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 ...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 β-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 β-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 β-Proteobacteria and some specific bacteria,which led to the high SMR and low SOC reservation capability when compared to the coastal area.展开更多
根据西藏2607个土壤剖面资料和1：200万土壤图的数字化处理,按地区以制图单元土壤亚类为基础估算土壤有机碳密度（SOCD）和储量（SOCR）,并探讨其空间分布特征.结果表明：（1）西藏地区的SOCD平均为7.48 kg m^-2,并随土壤类型而变化,以...根据西藏2607个土壤剖面资料和1：200万土壤图的数字化处理,按地区以制图单元土壤亚类为基础估算土壤有机碳密度（SOCD）和储量（SOCR）,并探讨其空间分布特征.结果表明：（1）西藏地区的SOCD平均为7.48 kg m^-2,并随土壤类型而变化,以山地铁铝土最高（29.2 kg m^-2）,其后依次是山地淋溶土（16.6 kg m^-2）、高山草甸型土壤（12.2 kg m^-2）、山地半淋溶土（9.2kgm^-2）、高山草原型土壤（3.7kg m^-2）等,而以寒冻土（1.6kg m^-2）和高山荒漠土（1.3kg m^-2）为最低.同时土壤表层（0～20cm）的SOCD平均为4.27 kg m^-2,占全剖面总量的57﹪,反映西藏地区土壤有机碳库（SOCP）对环境变化具有较高的敏感性.（2）西藏SOCD具有独特的水平地带分布,即自藏东南向西北逐次降低,由此可大体分为高（Ⅰ）、中（Ⅱ）、低（Ⅲ）、极低（Ⅳ）4个碳密度带,其平均SOCD分别为21、10、4、＜2 kg m^-2;各带SOCD又有不同的垂直分布,总趋势是由复杂到简单,但均以最高位置的寒冻土极低碳密度为终点.（3）西藏SOCR总计为8.23 Pg,占全国SOCR总量的9.14﹪.各地SOCR分布极不平衡：就各碳密度带的SOCR相对比例（占西藏全区总量﹪）而言,Ⅰ、Ⅱ、Ⅲ、Ⅳ带分别为25﹪、50﹪、22﹪、3﹪,其中Ⅰ、Ⅱ带合计的土壤面积仅占45﹪,而SOCR却占75﹪,因而是西藏SOCP的主体;而反映土壤储碳能力的丰度指数（R）则分别为2.82、1.37、0.53、0.23.就各地区的SOCR而言,以那曲地区最大（2.19Pg）,拉萨地区最小（0.31Pg）;而R值则是林芝＞山南＞拉萨＞昌都＞日喀则＞那曲＞阿里.这些结果将为全球变化研究与区域环境评价提供有力的支撑.展开更多
基金supported by the National Major Scientific and Technological Project of China (No.2010BAK69B13,2010BAK69B14)the Major Project of the Shanghai Scientific and Technological Committee(No. 10dz1200903,10dz1200700)
文摘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 β-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 β-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 β-Proteobacteria and some specific bacteria,which led to the high SMR and low SOC reservation capability when compared to the coastal area.
文摘根据西藏2607个土壤剖面资料和1：200万土壤图的数字化处理,按地区以制图单元土壤亚类为基础估算土壤有机碳密度（SOCD）和储量（SOCR）,并探讨其空间分布特征.结果表明：（1）西藏地区的SOCD平均为7.48 kg m^-2,并随土壤类型而变化,以山地铁铝土最高（29.2 kg m^-2）,其后依次是山地淋溶土（16.6 kg m^-2）、高山草甸型土壤（12.2 kg m^-2）、山地半淋溶土（9.2kgm^-2）、高山草原型土壤（3.7kg m^-2）等,而以寒冻土（1.6kg m^-2）和高山荒漠土（1.3kg m^-2）为最低.同时土壤表层（0～20cm）的SOCD平均为4.27 kg m^-2,占全剖面总量的57﹪,反映西藏地区土壤有机碳库（SOCP）对环境变化具有较高的敏感性.（2）西藏SOCD具有独特的水平地带分布,即自藏东南向西北逐次降低,由此可大体分为高（Ⅰ）、中（Ⅱ）、低（Ⅲ）、极低（Ⅳ）4个碳密度带,其平均SOCD分别为21、10、4、＜2 kg m^-2;各带SOCD又有不同的垂直分布,总趋势是由复杂到简单,但均以最高位置的寒冻土极低碳密度为终点.（3）西藏SOCR总计为8.23 Pg,占全国SOCR总量的9.14﹪.各地SOCR分布极不平衡：就各碳密度带的SOCR相对比例（占西藏全区总量﹪）而言,Ⅰ、Ⅱ、Ⅲ、Ⅳ带分别为25﹪、50﹪、22﹪、3﹪,其中Ⅰ、Ⅱ带合计的土壤面积仅占45﹪,而SOCR却占75﹪,因而是西藏SOCP的主体;而反映土壤储碳能力的丰度指数（R）则分别为2.82、1.37、0.53、0.23.就各地区的SOCR而言,以那曲地区最大（2.19Pg）,拉萨地区最小（0.31Pg）;而R值则是林芝＞山南＞拉萨＞昌都＞日喀则＞那曲＞阿里.这些结果将为全球变化研究与区域环境评价提供有力的支撑.
