During a study of fungal diversity in the Puruogangri Glacier ecosystem on the Qinghai-Xizang Plateau,a strain was isolated from soil samples at the glacier forefields using the dilution plate method,and identified as...During a study of fungal diversity in the Puruogangri Glacier ecosystem on the Qinghai-Xizang Plateau,a strain was isolated from soil samples at the glacier forefields using the dilution plate method,and identified as Sinophaeosphaeria xizangensis gen.et sp.nov.Morphological analysis revealed that the fungus produced olive to olive-brown conidia on PDA medium.The conidia consist of two or more cells,arranged in curved or irregular chains.Some cells slightly swollen,forming distinctly prominent bulging regions or aggregating into dense,hammer-shaped structures.Phylogenetic analyses based on five genetic loci,including internal transcribed spacer(ITS),large subunit ribosomal DNA(LSU),small subunit ribosomal DNA(SSU),RNA polymeraseⅡsecond largest subunit(rpb2),and translation elongation factor 1-α(tef1-α),indicate that this fungus represents a previously undescribed lineage within the family Phaeosphaeriaceae.This genus is located at the base of a branch that includes Paraloratospora,Loratospora,Wingfieldomyces and Sulcispora,revealing its unique evolutionary position.展开更多
Antibiotic resistance genes(ARGs)are increasingly recognized as a global public health threat,with glaciers acting as reservoirs for ARGs transported via atmospheric pathways.Warming climate accelerates glacier meltin...Antibiotic resistance genes(ARGs)are increasingly recognized as a global public health threat,with glaciers acting as reservoirs for ARGs transported via atmospheric pathways.Warming climate accelerates glacier melting,releasing ARGs into downstream environments,posing ecological health and sustainable aquatic ecosystem development challenges.However,the distribution profiles of ARGs and their risks in glaciers from the polar region remain unclear.This study used 294 metagenomic sequences to investigate the distribution and risks of ARGs in glaciers across the Qinghai-Xizang Plateau,Antarctica,and the Arctic regions and compared them with adjacent and anthropogenically impacted environments.Among the three glacier regions studied,the Qinghai-Xizang Plateau exhibited the highest abundance of ARGs,whereas Antarctica displayed the lowest.ARG abundance in adjacent environments was comparable to that in the glaciers of the Qinghai-Xizang Plateau,but in the anthropogenically impacted environment,it was significantly higher than in glaciers.A shared resistome was identified in glaciers,dominated by bacitracin,multidrug,and macrolide-lincosamide-streptogramin(MLS)resistance genes.The bacA gene,which is related to bacitracin resistance,was the most common subtype,indicating that it is naturally present in microbial communities of glaciers.Risk assessments showed that 74.1%–78.9%of ARGs were low-risk in the Qinghai-Xizang Plateau and polar glaciers,indicating minimal human influence.However,7.3%–8.0%were classified as high-risk,posing potential threats through horizontal gene transfer(HGT)and the spread of multidrug-resistant pathogens.These findings highlight the need to monitor ARGs in glacier environments,as climate change accelerates glacier melting and subsequent release of ARGs into downstream ecosystems.展开更多
Ice cores play an important role in the reconstruction of historical atmospheric information.The glacier of the Tibetan Plateau is influenced by the Indian monsoon and westerly winds,which divide the Tibetan Plateau i...Ice cores play an important role in the reconstruction of historical atmospheric information.The glacier of the Tibetan Plateau is influenced by the Indian monsoon and westerly winds,which divide the Tibetan Plateau into monsoon-and westly influenced regions.These atmospheric circulations bring distinct microbial communities to glaciers,with the microbial dispersal process being also influenced by atmospheric factors.However,the potential influence of between bacterial abundance and atmospheric factors is not well known.To reveal potential mechanisms controlling bacterial abundance between two regions,we obtained bacterial abundance and atmospheric records for the past 46 years from two ice cores located within these regions.Statistical regression models were constructed to fit the relationship between bacterial abundance and atmospheric factors.Generalized additive model(GAM)was superior in modeling bacterial abundance compared with linear models and showed that the key factors affecting bacterial abundance were different in the monsoon-and westerly-dominated regions.Specifically,atmospheric dust and black carbon were the key factors for the monsoon-dominated region,and westerly index was the key factor for the westerly-dominated region.The model outputs confirm that atmospheric black carbon plays an important role in affecting bacterial abundance for the glacier located within the monsoon-dominated region,particularly in recent decades.The model also predicted that bacterial abundance will increase by 27%with a doubled black carbon deposition.We quantify and model for the first time that relationship between bacterial abundance and atmospheric black carbon in Tibetan glaciers change over time based on GAM models.展开更多
Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how woul...Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau(QTP)remains largely unknown.Here we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River(TTH)and May 2022 for Aerjin(ARJ),and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA gene.Our study revealed distinct bacterial communities,with significant differences in the relative abundances of Proteobacteria(P<0.05),Acidobacteriota(P<0.001),Bacteroidota(P<0.05),and Planctomycetota(P<0.001)between the active layer and the permafrost layer.More importantly,we found that interspecies interactions,including both positive and negative associations,were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly process.Our findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes,with interspecies interactions accounting for more than 58%and 63%of all assembly mechanisms,respectively.This is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP,highlighting the importance of considering interspecies interactions in future modeling efforts.Our work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.展开更多
The Yellow River(YR),China’s second-longest river,remains understudied regarding its greenhouse gases(GHGs)emissions,particularly the impacts of urban drainage ditches and wastewater treatment facilities on regional ...The Yellow River(YR),China’s second-longest river,remains understudied regarding its greenhouse gases(GHGs)emissions,particularly the impacts of urban drainage ditches and wastewater treatment facilities on regional GHGs dynamics.This study investigated methane(CH_(4))and carbon dioxide(CO_(2))concentrations,fluxes and stable carbon isotopes(δ^(13)C-CH_(4)and δ^(13)C-CO_(2))across six main stream,three ditches,and one wastewater treatment site along the upper Lanzhou section of the YR,spanning from the urban entrance(36.176°N,103.449°E)to the exit of Lanzhou city(36.056°N,104.020°E).Measured CH_(4)diffusion fluxes in mainstem sites ranged from 0.01 to 2.58 mmol·m^(−2)·d^(−1)(mean:0.36 mmol·m^(−2)·d^(−1)),while ebullitive fluxes(gas bubbles)ranged from 0.01 to 18.89 mmol·m^(−2)·d^(−1)(mean:0.90 mmol·m^(−2)·d^(−1)).CO_(2)diffusion fluxes varied between 9.16–92.80 mmol·m^(−2)·d^(−1)(averaged:39.11 mmol·m^(−2)·d^(−1))at these locations.Ebullition(bubble)fluxes accounted for 53.1%±22.4%(range:9.0%to 98.4%)to total CH_(4)emissions(diffusion plus ebullition),with peak fluxes occurring during summer,indicating its significance as a CH_(4)transport mechanism.Notably,both diffusion CH_(4)and CO_(2)fluxes and ebullitive CH_(4)rates at ditch sites substantially exceeded those in mainstream reaches.The lowest CH_(4)and highest CO_(2)concentrations were observed at a wastewater treatment site,likely resulting from the removal of high organic loads.Acetoclastic methanogenesis—the process converting acetate-derived methyl groups to CH_(4)—was identified as the dominant production pathway in both mainstream and ditch environments.CH_(4)and CO_(2)flux magnitudes in the upper YR(Lanzhou section)were comparable to those observed in subtropical Yangtze River tributaries.These results demonstrate that anthropogenic influences significantly enhance CO_(2)/CH_(4)emissions,and the lateral exports of dissolved carbon(DIC and DOC)in the main stream site was quantified.,which cannot be overlooked.The findings emphasize the critical need to account for pronounced spatiotemporal variations in arid-region GHG fluxes to improve basin-scale estimates for the YR.展开更多
