Changes and Future Prediction in the Dynamics of Dissolved Organic Matter in Soils under Forest Ecosystems by Global Warming

全球变暖导致森林生态系统土壤溶解有机物动态变化及未来预测

基本信息

批准号：
15310005
负责人：
HIGASHI Teruo
金额：
$ 6.72万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

In order to investigate the changes and future prediction in the dynamics of dissolved organic matter (DOM) in the O horizon of soils under forest ecosystem due to global warming and temperature increase, DOM after an incubation experiments of O horizon samples under different temperatures for 80days extracted with water and also the DOM in the leaching solution from O horizon under the "Warming Chamber" made of plastics of acryl resins were subjected to the various analyses, especially their chemical composition.Two representative study sites were selected, one was the Kawakami Experimental Station of Forestry, University of Tsukuba where a typical cool temperate forest ecosystems composed of mainly broad-leaved trees (Qerccus Mongolia spp.) growing on an acid brown forest soils (Dystric Cambisols), and the other was the Oodarumi National Forest where a typical sub-frigid forest ecosystems composed of mainly needle-leaved trees (Abies spp.) growing on a podzolic soils (Typic Podzols). … More The simulated experiment for the "Warming Chamber" was conducted during the period from 2003 to 2005 except for winter times. The results obtained were as follows.1)Concentration of dissolved organic carbon (DOC) in the extracts of O horizon sample increased after the incubation for 80days, especially for the samples under 15℃. The proportion of hydrophilic components of DOM also increased after the incubation as well as extracted cations including calcium, magnesium, potassium, sodium, aluminum and iron. The changes in the chemical structure were inferred from the absorbance at 285nm per DOC,IR spectra and elemental compositions, suggesting the increase in the aromatic carbon with lower "saturation degree".2)DOC concentration in the leaching solutions increased for the sites under simulated "Warming Chamber" where about 0.5℃ increase in the mean day temperature was observed in the O horizon, suggesting that the higher decomposition rate would be plausible as detected by the measurement of soil respiration rate for the elevated temperature conditions resulting in the release of more aromatic components of DOM. However the increase in the proportion of hydrophilic components of DOM was not clearly detected in the field conditions. Moreover changes of soil properties were observed especially for those in the surface horizons.3)The increase in temperature, possibly global warming, increase the amount of DOM of aromatic carbon with lower "saturation degree" like phenol and fulvic acids-like substances, and lead to the changes in the properties of soils of surface horizons.From the comparative study on the two study sites mentioned above it is suggested that the effect of global warming on the amounts and the composition of DOM would be more apparent in the areas under the forest ecosystems of cooler climate. Thus the fundamental knowledge on the dynamics of DOM from forest ecosystems under prevailing global warming was obtained through this project. Less

为了研究全球变暖和温度升高导致森林生态系统土壤O层中溶解性有机物（DOM）动态的变化和未来预测，对O层样品在不同温度下进行80天的培养实验后的DOM用水提取的有机物以及丙烯酸树脂塑料制成的“加热室”下的 O 地平线浸出液中的 DOM 进行了各种分析，特别是它们的化学成分。选择了两个有代表性的研究地点，一是筑波大学川上林业实验站是典型的冷温带森林生态系统，主要由生长在酸性棕色森林土壤（Dystric Cambisols）上的阔叶树（蒙古栎）组成，另一个是大田国立森林，典型的亚寒带森林生态系统，主要由生长在灰化土上的针叶树（冷杉属）组成（典型… 更多 2003年至2005年（冬季除外）期间进行了“加温室”模拟实验，得到的结果如下： 1）O地平线样品提取物中溶解有机碳（DOC）的浓度增加。孵育80天后，特别是对于15℃下的样品，孵育后DOM的亲水成分比例也增加，包括提取的阳离子。从DOC 285nm 处的吸光度、红外光谱和元素组成推断出化学结构的变化，表明芳香碳含量增加，且“饱和度”较低。2)模拟“变暖室”下的浸出溶液中的 DOC 增加，在 O 层中观察到平均日温度浓度增加约 0.5℃，这表明较高的分解速率是合理的：通过测量土壤呼吸速率发现，高温条件导致更多 DOM 芳香成分的释放，但在田间条件下并未明显检测到 DOM 亲水成分比例的增加。 3）温度升高，可能是全球变暖，使苯酚和富里酸类物质等“饱和度”较低的芳香碳中的DOM含量增加，并导致的属性通过对上述两个研究地点的比较研究表明，全球变暖对 DOM 数量和组成的影响在气候较冷的森林生态系统下的区域更为明显。通过该项目获得了有关当前全球变暖下森林生态系统 DOM 动态的基础知识。