Global Biogeochemical Cycles最新文献

{"title":"Responses of Riverine Dissolved Organic Carbon to Global Warming and Permafrost Thaw on the Tibetan Plateau","authors":"Yiru Pan,&nbsp;Yi Zhao,&nbsp;Shang Tian,&nbsp;Yichu Wang,&nbsp;Li Yuan,&nbsp;Dongfeng Li","doi":"10.1029/2026GB009157","DOIUrl":"https://doi.org/10.1029/2026GB009157","url":null,"abstract":"<p>Riverine dissolved organic carbon (DOC) plays a vital role in the global carbon cycle, but its spatiotemporal dynamics and controlling mechanisms in alpine permafrost regions remain unclear. Here, by integrating a comprehensive in situ DOC data set, multi-source environmental variables, and machine learning approaches, we reconstruct the riverine DOC concentration (<i>C</i>_DOC) and flux (<i>F</i>_DOC) at five headwater rivers on the eastern Tibetan Plateau (TP) from 2000 to 2024 and investigate their spatiotemporal patterns. Results show that the mean <i>C</i>_DOC across the five rivers is 3.27 ± 0.96 mg/L but remains highly heterogeneous, with higher values observed in the permafrost-dominated headwaters of the Yellow (4.31 ± 0.78 mg/L) and Yangtze Rivers (3.39 ± 0.86 mg/L). The permafrost coverage, soil organic carbon content, and vegetation type shape this spatial pattern. The southeastern rivers (Mekong and Salween Rivers) exhibit declining <i>C</i>_DOC over the past 25 years, primarily driven by soil moisture reduction under climate warming. In contrast, significant <i>C</i>_DOC increases are detected in Yellow (+0.073 mg L⁻¹ decade⁻¹) and Yangtze headwaters (+0.029 mg L⁻¹ decade⁻¹), due to the enhanced vegetation conditions associated with climate warming and permafrost thaw. Total <i>F</i>_DOC at the outlets of major rivers increases markedly, reaching approximately 1.37 Tg yr⁻¹ in response to the rising river discharge. This study presents the spatiotemporal dynamics of DOC across TP rivers, elucidates the underlying mechanisms, and provides a basis for land-river carbon transfer and regional carbon budget assessments in high-elevation permafrost environments.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 8","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148647704","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":"Compound Effects of Warming and Wetting Enhance Soil Respiration on the Earth's Third Pole","authors":"Tongqing Shen,&nbsp;Junliang Jin,&nbsp;Xiaohua Wei,&nbsp;Qin Ju,&nbsp;Guoqing Wang,&nbsp;Yanli Liu,&nbsp;Hui Lin,&nbsp;Shixuan Lyu,&nbsp;Meirong Sun,&nbsp;Changjun Zhu,&nbsp;Jianyun Zhang","doi":"10.1029/2026GB009376","DOIUrl":"https://doi.org/10.1029/2026GB009376","url":null,"abstract":"<p>The temperature sensitivity (<i>Q</i>₁₀) of soil respiration (<i>Rs</i>) is one of the major determinants of carbon emissions from <i>Rs</i>. Identifying the controlling factors of <i>Q</i>₁₀ can contribute to quantifying the response of <i>Rs</i> to climate change and assessing potential carbon emission risks. The Tibetan Plateau (TP), known as the Earth's third pole, plays a pivotal role in the global climate and carbon cycle system. However, the controlling factors of <i>Q</i>₁₀ and its responses to future climate change in this region are not well understood. Here, we introduce a method for calculating <i>Q</i>₁₀ from cumulative carbon emission data on <i>Rs</i>, which allows substantially expanding the available data set. Building on this, we integrate various statistical analyses with explainable machine learning techniques to examine the controlling factors regulating <i>Q</i>₁₀ on the TP. Our analyses consistently show that precipitation and soil potential of Hydrogen are the two most important factors regulating <i>Q</i>₁₀. Precipitation is the dominant factor regulating <i>Q</i>₁₀ across nearly 70% of the plateau, while pH's dominance is about 30%, highlighting the primary role of precipitation as a regulator of <i>Q</i>₁₀ on the TP. Future precipitation increases (wetting) on the TP are predicted to markedly boost the warming-induced increase in <i>Rs</i>, with this effect being particularly pronounced in arid areas. Our findings clearly demonstrate that under future warming and wetting on the TP, the compound effects of precipitation and temperature would enhance <i>Rs</i>, consequently accelerating the soil organic carbon release.