Journal of Geophysical Research: Biogeosciences最新文献

{"title":"On the Assessment of Sinking Particle Fluxes From In Situ Particle Size Distributions","authors":"Elena Ceballos Romero,&nbsp;Ken Buesseler,&nbsp;Erik Fields,&nbsp;Rainer Kiko,&nbsp;Meg Estapa,&nbsp;Lee Karp-Boss,&nbsp;Samantha Clevenger,&nbsp;Laetitia Drago,&nbsp;David A. Siegel","doi":"10.1029/2025JG008861","DOIUrl":"https://doi.org/10.1029/2025JG008861","url":null,"abstract":"<p>The biological carbon pump is a vital component of the global carbon cycle, particularly through the sinking of particulate organic carbon (POC) into the ocean interior. Particle size distribution (PSD) observations from the Underwater Vision Profiler (UVP) have been widely used to quantify sinking POC fluxes. This approach assumes that the sinking POC flux is a function of the PSD multiplied by a power law relating particle size to sinking rates and carbon content. The coefficients of the power law are quantified by regressing UVP data against sediment trap flux observations. Here, we systematically assess the performance of this approach using a large UVP data set of co-located and coincident sediment trap and thorium-234 flux observations from the North Pacific (50°N, 145°W, August 2018) and the North Atlantic (49°N, 16.5°W, May 2021) sampled during the EXPORTS (EXport Processes in the Ocean from RemoTe Sensing) field campaign, which span both diverse environmental conditions and sinking flux values. Globally, when power law coefficients are evaluated over all sites and depths, the UVP flux method explains 80% of the variance in POC flux. However, when coefficients are determined using regional subsets of the EXPORTS data set, the method performs poorly. Reasons include lack of knowledge of particle characteristics beyond PSD, undersampling of rare large particles, spatial and temporal scale mismatches between UVPs and flux observations, and difficulties arising from non-steady state conditions. To improve UVP-based sinking POC flux estimates regionally, additional data on particle characteristics such as transparency and morphology are needed.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008861","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147683404","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":"Implementing a Dynamic Root Distribution Scheme Responsive to Soil Environment Into Noah-MP-Crop: Improving Simulations of Soil Water, Crop Growth, and Energy Fluxes in Agro-Ecosystems","authors":"Huimin Meng,&nbsp;Chesheng Zhan,&nbsp;Shi Hu,&nbsp;Zhonghe Li,&nbsp;Zhonghui Lin","doi":"10.1029/2025JG009462","DOIUrl":"https://doi.org/10.1029/2025JG009462","url":null,"abstract":"<p>Reliable simulation of land–atmosphere interactions in land surface models (LSMs) requires realistic root distribution modeling, yet conventional static root parameterizations often fail to capture seasonal root dynamics in cropland ecosystems. In this study, we developed a soil–environment–responsive dynamic root distribution scheme (SE_root) within the Noah-MP-Crop framework that explicitly accounts for soil moisture (SM), temperature, aeration, bulk density, and soil texture. Evaluations against in situ observations in the North China Plain demonstrated that SE_root substantially outperformed the default static (fixed_root) and exponential dynamic (Exp_root) parameterizations. Site-scale simulations exhibited improved accuracy in capturing SM dynamics, leaf area index (LAI), and latent heat flux (LHF), yielding <i>R</i>² values consistently above 0.56. The simulated vertical root biomass distribution, with approximately 70% of root biomass concentrated in the upper 40 cm and declining with depth, closely matched field observations. Relative to the fixed_root and Exp_root schemes, the site-scale mean absolute errors were reduced by 10%–12% for SM and 4%–10% for LAI. Regional simulations further revealed that by capturing the dynamic feedback between root growth and local soil constraints, SE_root better represented the spatial heterogeneity of SM and LAI, alongside modest LHF improvements. Overall, incorporating this soil-responsive root parameterization improves the representation of SM dynamics, root allocation, crop growth, and land–atmosphere exchanges. These findings underscore the importance of explicitly representing root–soil interactions in agricultural LSMs, offering a robust pathway for coupling with climate models to capture crop–climate feedbacks and support sustainable management.