Effects Of Temperature Change On Soil Enzyme Activity And Bacterial Community In Forest-swamp Water Space Sequence

The forest-swamp ecosystem is an important global ecosystem and a transition zone between terrestrial aquatic ecosystems.It has extremely high resource development value and environmental regulation functions and has a lasting positive response to the global climate system.The forest swamp ecosystem responds significantly to changes in water conditions,and changes in climate,soil,vegetation,and other factors affect the hydrological status of the forest swamp ecosystem,thereby affecting various service functions of the forest swamp.As global climate change and human disturbance intensify,the ecological hydrological pattern of the watershed is changed,resulting in changes in soil physical and chemical properties and soil microbial communities in the forest-swamp system,which directly affect the carbon cycle.Whether forest swamps will be converted from carbon sinks to carbon sources has become an important research content.In this paper,the forest-swamp ecological sample zone of typical deciduous broad-leaved forest and coniferous forest in Changbai Mountain was selected,and the research location was determined according to its natural water spatial pattern.Temperature increase test(5-35 ?),which simulates different temperature increase ranges(1 ? / day,2 ? / day,5 ? / day and 10 ? / day),to study the response law of soil enzyme activity and bacterial community to temperature changes,It will help to further explain the changes of soil carbon sink function under positive and negative succession trends of forest and marsh ecosystems,provide scientific support for the correct understanding of the role of temperate forest marshes in the global carbon cycle,and Provide reference and reference for protection,management and restoration.The main conclusions of the study are as follows:(1)Different types of soil enzyme activities have different responses to soil water sequences.The activities of urease and sucrase decrease with the increase of water content.Catalase is different from the two,and the response law to different water content is not obvious;(2)temperature changes have a greater impact on soil enzyme activity.Urease,sucrase,and catalase activities all decreased with increasing temperature;compared with spring,the urease activity of each spot in autumn was significantly decreased,the invertase activity was significantly increased,and there was no significant difference in each spot of catalase.The activity of the three soil enzymes generally showed a law of temperature increase of 10 ? / day> temperature increase of 5 ? / day> temperature increase of 2 ? / day> temperature increase of 1 ? / day;(3)soil bacterial community and soil water content The relevance of the rate varies with different vegetation communities.In the Gushantun broad-leaved forest plot,as the water content increased,the bacterial community changed,the abundance of Proteobacteria increased,and the abundance of Actinobacteria decreased;in the Ha Ni coniferous forest plot In the case,the bacterial community did not change significantly with the water content;(4)The response of soil bacterial community to temperature changes was different.Under natural conditions,the abundance of Acidobacteria in spring is higher than that in autumn,and the abundance of Actinobacteria and Chloroflexi in autumn is significantly higher than that in spring.As the temperature increase slowed down,the abundance of Acidobacteria increased and the abundance of Chloroflexi decreased slightly;(5)Soil enzyme activity was closely related to bacterial communities.Urease activity is extremely significantly positively correlated with Actinobacteria,catalase activity is extremely significantly positively correlated with Proteobacteria and Firmicute,and with other bacterial communities in the soil Negative correlation,and the correlation is not significant.The research results provide scientific support for the correct understanding of the role of temperate forest swamps in the global carbon cycle,provide methods for the study of structural and functional changes in the process of ecosystem succession,and provide references for the protection,management and restoration of forest swamps.