Study on evolution of hydrobiogeochemistry with forest succession in humid temperate region

湿温带森林演替的水生生物地球化学演化研究

基本信息

批准号：
10660146
负责人：
OHTE Nobuhito
金额：
$ 2.18万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

In order to examine the various impacts of the forest growth on the acid buffering processes, hydrochemical observations were carried out in three different temperate catchments, each shares the same granitic bedrock , but having a forest different in growth conditions and soil depth. Hydrological processes in those watersheds were classified as; (1) the throughfall process, (2) soil infiltration process, (surface and subsurface soil layer infiltration sub-process, and the saturated groundwater transfer sub-process) and (3) the stream runoff process. The spatial distribution of pH, proton fluxes, and the changes of the proton producing and consuming processes were clarified. Specifically observed as changes accompanied by the vegetation growth were; (1) the decomposition of organic matters generated protons and (2) in addition to the chemical weathering , the cation exchange process started to consume protons in surface soil layer. (3) as a result, the proton production was relatively … More greater than consumption the surface soil layer, and some of the protons left unconsumed were transferred down to the subsurface soil layer and consumed. Specifically observed changes relating to soil depth were ; (1) pCOィイD22ィエD2 level at the groundwater is increased, as the soil layer is thicker. (2) As a result, pH after degassing is increased as the soil depth increased. Second, to quantify the impacts of forest vegetation on the acid buffering processes, hydrochemical observation data for two separate years were used to calculate the proton budgets in three small catchments, each consisting of the same granitic bedrock, but differing in vegetation development conditions. The increase in biological activity in the forested catchments, increased the net proton production by mineralization of organic matters and N transformation. In the forested catchments, the increase in transpiration reduced stream runoff. As a result, proton production by the dissociation of COィイD22ィエD2 decreased. When the estimated value for the cation uptake by vegetation was included in the proton budget, forest development increased the sum of these net proton productions by 2.3 to 4.0 times that of bare catchments. However, more than 96% of these proton productions were consumed by weathering and cation exchange within the catchments. It became apparent that the sum of these net proton productions by atmospheric input, N transformation, assimilation of cations, and dissociation of COィイD22ィエD2 is strongly affected by the amount of annual precipitation and annual runoff. The variance of proton production due to the fluctuation of annual precipitation almost equals the range of the increase in proton production by forest growth. Less

为了检查森林生长对酸性缓冲过程的各种影响，在三个不同的温度集水区中进行了水化学观测，每种观察结果都具有相同的花岗岩基岩，但在生长条件和土壤深度上具有不同的森林。这些流域中的水文过程被归类为；（1）贯穿过程，（2）土壤渗透过程，（表面和地下土壤层浸润子过程以及饱和的地下水转移子过程）和（3）河流径流过程。阐明了pH，质子通量的空间分布以及质子产生和消耗过程的变化。特别观察到伴随着植被生长的变化；（1）有机物的分解产生了质子，（2）除了化学风化外，阳离子交换过程还开始在表面土壤层中食用质子。（3）结果，质子的产生相对……不仅是消耗的表面土壤层，而剩余的一些质子不包括在地下土壤层并消耗。特定观察到与土壤深度有关的变化是；（1）土壤层较厚，地下水的PCOI D22水平增加。（2）结果，随着土壤深度的增加，脱气后的pH值增加。其次，为了量化森林植被对酸性缓冲过程的影响，使用了两年的水化学观察数据来计算三个小流域的质子预算，每个集水区都由相同的花岗岩基岩组成，但植被发育条件的不同。森林流域生物学活性的增加，通过有机物的矿化和N转化增加了净质子的产生。在森林流域，翻译的增加减少了河流径流。结果，通过COI D22E D2解离而产生的质子产生。当植物阳离子吸收的估计值包括在质子预算中时，森林开发将这些净质子生产的总和增加了2.3至4.0倍的裸露集水区。但是，这些质子生产中有96％以上是通过集水区内的风化和阳离子交换而消耗的。显然，这些净质子生产的总和是通过大气输入，n转化，阳离子的同化以及COI D22E D2的分离的总和受到年度降水量和年度径流的强烈影响。由于年降水的波动而导致的质子产量的方差几乎等于森林生长质子产生的增加范围。较少的