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 8","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148617341","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 Carbon Investment in Terrestrial Biological Nitrogen Fixation","authors":"Duncan N. L. Menge,&nbsp;Carla R. Reis Ely,&nbsp;Steven S. Perakis,&nbsp;Sian Kou-Giesbrecht,&nbsp;Cory C. Cleveland,&nbsp;Sasha C. Reed,&nbsp;Benton N. Taylor,&nbsp;Sarah A. Batterman,&nbsp;Timothy E. Crews,&nbsp;Katherine A. Dynarski,&nbsp;Jennifer L. Funk,&nbsp;Maga Gei,&nbsp;Kevin L. Griffin,&nbsp;Michael J. Gundale,&nbsp;David F. Herridge,&nbsp;Sarah E. Jovan,&nbsp;Mark B. Peoples,&nbsp;Johannes Piipponen,&nbsp;Emilio Rodríguez-Caballero,&nbsp;Verity G. Salmon,&nbsp;Fiona M. Soper,&nbsp;Anika P. Staccone,&nbsp;Bettina Weber,&nbsp;Amelia A. Wolf,&nbsp;Nina Wurzburger","doi":"10.1029/2026GB009098","DOIUrl":"https://doi.org/10.1029/2026GB009098","url":null,"abstract":"<p>Biological nitrogen (N) fixation (BNF) provides the N needed to produce proteins and other biological building blocks, helping feed humanity and mitigate climate change. Due to its high energetic cost compared to other forms of N acquisition, biotic investment in BNF indicates N limitation. Globally gridded BNF flux data provide an opportunity to determine the energetic investment in BNF across ecosystems, which would help reconcile conflicting indicators of N limitation. Here, we use a new BNF synthesis to quantify the relative importance of BNF in different N-fixing niches, in different biomes, and across the globe by calculating the fraction of net primary productivity (NPP) invested in BNF and the fraction of plant N acquisition provided by BNF. Larger fractions of non-agricultural NPP were invested in BNF in less-productive, higher-latitude biomes. This pattern was driven by biocrusts and mosses. Similarly, non-agricultural symbiotic N-fixing plants invested relatively more of their own NPP in BNF in less-productive, higher-latitude biomes. This symbiotic plant pattern was driven by shrubs and herbs, overriding the opposite pattern in trees. Symbiotic plants also acquired a higher fraction of their N from BNF at higher latitudes and in less productive biomes. Investments in symbiotic BNF were 10× higher in agricultural (2.9% of NPP) versus natural (0.29%) biomes, providing 26% versus 3.1% of ecosystem-scale plant N acquisition. These results support the paradigm of strong N limitation at higher latitudes, help understand the rarity of N-fixing trees at higher latitudes, underscore the dominance of human activity, and inform terrestrial biosphere models.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 8","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GB009098","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148617111","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 Global Biogeochemical Cycle of Antimony","authors":"Yuanzhi Yao,&nbsp;Feng Wang,&nbsp;Jipeng Xu,&nbsp;Qisheng Zeng,&nbsp;Lijun Hou,&nbsp;Rui Li","doi":"10.1029/2025GB009056","DOIUrl":"https://doi.org/10.1029/2025GB009056","url":null,"abstract":"<p>Antimony (Sb) has emerged as a global environmental concern due to its increasing anthropogenic release and its potential toxicity. This review synthesizes the global Sb biogeochemical cycle, quantifying both natural fluxes and profound anthropogenic perturbations. Natural Sb cycling is driven by rock weathering, atmospheric emissions (2.1 Gg·yr⁻¹), natural deposition, terrestrial vegetation turnover (∼5.64 Gg·yr⁻¹), and riverine export to oceans (37.4 ± 7.8 Gg·yr⁻¹). In the ocean, hydrothermal vents add ∼3.5 ± 2.4 Gg·yr⁻¹, while outputs occur via sediment burial and oceanic lithosphere subduction. Human activities now dominate the cycle, contributing ∼72% of total atmospheric inputs, and the total Sb emission (7.6 Gg·yr⁻¹) increased by 260% compared with the natural emission alone. Mining is the largest disturbance, releasing ∼48.68 Gg·yr⁻¹ into rivers and accumulating ∼66.8 Gg·yr⁻¹ in surrounding soils. Urban wastewater discharges and atmospheric deposition via runoff further contribute to aquatic systems. An estimated total marine input of ∼43.5 Gg·yr⁻¹ slightly exceeds outputs (∼40.5 Gg·yr⁻¹), indicating a human-induced imbalance in the global Sb cycle. Significant uncertainties remain due to scarce emission factors and regional variability, highlighting the need for more precise data to inform sustainable resource management and pollution control strategies.