| Co-Investigator(Kenkyū-buntansha) |
SATO Takaharu Hiroshima University, Faculty of Integrated Arts and Sciences, Associate Professor, 総合科学部, 助教授 (90196246)
KITAGAWA Ryuji Hiroshima University, Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (70112167)
ONODERA Shin-ichi Hiroshima University, Faculty of Integrated Arts and Sciences, Associate Professor, 総合科学部, 助教授 (50304366)
OHO Yukimasa Hiroshima University, Faculty of Integrated Arts and Sciences, Professor, 総合科学部, 教授 (80152560)
KAIHOTSU Ichiro Hiroshima University, Faculty of Integrated Arts and Sciences, Professor, 総合科学部, 教授 (60160959)
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| Research Abstract |
For sustainable use of Seto Inland Sea and coastal catchments, we confirmed natural mass cycle flux and soil degradation rate and evaluate the variation of mass cycle with environmental change, such as acid rain, global warming, forest fire, artificial impact.
Our conclusions are summarize as follows,
1. We quantified various flux in mass cycle of catchments evapotranspiration rate, infiltration rate, river discharge, groundwater flow, vegetation growing rate, weathering rate, erosion rate. Consequently, soil degradation trend was confirmed in forest fire catchments for initial two years. Erosion rate in forest fire catchments became more than 30 times of that in forest.
2. We conducted the scale up the weathering process and rate in micro view and short term scales. The weathering rate in micro scale was higher than that in catchment scale. This was solved by heterogeneity of weathering process such as micro sheeting joints and fissure, thermal water effect, groundwater slow in long term. Furthermore, both of biochemical process and rainfall as the unstable condition had significant role on that.
3. We evaluated the transport of anthropogenic input mass ; trace metal of atmosphere fall and nitrate of agricultural input and living waste. Trace metal was released from soil with acidification and discharged in dissolved form in the source area. On the other hand, it was transported with suspension in down stream due to adsorption. Nitrate discharged through the river to sea. But the content decreased by some purification process such as denitrification in groundwater and river bed.
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