黄河三角洲湿地是典型的滨海湿地，是陆地-海洋-大气相互作用最活跃的地带，是全球环境变化的缓冲区。滨海湿地在净化环境、减轻灾害、保护海岸线和维持生物多样性中发挥着重要作用。黄河三角洲滨海湿地生态系统中生物地球化学过程十分复杂，各种物理、化学和生物过程共同控制着有机质在湿地中的赋存与转化。因此加强滨海湿地基础研究对于合理开发利用和保护滨海湿地具有重要的现实意义。为了更深入的了解黄河三角洲滨海湿地碳的生物地球化学循环特征及其关键机制，本研究以黄河三角洲典型湿地植物-土壤系统为研究对象，通过野外样品采集、原位实验和室内试验，研究了湿地土壤有机碳的储量、时空分布与化学转化特征，探讨了湿地植物生物量与碳累积季节变化特征以及湿地植物残体分解及分解过程碳动态变化特征，建立了湿地植物-土壤系统碳循环分室模式，主要结论如下：1）黄河三角洲滨海湿地研究区表层土壤（0-30 cm）有机碳密度范围是0.73-4.25 kg·m^-2，碳储量为1.7´10⁶ t。2）研究区植物生物量均具有明显的季节变化特征，且新生湿地总生物量高于退化湿地。土壤盐分含量是该研究区植被空间分布的主要限制因素。3）生长季内芦苇、碱蓬地上器官（茎、叶、种子）的碳累积量分别为18.23-480.61 g·m^-2和31.5-230.46 g·m^-2，根系碳累积量为198.45-365.24 g·m^-2和9.11-57.95 g·m^-2，枯落物碳累积量分别为33.21- 233.55 g·m^-2 和15.04-99.54 g·m^-2。除生长初期外，芦苇器官（根、茎、叶）的碳累积量均明显高于碱蓬。4）两种类型湿地枯落物分解随时间的变化总体趋势相同，即随着时间的延长失重率呈增大趋势；分解速率范围是0.001-0.0027 d^-1，在一定程度上受气温波动的影响，但随时间延长，分解速率总体上呈下降趋势。相关分析表明枯落物性质、湿地气候条件以及湿地土壤酸碱显著影响植物残体分解。在分解过程中，残留物中碳元素呈明显波动变化，整体呈增加趋势，C/N比递减。5）在生长季内黄河三角洲湿地土壤有机碳含量范围在0.49-10.41 g·kg^-1之间，明显低于其他内陆沼泽湿地。垂直剖面上大致呈现逐渐下降规律，季节变化剧烈。黄河三角洲滨海湿地土壤养分的水平分布规律与滨海湿地植物群落、土壤盐分状况、营养元素的化学性质及潮汐等关系密切。相关分析表明，土壤有机碳含量与pH负相关，与土壤全氮、C/N、粘土含量正相关（p<0.01），与土壤容重之间存在不显著负相关性，与土壤含水量无相关性。6）土壤轻组分含量极少，约为0.008%-0.15%，随剖面深度增加而减少。重组组分比例均高于99%说明该研究区土壤有机碳的主要组成部分是重组有机碳。重组有机碳在土壤剖面分布特征与土壤有机碳分布特征一致，随土壤深度呈一定的高低波动变化，芦苇湿地土壤有机碳及重组有机碳含量平均高于碱蓬湿地。相关分析表明，土壤轻重组分比例与SOC没有相关性，而土壤重组有机碳含量与SOC显著正相关（p<0.01）。7）湿地土壤颗粒组分比例季节变化范围是1.9%-62.9%，颗粒组分季节波动剧烈，垂直剖面上呈M型分布。湿地表层土壤（0-10cm）颗粒组分中碳含量相对较高。土壤颗粒有机碳含量低，随剖面深度增加而递减。相关分析表明，土壤颗粒组分碳含量和颗粒有机碳含量与土壤有机碳含量都呈现了显著的正相关关系。8）生长季内芦苇、碱蓬湿地可溶性有机碳含量均值变化范围分别是93.87-221.79 mg·kg^-1， 126.00-211.16 mg·kg^-1。季节变化明显，生长季内呈M型分布。在垂直剖面上土壤可溶性有机碳含量分布无明显的一致性规律。9）通过70d的培养期间，土壤的总累积矿化量为0.71 mg C·kg^-1-476.47 mg C·kg^-1。在培养初期(0-3d)，矿化速率迅速上升，随着培养时间的进行矿化速率迅速下降并在培养后期趋于稳定。温度、水分以及土层深度均对土壤有机碳矿化有显著影响。一级动力学方程能较好地描述湿地土壤有机碳矿化动态。10）建立了两种植物-土壤系统碳循环分室流动模式，确定了不同分室的碳储量以及分室间的碳流通量。

The Yellow River Delta wetland is typical coastal wetland, located in the interactive areas between land and sea. It is a very important ecosystem, which is sensitive to the global change and human activities. Coastal wetlands play an important role in cleaning up the environment, mitigating disaster, protecting the coastline and maintaining biological diversity. Biogeochemical processes in the Yellow River Delta wetland ecosystem are enormously complex. Therefore, basic research of coastal wetlands is important for developing and protecting coastal wetlands. In this paper, typical plant-soil estuary wetlands were selected as study objects in order to understand the carbon biological cycle rule and its key mechanism. The experiments were performed from June 2009 to November 2011 to study the storage, temporal-spatial distribution and transformation characteristics of organic in wetland soils, the seasonal dynamics of plant biomass and carbon accumulation, litter decomposition rules and carbon dynamics in the decomposition process. Finally, the carbon biological cycling compartment model of plant-soil system was established. The main results were drawn as follows: 1) The soil organic carbon density ranged from 0.73-4.25 kg·m^-2 in 0-30cm, and the store was 1.7´10⁶ t. 2) The phytomass varied seasonally and it in newborn wetland was higher than the degraded wetlands. The soil salt content is a major limiting factor for the vegetation spatial distribution. 