Japan Geoscience Union Meeting 2015

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Symbol B (Biogeosciences) » B-GM Geomicrobiology

[B-GM22] Microbial ecology in earth and planetary sciences

Tue. May 26, 2015 9:00 AM - 10:45 AM 105 (1F)

Convener:*Michinari Sunamura(University of Tokyo Dept. of Earth & Planetary Science), Ken Takai(Extremobiosphere Research Center, Japan Agency for Marine-Earth Science & Technology), Keisuke Koba(Tokyo University of Agriculture and Technology), Natsuko Hamamura(Ehime University), Chair:Takuro Nunoura(Research and Development Center for Marine Biosciences, Japan Agency for Marine-Earth Science & Technology (JAMSTEC)), Michinari Sunamura(University of Tokyo)

9:45 AM - 10:00 AM

[BGM22-04] Isotopic fractionations during nitrogen removal in the activated sludge

*Syoutoku KOTAJIMA1, Keisuke KOBA1, Daisuke IKEDA2, Akihiko TERADA2, Kazuichi ISAKA3 (1.Tokyo University of Agriculture and Technology, 2.Tokyo University of Agriculture and Technology, 3.Hitachi, Ltd)

Anammox is considered to be an important nitrogen removal pathway in the ecosystem. However, it is still unknown how much the anammox can contribute to the total nitrogen loss in the ecosystem. Natural abundance of stable isotopes can be a promising tool to investigate the relative contribution of anammox and denitrification in the intact ecosystem, although the isotopic fractionation factors during anammox which are necessary to interpret isotopic signatures are not fully known. Here we reported nitrogen and oxygen isotopic fractionation factors during anammox occuring in the activated sludge. We incubated the sludge anaerobically to trace the changes in concentrations and isotopic signatures of ammonium, nitrite and nitrate during the anammox process. We found the large isotopic fractionations for ammonium oxidation and nitrite reduction by anammox. In addition, the inverse isotopic fractionation during nitrite oxidation to nitrate was observed. We will discuss these factors with comparison of the latest study on anammox isotopic systematics (Brunner et al. 2013) in the presentation.