SAITO, Yu

写真a

Affiliation

Faculty of Science and Engineering, School of Creative Science and Engineering

Job title

Assistant Professor(without tenure)

Degree 【 display / non-display

  • 京都大学   博士(理学)

Research Experience 【 display / non-display

  • 2019.04
    -
    Now

    Waseda University   School of Creative Science and Engineering

  • 2017.04
    -
    2019.03

    Doshisha University

  • 2015.10
    -
    2019.03

    Research Institute for Humanity and Nature

  • 2016.04
    -
    2018.03

    Kyoto Sangyo University

  • 2014.04
    -
    2015.03

    Kochi University   Center for Advanced Marine Core Research, Kochi University

display all >>

 

Research Areas 【 display / non-display

  • Biogeosciences   堆積学・同位体地球化学

Research Interests 【 display / non-display

  • hyperpycnite

  • provenance

  • isotope

  • sediment

Papers 【 display / non-display

  • Evaluation of origin-depended nitrogen input through atmospheric deposition and its effect on primary production in coastal areas of western Kyusyu, Japan

    Yu Umezawa, Kanae Toyoshima, Yu Saitoh, Shigenobu Takeda, Kei Tamura, Chiaki Tamaya, Akira Yamaguchi, Chikage Yoshimizu, Ichiro Tayasu, Kazuaki Kawamoto

    Environmental Pollution     118034 - 118034  2021.08

    DOI

  • Supply ranges of stone blocks used in masonry bridges and their construction period along the East Royal Road in the Khmer Empire, Cambodia

    Etsuo Uchida, Yuichiro Sakurai, Rathborith Cheng, Ichita Shimoda, Yu Saito

    Heritage Science   8 ( 1 )  2020.12

     View Summary

    <jats:title>Abstract</jats:title><jats:p>During the Angkor period, there were five Royal Roads linking the capital city of Angkor with provincial principal cities. Seven Temples d’étape, six Fire Shrines, and 25 masonry bridges were constructed along the East Royal Road to Preah Khan of Kompong Svay. We conducted measurements of magnetic susceptibility and chemical composition of laterite blocks and magnetic susceptibility of sandstone blocks used for the construction of the bridges to determine the supply ranges of the stone blocks and the construction ages based on the results obtained in this study and previous studies of Temples d’étape and Fire Shrines. The results suggest that most of the sandstone blocks for the bridge balustrades were supplied from quarries in the southeastern foothills of Kulen Mountain, but that the bridges close to Preah Khan of Kompong Svay have sandstone balustrades supplied from nearby quarries. In contrast, cluster and principal component analyses and t-tests using data for chemical composition and magnetic susceptibility of laterite blocks revealed that there were five sources of supply. These results elucidated that the supply ranges of laterite blocks were narrower than those of the sandstone blocks. Judging from magnetic susceptibilities, supply ranges, shapes, orientations of bedding planes, and stacking methods of the stone blocks, it was concluded that the construction age of the bridges is highly likely to have been in the early Angkor Wat period.</jats:p>

    DOI

  • Sr-Nd-Pb isotope systematics of fine sediments from the modern rivers in SW Japan: Implications for sediment provenance of the Northwest Pacific

    Yu Saitoh, Masaharu Tanimizu, Tsuyoshi Ishikawa

    Journal of Asian Earth Sciences: X   3   100029 - 100029  2020.06  [Refereed]

    DOI

  • Geographic variation of Sr and S isotope ratios in bottled waters in Japan and sources of Sr and S

    Takanori Nakano, Katsuyuki Yamashita, Atsushi Ando, Soichiro Kusaka, Yuh Saitoh

    Science of The Total Environment   704   135449 - 135449  2020.02  [Refereed]

