权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

The dynamics of dissolved organic substances in forest catchments and the process of threr export in streams, Hokkaido, Japan.

日本北海道森林流域中溶解有机物质的动态以及溪流中溶解有机物质的输出过程。

基本信息

批准号：
06454085
负责人：
FUJIWARA Koichiro
金额：
$ 0.51万
依托单位：
Yamagata University (1995)Hokkaido University (1994)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

The monitoring of water soluble materials was carried out to clarify the dynamics of dissolved organic substances in the catchments covered by the boreal forests of Hokkaido, Japan. The results obtained were as follows :1) A large amount of organic substances was included in throughfall, stem flow and leachate from the O horizon of the catchments investigated. Most of organic substances running into the catchments, however, was immidiately adsorbed in the surface of the soil, so that their concentration in the strem water were very low.2) In japan, it is generally considered that clear water runs in the catchment covered by forests.In case of serpentine rock catchment covered by coniferous forests (Picea glehnii), however, the value of E260 (the absorvance of 260nm), the index of humic substanses in stream water, was higher than the criterion of World Health Organization (WHO). This result indicates that the pretreatment wasnecessary to remove organics when such a stream water was used as a source of drinkable water.3) In rain events, considerable amounts of dissolved organic substances was exported to the stream of the catchments. A thick O horizon consist of the litter from coniferous trees was the source of dissolved organic substances. Macro-molecular organic acids were dominant anion species of the leachate from the O horizon of forest catcments.4) llydrograph separation based on total organic carbon (TOC) indicated that about 40% of runoff in a rain evet was a direct flow. As the concentration of TOC showed pronounced decrease in the leachate from B horizon, the direct flow was considered to run through O and A horizons and into the stream. The low permeability of the soil in the catchments seems to concern with the appearance of direct flow. These results suggest that the pollution of stream water by organic substances from forests depends on the condition of soil formation factors such as climate, surface geology, vegetation.

对水溶性物质进行监测是为了阐明日本北海道北方森林覆盖的流域中溶解有机物质的动态。所得结果如下：1）调查流域O层的径流、茎流和渗滤液中含有大量有机物质。然而，流入流域的大部分有机物质立即被土壤表面吸附，因此它们在流水中的浓度非常低。2）在日本，通常认为森林覆盖的流域是清水。但是，在针叶林（云杉）覆盖的蛇纹岩流域中，E260值（260nm的吸光度）的指数为溪水中腐殖质含量高于世界卫生组织（WHO）标准。这一结果表明，当这种溪流水作为饮用水源时，有必要进行预处理以去除有机物。3）在降雨过程中，大量溶解的有机物质被排放到集水区的溪流中。由针叶树的枯枝落叶组成的厚厚的 O 地平线是溶解有机物质的来源。大分子有机酸是森林流域O层渗滤液的主要阴离子种类。4)基于总有机碳(TOC)的水滴仪分离表明，雨季径流中约40%为直流流。由于 B 层渗滤液中 TOC 浓度显着下降，因此考虑直接流过 O 层和 A 层并进入河流。流域土壤的低渗透性似乎与直流的出现有关。这些结果表明，森林有机物质对溪流水的污染取决于气候、地表地质、植被等土壤形成因素的状况。