Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Nonlinear Interactions Between Solar-Induced Fluorescence, Atmospheric Demand, and Soil Moisture Constrain Ecosystem Evapotranspiration Estimation","authors":"Subhrasita Behera,&nbsp;Debsunder Dutta","doi":"10.1029/2026JG009892","DOIUrl":"https://doi.org/10.1029/2026JG009892","url":null,"abstract":"<p>Evapotranspiration (ET) links the terrestrial water and carbon cycles, yet its accurate estimation remains limited by simplified representations of plant-atmosphere interactions. Solar-induced chlorophyll fluorescence (SIF) has emerged as a promising physiological constraint on ET through its link to stomatal conductance, but current SIF-based semi-mechanistic models assume fixed, linear relationships that limit their applicability under variable environmental conditions. Here, we evaluate a widely used SIF-driven semi-mechanistic ET model against eddy covariance observations from 31 flux tower sites spanning eight plant functional types, and employ an interpretable machine learning (ML) framework with SHAP (SHapley Additive exPlanations) analysis to identify where these formulations become limiting. The performance gap widens markedly under environmental stress, with the semi-mechanistic model showing reduced skill under low soil moisture (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>R</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${R}^{2}$</annotation>\u0000 </semantics></math> = 0.53 vs. 0.70 for ML) and high vapor pressure deficit (VPD) (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>R</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${R}^{2}$</annotation>\u0000 </semantics></math> = 0.45 vs. 0.65), indicating that fixed conductance formulations fail where nonlinear physiological regulation intensifies. SHAP diagnostics reveal that SIF and VPD are the dominant predictors of ET but their influence is conditional, with SIF-ET coupling modulated by soil water content and VPD exhibiting threshold-dependent behavior. PM-ML analysis confirms that this limitation lies in the linear conductance formulation based on SIF, and global-scale validation confirms these patterns across vegetated land. These results demonstrate that nonlinear coupling between photosynthetic activity, atmospheric demand, and soil water availability represents a first-order control on ecosystem ET that current semi-mechanistic formulations cannot adequately capture, and that interaction-aware parameterizations of stomatal conductance are needed to reduce biases across ecosystems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148783539","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":"Global Grassland Patterns and Changes Revealed by Spatial Distribution of Poaceae Pollen","authors":"Lai-Zheng Jiao,&nbsp;Wen-Ping Yuan,&nbsp;David K. Ferguson,&nbsp;Wen-Li Chen,&nbsp;Yu-Fei Wang,&nbsp;Yi-Feng Yao","doi":"10.1029/2026JG010063","DOIUrl":"https://doi.org/10.1029/2026JG010063","url":null,"abstract":"<p>Grasslands are among the most important terrestrial ecosystems on Earth. Grasslands dominated by Poaceae are essential carbon pools and play a vital role in maintaining biodiversity, absorbing atmospheric CO₂ and delivering ecosystem services. Understanding the past, current and future distributions of grasslands is important for coping with grassland degradation, developing reasonable ecological protection strategies and predicting ecosystem functions. The abundant data on Poaceae pollen abundance (PA) from global surface sediments provide valuable insights into simulating current grassland distribution patterns and forecasting their future trajectories under climate change. We created a data set containing 16,372 records with both characteristic variables (including vascular plant richness, bioclimatic, soil and elevation variables) and Poaceae PA and used a random forest model to simulate the spatial distribution of Poaceae PA. Results show a significant difference in the distribution of Poaceae PA across continents, with regions of higher abundance (e.g., ∼10% in temperate regions and ∼40% in tropical regions) closely aligned with the distribution of grasslands. Furthermore, we project the distribution of grass PA under four future climate scenarios (SSP126, 245, 370, 585) and the changes of grasslands. We find that the grassland coverage will likely increase at the end of this century. In particular, the temperate grasslands in the Northern Hemisphere are expected to expand northwards based on all the scenarios, whereas the Amazon savannas will also expand, thus encroaching on rainforests. Our findings offer a new perspective for understanding the changes in grasslands and their future development for both the scientific community and policy-makers.