     View Summary

    © 2019 Elsevier B.V. The geographic distribution of the stable isotope ratio of Sr (87Sr/86Sr) is useful for identifying the provenance of drinking water, organisms, and agricultural products. To explore how environmental factors influence this ratio, we determined the 87Sr/86Sr, sulfur isotope ratio (δ34S), and elemental composition of 208 commercially available bottled waters in Japan, and compared them with the 87Sr/86Sr values of groundwater, rainwater, rocks, and vegetables from similar localities. We classified the bottled waters into seven categories based on the geology of their source aquifers. The 87Sr/86Sr and concentrations of several elements (Ca, K, Si, Rb, and Ba) of the bottled waters differed with the aquifer rock type and were well correlated with the 87Sr/86Sr of reported spring waters, indicating that bottled water, like other groundwater, reflects the lithology and chemistry of its aquifer. The 87Sr/86Sr of bottled water, taken as a proxy for groundwater, showed regional variations consistent with those of rocks and vegetables, demonstrating that an 87Sr/86Sr map of water and agricultural products has value for determining the production areas of these substances. However, the value and range of 87Sr/86Sr differed among these three materials, and the degree of the difference between groundwater and rock depended on the rock type. An analysis of geochemical data from rocks and rainwater suggests that groundwater contains Sr and additional S derived from atmospheric sources such as rainwater and sea salt aerosols. The atmospheric contribution of Sr to groundwater is greatest in areas of siliceous sedimentary rocks with low Sr concentrations and high resistance to weathering. A weak correlation of δ34S of bottled waters with 87Sr/86Sr indicates the usefulness of maps of combined Sr and S isotope ratios for groundwater provenance. This study shows that for accurate provenance determinations of groundwater, organisms, and agricultural products, it is essential to better quantify the contributions of Sr and S from the atmosphere as well as from rocks and human activities.

    DOI PubMed

  • The Effects of Differences in Vegetation on Calcium Dynamics in Headwater Streams

    Ohta, T., Shin, K.-C., Saitoh, Y., Nakano, T., Hiura, T.

    Ecosystems   21 ( 7 ) 1 - 14  2018  [Refereed]

     View Summary

    Although organisms can alter dynamics of elements in ecosystems via physiological results, the effects of tree species on ecosystem nutrient dynamics are highly uncertain. A four-fold variation in the calcium concentrations of streams, soils and leaf litters were caused by the planting of Cryptomeria japonica in south-central Japan. In this study, we examined how the calcium dynamics were affected by the planting of C. japonica through strontium isotope analysis. We predicted the planting of C. japonica would result in the calcium concentration increasing because of the significant dissolution of calcium from bedrock. In a forest ecosystem, calcium is usually derived from precipitation and bedrock weathering, and their relative contributions can be estimated using a strontium isotope mixing model. Therefore, we collected stream water, litter, soil, precipitation and bedrock samples from 17 sites in catchments dominated by C. japonica plantation or evergreen broad-leaved forest
    after collection, we analyzed the sample chemical compositions and strontium isotope ratios. The calcium concentrations in the stream water and the water-soluble calcium in the soil were significantly higher at sites dominated by C. japonica than at broad-leaved forest sites. Strontium isotope analysis indicated that there was more calcium from the bedrock present in stream water at sites dominated by C. japonica than in stream water at broad-leaved forest sites. Our results showed that watershed-scale dynamics of calcium and other cations can be altered by the type of vegetation in a catchment due to the effects of vegetation on the supply of calcium from bedrock.

    DOI

display all >>

Misc 【 display / non-display

  • The Effects of Differences in Vegetation on Calcium Dynamics in Headwater Streams

    Tamihisa Ohta, Ki-Cheol Shin, Yu Saitoh, Takanori Nakano, Tsutom Hiura

    Ecosystems   21   1 - 14  2018.02

     View Summary

    Although organisms can alter dynamics of elements in ecosystems via physiological results, the effects of tree species on ecosystem nutrient dynamics are highly uncertain. A four-fold variation in the calcium concentrations of streams, soils and leaf litters were caused by the planting of Cryptomeria japonica in south-central Japan. In this study, we examined how the calcium dynamics were affected by the planting of C. japonica through strontium isotope analysis. We predicted the planting of C. japonica would result in the calcium concentration increasing because of the significant dissolution of calcium from bedrock. In a forest ecosystem, calcium is usually derived from precipitation and bedrock weathering, and their relative contributions can be estimated using a strontium isotope mixing model. Therefore, we collected stream water, litter, soil, precipitation and bedrock samples from 17 sites in catchments dominated by C. japonica plantation or evergreen broad-leaved forest
    after collection, we analyzed the sample chemical compositions and strontium isotope ratios. The calcium concentrations in the stream water and the water-soluble calcium in the soil were significantly higher at sites dominated by C. japonica than at broad-leaved forest sites. Strontium isotope analysis indicated that there was more calcium from the bedrock present in stream water at sites dominated by C. japonica than in stream water at broad-leaved forest sites. Our results showed that watershed-scale dynamics of calcium and other cations can be altered by the type of vegetation in a catchment due to the effects of vegetation on the supply of calcium from bedrock.

