Global Biogeochemical Cycles最新文献

{"title":"Intercropping Legumes Improves Long Term Productivity and Soil Carbon and Nitrogen Stocks in Sub-Saharan Africa","authors":"Kathrin Fuchs,&nbsp;David Kraus,&nbsp;Tobias Houska,&nbsp;Michael Kermah,&nbsp;Edwin Haas,&nbsp;Ralf Kiese,&nbsp;Klaus Butterbach-Bahl,&nbsp;Clemens Scheer","doi":"10.1029/2024GB008159","DOIUrl":"https://doi.org/10.1029/2024GB008159","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Food, feed, and fiber production needs to increase to support demands of the growing population in Sub-Saharan Africa (SSA), while soil fertility continues to decline. Intercropping, the cultivation of two or more crop species on the same field, can provide yield benefits and is suggested to positively affect soil organic carbon (C) and nitrogen (N) stocks. This study uses the biogeochemical model system LandscapeDNDC with the objective to (a) represent maize-legume intercropping systems in different bioregions in SSA by simultaneously simulating both crops and their interactions and (b) assess long-term (20 years) impacts of intercropping under varying mineral fertilizer inputs (0–150 kg N ha⁻¹ yr⁻¹) on productivity as well as soil organic C and N stocks. We test LandscapeDNDC on 82 field data sets (site-year-treatment combinations) from 18 sites to represent yields and soil C/N dynamics of maize-legume intercropping systems. Using the model for long-term scenario simulations showed that intercropping allows to sustain productivity and to improve or maintain SOC stock in low or zero fertilizer systems if all residues are returned to the soil. In contrast, for sole-cropped maize systems, a decline in SOC stocks was simulated unless a minimum of 35 kg N ha⁻¹ yr⁻¹ of fertilizer was applied at full residue return. We conclude that intercropping using legumes alongside sufficient residue return allows for stabilizing long-term yields while avoiding SOC losses even with low fertilizer N inputs. Overall, our study confirms the potential of intercropping as a sustainable agricultural practice that could significantly contribute to food security in SSA.</p>\u0000 </section>\u0000 </div>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008159","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feedbacks From Young Permafrost Carbon Remobilization to the Deglacial Methane Rise","authors":"M. Sabino,&nbsp;Ö. Gustafsson,&nbsp;B. Wild,&nbsp;I. P. Semiletov,&nbsp;O. V. Dudarev,&nbsp;G. Ingrosso,&nbsp;T. Tesi","doi":"10.1029/2024GB008164","DOIUrl":"https://doi.org/10.1029/2024GB008164","url":null,"abstract":"<p>The abrupt warming events punctuating the Termination 1 (about 11.7–18 ka Before Present, BP) were marked by sharp rises in the concentration of atmospheric methane (CH₄). The role of permafrost organic carbon (OC) in these rises is still debated, with studies based on top-down measurements of radiocarbon (¹⁴C) content of CH₄ trapped in ice cores suggesting minimum contributions from old and strongly ¹⁴C-depleted permafrost OC. However, organic matter from permafrost can exhibit a continuum of ¹⁴C ages (contemporaneous to &gt;50 ky). Here, we investigate the large-scale permafrost remobilization at the Younger Dryas-Preboreal transition (ca. 11.6 ka BP) using the sedimentary record deposited at the Lena River paleo-outlet (Arctic Ocean) to reflect permafrost destabilization in this vast drainage basin. Terrestrial OC was isolated from sediments and characterized geochemically measuring δ¹³C, Δ¹⁴C, and lignin phenol molecular fossils. Results indicate massive remobilization of relatively young (about 2,600 years) permafrost OC from inland Siberia after abrupt warming triggered severe active layer deepening. Methane emissions from this young fraction of permafrost OC contributed to the deglacial CH₄ rise. This study stresses that underestimating permafrost complexities may affect our comprehension of the deglacial permafrost OC-climate feedback and helps understand how modern permafrost systems may react to rapid warming events, including enhanced CH₄ emissions that would amplify anthropogenic climate change.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008164","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Role of Acantharia in Southern Ocean Strontium Cycling and Carbon Export: Insights From Dissolved Strontium Concentrations and Seasonal Flux Patterns","authors":"Yaojia Sun,&nbsp;Cathryn A. Wynn-Edwards,&nbsp;Thomas W. Trull,&nbsp;Michael J. Ellwood","doi":"10.1029/2024GB008227","DOIUrl":"https://doi.org/10.1029/2024GB008227","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Dissolved strontium (Sr) concentrations from Southern Ocean water samples and Sr export fluxes from sediment trap moorings at 1,000 m were used to assess particulate organic carbon (POC) export associated with Acantharia for 2010, 2018, and 2020. The dissolved Sr data revealed a prominent vertical gradient with lower surface Sr concentrations depleted up to 1.5% relative to deep waters. A strong latitudinal surface gradient was observed, ranging from 86.8 μmol kg⁻¹ near the northern end to 88.0 μmol kg⁻¹ near the southern end of a transect through the Australian sector of the Southern Ocean. The vertical and latitudinal gradients are associated with celestite (SrSO₄) precipitation by Acantharia and subsequent export to depth. Seasonal variability in Sr export fluxes can be large, particularly during intense events in summer, and reaches a maximum of 11.7 mmol Sr m⁻² yr⁻¹, contributing up to 7% of the POC export flux. The coincidence of Sr flux with the second peak of POC export flux implies an association of Acantharia biomass with summertime productivity.