Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Novel Field Experiment on Alkalinity Enhancement in Intertidal Environments—A Trailblazer for Natural Climate Solutions","authors":"I. Mendes,&nbsp;J. Lübbers,&nbsp;J. Schönfeld,&nbsp;A. Baldermann,&nbsp;A. R. Carrasco,&nbsp;A. Cravo,&nbsp;A. Gomes,&nbsp;P. Grasse,&nbsp;F. M. Stamm","doi":"10.1029/2024JG008591","DOIUrl":"https://doi.org/10.1029/2024JG008591","url":null,"abstract":"<p>One recently proposed approach to reduce atmospheric CO₂ concentrations is marine alkalinity enhancement. This technique increases the CO₂ uptake capacity of seawater through weathering of fine-grained (mafic) rocks and minerals in marine environments. The weathering process has been extensively tested in laboratory studies and verified by numerical models. Field experiments scaling the CO₂ uptake under natural conditions are still lacking. In a methodological approach, a novel in situ experiment was designed and installed in a salt marsh at Ria Formosa coastal lagoon, southern Portugal. The experiment comprised deployments of different sizes of olivine and basalt substrates, and a control site, which were tidally submerged twice a day. A monthly monitoring scheme of supernatant and porewater properties from each deployment and control site was established, and procedures for temperature, salinity, oxygen, pH, total alkalinity, nutrient, and trace metal analyses were defined. This paper is devoted to the methods and describes the design, a protocol for the analyses, and an evaluation of experimental performance and reliability. Data from the first 6 months are presented for validation of the experiment. They demonstrated elevated total alkalinity in water samples, mostly in porewater after the deployments, while salinity, oxygen, and pH reflect the control conditions. Significant alkalinity differences were observed between the treatments and the natural background conditions monitored at the control site, during the 6 months of the experiment. The methodological approach is presented with strengths, limitations, and recommendations for an upscaling as CO₂ removal measure, servicing, and subsequent investigations.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008591","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513600","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":"Interplay of Seasonal Hydrology and Landscape Topography Drives Black Carbon Export in the Fraser River","authors":"Emily Brown,&nbsp;Sasha Wagner,&nbsp;Brian P. V. Hunt","doi":"10.1029/2024JG008627","DOIUrl":"https://doi.org/10.1029/2024JG008627","url":null,"abstract":"<p>Fire is an important driver of carbon cycling across terrestrial and aquatic ecosystems, but global fire regimes are changing. Black carbon (BC), a product of biomass burning, is more environmentally persistent than its parent biomass carbon and cycles differently than bulk organic carbon. This study aims to refine understanding of the environmental drivers of BC flux from land to ocean through year-long measurement of BC in the Fraser River in British Columbia, Canada. The Fraser River’s environmental context is distinct from systems that currently form the basis of understanding of BC export, characterized by highly seasonally variable hydrology, and with its basin spanning diverse ecosystems from glaciated mountainous regions to dry flatlands. We found that the Fraser River exported 18,765 ± 2,734 Mg yr⁻¹ of BC, with dissolved black carbon (DBC) comprising 3.3 ± 0.9% of annual dissolved organic carbon (DOC) flux, both lower than previous estimates would suggest. Strong seasonal variation in the DBC content of DOC and BC aromaticity were measured in the Fraser River. This reveals the importance of seasonal hydrology in the export of different pools of BC and indicates that seasonality and hydrologic regime should be given more consideration in future estimations of global riverine BC flux. These findings bring to light the importance of seasonality, hydrology, and basin topography in BC transport, with implications for global carbon cycles in a changing climate.