Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Sugars in Snow, Their Sources, and Fate Related to Microbial Metabolism: A Review","authors":"Francesca Schivalocchi,&nbsp;Kara Sampsell,&nbsp;Christine Piot,&nbsp;Catherine Larose","doi":"10.1029/2024JG008720","DOIUrl":"10.1029/2024JG008720","url":null,"abstract":"<p>Snowpacks play a key role in local and regional biogeochemical cycles and impact surrounding ecosystems during snowmelt. While they do not serve as long-term carbon sinks like glaciers or permafrost, snowpacks temporarily store nutrients, pollutants, and microorganisms that can be released into surrounding ecosystems through meltwater. Active snow microorganisms within temporary snowpacks can contribute to carbon cycling through processes such as carbon fixation, respiration, and carbohydrate metabolism. In addition, snowpacks continuously receive atmospheric inputs, including carbohydrates from plants and microbes. These carbohydrates serve as indicators of biological and human activities. Factors like season, altitude, and location affect the carbohydrate composition, with sugars like glucose, sucrose, and mannitol linked to vegetation and microbial activity, while others, such as levoglucosan, mannosan, and galactosan, trace biomass burning events. Over time, snowpacks transform into firn and eventually ice, trapping airborne particles like carbohydrates. These preserved compounds in ice cores provide insights into past environmental conditions, including vegetation patterns and fire events. However, the current situation of rapid climate change threatens to disrupt these snowpack systems, underscoring the need for urgent investigation into the dynamics of carbohydrates and microbial activity. Thus, further research is crucial to unravel the biochemical processes within snowpacks and their implications for ecosystem dynamics. Field studies and experimental approaches will be fundamental in advancing our understanding of these complex and evolving systems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008720","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chlorination Cessation Alters Greenhouse Gas Dynamics in Artificial Urban Ponds","authors":"J. J. Montes-Pérez,&nbsp;P. Irusta,&nbsp;L. Cañas,&nbsp;F. Mejía,&nbsp;N. Pinaud-Brageot,&nbsp;B. Obrador,&nbsp;D. Puigserver,&nbsp;A. Millán,&nbsp;D. von Schiller","doi":"10.1029/2025JG008907","DOIUrl":"10.1029/2025JG008907","url":null,"abstract":"<p>Cities are facing an ecological challenge, and international policies are increasingly focused on implementing nature-based solutions to support this transition. In this context, the naturalization of artificial urban ponds (AUP) is a promising approach with proved benefits for biodiversity and human well-being. However, the naturalization of AUP may be accompanied by increased greenhouse gas (GHG) emissions. Here, we evaluated the effect of chlorination cessation, an essential step in the naturalization process, on GHG dynamics in AUP. Partial pressures of CO₂ (pCO₂), CH₄ (pCH₄), and N₂O (pN₂O) were measured in 41 artificial urban ponds (28 non-chlorinated and 13 chlorinated) in the city of Barcelona during winter and summer to assess: (a) the effect of chlorination treatment, (b) the effect of seasonality, and (c) the main drivers behind the partial pressures of these GHGs. Results show that although chlorination cessation increased pCH₄, it reduced pN₂O and had no significant effect on pCO₂. The main drivers of these patterns were naturalization, with factors related to primary production playing a major role; seasonality, with temperature as a key environmental variable; and groundwater legacy. Importantly, the net global warming potential (GWP), expressed as CO₂ equivalents, was not significantly higher in non-chlorinated ponds. These findings suggest that the naturalization of artificial water bodies could be a viable strategy to create more resilient cities without significantly increasing GHG emissions.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008907","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global Distribution and Biogeochemical Significance of Magnetotactic Bacteria in Deep-Sea Cold Seep Ecosystems","authors":"Kelei Zhu,&nbsp;Peiyu Liu,&nbsp;Yan Liu,&nbsp;Lulu Fu,&nbsp;Zengfeng Du,&nbsp;Rongrong Zhang,&nbsp;Jiawei Liu,&nbsp;Xin Zhang,&nbsp;Jinhua Li","doi":"10.1029/2025JG008888","DOIUrl":"10.1029/2025JG008888","url":null,"abstract":"<p>Magnetotactic bacteria (MTB) are distinguished by their ability to navigate along Earth's magnetic field and form diverse intracellular minerals, including nanocrystals of magnetite or greigite (i.e., magnetosomes). Although MTB are widespread in oxic-anoxic transition zones of aquatic systems worldwide, their presence in deep-sea environments has been less explored largely due to challenges in sampling and analytical methods. Here, we investigated deep-sea sediments from two active cold seeps in the South China Sea using metagenomic, magnetic, and microscopic techniques and extended our study to a global-scale metagenomic analysis of cold seep ecosystems. Our results reveal a wide distribution