    DOI

  • 溶存物質および生物の多元素同位体組成が示す生態系情報:東北太平洋岸地域の例

    陀安一郎, 由水千景, 松林順, 加藤義和, 長田穣, 奥田昇, 斉藤有, 申ギチョル, 中野孝教, 神松幸弘, 近藤倫生, 冨樫博幸, 天野洋典, 栗田豊

    日本生態学会大会講演要旨(Web)   63th   P2‐443 (WEB ONLY)  2016

    J-GLOBAL

  • Coastal barrier dune construction during sea-level highstands in MIS 3 and 5a on Tottori coast-line, Japan

    Tamura, T., Kodama, Y., Bateman, M.D., Saitoh, Y., Watanabe, K., Matsumoto, D., Yamaguchi, N.

    Palaeogeography, Palaeoclimatology, Palaeoecology   308 ( 3-4 ) 492 - 501  2011

     View Summary

    The southern coast of Japan Sea exhibits a number of Late Pleistocene coastal barrier dunes, where the sediment record potentially provides important evidence for the palaeoenvironmental history of East Asia. The lack of direct dating of these barrier dunes, however, has veiled relationships between dune deposition, sea level, and other controlling factors. Quartz single aliquot regenerative optically-stimulated luminescence (OSL) dating was applied to the Late Pleistocene barrier dune at the Tottori coast, southern central Japan Sea. We investigated a borehole drilled in a continuous ground-penetrating radar (GPR) profile of the dune and an outcrop excavation, where there has been recognised a sedimentary succession exposed of the Pleistocene dune sand, palaeosol, Daisen-Kurayoshi Pumice (DKP) tephra, palaeosol, and Holocene dune sand, in ascending order. The gradual transition from the Pleistocene dune sand to palaeosol indicates a termination of the Late Pleistocene dune activity. Five OSL ages from the uppermost Pleistocene dune overlap within the period 48.2-51.4 ka, which confirms that both deposition and termination of the dune occurred in early to mid Marine Isotope Stage (MIS) 3. Another OSL age from the lower section was 77.7 +/- 6.1 ka, and indicates an earlier depositional stage in late MIS 5a. These reveal that the coastal dune deposition occurred in relation to the sea-level highstands. It would appear that a sea level of c. -50 m relative to the present was the threshold for the dune activation. Morphology and sediment distribution of the modern shelf off the Tottori coast suggest that the sea-level lower than -50 m leads to increasingly unfavourable conditions for coastal dune activity due to longer sediment transport distances and decreased sediment supply. These results have implications for the Late Pleistocene barrier dune along the southern Japan Sea coast and suggest that other dunes, correlated with Tottori based on the DKP tephra, possibly would also have experienced a similar termination in relation to the sea-level fall from mid MIS 3. Results also demonstrate that the depositional setting of the Late Pleistocene dunes was different from those constructed in the Holocene due to the lower interstadial sea-level highstands and resultant longer distance to the shore during MIS 3 and 5a. As a result, the Pleistocene dune exhibits less pronounced stratification and in finer grain size than the outer Holocene dune ridge, where sand is directly fed from the shore. The grain size of the inner Holocene dune ridge in contrast is almost identical to the Pleistocene dune, suggesting that the inner ridge partly consists of sand reworked from the Pleistocene dune. (C) 2011 Elsevier B.V. All rights reserved.

    DOI

  • 水路実験による堆積物挙動

    増田富士雄, 成瀬元, 高川智博, 齋藤有, 山口直文

    日本地質学会第112年学術大会(京都)見学旅行案内書     161–173  2005

    Lecture material (seminar, tutorial, course, lecture, etc.)  

Awards 【 display / non-display

  • 論文賞

    2016.03   日本堆積学会  

 

Syllabus 【 display / non-display

display all >>