Journal of Geophysical Research: Biogeosciences最新文献_第4页

Hydrologic Management Convolutes Expected Spatiotemporal Patterns of Dissolved Organic Matter in the Hudson River 水文管理使哈德逊河中溶解有机质的预期时空模式复杂化

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-04-03 DOI: 10.1029/2024JG008131

Alex C. Collins, Julia Hubbard, Sasha Wagner

{"title":"Hydrologic Management Convolutes Expected Spatiotemporal Patterns of Dissolved Organic Matter in the Hudson River","authors":"Alex C. Collins, Julia Hubbard, Sasha Wagner","doi":"10.1029/2024JG008131","DOIUrl":"https://doi.org/10.1029/2024JG008131","url":null,"abstract":"Riverine dissolved organic matter (DOM) is a vector for nutrient cycling and elemental exchange between terrestrial and oceanic reservoirs. The quality and quantity of DOM transported in rivers are determined by a complex interplay of watershed-specific conditions (e.g., land use and discharge). In many temperate rivers, the frequency and intensity of hydrologic events are expected to increase with continued climate change, which would result in an overall increased export of terrestrial DOM. However, the presence of dams and other impoundments increase water residence time and could dampen these effects. Here, we examine DOM biogeochemistry in the Hudson River (New York, USA), which experiences intermittent periods of elevated discharge and receives a seasonally varied series of inputs from urban, agricultural, and forested landscapes. DOM was quantified and characterized using optical spectroscopic techniques, including parallel factor analysis (PARAFAC) modeling of fluorescent DOM components. Our findings indicate that the influence of land cover on DOM composition is secondary to that of hydrologic management. We also found DOM pulse-shunt effects to be more muted in the upper Hudson River watershed, where more water is retained by dams and reservoirs than in the Mohawk River watershed. Regardless of hydrologic management, discharge events consistently enhanced aromatic DOM export in the Hudson River and its subbasins, which suggests climate change and increased rainfall will enhance the delivery of humic-like DOM to the estuary and coastal margins.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 4","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761921","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}

引用次数: 0

Exploring the Signature of Lipid Biomolecules Influenced by Soil Aggregates Across Terrestrial Ecosystems 陆地生态系统土壤团聚体对脂类生物分子特征的影响

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-04-02 DOI: 10.1029/2024JG008424

Biswajit Roy, Twismary Kharphuli, Disha Baidya, Prasanta Sanyal

{"title":"Exploring the Signature of Lipid Biomolecules Influenced by Soil Aggregates Across Terrestrial Ecosystems","authors":"Biswajit Roy, Twismary Kharphuli, Disha Baidya, Prasanta Sanyal","doi":"10.1029/2024JG008424","DOIUrl":"https://doi.org/10.1029/2024JG008424","url":null,"abstract":"Soils across terrestrial ecosystems comprise aggregates with varying biological and physicochemical properties that impact plant lipid distribution. This study examines the role of aggregates characteristics in the distribution of n-alkyl lipids (n-alkanes and n-alkanoic acids) in forest, grassland, and mixed (shrubs and grasses) ecosystems across five different particle size fractions (PSF) in the lower Ganga region (India). Fresh plant-derived n-alkyl lipid signature, similar to the bulk soil, mostly associates sand PSF (>63 μm), which constitutes larger aggregates formed by extensive biological (fungal hyphae and roots) and physical (clay coating) components. Fragmented soil aggregates comprise mostly the silt PSF, which allowed restricted storage of plant n-alkyl lipids and increased microbial contribution. Stable clay-rich microaggregates in finer PSF (<20 μm) vary across ecosystems, influencing the storage and modification of plant-derived n-alkyl lipid signatures. Principle component analysis showed that the n-alkyl lipid signature across PSF in forest soil is distinct and more variable than other two ecosystems. In grassland and mixed PSF, extensive belowground root processes fragments and reduces soil aggregates, which limits the modification of plant n-alkyl lipids when compared to physically stable aggregates found in forest ecosystems. The susceptibility of n-alkanoic acids to microbial decomposition resulted in consistent replacement and a stable profile across soil fractions, while n-alkanes exhibit greater variability due to differences in aggregate protection. Such difference in biochemical response between n-alkyl lipids highlights the crucial role of aggregate characteristics in mineral protection and/or microbial decomposition of OM, which contributes to microscale carbon dynamics across ecosystems.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 4","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749348","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}

引用次数: 0

Using a Plant Hydrodynamic Model, FETCH4, to Supplement Measurements and Characterize Hydraulic Traits in a Mixed Temperate Forest 利用植物水动力学模型FETCH4补充测量和表征混合温带森林的水力特征

