摘要
采集闽江河口淡水芦苇(Phragmites australis)沼泽湿地土壤,添加人造海水稳定3个月后“构造”盐度分别为0‰、2.5‰、11‰和22‰的湿地土壤,以上盐度值分别位于河口区淡水、寡咸水、中咸水和多咸水沼泽湿地的盐度分区范围.室内运用微宇宙(microcosm)厌氧培养实验,并分别添加铵态氮和硝酸盐氮,以期揭示盐度在不同形态氮输入对河口感潮沼泽湿地土壤CH_(4)和CO_(2)产生速率的影响的角色.盐度、施氮形态对河口沼泽湿地土壤BG、CBH、NAG、PHO、PEO和mcrA的活性具有显著的影响,添加铵态氮和硝酸盐氮显著增加沼泽湿地不同盐度土壤的CBH、NAG和mcrA的活性.与对照组相比,添加铵态氮显著增加淡水、寡咸水和中咸水沼泽湿地土壤CH_(4)产生速率,分别增加21.9%、23.6%和40.4%,但对多咸水土壤无显著影响;添加硝酸盐氮后淡水、寡咸水、中咸水土壤CH_(4)产生速率分别降低16.56%、15.56%和19.28%,添加硝酸盐氮显著降低多咸水湿地CH_(4)产生速率19.7%.铵态氮和硝酸盐氮输入显著增加寡咸水和中咸水土壤CO_(2)产生速率,而对淡水和多咸水土壤CO_(2)产生速率无影响.施氮情景下,沼泽土壤CH_(4)和CO_(2)产生速率与pH值、土壤胞外酶活性和mcrA丰度呈显著正相关,与盐度、SOC、Cl^(−)和SO_(4)^(2−)呈显著负相关.随机森林模型结果显示,施氮情景下,盐度、NAG、SO_(4)^(2−)和pH值对CH_(4)和CO_(2)产生速率贡献率最大.研究结果说明:氮负荷增加对于河口区不同盐度沼泽湿地土壤CH_(4)和CO_(2)产生速率的影响不同,今后在制定减缓河口区富营养化对河口沼泽湿地温室气体排放影响的对策和措施时,应考虑到盐度梯度的影响.
In this study,we collected soil samples from the freshwater Phragmites australis marsh at the Minjiang River estuary and constructed wetland soils with different salinities of 0‰,2.5‰,11‰,and 22‰by adding artificial seawater and stabilizing for three months.These salinity values correspond to the ranges of fresh,oligohaline,mesohaline,and polyhaline water zones in estuarine tidal wetlands,respectively.We conducted indoor microcosm anaerobic incubation experiments and meanwhile added ammonium and nitrate to determine role of salinity in the impact of nitrogen additions on CH_(4)and CO_(2)production in estuarine tidal marsh soils.The results showed that the salinity and nitrogen form had significant effects on the activities of BG,CBH,NAG,PHO,PEO,and mcrA,the addition of ammonium and nitrate significantly increased activities of CBH,NAG,and mcrA in the soils with different salinities.Ammonium addition significantly increased CH_(4)production rates in the fresh,oligohaline,and mesohaline water marsh soils by 21.9%,23.6%,and 40.4%,respectively,but had no significant effect on polyhaline soil.Nitrate addition decreased CH_(4)production rates in the fresh,oligohaline,and mesohaline soils by 16.56%、15.56%and 19.28%,respectively,although the drop were not significant(P>0.05),nitrate addition significantly reduced CH_(4)production rates in polyhaline soil by 19.7%.Both ammonium and nitrate addition significantly increased CO_(2)production rates in oligohaline and mesohaline soil,while did not significantly change the CO_(2)production rates in the fresh and polyhaline soil.Under the nitrogen addition,the production rates of CH_(4)and CO_(2)were significantly positively correlated with soil pH,extracellular enzyme activities,and mcrA abundance,and significantly negatively correlated with salinity,SOC,Cl^(-),and SO_(4)^(2−).The results of random forest model prediction showed that under nitrogen addition scenarios,salinity,NAG,SO_(4)^(2−),and pH had the greatest contribution rates to the production rates of CH_(4)and CO_(2).Our results indicate that the impact of nitrogen input on CH_(4)and CO_(2)production rates of estuarine marsh soils varies with salinity.In future,we should consider the influence of salinity gradients when making the strategies and measures to mitigate impact of eutrophication on greenhouse gas emission.
作者
刘思琪
胡芳
展鹏飞
黄佳芳
仝川
LIU Si-qi;HU Fang;ZHAN Peng-fei;HUANG Jia-fang;TONG Chuan(School of Geographical Science,Fujian Normal University,Fuzhou 350117,China;Key Laboratory of Humid Sub-tropical Eco-geographical Process,Ministry of Education,Fujian Normal University,Fuzhou 350117,Chin;Wetland Ecosystem Research Station of Minjiang Estuary,National Forestry and Grassland Administration,Fuzhou 350215,China)
出处
《中国环境科学》
北大核心
2025年第10期5811-5822,共12页
China Environmental Science
基金
国家自然科学基金资助项目(42177213)
国家重点研发计划项目(2022YFC3105401)
中央专项财政支持项目([350182]FJYHZB[GK]2024001)。