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 7","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616039","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":"Special Collection on Fjords as Aquatic Critical Zones on the Front Lines of Global Change","authors":"Thomas S. Bianchi,&nbsp;Alexander B. Michaud,&nbsp;Candida Savage,&nbsp;Craig Smeaton,&nbsp;Laura M. Wehrmann","doi":"10.1029/2026GB009314","DOIUrl":"https://doi.org/10.1029/2026GB009314","url":null,"abstract":"<p>In this special collection, new studies reveal that fjords serve as vital estuarine transition zones between terrestrial ecosystems and the open ocean. Primarily found at high latitudes, fjords are highly sensitive to climate change, which fundamentally reshapes their land and marine inputs. As glaciers retreat, the influx of freshwater, nutrients, and sediments shifts, altering the chemical and biological makeup of fjord waters. While glaciers currently drive the upwelling of nutrient-rich waters that support primary productivity, glacial retreat onto land may increase stratification and shift ecosystems toward microbial dominance. Fjords also play a critical role in the global climate system as disproportionate hotspots for organic carbon burial. However, warming and melting permafrost threaten to remobilize this stored carbon, potentially changing fjords from carbon sinks into sources of CO₂ emissions. Because of these complex and interacting stressors, fjords are increasingly viewed as “Aquatic Critical Zones” that require urgent interdisciplinary research and management.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 7","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GB009314","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615883","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":"Lateral Coastal Blue Carbon Export Fuels a Deep-Ocean Carbon Sink in an Oligotrophic Warm Pool","authors":"Hsueh-Han Hsieh,&nbsp;Yung-Yen Shih,&nbsp;Chun-Hoe Chow,&nbsp;Tzu-Chieh Chung,&nbsp;Syun-Han Wu,&nbsp;Vicente G. Abedneko,&nbsp;Chin-Hsin Liao,&nbsp;Tse-Min Lee,&nbsp;Jingjing Zhang,&nbsp;Jianfang Chen,&nbsp;Laodong Guo,&nbsp;Hernando P. Bacosa,&nbsp;Chin-Chang Hung","doi":"10.1029/2025GB009034","DOIUrl":"https://doi.org/10.1029/2025GB009034","url":null,"abstract":"<p>Coastal blue carbon (CBC) ecosystems export organic matter offshore, but their contribution to deep-ocean carbon sequestration remains insufficiently quantified. We measured depth-resolved particulate organic carbon (POC) fluxes, δ¹³C signatures, and environmental DNA (eDNA) from sediment traps deployed at 150, 500, and 1,000 m in the western North Pacific warm pool. POC fluxes at 1,000 m were two- to four-fold higher than predicted by classical attenuation models, indicating efficient deep-water transfer driven by both vertical export and lateral inputs. eDNA from sinking particles revealed macroalgae, mangrove, and seagrass taxa throughout the mesopelagic and bathypelagic layers, demonstrating long-distance transport of CBC material. δ¹³C values showed predominantly marine-derived POC, but with measurable CBC contributions persisting at depth. These observations identify a previously underappreciated pathway linking coastal vegetation to deep-ocean carbon storage in oligotrophic gyre systems. They also highlight the need for ground-truth biological carbon pump (BCP) measurements, particularly for oceanic island countries with small land areas yet large exclusive economic zones (EEZs), where accurate carbon accounting depends on in situ validation of model-based estimates.