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-03-30 DOI: 10.1029/2024JG008198

Justine E. C. Missik, Gil Bohrer, Madeline E. Scyphers, Ashley M. Matheny, Ana Maria Restrepo Acevedo, Marcela Silva, Golnazalsadat Mirfenderesgi, Yair Mau

{"title":"Using a Plant Hydrodynamic Model, FETCH4, to Supplement Measurements and Characterize Hydraulic Traits in a Mixed Temperate Forest","authors":"Justine E. C. Missik, Gil Bohrer, Madeline E. Scyphers, Ashley M. Matheny, Ana Maria Restrepo Acevedo, Marcela Silva, Golnazalsadat Mirfenderesgi, Yair Mau","doi":"10.1029/2024JG008198","DOIUrl":"https://doi.org/10.1029/2024JG008198","url":null,"abstract":"Species-specific hydraulic traits play an important role in ecosystem response to water stress; however, representation of biodiverse forest canopies remains a challenge in land surface models. We introduce FETCH4, a multispecies, canopy-level, hydrodynamic model, which builds upon previous versions of the finite-difference ecosystem-scale tree crown hydrodynamics model (FETCH). FETCH4 simulates water transport through the soil, roots, and stem as porous media flow. Stomatal conductance is controlled by xylem water potential, which is resolved along the vertical dimension. A key feature of FETCH4 is a multispecies canopy formulation, which uses crown and stem dimensional characteristics to allow the model to produce both tree-level and plot-level outputs and improves the representation of hydraulic traits and their variation among trees and species. We demonstrate the model's performance in a mixed temperate forest in Michigan with species of contrasting hydraulic strategies. We optimize species-specific hydraulic parameters using a Bayesian optimization framework incorporating sapflow measurements. FETCH4 performed well in simulating sapflow of species with contrasting hydraulic strategies under conditions of water stress. In addition, the model was able to capture higher-level emergent traits, such as drought sensitivity. Using FETCH4 in combination with available observations can provide unique insights about difficult to measure hydraulic traits and plant hydrodynamics.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 4","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008198","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143741353","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}

引用次数: 0

On the Relationship Between Methane Production in Anaerobic Incubations of Peat Material and In Situ Methane Emissions 泥炭材料厌氧培养产甲烷与原位甲烷排放关系的研究

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-03-29 DOI: 10.1029/2024JG008371

Alexandra B. Cory, Rachel M. Wilson, Olivia C. Ogles, Patrick M. Crill, Zhen Li, Kuang-Yu Chang, Samantha H. Bosman, Virginia I. Rich, Jeffrey P. Chanton, EMERGE Project Coordinators, Moira Hough, Sky Dominguez, Nicole Irwin-Raab, Gareth Trubl, Robert M. Jones, Darya Anderson, Isogenie Field Team

{"title":"On the Relationship Between Methane Production in Anaerobic Incubations of Peat Material and In Situ Methane Emissions","authors":"Alexandra B. Cory, Rachel M. Wilson, Olivia C. Ogles, Patrick M. Crill, Zhen Li, Kuang-Yu Chang, Samantha H. Bosman, Virginia I. Rich, Jeffrey P. Chanton, EMERGE Project Coordinators, Moira Hough, Sky Dominguez, Nicole Irwin-Raab, Gareth Trubl, Robert M. Jones, Darya Anderson, Isogenie Field Team","doi":"10.1029/2024JG008371","DOIUrl":"https://doi.org/10.1029/2024JG008371","url":null,"abstract":"Anaerobic incubations of peat have been widely used to explore soil processes, but this in vitro technique raises many questions as to how well it reproduces in situ conditions. To investigate this, we conducted 60–100 days (+25 days pre-incubation) anaerobic, temperature-controlled incubation experiments across a temperature range of 1–26°C on samples from bog and fen habitats, at two different depths (9–19and 25–35 cm). We observed exponential increases in CO2 and methane production with temperature in all conditions. We then compared field-based measurements of methane emission with modeled expectations by extrapolating incubation-determined methane production rates based on (a) soil temperature profiles, (b) the observed incubation temperature-methane production relationship, and (c) seasonal thaw depth from each site. The resulting incubation-extrapolated methane production agreed with measured emission rates within a factor of two at both sites and corresponded to 182 ± 54% and 59 ± 14% of the measured average yearly fluxes from the field for the bog and fen, respectively. The underestimation of fen methane fluxes may be due to the lack of living plant root-derived dissolved organic carbon inputs in incubations, a key process in fens. Conversely, the overestimation in bogs could be attributed to methane oxidation in the field, which is absent in anaerobic incubation conditions. Nonetheless incubations predicted greenhouse gas emissions from a northern peatland within a factor of two.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 4","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143726777","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}

