| 我国南方岩溶区和北方黄土区的大气CO2效应 |
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| 引用本文： | 万国江,王仕禄.我国南方岩溶区和北方黄土区的大气CO2效应[J].第四纪研究,2000,20(4):305-315. |
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| 作者姓名： | 万国江 王仕禄 |
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| 作者单位： | [1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵 [2]中国科学院地球化学研究所环境地球化学国家重点实,贵 |
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| 基金项目： | 国家自然科学基金!(批准号:49894170,49903007和49773207)，中国科学院“九五”重大项目!（批准号:KZ951-A1-402-06-04) |
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| 摘 要： | 我国南方岩溶区与北方黄土区都是巨大的碳库。碳酸盐的溶蚀及再结晶是两个碳库与大气ＣＯ２交换的重要过程；碳的区域平衡是评价化学风化消耗或逸散ＣＯ２的基础，岩溶区与黄土区在地球化学风化的环境背景。溶蚀过程，产物运移和归宿等差异很大。黄土区化学风化消耗大气ＣＯ２通量较岩溶区小。目前评价两类地区土壤与大气ＣＯ２的源汇关系尚不成熟，需要定量认识土壤ＣＯ２与下伏碳酸盐岩溶蚀或与下伏黄土次生碳酸盐化作用。岩溶区湖
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| 关 键 词： | 岩溶区 黄土区 土壤 二氧化碳 大气 地球化学 |
| 修稿时间： | 2000-05-20 |
EFFECTS OF THE ATMOSPHERIC CO_2 IN KARST AREA OF SOUTHERN AND LOESS AREA OF NORTHERN CHINA |
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| Wan Guojiang ,Wang Shilu.EFFECTS OF THE ATMOSPHERIC CO_2 IN KARST AREA OF SOUTHERN AND LOESS AREA OF NORTHERN CHINA[J].Quaternary Sciences,2000,20(4):305-315. |
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| Authors: | Wan Guojiang Wang Shilu |
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| Abstract: | In order to understand the rise trend of the atmospheric CO2, it is necessary to study the relationship of source and sink between CO2 and the geo-mass based on the outline of recent carbon cycle. The karat region in southern China is a giant carbon reservoir, as well as the area of loess cover in northern China. The dissolution and re-crystallizahon of carbonate are important processes in the exchange of atmospheric CO2 with above carbon reservoirs. It is simultaneously that both of carbonate and non-carbonate experience the chemical weathering. For example, only 2 / 3 of aquatic composition comes from calcite and dolomite in the Lake Hongfeng, though its catchment is a typical karat region. The dissolution of carbonate mineral in the area of loess cover is dominated by drought weather. Most of weathering solution penetrate down and re-crystallize to form the secondary carbonate in the lower layer, in the processes of which CO2 emission almost equates the amount of the consumed CO2. In comparison, the intensive dissolution of carbonals mainly takes place on the surface and/or cranny of carbonate rock in karst area. The part of dissolution product subsequently maybe re-crystallizes during transformation. Thus, assessing the CO2 consumption or emission due to the chemical weathering of carbonates must base on the carbon balance between the erosion and sedimentation. The flux of the constimed CO2 from atmosphere approximates 0.4mol / (m~2. a) in the watershed of the Lake Hongfeng. It is much more than in the area of loess covers. A part of soil is uncovered by the vegetation with lower organic matter in both loess and karst areas, in which the production of CO2 is different from the other soil. Particularly, the soil layer is very thin in karst region. Carbonate rock is dissolved by CO2 forming in the overiying soil. But loess layer is very thick. CO2 producing in the soil involves into the secondary carbonatation and leads to high concentration of CO2 in deeper layer of loess. In order to know the relationship between soil and inospheric CO2 in two kinds of geo-environments, it is necessary to research the geochemical processes, including: the dissolution of carbonate rock underlying soil in karst region and the secondary carbonatation in loess layer, quantificationally. Carbonate in lake sediments reflects not only the change of the atmospheric CO2, but also the balance between biological exchange and decomposition of organic matter in watershed. During the early diagenesis of sediments in the region of carbonate rock, HCO3, producing from the decomposition of organic matter, contyols the dissolution of the allogenic and endogenic carbonate and formation of authigenic carbonate by diffusion in pore water. The fixed organic carbon of the watershed preserved in sediments of Lake Erhai equates 0.01mol/(m~2. a), a half of which will return to the atmosphere with a residence bine of 40a. However, the fate of inorganic carbon is only 8.6% of organic carbon. |
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| Keywords: | karst area area of loess covers chemical weathering CO2 forming in the soil fate by deposition |
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