互花米草入侵对滨海湿地甲烷厌氧氧化及其微生物机制影响研究

项目名称： 互花米草入侵对滨海湿地甲烷厌氧氧化及其微生物机制影响研究

项目编号： No.41501274

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 地质学

项目作者： 袁俊吉

作者单位： 中国科学院南京土壤研究所

项目金额： 20万元

中文摘要： 甲烷厌氧氧化是消减海洋甲烷排放的主要过程。互花米草入侵明显提高了滨海湿地甲烷排放，但排放量仍显著低于淡水湿地，产生的甲烷可能被厌氧氧化所消耗。那么，互花米草如何影响湿地甲烷厌氧氧化速率，微生物机制如何，尚不清楚。项目拟选取江苏大丰滨海湿地，采集互花米草、盐蒿、芦苇、光滩和开放水面湿地土壤，研究甲烷产生和厌氧氧化潜力及电子受体含量，阐明湿地甲烷厌氧氧化速率和互花米草入侵的影响效应，解析甲烷厌氧氧化的关键控制因素；采用13C示踪和稳定性同位素核酸探针(DNA-SIP)等技术，研究甲烷厌氧氧化菌数量和群落结构，阐明不同湿地甲烷厌氧氧化功能菌特征和互花米草入侵诱导的功能菌演替规律；利用酶联荧光原位杂交(CARD-FISH)技术，研究湿地甲烷厌氧氧化功能菌的原位分布特征及共生微生物种类和数量，解析甲烷厌氧氧化耦联代谢途径和互花米草入侵的影响机制，为评估互花米草入侵对滨海湿地甲烷排放影响提供科学依据。

中文关键词： 全球变化；甲烷；甲烷氧化菌；生物入侵；滨海湿地

英文摘要： Anaerobic oxidation of methane (AOM) efficiently controls the CH4 emissions from the ocean, because almost all the CH4 produced in ocean sediments is consumed by AOM within the sulfate-penetrated seafloor zones. The invasion of exotic Spartina alterniflora has significantly increased CH4 emission from Chinese coastal wetlands. However, the emission rates are extremely lower than those from freshwater wetlands. The produced CH4 might be consumed by AOM process. However, there are still debates about the influence of S. alterniflora on AOM rates, and what is the microbiological mechanism for this important biochemical process controlling CH4 emissions. In this study, soil and porewater samples will be collected from open water, bare tidal flat, and invasive S. alterniflora, native Suaeda salsa, and Phragmites australis marshes. To understand the AOM rates in the coastal wetland and the their key affecting factors, anaerobic CH4 oxidation potential, CH4 production potential, concentrations of CH4 and electron acceptors (e.g. SO42-, NO2-, NO3-, Fe3+, MnO4-, et al.) will be analyzed. Laboratory incubation experiments, by using 13C isotope trace technique and molecular biotechnology such as DNA-SIP, will be carried out to investigate the association of AOM rates with the functional or community structure of the anaerobic methanotrophic archaea (ANME). The metabolic pathway of the functional ANME will explored by in situ identification of the ANME and their physically associated microorganisms by using the catalyzed reporter deposition fluorescent in situ hybridization (CARD-FISH). The objectives of this study are (1) to reveal the AOM rates in coastal wetlands and the implication to CH4 emissions, and (2) to gain a mechanistic understanding of invasive S. alterniflora on AOM process. This study will be exposed to provide scientific evidence for evaluation the impacts of S. alterniflora on CH4 emissions from coastal wetlands of China.

英文关键词： global change;methane;methane-oxidizing bacteria;biological invasion;coastal wetland