</p>\u0000 </section>\u0000 </div>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Significance of Urea in Sustaining Nitrite Production by Ammonia Oxidizers in the Oligotrophic Ocean","authors":"Xianhui S. Wan,&nbsp;Hua-Xia Sheng,&nbsp;Hui Shen,&nbsp;Wenbin Zou,&nbsp;Jin-Ming Tang,&nbsp;Wei Qin,&nbsp;Minhan Dai,&nbsp;Shuh-Ji Kao,&nbsp;Bess B. Ward","doi":"10.1029/2023GB007996","DOIUrl":"https://doi.org/10.1029/2023GB007996","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Nitrification, the stepwise oxidation of ammonia to nitrate via nitrite, is a key process in the marine nitrogen cycle. Reported nitrite oxidation rates frequently exceed ammonia oxidation rates below the euphotic zone, raising the fundamental question of whether the two steps are balanced and if alternative sources contribute to nitrite production in the dark ocean. Here we present vertically resolved profiles of ammonia, urea, and nitrite oxidation rates and their kinetic traits in the oligotrophic Subtropical North Pacific. Our results show active urea-derived nitrogen oxidation (urea-N oxidation) in the presence of experimental ammonium amendment, suggesting direct urea utilization. The depth-integrated rates of urea-N oxidation and ammonia oxidation are comparable, demonstrating that urea-N oxidation is a significant source of nitrite. The additional nitrite from urea-N oxidation helps to balance the two steps of nitrification in our study region. Nitrifiers exhibit high affinity for their substrates, and the apparent half-saturation constants for ammonia and nitrite oxidation decrease with depth. The apparent half-saturation constant for urea-N oxidation is higher than that for ammonia oxidation and shows no clear vertical trend. Such kinetic traits may account for the relatively higher urea concentration than ammonium concentration in the ocean's interior. Moreover, a compilation of our results and reported data shows a trend of increased urea-N oxidation relative to ammonia oxidation from the eutrophic coastal zone to the oligotrophic open ocean. This trend reveals a substrate-dependent biogeographic distribution of urea-N oxidation across marine environments and provides new information on the balance and flux of the marine nitrification process.</p>\u0000 </section>\u0000 </div>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GB007996","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Incubation Experiments Characterize Turbid Glacier Plumes as a Major Source of Mn and Co, and a Minor Source of Fe and Si, to Seawater","authors":"Xunchi Zhu,&nbsp;Mark J. Hopwood,&nbsp;Katja Laufer-Meiser,&nbsp;Eric P. Achterberg","doi":"10.1029/2024GB008144","DOIUrl":"https://doi.org/10.1029/2024GB008144","url":null,"abstract":"<p>Glaciers are a source of fine-ground rock flour to proglacial and coastal marine environments. In these environments, suspended rock flour may affect light and (micro)nutrient availability to primary producers. Due to high loads of glacier rock flour, the particulate metal load of glacier runoff typically exceeds the dissolved metal load. As glacier rock flour is deposited in downstream environments, short-term exchange between particulate and dissolved metal phases may have a moderating influence on dissolved metal concentrations. Here we compare the behavior of iron (Fe), manganese (Mn), cobalt (Co) and silica (Si) following the addition of different glacier-derived sediments into seawater under conditions of varying sediment load (20–500 mg L⁻¹), time (0.5 hr–21 days), temperature (4–11°C) and light exposure (dark/2,500 Lux). Despite a moderately high labile Fe content across all particle types (0.28–3.50 mg Fe g⁻¹ of dry sediment), only 0.27–7.13 μg Fe g⁻¹ was released into seawater, with less efficient release as sediment load increased. Conversely, Si, Mn, and Co exhibited a more constant rate of release, which was less sensitive to sediment load. Dissolved Si release was equivalent to 17% ± 22% of particulate amorphous Si after 1–2 weeks. Dissolved Mn concentrations in most incubations exceeded dissolved Fe concentrations within 1 hr despite labile Mn content being 12-fold lower than labile Fe content. Our results show the potential for glacier-derived particles to be a large source of Mn and Co to marine waters and add to the growing evidence that Mn may be the bio-essential metal most affected by glacier-associated sources.