| 长江口盐沼硫酸盐还原菌的分布特征与环境机制 |
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| 引用本文： | 陈庆强,唐媛,杨艳,谢冰,吕宝一.长江口盐沼硫酸盐还原菌的分布特征与环境机制[J].沉积学报,2012,30(6):1088-1098. |
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| 作者姓名： | 陈庆强 唐媛 杨艳 谢冰 吕宝一 |
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| 作者单位： | 1. 华东师范大学河口海岸学国家重点实验室,上海,200062
2. 华东师范大学环境科学系,上海,200062 |
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| 摘 要： | 选择长江口崇明东滩两类植被区（互花米草、土著植被）纵向剖面，根据不同高程部位柱样土壤和植被根际硫酸盐还原菌（SRB）与异养菌的数量，颗粒有机碳（POC）含量与δ13C值，孔隙水Cl-/SO2- ４摩尔比等，研究盐沼SRB的空间分布特征与机制。自高潮滩向光滩，柱样氧含量降低，SO2- ４含量增加，导致SRB含量增加，SRB在有机质矿化中的作用增强。高潮滩柱样不同深度层位的异养菌数量明显大于中潮滩和光滩柱样的相应层位，这与由陆向海柱样氧含量及POC含量降低有关。SRB对植被根际环境的变化较敏感，芦苇根际最有利于SRB生长，藨草根际次之；互花米草根际不利于SRB生长，根系分泌物可能对SRB有抑制作用。土壤有机质含量是导致不同纵向剖面相同高程部位柱样之间微生物数量差异的主要因素。同一纵向剖面不同高程部位柱样之间在土壤氧含量与SO2- ４含量方面的不同，导致这些柱样微生物数量存在差异。盐沼柱样孔隙水Cl-/SO2-４摩尔比总体偏低，多小于19.33，指示有非海源SO2- ４加入。非海源SO2-４的加入掩盖了硫酸盐还原作用对SO2-４的消耗，增加了利用孔隙水Cl-/SO2-４摩尔比定量研究盐沼硫酸盐还原作用强度的难度。柱样中SRB越多，Cl-/SO2-４摩尔比就越大，硫酸盐还原作用就越明显。
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| 关 键 词： | 盐沼 硫酸盐还原菌 异养菌 长江口 |
Distribution Pattern of Sulfate-reducing Bacteria and Its Environmental Mechanism in the Saltmarsh of the Yangtze Estuary |
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| Institution: | CHEN Qing-qiang1 TANG Yuan2 YANG Yan1 XIE Bing2 Lü Bao-yi2(1.State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200062; 2.Department of Environment Science,East China Normal University,Shanghai 200062) |
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| Abstract: | Coastal saltmarshes are among the most productive ecosystems in the world, and scientific evaluations of their potentials as carbon sources or sinks have great significances for the studies on carbon exchanges between land and the sea. Sulfate reduction is the most important process for degradation of soil organic matters of saltmarshes, and the main functional microbes in this process are sulfate reducing bacteria. Two transects from hight tidal flat to bare flat were selected from areas with Spartina alterniflora and native vegetation, respectively, for investigations of spatial distribution characteristics and mechanism of sulfate reducing bacteria (SRB) in the Chongmingdongtan saltmarsh of the Yangtze Estuary. This study was based on data including concentrations of both SRB and heterotrophic bacteria (HB) in soil samples with different depths and plant rhizospheres, content and δ13C value of particulate organic carbon (POC), and molar ratio of Cl /SO2-4 of interstitial water in drilling cores with different altitudes in the saltmarsh. SRB concentrations of the cores increase from the high tidal flat to the bare flat, due to decrease of oxygen content and increase of SO2-4 content of the cores from land to the sea. This suggests that SRB turn to be more important in mineralization of organic matters from the high tidal flat to the bare flat. The variation trend of SRB concentration from the high tidal flat to the bare flat, however, has not been influenced markedly by POC content of the soils. The concentrations of HB in samples with different depths of the drilling core from high tidal flat are markedly greater than those of HB in samples with corresponding depths of the drilling cores from both middle tidal flat and bare flat. This is due to the decreases in both oxygen content and POC content of the cores from land to the sea. Different cores are similar in that the concentrations of HB decrease with depth due to the decrease of soil oxygen content with depth. The concentration of HB in the area with higher POC content is markedly greater that that of HB in the area with lower POC content. The concentrations of SRB are markedly different in rhizospheres of different types of vegetations. SRB is susceptible to rhizospheres of different types of vegetations. Rehizosphere of Phraqmites australis is the most favorable one for SRB growth, and that of Scirpus triqueter comes next. Rehizosphere of Spartina alterniflora is unfavorable to SRB growth, and the root secretion may restrain the development of SRB. The concentration of HB in the rhizosphere soil is greater than that of HB in nonrhizosphere soil, and HB is not susceptible to the rhizospheres of different types of vegetations. Soil organic matter content is the key factor that result in the difference in microbe amount between the drilling cores with the same altitudes from different transects. The difference in microbe amount between drilling cores with different altitudes in one transect, is due to the differences in both soil oxygen content and SO2-4 content between the cores. SRB is susceptible to the organic components originating from Spartina alterniflora, and the organic matters with much components coming from Spartina alterniflora may restrain the growth of SRB. Mineralizations of the organic components originating from Spartina alterniflora probably attribute to HB. The molar ratio of Cl /SO2-4 of interstitial water is low, and is less than 19.33 in most cases, indicating additon of SO2-4 with sources other than the sea. Such additions of SO2-4 offset the consumption of SO2-4 due to sulfate reduction, and make it more difficult to determine quantitatively the intensity of sulfate reduction based on the molar ratio of Cl /SO2-4 of interstitial water in the salt marsh. The more SRB there exists, the greater the molar ratio of Cl /SO2-4 is, and the more marked sulfate reduction is in one drilling core. |
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| Keywords: | sahmarsh sulfate-reducing bacteria heterotrophic bacteria the Yangtze Estuary |
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