Salinization, inundation and tree mortality interact to affect greenhouse gas emissions from stressed coastal forests
Salinization, inundation and tree mortality interact to affect greenhouse gas emissions from stressed coastal forests
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盐碱化、洪水和树木死亡相互作用，影响受压力的沿海森林的温室气体排放
DOI：
10.1016/j.soilbio.2023.109101
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发表时间：
2023
影响因子：
9.7
通讯作者：
O'Halloran, Thomas L.
中科院分区：
文献类型：
--
作者：
Seyfried, Georgia S.;Chow, Alex T.;O'Halloran, Thomas L.
海平面上升和风暴加剧导致沿海森林土壤盐碱化和淡水淹没，从而导致树木死亡和生态系统碳(C)循环的改变。然而，目前尚不清楚盐度和淹没的增加是否会影响温室气体（GHG）的排放以反馈气候变化。为了评估情景盐度和脉冲盐度对沿海森林温室气体通量的影响，我们对收集的完整土壤岩心的二氧化碳和甲烷通量进行了连续测量：1)以火炬松（Pinus taeda）为主的高地森林和以baldcypress （Taxodium distichum）为主的淡水沼泽；2)在经历高与低盐碱化和相关树木死亡率的森林类型中的邻近森林；3)飓风相关风暴潮的脉冲盐度前后。在实验室中，所有土壤芯暴露于三种不同水平的雨水添加中，以评估盐碱化和淹没之间潜在的相互作用。我们发现慢性盐碱化和相关的树木死亡降低了小叶林内的土壤co2通量，但在湿地淹没模式下，秃柏林内的土壤co2通量没有降低，这可能是驱动立地效应的原因。此外，在高地火炬林中，风暴潮的脉冲盐度显示出增加ch4通量的潜力。最后，雨水淹没对ch4通量的影响在低盐度林分大于高盐度林分，表明盐渍化可能抑制了雨水淹没对ch4通量的影响。总体而言，我们表明，在受胁迫的沿海森林中，生物和非生物条件之间的复杂相互作用可以改变温室气体排放，这突出了未来研究的需要，重点是了解在不断变化的环境条件下沿海森林驱动温室气体通量的机制。
Sea level rise and intensifying storms cause salinization and freshwater inundation of coastal forest soils which can result in tree mortality and altered ecosystem carbon (C) cycling. However, it is not yet clear if increased salinity and inundation will affect greenhouse gas (GHG) emissions to feed back with climate change. To assess the impacts ofin situchronic and pulsed salinity on GHG fluxes from coastal forests, we made continuous measurements of carbon dioxide and methane fluxes from intact soil cores collected in 1) an upland forest dominated by loblolly pine (Pinus taeda) and a freshwater swamp dominated by baldcypress (Taxodium distichum) 2) adjacent forest stands within forest types experiencing high versus low salinization and associated tree mortality and 3) before and after pulsed salinity from a hurricane related storm surge. In lab mesocosms, all soil cores were exposed to three levels of rainwater addition to assess potential interactive effects between salinization and inundation. We found that chronic salinization and associated tree mortality decreased soil CO2fluxes in loblolly, but not baldcypress forest within situsoil inundation patterns potentially driving the site effect. Additionally, in an upland loblolly forest, pulsed salinity from a storm surge exhibited the potential to increase CH4fluxes. Finally, the effect of rainwater inundation on CH4fluxes was greater in low compared to high salinity stands suggesting that salinization may have suppressed the effects of rainwater inundation on CH4fluxes. Overall, we show that complex interactions between biotic and abiotic conditions in stressed coastal forests can alter GHG emissions, highlighting a need for future research focused on understanding the mechanisms driving GHG fluxes from coastal forests under changing environmental conditions.