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 7","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GB009034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615882","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":"Nitrous Oxide Emissions Across Sub-Saharan Africa: Meta-Analysis and Data-Driven Modeling","authors":"P. Agredazywczuk,&nbsp;T. Ouma,&nbsp;M. Barthel,&nbsp;A. Otinga,&nbsp;R. Njoroge,&nbsp;K. Butterbach-Bahl,&nbsp;R. Daelman,&nbsp;J. E. Hickman,&nbsp;W. Ibrahim,&nbsp;M. Laub,&nbsp;S. Leitner,&nbsp;A. Shumba,&nbsp;K. L. Tully,&nbsp;S. Wachiye,&nbsp;J. Zheng,&nbsp;M. Bauters,&nbsp;R. Kiese,&nbsp;R. Cardinael,&nbsp;C. Andres,&nbsp;R. Balokah,&nbsp;K. S. Lourenço,&nbsp;K. L. Ouattara,&nbsp;J. Six,&nbsp;E. Harris","doi":"10.1029/2026GB009141","DOIUrl":"https://doi.org/10.1029/2026GB009141","url":null,"abstract":"&lt;p&gt;Food security and avoiding land use change in Sub-Saharan Africa (SSA) requires increasing agricultural productivity, necessitating greater fertilizer use. This may increase soil nitrous oxide (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;O) emissions, a potent greenhouse gas. This study used Machine learning (ML) models to predict &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;O emissions under future climatic and fertilizer scenarios across SSA. Three models were trained (Random Forest (RF), XGBoost (XGB), and feedforward neural networks (FNN)) on existing forest, grassland, and cropland &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;O measurements. The analysis identified the main drivers influencing &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;O emissions: temperature, soil moisture, rainfall, and fertilizer (cropland). SSA &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;O emissions totaled 253–538 Gg N &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mtext&gt;yr&lt;/mtext&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{yr}}^{-1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; (1 Gg = &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mn&gt;10&lt;/mn&gt;\u0000 &lt;mn&gt;9&lt;/mn&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${10}","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 7","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GB009141","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615606","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":"Deep Learning Reconstruction of Daily Soil CO2 Efflux Reveals Biogeochemical Insights and Reduces Annual Estimate Uncertainty Despite Limitated Daily Predictability","authors":"Valerie Smykalov,&nbsp;Ben Bond-Lamberty,&nbsp;Rodrigo Vargas,&nbsp;Li Li","doi":"10.1029/2025GB008899","DOIUrl":"https://doi.org/10.1029/2025GB008899","url":null,"abstract":"<p>Soil CO₂ efflux is commonly measured monthly or seasonally, leaving daily dynamics poorly resolved and contributing to global estimation uncertainty. We trained a single Long Short-Term Memory (LSTM) model to predict daily soil CO₂ efflux across 82 globally distributed sites in COSORE, with 0.2%–46.9% daily data coverage from 2003 to 2020. Despite using far fewer sites than are typically used to train a single deep learning model, with observations biased toward temperate mesic sites, the LSTM model performed well at approximately one-third of sites, reconstructed nearly 2 decades of daily efflux, and outperformed commonly used approaches for estimating daily efflux when applied to the same data set. Performance was weakest at pronounced peaks and troughs and at non-temperate sites with &lt;1.5 years of observations and irregular data patterns. Nevertheless, annual efflux from reconstructed daily data had &lt;40% error even at underperforming sites, substantially improving estimates derived from monthly and seasonal sampling (maximum errors of 95% and 136%, respectively). Temperature sensitivity (<i>Q</i>₁₀) estimated from reconstructed daily predictions closely matched estimates from daily observations, whereas <i>Q</i>₁₀ values derived from monthly or seasonal observations deviated substantially, suggesting that coarse temporal sampling may contribute to uncertainty in reported <i>Q</i>₁₀ values. Consistent daily reconstructions further enabled trend analyses for well-performing, predominantly temperate sites and showed increasing soil CO₂ efflux at most sites from 2003 to 2020, with more variable summer trends. Despite limitations, these results demonstrate the potential of LSTM models to reconstruct daily soil CO₂ efflux and reduce estimation uncertainties from sparse observations.