Bernhard Anne E, Dwyer Courtney, Idrizi Adrian, Bender Geoffrey, Zwick Rachel
Biology Department, Connecticut College, New London, CT USA.
Front Microbiol. 2015 Feb 4;6:46. doi: 10.3389/fmicb.2015.00046. eCollection 2015.
Recent studies on the impacts of disturbance on microbial communities indicate communities show differential responses to disturbance, yet our understanding of how different microbial communities may respond to and recover from disturbance is still rudimentary. We investigated impacts of tidal restriction followed by tidal restoration on abundance and diversity of denitrifying bacteria, ammonia-oxidizing bacteria (AOB), and ammonia-oxidizing archaea (AOA) in New England salt marshes by analyzing nirS and bacterial and archaeal amoA genes, respectively. TRFLP analysis of nirS and betaproteobacterial amoA genes revealed significant differences between restored and undisturbed marshes, with the greatest differences detected in deeper sediments. Additionally, community patterns indicated a potential recovery trajectory for denitrifiers. Analysis of archaeal amoA genes, however, revealed no differences in community composition between restored and undisturbed marshes, but we detected significantly higher gene abundance in deeper sediment at restored sites. Abundances of nirS and betaproteobacterial amoA genes were also significantly greater in deeper sediments at restored sites. Porewater ammonium was significantly higher at depth in restored sediments compared to undisturbed sediments, suggesting a possible mechanism driving some of the community differences. Our results suggest that impacts of disturbance on denitrifying and ammonia-oxidizing communities remain nearly 30 years after restoration, potentially impacting nitrogen-cycling processes in the marsh. We also present data suggesting that sampling deeper in sediments may be critical for detecting disturbance effects in coastal sediments.
近期关于干扰对微生物群落影响的研究表明，不同群落对干扰的反应存在差异，但我们对于不同微生物群落如何对干扰做出反应以及从干扰中恢复的理解仍很初步。我们通过分别分析nirS基因以及细菌和古菌的amoA基因，研究了潮汐限制后再进行潮汐恢复对新英格兰盐沼中反硝化细菌、氨氧化细菌（AOB）和氨氧化古菌（AOA）的丰度和多样性的影响。对nirS基因和β-变形菌amoA基因的末端限制性片段长度多态性（TRFLP）分析显示，恢复后的盐沼与未受干扰的盐沼之间存在显著差异，在较深沉积物中检测到的差异最大。此外，群落模式表明反硝化菌存在潜在的恢复轨迹。然而，对古菌amoA基因的分析显示，恢复后的盐沼与未受干扰的盐沼之间群落组成没有差异，但我们在恢复地点较深的沉积物中检测到基因丰度显著更高。恢复地点较深沉积物中nirS基因和β-变形菌amoA基因的丰度也显著更高。与未受干扰的沉积物相比，恢复后的沉积物深处孔隙水中的铵含量显著更高，这表明可能存在一种驱动部分群落差异的机制。我们的结果表明，恢复近30年后，干扰对反硝化和氨氧化群落的影响依然存在，可能会影响盐沼中的氮循环过程。我们还提供了数据表明，在沉积物中更深层采样对于检测沿海沉积物中的干扰效应可能至关重要。
