Abstracts for the 5th International GAME Conf.

3-5 October 2001

Aichi Trade Center

Nagoya Japan

Observation on water isotopes in eastern Siberia for water cycle study

Atsuko SUGIMOTO (1), Daisuke NAITO (1), Atusi NUMAGUTI (3), Kimpei ICHIYANAGI (3), Naoyuki KURITA (3), Yoshiyuki ISHII (6)

Oxygen and hydrogen isotope ratios of precipitation, soil water, sap water of plants, river, surface water, and atmospheric water vapor were observed in Yakutsk, Russia. Precipitation was also taken at Tiksi. Observations of various water isotopes showed water movements as follows. Isotopic composition of precipitation characteristically changed during spring from low delta-value (winter) to high delta-value (summer). This may be caused by the change in the isotopic composition of water vapor. During summer, the relationship between hydrogen and oxygen isotope ratios was also different from that in winter. So-called d value was about 10 during winter, while, d value was low in summer precipitation. Recycling of water from the surface through plants may contribute the isotopic composition of atmospheric water vapor. Soil water stored in permafrost has an important role for water cycle in this area. Stable isotope ratio of sap water in plants were different between wet summer and dry summer. Sap water delt-values were high during dry summer, and low during drought. This result indicated that rain water was used by plants when plants received enough summer rain, while melt water of ice in the soil was taken up by plants during drought. Fall precipitation may contribute the soil moisture in spring. During a period of snow thawing, a part of melt water with low delta-value percolated into the soil probably down to 30 cm. When the amount of summer rainfall was larger than that required by plants for transpiration, rainwater was stored in the soil until next summer.

Submittal Information

Name : Date :
    Atsuko SUGIMOTO
    31-May-01-13:05:06
Organization : Theme :
    Center for Ecological Research, Kyoto University
    Theme 1
Address : Presentation :
    Kamitanakami Hiranocho, Otsu 520-2113
    Poster or oral
Country : Abstract ID :
    Japan
    T1AS31May01130506
Phone : Fax :
    +81-77-549-8258
    +81-77-549-8201
E-mail :
    atsukos@ecology.kyoto-u.ac.jp