【作者】 李林立；

【导师】 况明生；

【作者基本信息】 西南师范大学 ， 自然地理学， 2003， 硕士

【摘要】 岩溶生态系统是受岩溶环境制约的生态系统，以石生、早生及喜钙和地下空间为特征，一种由地质条件所决定的脆弱环境。岩溶生态系统的运行受到两个子系统的联合作用驱动，即无机方面的“岩溶动力系统”和生命方面的“遗传信息传递系统”，但主要受以碳、水、钙循环为中心的岩溶动力系统的控制。作为岩溶生态系统的一部分——表层带岩溶生态系统是由岩石、水、植被、土壤及其上的大气构成，与大气圈、生物圈直接联系，对全球第四纪尤其是全新世晚期碳循环表现出灵敏的响应。土壤作为表层带岩溶生态系统的核心部分，在岩溶过程中起着枢纽作用，它的存在使得大气降水与碳酸盐岩之间形成一个“过滤层”，赋予岩溶作用更广阔的时间和空间，其中土壤CO₂是个非常关键的因子，它是岩溶作用的重要物质来源，在岩溶动力系统中起着驱动力作用。已有的研究表明：参与岩溶作用的CO₂多数属于土壤中生物成因，也就是说，尽管岩溶作用是一种自然界无机化学作用，但碳的分布与转移及循环仍以生物活动为纽带的土壤碳积累为转化中心，土壤有机碳构成系统最大的碳库，土壤呼吸碳表现为该系统中最重要的碳流通途径，因此进行土壤CO₂浓度观测及其影响因子分析是研究表层带岩溶生态系统运行机制和全球碳循环的首要条件。 国土资源部岩溶动力学开放研究实验室以IGCP229、IGCP379和IGCP448项目为依托，开展了我国7个典型的表层带岩溶生态系统运行规律及其全球变化影响研究，而其中金佛山的观测、分析与研究则才刚刚起步，本文以金佛山西坡 摘 公碧潭幽谷为观测点，主要通过COZ浓度、温度和湿度的观测，开展林地表层带岩溶生态系统与裸地表层带岩溶生态系统COZ浓度特征及其变化规律的对比研究，这对进一步深入研究岩溶生态系统运行机制和全球碳循环以及开展全球岩溶生态对比有着重要意义。我们发现： 1．表层带岩溶生态系统土壤COZ浓度从地表向下依次增大，在无雨的条件下，土层COZ浓度的高低主要取决与温度、湿度。 2．由于植被覆盖类型不一样和所处的层位以及本身性质，表层带岩溶生态系统各层的COZ浓度随温度变化的幅度不一样，林地表层COZ浓度变化的幅度比深部大，裸地土下E0。ZCOZ浓度变化的幅度比表层和底层大，林层、灌层和草层COZ浓度变化的幅度依次变小。 3大气降水对表层带岩溶生态系统各层COZ有明显的“沉淀”作用，影响林地与裸地土壤各层COZ浓度降低的幅度主要取决于降雨的频率，其次才是降雨量，而影响植被——空气系统各层CO。浓度降低的幅度主要取决降雨量的大小，其次才是降雨的频率。 4．对林地和裸地土壤COZ释放量观测中，温度是影响土壤COZ释放量的主要因子，其次为土壤湿度和地表植被。更多还原

【Abstract】 It is generally accepted that karst ecosystem controlled by geology is fragile. This is the result of soluble rock dissolution, which brings about shortage in soil and water on the surface. So karst vegetation is charactered by Petrophile, Xerophile and Calciphihe in those areas where soil cover is very thin, and the underground drainage system is well developed. The running of karst ecosystem is controlled by two subsystems, which are karst dynamic system in inorganic life and genetic information transmitting system in organic life. But it is mainly drived by the karst dynamic system centered on the cycle of CO2-water-calcium. As one part of karst ecosystem, epikarst ecosystem is composed of rock, water, vegetation, soil, and atmosphere. It is sensitive to the global carbon cycle in Quaternary, especially in late Holocene. As a hard-core part of epikarst ecosystem, soil makes a hinge action in the karst process. It forms a leach layer between rainfalls and carbonate and gives a great much time and space in the karst process. Soil CO2, a very pivotal factor in the karst dynamic factors, makes an action of driving forces in karst dynamic system. New achievements having been obtained in this field show that CO2 participating in karst process in the epikarst dynamic system mainly comes from soil air CO2 created by the organic carbon, in other words, although karst is a kind of biochemistric action in nature, distribution and transmit and cycle of carbon rely on changes of soil organic carbon. Soil organic carbon is the greatest carbon storeroom. Soil respiration emission of CO2 is the most important passing entrance in carbon cycle of epikarst ecosystem. So it is chiefly that soil CO2 concentration and its influencing factors should be studied in ordered to learn the mechanism of epikarst ecosystem and global carbon cycle.Karst Dynamics laboratory, Ministry of land and resources, has been studied the mechanism of seven typical epikarst ecosystem and global changes through IGCP 299(Geology, Climate, Hydrology and karst Formation, 1990-1994) and IGCP 379(Karst Processes and the Carbon Cycle, 1995-1999) to IGCP 448(World Correlation of Karst Ecosystem, 2000-2004), while observation and analysis and research of epikarst ecosystem in Mt.jinfo have just been beginning. The thesis analyzes that based-on observational point of green pond and deep dell in the west slope of jinfo mountain, CO2 concentration and regularity of epikarst ecosystem contrasting woodland with uncovered land have been studied through the observation of temperature and humidity and CO2 concentration. The main results are as follows:1 .Soil CO2 concentration of epikarst ecosystem begins to increase in turn with the depth of soil, and it is mainly controlled by temperature and humidity without rain.2.The range of soil CO2 concentration varied with soil temperature is not the same for the soil layer and its characters and different vegetation: the varied range of topsoil is higher than that of deep soil at testing woodland; the varied range of soil layer (-20cm) is the highest than that of the other soil layers; the range of CO2 concentration varied with air temperature begins to increase in turn from woodslay and shrublay to herbage.3.It is clear that CO2 concentration of epikarst ecosystem has been influenced for rain. The varied range of soil CO2 concentration is mainly influenced by rain frequency, secondly the amount of rainfall for the epikarst ecosystem of woodland and uncovered land. The varied range of CO2 concentrations in vegetation air system are mainly influenced by the amount of rainfall, secondly the rain frequency.4.Soil respiration emission of CO2 at testing woodland and uncovered land changes sensitively with the three factors, such as soil temperature, vegetation and humidity. But it is mainly controlled by soil temperature, secondly humidity and vegetation.更多还原