Japan Geoscience Union Meeting 2014

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Oral

Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS21_28PM1] Biogeochemistry

Mon. Apr 28, 2014 2:15 PM - 4:00 PM 511 (5F)

Convener:*Muneoki Yoh(Tokyo University of Agriculture and Technology), Hideaki Shibata(Field Science Center fot Northern Biosphere, Hokkaido University), Naohiko Ohkouchi(Japan Agency for Marine-Earth Science and Technology), Youhei Yamashita(Faculty of Environmental Earth Science, Hokkaido University), Chair:Ichiro Tayasu(Center for Ecological Research, Kyoto University), Tomoya Iwata(Faculty of Life and Environmental Sciences, University of Yamanashi), Rota Wagai(National Institute for Agro-Environmental Sciences, Carbon & Nutrient Cycling Division), Kazuya Nishina(National Institute for Enviromental Studies)

2:15 PM - 2:30 PM

[MIS21-12] Isotopic composition of chlorophylls as a new indicator of energy flow in stream ecosystems

*Naoto F. ISHIKAWA1, Hisami SUGA1, Nanako O. OGAWA1, Naohiko OHKOUCHI1 (1.JAMSTEC)

Keywords:periphyton, photosynthetic pigments, biomarker, HPLC, stable isotopes

In most freshwater (e.g., stream) ecosystems, periphytic algae attached to a substrate (periphyton) play an important role as benthic primary producer. However, the energy flow, which is transferred from periphyton to animal consumers through trophic pathways, has not yet been adequately assessed because few studies have traced algal signatures from periphyton matrix to food webs. Here we present a new application of the isotopic composition of chlorophylls in periphyton to the tracer of in situ primary production. Chlorophylls can be used as a biomarker of photosynthetic autotrophs, including periphytic algae. We purified chlorophylls from periphyton matrix using a high performance liquid chromatograph (HPLC), and measured carbon and nitrogen stable isotope ratios of chlorophylls, pheophytins, the bulk of periphyton, and algal grazing specialists (e.g., Epeorus latifolium: mayfly larva) using an elemental analyzer coupled with an isotope ratio mass spectrometer (EA/IRMS). We will compare the results with traditional isotope maps, and discuss the potential of the isotopic composition of chlorophylls in aquatic food web studies.