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008144","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bacterial Community Structure Modulates Soil Phosphorus Turnover at Early Stages of Primary Succession","authors":"Yuhan Wang,&nbsp;Haijian Bing,&nbsp;Daryl L. Moorhead,&nbsp;Enqing Hou,&nbsp;Yanhong Wu,&nbsp;Jipeng Wang,&nbsp;Chengjiao Duan,&nbsp;Qingliang Cui,&nbsp;Zhiqin Zhang,&nbsp;He Zhu,&nbsp;Tianyi Qiu,&nbsp;Zhongmin Dai,&nbsp;Wenfeng Tan,&nbsp;Min Huang,&nbsp;Hans Lambers,&nbsp;Peter B. Reich,&nbsp;Linchuan Fang","doi":"10.1029/2024GB008174","DOIUrl":"https://doi.org/10.1029/2024GB008174","url":null,"abstract":"<p>Microbes are the drivers of soil phosphorus (P) cycling in terrestrial ecosystems; however, the role of soil microbes in mediating P cycling in P-rich soils during primary succession remains uncertain. This study examined the impacts of bacterial community structure (diversity and composition) and its functional potential (absolute abundances of P-cycling functional genes) on soil P cycling along a 130-year glacial chronosequence on the eastern Tibetan Plateau. Bacterial community structure was a better predictor of soil P fractions than P-cycling genes along the chronosequence. After glacier retreat, the solubilization of inorganic P and the mineralization of organic P were significantly enhanced by increased bacterial diversity, changed interspecific interactions, and abundant species involved in soil P mineralization, thereby increasing P availability. Although 84% of P-cycling genes were associated with organic P mineralization, these genes were more closely associated with soil organic carbon than with organic P. Bacterial carbon demand probably determined soil P turnover, indicating the dominant role of organic matter decomposition processes in P-rich alpine soils. Moreover, the significant decrease in the complexity of the bacterial co-occurrence network and the taxa-gene-P network at the later stage indicates a declining dominance of the bacterial community in driving soil P cycling with succession. Our results reveal that bacteria with a complex community structure have a prominent potential for biogeochemical P cycling in P-rich soils during the early stages of primary succession.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Global Biogeochemical Cycle of Rhenium","authors":"L. Ghazi,&nbsp;K. E. Grant,&nbsp;A. Chappaz,&nbsp;M. Danish,&nbsp;B. Peucker-Ehrenbrink,&nbsp;J. C. Pett-Ridge","doi":"10.1029/2024GB008254","DOIUrl":"https://doi.org/10.1029/2024GB008254","url":null,"abstract":"<p>This paper is the first comprehensive synthesis of what is currently known about the different natural and anthropogenic fluxes of rhenium (Re) on Earth's surface. We highlight the significant role of anthropogenic mobilization of Re, which is an important consideration in utilizing Re in the context of a biogeochemical tracer or proxy. The largest natural flux of Re derives from chemical weathering and riverine transport to the ocean (dissolved = 62 × 10⁶ g yr⁻¹ and particulate = 5 × 10⁶ g yr⁻¹). This review reports a new global average [Re] of 16 ± 2 pmol L⁻¹, or 10 ± 1 pmol L⁻¹ for the inferred pre-anthropogenic concentration without human impact, for rivers draining to the ocean. Human activity via mining (including secondary mobilization), coal combustion, and petroleum combustion mobilize approximately 560 × 10⁶ g yr⁻¹ Re, which is more than any natural flux of Re. There are several poorly constrained fluxes of Re that merit further research, including: submarine groundwater discharge, precipitation (terrestrial and oceanic), magma degassing, and hydrothermal activity. The mechanisms and the main host phases responsible for releasing (sources) or sequestrating (sinks) these fluxes remain poorly understood. This study also highlights the use of dissolved [Re] concentrations as a tracer of oxidation of petrogenic organic carbon, and stable Re isotopes as proxies for changes in global redox conditions.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil Carbon Accumulation Under Afforestation Is Driven by Contrasting Responses of Particulate and Mineral-Associated Organic Carbon","authors":"Deping Zhai,&nbsp;Yiyue Wang,&nbsp;Chang Liao,&nbsp;Xiuxian Men,&nbsp;Chi Wang,&nbsp;Xiaoli Cheng","doi":"10.1029/2024GB008116","DOIUrl":"https://doi.org/10.1029/2024GB008116","url":null,"abstract":"<p>Afforestation is widely believed to sequester carbon (C) in soil. However, the effect of afforestation on soil organic C (SOC) accumulation is still debated due to the contrasting features of particulate and mineral-associated organic C (POC and MAOC). We conducted a field investigation of 144 paired sampling sites by comparing afforested and non-afforested lands to investigate the POC and MAOC dynamics after afforestation across the Danjiangkou basin in subtropical China, where forests are dominated by <i>Platycladus orientalis</i>, <i>Quercus variabilis</i> and <i>Pinus massoniana</i>. The average contents of SOC, POC, and MAOC were significantly increased by afforestation; however, POC and MAOC responded differently to afforestation