Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Evaluating Hysteresis Patterns in Sap Flow of a Red Pine Forest Subjected to Different Variable Retention Harvesting Treatments","authors":"Elizabeth Arango Ruda,&nbsp;M. Altaf Arain","doi":"10.1029/2024JG008363","DOIUrl":"https://doi.org/10.1029/2024JG008363","url":null,"abstract":"<p>Forests significantly influence regional and global water cycles through transpiration, which is affected by meteorological variables, soil water availability, and stand and site characteristics. Variable retention harvesting (VRH) is a forest management practice in which varying densities of trees, such as 55% and 33%, are retained after thinning or harvesting. These trees can be grouped together or evenly distributed. VRH aims to enhance forest growth, improve biodiversity, preserve ecosystem functions, and generate economic revenue from harvested timber. Application of VRH treatment in forest ecosystems can potentially impact the response of forest transpiration to environmental controls. This study analyzed the impacts of four different VRH treatments on sap flow velocity (SV) in an 83-year-old red pine (<i>Pinus resinosa Ait</i>.) plantation forest in the Great Lakes region in Canada. These VRH treatments included 55% aggregated (55A), 55% dispersed (55D), 33% aggregated (33A), and 33% dispersed (33D) basal area retention, and an unharvested control (CN) plot, 1 ha each. Analysis of counterclockwise hysteresis loops between SV and meteorological variables showed larger hysteresis areas between SV and photosynthetically active radiation (PAR) than vapor pressure deficit (VPD) and air temperature (<i>T</i>_air), particularly in clear sky and warm temperatures in the summer. It demonstrated that PAR was the primary control on SV across VRH treatments, followed by VPD and <i>T</i>_air. Larger hysteresis loop areas and higher SV values were observed in the CN and 55D treatments, with lower values found in the 55A, 33D, and 33A plots. This suggests that maintaining dispersed retention of 55% basal area (55D) is the optimal forest management practice that can be utilized to enhance transpiration and forest growth. These findings will assist forest managers and other stakeholders to adopt sustainable forest management practices, thereby enhancing forest growth, water use efficiency, and resilience to climate change. Additionally, these practices will contribute to nature-based climate solutions.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008363","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074432","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":"Multi-Year Nutrient and Organic Carbon Mass Balance of a Young Boreal Hydroelectric Reservoir Complex","authors":"Bianca M. Rodríguez-Cardona,&nbsp;Pascal Bodmer,&nbsp;François Bilodeau,&nbsp;Alain Tremblay,&nbsp;Paul A. del Giorgio","doi":"10.1029/2024JG008607","DOIUrl":"https://doi.org/10.1029/2024JG008607","url":null,"abstract":"<p>Reservoir construction can alter the transport and export of nutrients and organic matter by rivers to coastal areas. However, influences from construction within the first years after flooding are not well understood. Here we present a 9-year study of La Romaine Hydroelectric Complex, composed of four cascading boreal reservoirs sequentially commissioned along La Romaine River in Northeastern Québec, Canada. We followed longitudinal and temporal patterns in concentrations of total nitrogen (TN), total phosphorus (TP), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and particulate organic matter (POM) in the river above, within each reservoir, and downriver into the estuary, during and after reservoir construction. TN concentrations varied greatly within and between successive reservoirs, suggesting that reservoir habitats can be sources and sinks of N, but concentrations below the Complex remained on average like those upriver. In contrast, TP consistently increased longitudinally and were greater below the reservoirs than upriver, suggesting that these young boreal reservoirs are net sources of phosphorous. DOC and DIC concentrations were relatively constant through the reservoir continuum, suggesting no net change despite evidence of variable but intense C processing seasonally and annually. POM was highly dynamic but consistently declined through the reservoirs. Although reservoirs were influenced by upstream conditions, each had their own distinct nutrient and carbon dynamics, likely influenced by morphometry, residence time, and pre-flood landscape. As reservoirs and the Complex age, they can individually or collectively shift from becoming less of an enhanced source of materials relative to pre-flooding, to sinks of transported material.