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147683495","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 Coastal Vegetation Dynamics and Ecosystem Impacts Under Elevated CO2 and Temperature: A Process-Based Approach","authors":"Junyan Ding,&nbsp;Nate McDowell,&nbsp;Nathan Conroy,&nbsp;Donnie J. Day,&nbsp;Yilin Fang,&nbsp;Kenneth M. Kemner,&nbsp;Matthew L. Kirwan,&nbsp;Matthew Kovach,&nbsp;Patrick Megonigal,&nbsp;Kendalynn A. Morris,&nbsp;Teri O’Meara,&nbsp;Stephanie C. Pennington,&nbsp;Roberta B. Peixoto,&nbsp;Peter Thornton,&nbsp;Michael N. Weintraub,&nbsp;Peter Regier,&nbsp;Leticia Sandoval,&nbsp;Fausto Machado-Silva,&nbsp;Alice Stearns,&nbsp;Nicholas D. Ward,&nbsp;Stephanie J. Wilson,&nbsp;Vanessa Bailey","doi":"10.1029/2025JG009305","DOIUrl":"https://doi.org/10.1029/2025JG009305","url":null,"abstract":"<p>Coastal forests are increasingly vulnerable to climate change and sea-level rise, with flooding and salinity driving transitions to marsh-dominated ecosystems. Using the coastal version of FATES-Hydro, we conducted 30-year simulations at two coastal forest sites—a broadleaf swamp white oak stand at Lake Erie and a conifer loblolly pine stand at Chesapeake Bay—under historical climate and elevated CO₂ (+100 ppm) and temperature (+1.5°C) scenarios. Elevated CO₂ increased net primary productivity at both sites, while warming alone intensified hydraulic stress and accelerated mortality, particularly in the conifer stand. Simulations show that elevated temperatures intensify vapor pressure deficit and hydraulic stress on trees already experiencing salinity- and submersion-driven water stress, increasing tree mortality beyond what would be expected in a non-water-limited environment. Marsh expansion partially compensated for tree loss at the Lake Erie site but reduced ecosystem productivity in the conifer forest at Chesapeake Bay. Our results highlight how differences in stand structure, phenology, and local hydrology modulate ecosystem trajectories under climate change, emphasizing the importance of demographic and community-level processes for predicting the fate of coastal forests.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147683389","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":"Improved Joint Estimation of Daily Actual Evapotranspiration and Gross Primary Production by Integrating Landsat, Sentinel-2, Sentinel-1, and Climate Data With Machine Learning","authors":"Jiang Chen,&nbsp;Paul C. Stoy,&nbsp;Zhou Zhang","doi":"10.1029/2025JG009246","DOIUrl":"https://doi.org/10.1029/2025JG009246","url":null,"abstract":"<p>Accurate fine spatial resolution evapotranspiration (ET) and gross primary production (GPP) estimates will help us understand water-carbon interactions and optimize water resource management for enhancing ecological and agricultural applications. However, previous studies usually estimated ET or GPP separately at relatively coarse spatial or temporal resolution that is often insufficient for agricultural management. Besides, although Landsat provides fine-scale data, a single Landsat optical satellite can obtain limited observations. To address these issues, this study attempts to jointly estimate daily actual ET and GPP at 30-m resolution by integrating Landsat, Sentinel-2, Sentinel-1, and climate data with machine learning. Multisource optical and radar data were first integrated into unified Sentinel-2 vegetation indices (VIs) using linear and random forest (RF) models. Improved daily VIs were generated using climate data and temporally adjacent multisource satellite VIs with a bidirectional iteration approach. Finally, daily actual ET and GPP were jointly estimated using improved daily VIs and climate data. The results showed that the bidirectional iteration model improved daily VIs (<i>R</i>² &gt; 0.882; RMSE &lt; 0.077). Using the improved daily VIs, the total number of daily actual ET and GPP estimates were greatly improved (<i>N</i> = 23,669 vs. 3,657 and 8,771) compared to Sentinel-2 and integrated multisource satellite VIs. The RF model performed better than the other five evaluated machine learning algorithms for estimating ET (<i>R</i>² = 0.815; RMSE = 0.716 mm/d) and GPP (<i>R</i>² = 0.753; RMSE = 2.011 gC/m²/d). The study proposed a feasible methodological framework to jointly estimate daily actual ET and GPP at 30-m resolution, presenting great potential to monitor small-scale water stress and plant growth.