Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Balance Between Biomixing and Bioirrigation Behavior Controls Benthic Metal Efflux in Temperate Swedish Fjords","authors":"Cathrin Wittig,&nbsp;Martine Leermakers,&nbsp;Per O. J. Hall,&nbsp;Astrid Hylén,&nbsp;Mikhail Kononets,&nbsp;Ulrike Braeckman,&nbsp;Sebastiaan J. van de Velde","doi":"10.1029/2026JG010194","DOIUrl":"https://doi.org/10.1029/2026JG010194","url":null,"abstract":"<p>Iron and manganese availability limits marine primary production in large parts of the ocean and exerts a strong influence on the global climate. Transitional systems such as fjords can control metal transport to the shelf by acting as metal sinks through burial or metal sources by releasing metals from less reactive metal oxides by benthic recycling. Benthic metal cycling is promoted by bioturbation by macrobenthos, which rework the sediment (‘biomixing’) and ventilate their burrows (‘bioirrigation’). The specific role of bioturbation in pore water mobilization, benthic efflux, or burial of metals in fjords is poorly constrained. Here, we investigated the bioturbation mode and potential to mobilize metals in three fjord systems with different environmental conditions in southwestern Sweden using a combined field sampling and modeling approach. We show that the extent to which the bioturbation zone overlaps with the microbial metal reduction zone in the sediments, together with the ratio of biomixing versus bioirrigation rates, determined whether the studied transitional system acted as a sink or source for metals. The efficiency of pore water mobilization of metals was primarily controlled by benthic metal recycling and subsurface oxidation. Including the bioturbation mode and its attenuation depth is thus critical for future investigations of benthic metal cycling, efflux and transport in transitional systems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JG010194","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149206206","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":"Fluxes Versus Pools: Connecting Temperature Dependence and Sensitivity of Soil Carbon Dynamics Across Timescales","authors":"Salvatore Calabrese,&nbsp;Shibli Sadik Tulip,&nbsp;Sherlynette Pérez Castro,&nbsp;Aaron Thompson,&nbsp;Jennifer Pett-Ridge,&nbsp;Zivko Nikolov","doi":"10.1029/2026JG009818","DOIUrl":"https://doi.org/10.1029/2026JG009818","url":null,"abstract":"&lt;p&gt;As global temperatures rise, predicting changes in soil organic carbon (SOC) pools and fluxes requires understanding the temperature &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $(T)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; responses of the key underlying biotic and abiotic mechanisms. Inconsistent terminology—particularly the use of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $T$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; &lt;i&gt;dependence&lt;/i&gt; and &lt;i&gt;sensitivity&lt;/i&gt;—and varying methodological emphases on SOC &lt;i&gt;pools&lt;/i&gt; versus &lt;i&gt;fluxes&lt;/i&gt; can hinder the integration of experimental results with process-based models aimed at mechanistic insights into the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $T$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; response of SOC processes. Here, after re-emphasizing the distinction between &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $T$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; dependence (function relating a SOC flux or pool to &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $T$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $T$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; sensitivity (i.e., its &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $T$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; derivative), we illustrate how the apparent &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $T$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; responses of SOC pools and heterotrophic respiration emerge from the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $T$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; response of individual SOC fluxes. We then analyze SOC dynamics using experimental data and novel SOC modeling frameworks, examining both steady-state and transient responses, including the change in heterotrophic respiration following a step-change in &lt;span&gt;&lt;/spa","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JG009818","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149205835","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 Dynamics and Biogeochemical Signatures in Lakes From the Prairies to Tundra in Western Canada","authors":"Vilmantas Prėskienis,&nbsp;E. Henriikka Kivilä,&nbsp;Matthew J. Bogard,&nbsp;Dënë Cheecham-Uhrich,&nbsp;Jules M. Blais,&nbsp;Milla Rautio","doi":"10.1029/2025JG009558","DOIUrl":"https://doi.org/10.1029/2025JG009558","url":null,"abstract":"<p>Climate-driven