引用次数: 0

Nitrogen Processes Within Tropical Mangroves in Australia 澳大利亚热带红树林中的氮过程

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-03-27 DOI: 10.1029/2024JG008335

M. F. Adame, N. Iram, J. N. Gamboa-Cutz, P. Masque

{"title":"Nitrogen Processes Within Tropical Mangroves in Australia","authors":"M. F. Adame, N. Iram, J. N. Gamboa-Cutz, P. Masque","doi":"10.1029/2024JG008335","DOIUrl":"https://doi.org/10.1029/2024JG008335","url":null,"abstract":"Coastal wetlands have long been identified as ecosystems that can ameliorate N inputs into the ocean. The processes associated with N uptake, transformation, and losses are relatively well understood for temperate wetlands; however, information on tropical wetlands is scarce. In this study, we conducted a whole ecosystem approach to measure N processes within tropical mangroves in the Moresby estuary in northeast Australia. We measured N stocks (trees and soils), inputs from sedimentation, fixation, and accumulation as woody biomass, and outputs through denitrification, anammox, and soil respiration (N2O emissions). Potential denitrification was detected along anammox (average, min-max) at 883 (485–1,450) gN ha−1 day−1, followed by sediment accumulation with 108 (0–375) gN ha−1 day−1, and tree uptake with 93 (13–153) gN ha−1 day−1. Lower rates were found for N fixation with 45 (0–260) gN ha−1 day−1 and soil respiration as N2O with uptakes of −0.36 (−2.7 – 0.40) gN ha−1 day−1. Overall, mangroves in the Moresby estuary are fixing some N in their standing litter while removing NO3 and NH4+ from the water column through denitrification and anammox, temporarily storing N as woody biomass, and accumulating particulate N in their sediments. These mangroves are also functioning as sinks of N2O. Thus, the protection and restoration of these mangroves provide water quality and climate benefits.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 4","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008335","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707494","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}

引用次数: 0

Assessing the Molecular-Level Controls of Dissolved Organic Matter Cycling in West Siberian Lowland Rivers 西伯利亚西部低地河流溶解有机质循环的分子水平控制

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-03-27 DOI: 10.1029/2024JG008537

Martin R. Kurek, Oleg S. Pokrovsky, Ivan V. Krickov, Artem G. Lim, Mikhail А. Korets, Robert G. M. Spencer

{"title":"Assessing the Molecular-Level Controls of Dissolved Organic Matter Cycling in West Siberian Lowland Rivers","authors":"Martin R. Kurek, Oleg S. Pokrovsky, Ivan V. Krickov, Artem G. Lim, Mikhail А. Korets, Robert G. M. Spencer","doi":"10.1029/2024JG008537","DOIUrl":"https://doi.org/10.1029/2024JG008537","url":null,"abstract":"The West Siberian Lowland (WSL) contains some of the largest wetlands and most extensive peatlands on Earth, storing vast amounts of vulnerable carbon across permafrost-free to continuous permafrost zones. As temperature and precipitation changes continue to alter the Siberian landscape, carbon transfer to the atmosphere and export to the Arctic Ocean will be impacted. However, the drivers of organic carbon transfer are largely unknown across this region. We characterized seasonal dissolved organic carbon (DOC) concentration and dissolved organic matter (DOM) composition of WSL rivers from the middle reaches of the Ob’ River in the permafrost-free zone, as well as tributaries of the Taz River in the northern continuous permafrost zone. DOC and aromatic DOM properties increased from spring to autumn in the Ob’ tributaries, reflecting the seasonal transition from groundwater-sourced to terrestrial DOM. Differences in molecular-level signatures via ultra-high resolution mass spectrometry revealed the influence of redox processes on DOM composition in the winter while terrestrial DOM sourcing shifted from surface litter aliphatics and highly unsaturated and phenolic high-O/C (HUPHigh O/C) compounds in the spring to subsurface soils and HUPLow O/C compounds by autumn. Furthermore, aromaticity and organic N were related to landscape properties including peatlands, forest cover, and the ratio of needleleaf:broadleaf forests. Finally, the Taz River tributaries were similar to summer and autumn Ob’ tributaries, but more enriched in N and S-containing compounds. These signatures were likely derived from thawing permafrost, which we expect to increase in northern rivers due to active layer expansion in a warming Arctic.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 4","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717253","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}