and high phylogenetic diversity of MTB in cold seeps worldwide with the phylum <i>Desulfobacterota</i> being particularly prevalent. Genome-scale metabolic reconstructions suggest that MTB contribute to iron and sulfur cycling potentially coupled with anaerobic methane oxidation in these deep-sea habitats. These findings not only broaden our understanding of MTB diversity and distribution in the deep sea but also underscore their important roles in biogeochemical processes within cold seep ecosystems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentary Evolution Influencing Methane Generation in Coastal Sediments of the Northern South China Sea","authors":"Wenqin Jiang,&nbsp;Weiguo Hou,&nbsp;Liancheng Hao,&nbsp;Binhua Cao,&nbsp;Youxu Dai,&nbsp;Xiaoyong Duan,&nbsp;Xingliang He,&nbsp;Maoying Liang,&nbsp;Xinyang Yu,&nbsp;Hailiang Dong","doi":"10.1029/2024JG008712","DOIUrl":"10.1029/2024JG008712","url":null,"abstract":"<p>Methane was intermittently detected along a 52-m sedimentary core from the coastal sediments of the northern South China Sea, providing an opportunity to better understand the sedimentary factors that influence methane generation. The sediment core was categorized into seven distinct sedimentary facies (U1–U7) based on different sedimentary characteristics at varying depths and dating test results (¹⁴C dating and optically stimulated luminescence dating). Sedimentary unit U4, located at a depth of 17.03–22.04 m below the seafloor (mbsf), was the primary layer for methane generation. This unit was found to be high in total organic carbon (TOC) and trace metals associated with methanogenesis, while the freshwater algal TOC source accounted for a higher proportion, which was favorable for biological methane generation. Analyses also showed that intense historical chemical weathering in the onshore catchment provided the key metallic elements, that is, Fe, Ni, Mo, and Co, during the deposition of Unit 4. Therefore, biological methane generation was jointly controlled by supplies of organic carbon and trace elements from chemical weathering.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144764057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dust Aerosols Enhance China's Gross Primary Productivity by Increasing Diffuse Radiation","authors":"Minghui Qi,&nbsp;Hongquan Song","doi":"10.1029/2024JG008578","DOIUrl":"10.1029/2024JG008578","url":null,"abstract":"<p>Dust aerosols play a crucial role in Earth's biogeochemical processes by modulating solar radiation and affecting terrestrial ecosystem productivity. In China, extensive arid and semi-arid regions contribute to high dust aerosol emissions, yet the long-term impact of dust aerosols on gross primary productivity (GPP) remains insufficiently quantified. This study coupled the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and the Joint UK Land Environment Simulator (JULES) to quantify the impact of dust aerosol radiative forcing on GPP in China's terrestrial ecosystems from 2000 to 2020. Results indicated that dust aerosols significantly alter surface solar radiation components by reducing direct radiation and enhancing diffuse radiation. The mean annual decrease in direct radiation due to dust aerosols was −8.2 ± 0.2 W m⁻², while the increase in diffuse radiation was 5.3 ± 0.1 W m⁻², leading to a net reduction in total surface solar radiation of around −2.9 W m⁻². These radiative changes resulted in an average annual increase in GPP of approximately 0.11 ± 0.024 Pg C yr⁻¹, accounting for around 2% of China's mean annual GPP of 6.44 ± 0.18 Pg C yr⁻¹ during the study period. The enhancement was particularly pronounced in regions with high dust aerosol loads, such as northwest China, and exhibited notable interannual variability. This study underscores the complex interactions between dust aerosols and terrestrial ecosystems, highlighting the importance of considering aerosol radiative effects in carbon cycle assessments and climate models.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144740532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the Atmospheric Microbial Ecosystem Through Theory, Bioenergetics, and Numerical Modeling: A Breath of Fresh Air for Aeromicrobiology","authors":"Eloi Martinez-Rabert,&nbsp;Laura Molares Moncayo,&nbsp;Elizabeth Trembath-Reichert,&nbsp;Rachael Lappan,&nbsp;Chris Greening,&nbsp;Jacqueline Goordial,&nbsp;James A. Bradley","doi":"10.1029/2025JG009071","DOIUrl":"10.1029/2025JG009071","url":null,"abstract":"<p>The atmosphere may constitute the Earth's largest microbial ecosystem, yet it remains the least understood. While microorganisms can persist and may even thrive in the polyextremes of the Earth's atmosphere, it is still unknown whether the atmosphere sustains an active microbial community. Despite growing awareness of the role of the aeromicrobiome in shaping global biogeography, epidemiology, and climate, fundamental questions about its metabolic activity and ecological significance remain unanswered. Here, we outline how theoretical approaches and numerical modeling tools provide powerful avenues to investigate the atmospheric microbial