Glaciers are considered to be‘climate-sensitive indicators'and‘solid reservoirs',and their changes significantly impact regional water security.The mass balance(MB)from 2011 to 2020 of the Qiyi Glacier in th...Glaciers are considered to be‘climate-sensitive indicators'and‘solid reservoirs',and their changes significantly impact regional water security.The mass balance(MB)from 2011 to 2020 of the Qiyi Glacier in the northeast Tibetan Plateau is presented based on field observations.The glacier showed a persistent negative balance over 9 years of in-situ observations,with a mean MB of-0.51 m w.e.yr^(-1).The distributed energy-mass balance model was used for glacier MB reconstruction from 1980 to 2020.The daily meteorological data used in the model were from HAR v2 reanalysis data,with automatic weather stations located in the middle and upper parts of the glacier used for deviation correction.The average MB over the past 40 years of the Qiyi Glacier was-0.36 m w.e.yr^(-1)with the mass losses since the beginning of the 21st century,being greater than those in the past.The glacier runoff shows a significant increasing trend,contributing~81%of the downstream river runoff.The albedo disparity indicates that the net shortwave radiation is much higher in the ablation zone than in the accumulation zone,accelerating ablation-area expansion and glacier mass depletion.The MB of the Qiyi Glacier is more sensitive to temperature and incoming shortwave radiation variation than precipitation.The MB presented a non-linear reaction to the temperature and incoming shortwave radiation.Under future climate warming,the Qiyi Glacier will be increasingly likely to deviate from the equilibrium state,thereby exacerbating regional water balance risks.It is found that the mass losses of eastern glaciers are higher than those of western glaciers,indicating significant spatial heterogeneity that may be attributable to the lower altitude and smaller area distribution of the eastern glaciers.展开更多
Glacial lakes,intimately linked to glacier termini,are crucial landscape features of the Qinghai-Xizang Plateau(QXP,Qinghai-Tibet Plateau)and the Arctic.Climate warming has accelerated glacier retreat and the rapid ex...Glacial lakes,intimately linked to glacier termini,are crucial landscape features of the Qinghai-Xizang Plateau(QXP,Qinghai-Tibet Plateau)and the Arctic.Climate warming has accelerated glacier retreat and the rapid expansion of glacial lakes in both regions.Despite being typically considered harsh environments,these lakes serve as vital reservoirs for microbial biodiversity and carbon metabolism.In the face of climate change,glacial lake ecosystems over the QXP and the Arctic are undergoing unprecedentedtransformations.Thisopinioneditorial highlights the significance of conducting research and establishing long-term monitoring programs focused on microbial carbon metabolism in these glacial lakes.展开更多
Accelerated glacier melt driven by global warming is increasing nitrate(NO_(3)^(-)) fluxes to downstream ecosystems,thereby attracting wide attention to nitrogen cycling in glacial-fed regions.Proglacial lakes are clo...Accelerated glacier melt driven by global warming is increasing nitrate(NO_(3)^(-)) fluxes to downstream ecosystems,thereby attracting wide attention to nitrogen cycling in glacial-fed regions.Proglacial lakes are closely connected to glaciers,and glacier-derived NO_(3)^(-)plays a critical role in regulating lake water NO_(3)^(-)concentrations.However,the relative contributions of glacier runoff(GR) versus in-lake biogeochemical processes to lake water NO_(3)^(-)remain poorly understood.This study uses measurements of NO_(3)^(-)concentrations and isotopic compositions(δ^(15)O-NO_(3)^(-),δ^(18)O-NO_(3)^(-),and Δ^(17)O-NO_(3)^(-))from the Qiangyong Glacier watershed on the Tibetan Plateau,combined with the MixSIAR model,to quantify the relative contributions of different NO_(3)^(-)sources.The results showed that GR was the dominant source to lake water NO_(3)^(-)during the melting season,accounting for 83%±5%,followed by in-lake microbial nitrification(MN) contributing 15%±4% and direct atmospheric deposition contributing 2%±2%.Further analysis reve aled that both GR input and internal lake processes controlled the seasonal variations of NO_(3)^(-)concentrations.During the early melt season,GR and enhanced in-lake nitrification increase NO_(3)^(-)concentrations,while sediment-mediated physical adsorption may contribute to their subsequent decrease.In contrast,during the non-melt season,NO_(3)^(-)concentrations gradually declined through microbial removal processes,such as denitrification and assimilation.This study quantified the relative contributions of GR and in-lake MN to lake NO_(3)^(-),highlighting that proglacial lakes are hotspots for nitrogen transformation.展开更多
