HOME | Resarch | Publication-YC


  • Korenaga T., Suzuki Y., Chikaraishi Y. (2019) Biochemical stable isotope analysis for advances in food authenticity. Engineering Tools in the Beverage Industry, 1st edition, Vo. 3 The Science of Beverage (Grumezesc A., Holban A.M. eds), Woodhead Publishing, pp. 209-227.
  • Chikaraishi Y. (2014) 13C/12C Signatures in plants and algae. Treatise on Geochemistry, second edition, Vol.12 Organic Geochemistry (Falkowski P, Freeman K.H. eds), Elsevier, pp. 95-123.
  • Takano Y., Chikaraishi Y., Ohkouchi N. (2010) Enantiomer-specific isotope analysis (ESIA) of D- and L-alanine: nitrogen isotopic hetero- and homogeneity by microbial and chemical processes. In Earth, Life, and Isotopes, Ohkouchi N., Tayasu I., Koba K (eds), Kyoto University Press, pp. 387-402.
  • Chikaraishi Y., Takano Y., Ogawa N.O., Ohkouchi N. (2010) Instrumental optimization for compound-specific nitrogen isotope analysis of amino acids by gas chromatography/combustion/isotope ratio mass spectrometry. In Earth, Life, and Isotopes, Ohkouchi N., Tayasu I., Koba K (eds), Kyoto University Press, pp.367-386.
  • Chikaraishi Y., Ohkouchi N. (2010) An improved method for precise determination of carbon isotopic composition of amino acids. In Earth, Life, and Isotopes, Ohkouchi N., Tayasu I., Koba K (eds), Kyoto University Press, pp.355-366.
  • Ohkouchi N., Chikaraishi Y., Kashiyama Y., Ogawa, N.O. (2010) Isotopomer of chlorophyll nucleus: Theories and an application. In Earth, Life, and Isotopes, Ohkouchi N., Tayasu I., Koba K (eds), Kyoto University Press, pp. 271-290.
  • Chikaraishi Y., Ogawa N.O., Ohkouchi N. (2010) Further evaluation of the trophic level estimation based on nitrogen isotopic composition of amino acids. In Earth, Life, and Isotopes, Ohkouchi N., Tayasu I., Koba K (eds), Kyoto University Press, pp.37-51.
  • Kashiyama Y., Ogawa N.O., Chikaraishi Y., Kashiyama N., Sakai S., Tanabe K., and Ohkouchi N. (2010) Reconstructing the life history of modern and fossil nautiloids based on the nitrogen isotopic composition of shell organic matter and amino acids. In Cephalopods - Present and Past, Tanabe K., Shigeta Y., Sasaki T., and Hirano H. (eds), pp.67-75.




  • Furukawa Y., Iwasa Y., Chikaraishi Y. (2021) Synthesis of 13C-enriched amino acids with 13C-depleted insoluble organic matter in a formose-type reaction in the early solar system. Science Advance 7, eabd3575.
  • Fujiwara Y., Kawato M., Poulsen J.Y., Ida H., Chikaraishi Y., Ohkouchi N., Oguri K., Gotoh S., Ozawa G., Tanaka S., Miya M., Sado T., Kimoto K., Toyofuku T., Tsuchida S. Discovery of a colossal slickhead (Alepocephaliformes: Alepocephalidae): an active-swimming top predator in the deep waters of Suruga Bay, Japan. Scientific Reports 11, 1-16.
  • Ishikawa N.F., Ogawa N.O., Chikaraishi Y., Yamaguchi M., Fujikura K., Miyairi Y., Yokoyama Y., Nagata T., Ohkouchi N. (2021) Influences of ocean currents on the diets of demersal fish communities in the western North Pacific revealed by their muscle carbon and nitrogen isotopic compositions. Frontiers in Marine Science 8, 465.


  •  Mucci N.C., Jones K.A., Cao M. Wyatt II M.R., Foye S., Kauffman S., Taufer M., Chikaraishi Y., Steffan S., Campagna S., Goodrich-Blair H. (2021) Chemical ecology of an apex predator life cycle. BioRxiv. doi: https://doi.org/10.1101/2021.02.13.430781


  • Morra K.E., Chikaraishi Y., James H.F., Rossman S., Wiley A.E., Ostrom P.H. (2020) Seasonality of decadal-scale trophic declines and nutrient regime shifts in the Laysan Albatross and Newell's shearwater. Marine Ecology Progress Series, in prep.
  • Xing D., Choi B., Takizawa Y., Fan R., Sugaya S., Tsuchiya M., Ohkouchi N., Chikaraishi Y. (2020) Trophic hiearchy of coastal marine fish communities viewed via compound-specific isotope analysis of amino acids. Marine Ecology Progress Series 652, 137-144.
  • Takizawa Y., Takano Y., Choi B., Dharampal P.S., Steffan S.A., Ogawa N.O., Ohkouchi N., Chikaraishi Y. (2020) A new insight into isotopic fractionation associated with decarboxylation in organisms: implications for amino acid isotope approaches in biogeoscience 7, 50.
  • Choi B., Lee C., Takizawa Y., Chikaraishi Y., Oh. H.-J., Chang K.-H., Jang M.-H., Kim H.-W., Lee K.-L., Shin K.-H. (2020) Trophic response to ecological conditions of habitats: Evidence from trophic variability of freshwater fish. Ecology and Evolution 10, 7250-7260. 


