Yasuhiko T. Yamaguchi

Organic Biogeochemist

Overview

Yasuhiko T. Yamaguchi, Ph.D.

Researcher, Lake Biwa Environmental Research Institute (LBERI)

I'm interested in the roles of the biosphere and organic matter in the biogeochemical cycles in aquatic environments (both marine and freshwater). My main research tools are organic geochemistry and isotope geochemistry, including compound-specific isotope analysis of amino acids, enantiomer analysis of amino acids, molecular size quantification, size-based isolation of organic matter, etc.

(Last update: Mar/1/2022)

News

  • Our new 4-year research project on the organic matter dynamics in hypolimnion (PI: Shin'ichi Nakano at Kyoto Univ.) is funded by JSPS (Apr 2022 - Mar 2026)!

  • Our new 3-year research project on the mechanisms underlying the persistence of aquatic dissolved organic matter (PI: Morimaru Kida at Kobe Univ.) is funded by JSPS (Apr 2022 - Mar 2025)!

  • Our new 3-year research project on the influence of anoxia on the elution of dissolved organic matter from lake sediments (PI: Yasuro Fuse at Kyoto Inst. Tech.) is funded by JSPS (Apr 2022 - Mar 2025)!

PAST ACTIVITIES

2021

  • Nov/30/2021 Oral presentation about the size-reactivity relationship of freshwater DOM at the Annual Meeting of the Japanese Association of Organic Geochemists 2021 (Nov/29-30, virtual & Sapporo).

  • Nov/27/2021 Oral presentation about the size-reactivity relationship of freshwater DOM at the Annual Meeting of the Japanese Humic Substances Society 2021 (Nov/26-27, virtual).

  • Sep/10/2021 Oral presentation about a new correction method of D/L ratio of amino acids at the Annual Meeting of the Geochemical Society of Japan 2021 (Sep/6-10, virtual).

  • Aug/27/2021 Oral presentation at SIL 2021 (Aug/22-27, virtual) about the size-reactivity relationship of freshwater DOM.

  • Jun/27/2021 Oral presentation at ASLO 2021 Aquatic Sciences Meeting (June/22-27, virtual) about the size-reactivity relationship of freshwater DOM.

  • Jun/4/2021 Oral presentation about the size-reactivity relationship of freshwater DOM at Japan Geoscience Union Meeting 2021 (May/30-June/6, virtual).

  • Apr/1/2021 Our new 3-year research project "New development of dynamics and characterization dissolved organic nitrogen in freshwater environments by molecular weight fractionation using nanofiltration" (PI: Kazuhide Hayakawa at LBERI) is also funded by JSPS (Apr 2021 - Mar 2024)!

  • Apr/1/2021 My new 3-year research project "Microbial Nitrogen Pump: Bacterial semi-labile dissolved organic nitrogen as a nutrient transport pathway in aquatic systems" is funded by JSPS (Apr 2021 - Mar 2024)!

  • Mar/19/2021 In FY2020, I participated in 11 research cruises in Lake Biwa using R/V Biwakaze.

2020

  • Nov/19-21/2020 Oral presentation about bacteria-derived DON at the Annual Meeting of the Geochemical Society of Japan 2020 (virtual).

  • Oct/12/2020 I started serving as a member of the Information & System Committee of the Japan Geoscience Union.

  • Jul/1/2020 I started serving as an associate editor of Researches in Organic Geochemistry.

  • Jun/21-26/2020 Poster presentation about "minor" D-amino acids in aquatic DOM at Goldschmidt2020 (virtual).

  • Mar/28/2020 In FY2019, I participated in 10 research cruises in Lake Biwa using R/V Biwakaze.

  • Jan/1/2020 I started serving as an associate editor of Geochemical Journal.

2019

  • Sep/20/2019 Main parts for custom-made ultrafiltration systems and solid-phase extraction systems (pumps, membrane housings, etc.) have arrived in my lab! I will develop methods for the isolation of HMW DOM and LMW DOM.

