Experimentally simulated sea level rise destabilizes carbon-mineral associations in temperate tidal marsh soil
Experimentally simulated sea level rise destabilizes carbon-mineral associations in temperate tidal marsh soil
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DOI：
10.1007/s10533-023-01024-z
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发表时间：
2023-02
期刊：
影响因子：
4
通讯作者：
Sean Fettrow;R. Vargas;A. Seyfferth
中科院分区：
文献类型：
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作者：
Sean Fettrow;R. Vargas;A. Seyfferth
海平面上升（SLR）如何改变潮汐盐沼土壤中的碳（C）动态尚未解决。水动力学的变化会影响有机无机物的组合，从而影响溶解有机碳（DOC）通量。由于SLR增加了淹没的持续时间，我们假设，横向DOC出口将增加，由于还原溶解的含碳铁（Fe）氧化物，不稳定的土壤碳储量和影响温室气体排放。为了测试这一点，土芯（0-8厘米深），从高沼泽的温带盐沼，目前经历的水位变化和土壤氧化还原振荡，由于春潮小潮。实验模拟SLR的中生态系统不断淹没高沼泽土壤，并与控制条件下，水位振荡的小潮周期中生态系统进行了比较。SLR处理的孔隙水DOC、侧向DOC和孔隙水还原态Fe（Fe 2+）浓度显著高于对照（分别为1.7 ± 0.5 mM、0.63 ± 0.14 mM和0.15 ± 0.11 mM）（1.2 ± 0.35 mM、0.56 ± 0.15 mM和0.08 ± 0.15 mM，分别用Fe扩展X射线吸收精细结构光谱进行的固相分析进一步揭示，SLR导致Fe氧化物减少> 3倍。此外，由于抑制了CO2排放，SLR下的总体全球变暖潜势（GWP）降低。我们的数据表明，SLR可能会增加目前的C股票的横向C出口溶解含C的铁氧化物，但减少土壤痕量气体排放的整体GWP。这些研究结果对理解未来SLR情景下SOC动态的命运具有重要意义。
How sea level rise (SLR) alters carbon (C) dynamics in tidal salt marsh soils is unresolved. Changes in hydrodynamics could influence organo-mineral associations, influencing dissolved organic carbon (DOC) fluxes. As SLR increases the duration of inundation, we hypothesize that lateral DOC export will increase due to reductive dissolution of C-bearing iron (Fe) oxides, destabilizing soil C stocks and influencing greenhouse gas emissions. To test this, soil cores (0–8 cm depth) were collected from the high marsh of a temperate salt marsh that currently experiences changes in water level and soil redox oscillation due to spring-neap tides. Mesocosms experimentally simulated SLR by continuously inundating high marsh soils and were compared to mesocosms with Control conditions, where the water level oscillated on a spring-neap cycle. Porewater DOC, lateral DOC, and porewater reduced Fe (Fe2+) concentrations were significantly higher in SLR treatments (1.7 ± 0.5 mM, 0.63 ± 0.14 mM, and 0.15 ± 0.11 mM, respectively) than Control treatments (1.2 ± 0.35 mM, 0.56 ± 0.15 mM, and 0.08 ± 01 mM, respectively Solid phase analysis with Fe extended X-ray absorption fine-structure spectroscopy further revealed that SLR led to > 3 times less Fe oxide-C coprecipitates than Control conditions In addition, the overall global warming potential (GWP) decreased under SLR due to suppressed CO2emissions. Our data suggest that SLR may increase lateral C export of current C stocks by dissolving C-bearing Fe oxides but decrease the overall GWP from emissions of soil trace gases. These findings have implications for understanding the fate of SOC dynamics under future SLR scenarios.