Glacier-related slope failures,including ice avalanches,ice-rock avalanches,glacier collapses,and rock avalanches on glaciers,are generally characterized by large collapse volumes,solid-liquid phase transition,and hig...Glacier-related slope failures,including ice avalanches,ice-rock avalanches,glacier collapses,and rock avalanches on glaciers,are generally characterized by large collapse volumes,solid-liquid phase transition,and high mobility[1].They are one of the major types of geo-hazards in high mountain areas.Glacier-related slope failures have cascading effects since they often evolve into glacial lake outburst floods(GLOFs),debris flows,and dammed lakes,which significantly prolong and amplify the impacts of the hazard.Tragic slope failures have cumulatively claimed more than tens of thousands of lives.For example,the 1962 and 1970 Huascaran events in the Peruvian Andes caused approximately 20,000 deaths[2],and the 2021 Chamoli ice-rock avalanche in the Indian Himalayas left more than 200 people dead or missing[3].展开更多
Background Microbial communities in different plant compartments are relatively independent entities.However,the influence of environmental factors on the microbial community in different compartments of periglacial p...Background Microbial communities in different plant compartments are relatively independent entities.However,the influence of environmental factors on the microbial community in different compartments of periglacial plants remains unclear.In this study,we quantified the bacterial communities in the rhizosphere soil,as well as root and leaf endosphere compartments of a periglacial plant,Potentilla fruticosa var.albicans,using high-throughput DNA sequencing.Moreover,we evaluated the impacts of habitat types(glacier terminus zone,moraine ridge,and alpine meadow)on the bacterial community in different plant compartments of Potentilla fruticosa var.albicans.Results Our results showed that habitat type had a significant effect on the alpha diversity(Chao1 richness)of endophytic bacteria,but not on the rhizospheric bacteria.The community composition of rhizospheric and endophytic bacteria was significantly different across the three habitats,and habitat type had a greater effect on the endophytic bacteria than on rhizospheric bacteria.The contribution of rhizosphere soil to the root and leaf endophytes decreased with the transformation of habitats from glacier terminus zone to alpine meadow.In contrast,host selection pressure sequentially increased from the glacier terminus zone to the moraine ridge to the alpine meadow.Furthermore,we found that the bacterial co-occurrence network in the alpine meadow was more modular but had lower complexity and connectedness than that in the glacier terminus zone.The bacterial community was governed primarily by stochastic processes regardless of habitat type.Conclusion This study reveals that the diversity and composition of endophytic bacteria associated with Potentilla fruticosa var.albicans are more affected by habitat types than that of rhizospheric bacteria.Our study also demonstrates that the assembly patterns and co-occurrence patterns of bacterial communities associated with Potentilla fruticosa var.albicans vary by habitat type.These results advance the current understanding of community assembly and ecological interactions of microbial communities associated with periglacial plants.展开更多
Microorganisms play an essential role in the glacier carbon cycle;how they transform organic matter in mountain glacial cryoconite remains to be studied.Here,we applied ultra-high resolution Fourier transform ion cycl...Microorganisms play an essential role in the glacier carbon cycle;how they transform organic matter in mountain glacial cryoconite remains to be studied.Here,we applied ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)and deep sequencing of 16S rRNA gene,to investigate the temporal microbial transformation of dissolved organic matter(DOM)of the Tibetan Plateau cryoconite.During the 60-day incubation,we found that DOM in cryoconite underwent a three-stage transformation,with decreasing bioavailability over time.The microbial community did not change much in the first week while degrading DOM molecules that were associated with higher H/C_(wa)and lower O/C_(wa).During days 15-30,DOM composition remained stable while microbial diversity increased.By day 60,the DOM was microbially converted into a higher state of recalcitrance,with higher values of aromatic index,O/C_(wa),and lower H/C_(wa),which contained molecules containing more heteroatoms.Cooperation among various microbial taxa,like Cyanobacteria,Bacteroidota,Gammaproteobacteria,Firmicutes,and Actinobacteriota,drove the DOM transformation in cryoconite.This study sheds light on the in-situ transformation of DOM composition meditated by microbial populations in cryoconite at a temporal scale,providing new insights into understanding the microbial roles in the glacier organic carbon transformation.展开更多
基金supported by the Second Xizang Plateau Scientific Expedition and Research Program(2024QZKK02010303)the Second Qinghai-Xizang Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0503).