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008607","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074433","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":"Riparian Zone Heterogeneity Influences the Amount and Fate of Biodegradable Dissolved Organic Carbon at the Land-Water Interface","authors":"Melissa Reidy,&nbsp;Martin Berggren,&nbsp;Anna Lupon,&nbsp;Hjalmar Laudon,&nbsp;Ryan A. Sponseller","doi":"10.1029/2024JG008471","DOIUrl":"https://doi.org/10.1029/2024JG008471","url":null,"abstract":"<p>The transport of biodegradable dissolved organic carbon (bDOC) across land-water boundaries is central to supporting the ecological and biogeochemical functioning of freshwater ecosystems. Yet, we know little about how the generation and supply of terrestrial bDOC to streams and lakes is regulated by the physical, biological, and hydrological properties of the riparian interface. Here, we assessed how terrestrial, groundwater, and aquatic bDOC differ along flowpaths connecting riparian soils to a headwater boreal stream. We further tested how bDOC generation and supply differs among interfaces with distinct hydrogeomorphologies, as reflected by differences in soil properties, groundwater dynamics, and hydrological connectivity to the stream. We found that bDOC quantity declined sharply from terrestrial sources, to groundwater, to aquatic systems, and that these differences were associated with changes in the optical and chemical properties of the dissolved organic matter pool. However, bDOC generation and potential transport in groundwater varied across site types and reflected local differences in soil organic matter storage, depth to groundwater, and soil microbial community activity. Interface zones with organic-rich soils but weak hydrological connections had a large capacity to produce bDOC, but likely only laterally contributed organic resources during floods. By contrast, sites with stronger lateral hydrological connectivity served as persistent conduits for organic resources generated further upslope, even if the capacity to generate bDOC locally was weak. Overall, our results illustrate how hydrogeomorphic heterogeneity at the land-water interface can add spatial and temporal complexity to the generation and transfer of bDOC from soils to the inland water continuum.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008471","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944608","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":"Optimizing the Temperature Sensitivity of the Isoprene Emission Model MEGAN in Different Ecosystems Using a Metropolis-Hastings Markov Chain Monte Carlo Method","authors":"C. A. DiMaria,&nbsp;D. B. A. Jones,&nbsp;V. Ferracci,&nbsp;A. A. Bloom,&nbsp;H. M. Worden,&nbsp;R. Seco,&nbsp;L. Vettikkat,&nbsp;A. M. Yáñez-Serrano,&nbsp;A. B. Guenther,&nbsp;A. Araujo,&nbsp;A. H. Goldstein,&nbsp;B. Langford,&nbsp;J. Cash,&nbsp;N. R. P. Harris,&nbsp;L. Brown,&nbsp;R. Rinnan,&nbsp;S. Schobesberger,&nbsp;T. Holst,&nbsp;J. E. Mak","doi":"10.1029/2025JG008806","DOIUrl":"https://doi.org/10.1029/2025JG008806","url":null,"abstract":"<p>Isoprene is a reactive hydrocarbon emitted to the atmosphere in large quantities by terrestrial vegetation. Annual total isoprene emissions exceed 300 Tg a⁻¹, but emission rates vary widely among plant species and are sensitive to meteorological and environmental conditions including temperature, sunlight, and soil moisture. Due to its high reactivity, isoprene has a large impact on air quality and climate pollutants such as ozone and aerosols. It is also an important sink for the hydroxyl radical which impacts the lifetime of the important greenhouse gas methane along with many other trace gas species. Modeling the impacts of isoprene emissions on atmospheric chemistry and climate requires accurate isoprene emission estimates. These can be obtained using the empirical Model of Emissions of Gases and Aerosols from Nature (MEGAN), but the parameterization of this model is uncertain due in part to limited field observations. In this study, we use ground-based measurements of isoprene concentrations and fluxes from 11 field sites to assess the variability of the isoprene emission temperature response across ecosystems. We then use these observations in a Metropolis-Hastings Markov Chain Monte Carlo (MHMCMC) data assimilation framework to optimize the MEGAN temperature response function. We find that the performance of MEGAN can be significantly improved at several high-latitude field sites by increasing the modeled sensitivity of isoprene emissions to past temperatures. At some sites, the optimized model was nearly four times more sensitive to temperature than the unoptimized model. This has implications for air quality modeling in a warming climate.