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148754102","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":"Analysis of Arsenic, Cadmium, Chromium, and Lead Levels: Interplay of Climate, Soil, and Human Factors in Urban Gardens","authors":"Leah Kocian,&nbsp;Binayak P. Mohanty,&nbsp;Azita Sharif","doi":"10.1029/2025JG009448","DOIUrl":"https://doi.org/10.1029/2025JG009448","url":null,"abstract":"<p>Understanding the spatial distribution of heavy metals in urban gardens is essential for mitigating contamination risks and supporting safe urban agriculture. This study examines factors influencing heavy metal concentrations in garden soil across San Antonio, Dallas, and Houston. A total of 215 soil samples, collected at the surface and down to 30 cm, were analyzed using Inductively Coupled Plasma–Mass Spectrometry for nine heavy metals, including arsenic (<i>As</i>), chromium (<i>Cr</i>), cadmium (<i>Cd</i>), and lead (<i>Pb</i>), which are elements of environmental and health concern due to their potential toxicity and, in some cases, carcinogenic properties. Over half (55%) of the samples exceeded the Environmental Protection Agency residential soil threshold for <i>As</i> (0.68 ppm). To identify key drivers, we applied both multivariate linear regression and a generalized mixed graphical network model. While regression highlights independent relationships between variables, the network model comprehensively captures nonlinearly interconnected relationships across variables. It revealed strong links between <i>As</i> and total soil carbon, <i>Cd</i> and clay content, <i>Pb</i> and distance to city center, and <i>Cr</i> and proximity to Superfund sites. A random forest model, informed by the top predictors from the network analysis, achieved its best performance for <i>As</i> (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>R</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 <mo>=</mo>\u0000 <mn>0.54</mn>\u0000 </mrow>\u0000 <annotation> ${R}^{2}=0.54$</annotation>\u0000 </semantics></math>). A combined network model including all four metals emphasized distance to the city center and clay percentage as the most influential factors. The highest average concentrations occurred in gardens within five miles of the city center and in soils with &lt;15% clay. These findings highlight the major drivers of metal concentrations in urban garden soils within the study region.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009448","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148753527","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":"Siderophores Reshape Microbial Fe(III) Reduction and Arsenic Release From Iron (Oxyhydr)Oxides","authors":"Si Meng Li,&nbsp;Wei Xiu,&nbsp;Xi Yang Xu,&nbsp;Jin Xing Xie,&nbsp;Zhi Xin Fang,&nbsp;Di Zhang,&nbsp;Jonathan R. Lloyd,&nbsp;Andreas Kappler,&nbsp;Hua Ming Guo","doi":"10.1029/2026JG009686","DOIUrl":"https://doi.org/10.1029/2026JG009686","url":null,"abstract":"<p>High-arsenic (As) groundwater is a global environmental concern, with As release largely governed by microbial reductive dissolution of Fe(III) (oxyhydr)oxides. Dissolved organic matter (DOM) rich in Fe-complexing ligands can modify these reactions, yet its influence on Fe(III) (oxyhydr)oxides transformation and associated As mobility remains poorly constrained. Here, we investigated the microbial reduction of As-bearing goethite by <i>Shewanella oneidensis</i> MR-1 in the presence of the hydroxamate siderophore desferrioxamine B (DFOB), used as a model strong Fe-complexing organic ligand, Luria–Bertani rather than a compositional analogue of bulk DOM. Results showed that DFOB markedly enhanced microbial Fe(III) reduction, increasing initial reduction rates by up to 70% and total Fe(II) production by 24% relative to MR-1-only controls. This acceleration stemmed from DFOB-facilitated Fe(III) complexation and improved electron-transfer interactions between MR-1 and goethite. Arsenic release occurred in all treatments and was positively correlated with the amount of reacted Fe (dissolved plus reduced Fe), indicating coupled Fe-As redox cycling. Despite stimulating Fe(III) reduction, DFOB did not promote additional As release, with MR-1-DFOB treatments exhibiting As mobilization similar to MR-1-only controls. This constrained As release was likely associated with DFOB-mediated redistribution of biogenic Fe(II) into solid-associated Fe pools and secondary Fe-rich phases, including locally observed nano-magnetite, minor siderite, and possibly poorly crystalline Fe phases, which may have contributed to As retention through adsorption and coprecipitation. These results reveal that DOM rich in Fe-complexing ligands, such as siderophores, can promote the formation of As-sequestering Fe-mineral phases, uncovering an unrecognized control on Fe-As interactions that may shape groundwater As mobilization.