poleward shifts of terrestrial ecosystems are expected to alter organic matter inputs and biogeochemical processes in northern lakes. In regions lacking long-term observations, latitudinal gradients provide valuable space-for-time substitutions for predicting these changes. We sampled water columns and sediments from 23 lakes across six ecoregions spanning the Canadian Prairies, boreal forest, and tundra to identify spatial patterns in organic matter composition, carbon burial, and dissolved greenhouse gases (GHG; notably CO₂, CH₄, and N₂O). Catchment characteristics strongly influenced lake biogeochemistry by regulating terrestrial organic matter inputs and water column mixing. Lakes along the southern treeline exhibited the highest sediment GHG concentrations, co-occurring with abundant labile allochthonous organic matter, long warm summers, and conditions favoring thermal stratification. In contrast, exposed Prairie and tundra lakes remained well-mixed and displayed similar biogeochemical characteristics despite contrasting climates. We further noticed increased algal (particularly cyanobacterial) and methanogenic production in lakes with catchments recently affected by extensive wildfires, suggesting that wildfires may further amplify climate-driven changes in northern lake ecosystems. Our findings highlight the strong coupling between terrestrial ecosystems and freshwater biogeochemistry, improving our ability to predict how lake carbon cycling may respond to future northward shifts of terrestrial ecosystems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009558","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149205569","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":"Source or Sink? Precipitation Shapes Future Terrestrial Carbon Uptake in Australia","authors":"Alison C. Bennett,&nbsp;Ian N. Harman,&nbsp;Damien Irving,&nbsp;Peter R. Briggs,&nbsp;Josep Canadell,&nbsp;Marcus Thatcher","doi":"10.1029/2026JG009820","DOIUrl":"https://doi.org/10.1029/2026JG009820","url":null,"abstract":"<p>Nature-based CO₂ removal must deliver sequestration beyond background terrestrial uptake and be resilient to future climate change. Regional-scale simulations of future terrestrial carbon cycles are needed to establish baselines, map spatial variation in carbon uptake, and guide placement of nature-based carbon removal projects. Using Australia as a case study, spanning biomes from tropical to semi-arid, we simulated Australia’s future terrestrial carbon cycle (2015–2100) using a land-surface model under low (SSP1-2.6) and high (SSP3-7.0) emissions scenarios (14 simulations). Simulations indicate that Australia is likely to remain a carbon sink in this century although sink strength is uncertain and strongly linked to variability in precipitation projections. Under SSP3-7.0, cumulative carbon uptake ranged from 2.0 to 14.2 Pg C with end-of-century sequestration rates between 0.01 and 0.22 Pg C yr⁻¹. Under SSP1-2.6, uptake was lower, ranging from −0.7 to 12.2 Pg C with rates between −0.2 and 0.04 Pg C yr⁻¹. Precipitation was the strongest correlate with carbon uptake, whereas CO₂ played a secondary role. Few regions consistently increased uptake across all climate futures, whereas several “hotspots” of decline were identified in southeastern and southwestern Australia. Interannual variability in carbon uptake is projected to increase in the savanna and sparsely vegetated biomes. Our results highlight challenges in identifying regions for nature-based carbon removal and indicate a weakening terrestrial carbon sink under emissions pathways aligned with Paris agreement goals. This study underscores the value of regional-scale simulations for informing policies to enhance carbon sinks and the critical importance of precipitation projections to future carbon dynamics.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JG009820","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149205568","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":"Prescribed Fire Mitigates Climate-Driven Aboveground Carbon Losses From Wildfire in High Elevation Ecosystems of the Sierra Nevada","authors":"Ash B. Cale,&nbsp;Jianning Ren,&nbsp;William Burke,&nbsp;Maureen C. Kennedy,&nbsp;Benjamin W. Sullivan,&nbsp;Erin J. Hanan","doi":"10.1029/2026JG009930","DOIUrl":"https://doi.org/10.1029/2026JG009930","url":null,"abstract":"<p>Extreme wildfires are becoming more common in California's Sierra Nevada, increasing the need for fuel management to protect ecosystem services such as carbon storage. Because mechanical treatments can be costly or inaccessible in steep or remote terrain, prescribed fire, particularly broadcast burning, provides a cost-effective strategy for treating large, forested areas. However, managers must weigh the immediate carbon costs of treatment against the longer-term benefits of reduced fire severity. These trade-offs are