3) During the growing season, the carbon accumulation in Reed and Suaeda aboveground organ was 18.23-480.61 g·m^-2 and 31.5-230.46 g·m^-2 respectively, 198.45-365.24 g·m^-2 and 9.11-57.95 g·m^-2 in roots, 33.21- 233.55 g·m^-2 and 15.04- 99.54 g·m^-2 in litters. In addition to the initial growth stage, reed organs accumulated more carbon than Suaeda. 4) Litter decomposition of the two types of plant had a same trend and the weight loss rate decreased with time. Decomposition rate ranged from 0.001 to 0.0027d^-1, influenced by the temperature, and it decreased with time as well. Correlation analysis showed that the litter specifity, climatic conditions and soil pHseriously affected decomposition of plant residues. During the decomposition process, the carbon content in the litter residues changed significantly, presented an increasing tendency, C/N decreased instead. 5) Soil organic carbon content ranged from 0.49 to 10.41 g·kg^-1. The vertical distribution of SOC in different periods had higher variability, which were mainly correlated with tide effects, clay content, soil pH and the effects of terrestrial sources. The carbon contents in wetland soil had markedly seasonal characteristics, which were greatly affected by water condition and tidal influence. 6) The range of soil light fraction ratio was 0.008%-0.15% in this study region, therefore the heavy fraction organic carbon was dominant component of SOC. The HFOC distribution characteristic was the same as SOC, and they had significant positive correlation. 7) The range of soil particulate fraction ratio was 1.9%-62.9%, and showed M-type distribution at vertical profiles. Particulate organic carbon content was low and decreased as soil depth increase. There was a significant positive relationship between POC and SOC. 8) Dissolved organic carbon in reed wetland was 93.87-221.79 mg·kg^-1, and 126.00-211.16 mg·kg^-1 in Suaeda wetland. DOC content changed seasonally. 9) The results of incubation experiment showed that carbon mineralization rates decreased with soil depth, increased with temperature, and reached the highest at optimal moisture (60% WHC) at the same temperature. Total carbon mineralization of was significantly affected by soil temperature and moisture. Total mineralized carbon ranged from 0.71 mg C·kg^-1 to 476.47mg C·kg^-1. 10) The carbon cycling compartment model of plant-soil system in wetland was established, and carbon stocks of different compartments and the carbon turnovers among compartments were calculated.