Effect of Drought-Induced Salinization on Wetland Methane Emissions, Gross Ecosystem Productivity, and Their Interactions
Effect of Drought-Induced Salinization on Wetland Methane Emissions, Gross Ecosystem Productivity, and Their Interactions
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DOI：
10.1007/s10021-019-00430-5
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发表时间：
2020-04-01
期刊：
影响因子：
3.7
通讯作者：
Baldocchi, Dennis D.
中科院分区：
文献类型：
--
作者：
Chamberlain, Samuel D.;Hemes, Kyle S.;Baldocchi, Dennis D.
河口盐度梯度影响湿地碳储量、甲烷（CH 4）地球化学和植物生产力。河口淡水湿地在干旱期间可能会经历盐度的增加，然而，盐渍化对温室气体（GHG）排放的影响是不确定的。我们测量了2011-2017年加州干旱期间经历盐碱化的湿地的生态系统规模温室气体排放，并使用信息理论分析来量化CH 4通量与两个主要环境驱动因素之间的耦合和因果相互作用;总生态系统光合作用和温度。然后，机器学习模型被用来估计盐碱化引起的CH 4通量和植物生产力的变化。我们观察到动态的CH 4通量驱动器的关系在整个盐碱化干扰事件，温度连接加强，生产力连接在盐碱化过程中抑制。年总生态系统生产力减少了64%，在盐碱化高峰期，而每年的CH 4排放量只减少了10%，这表明其他CH 4基质源补偿减少在最近的光合作用。我们的研究结果表明，应用信息理论和机器学习方法的生态分析的价值，并建议干旱引起的盐碱化可能会增加温室气体排放的河口淡水湿地。
Salinity gradients across estuaries influence wetland carbon storage, methane (CH4) biogeochemistry, and plant productivity. Estuarine freshwater wetlands may experience increases in salinity during drought; however, the impact of salinization on greenhouse gas (GHG) emissions is uncertain. We measured ecosystem-scale GHG emissions from a wetland experiencing salinization during the 2011-2017 California drought and used information theory analyses to quantify couplings and causal interactions between CH4 fluxes and two dominant environmental drivers; gross ecosystem photosynthesis and temperature. Machine learning models were then used to estimate salinization-induced changes in CH4 fluxes and plant productivity. We observed dynamic CH4 flux-driver relationships across the salinization disturbance event, where temperature connections strengthened, and productivity connections dampened during salinization. Annual gross ecosystem productivity reduced by 64% during peak salinization, whereas annual CH4 emissions only reduced by 10%, suggesting that other CH4 substrate sources compensated for reductions in recent photosynthate. Our results demonstrate the value of applying information theory and machine learning approaches to ecological analyses and suggest that drought-induced salinization may increase GHG emissions from estuarine freshwater wetlands.