ecosystem, offering unique insights that complement experimental and observational-based studies and can overcome many of the challenges they face. We consider frameworks that integrate (a) theoretical considerations for microbial metabolism across a range of catabolic and anabolic processes, (b) microbial physiology and metabolic states, (c) thermodynamics and bioenergetics, (d) the chemical and physical conditions of the atmosphere and bioaerosols, (e) transport and residence time of microorganisms, and (f) bottom-up and top-down approaches. Theory and modeling-based investigations into the aeromicrobiome can generate and test theory and model-informed hypotheses, formulate mechanistic explanations of biological processes and observations, and inform targeted sampling strategies and experimentation. Together, these approaches bring us closer to determining whether the Earth's atmosphere is a <i>true</i> ecosystem—that is, a metabolically active community of organisms interacting with each other and with the environment. Advances in aeromicrobiology research brought about by theory and modeling can reveal significant insights into global biogeography, biogeochemical cycles, climate processes, and the limits for life.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009071","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144725430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of Dissolved Inorganic Carbon and CO2 Emission Controlled by Reservoir Regulation in the Yellow River","authors":"Jingbo Chen,&nbsp;Ming Liu,&nbsp;Xiaolin Ren,&nbsp;Xinying Che,&nbsp;Xueshi Sun,&nbsp;Dejiang Fan","doi":"10.1029/2025JG009021","DOIUrl":"10.1029/2025JG009021","url":null,"abstract":"<p>Reservoir construction has significantly modified the export and residence of riverine carbon in global rivers; however, various strategies of reservoir operation also introduce great uncertainties into aquatic carbon transformation and associated ecological effects. The material transport in the Yellow River (YR) is currently manipulated by water-sediment regulation scheme (WSRS) of Xiaolangdi Reservoir (XLDR), an effective strategy for managing sediment-laden rivers worldwide. Here, we investigated the spatiotemporal variability of water chemistry and dissolved inorganic carbon (DIC), from within XLDR to downstream YR. The results revealed that during the water regulation of XLDR, downstream DIC export was controlled by carbonate weathering but influenced by enhanced oxidation of dissolved organic carbon and soil CO₂ flushing. In contrast, during the sediment regulation, XLDR-released particulate organic carbon (POC) underwent significant mineralization within ∼400 km transport range, resulting in water acidification, hypoxia and extremely high CO₂ partial pressure. Furthermore, the substantial CO₂ production markedly intensified the carbonate weathering of XLDR-released sediments. Major cation and isotopic analyses indicated that 81%–82% of the downstream DIC production originated from OC mineralization, while 18%–19% contributed by carbonate mineral dissolution. As a strong CO₂ source, the WSRS significantly accelerated the CO₂ evasion along the downstream YR, which was estimated at 0.27 ± 0.05 Tg C within a month, corresponding to a 27% increase in annual downstream CO₂ efflux. The CO₂ evasion was primarily driven by the reservoir sediment release and OC mineralization. These findings highlight the crucial role of reservoir regulation in modulating riverine carbon transformation and emissions.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144725431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distinct Streamflow and Nutrient Export Dynamics in Wildfire-Impacted Nonperennial Streams in Central Coastal California","authors":"Lauren Giggy,&nbsp;Riley Barton,&nbsp;Sasha Wagner,&nbsp;Margaret Zimmer","doi":"10.1029/2024JG008553","DOIUrl":"10.1029/2024JG008553","url":null,"abstract":"<p>Wildfires impact water quality by altering nutrient supply and hydrology with changes often perceptible during the first major storm events. However, many factors influence water quality, including wildfire characteristics, weather patterns, and watershed properties. Such factors create challenges for predicting and mitigating water quality, highlighting the ongoing need for work across diverse hydroclimatic settings. The Santa Clara Unit Lightning Complex (SCU) Fire impacted two adjacent headwater catchments in central coastal California. Previous work showed that despite similar biophysical characteristics, the two catchments are hydrologically distinct with one catchment displaying flashier streamflow and higher dissolved organic carbon (DOC) concentrations likely driven by distinct bedrock. Although prefire data are not available, here we expand on this work with detailed observations of total dissolved nitrogen, phosphate (PO₄³⁻), and DOC concentrations and loads, over the first two years following the wildfire. We observed 2–13 times higher annual solute export from the catchment with flashier streamflow behavior. We hypothesize that elevated solute export occurred due to shallow hydrologic flow paths dominating runoff generation regardless of surface-level alterations from the wildfire. Additionally, we did not observe the highest solute concentrations during the first major storms following the wildfire. Instead, solute concentrations peaked during high-intensity rainfall in year two. This work showcases the importance of the hydrogeologic setting and hydrologic routing on solute export. Additionally, these results highlight challenges in predicting water quality responses in disturbed catchments and teasing apart the role of wildfire, ongoing drought, and high-intensity precipitation in semiarid climates.