  • Furukawa Y., Chikaraishi Y., Ohkouchi N., Ogawa, N.O., Glavin D.P., Dworkin J.P., Abe C., Nakamura T. (2019) Extraterrestrial ribose and other sugars in primitive meteorites. Proceedings of the National Academy of Sciences 116, 24440-24445.
  • Pauli j.N., Manlick P.J., Dharampal P.S., Takizawa Y., Chikaraishi Y., Niccolai L.J., Grauer J.A., Black K.L., Restrepo G.M., Perring P.L., Wilson E.C., Martin M.E., Curras M.R., Bougie T.A., Thomson K.L., Smith M.M., Steffan S.A. (2019) Quantifying niche partitioning and multichannel feeding among tree squirrels. Food Webs 21, e00124.
  • Goulden A. KE., Ohkouchi N., Freeman K.H., Chikaraishi Y., Ogawa N.O., Suga H., Chadwick O., Houlton B.Z. (2019) Strong correspondence between nitrogen isotope composition of foliage and chlorin across a rainfall gradient: implications for paleo-reconstruction of the nitrogen cycle. Biogeosciences 16, 3869-3882.
  • Steffan A.S., Dharampal P.S., N. Danforth B.N., Gaines-Day H.R., Takizawa Y., Chikaraishi Y. (2019) Omnivory in bees: Elevated trophic positions among all major bee families. American Naturalist, in press.
  • Itahashi Y., Erdal Y.S., Tekin H., Omar L., Miyake Y., Chikaraishi Y., Ohkouchi N, Yoneda M. (2019) Amino acid 15N analysis reveals change in the importance of freshwater resources between the hunter-gathere and farmer in the Neolithic upper Tigris. American Journal of Physical Anthrophology 168, 676-686.
  • Morra K.E., Chikaraishi Y., Grandhi H. James H.F., Rossman S., Wiley A.E., Raine A.F., Beck J., Ostrom P.H., (2019) Trophic decline and decadal-scale foraging segregation in three pelagic seabirds. Oecologia 189, 395-406.
  • Wyatt, A.S.J., Matsumoto R., Chikaraishi Y., Miyairi Y., Yokoyama Y., Sato K., Ohkouchi N., Nagata T. (2019) Enhancing insights into foraging specialization in the world’s largest fish using a multi-tissue, multi-isotope approach. Ecological Monographs 89 e01339.


  • Choi B., Takizawa Y., Chikaraishi Y. (2018) Compression of trophic discrimination in 15N/14N within amino acids for herbivorous gastropods. Researches in Organic Geochemistry 34, 29-35.
  • Sugahara H., Takano Y., Tachibana S., Sugawara I., Chikaraishi Y., Ogawa N.O., Ohkouchi N. Kouchi A. (2018) Molecular and isotopic compositions of nitrogen-containing organic molecules formed during UV-IR radiation of sumulated interstellar ice. Geochemical Journal 53, 5-20.
  • Chang N.-N., Lin L.-H., Tu T.-H., Jeng M.-S., Chikaraishi Y., Wang P.-L. (2018) Trophic structure and energy flow in a shallow-water hydrothermal vent: insights from a stable isotope approach. PLoS ONE 10, e0204753.
  • Takano Y., Chikaraishi Y., Imachi H, Miyairi Y., Ogawa N.O., Kaneko M., Yokoyama Y., Kruger M., Ohkouchi N, (2018) Insight into anaerobic methanotrophy from 13C/12C-amino acids and 14C/12C-ANME cells in seaflower microbial ecology. Scientific Reports 8, 14070.
  • Ishikawa N.F., Chikaraishi Y., Takano Y., Sasaki Y., Takizawa Y., Tsuchiya M., Tayasu I., Nagata T., Ohkouchi N. (2018) A new analytical method for determination of the nitrogen isotopic composition of methionine: its application to aquatic ecosystems with mixed resources. Limnology and Oceanography: Methods 16, 607-620.
  • Tsuchiya M., Chikaraishi Y., Namaki, H., Sasaki, Y., Tame A., Uematsu K., Ohkouchi N. (2018) Compound-specific isotope analysis of benthic foraminifer amino acids suggests microhabitat variability in rocky-shore environments, Ecology and Evolution 8, 8380-8395.
  • Urai A., Takahashi K., Chikaraishi Y., Fukushima K. (2018) Algal-derived 24-ethylcholesta-5,22-dien-3β-ol (stigmasterol) is frequently found in high-molecular-weight dissolved organic matter (HMW-DOM) during summer in freshwater and brackish lakes. Geochemical Journal 52, e15-e20.
  • Goto A.S., Miura K., Korenaga T., Hasegawa T., Ohkouchi N., Chikaraishi Y. (2018) Fractionation of Stable Nitrogen Isotopes (15N/14N) during Enzymatic Deamination of Glutamic Acid: Implications for Mass and Energy Transfers in the Biosphere. Geochemical Journal 52, 273-280.
  • Itahashi Y., Tsuneki A., Dougherty S.P., Chikaraishi Y., Ohkouchi N., Yoneda M. (2018) Reconstruction of Neolithic food consumption based on the δ15N values for individual amino acids at Tell el-Kerkh, northern Levant. Journal of Archaeological Science: Reports 17, 775-784.
  • Nunoura T., Chikaraishi Y., Izaki R., Suwa T., Sato T., Harada T., Mori K., Kato Y., Miyazaki M., Shimamura S., Yanagawa K., Shuto A., Ohkouchi N., Fujita N., Takaki Y., Atomi H., Takai K. (2018) A primordial and reversible TCA cycle in a facultatively chemolithoautotrophic thermophile, Science 359, 559-563.
  • Blanke C., Chikaraishi Y., Vander Zanden M.J. (2018) Historical niche partitioning and long-term trophic shifts in Laurentian Great Lakes deepwater Coregonids. Ecosphere 9, e02080.


