

    早稲田大学  

    2019.04
    -
    Now
     

  • 生物学実験I

    早稲田大学  

    2019.04
    -
    Now
     

  • 生態学I

    早稲田大学  

    2019.04
    -
    Now
     

  • 生物と環境

    早稲田大学  

    2019.04
    -
    Now
     

  • 総合生命理工学特論A

    2019
    -
    Now
     

▼display all

 

Social Activities

  • 「醸造体験実学講演会」講師

    東京農業大学第三高等学校附属中学校  中学校生徒対象「醸造体験実学講演会」 

    2023.04
     
     

  • 講演会講師

    日本木炭新用途協議会  日本木炭新用途協議会講演研修会 

    2022.07
     
     

  • 科学総合コースセミナー講師

    兵庫県立小野高校 

    2021.11
     
     

  • 科学総合コースセミナー講師

    兵庫県立小野高校 

    2021.03
     
     

  • 研究交流会講師

    東京女子医科大学・早稲田大学  研究交流会 

    2021.03
     
     

  • 出前授業講師

    早稲田大学高等学院  現代の生命科学 

    2020.06
     
     

  • 科学総合コースセミナー講師

    兵庫県立小野高校 

    2019.10
     
     

  • モデル授業講師

    早稲田大学高等学院  モデル講義 

    2019.05
     
     

  • 科学総合コースセミナー講師

    兵庫県立小野高等学校  (兵庫県立小野高等学校) 

    2018.07
     
     

  • 講演会講師

    早稲田大学  講演会  (早稲田大学先端生命医科学センター) 

    2018.06
     
     

     View Summary

    1

  • 科学総合コースセミナー講師

    兵庫県立小野高等学校  (兵庫県立小野高等学校) 

    2017.06
     
     

     View Summary

    1

▼display all

Sub-affiliation

  • Faculty of Science and Engineering   Graduate School of Advanced Science and Engineering

  • Affiliated organization   Global Education Center

Research Institute

  • 2022
    -
    2024

    Waseda Research Institute for Science and Engineering   Concurrent Researcher

  • 2022
    -
    2024

    Waseda Center for a Carbon Neutral Society   Concurrent Researcher

Internal Special Research Projects

  • 亜熱帯マングローブ林堆積物における有機物分解と微生物群集

    2023   月本将太郎

     View Summary

     沖縄県石垣島の小規模マングローブにおける炭素循環の解明のためには、堆積物中の有機物の分解によって生成・放出される溶存無機炭素(DIC)の生成メカニズムや流出経路を明らかにすることが重要であると考えられた。本研究では当初有機物分解プロセスそのものに焦点を当てて実験を行う予定であったが、現地の堆積物に見られる非常に高い空間的不均一性、すなわち底生生物(ベントス)の造巣行動によって作られる巣穴が多数点在することが、有機物分解の結果生じるDICの河川・海洋への流出に大きな影響を与えると思われた。そのため研究計画を一部変更・発展させ、現地における底生生物による巣穴の基礎的な情報を取得すること、そしてその巣穴内部へのDIC流出過程の解明を試みた。 石垣島のマングローブ林において、樹脂をカニ穴に流し込むことでその型取りを行い、その形状や体積、表面積を解析した。その結果、入り口の直径がわずか2–3 cmの巣穴であっても、地下部には表面積で3,600–4,900 cm2、体積で1,400–2,500 cm3もの空間が広がっていることが明らかとなった。また、生物種によって巣穴の形状は異なっていた。インターバルカメラを用いて地表面に多数存在するこれらの巣穴を注意深く観察したところ、約40%の巣穴では潮位変動に同期して巣穴内部の水面が上下していたが、残りの約60%の巣穴では単純に潮位変動に応じて上下するのではなく、上げ潮時に地表面に満ちてきた海水が巣穴上部から流れ込む様子が見られた。また、巣穴内部の水を経時的に採取してDIC濃度を分析したところ、DIC濃度が時間とともに増加する様子が確認できた。これらの結果から、干潮時においてもベントス巣穴内部に海水が滞留し、そこに巣穴の壁面を介して堆積物中の高濃度DICが巣穴内部の水に放出され、それが満潮時に河川や海洋に流出する可能性が強く示唆された。

  • 亜熱帯マングローブ林からの海洋への物質流出過程に関する研究

    2022   伊藤河聞

     View Summary

    石垣島の小規模マングローブ流域において、河口部での河川断面積の測定と経時的な水位および流量測定を行い、これらをもとに河川流量の算出を試みたが、現場の河口部底質は砂質であったため、地中を通って流出する河川水の定量は困難であることが明らかとなった。そこで本研究課題では、河口部で採取した水試料を分析し、河口から海洋に向けて流出する溶存態有機炭素・無機炭素の濃度情報を取得した。また、域内から堆積物サンプルを採取し、室内実験によって有機物分解速度を測定した。その結果、海水に覆われる冠水条件下でも有機物分解が進行していること、無視できない量の溶存無機炭素が水中に放出されることが明らかとなった。

  • マングローブ林における有機物分解過程の解明

    2021   伊藤

     View Summary

    マングローブ林における有機物無機化速度を明らかにするため、林内の堆積物を採取し、一般的物理化学性の分析と、干出時(通気法)および冠水時(水中密閉法)における無機態炭素放出速度の測定を行った。干出時の無機化速度は有機物含量やシルト含量が高い場所で大きく、冠水時における溶存無機炭素(DIC)の生成速度は、有機物含量や含水率が高い川沿いの地点で大きかった。マングローブから沿岸に流出する炭素量を推定するため、河口部でDICと溶存有機炭素(DOC)濃度を測定したところ、いずれも干潮時に大きく増加しており、マングローブ域から多くの溶存炭素が海洋へ輸送されていることが示された。

  • 森林生態系における土壌微生物群集特性の空間的不均一性の解明

    2020   西貝竜太

     View Summary

    森林における土壌微生物群集の空間的不均一性の原因の1つには、植物から供給されて微微生物の基質となる有機物の量や質が空間的に不均一であることが挙げられる。本研究では、鉱質土壌に供給される有機物として特に樹幹流等に含まれる溶存有機態炭素(DOC)に着目し、それらが微生物群集に及ぼす影響について調べた。野外で採取した樹幹流等を実験室内で土壌に添加し、微生物呼吸や窒素無機化速度などの応答を調べたところ、樹幹流またはリター滲出液、あるいは樹種によって微生物群集は異なる応答を示したことから、森林内での樹木位置や樹種の違いが、DOC供給を介して土壌微生物群集の空間的不均一性に寄与している可能性が示唆された。

  • 植物根呼吸の日変化とその変動要因の解明

    2019   今吉健斗

     View Summary

    根呼吸は採取した根をチャンバーに入れて実験室で測定されることが多いが、この方法では地上部との連携を無視しているという問題があった。本研究では非切断根の連続測定法について検討を行った。まず野外で非切断根の呼吸を測定する方法を検討したが、多くの技術的課題により連続測定を行えるには至らなかった。そこで、実験室環境下でモデル植物の非切断細根の連続測定を試み、光・温度環境への根呼吸の応答性解明を行った。その結果、実験室環境下では非切断細根の連続測定が可能であり、その根呼吸が光強度に対して明瞭に応答することが示された。今後はこのシステムを用いて野外植物の根呼吸の連続測定を実施する予定である。