Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Increased Salinity Constrains the Priming Effect of SOM Decomposition by Shifting Microbial Carbon Preferences: A Microcosm Study in a Typical Coastal Wetland","authors":"Guangliang Zhang,&nbsp;Junhong Bai,&nbsp;Wei Wang,&nbsp;Yaqi Wang,&nbsp;Yue Liu,&nbsp;Zhe Liu,&nbsp;Yujia Zhai,&nbsp;Shengrui Wang","doi":"10.1029/2024JG008655","DOIUrl":"https://doi.org/10.1029/2024JG008655","url":null,"abstract":"<p>The introduction of exogenous straw from exotic plants can significantly impact the carbon sequestration in coastal vegetated ecosystems (CVEs) through the priming effect (PE) on the native soil organic matter (SOM) decomposition. Salt accumulation resulting from wetland drying and sea level rise is a critical factor governing carbon dynamics in CVE soils. However, our understanding of the relationship between SOM decomposition and the PE under increasing salt stress remains limited in CVEs. In this study, we conducted a microcosm experiment with a full factorial design with salt stress and straw input to investigate the intensity of the PE and its contribution to SOM decomposition. Our findings revealed that salt stress reduced the rate of SOM decomposition, significantly impacting the intensity of the PE throughout the incubation period. Straw input induced a strong positive PE in the early stage under low salt stress, whereas high salt stress led to a markedly negative PE in the later stage of incubation. Salt stress and exogenous straw input collectively resulted in a notable decrease in soil prokaryotic diversity with salt-tolerant and oligotrophic microbial species playing pivotal roles in highly saline and SOM-deficient soils, accompanied by a relatively high fungi to bacteria ratio. The microbial co-occurrence network demonstrated a relatively high degree of modularity under nutrient-poor conditions, suggesting a cometabolic driving force for SOM decomposition. This study elucidates the response of SOM decomposition induced by exogenous straw input under salt stress and highlights the influence of microbial metabolic strategies on the SOM turnover in CVEs.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213828","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":"Data-Driven Modeling of 4D Ocean and Coastal Acidification in the Massachusetts and Cape Cod Bays From Surface Measurements","authors":"B. Champenois,&nbsp;C. Bastidas,&nbsp;B. LaBash,&nbsp;T. P. Sapsis","doi":"10.1029/2024JG008465","DOIUrl":"https://doi.org/10.1029/2024JG008465","url":null,"abstract":"&lt;p&gt;A significant portion of atmospheric &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; emissions is absorbed by the ocean, resulting in acidified seawater and altered carbonate composition that is harmful to marine life. Despite detrimental effects, assessing ocean and coastal acidification (OCA) is difficult due to the scarcity of in situ measurements and the high costs of computational modeling. We develop a parsimonious data-driven framework to model indicators of OCA and test it in the Massachusetts Bay and Stellwagen Bank, a region with fishing and tourism industries affected by OCA. First, we trained a neural network to predict in-depth fields for temperature and salinity &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;x&lt;/mi&gt;\u0000 &lt;mo&gt;,&lt;/mo&gt;\u0000 &lt;mi&gt;y&lt;/mi&gt;\u0000 &lt;mo&gt;,&lt;/mo&gt;\u0000 &lt;mi&gt;z&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $(x,y,z)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; using surface quantities from satellites and in situ measurements &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;x&lt;/mi&gt;\u0000 &lt;mo&gt;,&lt;/mo&gt;\u0000 &lt;mi&gt;y&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $(x,y)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. The relationship between 2D surface and 3D properties is captured through the in-depth modes and coefficients obtained from principal component analysis applied to a high-resolution historical reanalysis data set. Next, we used Bayesian regression methods to estimate region-specific relationships for in-depth total alkalinity (TA), dissolved inorganic carbon (DIC), and aragonite saturation state &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Ω&lt;/mi&gt;\u0000 &lt;mtext&gt;Ar&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({{Omega }}_{text{Ar}}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; as functions of temperature, salinity, and