  • Takizawa Y., Chikaraishi Y. (2017) Change in the d15N value of plant amino acids on the phenology of leaf flush and senescence. Researches in Organic Geochemistry 33, 1-6.
  • Ohkouchi N., Chikaraishi Y., Close H.G., Fry B., Larsen T., Madigan D.J., McCarthy M.D., McMahon K.W., Nagata T., Naito Y.I., Ogawa N.O., Popp B.N., Steffan S.A., Takano Y., Tayasu I., Wyatt A.S.J., Yamaguchi Y.T., Yokoyama Y. (2017) Advances in the application of amino acid nitrogen isotopic analysis in ecological and biogeochemical studies. Organic Geochemistry 113, 150-174.
  • Campbell C., Nelson D., Ogawa N.O., Chikaraishi Y., Ohkouchi N. (2017) Trophic position and dietary breadth of bats revealed by nitrogen isotopic composition of amino acids. Scientific Reports 7, 15932.
  • Drucker D., Naito Y., Péan S., Prat S., Crépin L., Chikaraishi Y., Naohiko Ohkouchi, Puaud S., Lázničková-Galetová M., Patou-Mathis M., Yanevich A., Bocherens H. (2017) Mammoth and plant in the diet of the oldest anatomically modern humans from far southeast Europe?. Scientific Reports 7, 6833.
  • Takishita K., Chikaraishi Y., Tanifuji G., Ohkouchi N., Hashimoto T., Fujikura K., Roger A.J. (2017) Microbial Eukaryotes that Lack Sterols. Journal of Eukaryotic Microbiology 64, 897-900.
  • Itahashi Y., Miyake Y., Maeda O., Kondo O., Hongo H., Neer W.V., Chikaraishi Y., Ohkouchi N., Yoneda M. (2017) Preference for fish in a Neolithic hunter-gatherer community of the upper Tigris, elucidated by amino acid δ15N analysis. Journal of Archaeological Science 82, 40-49.
  • Takishita k., Takaki Y. Chikaraishi Y, Ikuta T., Ozawa G., Yoshida T., Ohkouchi N., Fujikura K. (2017) Genomic evidence that methanotrophic endosymbionts likely provide deep-sea Bathymodiolus mussels with a sterol intermediate in cholesterol biosynthesis. Genome Biology and Evolution 9, 1148-1160.
  • Yamaguchi Y.T., Chikaraishi Y., Takano Y., Ogawa N.O., Imachi H., Yokoyama Y., Ohkouchi N. (2017) Fractionation of nitrogen isotopes during amino acid metabolism in heterotrophic and chemoautotrophic microbes across Eukarya, Bacteria, and Archaea: Effects of nitrogen sources and metabolic pathways. Organic Geochemistry 111, 101-112.
  • Ishikawa N.F., Chikaraishi Y., Ohkouchi N., Murakami A.R., Tayasu I., Togashi H., Okano J. Sakai Y., Uwata T., Kondoh M, Okuda N. (2017) Integrated trophic position decreases in more diverse communities of stream food webs. Scientific Reports 7, 2130.
  • Ostrom P.H., Wiley A.E., James H.F., Rossman S., Walker W.A., Zipkin E., Chikaraishi Y. (2017) Broad-Scale Trophic Shift in the Pelagic North Pacific Revealed by an Oceanic Seabird. Proceedings of the Royal Society B 284, 20162436.
  • Takizawa Y., Dharampal P.S., Steffan S.A., Takano Y., Naohiko N., Chikaraishi Y. (2017) Intra-trophic isotopic discrimination of 15N/14N for amino acids in autotrophs: implication for nitrogen dynamics in ecological studies. Ecology and Evolution 7, 2916-2924.
  • Sugahara H, Takano Y., Ogawa N.O., Chikaraishi Y., Ohkouchi N. (2017) Nitrogen isotopic fractionation in ammonia during adsorption on silicate surfaces. ACS Earth and Space Chemistry 1, 24-19
  • Blanke, C.M., Chikaraishi Y., Takizawa Y., Steffan S.A., Dharampal P.S., Vander Zanden, M.J. (2017) Comparing compound-specific and bulk stable nitrogen isotope trophic discrimination factors across multiple freshwater fish species and diets. Canadian Journal of Fisheries and Aquatic Sciences 74, 1291-1297.
  • Ishikawa N.F., Hayashi F., Sasaki Y., Chikaraishi Y., Ohkouchi N. (2017) Trophic discrimination factor of nitrogen isotopes within amino acids in the dobsonfly Protohermes grandis (Megaloptera: Corydalidae) larvae in a controlled feeding experiment. Ecology and Evolution 7, 1674-1679.
  • Steffan S.A., Chikaraishi Y., Dharampal P.S., Pauli J.N., Guédot C., Ohkouchi N. (2017) Unpacking brown food-webs: Animal trophic identity reflects rampant microbivory. Ecology and Evolution 7, 3532-3541.
  • Choi B., Ha S.-Y., Lee J.-S., Chikaraishi Y., Ohkouchi N., Shin K.-H. (2017) Trophic interaction among organisms in a seagrass meadow ecosystem as revealed by bulk δ13C and amino acid δ15N analyses. Limnology and Oceanography 62, 1426-1435.
  • Williams B., Thibodeau B., Chikaraishi Y., Ohkouchi N., Walnum A., Grottoli A., Colin P., (2017) Consistency in coral skeletal amino acid composition offshore of Palau in the western Pacific warm pool indicates no impact of decadal variability in nitricline depth on primary productivity. Limnology and Oceanography 62, 399-407.