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008627","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143497371","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":"SOMnmR: An R Package for Analyzing CP MAS 13C NMR Spectra of Environmental Samples","authors":"Luis Carlos Colocho Hurtarte,&nbsp;Noelia Garcia-Franco,&nbsp;Gabriela Villalba Ayala,&nbsp;Joerg Prietzel,&nbsp;Ingrid Koegel-Knabner","doi":"10.1029/2024JG008288","DOIUrl":"https://doi.org/10.1029/2024JG008288","url":null,"abstract":"<p>Cross-polarization (CP) magic angle spinning (MAS) ¹³C NMR spectroscopy is a versatile tool for studying organic matter (OM) in soils. Despite its versatility, the extensive post-processing required—including spinning-sidebands (SSB) correction and integration—limits its broader use. We present a new open-source R package, “SOMnmR” (accessible on CRAN and GitHub), designed to quickly process a large number of spectra, correcting for SSBs if required. The package computes the relative abundance of functional groups and can also model organic matter composition using end-member compounds. We describe the package's installation and functionalities and provide examples that (a) compare the results of two different spectrometers and (b) model the results of a large CP MAS ¹³C NMR data set. Overall, the presented package is a valuable tool for the fast analysis of ¹³C NMR data sets.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143475545","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":"Peatland Plant Community Changes in Annual Production and Composition Through 8 Years of Warming Manipulations Under Ambient and Elevated CO2 Atmospheres","authors":"P. J. Hanson,&nbsp;N. A. Griffiths,&nbsp;V. G. Salmon,&nbsp;J. M. Birkebak,&nbsp;J. M. Warren,&nbsp;J. R. Phillips,&nbsp;M. P. Guilliams,&nbsp;K. C. Oleheiser,&nbsp;M. W. Jones,&nbsp;N. J. Jones,&nbsp;J. Enterkine,&nbsp;N. F. Glenn,&nbsp;K. J. Pearson","doi":"10.1029/2024JG008511","DOIUrl":"https://doi.org/10.1029/2024JG008511","url":null,"abstract":"<p>The Spruce and Peatland Responses Under Changing Environments (SPRUCE) experiment has operated five whole-ecosystem warming manipulations (+0, +2.25, +4.5, +6.75, and +9°C) with paired ambient and elevated CO₂ atmospheres (eCO₂, +500 ppm) for 8 full calendar years (since August 2015). We tracked shrub-layer vegetation responses to the treatments using annual destructive plot sampling. Tree (<i>Picea</i> and <i>Larix</i>) responses were assessed annually using nondestructive dimensional analyses and allometric conversions. Shrub community changes were assessed for key ericaceous shrubs (<i>Rhododendron, Chamaedaphne,</i> and <i>Kalmia</i>), two <i>Vaccinium</i> species (<i>V. angustifolium, V. oxycoccos</i>), graminoid species (mostly <i>Eriophorum</i>), and one common forb (<i>Maianthemum trifolium</i>), plus minor understory species. We tracked annual aboveground net primary production (ANPP) for vascular plant species in gC m⁻² y⁻¹ and overall stand contribution in dry mass. We observed a linear increase in shrub-layer aboveground biomass accumulation with warming over time due primarily to an increase in ericaceous shrub abundance. Cumulative biomass increases across the shrub community showed overall positive responses to eCO₂ after 8 years. Community composition also changed with warming, with increases in woody shrub density, and the reduction or loss of forbs. The tree community showed minimal initial responses to warming early in the treatments, but since 2020, has shown significant increases in ANPP and individual tree growth with warming. The main driver of change in the vascular plant community was temperature, with less pronounced effects of eCO₂ evident. These results indicate an overall increase in ANPP with warming from both the tree and shrub layers of peatland vegetation.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008511","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446957","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":"Monitoring Peatland Condition and Restoration Sites Using Vertical Surface Motion Data From the European Ground Motion Service","authors":"M. P. Wilson","doi":"10.1029/2024JG008670","DOIUrl":"https://doi.org/10.1029/2024JG008670","url":null,"abstract":"<p>Vertical displacement data from satellite interferometric synthetic aperture radar (InSAR) can indicate peatland condition and can therefore be used for restoration site identification or monitoring programs. However, many peatland scientists and restoration