State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
J Environ Sci (China). 2012;24(6):1053-63. doi: 10.1016/s1001-0742(11)60877-2.
Two representative zones in Chongming Dongtan which faced the Yangtze River and East China Sea respectively were selected to study the variability of soil organic carbon (SOC) reservation capability between coastal wetland and riverside wetland in the Chongming Dongtan wetland as well as its mechanism by analyzing soil characteristics and plant biomass. The results showed the SOC content of riverside wetland was only 48.61% (P = 0.000 < 0.05) that of coastal wetland. As the organic matter inputs from plant litter of the coastal wetland and riverside wetland were approximately the same, the higher soil microbial respiration (SMR) of riverside wetland led to its lower SOC reservation capability. In the riverside wetland, the high soil microbial biomass, higher proportion of beta-Proteobacteria, which have strong carbon metabolism activity and the existence of some specific aerobic heterotrophic bacteria such as Bacilli and uncultured Lactococcus, were the important reasons for the higher SMR compared to the coastal wetland. There were additional differences in soil physical and chemical characteristics between the coastal wetland and riverside wetlands. Path analysis of predominant bacteria and microbial biomass showed that soil salinity influenced beta-Proteobacteria and microbial biomass most negatively among these physical and chemical factors. Therefore the low salinity of the riverside area was suitable for the growth of microorganisms, especially beta-Proteobacteria and some specific bacteria, which led to the high SMR and low SOC reservation capability when compared to the coastal area.
选取崇明东滩分别面向长江和东海的两个具有代表性的区域，通过分析土壤特性和植物生物量，研究了崇明东滩滨海湿地和滨江湿地土壤有机碳（SOC）保持能力的变异性及其机制。结果表明，滨江湿地的 SOC 含量仅为滨海湿地的 48.61%（P=0.000<0.05）。由于滨海湿地和滨江湿地的植物凋落物输入的有机物质大致相同，因此滨江湿地较高的土壤微生物呼吸（SMR）导致其 SOC 保持能力较低。在滨江湿地中，较高的土壤微生物生物量、具有较强碳代谢活性的β变形菌较高的比例，以及芽孢杆菌和未培养的乳球菌等一些特定的好氧异养细菌的存在，是其 SMR 高于滨海湿地的重要原因。滨海湿地和滨江湿地之间还存在土壤物理化学特性的差异。优势细菌和微生物生物量的路径分析表明，在这些物理化学因素中，土壤盐分对β变形菌和微生物生物量的负面影响最大。因此，滨江地区的低盐度有利于微生物，尤其是β变形菌和一些特定细菌的生长，这导致与滨海地区相比，其 SMR 较高，SOC 保持能力较低。