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008553","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linking Ecosystem CH4 Fluxes to Soil Profile CH4 Concentrations and Oxidation Rates: Year-Round Measurements and Drought Effects in a Danish Farmland","authors":"Peiyan Wang,&nbsp;Bingqian Zhao,&nbsp;Line Vinther Hansen,&nbsp;Wenxin Zhang,&nbsp;Louise H. Mortensen,&nbsp;Andreas Brændholt,&nbsp;Sander Bruun,&nbsp;Per Ambus,&nbsp;Bo Elberling","doi":"10.1029/2025JG008829","DOIUrl":"10.1029/2025JG008829","url":null,"abstract":"<p>Methane (CH₄) oxidation in well-drained soils is a key process contributing to the global CH₄ sink. Yet, temporal and depth-specific CH₄ oxidation is rarely described despite being critical for the surface net CH₄ uptake. Here, we linked year-round field observations of CH₄ fluxes in well-drained cultivated soils with subsurface CH₄ concentrations, laboratory incubations, and process-based modeling to uncover these mechanisms. Field observed CH₄ fluxes ranged from −0.43 to 0.19 mg CH₄ m⁻² day⁻¹ with an average of −0.15 ± 0.01 mg CH₄ m⁻² day⁻¹ over the year-round study period. Much higher CH₄ uptakes were observed in summer than in winter, indicating marked seasonal variations. Modeling using the CoupModel to simulate soil temperatures and water content as drivers, along with an analytic reaction-based model to simulate CH₄ fluxes, shows that the depth infiltration of atmospheric CH₄ is a critical parameter for defining a CH₄ oxidation reaction zone below the surface. The thickness of the reaction zone varied seasonally. Sensitivity tests of CH₄ concentrations and oxidation profiles in response to contrasting precipitation scenarios reveal that CH₄ oxidation during drought scenarios is increased at deeper depths due to higher CH₄ availability. However, CH₄ oxidation in near-surface layers decreased due to low soil water content, resulting in a significantly lower net surface CH₄ uptake. Our findings suggest that both the depth-specific CH₄ oxidation profile and net surface CH₄ fluxes will likely change under future warmer and drier periods.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008829","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shrub Expansion Can Counteract Carbon Losses From Warming Tundra","authors":"Theresia Yazbeck,&nbsp;Gil Bohrer,&nbsp;Oliver Sonnentag,&nbsp;Bo Qu,&nbsp;Matteo Detto,&nbsp;Gabriel Hould-Gosselin,&nbsp;Vincent Graveline,&nbsp;Haley Alcock,&nbsp;Bruno Lecavalier,&nbsp;Philip Marsh,&nbsp;Alex Cannon,&nbsp;William J. Riley,&nbsp;Qing Zhu,&nbsp;Fengming Yuan,&nbsp;Benjamin Sulman","doi":"10.1029/2024JG008721","DOIUrl":"10.1029/2024JG008721","url":null,"abstract":"<p>Arctic warming is causing substantial compositional, structural, and functional changes in tundra vegetation including shrub and tree-line expansion and densification. However, predicting the carbon trajectories of the changing Arctic is challenging due to interacting feedbacks between vegetation composition and structure, and surface characteristics. We conduct a sensitivity analysis of the current-date to 2100 projected surface energy fluxes, soil carbon pools, and CO₂ fluxes to different shrub expansion rates under future emission scenarios (intermediate—RCP4.5, and high—RCP8.5) using the Arctic-focused configuration of E3SM Land Model (ELM). We focus on Trail Valley Creek (TVC), an upland tundra site in the western Canadian Arctic, which is experiencing shrub densification and expansion. We find that shrub expansion did not significantly alter the modeled surface energy and water budgets. However, the carbon balance was sensitive to shrub expansion, which drove higher rates of carbon sequestration as a consequence of higher shrubification rates. Thus, at low shrub expansion rates, the site would become a carbon source, especially under RCP8.5, due to higher temperatures, which deepen the active layer and enhance soil respiration. At higher shrub expansion rates, TVC would become a net CO₂ sink under both Representative Concentration Pathway scenarios due to higher shrub productivity outweighing temperature-driven respiration increase. Our simulations highlight the effect of shrub expansion on Arctic ecosystem carbon fluxes and stocks. We predict that at TVC, shrubification rate would interact with climate change intensity to determine whether the site would become a carbon sink or source under projected future climate.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008721","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}