practitioners lack InSAR expertise and do not have the financial resources available to purchase data processed by commercial third parties. Conversely, the European Ground Motion Service (EGMS) freely provides pre-processed vertical displacement data derived from the Sentinel-1 satellites. Using data covering the North Pennines National Landscape, England, this study is the first to investigate the potential for using EGMS Level 3 Ortho products to monitor landscape-scale peatland condition and the impacts of site-scale restoration. Linear regression analysis showed that, despite site restoration being considered successful based on visually extensive re-vegetation and water retention, the peatland is still subsiding at rates of −1.3 to −4.4 mm/year, likely because more time is needed for peat-forming <i>Sphagnum</i> spp. to re-colonize the site and exceed degradation rates. Nevertheless, there were indications that restoration interventions may be slowing subsidence in some areas and seasonally linked bog breathing may be returning to the site, which was absent prior to restoration efforts. The largest drawback of the EGMS Ortho products is their limited spatial coverage in rural vegetated locations, meaning peatlands are unlikely to receive the near-full coverage possible using advanced InSAR techniques. Nonetheless, where EGMS Ortho product coverage does exist, vertical displacement data can offer useful insight into the dynamic functionality of peatlands which cannot be obtained through monitoring programs based on visual observations.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438986","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":"Species-By-Species Pattern Analysis of Coastal Dune Vegetation","authors":"D. Demichele,&nbsp;E. Belcore,&nbsp;M. Piras,&nbsp;C. Camporeale","doi":"10.1029/2024JG008419","DOIUrl":"https://doi.org/10.1029/2024JG008419","url":null,"abstract":"<p>Vegetation is crucial for stabilizing and developing coastal dunes. Different plant species exhibit different spatial distributions which reflect their environmental role and adaptation strategy. This study aims to provide a fine-scale species-by-species analysis of vegetation spatial patterns on coastal dunes within the San Rossore–Migliarino–Massacciuccoli Regional Park (Tuscany, Italy). A comprehensive vegetation data set generated by an Object-Based Image Analysis (OBIA) algorithm applied to high-resolution ortho-images has been utilized. A Digital Terrain Model (DTM) of the study area was created to assess the impact of dune morphology on plant distribution. Moreover, a wave runup analysis was also conducted to understand the interaction between vegetation and hydrodynamic forces. The research highlights how the vegetation threshold distance from the coastline, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mi>veg</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${L}_{mathit{veg}}$</annotation>\u0000 </semantics></math>, is superimposed by the reaching distance of wave runup during extreme events. Terrain morphology significantly affects the vegetation zonation: on taller and undisturbed dunefields, species zonation is clearer and more defined, whereas, on flatter and disturbed ones, spatial distribution is significantly fuzzier. A positive correlation emerges between the abundance of a species and its degree of spatial clustering, indicating how less abundant species form more tightly clustered spatial patterns. Modified Ripley's L-function analysis revealed a multi-scale clustered pattern for most species under examination. The present results may provide a solid benchmark in coastal ecology research for supporting natural-based conservation plans and eco-morphodynamic modeling.