水盐梯度对闽江河口湿地土壤有机碳组分的影响

发布时间：2018-08-11 18:52

【摘要】：为了揭示水盐梯度对河口湿地土壤有机碳组分的影响,对闽江河口不同淹水环境和盐度下短叶茳芏(Cyperus malaccensis)湿地土壤活性有机碳含量进行了测定与分析.结果表明,无论半咸水湿地还是淡水湿地,土壤微生物生物量碳(MBC)含量均随淹水频率增加而增加,增幅分别为67.8%和38.8%.半咸水湿地高低潮滩的土壤MBC含量均低于淡水湿地,高低潮滩降幅分别为52.9%和43.1%.半咸水湿地高低潮滩土壤可溶性有机碳(DOC)含量均高于淡水湿地,增幅分别为56.7%和105.6%.2种湿地土壤易氧化有机碳(EOC)含量均随淹水频率增加而降低,半咸水湿地高低潮滩间降幅18.0%,淡水湿地降幅50.1%.半咸水湿地高低潮滩土壤EOC含量均高于淡水湿地,增幅分别为20.2%和97.4%.微生物熵以及DOC和EOC占SOC的比值分别为0.42%~1.76%、0.39%~0.85%和20.14%~36.49%.微生物熵随盐度增加而降低,土壤DOC和EOC的分配比例随盐度的增加而增加.相对于淹水环境变化,土壤TN含量和电导率对SOC及其活性组分含量影响的贡献更大.土壤DOC、EOC与SOC显著正相关,土壤MBC与SOC、EOC和DOC均呈负相关,暗示底物的有效性和土壤MBC周转速率是影响土壤微生物活性和碳库积累的重要因子.淹水频率增加提高了土壤微生物的数量,但土壤微生物对淹水环境有一定的适应机制.盐度增加可提高土壤DOC、EOC含量,但降低土壤MBC含量.土壤氮含量和盐度是影响闽江河口湿地生态系统土壤碳库演变的重要限制性参数.
[Abstract]:In order to reveal the effect of water and salt gradient on soil organic carbon composition of estuarine wetland, the soil active organic carbon content of (Cyperus malaccensis) wetland under different flooded environment and salinity in Minjiang River estuary was determined and analyzed. The results showed that the soil microbial biomass carbon (MBC) content increased with the increase of flooding frequency (67.8% and 38.8% respectively) in both brackish and freshwater wetlands. The soil MBC content of brackish wetland was lower than that of fresh water wetland, and the decrease of high low tide beach was 52.9% and 43.1%, respectively. The content of soluble organic carbon (DOC) in soil in brackish wetland was higher than that in fresh water wetland, the increase was 56.7% and 105.6.2%, respectively. The content of (EOC) decreased with the increase of flooding frequency. In brackish water wetland, the decrease was 18.0 between high and low tide and 50.1 in freshwater wetland. The content of EOC in the soil of brackish wetland was higher than that of fresh water wetland, with an increase of 20.2% and 97.4%, respectively. The microbial entropy and the ratio of DOC and EOC to SOC were 0.42% and 0.39%, 0.85% and 20.14%, respectively. The microbial entropy decreased with the increase of salinity, and the distribution ratio of DOC and EOC increased with the increase of salinity. The effects of TN content and conductivity on the content of SOC and its active components were more significant than those in flooded environment. Soil MBC was significantly positively correlated with SOC, and soil MBC was negatively correlated with SOC- EOC and DOC, suggesting that the availability of substrates and the turnover rate of soil MBC were important factors affecting soil microbial activity and carbon pool accumulation. The increase of flooding frequency increased the number of soil microbes, but soil microbes had a certain adaptation mechanism to flooded environment. The increase of salinity can increase the content of MBC in soil, but decrease the content of MBC in soil. Soil nitrogen content and salinity are important limiting parameters affecting the evolution of soil carbon pool in the wetland ecosystem of Minjiang River estuary.
【作者单位】：中国科学院东北地理与农业生态研究所湿地生态与环境重点实验室;福建师范大学地理科学学院;福建师范大学亚热带湿地研究中心;
【基金】：国家“973”项目(2013CB430401) 中国博士后科学基金(2017M611337) 国家自然科学基金资助(41371127)
【分类号】：S153.6

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