Microplastics(MPs)in river ecosystems significantly affect sediment microbial communities and biogeochemical cycling.However,the specific microbial responses to distinct MPs and their subsequent effects on greenhouse ...Microplastics(MPs)in river ecosystems significantly affect sediment microbial communities and biogeochemical cycling.However,the specific microbial responses to distinct MPs and their subsequent effects on greenhouse gas(GHG)emissions remain poorly understood.In this study,the effects of conventional polyvinyl chloride(PVC)and biodegradable polylactic acid(PLA)on sediment microbial communities and GHG emissions were compared.Both PVC and PLA increased sediment total organic carbon(STOC)by 31.3%and 36.7%,respectively,leading to an increase in sediment bacterial abundance.Notably,compared with PLA,PVC reduced bacterial richness more significantly.Community composition and FAPROTAX function prediction analysis revealed that PVC-enriched taxa involved in nitrate reduction(e.g.,Desulfuromonas,Hydrogenophage,Azospira)resulted in a significant decrease in NO3−contents.In contrast,PLA increased the abundance of microorganisms associated with organic matter degradation(Chitinophagaceae,Comamonadaceae,and Caulobacteraceae).Both PVC and PLA significantly reduced the relative abundance of the mcrA gene,leading to decreased CH4 fluxes,likely due to competition from enriched acetate-utilizing bacteria(Desulfuromonas,Pseudomonas,and Azospira).Additionally,PLA significantly reduced the abundance of the nirK gene.This study systematically elucidates the differential effects of PVC and PLA on microbial community structure and GHG emissions,providing new insights into the ecological impacts of MPs.展开更多
Background Biochar is widely recognized for its capacity to capture and store carbon in soil attributed to its stable structure. However, in most field studies examining the effects of biochar application on soil resp...Background Biochar is widely recognized for its capacity to capture and store carbon in soil attributed to its stable structure. However, in most field studies examining the effects of biochar application on soil respiration, the impact of rainfall events on the experimental outcomes has not been taken into account. To address the existing gap in this research field, we conducted a one-year study on soil respiration in an urban camphor forest and collected the data of soil respiration, soil temperature, soil moisture, and the rainfall events closest to the soil respiration monitoring time. We specifically examined how different stages of rainfall events influenced soil respiration in relation to biochar application.Results This study found that the annual average soil respiration rate increased with the doses of biochar application, and the soil respiration rate under the biochar application at the dose of 45 t/ha showed a significant rise. The stages of rainfall events, rainfall amount, and the interaction effect of the two, and biochar doses significantly affected soil respiration. The parameters in the regression model for soil respiration, soil temperature and moisture varied with the different stages of rainfall events and the doses of biochar application. The biochar application eliminated the significant effect of soil moisture on soil respiration during one day after rainfall events. The significant correlation between soil moisture and the temperature sensitivity of soil respiration(Q10) was eliminated by biochar application, both during one day after rainfall events and more than eight days after rainfall events.Conclusions Our findings indicated that the rice straw biochar application has a short-term positive effect on soil respiration in urban camphor forests. The rainfall events affect the field soil respiration monitored in the biochar applications, possibly by affecting the soil respiration response to soil temperature and moisture under different doses of biochar application. The impact of rainfall events on soil respiration in biochar application experiments should be considered in future forest monitoring management and practice.展开更多
基金supported by the Fund for National Key R&D Program of China(2021YFC3200401)the National Natural Science Foundation of China(Grant Nos.52170024 and 52039001).
文摘Microplastics(MPs)in river ecosystems significantly affect sediment microbial communities and biogeochemical cycling.However,the specific microbial responses to distinct MPs and their subsequent effects on greenhouse gas(GHG)emissions remain poorly understood.In this study,the effects of conventional polyvinyl chloride(PVC)and biodegradable polylactic acid(PLA)on sediment microbial communities and GHG emissions were compared.Both PVC and PLA increased sediment total organic carbon(STOC)by 31.3%and 36.7%,respectively,leading to an increase in sediment bacterial abundance.Notably,compared with PLA,PVC reduced bacterial richness more significantly.Community composition and FAPROTAX function prediction analysis revealed that PVC-enriched taxa involved in nitrate reduction(e.g.,Desulfuromonas,Hydrogenophage,Azospira)resulted in a significant decrease in NO3−contents.In contrast,PLA increased the abundance of microorganisms associated with organic matter degradation(Chitinophagaceae,Comamonadaceae,and Caulobacteraceae).Both PVC and PLA significantly reduced the relative abundance of the mcrA gene,leading to decreased CH4 fluxes,likely due to competition from enriched acetate-utilizing bacteria(Desulfuromonas,Pseudomonas,and Azospira).Additionally,PLA significantly reduced the abundance of the nirK gene.This study systematically elucidates the differential effects of PVC and PLA on microbial community structure and GHG emissions,providing new insights into the ecological impacts of MPs.
基金funded by the Forestry Science and Technology Research and Innovation Project of China(grant no.XLKY202322)Joint Funds of National Natural Science Foundation of China(grant no.U21A20187)+6 种基金Key Research and Development Program of Hunan province(grant no.2023SK2055)National Key R&D Program of China(grant no.2020YFA0608100)Creative Research Groups of Provincial Natural Science Foundation of Hunan(grant no.2024JJ1016)Water Science and Technology Project of Hunan province(grant no.XSKJ2022068-35)Hunan Provincial Natural Science Foundation of China(grant no.2024JJ5639)Changsha Municipal Natural Science Foundation(grant no.kq2402249)Three Gorges follow-up project of the Ministry of Water Resources(grant no.HY110161A0012022)
文摘Background Biochar is widely recognized for its capacity to capture and store carbon in soil attributed to its stable structure. However, in most field studies examining the effects of biochar application on soil respiration, the impact of rainfall events on the experimental outcomes has not been taken into account. To address the existing gap in this research field, we conducted a one-year study on soil respiration in an urban camphor forest and collected the data of soil respiration, soil temperature, soil moisture, and the rainfall events closest to the soil respiration monitoring time. We specifically examined how different stages of rainfall events influenced soil respiration in relation to biochar application.Results This study found that the annual average soil respiration rate increased with the doses of biochar application, and the soil respiration rate under the biochar application at the dose of 45 t/ha showed a significant rise. The stages of rainfall events, rainfall amount, and the interaction effect of the two, and biochar doses significantly affected soil respiration. The parameters in the regression model for soil respiration, soil temperature and moisture varied with the different stages of rainfall events and the doses of biochar application. The biochar application eliminated the significant effect of soil moisture on soil respiration during one day after rainfall events. The significant correlation between soil moisture and the temperature sensitivity of soil respiration(Q10) was eliminated by biochar application, both during one day after rainfall events and more than eight days after rainfall events.Conclusions Our findings indicated that the rice straw biochar application has a short-term positive effect on soil respiration in urban camphor forests. The rainfall events affect the field soil respiration monitored in the biochar applications, possibly by affecting the soil respiration response to soil temperature and moisture under different doses of biochar application. The impact of rainfall events on soil respiration in biochar application experiments should be considered in future forest monitoring management and practice.