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008806","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944772","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":"Drivers on Carbon Accumulation Vary Along the Hydrological Gradient of a Subarctic Patterned Peatland","authors":"Hui Zhang,&nbsp;Sanna Piilo,&nbsp;Marco A. Aquino-López,&nbsp;Zhengtang Guo,&nbsp;Yan Zhao,&nbsp;Anna M. Laine,&nbsp;Aino Korrensalo,&nbsp;Eeva-Stiina Tuittila,&nbsp;Minna Väliranta","doi":"10.1029/2024JG008677","DOIUrl":"https://doi.org/10.1029/2024JG008677","url":null,"abstract":"<p>Peatlands are important climate change mitigation agents as they store large amounts of carbon (C). Yet, their C sink capacity is vulnerable to environmental changes, which is however uncertain in a changing climate. Here, we examined potential habitat-specific C accumulation drivers over the past ∼1,000 years, using replicate peat records sampled from dry strings and wetter lawns of a subarctic patterned peatland. We found that at both habitats water-table depth impacted the plant functional types and/or peat properties, but they impacted the C accumulation significantly only at lawns. Specifically, the plant functional type and water-table depth had stronger controls on C accumulation than peat properties. Our data suggest that drying-induced C accumulation decrease maybe compensated by <i>Sphagnum</i> expansion in wetter areas. This implies that peatland C accumulation at different habitats is likely to respond to climate changes in varying ways. Thus, quantification of the climatic links to habitat-specific succession and C processes is needed before peatland C sink capacity can be predicted.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008677","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143939148","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":"CO2 Emissions From Low Order Tundra Streams Stimulated by Surface-Subsurface Connectivity Following Extreme Rainfall Events","authors":"Alina C. Spera,&nbsp;Vanessa L. Lougheed","doi":"10.1029/2024JG008459","DOIUrl":"https://doi.org/10.1029/2024JG008459","url":null,"abstract":"<p>Increases to summer Arctic rainfall and tundra thermal degradation are altering hydrological cycling in coastal watersheds with implications for carbon (C) cycling and transport of C to the atmosphere and coast. Arctic riverine research has focused on large rivers; however, small streams contribute significantly to vertical and longitudinal carbon dioxide (CO₂) fluxes. Despite the well-established connection between hydrology and biogeochemistry, the impact of extreme rainfall events on Arctic aquatic C cycling remains a knowledge gap. This study characterized how hydrology, biogeochemistry, and geomorphology control the supply of CO₂ to low order streams and their propensity to act as atmospheric CO₂ sources. We characterize biogeochemical and hydrologic processes in unique reaches from a beaded stream and stream impacted by thermal erosion. Rainfall and its resulting increases to terrestrial-aquatic connectivity drove the movement of CO₂ and biodegradable dissolved organic C (BDOC) from soils into streams, however, BDOC mineralization only contributed a small portion of surface CO₂ fluxes. Rain events likely stimulated stream benthic respiration, which led to CO₂ contributions from net ecosystem production often exceeding surface CO₂ fluxes and downstream CO₂ transport. In addition, thermal degradation played a role in terrestrial-aquatic connectivity of the streams. The erosion-affected stream had inconsistent and smaller inputs of CO₂, had weaker heterotrophic conditions, and smaller CO₂ emissions. Understanding how hydrologic regime, influenced by late summer rain events and stream morphology, controls the transport of CO₂ and metabolism in small tundra streams will help improve predictions of landscape scale CO₂ emissions from these critically understudied systems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143939149","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":"Evidence