Carbon dioxide fluxes reflect plant zonation and belowground biomass in a coastal marsh
Carbon dioxide fluxes reflect plant zonation and belowground biomass in a coastal marsh
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DOI：
10.1002/ecs2.1560
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发表时间：
2016-11-01
期刊：
影响因子：
2.7
通讯作者：
Kroeger, Kevin D.
中科院分区：
文献类型：
--
作者：
Moseman-Valtierra, Serena;Abdul-Aziz, Omar I.;Kroeger, Kevin D.
沿海湿地是全球主要的碳汇，但它们是异质的和动态的生态系统。为了表征空间和时间的变化，在新英格兰盐沼，温室气体（GHG）通量之间的主要植物定义的区域在生长季节进行了比较。在夏季（2012-2014年），包括低沼泽（互花米草），高沼泽（Distichlis spicata和灯心草为主），入侵芦苇区，和无植被池塘的两个测定实验中，比较了二氧化碳（CO2）和甲烷（CH 4）通量。白天和夜间通量也对比在本地沼泽区。N2 O通量平行测量CO2和CH 4通量，但没有发现是显着的。要测试的关系，CO2和CH 4通量与几个本地植物指标，一个多变量非线性模型。入侵的芦苇带（-7 ~-15 μ molCO_2·m（-2）·s（-1））和S.互花米草低沼泽区（最高可达-14 μ molCO_2.m（-2）·s（-1））表现出最高的平均CO_2吸收速率，而天然高沼泽区（低于-2 μ molCO_2.m（-2）·s（-1））的平均CO_2吸收速率要低得多。无植被的池塘通常是大气中少量CO2的来源（< 0.5 μ mol CO2·m（-2）·s（-1））。夜间排放的CO2平均只有35%的白天吸收在低沼泽区，但他们超过白天的CO2吸收高达三倍，在本地高沼泽区。基于建模，地下生物量是植物度量最强烈的相关性与CO2通量在本地沼泽区，而没有植物变量相关显着与CH 4通量。甲烷通量没有变化，白天和黑夜之间，并没有显着抵消CO2吸收在任何植被沼泽区的基础上持续的全球变暖潜势计算。这些研究结果表明，注意空间分区以及扩大测量和建模的温室气体排放量在更大的时间尺度将有助于提高沿海沼泽地的碳核算的准确性。
Coastal wetlands are major global carbon sinks; however, they are heterogeneous and dynamic ecosystems. To characterize spatial and temporal variability in a New England salt marsh, greenhouse gas (GHG) fluxes were compared among major plant-defined zones during growing seasons. Carbon dioxide (CO2) and methane (CH4) fluxes were compared in two mensurative experiments during summer months (2012-2014) that included low marsh (Spartina alterniflora), high marsh (Distichlis spicata and Juncus gerardii-dominated), invasive Phragmites australis zones, and unvegetated ponds. Day-and nighttime fluxes were also contrasted in the native marsh zones. N2O fluxes were measured in parallel with CO2 and CH4 fluxes, but were not found to be significant. To test the relationships of CO2 and CH4 fluxes with several native plant metrics, a multivariate nonlinear model was used. Invasive P. australis zones (-7 to -15 mu mol CO2.m(-2).s(-1)) and S. alterniflora low marsh zones (up to -14 mu mol CO2.m(-2).s(-1)) displayed highest average CO2 -uptake rates, while those in the native high marsh zone (less than -2 mu mol CO2.m(-2).s(-1)) were much lower. Unvegetated ponds were typically small sources of CO2 to the atmosphere (< 0.5 mu mol CO2.m(-2).s(-1)). Night-time emissions of CO2 averaged only 35% of daytime uptake in the low marsh zone, but they exceeded daytime CO2 uptake by up to threefold in the native high marsh zone. Based on modeling, belowground biomass was the plant metric most strongly correlated with CO2 fluxes in native marsh zones, while none of the plant variables correlated significantly with CH4 fluxes. Methane fluxes did not vary between day and night and did not significantly offset CO2 uptake in any vegetated marsh zones based on sustained global warming potential calculations. These findings suggest that attention to spatial zonation as well as expanded measurements and modeling of GHG emissions across greater temporal scales will help to improve accuracy of carbon accounting in coastal marshes.