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009246","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147683147","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":"Atmospheric Ammonia Deposition: A Significant Source of Nitrogen to an Oligotrophic Lake and Its Watershed","authors":"D. P. Swaney,&nbsp;T. J. Butler,&nbsp;R. W. Howarth,&nbsp;R. Marino,&nbsp;G. M. Beachley,&nbsp;C. B. Baublitz","doi":"10.1029/2025JG009389","DOIUrl":"https://doi.org/10.1029/2025JG009389","url":null,"abstract":"<p>The increasing frequency of toxic cyanobacterial blooms (TCBs) in freshwater lakes in recent years has been problematic, both in terms of our understanding of basic drivers, and attempts to manage them. While phosphorus has been determined to limit the growth of blooms, some cyanophytes manufacture toxins with a high nitrogen (N) demand, so toxin production may be N-limited. Skaneateles Lake, an oligotrophic lake in New York, has experienced TCBs in recent years, despite its status as one of the cleanest lakes in the United States, and strict watershed regulations regarding agricultural and other nutrient sources. This study investigated whether gaseous ammonia (NH₃) deposition contributes to the nitrogen (N) load in the lake, potentially exacerbating the toxicity of these blooms. Using a network of NH₃ air samplers, we estimated both direct and indirect NH₃ deposition to the lake, and compared these fluxes to other sources of N to the lake and its watershed. Follow up sampling campaigns were conducted to extend the deposition estimates to Skaneateles into a second and third year, and to compare estimates of NH₃ deposition to nearby Owasco Lake. Our findings indicate that, not including potential contributions from reduced N deposition to the watershed, dry gaseous NH₃ deposition directly to Skaneateles Lake alone represents 11%–12% of the watershed N load to the lake with ammonium (NH₄⁺) deposition contributing another 7%–10% suggesting that strategies to manage atmospheric reduced N emissions from nearby agricultural sources could reduce the N loading to Skaneateles.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009389","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147683136","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":"Divergent Subtropical Forest Functional and Structural Responses to the 2022 Yangtze River Extreme Drought","authors":"Baoni Li,&nbsp;Junguo Liu,&nbsp;Dashan Wang,&nbsp;Xiaoye Liu,&nbsp;Shijing Liang,&nbsp;Shuyu Zhang,&nbsp;Guoqing Gong,&nbsp;Ling Zeng,&nbsp;Zhilin Guo,&nbsp;Jianhuai Ye,&nbsp;Chen Wang,&nbsp;Zhenzhong Zeng","doi":"10.1029/2025JG009291","DOIUrl":"https://doi.org/10.1029/2025JG009291","url":null,"abstract":"<p>As global warming intensifies, humid ecosystems are increasingly exposed to unexpected extreme droughts. However, it remains unclear how ecosystem functions, such as greenness and photosynthesis, and structures, such as leaf area, respond to such events and whether they decouple. We investigated the record-breaking 2022 growing-season drought in the humid Yangtze River Basin, where precipitation dropped ∼50% below average. Here we analyzed anomalies of remote sensing normalized difference vegetation index (NDVI) and solar-induced fluorescence (SIF) to indicate ecosystem functional responses, and leaf area index (LAI) to represent ecosystem structural responses. We applied machine learning models and SHapley Additive exPlanations (SHAP) analysis to attribute these responses to hydroclimatic anomalies and further examine topographic effects. Results indicate a striking divergence of ecosystem functional and structural responses, with NDVI decreasing by 8.4% and SIF declining by 2.2%, while LAI increasing by 1.8% relative to history (2001–2022). Notably, subtropical forest LAI surged by 9.8%, despite a marked decline in NDVI and SIF. Leaf growth was enhanced especially at higher elevations with dense canopies and abundant antecedent soil moisture. Energy conditions, that is, air temperature, vapor pressure deficit, and solar radiation, were found to strongly regulate ecosystem responses to drought. These results imply that humid ecosystems can sustain structural growth despite functional impairment under drought, likely through complex physiological regulation and complementary resource utilization. Our findings underscore the importance of incorporating the function-structure decoupling under extreme drought in photosynthesis and terrestrial carbon cycle estimations.