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 7","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GB008899","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615662","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":"Global Patterns on Nutrient Release During Leaf Litter Decomposition in Blue Carbon Ecosystems","authors":"Xiaoguang Ouyang,&nbsp;Erik Kristensen,&nbsp;Martin Zimmer,&nbsp;Carol Thornber,&nbsp;Zhifeng Yang,&nbsp;Shing Yip Lee","doi":"10.1029/2025GB009005","DOIUrl":"https://doi.org/10.1029/2025GB009005","url":null,"abstract":"<p>Nutrient release during litter decomposition is the mineralization of organically bound nutrients into inorganic and soluble forms. However, it remains unknown whether warming increases macro-nutrient release during leaf litter decomposition. Through a global meta-analysis, we incorporated the relationships between nutrient release rate constants (<i>k</i>_NP) and leaf litter decomposition rate constants in coastal blue carbon ecosystems (BCE) into numerical models to forecast nutrient release. Average <i>k</i>_NP ranged from 0.006 to 0.035 d⁻¹ for nitrogen and 0.003–0.019 d⁻¹ for phosphorus with lower values in temperate than (sub)tropical zones. Our findings suggest that nutrient release during leaf litter decomposition will increase with rising temperatures under two scenarios: the IPCC representative concentration pathway 8.5 and the IPCC 1.5–4°C warming compared with the pre-industrial period. Leaf litter nutrient release in mangrove forests and tidal marshes is more sensitive to warming than that in seagrass beds. Leaf litter processing and consumption by benthic fauna during decomposition will lead to lower nutrient release in 2100 compared to 2050 due to global warming. We conclude that warming will intensify, while decreased macrobenthos activity will reduce, leaf litter nutrient release.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 7","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615660","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":"Decadal Shifts Towards Higher Riverine Silicon Relative to Nitrogen and Phosphorus Across High Latitudes","authors":"Joanna C. Carey,&nbsp;Nicholas J. Lyon,&nbsp;Keira Johnson,&nbsp;Pamela L. Sullivan,&nbsp;Sidney A. Bush,&nbsp;Lienne R. Sethna,&nbsp;Ruth Heindel,&nbsp;Pirkko Kortelainen,&nbsp;Hjalmar Laudon,&nbsp;Diane M. McKnight,&nbsp;Amanda Poste,&nbsp;Antti Raike,&nbsp;Kathi Jo Jankowski","doi":"10.1029/2025GB008926","DOIUrl":"https://doi.org/10.1029/2025GB008926","url":null,"abstract":"<p>High-latitude systems are warming faster than the global average, altering the rates of silicon (Si) mobilization from terrestrial to aquatic systems. Dissolved Si (DSi) concentration and its ratio with other nutrients exert strong controls on algae blooms in fresh and marine receiving waters, especially in high-latitude regions where diatoms often dominate riverine and coastal autotroph communities. Here we present an examination of decadal scale changes in river DSi concentrations, loads, and nutrient ratios in 70 high-latitude rivers (&gt;58°) across North America, Europe, Asia, and Antarctica. We examined monthly and annual changes in DSi, dissolved inorganic nitrogen (DIN), and dissolved inorganic phosphorus (DIP) concentrations and yields using sequential breakpoint analysis (i.e., SiZer) that allows for variable trend identification within a single time series. Except for the Antarctic streams, we found a predominant trend of increasing DSi relative to DIN and DIP for both annual concentrations and yields, driven primarily by declines in DIN and DIP rather than increases in DSi. Contrary to expectations, we found little evidence that changes in discharge or shifts in seasonality (i.e., month-specific trends) drove these altered interannual nutrient dynamics. However, interannual changes in DSi concentrations were associated with hydroclimatic variability (precipitation, evapotranspiration, snow cover, air temperature) and DIP availability. Taken together, our analysis identifies large-scale shifts in exports of Si, N, and P in high-latitude rivers, with implications for algae productivity and composition in the highly productive waters of high-latitude ecosystems.</p>","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"40 7","pages":""},"PeriodicalIF":6.9,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GB008926","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148467665","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}