Soil water content drives spatiotemporal patterns of CO 2 and N 2 O emissions from a Mediterranean riparian forest soil
Soil water content drives spatiotemporal patterns of CO 2 and N 2 O emissions from a Mediterranean riparian forest soil
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DOI：
10.5194/bg-14-4195-2017
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发表时间：
2017-09
期刊：
影响因子：
4.9
通讯作者：
Sílvia Poblador;A. Lupon;S. Sabaté;F. Sabater
中科院分区：
文献类型：
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作者：
Sílvia Poblador;A. Lupon;S. Sabaté;F. Sabater
抽象。河岸带在调节从集水区输出的碳（C）和氮（N）量方面发挥着重要作用。然而，通过土壤气体途径去除C和N会影响当地的温室气体（GHG）排放预算，并导致气候变化。在一年多的时间里，我们量化了地中海沿岸森林的二氧化碳（CO2）和一氧化二氮（N2 O）的土壤排放，以了解这些生态系统对流域温室气体排放的作用。此外，我们还评估了产生温室气体的主要土壤微生物过程（矿化、硝化和反硝化），以及土壤性质的变化如何随时间和空间的变化而改变温室气体的产生。河岸土壤向大气排放的CO2（1.2-10 g C m−2 d−1）比N2 O（0.001-0.2 mg N m−2 d−1）多，这归因于高呼吸和低反硝化速率。CO2和N2 O的排放量表现出显着的（但拮抗）的空间梯度作为整个河岸带的土壤含水量的变化的结果。深层地下水位燃料大的土壤CO2流出附近的山坡，而N2 O排放量较高，在潮湿的区域相邻的流通道。然而，CO2和N2 O的排放量达到峰值后，春季复湿事件，当土壤含水量，温度和氮的有效性有利于微生物呼吸，硝化和反硝化的最佳条件。总体而言，我们的研究结果突出了水的可利用性对河岸土壤生态地球化学和温室气体排放的作用，并表明气候变化水文制度的改变可以影响微生物过程，产生温室气体以及这些系统的贡献，区域和全球生态地球化学循环。
Abstract. Riparian zones play a fundamental role in regulating the amount of carbon (C) and nitrogen (N) that is exported from catchments. However, C and N removal via soil gaseous pathways can influence local budgets of greenhouse gas (GHG) emissions and contribute to climate change. Over a year, we quantified soil effluxes of carbon dioxide (CO2) and nitrous oxide (N2O) from a Mediterranean riparian forest in order to understand the role of these ecosystems on catchment GHG emissions. In addition, we evaluated the main soil microbial processes that produce GHG (mineralization, nitrification, and denitrification) and how changes in soil properties can modify the GHG production over time and space. Riparian soils emitted larger amounts of CO2 (1.2–10 g C m−2 d−1) than N2O (0.001–0.2 mg N m−2 d−1) to the atmosphere attributed to high respiration and low denitrification rates. Both CO2 and N2O emissions showed a marked (but antagonistic) spatial gradient as a result of variations in soil water content across the riparian zone. Deep groundwater tables fueled large soil CO2 effluxes near the hillslope, while N2O emissions were higher in the wet zones adjacent to the stream channel. However, both CO2 and N2O emissions peaked after spring rewetting events, when optimal conditions of soil water content, temperature, and N availability favor microbial respiration, nitrification, and denitrification. Overall, our results highlight the role of water availability on riparian soil biogeochemistry and GHG emissions and suggest that climate change alterations in hydrologic regimes can affect the microbial processes that produce GHG as well as the contribution of these systems to regional and global biogeochemical cycles.