  • Ohkouchi N., Shibata H., Chikaraishi Y., Nomaki H., Ogawa N.O., Nagata T., Goto T., Fujikura K., Kitazato H. (2016) A monitoring result of polychlorinated biphenyls (PCBs) in deep-sea organisms and sediments off Tohoku during 2012-2014: temporal variation and the relationship with the trophic position. Journal of Oceanography 72, 629-639.
  • Naito Y.I., Germonpré M., Chikaraishi Y., Ohkouchi N., Drucker D.G., Hobson K.A., Edwards M.A., Wißing C., Bocherens H. (2016) Evidence for herbivorous cave bears (Ursus spelaeus) in Goyet Cave, Belgium: Implications for paleodietary reconstruction of fossil bears using amino acid δ15N approaches. Journal of Quaternary Science 31, 598-606.
  • Schimmelmann A., Qi T., Coplen T.B., Brand W.A., Fong J., Meier-Augenstein W., Kemp H.F., Toman B., Ackermann A., Assonov S., Aerts-Bijma A.T., Brejcha R., Chikaraishi Y., Darwish T., Elsner M., Gehre M., Geilmann H., Gröning M., Hélie J.-F., Herrero-Martín S., Meijer H.A.J., Sauer P.E., Sessions A.L., Werner R.A. (2016) Organic Reference Materials for Hydrogen, Carbon, and Nitrogen Stable Isotope-Ratio Measurements: Caffeines, n‑Alkanes, Fatty Acid Methyl Esters, Glycines, L‑Valines, Polyethylenes, and Oils. Analytical Chemistry 88, 4294-302.
  • Naito Y.I., Drucker D.G., Chikaraishi Y., Ohkouchi N., Wißing C., Semal P., Bocherens H. (2016) Ecological niche of Neanderthals from Spy cave revealed by nitrogen isotopes of individual amino acids in collagen. Journal of Human Evolution 93, 82-90.
  • Chan Q.H.S., Chikaraishi Y., Takano Y., Ogawa N.O., Ohkouchi N. (2016) Amino acid compositions in heated carbonaceous chondrites and their compound-specific nitrogen isotopic ratios. Earth, Plantes and Space 68, 7.


