| 摘要: | 本研究以紅樹林的淨初級生產量、溫室氣體，包含CH4、N2O、CO2年釋放通量、碳儲存量等因素，藉由碳質量收支計算法，估計濕地的碳吸存能力。為達到研究目的，本研究於2010年9月到2012年3月在台灣七股鹽田紅樹林濕地，分別收集水質、土壤、紅樹林灌木的落葉量及樹木胸徑、淨初級生產量、甲烷（CH4）釋放通量、氧化亞氮（N2O）釋放通量、二氧化碳（CO2）釋放通量。
依據資料分析結果，紅樹林濕地所監測到甲烷（CH4）在透光環境的釋放通量介於-0.43~5.44 mg CH4-C m-2 h-1；不透光環境的釋放通量介於-0.4~0.48 mg CH4-C m-2 h-1。氧化亞氮（N2O）在透光環境的釋放通量介於-85.34~173.23μg N2O m-2 h-1；不透光環境的釋放通量介於-27.44~177.73μg N2O m-2 h-1。二氧化碳（CO2）在透光環境的釋放通量介於-97.34~40.21 mg CO2-C m-2 h-1；不透光環境的釋放通量介於5.04~97.84 mg CO2-C m-2 h-1。依上述資料估算出，七股紅樹林濕地CH4及N2O的年釋放通量分別為3 g CH4-C m-2 yr-1、149 mg N2O m-2 yr-1。同時，紅樹林的總呼吸通量(CO2)為246.74 g CO2-C m-2 yr-1，異營性呼吸通量為148 g C m-2 yr-1。
在紅樹林淨初級生產量（FNPP）估計上，依據胸徑推估法，FNPP為632( 273~1036 ) g C m-2 yr-1；依據係數估算法，FNPP為913( 820~1067 ) g C m-2 yr-1。因此，本研究認為七股紅樹林每年淨初級生產量(FNPP)為632~913 g C m-2 yr-1。在濕地碳吸存通量上，本研究發現七股紅樹林濕地碳吸存通量結果為462~749 g C m-2 yr-1，與國外文獻之相對數值561~1,170 g C m-2 yr-1相似。
本研究利用紅樹林地面上(AGA)和地面下生物量(BGB)所得總生物量平均、紅樹林植物的生物量含碳比率(Cfm)及每株紅樹林植物所佔面積( )為參數，計算出單位面積紅樹林生物碳密度平均為3,299 g C m2。因紅樹林總面積57,220.6 m2，故紅樹林總生物碳儲存量為189 ton C。在有機碳密度估量上，藉由土壤有機碳密度(SCD)方法，本研究估計有機碳密度平均為2,485 g C m2，紅樹林總土壤有機碳儲存量為142 ton C。
The purpose of this study was to estimate the carbon sequestration of wetlands using the parameters of the Net Primary Production, the yearly emission of greenhouse gases containing CH4, N2O, and CO2, and the carbon storage of mangrove forests through the carbon budget calculation method. To address the purpose, this study collected the data of the water quality, soil, the quantity of dead leaves, and the diameter at breast height of mangrove forest, Net Primary Production, CH4 emission, N2O emission, and CO2 emission at Chigu mangrove forests wetland, Taiwan, from September, 2010 to March, 2012.
Based on the collected data, it was found that at Chigu mangrove forests wetland, the CH4 emission in a translucent environment and an opaque environment were from -0.43 to 5.44 mg CH4-C m-2 h-1 and from -0.4 to 0.48 mg CH4-C m-2 h-1, respectively. The N2O emission in a translucent environment and in an opaque environment were from -85.34 to 173.23μg N2O m-2 h-1and from -27.44 to 177.73μg N2O m-2 h-1, respectively. The CO2 emission in a translucent environment and an opaque environment were from -97.34 to 40.21 mg CO2-C m-2 h-1 and from 5.04 to 97.84 mg CO2-C m-2 h-1, respectively. Based on the results, this study estimated that the yearly emissions of CH4 and N2O were 3 g CH4-C m-2 yr-1 and 149 mg N2O m-2 yr-1, respectively. The total ecosystem respiration and the heterotrophic respiration of the mangrove forests were 246.74 g CO2-C m-2 yr-1 and 148 g C m-2 yr-1, respectively.
Based on the Diameter at Breast Height (DBH) FNPP and the coefficient estimation methods, the Net Primary Productivity (FNPP) were calculated to be 632 g C m-2 yr-1 and 913 g C m-2 yr-1, respectively. This study argued that the FNPP of Chigu mangrove forests wetland was from 462 to 749 g C m-2 yr-1 and was similar to the results of 561 to 1,170 g C m-2 yr-1 reported in the research literature.
Based on the average of the total above-ground biomass and the total below-ground biomass, the Cfm, and the average area that a mangrove plant covers ( ), this study argued that the carbon density of Chigu mangrove forests wetland was 3,299 g C m2. The area of Chigu mangrove forests wetland is 57,220.6m2, and so the total of Soil Organic Matter Pool is 189 ton C. Using the Soil Organic Carbon Density calculation method, this study also argued that the average Soil Organic Carbon Density of Chigu mangrove forests wetland was 2,485 g C m2, and the total Soil Organic Carbon Density was 142 ton C. |
