【作者】 佘晨兴；

【导师】 仝川；

【作者基本信息】 福建师范大学 ， 自然地理学， 2014， 博士

【摘要】 应用PCR-RFLP技术、克隆测序及实时定量PCR技术对闽江河口鳝鱼滩湿地3个不同优势沼泽植被带土壤中产甲烷菌和硫酸盐还原菌的群落结构、丰度及其空间分布特征进行了研究,同时分析了产甲烷菌和硫酸盐还原菌的群落结构、丰度与土壤理化因子、甲烷产生速率之间的关系。闽江河口芦苇、短叶茳芏、互花米草湿地土壤(0-30cm)中检测到的产甲烷菌类群包括：甲烷杆菌目(Methanobacteriales)、甲烷微菌目(Methanomirobiales)、甲烷八叠球菌目(Methanosarcinales)和甲烷球菌目(Methanococcales)。甲烷微菌目(Methanomirobiales)是闽江河口鳝鱼滩湿地3个优势植被带沼泽湿地的优势类群,暗示闽江河口湿地0-30cm土层甲烷产生的主要途径为H2/CO2.不同植被类型的湿地土壤中,产甲烷菌的主要菌属各不相同；在同一植被类型湿地不同土壤深度中,产甲烷菌群落的分布也呈现出垂向变化的特征。Methanoregula在3种植被类型湿地中均为优势菌属。芦苇、短叶茳芏、互花米草湿地土壤(0-30cm)中产甲烷菌数量的平均值依次为3.72×108copies g-1dws、3.39×107copies g-1dws和5.68×107copies g-1dws。芦苇沼泽湿地土壤(0-30cm)产甲烷菌的平均丰度显著高于短叶茳芏沼泽湿地产甲烷菌的平均丰度(F(1,16)=20.581,P<0.001)和互花米草沼泽湿地产甲烷菌的平均丰度(F(1,16)=17.751,P<0.001)。此外,同一植被类型不同土壤深度中产甲烷菌的丰度也呈现出垂向变化特征。闽江河口芦苇、短叶茳芏和互花米草沼泽湿地土壤(0-30cm)中检测到硫酸盐还原菌的类群包括：脱硫弧菌目(Desulfovibrionales)、脱硫杆菌目(Desulfobacterales)、互营杆菌目(Syntrophobacterales)和梭菌目(Clostridiales),其中脱硫杆菌目(Desulfobacterales)是优势类群。不同植被类型湿地土壤中硫酸盐还原菌的主要菌属各不相同,在同一植被类型湿地不同土壤深度中硫酸盐还原菌群落的分布也呈现出垂向变化的特征。Desulfosarcina和Desulfobacterium在3种植被类型湿地中均为优势菌属。芦苇、短叶茳芏、互花米草沼泽湿地土壤(0-30cm)中硫酸盐还原菌数量的平均值依次是8.95×107copies g-1dws、1.55×107copies g-1dws和2.40×107copiesg-1dws。芦苇沼泽湿地土壤(0-30cm)硫酸盐还原菌的平均丰度显著高于短叶茳芏沼泽湿地的平均丰度(F(1,16)=26.449,P<0.001)和互花米草沼泽湿地的平均丰度(F(1,16)=19.013,P=0.001)。同一植被带不同土壤深度中硫酸盐还原菌的丰度也呈现出垂向变化的特性。通过回归及相关分析发现,产甲烷菌的丰度与土壤有机碳含量符合冥函数方程硫酸盐还原菌的丰度与土壤有机碳含量符合对数函数方程而与其它土壤理化因子相关性不显著(P>0.05)。RDA和CCA分析表明：产甲烷菌群落组成与盐度具有极显著的相关性(P=0.002),与pH具有显著的相关性(P=0.036),与SOC、TN、SOC/TN不具有显著的相关性(P>0.05)；硫酸盐还原菌的群落组成与pH具有极显著的相关性(P=0.004),与土壤含水量(SMC)具有显著的相关性(P=0.022),与SOC、TN、SOC/TN、盐度不具有显著的相关性(P>0.05)。3种植被带土壤综合分析显示甲烷产生速率随产甲烷菌和硫酸盐还原菌丰度的增加而显著提高(但相关性较弱,R2和P值分别为：和对单个植被带进行回归分析,仅短叶茳芏沼泽土壤甲烷产生速率与产甲烷菌丰度有显著的线性回归关系单个植被类型沼泽湿地土壤甲烷产生速率与硫酸盐还原菌丰度均没有显著的相关关系(P>0.05,n=9)。更多还原

