崇明东滩潮间带硫酸盐还原菌及有机质含量的初步研究

针对崇明东滩湿地不同潮滩和不同高程的土壤采样,进行了MPN法微生物计数、沉积物有机质含量的测定,计算了SO42-和Cl-浓度的摩尔比,研究了硫酸盐还原菌的分布状况、与有机质含量的相关性、以及植物根际环境对其生长的影响.结果表明,不同高程潮滩同一深度的硫酸盐还原菌数量,按大小排序为:中潮滩高潮滩光滩.同一潮滩不同深度的硫酸盐还原菌含量,均显示为51～52 cm21～22 cm81～82 cm,说明东滩湿地51～52 cm的土壤深度是硫酸盐还原菌生长的主要层位,与存在较好的适于硫酸盐还原菌生长的条件有关.不同深度土壤中的有机质含量,呈现高潮滩中潮滩光滩的趋势.从21～51 cm处,随着深度的增加,有机质含量减少但硫酸盐还原菌的数量却大幅增加,说明硫酸盐还原菌利用土壤中的有机质进行了还原反应.所有土壤样品的SO42-/Cl-摩尔比值均0.05,表明硫酸盐还原菌十分活跃地进行着硫酸盐还原作用.芦苇根际中硫酸盐还原菌含量是最高的,说明东滩湿地芦苇的根际环境对硫酸盐还原菌的生长具有促进作用,而藨草根际的硫酸盐还原菌数量相对非根际环境较低,说明不同的根际效应对于东滩硫酸盐还原菌的生长有不同的影响.

Primary Study on Contents of Sulfate Reducing Bacteria (SRB) and Organic Matter from Intertidal Zone at Chongming Dongtan

Collected soil samples from different tidal flats and elevation in Chongming Dongtan wetland, then conducted sulfate-reducing bacteria (SRB) based on MPN method, determined organic matter content and calculated SO4(2-)/Cl- molar ratio, for the research on the distribution of SRB, relevance to soil organic matter content as well as influence of plant rhizosphere environment on SRB growth. The results show the distribution of SRB is ranked as middle flat > climax flat > bald flat. The same tidal flats at different depths, the SRB levels are shown as 51-52 cm > 21-22 cm > 81-82 cm, therefore 51-52 cm soil depth of Dongtan wetland is the suitable area for SRB to grow. However, in different tidal and depth, the distribution of organic matter content presents climax flat > middle flat > bald flat. From 21-51 cm, as the depth increasing, the organic matter content decreases while the amount of SRB significantly increasing, which indicates SRB utilizes the soil organic matter to carry out reduction reaction. The SO4(2-)/Cl- molar ratios of all soil samples are less than 0.05, indicating that SRB are actively engaged in sulfate reduction. The concentration of SRB in reed rhizosphere soil is the highest, showing that Phragmites australis rhizosphere environment in Dongtan wetland could enhance SRB growth, while the number of SRB in Spartina alterniflora rhizosphere environment is relatively lower than the non-rhizosphere environment, indicating that the rhizosphere effect has different effects on SRB in Dongtan tidal flats.