九龙江河口湿地4种不同生境土壤微生物代谢限制及碳利用效率  

Soil microbial metabolism limitation and carbon use efficiency in four different wetland habitats of Jiulong River estuary

作　　者：刘娜 杨洋[1] 仝川[1,2] 罗敏[3] 黄佳芳[1,2] LIU Na;YANG Yang;TONG Chuan;LUO Min;HUANG Jiafang(College of Geographical Sciences,Fujian Normal University,Fuzhou 350007;Key Laboratory of Humid Subtropical Eco-geographical Process,Ministry of Education,Fujian Normal University,Fuzhou 350007;College of Environment and Safety Engineering,Fuzhou University,Fuzhou 350116)

机构地区：[1]福建师范大学地理科学学院,福州350007 [2]湿润亚热带生态-地理过程教育部重点实验室,福州350007 [3]福州大学环境与安全工程学院,福州350116

出　　处：《环境科学学报》2023年第6期471-482,共12页Acta Scientiae Circumstantiae

基　　金：国家重点研发计划项目(No.2022YFC3105401);国家自然科学基金项目(No.41801070,42177213);福建省科技厅公益类项目(No.2022R1002007)。

摘　　要：滨海湿地生态系统碳(C)固存效率受到微生物分解者维持养分循环和能量流动相关的代谢能力的影响.为了探究滨海湿地不同植物群落土壤微生物代谢限制状况和碳利用效率(Carbon Use Efficiency,CUE),本研究在九龙江河口湿地中单一红树林群落、单一互花米草群落、红树林与互花米草交错带内以红树林为主的群落和以互花米草为主的群落4个生境采集表层(0~5 cm)和深层(20~40 cm)土壤样品,测定土壤理化指标、土壤微生物生物量的C、氮(N)、磷(P)含量及胞外酶活性,并通过胞外酶活性的C、N、P比例计算矢量长度(VL)和矢量角度(VA)量化微生物的C限制和P限制,通过生物地球化学模型计算微生物CUE.结果表明,4个生境土壤微生物普遍受到C限制和P限制.表层土壤和深层土壤的微生物CUE随生境变化表现出不同的规律,表层土壤微生物CUE随生境显著变化,植被竞争显著降低了微生物CUE,而深层土壤微生物CUE在各个生境保持相对稳定.RDA分析结果发现,不同土层微生物代谢限制与环境因子的相关关系不一致.表层土壤养分与微生物CUE呈正相关关系,与C限制程度呈负相关关系,微生物生物量C、N、P与CUE、P限制程度呈正相关关系,与C限制呈负相关关系,而深层土壤微生物CUE和C限制程度与SOC相关性均较弱,微生物P限制程度与微生物生物量C呈负相关关系.综上所述,我国亚热带河口互花米草入侵红树林湿地后显著影响了湿地表层土壤微生物代谢特征和CUE,混生植物群落内土壤微生物面对更强的C限制,维持更高的胞外酶C∶N、C∶P和更低的CUE,将加剧滨海/河口湿地土壤C库损失.Carbon(C)sequestration of coastal tidal wetland ecosystems is affected by metabolic capacity of microbial decomposers to maintain nutrient cycling and energy flow.To explore the soil microbial metabolic restriction and microbial carbon use efficiency(CUE)of different plant communities in coastal tidal wetlands,we collected the soil samples from the surface(0~5 cm)soil and the deep(20~40 cm)soil in four wetland habitats in the Jiulong River estuary,which are the mangrove community,the Spartina alterniflora community,the community dominated by the mangrove,and the community dominated by the S.alterniflora in the ecotone between the mangrove forest and the S.alterniflora marsh.We measured the soil physicochemical parameters,the contents of soil microbial biomass C,nitrogen(N),phosphorus(P)and the extracellular enzyme activities.The vector length(VL)and the vector Angle(VA)were calculated by the ratio of C,N and P of extracellular enzyme activity,and the microbial CUE was calculated by the biogeochemical model.Soil microorganisms in the four wetland habitats were generally restricted by the contents of C and P.Microbial CUE in the surface and deep soil showed different rules with habitat changes.Microbial CUE in the surface soil significantly changed in the different habitats,vegetation competition significantly reduced the microbial CUE,and microbial CUE in the deep soil relatively remained stable among the four habitats.RDA analysis showed that the correlation between microbial metabolic limitation and environmental factors in the different soil layers was inconsistent.In the surface soil,soil nutrients were positively correlated with microbial CUE,and negatively correlated with C limitation;and the microbial biomass C,N,P was positively correlated with CUE and P limitation,and was negatively correlated with C limitation;while in the deep soil,microbial CUE and C limitation were not strongly correlated with the SOC.The P limitation was negatively correlated with the microbial biomass C.Overall,our findings suggeste

关 键 词：河口湿地 磷限制 碳利用效率 红树林 互花米草沼泽 九龙江 

分 类 号：X171[环境科学与工程—环境科学]