【Abstract】 The community structure, abundance and vertical profile characteristics of methanogens and sulfate-reducing bacteria were determined using PCR-RFLP technology, sequencing and real-time qPCR in three different vegetation type marshes in the Min River estuarine marsh. The relationships between diversity of the functional microbial groups and methane production rates and soil physicochemical factors were also analysised. Methanobacteriales, Methanomirobiales, Methanosarcinales and Methanococcales were detected at a soil depth of0-30cm in the Phragmites australis marsh, Cyperus malaccensis marsh, Spartina alterniflora marsh. Methanomirobiales was the dominant groups at a soil depth of0-30cm in the Min River estuarine marsh. It indicated that the main pathway of methane production at a depth of0-30cm in the Min River estuarine marsh was H2/CO2because Methanomirobiales was belonged to hydrogenotrophic methanogens. The main genera of methanogen varied with different vegetation types. In addition,the distribution of methanogen communities also presented the vertical change at different soil depth in the same vegetation types marsh. Methanoregula was dominant genus in the three vegetation types marsh. The average abundance of methanogen in the P. australis marsh, C. malaccensis marsh,S. alterniflora marsh determined by real-time quantitative PCR technology were3.72×108copies g-’dws,3.39×107copies g-1dws,5.68×107copies g-1dws, respectively. The average abundance of methanogen at a depth of0-30cm in P. australis marsh soil was significantly higher than that of C. malaccensis marsh(F (1,16)=20.581, P<0.001), and also significantly higher than that of S. alterniflora marsh (F (1,16)=17.751, P<0.001). The abundance of methanogen in the same vegetation type marsh has vertical variation characteristics at different soil depth. Desulfovibrionales, Desulfobacterales, Syntrophobacterales and Clostridiales were detected at a soil depth of0-30cm in the P. australis marsh, C. malaccensis ma.S. alterniflora marsh. Desulfobacterales was the dominant group at a soil depth of0-30cm in the Min River estuarine marsh. The mam genera of sulfate-reducing bacteria varied from different vegetation types marsh soils. The distribution of sulfate-reducing bacteria communities also presents the vertical change at different soil depth in the same vegetation types marsh. Desulfobacterium and Desulfosarcina were the predominant genera of sulfate-reducing bacteria in the Min River estuarine marsh. The average number of sulfate-reducing bacteria in the P. australis marsh, C. malaccensis marsh, S. alterniflora marsh determined by real-time quantitative PCR technology were8.95×107copies g-1dws,1.55×107copies g-1dws, 2.40×107copies g-1dws, respectively. The average abundance of sulfate-reducing bacteria at a depth of0-30cm in the P. australis marsh was significantly higher than that of C. malaccensis marsh(F (1,16)=26.449, P<0.001), and also significantly higher than that of S. alterniflora marsh (F (1,16)=19.013, P=0.001). The abundance of sulfate-reducing bacteria showed vertical variation characteristics at the different soil depth in same vegetation type marsh zone. It showed that the abundance of methanogens and sulfate-reducing bacteria have a remarkable regression relationship with soil organic carbon content, but no significant correlation with other soil physicochemical factors. The relationship between soil physicochemical factors and community composition of methanogen and sulfate-reducing bacteria were analysised based on RDA and CCA. It showed that the composition of methanogen community and salinity had a highly significant correlation (P=0.002). It also had a significant correlation with pH (P=0.036) and no significant correlation with SOC, TN, SOC/TN (P>0.05). The composition of sulfate-reducing bacteria community had a highly significant correlation with pH (P=0.004). It also had a significant correlation with soil moisture content (P=0.022) and no significant correlation with SMC, SOC, TN, SOC/TN, salinity(P>0.05).The regression analysis showed that the rate of methane production significantly linearly increased with the abundances of both methanogens and sulfate-reducing bacteria for the three vegetation zones together. When regression analysis was carried out for single vegetation zone, methane production rate only significantly linearly increased with the abundance of methanogens in the C. malaccensis marsh(y=0.196x-0.008, R2=0.6671, P=0.007, n=9). The rate of methane production did not correlate with the abundance of sulfate-reducing bacteria in each marsh zone (P>0.05, n=9).更多还原