  • Sep/17-19/2019 Oral presentation about molecular-size distribution and biodegradation kinetics of lake DOM at the Annual Meeting of the Geochemical Society of Japan 2019 (Tokyo, Japan).

  • Sep/6/2019 A new HPLC system (Agilent 1260 Infinity II) and a charged aerosol detector (CAD: ThermoScientific Corona Veo SD) have been installed in my lab! I will use it mainly for the purification of amino acids for the isotope analysis.

  • Aug/28-29/2019 Oral presentation about D-amino acids of DOM in various aquatic environments at the 37th Japan Organic Geochemistry Symposium (Kanazawa, Japan).

  • Aug/5/2019 River water sampling at Yasu River for a long-term degradation experiment.

  • May/26-30/2019 Oral presentation about D-amino acids in lake DOM at Japan Geoscience Union Meeting 2019 (Makuhari, Japan).

  • Apr/1/2019 Our new 3-year research project "Microbial loop, dominant food chain in lake hypolimnion" (PI: Shin-ichi Nakano at Kyoto Univ.) is funded by JSPS!

  • Mar/28/2019 My research project of D-amino acids in lake DOM is funded for 1 more year (until Mar/2020) by Lake Biwa-Yodo River Water Quality Preservation Organization (BYQ)!

  • Mar/11/2019 A new fluorometer for DOM 3D-EEM measurements (Aqualog, Horiba Scientific) has been installed in my lab!

  • Mar/1/2019 Poster presentation about D-amino acids in lake DOM at the Lake Biwa Seminar (Otsu, Japan).

  • Feb/26-28/2019 I visited NIES for stable carbon isotope analysis of organic matter samples.

  • Feb/15/2019 Invited talk about organic nitrogen in aquatic environments at the 304th CER Seminar of Kyoto University (Kyoto, Japan).

2018

  • Nov/17-18/2018 Poster presentation about degradation and composition of suspended PON in a lake and the ocean at the 8th Symposium on Environmental Isotope Study (Kyoto, Japan).

  • Nov/17-18/2018 Oral presentation about degradation and composition of suspended PON in a lake and the ocean at the 2018 Biogeochemistry symposium (Kyoto, Japan).

  • Nov/8-9/2018 I visited JAMSTEC for discussion about methods for amino acids analysis.

  • Oct/8/2018 Oral presentation about degradation and composition of suspended PON in a lake and the ocean at the 83th Annual Meeting of the Japanese Society of Limnology (Okayama, Japan).

  • Sep/10-13/2018 Oral presentation about degradation and composition of suspended PON in a lake and the ocean at the Annual Meeting of the Geochemical Society of Japan 2018 (Okinawa, Japan).

  • Aug/31/2018 I was awarded for the Taguchi Award, which honors an early-career scientist, of the Japanese Association of Organic Geochemists for my works on "Methods development and organic geochemical studies of dynamics of organic nitrogen in aquatic environments using amino acids nitrogen isotopes"!

  • Aug/31/2018 Oral presentation about decoupling of DON & PON sources in the surface oceans at the 36th Japan Organic Geochemistry Symposium (Tokyo, Japan).

  • Aug/27/2018 Started a long-term degradation experiment of lake water POM & DOM to track changes of isotopic and organic geochemical parameters.

  • Jun/15/2018 A co-authored paper (Ijiri et al. 2018), which revealed the biogeochemistry of deep subseafloor of a submarine mud volcano, has been published in Science Advances.

  • Apr/2/2018 My new 3-year research project "Development of high-precision nitrogen isotope analysis as a new index of dissolved organic matter sources in aquatic environments" is funded by JSPS!

  • Apr/2/2018 My new 1-year research project "Bacterial contribution to dissolved organic matter pools in lakes: Development of a quantification method using enantiomeric biomarkers" is funded by Lake Biwa-Yodo River Water Quality Preservation Organization (BYQ)!

  • Mar/29/2018 Website launched!