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148753232","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":"Dynamic Interplay Between Biogenic Fe(III) (Oxyhydr)Oxides and Microbial Reduction Pathways Governs Arsenic Mobilization","authors":"Si Meng Li,&nbsp;Wen Jie Yuan,&nbsp;Wei Xiu,&nbsp;Xiao Nuo Yu,&nbsp;Di Zhang,&nbsp;Tian Tian Ke,&nbsp;Zhi Xin Fang,&nbsp;Guang Yao Liu,&nbsp;David A. Polya,&nbsp;Jonathan R. Lloyd,&nbsp;Hua Ming Guo","doi":"10.1029/2026JG009874","DOIUrl":"https://doi.org/10.1029/2026JG009874","url":null,"abstract":"<p>Microbial reductive dissolution of As-bearing Fe(III) (oxyhydr)oxides is a primary mechanism of arsenic (As) mobilization in reducing aquifers; however, the relative contributions of mineral bioreactivity and microbial metabolic pathways remain insufficiently quantified. Here, we compared Fe(III)-reducing bacteria (<i>Shewanella oneidensis</i> MR-1 and <i>Geobacter sulfurreducens</i>) with a bacterium capable of both As(V) and Fe(III) reduction (<i>Clostridium</i> sp. anHT01, isolated from a high As aquifer sediment from Inner Mongolia) to elucidate Fe and As release kinetics from As(V)-bearing biogenic ferrihydrite-goethite (Bio-GF) and lepidocrocite (Bio-Lp) under bicarbonate-buffered reducing conditions. Biogenic mineralogy primarily governed the extent of Fe(III) reduction, with Bio-GF exhibiting higher bioreactivity than Bio-Lp, but did not dictate net As mobilization. In contrast, microbial metabolic pathways controlled the temporal relationship between Fe reduction and As release. Systems with active As(V) reduction exhibited delayed Fe(III) reduction yet rapid As(III) release, resulting in elevated As_released/Fe_released ratios and net As mobilization during the Fe-reduction lag phase. Secondary Fe(II) minerals modulated As partitioning and retention but did not govern the onset of As mobilization. Together, these results demonstrate that As mobilization during microbial reduction of biogenic Fe(III) (oxyhydr)oxides is jointly governed by mineral bioreactivity and microbially mediated Fe-As release relationships, providing a mechanistic basis for improving the prediction of As behavior in reducing aquifer systems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148753233","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":"Unveiling Drought-Induced Algal Blooms in Tidal Freshwater Zones With an Interpretable Bloom Risk Index","authors":"Wenfan Wu,&nbsp;Zhengui Wang,&nbsp;Jian Shen,&nbsp;Y. Joseph Zhang,&nbsp;Jeremy M. Testa,&nbsp;Richard Tian,&nbsp;Lewis C. Linker","doi":"10.1029/2026JG009712","DOIUrl":"https://doi.org/10.1029/2026JG009712","url":null,"abstract":"<p>Tidal Freshwater Zones (TFZs), typically situated in the upper reaches of estuaries, are highly dynamic ecosystems where hydrodynamic, biogeochemical, and anthropogenic processes strongly interact. This high complexity, together with increasing climate extremes, poses substantial challenges for diagnosing algal bloom dynamics in these regions. Using the TFZs of the Patuxent River (USA) as a case study, we examined a series of rare and intense algal blooms triggered by a severe drought in summer 2007, utilizing extensive in situ observations and an interpretable bloom risk index. The index effectively reproduced observed chlorophyll-<i>a</i> variability in the TFZs across intraseasonal, seasonal, and interannual timescales, demonstrating that drought modulates the algal blooms via the synergistic responses of atmospheric, hydrological, and anthropogenic drivers. During the 2007 drought, precipitation deficits reduced cloud cover, thereby increasing downward solar radiation, while reduced river discharge lowered water turbidity and prolonged water residence time. Water temperature also exhibits a pronounced positive anomaly. In addition, reduced dilution capacity under low-flow conditions amplified the influence of nutrient inputs from the upstream wastewater treatment plant, sustaining sufficient phosphorous