chlorophyll. Lastly, 4D daily field predictions are generated from surface measurements with a spatial resolution of 4 km horizontally and 45 sigma levels vertically. The model's performance is evaluated usin","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008465","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206748","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":"Natural H2 and Sulfate Production via Radiolysis in Low Porosity and Permeability Crystalline Rocks","authors":"Peter M. Higgins,&nbsp;Min Song,&nbsp;Oliver Warr,&nbsp;Barbara Sherwood Lollar","doi":"10.1029/2025JG008863","DOIUrl":"https://doi.org/10.1029/2025JG008863","url":null,"abstract":"<p>Natural hydrogen (H₂) is a candidate low-carbon energy source for society and sustains microbial ecosystems when coupled with oxidants (e.g., sulfate). In crystalline rock settings, water-rock interactions, including radiolysis, generate both H₂ and sulfate, but quantifying their production rates remains challenging when porosity and permeability are low. This study employs a Monte Carlo approach to estimate H₂ and sulfate production via radiolysis in the Revell batholith (Ontario, Canada), a well characterized site which is representative of hydrogeologically tight conditions. Results are then compared to estimates from a similarly isolated, but more fractured site at Kidd Creek (Ontario, Canada) to examine the spectrum of elemental cycling and habitability that may exist in these globally widespread settings. At Revell, production rates for both H₂ and sulfate are substantially lower than for Kidd Creek. Revell's most probable H₂ production rate is estimated at 1.6 nmol m⁻³ rock yr⁻¹, approximately half that of Kidd Creek, and Revell's sulfate production is 10²–10⁶-fold lower. These differences are primarily driven by Revell's lower porosity and sulfide concentrations, respectively. While statistical analyses suggest a small theoretical probability of low levels of biological activity, Revell's potential for sulfate-supported habitability is calculated to be among the lowest observed in subsurface settings globally. This study demonstrates a framework for quantifying potential H₂ and sulfate production in settings where direct sampling of biomass, gas, and fluid is not feasible. It can be applied to investigations of the Earth's deep biosphere, geologic repositories, economic H₂ exploration, and habitability for other planets and moons.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008863","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179357","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":"Characteristics of Carbon Sink and the Influencing Factors in Ngoring Lake, Qinghai-Tibet Plateau","authors":"Mengxiao Wang,&nbsp;Lijuan Wen,&nbsp;Zhaoguo Li,&nbsp;Xianhong Meng,&nbsp;Dongsheng Su","doi":"10.1029/2024JG008550","DOIUrl":"https://doi.org/10.1029/2024JG008550","url":null,"abstract":"<p>Continuous annual carbon dioxide (CO₂) flux, encompassing ice-covered periods, has been monitored in Ngoring Lake, the largest freshwater lake on the Qinghai-Tibet Plateau (QTP). By utilizing continuous eddy system data, the characteristics and mechanisms influencing CO₂ flux at various temporal scales in the lake were investigated. Findings revealed that Ngoring Lake was predominantly acting as a carbon sink year-round. The average annual CO₂ sink value was maximum in 2016, about −1.46 g C m⁻² d⁻¹. There were two CO₂ absorption peaks in spring and autumn, respectively. The multi-year average monthly mean CO₂ absorption peaks occurred in April (−1.70 g C m⁻² d⁻¹) and October (−1.75 g C m⁻² d⁻¹), respectively. These peaks were associated with the freeze-thaw process and were caused by the mixing process due to water cooling. The continuous warming during the ice-covered period led to a high-water temperature, and the maximum value reached 6°C. In spring, mixing occurred upon ice melt, and the water temperature at 2 m depth decreased rapidly to 4°C because it was about 5°C higher than the air temperature. In autumn, cooling and mixing were induced by decreasing air and water temperatures alongside strong wind. These cooling processes facilitated significant CO₂ absorption. The CO₂ absorption process was controlled by wind speed, lake ice, lake mixing and stratification.