文摘During a study of fungal diversity in the Puruogangri Glacier ecosystem on the Qinghai-Xizang Plateau,a strain was isolated from soil samples at the glacier forefields using the dilution plate method,and identified as Sinophaeosphaeria xizangensis gen.et sp.nov.Morphological analysis revealed that the fungus produced olive to olive-brown conidia on PDA medium.The conidia consist of two or more cells,arranged in curved or irregular chains.Some cells slightly swollen,forming distinctly prominent bulging regions or aggregating into dense,hammer-shaped structures.Phylogenetic analyses based on five genetic loci,including internal transcribed spacer(ITS),large subunit ribosomal DNA(LSU),small subunit ribosomal DNA(SSU),RNA polymeraseⅡsecond largest subunit(rpb2),and translation elongation factor 1-α(tef1-α),indicate that this fungus represents a previously undescribed lineage within the family Phaeosphaeriaceae.This genus is located at the base of a branch that includes Paraloratospora,Loratospora,Wingfieldomyces and Sulcispora,revealing its unique evolutionary position.
基金supported by the State Key Program of National Natural Science of China(Grant No.42330410)National Natural Science Foundation of China(Grant No.42101128)。
文摘Antibiotic resistance genes(ARGs)are increasingly recognized as a global public health threat,with glaciers acting as reservoirs for ARGs transported via atmospheric pathways.Warming climate accelerates glacier melting,releasing ARGs into downstream environments,posing ecological health and sustainable aquatic ecosystem development challenges.However,the distribution profiles of ARGs and their risks in glaciers from the polar region remain unclear.This study used 294 metagenomic sequences to investigate the distribution and risks of ARGs in glaciers across the Qinghai-Xizang Plateau,Antarctica,and the Arctic regions and compared them with adjacent and anthropogenically impacted environments.Among the three glacier regions studied,the Qinghai-Xizang Plateau exhibited the highest abundance of ARGs,whereas Antarctica displayed the lowest.ARG abundance in adjacent environments was comparable to that in the glaciers of the Qinghai-Xizang Plateau,but in the anthropogenically impacted environment,it was significantly higher than in glaciers.A shared resistome was identified in glaciers,dominated by bacitracin,multidrug,and macrolide-lincosamide-streptogramin(MLS)resistance genes.The bacA gene,which is related to bacitracin resistance,was the most common subtype,indicating that it is naturally present in microbial communities of glaciers.Risk assessments showed that 74.1%–78.9%of ARGs were low-risk in the Qinghai-Xizang Plateau and polar glaciers,indicating minimal human influence.However,7.3%–8.0%were classified as high-risk,posing potential threats through horizontal gene transfer(HGT)and the spread of multidrug-resistant pathogens.These findings highlight the need to monitor ARGs in glacier environments,as climate change accelerates glacier melting and subsequent release of ARGs into downstream ecosystems.
基金supported by the National Key Research and Development Program of China(No.2021YFC2300904)the National Natural Science Foundation of China(No.42101128).
文摘Ice cores play an important role in the reconstruction of historical atmospheric information.The glacier of the Tibetan Plateau is influenced by the Indian monsoon and westerly winds,which divide the Tibetan Plateau into monsoon-and westly influenced regions.These atmospheric circulations bring distinct microbial communities to glaciers,with the microbial dispersal process being also influenced by atmospheric factors.However,the potential influence of between bacterial abundance and atmospheric factors is not well known.To reveal potential mechanisms controlling bacterial abundance between two regions,we obtained bacterial abundance and atmospheric records for the past 46 years from two ice cores located within these regions.Statistical regression models were constructed to fit the relationship between bacterial abundance and atmospheric factors.Generalized additive model(GAM)was superior in modeling bacterial abundance compared with linear models and showed that the key factors affecting bacterial abundance were different in the monsoon-and westerly-dominated regions.Specifically,atmospheric dust and black carbon were the key factors for the monsoon-dominated region,and westerly index was the key factor for the westerly-dominated region.The model outputs confirm that atmospheric black carbon plays an important role in affecting bacterial abundance for the glacier located within the monsoon-dominated region,particularly in recent decades.The model also predicted that bacterial abundance will increase by 27%with a doubled black carbon deposition.We quantify and model for the first time that relationship between bacterial abundance and atmospheric black carbon in Tibetan glaciers change over time based on GAM models.