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008419","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143431173","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":"N2O Emission From a Subtropical Forest Is Dominantly Regulated by Soil Denitrifiers Under Exogenous N Enrichment and Seasonal Precipitation Distribution Change","authors":"Xiaoge Han,&nbsp;Changchao Xu,&nbsp;Xiangping Tan,&nbsp;Yanxia Nie,&nbsp;Jinhong He,&nbsp;Qi Deng,&nbsp;Weijun Shen","doi":"10.1029/2024JG008206","DOIUrl":"https://doi.org/10.1029/2024JG008206","url":null,"abstract":"<p>Nitrogen-rich tropical/subtropical forest soil acts as a terrestrial source of nitrous oxide (N₂O), a greenhouse gas commonly affected by soil nitrogen availability and soil moisture. However, in tropical and subtropical regions experiencing both elevated nitrogen deposition and altered precipitation regimes, it is unclear whether nitrogen deposition and precipitation regimes have interactive effects on forest soil N₂O emissions and what roles N₂O-associated nitrifiers/denitrifiers play in these interactions. We conducted a 2 year field study in a subtropical evergreen broadleaf forest in southern China by applying four treatments: nitrogen addition (N), seasonal precipitation distribution change (PC), both nitrogen addition and seasonal precipitation distribution change (NPC) and a control (C). We found that N₂O efflux from the forest soil was significantly greater in the wet season than in the dry season, but was promoted by 77.4% by the NPC treatment only in the dry season. Soil moisture and pH decreased in the PC and N treatments, respectively. The abundance of nitrifying gene AOA-<i>amoA</i> and denitrifying gene <i>nosZ</i> in the wet season and the abundance of denitrifying gene <i>nirK</i> in the dry season differed significantly among the four treatments. A structural equation model showed that precipitation change was more important than nitrogen addition in affecting soil properties (e.g., moisture and pH) and N₂O-associated nitrifiers/denitrifiers, while soil <i>nirK</i>- and <i>nosZ</i>-denitrifiers were the dominant functional microbes in regulating N₂O emissions. The results support predictions of future nitrogen losses (N₂O) in subtropical forests in the context of interactions between elevated nitrogen deposition and altered precipitation regimes.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143404500","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":"Nitrogen Source Preferences and Ecological Implications of Phytoplankton Primary Production in the Yellow Sea, South Sea of Korea, and East/Japan Sea, 2018","authors":"Hyo Keun Jang,&nbsp;Jae Joong Kang,&nbsp;Dabin Lee,&nbsp;Kwanwoo Kim,&nbsp;Myung Joon Kim,&nbsp;Sanghoon Park,&nbsp;Yejin Kim,&nbsp;Jaesoon Kim,&nbsp;Huitae Joo,&nbsp;Seok-Hyun Youn,&nbsp;Sang Heon Lee","doi":"10.1029/2024JG008061","DOIUrl":"https://doi.org/10.1029/2024JG008061","url":null,"abstract":"<p>Understanding the partitioning of primary production into new and regenerated productions, based on nitrate or ammonium utilization, is crucial to understanding biogeochemical processes and marine ecosystems. This study addresses the scarcity of information on new and regenerated productions in the Yellow Sea (YS), South Sea (SS), and East/Japan Sea (EJS). Employing the ¹³C–¹⁵N tracer method, we quantified carbon and nitrogen uptake rates of phytoplankton across four seasons in 2018. Seasonal nitrate and ammonium uptake rates exhibited distinct ranges in the YS (0.2–6.1 and 0.4–22.3 mg N m⁻² hr⁻¹), SS (1.0–15.6 and 4.5–15.4 mg N m⁻² hr⁻¹), and EJS (1.5–7.3 and 4.5–15.4 mg N m⁻² hr⁻¹). Notably, nitrate uptake rates in the YS (except spring), SS, and EJS were generally lower than ammonium uptake rates, attributed to the dominance of pico-sized (&lt;2 μm) phytoplankton with a high affinity for ammonium. Carbon uptake rates in all seas displayed significant positive correlations with nitrate uptakes rather than ammonium uptakes, suggesting that the prevailing ammonium assimilations by dominant pico-sized phytoplankton contributed to the lower primary productions in 2018. Estimated annual new productions (30, 24, and 43 g C m⁻² y⁻¹) in the YS, SS, and EJS fall within the reported ranges for other regions. However, the EJS exhibited lower productions than previous reports (146 g C m⁻² y⁻¹), potentially impacting fishery yields and export production to the deep ocean in 2018. These findings, in the context of rapid environmental changes, provide crucial baseline information for monitoring future marine ecosystems in Korean seas.