  • Kruger B.R., Werne J.P., Branstrator D.K., Hrabik T.R., Chikaraishi Y., Ohkouchi N., Minor E.C. (2015) Organic Matter Transfer in Lake Superior’s Food Web: Insights from Bulk and Molecular Stable Isotope and Radiocarbon Analyses. Limnology and Oceanography 61, 149-164.
  • Naito Y.I., Bocherens H., Chikaraishi Y., Drucker D.G., Wißing C., Yoneda M., Ohkouchi N. (2015) An overview of methods used for the detection of aquatic resource consumption by humans: Compound-specific delta N-15 analysis of amino acids in archeological materials. Journal of Archaeological Science: Reports 6, 720-732.
  • Miyachi S., Mayahara T., Tsushima K., Sasada K., kohno E., Ogawa N.O., Chikaraishi Y., Ohkouchi N. (2015) Approach to determine individual trophic level and the difference on food sources of Japanese anchovy Engraulis japonicas in Sagami Bay, based on compound-specific nitrogen stable isotope analysis of amino acids. Fisheries Science 81, 1053-1062.
  • Yamanaka T., Shimamura S., Chikaraishi Y., Haga T., Fujiwara Y. (2015) Re-evolution of nutrient sources for deep-sea wood-boring bivalves using the isotopic composition of bulk C, N, S, and amino acid N. Marine ecology progress series 540, 157-165.
  • Steffan A.S., Chikaraishi Y., Currie C.R., Horn H., Gaines-Day H.R., Pauli J.N., Zalapa J., Ohkouchi N. (2015) Microbes are trophic analogs of animals: Unification of the macro- and microbiome in food web ecology. Proceedings of the National Academy of Sciences of the United States of America 112, 15119-15124.
  • Hirahara M., Chikaraishi Y., Toda T. (2015) Isotopic discrimination of 15N/14N of amino acid among the calanoid copepod Acartia steuri and its food items, eggs, and fecal pellets. Researches in Organic Geochemistry 31, 29-32.
  • Steffan S.A., Chikaraishi Y., Horton D.R., Miliczky E., Zalapa J.E., Jones V.P., Ohkouchi N. (2015) Beneficial or not? Decoding carnivore roles in plant protection. Biological Control 91, 34-41.
  • Nomaki H, Chikaraishi Y., Tsuchiya M., Toyofuku T., Suga H, Sasaki Y., Uematsu K., Tame A., Ohkouchi N. (2015) Variation in the nitrogen isotopic composition of amino acids in benthic foraminifera: implications for their adaptation to oxygen-depleted environments. Limnology and Oceanography 60, 1906-1916.
  • Kruse S., Pakhomov E.A., Hunt B.P.V., Chikaraishi Y., Ogawa N.O., Bathmann U. (2015) Uncovering the trophic relationship between Themisto gaudichaudii and Salpa thompsoni in the Antarctic Polar Frontal Zone. Marine Ecology Progress Series 529, 63-74.
  • Chikaraishi Y., Steffan S.A., Takano Y., Ohkouchi N. (2015) Diet quality influences isotopic discrimination among amino acids in an aquatic vertebrate. Ecology and Evolution 5, 2048-2059.
  • Ohkouchi N., Ogawa N.O., Chikaraishi Y., Tanaka H., Wada E. (2015) Biochemical and physiological bases for the use of carbon and nitrogen isotopes in environmental and ecological studies. Progress in Earth and Planetary Science 2, DOI 10.1186/s40645-015-0032-y.
  • Takano Y., Chikaraishi Y., Ohkouchi N. (2015) Isolation of underivatized amino acids by ion-pair high performance liquid chromatography for precise measurement of nitrogen isotopic composition of amino acids: development of comprehensive LC x GC/C/IRMS method. International Journal of Mass Spectrometry 379, 16-25.


  • Takizawa Y., Chikaraishi Y. (2014) Are baby sprouts eating the proteins in the mother sweet potato? Researches in Organic Geochemistry 30, 29-32.
  • Itahashi Y., Chikaraishi Y., Ohkouchi N., Yoneda M. (2014) Refinement of reconstructed ancient food webs based on the nitrogen isotopic compositions of amino acids from bone collagen: A case study of archaeological herbivores from Tell Ain el-Kerkh, Syria. Geochemical Journal 48, e15-e19.
  • Maki K., Ohkouchi N., Chikaraishi Y., Fukuda H., Miyajima T., Nagata T. (2014) Influence of nitrogen substrates and substrate C:N ratios on the nitrogen isotopic composition of amino acids from the marine bacterium Vibrio harveyi. Geochimica et Cosmochimica Acta 140, 521-530.
  • Nomaki H., Chikaraishi Y., Tsuchiya M., Toyofuku T., Ohkouchi N., Uematsu K., Tame A., Kitazato H. (2014) Nitrate uptake by foraminifera and use in conjunction with endobionts under anoxic conditions. Limnology and Oceanography 59, 1879-1888.
  • Chikaraishi Y., Steffan S.A., Ogawa N.O., Ishikawa F.I., Sasaki Y., Tsuchiya M., Ohkouchi N. (2014) High-resolution food webs based on nitrogen isotopic composition of amino acids. Ecology and Evolution 4, 2423-2449.
  • Kaneko M., Takano Y., Chikaraishi Y., Ogawa, N.O., Asakawa S., Watanabe T., Shima S., Krüger M., Matsushita M., Kimura H., Ohokouchi N. (2014) Quantitative analysis of coenzyme F430 in environmental samples: a new diagnostic tool for methanogenesis and anaerobic methane oxidation. Analytical Chemistry 86, 363-3638.