基金supported by grants from the National Natural Science Foundation of China for Excellent Young Scientists Fund Program(No.42222105)the National Natural Science Foundation of China General Program(No.42171144)+1 种基金the Assessment of Ecosystem Carbon Stock and Turnover Patterns in Qinghai Province(No.2021-SFA7-1-1)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2021QZKK0100)。
文摘Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau(QTP)remains largely unknown.Here we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River(TTH)and May 2022 for Aerjin(ARJ),and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA gene.Our study revealed distinct bacterial communities,with significant differences in the relative abundances of Proteobacteria(P<0.05),Acidobacteriota(P<0.001),Bacteroidota(P<0.05),and Planctomycetota(P<0.001)between the active layer and the permafrost layer.More importantly,we found that interspecies interactions,including both positive and negative associations,were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly process.Our findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes,with interspecies interactions accounting for more than 58%and 63%of all assembly mechanisms,respectively.This is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP,highlighting the importance of considering interspecies interactions in future modeling efforts.Our work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0950000)the NSFC(Grant No.42201155+2 种基金4240114742201137)the State Key Laboratory of Cryospheric Science and Frozen Soil Engineering(CSFSE-ZQ-2410).
文摘The Yellow River(YR),China’s second-longest river,remains understudied regarding its greenhouse gases(GHGs)emissions,particularly the impacts of urban drainage ditches and wastewater treatment facilities on regional GHGs dynamics.This study investigated methane(CH_(4))and carbon dioxide(CO_(2))concentrations,fluxes and stable carbon isotopes(δ^(13)C-CH_(4)and δ^(13)C-CO_(2))across six main stream,three ditches,and one wastewater treatment site along the upper Lanzhou section of the YR,spanning from the urban entrance(36.176°N,103.449°E)to the exit of Lanzhou city(36.056°N,104.020°E).Measured CH_(4)diffusion fluxes in mainstem sites ranged from 0.01 to 2.58 mmol·m^(−2)·d^(−1)(mean:0.36 mmol·m^(−2)·d^(−1)),while ebullitive fluxes(gas bubbles)ranged from 0.01 to 18.89 mmol·m^(−2)·d^(−1)(mean:0.90 mmol·m^(−2)·d^(−1)).CO_(2)diffusion fluxes varied between 9.16–92.80 mmol·m^(−2)·d^(−1)(averaged:39.11 mmol·m^(−2)·d^(−1))at these locations.Ebullition(bubble)fluxes accounted for 53.1%±22.4%(range:9.0%to 98.4%)to total CH_(4)emissions(diffusion plus ebullition),with peak fluxes occurring during summer,indicating its significance as a CH_(4)transport mechanism.Notably,both diffusion CH_(4)and CO_(2)fluxes and ebullitive CH_(4)rates at ditch sites substantially exceeded those in mainstream reaches.The lowest CH_(4)and highest CO_(2)concentrations were observed at a wastewater treatment site,likely resulting from the removal of high organic loads.Acetoclastic methanogenesis—the process converting acetate-derived methyl groups to CH_(4)—was identified as the dominant production pathway in both mainstream and ditch environments.CH_(4)and CO_(2)flux magnitudes in the upper YR(Lanzhou section)were comparable to those observed in subtropical Yangtze River tributaries.These results demonstrate that anthropogenic influences significantly enhance CO_(2)/CH_(4)emissions,and the lateral exports of dissolved carbon(DIC and DOC)in the main stream site was quantified.,which cannot be overlooked.The findings emphasize the critical need to account for pronounced spatiotemporal variations in arid-region GHG fluxes to improve basin-scale estimates for the YR.
