School of Civil and Environmental Engineering, Yonsei University, Seoul, 120-749, South Korea.
Smithsonian Environmental Research Center, Washington, DC, 20013, USA.
Microb Ecol. 2017 Oct;74(3):670-680. doi: 10.1007/s00248-017-0960-8. Epub 2017 Mar 22.
Salt marshes are unique ecosystem of which a microbial community is expected to be affected by global climate change. In this study, by using T-RFLP analysis, quantitative PCR, and pyrosequencing, we comprehensively analyzed the microbial community structure responding to elevated CO (eCO) and N addition in a salt marsh ecosystem subjected to CO manipulation and N addition for about 3 years. We focused on the genes of microbes relevant to N-cycling (denitrification and nitrification), CH-flux (methanogens and methanotrophs), and S-cycling (sulfate reduction) considering that they are key functional groups involved in the nutrient cycle of salt marsh system. Overall, this study suggests that (1) eCO and N addition affect functional microbial community involved in greenhouse gas flux in salt marsh system. Specifically, the denitrification process may be facilitated, while the methanogenesis may be impeded due to the outcompeting of sulfate reduction by eCO and N. This implies that future global change may cause a probable change in GHGs flux and positive feedback to global climate change in salt marsh; (2) the effect of eCO and N on functional group seems specific and to contrast with each other, but the effect of single factor would not be compromised but complemented by combination of two factors. (3) The response of functional groups to eCO and/or N may be directly or indirectly related to the plant community and its response to eCO and/or N. This study provides new insights into our understanding of functional microbial community responses to eCO and/or N addition in a C3/C4 plant mixed salt marsh system.
盐沼是一种独特的生态系统，其中微生物群落预计会受到全球气候变化的影响。在这项研究中，我们通过使用 T-RFLP 分析、定量 PCR 和焦磷酸测序，全面分析了在一个盐沼生态系统中，微生物群落结构对 CO 操纵和 N 添加的响应，该生态系统已经接受 CO 处理和 N 添加约 3 年。我们专注于与 N 循环（反硝化和硝化）、CH 通量（产甲烷菌和甲烷氧化菌）和 S 循环（硫酸盐还原）相关的微生物基因，因为它们是参与盐沼系统养分循环的关键功能群。总的来说，这项研究表明：（1）eCO 和 N 添加会影响参与盐沼系统温室气体通量的功能微生物群落。具体而言，反硝化过程可能会得到促进，而由于 eCO 和 N 的硫酸盐还原竞争，甲烷生成可能会受到阻碍。这意味着未来的全球变化可能会导致盐沼中 GHGs 通量发生变化，并对全球气候变化产生正反馈；（2）eCO 和 N 对功能群的影响似乎是特定的，并且相互对比，但单一因素的影响不会因两种因素的结合而受到损害，而是会得到补充；（3）功能群对 eCO 和/或 N 的响应可能与植物群落及其对 eCO 和/或 N 的响应直接或间接相关。本研究为我们理解 C3/C4 植物混合盐沼系统中功能微生物群落对 eCO 和/或 N 添加的响应提供了新的认识。
