Japan Geoscience Union Meeting 2019

Presentation information

[E] Oral

B (Biogeosciences ) » B-BG Biogeosciences & Geosphere-Biosphere Interactions

[B-BG01] Elemental cycling in terrestrial and coastal ecosystems- Carbon and Nitrogen perspectives

Mon. May 27, 2019 3:30 PM - 5:00 PM 201A (2F)

convener:Punyasloke Bhadury(Indian Institute of Science Education and Research Kolkata), Chairperson:Punyasloke Bhadury(Indian Institute of Science Education and Research Kolkata)

4:45 PM - 5:00 PM

[BBG01-05] Spatial and vertical variations of carbon and nitrogen isotopes of larch forest and NDVI in Eastern Siberia

*Aleksandr Nogovitcyn1, Atsuko Sugimoto2, Ruslan Shakhmatov1, Tomoki Morozumi1, Shunsuke Tei2, Yumiko Miyamoto2, Trofim Maximov3,4 (1.Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, Japan, 2.Arctic Research Center, Hokkaido University, Sapporo, Hokkaido, Japan, 3.Institute for Biological Problems of Cryolithozone, Siberian Blanch of Russian Academy of Sciences, Yakutsk, Yakutia, Russia, 4.International Center for Biogeoscience Educational and Scientific Trainings (BEST), North-Eastern Federal University, Yakutsk, Yakutia, Russia)

Keywords:taiga (boreal) forest, NDVI, carbon isotope, nitrogen isotope

Under a global climate change, taiga forest ecosystem is expected to change. Tree ring data obtained at northeast Siberian Taiga indicated tree growth decrease during warm climate (Tei et al., 2014), consequently primary production may decrease in the future. As tools for monitoring ecosystem changes, stable isotope of carbon δ13C and nitrogen δ15N are widely applied in ecological research. The δ13C is a common proxy for water use efficiency in plants, and the δ15N is for nitrogen availability that is important because boreal forest on permafrost is usually poor in the nitrogen (Popova et al., 2013).

Observations were conducted at Spasskaya Pad forest station (62°25’ N, 129°62’ E) near Yakutsk, Russia. The forest is usually dry, but after the extreme wet event in 2007, wet sites were distributed in the forest. Transect (60m x 510m) with 30m x 30m plots, in total 33, was set including dry sites and wet sites, to obtain needle samples from 104 trees at the height of 5-6 m were obtained in order to investigate spatial variations in δ13C, δ15N, and N contents. These spatial variations were compared with satellite-derived Normalized difference vegetation index (NDVI) using Landsat images with the resolution of 30 m. Lower NDVI and lower foliar N content were observed at wet sites than those at dry sites. A high δ13C and high δ15N were also observed at a wet site. After extreme wet event happened, ecosystem (and N availability) changes and NDVI also changes. We also obtained the needles from two trees at different heights in a jungle gym to investigate the vertical variations in δ13C and δ15N. There were large differences in δ13C, δ15N and N contents vertically.

Tei, S., A. Sugimoto, H. Yonenobu, T. Ohta, T. C. Maximov. Growth and physiological responses of larch trees to climate changes deduced from tree-ring widths and δ13C at two forest sites in eastern Siberia. Polar Science, 8, 183-195, doi:10.1016/j.polar.2013.12.002, 2014

Popova A.S., N. Tokuchi, N. Ohte, M.U. Ueda, K. Osaka, T.Ch. Maximov and A. Sugimoto. Nitrogen availability in the taiga forest ecosystem of northeastern Siberia. Soil Science and Plant Nutrition, 59, 427-441, doi:10.1080/00380768.2013.772495, 2013