  • Aoyagi K., Goto A.S., Fujino T., Korenaga T., Chikaraishi Y. (2013) Deuterium depletion in the fatty acids from beef. Researches in Organic Geochemistry 29, 65-69.
  • Steffan S.A., Chikaraishi Y., Horton D.R., Ohkouchi N., Singleton M.E., Miliczky E., Hogg D.B., Jones V.P. (2013) Trophic hierarchies illuminated via amino acid isotopic analysis. PLoS ONE 8, e76152.
  • Naito I.Y., Chikaraishi Y., Ohkouchi N., Drucker D.G., Bocherens H. (2013) Nitrogen isotopic composition of collagen amino acids as an indicator of aquatic resource consumption: insights from Mesolithic and Epipalaeolithic archaeological sites in France, World Archaeology, 45, 338-359.
  • Ohkouchi N., Tsuda R., Chikaraishi Y., Tanabe K. (2013) A preliminary estimate of the trophic position of the deep-water ram’s horn squid Spirula spirula based on the nitrogen isotopic composition of amino acids. Marine Biology 160, 773-779.
  • Naito I.Y., Chikaraishi Y., Ohkouchi N., Yoneda M. (2013) Evaluation of carnivory in inland Jomon hunter-gatherers based on nitrogen isotopic compositions of individual amino acids in bone collagen. Journal of Archaeological Science 40, 2913-2923.


  • Takahashi Y., Sasaki Y., Chikaraishi Y., Tsuchiya M., Watanabe H., Asahida T., Maruyama T., Fujikura K. (2012) Does the symbiotic scale-worm feed on the host mussel in deep-sea vent fields? Researches in Organic Geochemistry 28, 23-26.
  • Aoyagi K., Yamanaka A., Goto A.S., Fujino T., Korenaga T., Chikaraishi Y. (2012) Methyl and ethyl chloroformate derivatizations for compound-specific stable isotope analysis of fatty acids-II. Researches in Organic Geochemistry 28, 27-30.
  • Miller M.J., Chikaraishi Y., Ogawa N.O., Yamada Y., Tsukamoto K., Ohkouchi N. (2012) A low trophic position of Japanese eel larvae indicates feeding on marine snow. Biology Letters 9, DOI: 10.1098/rsbl.2012.0826.
  • Chikraiashi Y., Kaneko M., Ohkouchi N. (2012) Stable hydrogen and carbon isotopic compositions of long-chain (C21–C33) n-alkanes and n-alkenes in insects. Geochimica et Cosmochimica Acta 95, 53-62. Maeda T., Hirose E., Chikaraishi Y., Takishita K., Yoshida T., Verbruggen H., Tanaka J., Shimamura S., Takai Y., Tsuchiya M., Iwai K., Maruyama T. (2012) Algivore or phototroph? Plakobranchus ocellatus (Gastropoda) continuously acquires kleptoplasts and nutrition from multiple algal species in nature. PLoS ONE 7, e42024.
  • Ogawa N.O., Chikaraishi Y., Ohkouchi N. (2012) Trophic position estimates of formalin-fixed samples with nitrogen isotopic compositions of amino acids: an application to gobiid fish (Isaza) in Lake Biwa, Japan. Ecological Research 28, 697-702.
  • Takishita K., Chikaraishi Y., Leger M.M., Kim E., Yabuki A., Ohkouchi N., Roger A.J. (2012) Lateral transfer of tetrahymenol-synthesizing genes has allowed multiple diverse eukaryote lineages to independently adapt to environments without oxygen. Biology Direct 7:5.
  • Sachse D., Billault I, Bowen G.J., Chikaraishi Y., Dawson T.D., Feakins S.J., Freeman K.H., Magill C.R., McInerney F.A., van der Meer M.T.J., Polissar P., Robins R.J., Sachs J.P., Schmidt H.-L., Sessions A.L., White J.W.C., West J.B., Kahmen A. (2012) Molecular paleohydrology: interpreting the hydrogen-isotopic composition of lipid biomarkers from photosynthesizing organisms. Annual Review of Earth and Planetary Sciences 40, 221-249.


  • Strable M.S., Tschanz C.L., Varamini B., Chikaraishi Y., Ohkouchi N., Brenna J.T. (2011) Mammalian DNA δ15N exhibits 40% intramolecular variation and is unresponsive to dietary protein level. Rapid communications in Mass Spectrometry 25, 3555-3563.
  • Goto A.S., Korenaga T., Chikaraishi Y. (2011) Methyl (MCF) and ethyl chloroformate (ECF) derivatizations for compound-specific stable isotope analysis (CSIA) of fatty acids. Researches in Organic Geochemistry 27, 91-95.
  • Chikaraishi Y., Ogawa N.O., Doi H., Ohkouchi N. (2011) 15N/14N ratios of amino acids as a tool for studying terrestrial food webs: a case study of terrestrial insects (bees, wasps, and hornets). Ecological Research 26, 835-844.
  • Zhou Y., Grice K., Chikaraishi Y., Stuart-Williams H., Farquhar G.D., Ohkouchi, N. (2011) Temperature effect on leaf water deuterium enrichment and isotopic fractionation during leaf lipid biosynthesis: Results from controlled growth of C3 and C4 land plants. Phytochemistry 72, 207-213.