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147683028","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":"Drivers of Dissolved Organic Matter Quality and Concentration in a Mountainous Subarctic Watershed, Yukon, Canada","authors":"Aliana C. Fristensky,&nbsp;Sean K. Carey","doi":"10.1029/2025JG009320","DOIUrl":"https://doi.org/10.1029/2025JG009320","url":null,"abstract":"<p>Northern permafrost regions contain vast frozen stores of organic carbon that are vulnerable to thaw and mobilization. While considerable attention has been paid to carbon export from large Arctic rivers, gaps remain in characterizing dissolved organic matter (DOM) quality and export in permafrost influenced catchments that contain a mosaic of landscape types. This study examines the spatial and temporal factors influencing DOM quality, concentration and export over a 4-year period across the Wolf Creek Research Basin, Yukon, Canada. Optical indices were used to assess changes in DOM quality across six sites that ranged from permafrost dominated headwaters to forested lowlands and included wetlands and a lake. Results indicate that DOM export was transport-limited with greater exports in years with record high snowpacks and flows. Seasonality was responsible for the greatest variability in DOM quality, yet landscape type was an important factor during the open water season. High SUVA₂₅₄/HIX in headwater streams indicated primarily humic, terrestrially derived DOM, whereas high BIX and comparatively lower SUVA₂₅₄/HIX in a mid-catchment lake indicated autotrophic production of new DOM. DOM quality at the catchment outlet reflected a mixture of upstream sources and increased influence of groundwater. During high snow and streamflow years, DOM was humic and aromatic compared with low flow years, which had a greater portion of the recent microbial and autochthonous production. Results highlight the importance of evaluating DOM quality across all seasons and among years, and the relative influence of different landscape types and responses to rapid environmental change in cold environments.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009320","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147667950","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":"Salt Marsh Blueprints: Using Carbon Isotopes to Understand Soil Organic Matter Legacies","authors":"Madeleine Meadows-McDonnell,&nbsp;Michael T. Hren,&nbsp;Zhao Wang,&nbsp;Beth A. Lawrence","doi":"10.1029/2025JG009325","DOIUrl":"https://doi.org/10.1029/2025JG009325","url":null,"abstract":"<p>Salt marshes are important blue carbon sinks and dynamic, connective ecosystems that experience change across a wide range of temporal scales, from daily tidal inundation to decadal and century-scale human modifications to sea level rise over millennia. However, whether short-term (∼100-year) ecosystem shifts can be detected in soil carbon records remains unclear. Here, we use carbon isotopes (<i>δ</i>¹³C) to reconstruct the recent vegetation and land-use changes in a well-studied salt marsh in Connecticut, USA. Leveraging the distinct isotopic signatures of dominant species (C₃ <i>Phragmites australis</i> and C₄ <i>Spartina alterniflora</i>), we analyzed bulk <i>δ</i>¹³C, <i>n</i>-alkane <i>δ</i>¹³C, and soil CO₂, CH₄ <i>δ</i>¹³C to (a) reconstruct plant community shifts associated with historical farming, ditching, tidal restrictions, and subsequent restoration, (b) evaluate the sensitivity of bulk versus leaf wax <i>δ</i>¹³C to ecological change, and (c) compare soil carbon legacies with soil CO₂ and CH₄ emissions. Both bulk sediment and leaf wax <i>δ</i>¹³C records capture the imprint of historical ditching and draining practices but do not clearly record vegetation changes associated with tidal restrictions and restoration over the past 60 years. <i>n</i>-Alkane sediment <i>δ</i>¹³C preserves evidence of C₄ vegetation from 90 years ago that are not resolved in bulk sediment <i>δ</i>¹³C values. Soil CO₂ <i>δ</i>¹³C reflects modern vegetation inputs combined with isotopic enrichment associated with microbial processing. These results demonstrate that carbon isotopes can effectively reconstruct ecosystem history where C₃ and C₄ vegetation are distinct, and leaf wax <i>δ</i>¹³C provides a more sensitive archive of plant-derived inputs to marsh soil organic matter than bulk <i>δ</i>¹³C.