Memo of IsoEcol2016

Weiping MEI,2016/04/18

The 10^th international conference on the applications of Stable Isotopes to Ecological Studies (abbr. IsoEcol2016) has been held from 3^rd to 8^th April 2016 in the University of Tokyo. Too much wonderful presentations including oral and poster presentations impressed me deeply. And now I would like to outline some of them as below.

Firstly, the opening presentation was held by prof. Eitaro Wada. He picked out 3 majorprogresses which indicated by 3 empirical equations in stable isotopeecological studies of recent several decades. Equation 1 is about 3.4 ‰ of bulkδ¹⁵N enrich per trophic level (Wada, 1987).Equation 2 is about 7.6‰ of amino acid compound-specific stable isotopeanalysis (AA-CSIA) δ¹⁵N_Glu-Phe (Chikaraishi et al,2009). Equation 3 is about a new aspect of food-chain stable isotope analysis(SIA) with ANCOVA method (Wada et al, 2013; Aita et al, 2011).

Secondly, the presentation held by keynote speaker Yoshito Chikaraishi. He has mainlyexplained the empirical equation: TP = [(δ¹⁵N_Tr -δ¹⁵N_Src +β) / TDF] + 1. “Tr” and “Src” denote trophic and source amino acids (mostcommonly represented by glutamic acid and phenylalanine), β denotes the isotopic difference between trophic and source aminoacide in primary producers (i.e. -3.4‰ and +8.4‰ for aquatic and terrestrialplants). Meanwhile, he also pointed out that the validity of both β and TDF values should be strictlyconsidered for specific object of study.

Thirdly, presentation of Kelton McMahon. His study is based on the AA-CSIA study of Chikaraishi.The different part was that McMahon discussed about the TDF validity andsuggested multi-TDF equations for food web study. Specifically, urea/ uric-acidproducing consumers exhibit significantly lower TDF_Glu-Phe thanammonia-producing counterparts. The above similar research has alreadypublished by Kelton W. McMahon et al, 2015.

Finally, a new interest aspect was presented by Christina J Bradley. Her study showedthat Amino acid δ¹³C revealed clear evidence of amino acidsynthesis and brings into question the true nature of the “source” amino acid.Maybe this will be the hot-pot in the future stable isotope ecological studies.

In a word, if possible, try our best to attend more internationalsymposiums to broaden our horizons and do more better researches.

Appendix

EitaroWada, Japan Agencyfor Marine-Earth Science and Technology (JAMSTEC), wadaei@jamstec.go.jp; Emeritus, Kyoto University,eitaro1939@yahoo.co.jp

YoshitoChikaraishi, JAMSTEC, ychikaraishi@jamstec.go.jp

KeltonMcMahon, University ofCalifornia, Santa Cruz, kemcmaho@ucsc.edu

ChristinaJ Bradley, University ofCalifornia Merced, cbradley2@ucmerced.edu