引用次数: 0

Changes in Aquatic Carbon Following Rewetting of a Nutrient-Poor Northern Peatland 营养贫乏的北方泥炭地再湿润后水生碳的变化

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-03-27 DOI: 10.1029/2024JG008565

Alberto Zannella, Karin Eklöf, Eliza Maher Hasselquist, Hjalmar Laudon, Mark H. Garnett, Marcus B. Wallin

{"title":"Changes in Aquatic Carbon Following Rewetting of a Nutrient-Poor Northern Peatland","authors":"Alberto Zannella, Karin Eklöf, Eliza Maher Hasselquist, Hjalmar Laudon, Mark H. Garnett, Marcus B. Wallin","doi":"10.1029/2024JG008565","DOIUrl":"https://doi.org/10.1029/2024JG008565","url":null,"abstract":"Rewetting drained peatlands by raising the groundwater table is currently suggested, and widely implemented, as an efficient measure to reduce peat soil degradation and decrease CO2 emissions. However, limited information exists regarding effects of peatland rewetting on lateral carbon export (LCE) via the aquatic pathway. Any changes in LCE are critical to consider, as they affect the overall peatland C balance, and may offset any climatic benefits from rewetting. Additionally, altered LCE could have consequences for downstream water quality and biota. Here, we monitored aquatic C content (DOC, DIC and CH4) in runoff and pore water, as well as radiocarbon content of DOC in runoff from a drained, nutrient-poor boreal peatland that was rewetted during autumn 2020. By comparing pre- (2019–2020) and post- (2021–2022) rewetting periods, we detected changes in the aquatic C export. The results showed that the rewetting effect was site-, season- and C form-specific. Overall, one catchment showed elevated (DOC, DIC) or highly elevated (CH4) concentrations and exports post-rewetting, whereas the other site showed only elevated DOC. Changes in runoff C concentrations after rewetting were likely driven by site-specific factors such as expansion of open-water areas, altered hydrological flow paths and proportion of filled in ditches of total ditch length. Finally, radiocarbon measurements indicated enhanced export of contemporary DOC via runoff following rewetting. These initial (short-term) findings highlight the need for site-specific before-after assessments to better evaluate the C sequestration capacity of peatlands while undergoing rewetting operations.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 4","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008565","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717254","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}

引用次数: 0

Investigating Spatial and Temporal Nitrogen Dynamics in a Forested Headwater Stream Over the Course of an Annual Drying Event 在一个年度干旱事件过程中研究森林源流中氮的时空动态

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-03-27 DOI: 10.1029/2024JG008522

Kaci Zarek, C. Nathan Jones, Delaney M. Peterson, Stephen Plont, Arial J. Shogren, Corianne Tatariw, Shannon L. Speir, Behzad Mortazavi, Amy J. Burgin

{"title":"Investigating Spatial and Temporal Nitrogen Dynamics in a Forested Headwater Stream Over the Course of an Annual Drying Event","authors":"Kaci Zarek, C. Nathan Jones, Delaney M. Peterson, Stephen Plont, Arial J. Shogren, Corianne Tatariw, Shannon L. Speir, Behzad Mortazavi, Amy J. Burgin","doi":"10.1029/2024JG008522","DOIUrl":"https://doi.org/10.1029/2024JG008522","url":null,"abstract":"Headwater streams make up nearly 80% of the stream network by length and play an important role in shaping the physical, chemical, and biological functions of downstream waters. In the Southeastern US, these systems are beginning to experience increases in the frequency and duration of drying, but it is unclear how increased drying will impact downstream water quality. To begin to address this issue, we examined nitrogen dynamics in a forested headwater stream across an annual drying event. The annual drying event was divided into seasonal wet (March–June), dry-down (June–October), and rewet (November–March) periods. We used a combination of water quality sensors at the watershed outlet, spatially distributed synoptic sampling of net denitrification conditions and physicochemical variables across the watershed, and a series of denitrification potential experiments to examine variation in biogeochemical state across the annual drying event. At the watershed outlet, nitrate concentrations were positively correlated with increased watershed-scale connectivity during the rewet period, while nitrate concentrations were positively correlated with increased streamflow during the dry-down period. Throughout the watershed, net denitrification conditions varied more across seasons than space, with greater net denitrification conditions during the dry-down period. Further, net denitrification conditions were positively correlated to stream temperature, nitrate, and ammonium concentrations but inversely related to streamflow. Finally, denitrification measurements confirmed the dry-down period experienced the highest denitrification rates. Our results highlight the connection between stream drying and nitrogen dynamics in humid systems, providing key information for developing predictive understanding of headwater streams.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 4","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707496","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}