availability in the study area. These drought-induced synergistic responses collectively promoted rapid phytoplankton growth at an early stage. As the drought persisted, however, the seasonal decline in solar radiation, along with the decreasing water temperature, largely inhibited the bloom intensity at the late stage, despite the exceptionally long residence time then. This study suggests that TFZs are exposed to multi-faceted stressors from climate extremes, and the proposed index also offers an effective tool for ecological management in estuarine ecosystems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JG009712","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148752821","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":"Organic Carbon Loading Governs Ecological Structure and Nitrogen Cycling in a Tropical Closed-Basin Lake Over the Late Holocene","authors":"Abdur Rahman,&nbsp;Hsien-Hsiao Tsai,&nbsp;Yuan-Pin Chang,&nbsp;Ranjan Kumar Mohanty,&nbsp;Siddhartha Sarkar,&nbsp;Chen-Tung Arthur Chen,&nbsp;Liang-Chi Wang","doi":"10.1029/2026JG009897","DOIUrl":"https://doi.org/10.1029/2026JG009897","url":null,"abstract":"<p>This study reconstructs late Holocene changes in the biogeochemical cycling of Jiaming Lake, eastern Taiwan using diatom assemblages, stable carbon and nitrogen isotopes (δ¹³C, δ¹⁵N), total organic carbon (C) and nitrogen (N) contents, and C/N ratios. Elevated C/N ratios and more negative δ¹³C values indicate wetter intervals (3,800–2,400 and 1,600–800 cal yr BP) characterized by increased input of terrestrial organic matter driven by enhanced runoff. In contrast, lower C/N ratios and less negative δ¹³C values reflect reduced terrestrial input and a greater relative contribution from aquatic primary production, consistent with decreased runoff and relatively drier climatic conditions during 2400–1600 and 800–300 cal yr BP. The persistent dominance of acidophilic diatom taxa indicates that lake-water conditions remained acidic over the past 3,800 cal yr BP, although reorganization of diatom assemblages occurred after 2,400 cal yr BP. These long-term ecological changes were closely linked to variations in organic C loading and associated shifts in N-cycling. During the wetter intervals, variations in organic C loading corresponded to differences in the intensity of anaerobic N-loss processes, likely including denitrification, DNRA, and anammox. In the earlier wet phase, the strong expression of anaerobic N-loss cannot be attributed solely to climate-driven organic carbon input to the lake. Archaeological records from eastern Taiwan indicate elevated regional human activity during this period, suggesting that anthropogenic influences may have contributed to the observed N-cycle dynamics. On the other hand, low organic C loading during the drier phases shifts N transformation pathways toward aerobic nitrification processes along with water-column mixing.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148752456","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":"Contrasting N Form Uptake Strategies of Alpine Plant Functional Groups Under N and P Enrichment","authors":"Chengling Yu,&nbsp;Xingliang Xu,&nbsp;Lili Jiang,&nbsp;Min Liu,&nbsp;Zhe Pang,&nbsp;Rui Pang,&nbsp;Zongsong Wang,&nbsp;Weiwai Zhao,&nbsp;Yanfen Wang","doi":"10.1029/2025JG009381","DOIUrl":"https://doi.org/10.1029/2025JG009381","url":null,"abstract":"<p>Understanding how plant functional groups respond to nutrient enrichment is essential for predicting alpine ecosystem dynamics under global change. Although biomass responses to nitrogen (N) and phosphorus (P) additions have been widely investigated, shifts in plant N uptake strategies among functional groups under nutrient enrichment remain poorly understood. We conducted a 7-year field experiment in an alpine grassland on the Qinghai-Tibetan Plateau using factorial N (0, 7.5, 15 g m⁻² yr⁻¹; N0, N1, N2) and P (0, 7.5, 15 g m⁻² yr⁻¹; P0, P1, P2) additions. To evaluate N-form uptake, we performed an in situ ¹⁵N labeling experiment using ammonium (NH₄⁺), nitrate (NO₃⁻) and glycine, and collected plant and soil samples 4 h after label application. NH₄⁺ was the dominant N source taken up by the plant community, with community-level uptake enhanced under moderate N (N1) but showing no further increase under higher nutrient inputs, indicating a non-linear threshold response. Functional groups exhibited contrasting strategies: sedges primarily preferred NH₄⁺ and responded most strongly to N1, grasses showed plastic uptake across treatments, and forbs increased NO₃⁻ and glycine-derived N uptake under N2P2, suggesting niche differentiation. Plant N uptake was weakly related to soil physicochemical variables but strongly associated with plant N:P stoichiometry, underscoring the predominance of intrinsic plant traits over soil conditions in driving functional group N uptake. Our results suggest that long-term nutrient enrichment alters N-form uptake partitioning among functional groups, with potential consequences for niche complementarity and community composition in alpine grasslands.