Ecological Agriculture: Nature-Based Solutions for Restoring Wetland Carbon Sink under Climate Change【Department of Life Sciences / Lin, Hsing-Juh / Distinguished Professor】
生態農業：氣候變遷下以自然為本之濕地碳匯復育策略【生命科學系/林幸助特聘教授】
論文篇名 英文：Flushing emissions of methane and carbon dioxide from mangrove soils during tidal cycles
中文：紅樹林土壤甲烷及二氧化碳隨潮汐循環的瞬間湧出
期刊名稱 Science of the Total Environment
發表年份,卷數,起迄頁數 2024, 919: 170768
作者 Lin, Chiao-Wen; Lin, Wei-Jen; Ho, Chuan-Wen; Kao, Yu-Chen; Yong, Zhao-Jun; Lin, Hsing-Juh(林幸助)*
DOI 10.1016/j.scitotenv.2024.170768
中文摘要 紅樹林是連接陸地、淡水和海洋的過渡區，大量的有機碳在土壤中積累，形成相當大的碳匯。然而，土壤也可能是溫室氣體 （GHG） 排放的來源。本研究假設僅在退潮期間測量溫室氣體排放可以代表紅樹林的晝夜溫室氣體排放。在夏季和秋季，使用超便攜氣體分析儀對 Kandelia obovata（無呼吸根）和 Avicennia marina（有呼吸根）紅樹林中的甲烷 （CH4） 和二氧化碳 （CO2） 排放進行量化。該分析儀連接到不鏽鋼框架上的封閉罩，在退潮時插入 10 釐米深的紅樹林土壤中，在漲潮時利用浮動罩，每 20 秒進行一次測量，持續 7 分鐘，每次測量之間暫停 3 分鐘。這個週期重複了 6 小時，涵蓋了從退潮到漲潮再回到下一個退潮的完整潮汐週期。結果顯示，CH4 通量在潮汐週期中變化很大，K. obovata 的通量從 -1.25 到 96.24 μmol CH4 m-2 h-1，A. marina 從 2.86 到 2662.00 μmol CH4 m-2 h-1。K. obovata 的 CO2 通量範圍為 -4.23 至 20.65 mmol CO2 m-2 h-1，A. marina 的 CO2 通量範圍為 0.09 至 24.69 mmol CO2 m-2 h-1。紅樹林中 GHG 排放的晝夜變化主要由潮汐周期驅動。CH4 和 CO2 的峰值排放是在漲潮開始時觀察到的，而不是在白天或夜間。雖然 K. obovata 和 A. marina 紅樹林在潮汐週期期間的 CO2 通量模式相似，但它們在潮汐週期中的 CH4 通量模式不同。可能是由於不同的運輸機制，CO2 排放主要受表層土壤的影響，而 CH4 主要來自較深的土壤，因此受到根系結構的影響。為了減少在潮汐迴圈期間測量紅樹林土壤溫室氣體排放的不確定性，建議在洪水和退潮開始前後 30 分鐘內增加溫室氣體通量測量的數量。
英文摘要 Mangroves are transition areas connecting land, freshwater, and the ocean, where a great amount of organic carbon accumulates in the soil, forming a considerable carbon sink. However, the soil might also be a source of greenhouse gas (GHG) emissions. This study hypothesized that measuring GHG emissions solely during low tides can represent diurnal GHG emissions in mangroves. Methane (CH4) and carbon dioxide (CO2) emissions were quantified using an ultraportable gas analyzer in Kandelia obovata (without pneumatophores) and Avicennia marina (with pneumatophores) mangroves in summer and fall. The analyzer, connected to a closed chamber on a stainless-steel frame, was inserted into 10 cm-depth mangrove soils during low tides and utilized a floating chamber during high tides. Measurements were taken every 20 seconds for 7 minutes, with a 3-minute pause between each measurement. This cycle repeated for 6 hours, covering a full tidal cycle from low tide to high tide and back to the next low tide. The results showed that the CH4 fluxes varied greatly during tidal cycles, from -1.25 to 96.24 µmol CH4 m−2 h−1 for K. obovata and from 2.86 to 2662.00 µmol CH4 m−2 h−1 for A. marina. The CO2 fluxes ranged from -4.23 to 20.65 mmol CO2 m−2 h−1 for K. obovata and from 0.09 to 24.69 mmol CO2 m−2 h−1 for A. marina. The diurnal variation in GHG levels in mangroves is predominantly driven by tidal cycles. The peak emissions of CH4 and CO2 were noted at the beginning of the flooding tide, rather than during daytime or nighttime. While the patterns of the CO2 fluxes during tidal cycles were similar between K. obovata and A. marina mangroves, their CH4 flux patterns during the tidal cycles differed. Possibly due to different transport mechanisms, CO2 emissions are primarily influenced by surface soils, whereas CH4 is predominantly emitted from deeper soils, thus being influenced by root structures. To reduce the uncertainty in measuring GHG emissions in mangrove soils during a tidal cycle, it is advisable to increase the number of GHG flux measurements during the period spanning 30 minutes before and after the beginning of the flooding and ebbing tides.
發表成果與本中心研究主題相關性 紅樹林碳匯之估算