引用次数: 0

Nitrate Loads and Concentrations From Forested Watersheds and Implications for Long Island Sound 森林流域的硝酸盐负荷和浓度及其对长岛海峡的影响

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-03-27 DOI: 10.1029/2024JG008489

Alana B. Spaetzel, James B. Shanley, Leslie A. DeSimone, John R. Mullaney

{"title":"Nitrate Loads and Concentrations From Forested Watersheds and Implications for Long Island Sound","authors":"Alana B. Spaetzel, James B. Shanley, Leslie A. DeSimone, John R. Mullaney","doi":"10.1029/2024JG008489","DOIUrl":"https://doi.org/10.1029/2024JG008489","url":null,"abstract":"Reduction in point sources of nitrogen has led to improvement in water quality of the Long Island Sound (LIS) since 2000, but changes in nonpoint sources are less clear. A significant yet poorly quantified nonpoint nitrogen source is the forested landscape. Because a large proportion of the LIS basin is forested, even small areal inputs from the forested landscape have a large cumulative effect on nitrogen loading to LIS. Atmospheric nitrogen deposition, the primary source of nitrogen to forested landscapes in LIS basin, has been declining for several decades. However, nitrogen export in streams does not necessarily mirror nitrogen deposition. To assess forest nitrogen export to LIS, we estimated annual average concentrations and fluxes of nitrate in 17 forested watersheds in and near the LIS basin. Average flow-normalized nitrate-nitrogen concentrations ranged from less than 0.05–0.43 mg per liter among all sites; annual flow-normalized yields ranged from 0.45 to 4.3 kg per hectare. Flow-normalized annual average concentrations and yields of nitrate between water years 1991–2021 did not monotonically increase or decrease at most watersheds. Where determined, the other major N species generally had comparable magnitude and trends. Based on the watersheds analyzed in this study, forested areas are not responding uniformly to the continued decline of atmospheric nitrogen deposition. The variability among sites may indicate that local-scale factors exert substantial influence over the magnitude and trends in nitrogen exports. One watershed that had increasing development showed an increasing trend in nitrate, but not in dissolved organic nitrogen.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 4","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008489","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717252","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}

引用次数: 0

Seasonally Dynamic Dissolved Carbon Cycling in a Large Hard Water Lake 大型硬水湖中的季节性动态溶解碳循环

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2025-03-22 DOI: 10.1029/2024JG008645

Margot E. White, Benedict V. A. Mittelbach, Nicolas Escoffier, Timo M. Y. Rhyner, Negar Haghipour, David J. Janssen, Marie-Elodie Perga, Nathalie Dubois, Timothy I. Eglinton

{"title":"Seasonally Dynamic Dissolved Carbon Cycling in a Large Hard Water Lake","authors":"Margot E. White, Benedict V. A. Mittelbach, Nicolas Escoffier, Timo M. Y. Rhyner, Negar Haghipour, David J. Janssen, Marie-Elodie Perga, Nathalie Dubois, Timothy I. Eglinton","doi":"10.1029/2024JG008645","DOIUrl":"https://doi.org/10.1029/2024JG008645","url":null,"abstract":"Inland waters play a crucial role in the global carbon cycle, with lakes integrating carbon from various sources within their catchment in addition to that fixed by local primary productivity. Isotopic measurements of carbon pools can differentiate contributions from these sources, with natural abundance radiocarbon (14C) a particularly powerful tool due to the large range in 14C characteristics among carbon sources. Here, we present 14C measurements of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) from monthly water column samplings over the course of a year in Lake Geneva, a large oligotrophic hard water perialpine lake in Western Europe. We find that DIC in the lake is significantly 14C-depleted relative to the atmosphere primarily due to the dissolution of carbonate rocks in the lake's catchment. Variability in DI14C is largely tied to the Rhône River inflow, where DI14C values were also found to vary seasonally. DOC has a 14C signature similar to that of DIC, reflecting the fact that much of the lake DOC pool is autochthonous. However, more 14C-depleted DOC was observed in July and tied to increased river discharge from snow and glacier melt within the upper Rhône River basin. These observations shed light on carbon sources and dynamics within Lake Geneva and its alpine catchment and highlight the importance of preaged dissolved carbon inputs to the largest natural lake in Western Europe.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008645","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689431","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}

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