of Mineral Alteration in a Salt Marsh Subterranean Estuary: Implications for Carbon and Trace Element Cycling","authors":"J. J. Tamborski,&nbsp;M. J. Eagle,&nbsp;M. T. Thorpe,&nbsp;M. A. Charette,&nbsp;B. L. Kurylyk,&nbsp;S. Rahman,&nbsp;K. D. Kroeger,&nbsp;J. O’Keefe Suttles,&nbsp;A. G. Mann,&nbsp;T. W. Brooks,&nbsp;Z. A. Wang","doi":"10.1029/2025JG008758","DOIUrl":"https://doi.org/10.1029/2025JG008758","url":null,"abstract":"<p>Subterranean estuaries (STE) in salt marshes are biogeochemically active zones where interactions between terrestrial groundwater and seawater drive complex cycling of carbon and trace elements, influenced by mineral dissolution. These systems, characterized by fine-grained organic-rich peat overlying permeable coastal aquifers, play a crucial role as a blue carbon sink, yet their geochemical dynamics remain poorly understood. We investigated dissolved trace elements, carbon, silica, and radium isotopes in a salt marsh STE (Sage Lot Pond, Waquoit Bay, MA) over seasonal and annual cycles. Our results reveal that groundwater and estuarine water circulation through marsh peat and aquifer sediments leads to enrichments of dissolved organic and inorganic carbon (DOC and DIC), Si, Ba, and Mn, with variable source/sink behavior of Fe and net removal of U. Submarine groundwater discharge dominated Ba fluxes, whereas pore water drainage from marsh peat acted as the main sink for U and source of Si. Fe cycling was variable, with terrestrial Fe largely removed as groundwater passed through the STE, consistent with Fe-sulfide and amorphous phase formation. Radium isotope ratios identified two distinct subsurface flow pathways, influenced by metal-oxide cycling and organic matter breakdown. Si production was decoupled from DIC, suggesting Si originates from mineral alteration, whereas DIC results from both mineral weathering and microbial respiration. Silicate mineral alteration, coupled with marsh pore water drainage, accounts for up to 16% of annual DIC exports (66 g C m⁻² y⁻¹), highlighting the importance of STEs in coastal carbon and trace element cycling, especially as marshes face environmental change.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008758","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143939521","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":"Meteorological and Vegetation Structure Controls on Liquid Throughfall in US Forests and Shrublands","authors":"Edward Ayres","doi":"10.1029/2024JG008519","DOIUrl":"https://doi.org/10.1029/2024JG008519","url":null,"abstract":"<p>Throughfall is the dominant input of water to most terrestrial ecosystems and is primarily driven by precipitation quantity, although the relationship varies among sites. A wide range of meteorological and site-based properties also influence throughfall and may explain this variability, but their importance for accurately predicting throughfall quantities across differing sites remains unknown. Here I develop models to predict daily throughfall quantities at ∼1 m² resolution based on up to 19 environmental parameters using multi-year data from sites throughout the US. Three random forest models of varying complexity were trained to predict throughfall: a simple model (RF-1) driven solely by precipitation quantity, and more complex models that incorporated an additional eight (RF-9) and eighteen (RF-19) variables. RF-1 was able to predict throughfall quantities (±28%) and accuracy was modestly improved by including additional model parameters (±24–26%). Improvements in model performance were most apparent for smaller precipitation events (&lt;10 mm), which are less likely to fully saturate the canopy (22% improvement in prediction accuracy for the RF-19 model). Precipitation quantity, maximum intensity, and duration were consistently identified as the most important drivers of throughfall, whereas variables relating to evaporative potential and canopy water storage capacity were identified as moderately important. These models allow the impacts of environmental changes (e.g., forest regrowth after clearcutting or increased precipitation intensity) to be evaluated, as well as inform decisions about which parameters to include in field- and model-based studies of throughfall and its converse, interception, when resources are limited.