Relationships among Typha Biomass, Pore Water Methane, and Reflectance in a Delaware (U.S.A.) Brackish Marsh
Relationships among Typha Biomass, Pore Water Methane, and Reflectance in a Delaware (U.S.A.) Brackish Marsh
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美国特拉华州咸水沼泽香蒲生物量、孔隙水甲烷和反射率之间的关系
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发表时间：
1993
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通讯作者：
V. Klemas
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作者：
M. F. Gross;M. Hardisky;P. L. Wolf;V. Klemas
甲烷是湿地土壤中产生的一种“温室效应”气体，但控制其产生和排放的因素尚不清楚。通常，甲烷孔隙水浓度和大气通量呈正相关。如果湿地植物生物量、反射率和甲烷浓度或通量之间存在相关性，就有可能利用遥感技术研究全球甲烷循环。我们的研究有两个目的：（1）确定遥感是否可以用于估计一个特拉华州（美国）的香蒲植物生物量。半咸水沼泽，和（2）以确定香蒲植物的影响溶解孔隙水甲烷浓度在整个一年。冠层反射率与地上生物量相关（r = 0.887），与地下生物量相关（r = 0.809）。溶解孔隙水甲烷浓度普遍低于植被比在unvegetated地区。仅在有植被的地区，沉积物顶部10厘米处的浓度远低于更深处的浓度。由于超过60%的活根/根茎生物量是在顶部10厘米，这是可能的充氧根际和甲烷运输通过根保持甲烷浓度低的土壤表面附近。在10-20 cm深度处甲烷的大量生长季节增加，其中剩余的活组织，表明释放足够的产甲烷底物，导致甲烷产量超过甲烷排放/氧化。总体而言，甲烷浓度在冬季减少，在晚春增加，但滞后的变化，土壤温度和活的气生生物量的两个月，并没有显着相关的基板盐度。由于遥感可以用来估计香蒲生物量，由于活根生物量影响沉积甲烷水库，它可能是间接估计甲烷浓度的基础上遥感测量。
Methane is a "greenhouse effect" gas produced in wetland soils, yet factors controlling its production and emission are not well understood. Often, methane pore water concentration and atmospheric flux are positively correlated. If correlations can be found among wetland plant biomass, reflectance, and methane concentrations or flux, it may be possible to study the global methane cycle using remote sensing. Our study had two objectives: (1) to determine if remote sensing could be used to estimate biomass of Typha angustifolia plants in a Delaware (U.S.A.) brackish marsh, and (2) to determine if Typha plants influence dissolved pore water methane concentrations throughout a year. Canopy reflectance was correlated (r = 0.887) with live aerial biomass, which was correlated with live belowground biomass (r = 0.809). Dissolved pore water methane concentrations were generally lower in vegetated than in unvegetated areas. In vegetated areas only, concentrations were much lower in the top 10 cm of sediments than at greater depths. Since over 60% of the live root/rhizome biomass is in the top 10 cm, it is likely that an oxygenated rhizosphere and methane transport through roots kept the methane concentration low near the soil surface. Substantial growing season increases in methane at depths of 10-20 cm, where the remaining live tissue is, suggest the release of enough methanogenic substrates to cause methane production to exceed methane emission/oxidation. Overall, methane concentrations diminished in winter and increased in late spring, but lagged changes in soil temperature and in live aerial biomass by two months, and were not significantly correlated with substrate salinity. Since remote sensing can be used to estimate Typha biomass, and since live root biomass influences the sedimentary methane reservoir, it might be possible to estimate methane concentrations indirectly based on remote sensing measurements.