Elevated temperature and nutrients lead to increased N2O emissions from salt marsh soils from cold and warm climates
Elevated temperature and nutrients lead to increased N2O emissions from salt marsh soils from cold and warm climates
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DOI：
10.1007/s10533-023-01104-0
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发表时间：
2023-12
期刊：
影响因子：
4
通讯作者：
S. Comer-Warner;Sami Ullah;Arunabha Dey;Camille L. Stagg;Tracy Elsey-Quirk;C. Swarzenski;F. Sgouridis;Stefan Krause;Gail L. Chmura
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作者：
S. Comer-Warner;Sami Ullah;Arunabha Dey;Camille L. Stagg;Tracy Elsey-Quirk;C. Swarzenski;F. Sgouridis;Stefan Krause;Gail L. Chmura
盐沼可以减少营养污染，并在土壤中储存大量的“蓝碳”，然而，被封存的碳的价值可能被一氧化二氮(N2O)的排放部分抵消。全球气候和土地利用变化导致温度升高和活性氮(Nr)输入沿海地区。在这里，我们研究了高温(环境 + 5℃)和Nr(双环境浓度)对两个气候地区(加拿大魁北克和美国路易斯安那州)沼泽土壤氮素加工的综合影响。对互花米草(Sporobolus Terniflorus)和短小芽孢子草(Sporobolus Puilus)两种植被类型进行了24小时室内培养实验。在所有四个沼泽地提高处理后，潜在的N2O通量从次要汇到主要来源都有所增加。根据沼泽位置和植被类型的不同，在升高处理下的一天的潜在N2O排放(代表长期的海面变暖或短期的海洋热浪对沿海沼泽土壤温度的影响以及N负载的脉冲)抵消了潜在的年度环境N2O汇的15%-60%。在环境处理下，高纬度沼泽土壤的潜在反硝化速率普遍高于低纬度沼泽土壤，N2O/N2比值较低，表明高纬度沼泽土壤完全反硝化。在高温和氮素处理下，与环境条件相比，高纬度土壤的反硝化潜力较低，而低纬度土壤的反硝化潜力较高，除路易斯安那州外，其余地区都观察到了不完全反硝化作用。小矮人。总体而言，我们的发现表明，在未来全球变化的情景下，气温和Nr的共同上升有可能减少盐沼温室气体(GHG)的汇。
Salt marshes can attenuate nutrient pollution and store large amounts of ‘blue carbon’ in their soils, however, the value of sequestered carbon may be partially offset by nitrous oxide (N2O) emissions. Global climate and land use changes result in higher temperatures and inputs of reactive nitrogen (Nr) into coastal zones. Here, we investigated the combined effects of elevated temperature (ambient + 5℃) and Nr (double ambient concentrations) on nitrogen processing in marsh soils from two climatic regions (Quebec, Canada and Louisiana, U.S.) with two vegetation types,Sporobolus alterniflorus(=Spartina alterniflora) andSporobolus pumilus(=Spartina patens), using 24-h laboratory incubation experiments. Potential N2O fluxes increased from minor sinks to major sources following elevated treatments across all four marsh sites. One day of potential N2O emissions under elevated treatments (representing either long-term sea surface warming or short-term ocean heatwaves effects on coastal marsh soil temperatures alongside pulses of N loading) offset 15–60% of the potential annual ambient N2O sink, depending on marsh site and vegetation type. Rates of potential denitrification were generally higher in high latitude than in low latitude marsh soils under ambient treatments, with low ratios of N2O:N2indicating complete denitrification in high latitude marsh soils. Under elevated temperature and Nr treatments, potential denitrification was lower in high latitude soil but higher in low latitude soil as compared to ambient conditions, with incomplete denitrification observed except in LouisianaS. pumilus. Overall, our findings suggest that a combined increase in temperature and Nr has the potential to reduce salt marsh greenhouse gas (GHG) sinks under future global change scenarios.