Comparative Study On Carbon Sequestration Rate Of Typical Marsh Wetland In China

More and more evidence that climate change is a fact beyond doubt. In recent decades, the impact of climate change on various global ecosystem and human society has been fully confirmed. Wetland ecosystems are very sensitive to moisture, vulnerability significantly. Wetland ecosystem plays an important role in global climate change. Wetlands have wide distribution, high productivity, ecological services and diverse characteristics. Since the massive accumulation of organic matter, which has become an important carbon pools. Wetlands are considered to play an important role in the mitigation of atmospheric greenhouse gases(mainly CO2 and CH4) concentrations of. China had a lot of research achievements on wetlands carbon sequestration rates. However, a lot of limitation were restrict research steps, the extensive spatial distribution of wetlands, complicated geographical environment, the evaluator in different geographical environment wetland ecosystem carbon pools / source capabilities are still great uncertainty. Therefore, conducted in different geographical environment and human disturbance intensity in different wetlands carbon sequestration rate has important theoretical and practical significance.Freshwater marsh were chose as the research object in this study. Choose the eastern margin of the Tibetan Plateau Ruoergai wetland, Jiuzhaigou wetlands; Daxinganling Nanwenhe wetlands; Changbai Mountains Jinchuan wetlands; Honghe wetlands in Sanjiang Plain, wetland near Xingkai Lake as study sites. In total 230 soil samples were collected from field, and using field investigation, radioisotope dating laboratory testing and other methods analysis all samples. Determination of the wetlands soil bulk density, soil organic carbon, and soil nitrogen and soil phosphorus. Analysis all samples from different geographical environment by soil carbon sequestration rate and soil organic carbon density, then compare the difference between the rates of carbon sequestration. Discusses the main factors affecting the wetlands soil carbon sequestration rate. Jinchuan wetland in Changbai Mountain in Northeast, for example, measured particulate organic carbon in soil aggregates. Depicts the particulate organic carbon in soil aggregates profile distribution characteristics. At last use aggregate particulate organic carbon assessment of wetland soil organic carbon pool stability.The main research results are as follows:1. Bulk density comparison result shows that bulk density in Ruoergai wetland were minimum, Jinchuan wetlands, Nanwenhe wetlands, Jiuzhaigou wetland were in the middle. While Xingkai wetlands and Honghe Wetland density maximum; the range, the minimum Jinchuan wetlands fluctuation range, Honghe wetland in the middle, Nanwenhe Jiuzhaigou wetlands and wetlands maximum amplitude. The results showed that among 100 years Zoige wetlands, Jinchuan wetlands carbon sequestration process is relatively stable, while Nanwenhe and Jiuzhaigou wetlands fixed rate fluctuations between the carbon interannuals larger.2. Soil organic carbon content as a function of wetlands in carbon stocks strength determination index. Ruoergai natural wetlands and Jinchuan wetland has high soil organic carbon content. Soil organic carbon content in descending order is Ruoergai natural wetlands > Jinchuan wetlands> Ruoergai restore wetlands> Jiuzhaigou wetlands> Nanwenhe Wetlands> Honghe Wetland> Xingkai Lake wetland. Ruoergai wetland soil organic carbon content is more than 5 times with restored wetland soil organic carbon content. This result shows that restoration of wetlands soils is a slow process. Ruoergai natural wetlands and Jinchuan wetland has high soil organic carbon content. There has faster accumulation rate in wetlands organic carbon, but fluctuated between interannual large. In Nanwenhe wetlands and Xingkai lake wetlands and Honghe Wetland soil organic carbon content were in low level. Those wetland as a function of small carbon pool, however has a little fluctuations between years in little change over the past century. Carbon pool indicate that wetlands features in a relatively stable state.3. Ruoergai natural wetlands and Jinchuan wetland in soil TN content is higher than other wetlands. Those two sites is higher than Huahu wetland in soil TN content which is near Ruoergai wetland and is a restoration wetland. But those sites were higher than Jiuzhaigou wetland in soil TN content. Both of Honghe wetland, Xinkaihu wetland and Nanwenghe wetland are low concentration in soil TN content. Soil profile result shows that in Jinchuan wetland had maximum fluctuation range, while Nanwenghe wetland had minimum fluctuation range. The older of fluctuation range is Jinchuan wetland, Huahu weltnad, Jiuzhaigou wetland, Ruoergai wetland, Xingkaihu wetland, Honghe wetland and Nanwenghe wetland.4. Ruoergai wetland had highest TP content in all sites, and natural wetlands(1.10±0.29g/kg) is higher than restoration wetland(0.76±0.24g/kg). Jiuzhaigou wetland(0.29±0.08g/kg) is the third position in soil TP content. Jinchuan wetland, Honghe wetland, Xingkaihu wetland and Nanwenghe wetland had lower soil TP content. The author believes that it may had relationship with geological condition and climate condition. In soil profile, both of Ruoergai wetland and Jinchuan wetland had a large fluctuation range in soil TP content, while in Xingkaihu wetland and Honghe wetland the fluctuation range is the lowest. Temperature, hydrology, primary production plants, vegetation type, soil nutrients, etc., are exerting influence on soil carbon function.5. Carbon sequestration rate play a key indicator in measure of the wetland as a carbon pool function strength. The result shows that, Jinchuan wetland and Nanwenghe wetland has a higher carbon sequestration and enrichment of nutrients nitrogen and phosphorus capacity than Honghe wetland. Wetland degradation greatly reduced the wetland as a carbon pool function, Jiuzhaigou wetland had lowest carbon sequestration rate than other sites. Wetlands deposition rate and total nitrogen and the precipitation was positively correlated(P <0.001)6. Soil aggregates play a key role in the process of carbon sequestration in wetlands, also it can be seen a reference index to judge the age of wetland development. Proportion of micro-aggregates in wetland will affect the carbon sequestration capacity and carbon pool stability. Soil aggregates in Jinchuan wetland shows a differences with climate change and soil depth in the distribution of state. The result shows that, carbon sequestration rate was very high near 1873, besides the soil particulate organic carbon content is correspondingly higher. All the evidence shows that in that period the natural environment is better than now. In deep depth of Jinchuan wetland soil profile, Macro-aggregates take more proportion than micro-aggregates. It can be seen another proof to judge Jinchuan wetland is very young age in development as well.