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148752413","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":"Warming Drives Large-Scale Shifts in Post-Disturbance Vegetation Dynamics and Expansion of Deciduous Trees in the Boreal Forest in a Dynamic Vegetation Model","authors":"L. S. Layritz,&nbsp;M. Anand,&nbsp;J. E. Kim,&nbsp;B. F. Meyer,&nbsp;K. Gregor,&nbsp;T. A. M. Pugh,&nbsp;C. Boettiger,&nbsp;A. Buras,&nbsp;A. Rammig","doi":"10.1029/2025JG009176","DOIUrl":"https://doi.org/10.1029/2025JG009176","url":null,"abstract":"<p>The intensification of disturbance regimes due to climate change is a growing concern in boreal forests, yet the long-term consequences for forest recovery remain poorly understood, as boreal successional dynamics unfold over a century or longer and exceed the length of available observational records. To overcome this research gap we use the dynamic vegetation model LPJ-GUESS to investigate future climate change impacts on boreal successional dynamics over the 21st and 22nd centuries. We first confirm that LPJ-GUESS reproduces historic patterns of post-disturbance recovery. We then show that under future warming, deciduous transients become more frequent, longer, and more pronounced due to a temperature-mediated shift in competitive balance emerging in LPJ-GUESS. Using a random forest framework, we find that the long-term recovery pathway can be predicted with 90% accuracy from vegetation and environmental conditions in the first decade after disturbance alone. This supports the hypothesis that the changes in post-disturbance recruitment currently observed in boreal forests are an indicator of more long-lasting changes in vegetation composition in the future. While we find no evidence for permanent shifts toward deciduous tree cover in LPJ-GUESS, the combination of prolonged deciduous transients and more frequent disturbances makes an increase in deciduous tree cover a likely future scenario.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009176","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148752622","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":"Carbon, Water, and Energy Flux Dynamics in Different Cropping Systems in the Great Lakes Region","authors":"M. Altaf Arain,&nbsp;Nur Hussain,&nbsp;Liam Kreibich,&nbsp;Jason Brodeur,&nbsp;Zoran Nesic","doi":"10.1029/2025JG009647","DOIUrl":"https://doi.org/10.1029/2025JG009647","url":null,"abstract":"<p>This study examined carbon (C), water, and energy exchanges across different cropping systems in the Great Lakes region using eddy covariance (EC) fluxes from an agricultural flux tower site (CA-TPA) in southern Ontario, Canada. The site was cultivated with corn in 2020 and 2021, sweet potato in 2022, and tobacco in 2023. The site was a strong C sink during the corn years, with annual net ecosystem productivity (NEP) values of 538 ± 4.9 and 301 ± 3.7 g C m⁻² yr⁻¹ in 2020 and 2021, respectively. In contrast, it became a C source in 2022 under sweet potato, exhibiting an annual NEP of −86 ± 2.1 g C m⁻² yr⁻¹. Under tobacco in 2023, the site transitioned to a weak carbon sink, with an annual NEP of 29 ± 1.6 g C m⁻² yr⁻¹. Crop yield (CY) was 537 and 491 g C m² for corn in 2020 and 2021, respectively, 118 g C m² for sweet potato in 2022, and 124 g C m² for tobacco in 2023. It resulted in an annual net ecosystem carbon balance (NECB) of 1, −190, −205, and −95 g C m² yr⁻¹ for 2020, 2021, 2022, and 2023, respectively, indicating an overall net C loss from all three cropping systems after accounting for harvested biomass. Annual evapotranspiration (ET) totals were 661, 727, 745, and 722 mm yr⁻¹ for 2020–2023, accounting for approximately 58%, 72%, 78%, and 74% of annual precipitation. The study results provide insights to support climate-smart crop management practices in the region.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009647","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148617342","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}