Evaluation of effects of environmental degradation on natural mass cycles

为了濑户内海和沿海集水区的可持续利用，确定了自然质量循环通量和土壤退化率，并评价了质量循环随酸雨、全球变暖、森林火灾、人为影响等环境变化的变化规律。我们的结论总结如下：1。我们量化了流域物质循环中的各种通量：蒸散速率、入渗速率、河流流量、地下水流量、植被生长速率、风化速率、侵蚀速率。结果表明，前2年森林火灾流域土壤有退化趋势。森林火灾流域的侵蚀速率是森林侵蚀速率的30倍以上。我们在微观和短期尺度上对风化过程和速率进行了放大。微尺度的风化速率大于流域尺度的风化速率。这主要是由于风化过程的非均质性，如微片状节理和裂隙、热水效应、地下水长期缓慢等。生化过程和降雨作为不稳定条件对其均有显著影响。我们评估了人为输入质量的输运；大气中的微量金属和农业投入品及生活垃圾中的硝酸盐。土壤中微量金属随着酸化而释放，并以溶解形式在源区排放。另一方面，由于吸附作用，它随悬浮液向下游输送。硝酸盐通过河流排入大海。但由于地下水和河床的反硝化等净化过程，其含量有所下降。

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.