滩涂围垦对盐沼湿地碳收支的影响研究进展

发布时间：2018-11-06 18:29

【摘要】：滨海盐沼湿地是全球重要的碳库,也是典型的脆弱生态系统。近年来,随着人口的增加,滨海盐沼湿地围垦开发已经成为缓解区域人口压力,保障粮食安全,促进经济发展的一项重要措施,特别是在发展中国家。围垦活动过程中必然会改变原有生态系统碳循环的路径和模式,进而影响全球的碳收支平衡。通过对大量文献的检索与总结,对国内外3种滨海盐沼湿地类型(红树林盐沼湿地、河口潮滩盐沼湿地和海岸潮滩盐沼湿地)土壤有机碳含量、固碳速率、碳排放速率以及围垦后的变化进行梳理和概括,给出滨海盐沼湿地围垦后土壤碳循环的一般规律与变化趋势,结果表明:(1)欧美长期滩涂开发形成的认识与滩涂围垦后的生态环境效应演变不适用于东亚发展中国家的短期高强度农业围垦,应注重东亚地区海岸围垦方式下的碳效应研究;(2)从滩涂湿地有机碳含量及其固碳速率来看,红树林盐沼湿地最高,河口潮滩盐沼湿地次之,海岸潮滩盐沼湿地最低。土壤黏粒、团聚体和埋藏速率对其具有较为明显的正向效应;淹水频率、盐分、地下水位反之。滩涂围垦后土壤有机碳含量呈先降后增的趋势,其转折点在围垦后30年左右,水田耕作对滩涂土壤有机碳富集效果最明显;(3)滩涂盐沼湿地的主要碳排放方式是CH_4和CO_2,其中CO_2的排放强度和通量都较大,且以红树林盐沼湿地最高。芦苇和互花米草的土壤碳排放强度相比于光滩要大很多。涨潮的过程中湿地碳排放强度要明显低于涨潮前后。滩涂围垦后的土壤碳排放强度要明显高于自然滩涂土壤,特别是围垦后的旱田耕作下的CO_2排放。从监测的结果来看,围垦前滩涂湿地表现为较强的碳汇,而围垦后表现出较为明显的碳源。最后,提出今后研究的重点方向和内容:抓紧开展滨海盐沼湿地碳收支清单的制定;不同围垦方式对滨海盐沼湿地碳循环影响的定量表达;加强开展未来滨海围垦模式及其土壤碳循环响应的刻画与模拟研究。
[Abstract]:Coastal salt marsh wetland is an important carbon pool and a typical fragile ecosystem. In recent years, with the increase of population, reclamation and development of coastal salt marsh wetland has become an important measure to relieve regional population pressure, ensure food security and promote economic development, especially in developing countries. In the process of reclamation, the path and mode of carbon cycle in the original ecosystem will be changed, which will affect the balance of carbon budget in the world. The soil organic carbon content and carbon sequestration rate of three types of coastal salt marsh wetland (mangrove salt marsh wetland, estuarine tidal marsh wetland and coastal tidal flat salt marsh wetland) were studied by the retrieval and summary of a large number of literatures. The carbon emission rate and the changes after reclamation were summarized, and the general rules and trends of soil carbon cycle after reclamation in coastal salt marsh wetland were given. The results are as follows: (1) the understanding of long-term tidal flat development in Europe and the United States and the evolution of ecological environment effect after tidal flat reclamation are not suitable for short-term high-intensity agricultural reclamation in developing countries of East Asia. We should pay attention to the study of carbon effect in coastal reclamation in East Asia. (2) according to the organic carbon content and carbon sequestration rate of tidal flat wetland, mangrove salt marsh wetland is the highest, estuarine tidal flat salt marsh wetland is the second, and coastal tidal flat salt marsh wetland is the lowest. The soil clay, aggregate and burial rate have obvious positive effects on them, while the frequency of flooding, salt content and groundwater level are vice versa. Soil organic carbon content decreased first and then increased after tidal flat reclamation. The turning point was about 30 years after reclamation. The effect of paddy field tillage on soil organic carbon enrichment was the most obvious. (3) the main carbon emission modes of salt marsh wetland in tidal flat are CH_4 and CO_2,. The emission intensity and flux of CO_2 are both large, and the mangrove salt marsh wetland is the highest. The soil carbon emission intensity of Reed and Spartina alterniflora is much higher than that of Guang Tan. In the process of high tide, the carbon emission intensity of wetland is obviously lower than that before and after high tide. The carbon emission intensity of the soil after reclamation was significantly higher than that of the natural tidal flat soil, especially the CO_2 emission from the cultivated dry land. According to the monitoring results, the tidal flat wetland shows a strong carbon sink before reclamation, but obvious carbon source after reclamation. Finally, the key research directions and contents in the future are put forward: making carbon budget inventory of coastal salt marsh wetland, quantitative expression of different reclamation methods on carbon cycle of coastal salt marsh wetland; To enhance the future coastal reclamation model and soil carbon cycle response characterization and simulation.
【作者单位】：江苏师范大学地理测绘与城乡规划学院;南京大学地理与海洋科学学院;国土资源部海岸带开发与保护重点实验室;
【基金】：国家自然科学基金项目“江苏沿海滩涂围垦土地质量变化过程和生态响应”(编号:41230751) 江苏师范大学高校博士科研启动基金项目“沿海滩涂围垦土地土壤碳库时空演变及其机制——以江苏省如东县为例”(编号:15XLR017)资助~~
【分类号】：P748;X171

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