type. All afforestation types promoted the POC content, and MAOC also showed positive responses to afforestation except that afforestation with <i>P</i>. <i>massoniana</i> from shrubland significantly reduced the MAOC content. With increasing SOC content, the POC grew at a faster rate than MAOC at high SOC levels. Afforestation hindered the growth rate of POC, while it promoted the growth rate of MAOC as SOC accrued, which potentially obscured the distinct patterns of C accumulation triggered by afforestation. The variation partitioning suggests that, under afforestation, microbial traits had a higher contribution to both POC and MAOM variations compared with non-afforested land. These results suggest that the robust buildup of microbial biomass due to increased plant C input following afforestation could contribute to soil C accumulation by promoting microbial necromass.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global Estimates of Particulate Organic Carbon Concentration From the Surface Ocean to the Base of the Mesopelagic","authors":"James Fox,&nbsp;Michael J. Behrenfeld,&nbsp;Kimberly H. Halsey,&nbsp;Jason R. Graff","doi":"10.1029/2024GB008149","DOIUrl":"https://doi.org/10.1029/2024GB008149","url":null,"abstract":"<p>The gravitational settling of organic particles from the surface to the deep ocean is an important export pathway and one of the largest components of the ocean carbon pump. The strength and efficiency of the gravitational pump are often measured using metrics reliant on reference depths and empirical formulations that parameterize the relationship between depth and the flux or concentration of particulate organic carbon (POC). Here, BGC-Argo profiles were used to identify the isolume where POC concentration, [POC], starts to decline, revealing attenuation trends below this isolume that are remarkably consistent across the global ocean. We developed a simple empirical approach that uses observations from the first optical depth to predict [POC] from the surface ocean to the base of the mesopelagic (1,000 m), allowing assessments of spatial and temporal variability in gravitational pump efficiencies. We find that rates of [POC] attenuation are high in areas of high biomass and low in areas of low biomass, supporting the view that bloom events sometimes result in a relatively weak deep biological pump that is characterized by low transfer efficiency to the base of the mesopelagic. Our isolume-based attenuation model was applied to satellite data to yield the first remote sensing-based estimate of integrated global POC stock of 3.02 Pg C over the top 1,000 m, with an uncertainty of 0.69 Pg C. Of this total stock, approximately 1.02 Pg was located above the reference isolume where [POC] begins to attenuate.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008149","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gradients of Deposition and In Situ Production Drive Global Glacier Organic Matter Composition","authors":"Amy D. Holt,&nbsp;Amy M. McKenna,&nbsp;Anne M. Kellerman,&nbsp;Tom I. Battin,&nbsp;Jason B. Fellman,&nbsp;Eran Hood,&nbsp;Hannes Peter,&nbsp;Martina Schön,&nbsp;Vincent De Staercke,&nbsp;Michail Styllas,&nbsp;Matteo Tolosano,&nbsp;Robert G. M. Spencer","doi":"10.1029/2024GB008212","DOIUrl":"https://doi.org/10.1029/2024GB008212","url":null,"abstract":"<p>Runoff from rapidly melting mountain glaciers is a dominant source of riverine organic carbon in many high-latitude and high-elevation regions. Glacier dissolved organic carbon is highly bioavailable, and its composition likely reflects internal (e.g., autotrophic production) and external (i.e., atmospheric deposition) sources. However, the balance of these sources across Earth's glaciers is poorly understood, despite implications for the mineralization and assimilation of glacier organic carbon within recipient ecosystems. We assessed the molecular-level composition of dissolved organic matter from 136 mountain glacier outflows from 11 regions covering six continents using ultrahigh resolution 21 T mass spectrometry. We found substantial diversity in organic matter composition with coherent and predictable (80% accuracy) regional patterns. Employing stable and radiocarbon isotopic analyses, we demonstrate that these patterns are inherently linked to atmospheric deposition and in situ production. In remote regions like Greenland and New Zealand, the glacier organic matter pool appears to be dominated by in situ production. However, downwind of industrial centers (e.g., Alaska and Nepal), fossil fuel combustion byproducts likely underpin organic matter composition, resulting in older and more aromatic material being exported downstream. These findings highlight that the glacier carbon cycle is spatially distinct, with ramifications for predicting the dynamics and fate of glacier organic carbon concurrent with continued retreat and anthropogenic perturbation.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"38 9","pages":""},"PeriodicalIF":5.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}