基金Second Tibetan Plateau Scientific Expedition and Research Program,No.2019QZKK0201National Natural Science Foundation of China,No.41801034,No.41971092Basic Research Program of Shanxi Province,No.202203021211258,No.202103021223248。
文摘Glaciers are considered to be‘climate-sensitive indicators'and‘solid reservoirs',and their changes significantly impact regional water security.The mass balance(MB)from 2011 to 2020 of the Qiyi Glacier in the northeast Tibetan Plateau is presented based on field observations.The glacier showed a persistent negative balance over 9 years of in-situ observations,with a mean MB of-0.51 m w.e.yr^(-1).The distributed energy-mass balance model was used for glacier MB reconstruction from 1980 to 2020.The daily meteorological data used in the model were from HAR v2 reanalysis data,with automatic weather stations located in the middle and upper parts of the glacier used for deviation correction.The average MB over the past 40 years of the Qiyi Glacier was-0.36 m w.e.yr^(-1)with the mass losses since the beginning of the 21st century,being greater than those in the past.The glacier runoff shows a significant increasing trend,contributing~81%of the downstream river runoff.The albedo disparity indicates that the net shortwave radiation is much higher in the ablation zone than in the accumulation zone,accelerating ablation-area expansion and glacier mass depletion.The MB of the Qiyi Glacier is more sensitive to temperature and incoming shortwave radiation variation than precipitation.The MB presented a non-linear reaction to the temperature and incoming shortwave radiation.Under future climate warming,the Qiyi Glacier will be increasingly likely to deviate from the equilibrium state,thereby exacerbating regional water balance risks.It is found that the mass losses of eastern glaciers are higher than those of western glaciers,indicating significant spatial heterogeneity that may be attributable to the lower altitude and smaller area distribution of the eastern glaciers.
基金supported by Key Collaborative Research Program of the Alliance of International Science Organizations(Grant no.ANSO-CR-KP-2021-04)the Key Program of National Natural Science Foundation of China(Grant no.42330410)。
文摘Glacial lakes,intimately linked to glacier termini,are crucial landscape features of the Qinghai-Xizang Plateau(QXP,Qinghai-Tibet Plateau)and the Arctic.Climate warming has accelerated glacier retreat and the rapid expansion of glacial lakes in both regions.Despite being typically considered harsh environments,these lakes serve as vital reservoirs for microbial biodiversity and carbon metabolism.In the face of climate change,glacial lake ecosystems over the QXP and the Arctic are undergoing unprecedentedtransformations.Thisopinioneditorial highlights the significance of conducting research and establishing long-term monitoring programs focused on microbial carbon metabolism in these glacial lakes.
基金supported by the National Natural Science Foundation of China for Excellent Young Scientists Fund Program(Grant No.42222105)the National Natural Science Foundation of China(Grant No.42421001)+1 种基金the Global Ocean Negative Carbon Emission(Global ONCE) Progrmthe Fundamental Research Funds for the Central Universities(Grant Nos.lzujbky-2022-ey08 and lzujbky-2023-eyt01)。
文摘Accelerated glacier melt driven by global warming is increasing nitrate(NO_(3)^(-)) fluxes to downstream ecosystems,thereby attracting wide attention to nitrogen cycling in glacial-fed regions.Proglacial lakes are closely connected to glaciers,and glacier-derived NO_(3)^(-)plays a critical role in regulating lake water NO_(3)^(-)concentrations.However,the relative contributions of glacier runoff(GR) versus in-lake biogeochemical processes to lake water NO_(3)^(-)remain poorly understood.This study uses measurements of NO_(3)^(-)concentrations and isotopic compositions(δ^(15)O-NO_(3)^(-),δ^(18)O-NO_(3)^(-),and Δ^(17)O-NO_(3)^(-))from the Qiangyong Glacier watershed on the Tibetan Plateau,combined with the MixSIAR model,to quantify the relative contributions of different NO_(3)^(-)sources.The results showed that GR was the dominant source to lake water NO_(3)^(-)during the melting season,accounting for 83%±5%,followed by in-lake microbial nitrification(MN) contributing 15%±4% and direct atmospheric deposition contributing 2%±2%.Further analysis reve aled that both GR input and internal lake processes controlled the seasonal variations of NO_(3)^(-)concentrations.During the early melt season,GR and enhanced in-lake nitrification increase NO_(3)^(-)concentrations,while sediment-mediated physical adsorption may contribute to their subsequent decrease.In contrast,during the non-melt season,NO_(3)^(-)concentrations gradually declined through microbial removal processes,such as denitrification and assimilation.This study quantified the relative contributions of GR and in-lake MN to lake NO_(3)^(-),highlighting that proglacial lakes are hotspots for nitrogen transformation.
