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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

为了研究森林生长对酸缓冲过程的各种影响，在三个不同的温带集水区进行了水化学观测，每个集水区都有相同的花岗岩基岩，但森林的生长条件和土壤深度不同。这些流域的水文过程分为：（1）穿透过程，（2）土壤入渗过程，（表面和地下土层入渗子过程，饱和地下水转移子过程）和（3）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。具体观察到的变化伴随着植被的生长：（1）有机质的分解产生的质子和（2）除了化学风化，阳离子交换过程开始消耗质子在表层土壤层。(3)因此，质子的产生相对 ...更多信息土壤表层的质子消耗量大于消耗量，一些未被消耗的质子被转移到地下土壤层并被消耗。具体观察到的与土壤深度有关的变化是：（1）随着土层变厚，地下水中的pCO含量增加。(2)结果表明，脱气后的pH值随着土壤深度的增加而增加。第二，量化森林植被对酸缓冲过程的影响，水化学观测数据为两个独立的年份被用来计算质子预算在三个小集水区，每个集水区由相同的花岗岩基岩，但不同的植被发育条件。在森林集水区的生物活动的增加，增加了净质子生产的有机物和N转化的矿化。在森林覆盖的集水区，蒸腾作用的增加减少了径流。其结果是，由CO β D22 β D2解离产生的质子减少。当植被的阳离子吸收的估计值包括在质子预算，森林开发增加了这些净质子生产的总和的2.3至4.0倍，裸露的集水区。然而，超过96%的这些质子生产消耗的风化和阳离子交换集水区内。很明显，这些净质子生产的大气输入，氮转化，同化的阳离子，和解离的CO的D22的D22的总和是强烈的影响，年降水量和年径流量。年降水量波动引起的质子产生量的变化几乎等于森林生长引起的质子产生量增加的幅度。少