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682889","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":"Modeling Upper Ocean Ecosystem Dynamics in Response to Interannual Sea-Ice Variability in the Western Antarctic Peninsula","authors":"Catherine R. Czajka,&nbsp;Jessica S. Turner,&nbsp;Sharon Stammerjohn,&nbsp;Heather H. Kim,&nbsp;Oscar Schofield,&nbsp;Benjamin T. Saenz,&nbsp;Scott C. Doney","doi":"10.1029/2025JG009428","DOIUrl":"https://doi.org/10.1029/2025JG009428","url":null,"abstract":"<p>In the Western Antarctic Peninsula (WAP), marine plankton dynamics are tightly linked to the interannual variability in environmental conditions, including phenological shifts in sea-ice seasonality. To explore these linkages, we use a 1-dimensional vertical ocean-ice-ecosystem model (KPP-Eco-Ice, or KEI) that simulates physical and ecosystem conditions at a continental shelf mooring location in the Palmer Long Term Ecological Research program sampling grid. KEI allows for year-round examination of the ecosystem in a region where in situ observations on the shelf are limited to January. Comparisons are made between seasonal sea-ice retreat, mixed layer depth, primary productivity, and phytoplankton relative abundance, grazing, and loss rates. KEI successfully captures seasonal patterns in the WAP, demonstrating that total seasonal primary production was highest following a winter with late sea-ice retreat. Stability in the surface mixed layer enables high photosynthetic rates by alleviating light limitation, while wind-induced surface mixing results in lower phytoplankton production and biomass in years with early sea-ice retreat. However, mixing reduces iron limitation in surface waters, which may influence phytoplankton species composition. Small, non-diatom phytoplankton are better-adapted to high light and low iron conditions, thriving longer in a year with late sea-ice retreat and higher seasonal primary production, while larger diatoms are more abundant in the years with early sea-ice retreat and lower seasonal production. These findings have implications for grazer populations and subsequent carbon export from the surface to depth in the WAP region. This study validates the role that sea ice plays in shaping Antarctic ecosystem dynamics.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009428","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682887","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":"Storm-Scale Temporal Dynamics of Throughfall Dissolved Organic Matter Revealed by High-Resolution Mass Spectrometry","authors":"Hollis C. Harrington,&nbsp;John P. Hassett,&nbsp;Leanne C. Powers","doi":"10.1029/2025JG009457","DOIUrl":"https://doi.org/10.1029/2025JG009457","url":null,"abstract":"<p>Forest canopies intercept a substantial portion of rainfall, altering not only hydrologic pathways but also the chemical composition of water reaching the forest floor. Throughfall dissolved organic matter (DOM) represents an important input of carbon and nutrients; however, little is known about how its molecular composition changes during individual storm events. Here, we present the first application of high-resolution mass spectrometry (HRMS) to characterize intrastorm dynamics of throughfall DOM. Fifteen sequential samples collected during a precipitation event in a mixed conifer forest showed clear first flush dynamics for dissolved organic carbon, which declined from 20.6 to 5.3 mg-C L⁻¹. Molecular diversity, measured as the number of HRMS features, also decreased from 934 to 439, indicating a decline in compositional complexity after the onset of precipitation. Biosynthetic pathways displayed a strong inverse relationship, with amino acid/peptide intensities decreasing as terpenoid intensities increased (<i>R</i>² = 0.96). In contrast, optical indices and HRMS data diverged in several cases, including temporal patterns in aromaticity, underscoring that widely used optical indices may not be universally applicable outside the systems in which they were developed. Together, these findings demonstrate that the molecular composition of throughfall DOM is highly dynamic within storm events, with pathway-specific responses to rainfall. Such variability suggests that projected changes in storm frequency and intensity under future climate scenarios may substantially alter the composition and ecological role of canopy-derived organic matter. These findings also highlight the need to carefully evaluate methodological choices, including solid-phase extraction approaches that may bias DOM recovery.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682952","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}