基金the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0208)International Partnership Program of the Chinese Academy of Sciences(131C11KYSB20200029)Lhasa Earth System MultiDimension Observatory Network(LEMON)。
文摘Glacier-related slope failures,including ice avalanches,ice-rock avalanches,glacier collapses,and rock avalanches on glaciers,are generally characterized by large collapse volumes,solid-liquid phase transition,and high mobility[1].They are one of the major types of geo-hazards in high mountain areas.Glacier-related slope failures have cascading effects since they often evolve into glacial lake outburst floods(GLOFs),debris flows,and dammed lakes,which significantly prolong and amplify the impacts of the hazard.Tragic slope failures have cumulatively claimed more than tens of thousands of lives.For example,the 1962 and 1970 Huascaran events in the Peruvian Andes caused approximately 20,000 deaths[2],and the 2021 Chamoli ice-rock avalanche in the Indian Himalayas left more than 200 people dead or missing[3].
基金funded by the National Natural Science Foundation of China(Grant Nos.91851207,42171138)the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant No.2019QZKK0503).
文摘Background Microbial communities in different plant compartments are relatively independent entities.However,the influence of environmental factors on the microbial community in different compartments of periglacial plants remains unclear.In this study,we quantified the bacterial communities in the rhizosphere soil,as well as root and leaf endosphere compartments of a periglacial plant,Potentilla fruticosa var.albicans,using high-throughput DNA sequencing.Moreover,we evaluated the impacts of habitat types(glacier terminus zone,moraine ridge,and alpine meadow)on the bacterial community in different plant compartments of Potentilla fruticosa var.albicans.Results Our results showed that habitat type had a significant effect on the alpha diversity(Chao1 richness)of endophytic bacteria,but not on the rhizospheric bacteria.The community composition of rhizospheric and endophytic bacteria was significantly different across the three habitats,and habitat type had a greater effect on the endophytic bacteria than on rhizospheric bacteria.The contribution of rhizosphere soil to the root and leaf endophytes decreased with the transformation of habitats from glacier terminus zone to alpine meadow.In contrast,host selection pressure sequentially increased from the glacier terminus zone to the moraine ridge to the alpine meadow.Furthermore,we found that the bacterial co-occurrence network in the alpine meadow was more modular but had lower complexity and connectedness than that in the glacier terminus zone.The bacterial community was governed primarily by stochastic processes regardless of habitat type.Conclusion This study reveals that the diversity and composition of endophytic bacteria associated with Potentilla fruticosa var.albicans are more affected by habitat types than that of rhizospheric bacteria.Our study also demonstrates that the assembly patterns and co-occurrence patterns of bacterial communities associated with Potentilla fruticosa var.albicans vary by habitat type.These results advance the current understanding of community assembly and ecological interactions of microbial communities associated with periglacial plants.
基金supported by the National Natural Science Foundation of China(Grant Nos.42201147,U21A20176,42330410)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0503)。
文摘Microorganisms play an essential role in the glacier carbon cycle;how they transform organic matter in mountain glacial cryoconite remains to be studied.Here,we applied ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)and deep sequencing of 16S rRNA gene,to investigate the temporal microbial transformation of dissolved organic matter(DOM)of the Tibetan Plateau cryoconite.During the 60-day incubation,we found that DOM in cryoconite underwent a three-stage transformation,with decreasing bioavailability over time.The microbial community did not change much in the first week while degrading DOM molecules that were associated with higher H/C_(wa)and lower O/C_(wa).During days 15-30,DOM composition remained stable while microbial diversity increased.By day 60,the DOM was microbially converted into a higher state of recalcitrance,with higher values of aromatic index,O/C_(wa),and lower H/C_(wa),which contained molecules containing more heteroatoms.Cooperation among various microbial taxa,like Cyanobacteria,Bacteroidota,Gammaproteobacteria,Firmicutes,and Actinobacteriota,drove the DOM transformation in cryoconite.This study sheds light on the in-situ transformation of DOM composition meditated by microbial populations in cryoconite at a temporal scale,providing new insights into understanding the microbial roles in the glacier organic carbon transformation.
