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温度变化下底栖动物扰动对挠力河湿地沉积物中氨氧化微生物群落的影响

Effects of benthic animal disturbance on ammonia-oxidising microbial communities in sediments of Naoli River Wetland under varying temperatures

  • 摘要: 为探究不同温度条件下底栖动物扰动对湿地沉积物中氨氧化微生物群落的影响,本研究选取羽摇蚊(Chironomus plumosus)、霍甫水丝蚓(Limnodrilus hoffmeisteri)和椭圆萝卜螺(Radix swinhoei)3种常见底栖动物,构建室内–水体微宇宙模拟体系,设置22 ℃(高温)与15 ℃(低温)两个温度梯度,结合高通量测序与实时荧光定量PCR技术,比较不同处理下氨氧化古菌(ammonia-oxidizing archaea, AOA)和氨氧化细菌(ammonia-oxidizing bacteria, AOB)群落结构和丰度的差异。结果表明,在高温和低温条件下霍甫水丝蚓均显著增加了沉积物中总碳(TC)、总氮(TN)、硝态氮(NO3)和铵态氮(NH4+)含量,同时显著降低了碳氮比(C/N)和亚硝态氮(NO2)含量(p<0.05)。相比之下,羽摇蚊和椭圆萝卜螺对沉积物理化性质的影响相对较弱或不显著。AOA和AOB的amoA基因丰度在不同处理间差异显著,整体上AOA的amoA基因丰度高于AOB。羽摇蚊和霍甫水丝蚓显著降低了AOB基因丰度,而椭圆萝卜螺的影响相对较弱。群落多样性分析显示,不同处理对AOA和AOB群落多样性产生了差异效应,在高温条件下羽摇蚊和霍甫水丝蚓提升了AOB群落多样性。PCoA分析和群落组成分析显示,在高温和低温条件下霍甫水丝蚓均改变了AOA和AOB群落结构。群落组成分析显示,AOA群落在高温和低温条件下均表现为亚硝化宇宙菌属( Candidatus_Nitrososphaera)相对丰度降低,而AOB群落则在高温条件下以亚硝化单胞菌属(Nitrosomonas)相对丰度的增加为特征。冗余分析与相关分析显示,TN、TC、NH4+和C/N是影响氨氧化微生物群落结构的主要环境因子,其中AOB丰度与NH4+呈显著正相关,与TC、TN和NO3呈显著负相关(p<0.05)。综上所述,不同温度条件下底栖动物扰动对湿地沉积物中氨氧化微生物群落结构和丰度的影响具有显著差异。

     

    Abstract: To investigate the effects of benthic faunal disturbance on ammonia-oxidizing microbial communities in wetland sediments under different temperature conditions, three common benthic fauna species, Chironomus plumosus, Limnodrilus hoffmeisteri, and Radix swinhoei, were selected to establish an indoor aquatic microcosm system under two temperature regimes: 22 ℃ (high temperature) and 15 ℃ (low temperature). High-throughput sequencing and real-time quantitative PCR (qPCR) were employed to compare the community structure and abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) among different treatments. The results showed that L. hoffmeisteri significantly increased total carbon (TC), total nitrogen (TN), nitrate nitrogen (NO3), and ammonium nitrogen (NH4+) contents in sediments under both temperature conditions, while significantly decreasing the carbon-to-nitrogen ratio (C/N) and nitrite nitrogen (NO2) content (p<0.05). In contrast, the effects of C. plumosus and R. swinhoei on sediment physicochemical properties were relatively weak or insignificant. Significant differences in amoA gene abundance of AOA and AOB were observed among treatments, with AOA abundance generally exceeding that of AOB. Treatments with C. plumosus and L. hoffmeisteri significantly reduced AOB gene abundance, whereas R. swinhoei exerted comparatively weaker effects. Community diversity analysis demonstrated that different treatments exerted distinct effects on AOA and AOB diversity, and under high-temperature conditions, C. plumosus and L. hoffmeisteri significantly enhanced AOB community diversity. Principal coordinate analysis and community composition analysis further revealed that L. hoffmeisteri markedly altered both AOA and AOB community structures under high- and low-temperature conditions. Specifically, AOA communities were characterized by a reduction in Candidatus Nitrososphaera under both temperature conditions, whereas AOB communities showed an increased relative abundance of Nitrosomonas under high-temperature conditions. Redundancy analysis and correlation analysis indicated that TN, TC, NH4+, and C/N were the major environmental factors influencing ammonia-oxidizing microbial community structure. In particular, AOB abundance was significantly positively correlated with NH4+ and significantly negatively correlated with TC, TN, and NO3 (p<0.05). Overall, benthic faunal disturbance exerted significantly different effects on the community structure and abundance of ammonia-oxidizing microorganisms in wetland sediments under different temperature conditions.

     

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