  • Sonoda K., Takahashi M., Chikaraishi Y., Yammamoto, S. (2010) Compound-specific stable carbon isotope analysis of lignin phenols by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Researches in Organic Geochemistry 26, 115-122.
  • Akamatsu F., Yamamoto M., Chikaraishi Y., Toda H. (2010) Evaluation of algal contribution to aquatic insects based on 13C/12C and C/N ratios. Researches in Organic Geochemistry, Researches in Organic Geochemistry 26, 107-114.
  • Takano Y., Chikaraishi Y., Ogawa N.O., Nomaki H., Morono Y., Inagaki F., Kitazato H., Hinrichs K.-U., Ohkouchi, N. (2010) Sedimentary membrane lipids recycled by deep-sea benthic archaea. Nature Geosciences 3, 858-861.
  • Tyler J., Kashiyama Y., Ohkouchi N., Ogawa N.O., Yokoyama Y., Chikaraishi Y., Staff R.A., Ikehara M., Bronk Ramsey C., Bryant C., Brock F., Gotanda K., Haraguchi T., Yonenobu H., Nakagawa, T. (2010) Chlorin specific carbon and nitrogen isotopes track aquatic change over the last deglaciation in Lake Suigetsu, Japan. Geochemistry Geophysics Geosystems 11, Q09010, doi:10.1029/2010GC003186.
  • Takano Y., Kashiyama Y., Ogawa O.N., Chikaraishi Y., Ohkouchi N. (2010) Isolation and desalting with cation-exchange chromatography for compound-specific nitrogen isotope analysis of amino acids. Rapid Communications in Mass Spectrometry 24, 2317-2323.
  • Naito Y., Chikaraishi Y., Ohkouchi N., Mukai H., Shibata Y., Honch N.V., Dodo Y., Ishida H., Amano T., Ono H., Yoneda, M. (2010) Dietary reconstruction of the Okhotsk Culture of Hokkaido, Japan, based on nitrogen isotopic composition of amino acids: implication for the correction of radiocarbon marine reservoir effects on human bones. Radiocarbon 52, 671-681.
  • Naito Y., Honch N., Chikaraishi Y., Ohkouchi N., Yoneda, M. (2010) Reconstruction of ancient human diet based on nitrogen isotopic ratios of individual amino acids: a novel method for evaluating marine protein consumption. American Journal of Physical Anthropolology 143, 31-40.


  • Chikaraishi Y., Ogawa N.O., Kashiyama Y., Takano Y., Suga H., Tomitani A., Miyashita H., Ohkouchi N. (2009) Determination of aquatic food-web structure based on compound-specific nitrogen isotopic composition of amino acids. Limnology and Oceanography: Methods 7, 740-750.
  • Chikaraishi Y., Tanaka R., Tanaka A., Ohkouchi N. (2009) Fractionation of hydrogen isotopes in phytol biosynthesis. Organic Geochemistry, 40, 569-573.
  • Takano Y., Chikaraishi Y., Ogawa N.O., Kitazato H., Ohkouchi N. (2009) Compound-specific nitrogen isotope analysis of D-alanine, L-alanine, and valine: application of diastereomer separation to δ15N and microbial peptidoglycan studies. Analytical Chemistry 81, 394-399.
  • Nomaki H., Ohkouchi N., Heinz P., Suga H., Chikaraishi Y., Ogawa N.O., Matsumoto K., Kitazato H. (2009) Degradation of algal lipids by deep-sea benthic foraminifera: An in situ tracer experiment. Deep-Sea Research I 56, 1488-1503.