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008519","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143939147","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":"A Compact, Low-Cost Sensing System to Enable Distributed Measurements of Urban Tree Transpiration","authors":"Xiating Chen,&nbsp;Bobby Schulz,&nbsp;Indigo Davitt-Liu,&nbsp;Andrew D. Wickert,&nbsp;Xue Feng","doi":"10.1029/2024JG008653","DOIUrl":"https://doi.org/10.1029/2024JG008653","url":null,"abstract":"<p>Urban trees reduce air temperature and alleviate urban heat island effects through shading and transpiration, making them crucial components of climate adaptation strategies. Understanding their transpiration rates and patterns can give new insights into their response to climate stress, yet traditional sap-flux measurements—which often involve long extension cords and solar panels—are challenging to deploy in urban public areas. Here, we present a compact, low-cost monitoring system designed specifically for the urban deployment of the well-established Granier-style thermal dissipation sensors (TDS). Our design decentralizes heating control and data logging processes to individual trees through a custom printed circuit board (PCB) design that meets the technical requirements of TDS using affordable components. With reduced research footprint and equipment cost, the system is less vulnerable to the risk from and the consequence of vandalism in an urban setting. We validated this system through deployment on 18 ash trees (<i>Fraxinus</i> spp.) across four parks in the City of St. Paul, MN, USA in summer 2023, achieving a 72% data collection success rate. Our results demonstrate the system's capability for long-term urban ecohydrology monitoring while providing practical insights into deployment challenges and solutions. This technical advancement enables wider implementation of urban tree monitoring, supporting both basic research in urban tree physiology and applied management of urban forests under increasing environmental stress.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008653","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919560","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 Matter Composition Versus Microbial Source: Controls on Carbon Loss From Fen Wetland and Permafrost Soils","authors":"Sommer F. Starr,&nbsp;Kimberly P. Wickland,&nbsp;Anne M. Kellerman,&nbsp;Amy M. McKenna,&nbsp;Martin R. Kurek,&nbsp;Aubrey Miller,&nbsp;Ariana Katsaras,&nbsp;Thomas A. Douglas,&nbsp;Rachel Mackelprang,&nbsp;Ashley L. Shade,&nbsp;Robert G. M. Spencer","doi":"10.1029/2024JG008445","DOIUrl":"https://doi.org/10.1029/2024JG008445","url":null,"abstract":"<p>Wetland and permafrost soils contain some of Earth's largest reservoirs of organic carbon, and these stores are threatened by rapid warming across the Arctic. Nearly half of northern wetlands are affected by permafrost. As these ecosystems warm, the cycling of dissolved organic matter (DOM) and the opportunities for microbial degradation are changing. This is particularly evident as the relationship between wetland and permafrost DOM dynamics evolves, especially with the introduction of permafrost-derived DOM into wetland environments. Thus, understanding the interplay of DOM composition and microbial communities from wetlands and permafrost is critical to predicting the impact of released carbon on global carbon cycling. As little is understood about the interactions between wetland active layer and permafrost-derived sources as they intermingle, we conducted experimental bioincubations of mixtures of DOM and microbial communities from two fen wetland depths (shallow: 0–15 cm, and deep: 15–30 cm) and two ages of permafrost soil (Holocene and Pleistocene). We found that the source of microbial inoculum was not a significant driver of dissolved organic carbon (DOC) degradation across treatments; rather, DOM source and specifically, DOM molecular composition, controlled the rate of DOC loss over 100 days of bioincubations. DOC loss across all treatments was negatively correlated with modified aromaticity index, O/C, and the relative abundance of condensed aromatic and polyphenolic formula, and positively correlated with H/C and the relative abundance of aliphatic and peptide-like formula. Pleistocene permafrost-derived DOC exhibited ∼70% loss during the bioincubation driven by its initial molecular-level composition, highlighting its high bioavailability irrespective of microbial source.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 5","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143914102","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}