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179360","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 Temperature Sensitivity of Boreal Forest Productivity in North America and Eurasia","authors":"D. Muccio,&nbsp;G. Keppel-Aleks,&nbsp;N. Parazoo","doi":"10.1029/2024JG008634","DOIUrl":"https://doi.org/10.1029/2024JG008634","url":null,"abstract":"<p>The seasonal amplitude of atmospheric carbon dioxide (CO₂) has increased by as much as 50% over the last 6 decades, suggesting changes to the Arctic-boreal carbon cycle. Some of this increase is due to increasing seasonality of net ecosystem exchange in boreal and arctic ecosystems, although the mechanisms are still uncertain. For example, it is unknown how much of the increase is due to increases in gross primary productivity (GPP) during the growing season. Such an increase could be attributable either to global-scale CO₂ fertilization or to regional climate impacts, which may vary across the boreal zone. In this study, we use a global, spatially, and temporally contiguous solar-induced chlorophyll fluorescence (CSIF) data product from 2001 to 2019 (0.05°, 4-day resolution) to identify spatial, interannual, and long-term sensitivities (linear slopes) of GPP to temperature across boreal forests in Eurasia and North America. Across all evergreen needleleaf regions, spatial sensitivities of CSIF to temperature are stronger in magnitude when compared to interannual sensitivities, suggesting that there are limitations when performing space for time substitutions. We find that Eurasian forests generally have the strongest spatial sensitivity to temperature. Eurasian deciduous needleleaf forests show the highest growing season mean interannual sensitivity to temperature variations. Although all regions show a positive spatial and interannual relationship between productivity and temperature, in western North America, long-term warming may be curbing productivity gains. Our results suggest that Eurasian and North American boreal forests may show divergent trends as climate continues to warm.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008634","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171230","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":"Determining Spatially Variable Peat Depths of an Alpine Peatland in the Qinghai-Tibet Plateau","authors":"Peng Gao,&nbsp;Zhuohong Li,&nbsp;Anwesha Majumdar,&nbsp;Zhiwei Li","doi":"10.1029/2024JG008713","DOIUrl":"https://doi.org/10.1029/2024JG008713","url":null,"abstract":"<p>Understanding peat depths is crucial for assessing carbon dynamics within peatlands. However, accurately estimating peat depths across large areas remains challenging. In this study, we developed a novel approach integrating a machine-learning based regression modeling with an optimized field sampling strategy to predict spatially variable peat depths across the Black River (BR) watershed with an area exceeding 4,600 km² within the Zoige basin of the Qinghai-Tibet Plateau. Using the key controlling factors (elevation, slope, soil organic carbon, and soil bulk density), we created a high resolution (13 m) digital map depicting the spatial distribution of peat depths throughout the BR watershed. We validated the accuracy of predicted peat depths through comparison with field measurements and revealed that slope is the dominant control in determining peat depths. The resulting map highlights that deep peat deposits typically cluster in upslope sections and areas of higher elevations. The total peat carbon stock within the study area amounts to approximately 4.195 Pg C, following a spatial pattern similar to peat depths but with greater concentration in three specific counties. These high-resolution peat depth and peat carbon maps provide valuable insights for effective peatland management in these vulnerable alpine ecosystems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171778","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":"Constraining Light-Driven Plasticity in Leaf Traits With Observations Improves the Prediction of Tropical Forest Demography, Structure, and Biomass Dynamics","authors":"Yixin Ma,&nbsp;Paul R. Moorcroft,&nbsp;S. Joseph Wright,&nbsp;Alistair Rogers,&nbsp;Julien Lamour,&nbsp;Kenneth J. Davidson,&nbsp;Shawn P. Serbin,&nbsp;Matteo Detto,&nbsp;Xiangtao Xu","doi":"10.1029/2025JG008814","DOIUrl":"https://doi.org/10.1029/2025JG008814","url":null,"abstract":"<p>Predicting tropical tree demography is a key challenge in understanding the future dynamics of tropical forests. Although demographic processes are known to be regulated by leaf trait diversity, only the effect of inter-specific trait variation