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143404499","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":"Extensive Oxygen Consumption in the Intertidal Infiltration Zone of Beach Aquifers—The Impact of Seasonal Input, Filtration Efficiency, and Morphodynamics","authors":"F. Auer,&nbsp;S. Ahmerkamp,&nbsp;J. Cueto,&nbsp;C. Winter,&nbsp;M. Holtappels","doi":"10.1029/2024JG008291","DOIUrl":"https://doi.org/10.1029/2024JG008291","url":null,"abstract":"<p>Seawater infiltration into the permeable sands of beach aquifers creates a high input of biogeochemical reactants driven by tides and waves. The upper sand layer acts as a filter, retaining particulate organic matter (POM), which is degraded by bacteria under predominantly oxic conditions. The seasonal variation of seawater POM and oxygen (O₂) entering the infiltration zone, combined with the POM filtration efficiency of the highly morphodynamic upper layer, determines the organic matter turnover and subsequent redox gradients along porewater flowpaths. We investigated these effects by quantifying the seasonal O₂ consumption rates directly from the incubations of sediments taken along a transect in the seawater infiltration zone at Spiekeroog Beach, Germany. We carried out a two-monthly year-long sampling campaign with high spatial resolution measurements down to 1 m depth. In summer, O₂ consumption rates of up to 106 μM hr⁻¹ were found in the first decimeters with a significant decline over depth, indicating efficient retention of reactive POM in the surface layer. Seasonal variation in organic carbon of the sand's suspendable particulates indicates rapid turnover and little storage. In winter, rates decreased significantly to below 11 μM hr⁻¹. Integrated over the investigated oxic layer, the estimated carbon mineralization varies between 15 (winter) and 143 (summer) mmol C m⁻² d⁻¹ with a yearly average of 73 mmol C m⁻² d⁻¹. The yearly CO₂ production of 35 kg per meter shoreline characterizes the beach as a high-throughout system with rapid OM remineralization in the retention layer, especially in summer, but with little OM storage.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008291","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396905","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":"PDO Dynamics Shape the Fire Regime of Boreal Subarctic Landscapes in the Northwest Territories, Canada","authors":"Nina Ryzhkova,&nbsp;Hugo Asselin,&nbsp;Adam A. Ali,&nbsp;Alexander Kryshen,&nbsp;Yves Bergeron,&nbsp;Daniela Robles,&nbsp;Sara Pineda-Zapata,&nbsp;Igor Drobyshev","doi":"10.1029/2024JG008178","DOIUrl":"https://doi.org/10.1029/2024JG008178","url":null,"abstract":"<p>Spatially explicit reconstructions of fire activity in northwestern boreal Canada are rare, despite their importance for modeling current and future disturbance regimes and forest dynamics. We provide a dendrochronological reconstruction of historical fire activity along Highway 3 in the Northwest Territories (NWT), Canada, within the boreal subarctic zone. We dated 129 fires that occurred between 1202 and 2015 CE, using samples from 479 fire-scarred living and dead jack pine trees (<i>Pinus banksiana</i> Lamb.). Three distinct periods can be distinguished in terms of historical fire cycle (FC) and fire occurrence. Initially (1340–1440 CE), fire activity was low (FC = 572 years; 1 fire/decade), before increasing notably between 1460 and 1840 (FC = 171 years; 4.45 fires/decade), and even more in recent times (1860–2015 CE; FC = 95 years; 7.63 fires/decade). Climate has been an important factor controlling changes in fire frequency and FC in the NWT since the 1300s. The 1440s and 1850s correspond with periods of increased fire activity synchronized with shifts from negative to positive Pacific Decadal Oscillation (PDO) phases. Since the mid-1800s, human activities may have contributed to the increase in fire activity, but climate remained the leading factor. During the 20th century, years with increased area burned corresponded to periods with drier-than-average conditions associated with positive PDO, suggesting fire activity in the study region is still influenced by climate. Spatial teleconnection patterns among PDO, drought, and large fire years (LFYs) in the NWT reveal persistent relationships between ocean-atmosphere circulation patterns and fire activity. PDO dynamics hold strong potential for predicting regional fire hazards across northwestern North America.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008178","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396904","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}