  • Chikaraishi Y., Kashiyama Y., Ogawa, N.O., Kitazato H., Satoh M., Nomoto S., Ohkouchi N. (2008) A compound-specific isotope method for measuring the stable nitrogen isotopic composition of tetrapyrroles. Organic Geochemistry 39, 510-520.
  • Kashiyama Y., Miyashita M, Ohkubo S., Ogawa N.O., Chikaraishi Y., Takano Y., Suga H., Toyofuku T., Nomaki H., Kitazato H., Nagata T., Ohkouchi N. (2008) Evidence of Global Chlorophyll d. Science 321, 658.
  • Ohkouchi N., Nakajima Y., Ogawa N.O., Chikaraishi Y., Suga H., Sakai S., and Kitazato H. (2008) Carbon isotopic composition of the tetrapyrrole nucleus in chloropigments from a saline meromictic lake: A mechanistic view for interpreting the isotopic signature of alkyl porphyrins in geological samples. Organic Geochemistry 39, 521-531.
  • Nakashita R., Suzuki Y., Akamatsu F., Iizumi Y., Korenaga T., Chikaraishi Y. (2008) Stable carbon, nitrogen, and oxygen isotope analysis as a potential tool for verifying geographical origin of beef. Analytica Chimica Acta 617, 148-152.
  • Jenkins R.G., Hikida Y., Chikaraishi Y., Ohkouchi N., Tanabe K. (2008) Microbially induced formation of ooid-like coated grains in the Late Cretaceous methane-seep deposits of the Nakagawa area, Hokkaido, northern Japan. Island Arc 17, 261-269.
  • Suzuki Y, Chikaraishi Y., Ogawa N.O., Ohkouchi N., Korenaga T. (2008) Geographical origin of polished rice based on multiple element and stable isotope analyses. Food Chemistry 109, 470-475.


  • Chikaraishi Y., Kashiyama Y., Ogawa N.O., Kitazato H., Ohkouchi N.O. (2007) Biosynthetic and metabolic controls of nitrogen isotopic composition of amino acids in marine macroalgae and gastropods: implications for aquatic food web studies. Marine Ecology Progress Series 342, 85-90.
  • Chikaraishi Y., Matsumoto K., Kitazato H., Ohkouchi N. (2007) Sources and transformation process of pheopigments: Carbon and hydrogen isotopic evidence from Lake Haruna, Japan. Organic Geochemisyry 38, 985-1001.
  • Chikaraishi Y., Naraoka H. (2007) δ13C and δD relationships among three n-alkyl compound classes (n-alkanoic acid, n-alkane and n-alkanol) of terrestrial higher plants. Organic Geochemistry 38, 198-215.


  • Chikaraishi Y., Naraoka H. (2006) Carbon and hydrogen isotope variation of plant biomarker in a plant-soil-system. Chemical Geology 231, 190-202
  • Chikaraishi Y. (2006) Carbon and hydrogen isotopic composition of sterols in natural marine brown and red macroalgae, and in associated shellfish. Organic Geochemistry 37, 428-436.
  • Suzuki Y., Korenaga T., Chikaraishi Y. (2006) A novel method to identify illegal diesel fuel, II: the use of [1-D] n-alkane with stable hydrogen isotope analysis. Chemistry Letters 35, 532-533.
  • Rommerskirchen F., Plader A., Eglinton G., Chikaraishi Y., Rulkötter J. (2006) Chemotaxonomic significance of distribution and stable carbon isotopic composition of ling-chain alkanes and alkan-1-ols in C4 grass waxes. Organic Geochemistry 37, 1303-1332.
  • Suzuki Y., Ishioka S., Korenaga T., Chikaraishi Y. (2006) A novel method to identify illegal diesel fuel, I: the use of adamantan or [1, 2-D2] n-tetradecane as a chemical marker. Environmental Science 13, 207-212.


  • Chikaraishi Y., Yamada Y., Naraoka H. (2005) Carbon and hydrogen isotope compositions of sterols from riverine and marine sediments. Limnology and Oceanography 50, 1763-1770.
  • Chikaraishi Y., Matsumoto K., Ogawa N.O., Suga H., Kitazato H., Ohkouchi N. (2005) Hydrogen, carbon and nitrogen isotopic fractionations during chlorophyll biosynthesis in C3 higher plants. Phytochemistry 66, 911-920.
  • Chikaraishi Y., Naraoka H. (2005) δ13C and δD identification of sources of lipid biomarkers in sediments of Lake Haruna (Japan). Geochimica et Cosumochimica Acta 69, 3285-3297.


  • Chikaraishi Y., Suzuki Y., and Naraoka H. (2004) Hydrogen isotopic fractionations during desaturation and elongation associated with polyunsaturated fatty acid biosynthesis in marine macroalgae. Phytochemistry 65, 2293-2300.
  • Chikaraishi Y., Naraoka H., and Poulson S.R. (2004) Hydrogen and carbon isotopic fractionations of lipid biosynthesis among terrestrial (C3, C4 and CAM) and aquatic plants. Phytochemistry 65, 1369-1381.
  • Chikaraishi Y., Naraoka H., and Poulson S.R. (2004) Carbon and hydrogen isotopic fractionation during lipid biosynthesis in a higher plant (Cryptomeria japonica). Phytochemistry 65, 323-330.


  • Chikaraishi Y., Naraoka H. (2003) Compound-specific δD-δ13C analyses of n-alkanes extracted from terrestrial and aquatic plants. Phytochemistry 63, 361-371.


  • Chikaraishi Y., Naraoka H. (2001) Organic hydrogen-carbon isotope signatures of terrestrial higher plants during biosynthesis for distinctive photosynthetic pathways. Geochemical Journal 35, 451-458.