has been evaluated, and it remains unclear as to what degree the intra-specific trait plasticity across light gradients (hereafter light plasticity) regulates tree demography, and how this will further shape long-term community and ecosystem dynamics. By combining in situ trait measurements and forest census data with a terrestrial biosphere model, we evaluated the impact of observation-constrained light plasticity on demography, forest structure, and biomass dynamics in a Panamanian tropical moist forest. Modeled leaf physiological traits vary across and within plant functional types (PFT), which represent the inter-specific trait variation and the intra-specific light plasticity, respectively. The simulation using three non-plastic PFTs underestimated 20-year average understory growth rates by 41%, leading to a biased forest size structure and leaf area profile, and a 44% underestimate in long-term biomass. The simulation using three plastic PFTs generated accurate understory growth rates, resulting in a realistic forest structure and a smaller biomass underestimate of 15%. Expanding simulated trait diversity using 18 nonplastic PFTs similarly improved the prediction of demography and biomass. However, only the plasticity-enabled model predicted realistic long-term PFT composition and within-canopy trait profiles. Our results highlight the distinct role of light plasticity in regulating forest dynamics that cannot be replaced by inter-specific trait diversity. Accurately representing light plasticity is thus crucial for trait-based prediction of tropical forest dynamics.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171706","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":"Trace Metal Effluxes From Peruvian Shelf Sediments Constrained in Parallel by Benthic Lander Mounted Pumps and Pelagic Rosette Sampling","authors":"Te Liu,&nbsp;Anna Plass,&nbsp;Martha Gledhill,&nbsp;Florian Scholz,&nbsp;Eric P. Achterberg,&nbsp;Mark J. Hopwood","doi":"10.1029/2024JG008583","DOIUrl":"https://doi.org/10.1029/2024JG008583","url":null,"abstract":"<p>Shelf sediments receive trace metals (TM) from sinking particles and return TMs to the water column via dissolved effluxes and resuspension events. For dissolved redox sensitive elements such as iron (Fe), shelf sediments underneath oxygen minimum zones are typically a major source to the water column. However, quantifying the associated dissolved fluxes is methodologically challenging. During an oceanographic campaign to the Peruvian shelf, we deployed benthic landers fitted with in situ lander pumps and a GEOTRACES compliant sampling rosette system. By overlapping the deployment of these instruments, we aimed to quantitatively assess the known deficiencies in assessment of TM concentrations and fluxes close to the seafloor. Across 7 locations over the Peruvian shelf, we observed consistent spatial trends between the two approaches with &lt;20% difference for measured dissolved copper, nickel, and silicic acid concentrations. Dissolved Fe gradients were however notably stronger near the seafloor. Samples from in situ lander pumps typically suggested much higher concentrations at 0.5–5 m from the seafloor than samples from the rosette system deployed within 2 m of the seafloor. Similarly, estimated diffusive dissolved Fe (dFe) fluxes were a factor of 30–570× higher when derived using the concentration gradient from the in situ lander pumps over the inner/midshelf. The calculated residence time of dFe thus varies markedly with a range from 5 days to 7 years depending on how the benthic flux is constrained. These differences largely reflect the rapid attenuation of dFe concentrations from benthic effluxes by both scavenging and dilution on spatial scales of ∼0.1–10 m.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008583","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135820","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":"Data Assimilation of Solar-Induced Chlorophyll Fluorescence Improves Gross Primary Production Simulation by a Process-Based VISIT-SIF Model in a Rice Paddy","authors":"Liangxian Fan,&nbsp;Tomomichi Kato,&nbsp;Tatsuya Miyauchi,&nbsp;Kanokrat Buareal,&nbsp;Tomoki Morozumi,&nbsp;Keisuke Ono","doi":"10.1029/2024JG008280","DOIUrl":"https://doi.org/10.1029/2024JG008280","url":null,"abstract":"<p>Simulating gross primary production (GPP) is a key objective of terrestrial ecosystem models, and many studies have shown that solar-induced chlorophyll fluorescence (SIF) is a reliable proxy for GPP. This study combines SIF data with a process-based vegetation integrative simulator for trace gases (VISIT-SIF) model to enhance GPP simulations in the Mase rice paddy field in Tsukuba, Japan. Using data assimilation techniques (Bayesian optimization) with both ground-based SIF data and satellite-derived SIF (CSIF) (both from 29 June 2019 to 10 September 2020), we optimized key model parameters and improved the simulation of GPP. Sensitivity analysis via SHapley Additive exPlanations (SHAP) revealed that the maximum rate of carboxylation (Vcamx)-related parameters significantly influence GPP, while the absorbed photosynthetically active radiation (APAR)-related parameters are more critical for SIF modeling. Model optimization resulted in substantial performance improvements, particularly in simulating GPP at half-hourly and daily scales. For half-hourly results, the <i>R</i>² values of SIF improved from 0.37 to 0.60, and the relative error decreased from 124.21% to 63.39%, but the model went from underestimation to overestimation; for GPP, <i>R</i>² values improved from 0.47 to 0.68, relative error decreased from 150.00% to 47.85%, and the model's tendency to underestimate has been mitigated. At the daily scale, model simulations demonstrated higher <i>R</i>² values and lower relative errors than observations. Using the CSIF data set also improved the model but was less effective than densely measured ground SIF. Further, we explored the relationship between SIF and GPP on half-hourly scale, daily scale, and weekly scale and found that the larger the time scale, the stronger the linear relationship of SIF-GPP. Overall, using SIF as a proxy for GPP and optimizing key parameters through data assimilation significantly enhanced the simulation accuracy of the VISIT model. However, challenges remain, such as model biases under cloudy conditions and SIF overestimation during specific stages. This research demonstrates the value of assimilating SIF data into the VISIT model and highlights the potential of satellite-derived SIF for improving GPP estimations, though at a small scale.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135763","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":"Macro- and Micro-Climate-Controlled Impacts of Heatwave With Drought on the Autumn Phenology of a Subtropical Forest Ecosystem","authors":"Wei Zhou,&nbsp;Zhenpeng Tian,&nbsp;Yao Zhang,&nbsp;Weimin Ju,&nbsp;Mou Leong Tan,&nbsp;Yun Yang,&nbsp;Fangfang Sun,&nbsp;Lu Dai,&nbsp;Jing Liu,&nbsp;Honggang Sun,&nbsp;Qin Ma","doi":"10.1029/2025JG008812","DOIUrl":"https://doi.org/10.1029/2025JG008812","url":null,"abstract":"<p>Heatwave and flash droughts are increasingly diminishing global vegetation productivity. Phenology, a key indicator of vegetation ecosystem responses to climate change, is crucial for regulating terrestrial carbon and water cycles. How heatwave with flash drought would influence phenology, particularly the autumn phenology, remains under-explored. Here we studied the heatwave with flash drought in summer 2022 over a subtropical forest ecosystem in China, and investigated its effects on autumn phenology from multiple aspects. We quantified land surface phenology using the MCD12Q2 derived End of Season (EOS) and compared the EOS in 2022 with that in normal years between 2000 and 2021. We found EOS was 8 days earlier than normal year, which indicated forests dropping leaf earlier to avoid excessive water loss and to increase survival rate. But their sensitivity to the event varied by macro-climatic conditions, terrain features, and forest attributes. Higher summer temperature advanced the EOS by approximately 1.49 days per 1°C (<i>R</i>² = 0.82). Microclimatic differences determined by terrain also impacted the EOS, with EOS advancing by 1 day for every 100 m decrease in elevation and 1 day for every 3.5° decrease in slope, respectively (<i>R</i>² = 0.94 and 0.95). Forests with different structural and composition features also responded differently to the extreme events. Coniferous forests were the least affected, while mature and taller forests showed greater resilience with less EOS advancement. These findings underscore the complex interactions between climatic events and ecosystem responses, highlighting the need for targeted conservation strategies and biodiversity protection.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144091672","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}