2019-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/704901摘要：土壤微生物氮循環中的硝化作用與脫硝作用，能排放出如氨氣(NH3)、氧化氮(NO)、二氧化氮(NO2)、亞硝酸氣(HONO)與硝酸氣(HNO3)等大氣光化學反應之氣體。過去研究亦認為這些氣體是造成細懸浮微粒(PM2.5)及臭氧(O3)之重要前驅物。河口與海岸生態系長期以來被認為能提供多樣性的生態系服務功能，如棲地保育、水質淨化、碳氮循環等。然而人為活動從河川上游所排放的大量氮源，使河口附近的海岸濕地其營養鹽增加，更進一步影響海岸濕地的氮循環系統。這樣長期高濃度的氮源輸入下，即可能造成原本海岸濕地土壤氮平衡的改變，並使之成為潛在的光化學氣膠排放來源之一，降低原海岸濕地所具備的生態系服務價值。然而對於海岸濕地氮源的承載力，以及微生物族群變化的調查，目前仍需要更多較具規模的研究。 本項研究主要分為兩大主軸，對於濕地各種氮化物氣體排放與濕地土壤氮源承載力的研究部分，將採集不同地點與植被之海岸濕地土壤，以溫室培養實驗，估算濕地對於硝化作用與脫氮作用的最大承載力。而對於濕地氮化物排放相關的微生物族群，將使用所採集之土壤進行次世代定序與實時螢光定量等分子生物學技術，透過硝化菌功能基因amoA、硝酸菌功能性基因narGHI、亞硝酸菌功能性基因nirS、氧化亞氮產生菌功能性基因nosB及氧化亞氮還原菌功能性基因nosZ進行微生物定量與序列解析，探討台灣海岸濕地土壤中氮化物循環之微生物族群的組成與豐富度，並比較不同環境因子變異可能帶給其族群結構之影響。藉以量化環境因子如何影響土壤氮化物的排放，並提出對未來海岸濕地保育與管理的有效方式，以降低光化學反應氣體排放潛力，並減低其對空氣品質劣化的衝擊。 <br> Abstract: Ammonia (NH3), nitric monoxide (NO), nitric dioxide (NO2), nitrous acid (HONO) and nitric acid (HNO3) are the photochemical reactive nitrogen species that may release from soil during the microbial nitrification and denitrification processes. It is believed that the photochemical reactive nitrogen species are the major photochemical precursors of PM2.5 and ozone in the atmosphere. Coastal wetland is one of the important ecosystems that provides various ecosystem services such as habitat restoration, ecosystem remediation, and carbon sequestration. With the increasing changes of anthropogenic inputs of N from upstream watershed, impacts from climate change and sea water intrusion to the coastal ecosystems, the N cycle related microbial communities can be significantly altered, resulting in alteration of soil N balance. When the N cycle is altered, more photochemical reactive nitrogen species may emit to the atmosphere and reduce the overall ecosystem services of coastal wetlands. However, more studies are needed to comprehensively reveal the impact of soil microbial community structures with the changes of physiochemical factors and N loading. This research will have two aspects. Firstly, the study attempts to evaluate the nitrifying and denitrifying potentials and capacity of different coastal wetland soils through mesocosm studies. This study will also use the real-time quantitative polymerase chain reaction (real-time PCR) and next-generation sequencing (NGS) method of microbial ammonium-oxidizing gene (amoA), nitrate reductase gene (narGHI), nitrite reductase gene (nirS), nitric oxide reductase gene (norB) and nitrous oxide gene (nosZ) to better understand the compositions of soil microbial communities that are responsible to nitrification and denitrification processes in coastal wetlands. We will also analyze the molecular variances among communities and clarify the effects of different environmental factors on their community structures. With the knowledge of the relation among environmental factors and soil microbial community structures, we shall be able to provide best management practices for coastal wetland protection and restoration to minimize the emissions of photochemical reactive nitrogen species.海岸濕地光化學反應氮化物土壤微生物細懸浮微粒coastal wetlandphotochemical reactive nitrogensoil microbial communityPM2.5