difficult to estimate from historical data alone, as climate change is actively reshaping fire regimes. We used the coupled ecohydrological-fire regime model (RHESSys-WMFire) to examine how climate change and prescribed fire influence future fire regimes and carbon dynamics in a high-elevation, mixed conifer watershed. We simulated historical conditions and three future climate scenarios, each with and without prescribed fire, in a factorial design. Climate change increased watershed aridity, producing smaller but more frequent fires. Untreated locations that were historically mesic experienced higher future fire hazard because they had accumulated high fuel loads while simultaneously becoming more arid. In these locations, prescribed fire effectively reduced fire size and hazard. However, under the hottest and driest climate scenario, climate-driven increases in fire hazard exceeded reductions achieved through prescribed burning. Prescribed fire also reduced wildfire-driven carbon losses, particularly in scenarios with greater precipitation variability. Overall, our findings suggest that prescribed fire can reduce fire hazard and enhance carbon retention in fire-prone, climate change-impacted landscapes, though its effectiveness may be limited under extreme warming and drying.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JG009930","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146153","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":"Patterns and Drivers of Mercury Accumulation in Croplands, a Meta-Analysis","authors":"Jenna M. Hynes,&nbsp;Heidi Hausermann,&nbsp;Jacqueline R. Gerson","doi":"10.1029/2025JG009227","DOIUrl":"https://doi.org/10.1029/2025JG009227","url":null,"abstract":"<p>Mercury (Hg) is a potent neurotoxin that poses risks to human and environmental health, particularly in regions influenced by anthropogenic Hg emissions. Although Hg emissions have declined across North America and Europe following regulatory controls and phase-outs, emissions remain elevated in some regions due to activities such as artisanal and small-scale gold mining (ASGM), coal combustion, and non-ferrous metal mining, which occur near croplands. Here, we present the first global synthesis of Hg cycling in croplands through a meta-analysis of reported total Hg concentrations in edible crop biomass and a comparison with Hg accumulation patterns reported for natural vegetation systems. Across studies, root (2.87 ± 0.12 mg kg⁻¹ dw) and leafy vegetables (1.53 ± 0.04 mg kg⁻¹ dw) exhibited higher total Hg concentrations than other crop types (<i>p</i> &lt; 0.01), suggesting that differences in crop physiology and dominant uptake pathways contribute to Hg accumulation. Most crop types also had significantly higher total Hg concentrations (<i>p</i> &lt; 0.001) than non-crop vegetation (e.g., lichen, wood, and grass), likely because crop studies largely originated from contaminated sites. These patterns suggest that local contamination intensity, crop type, soil physicochemical properties (e.g., pH, nutrients), and agricultural management practices (e.g., organic amendments and crop rotation) all influence crop Hg concentrations. We conclude by identifying critical knowledge gaps regarding Hg cycling in croplands and outlining future research priorities to improve food safety assessments, better understand Hg uptake mechanisms, and develop management strategies to reduce Hg exposure through crops.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG009227","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146399","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":"Land-Cover Dynamics and Their Influence on Surface Temperature Across India: Evidence From Forest–Open Thermal Contrasts","authors":"Jyoti Sharma,&nbsp;Pankaj Kumar,&nbsp;Alexander J. Winkler","doi":"10.1029/2026JG009940","DOIUrl":"https://doi.org/10.1029/2026JG009940","url":null,"abstract":"<p>Large and ongoing land-cover (LC) transitions alter the surface energy balance and land surface temperature (LST) across India. Because a single location can undergo successive LC changes, assessing only the initial and final states obscures intermediate dynamics, while temporal LST trends over such transitions fail to separate effects from background climate variability. To address these gaps, we apply a matrix-based framework to quantify year-by-year LC transitions (2001–2022) and combine it with a moving-window approach across major biodiversity hotspots to robustly isolate forest–open land thermal contrasts under similar climatic and geographic conditions. Results show that cropland exhibits the largest net expansion, followed by forest (+3.4 thousand km² yr⁻¹), primarily at the expense of grassland and savanna, while urban land expands irreversibly. Although savanna contributes most to forest gains, substantial forest losses also occurred toward savanna, indicating asymmetric, bidirectional forest-savanna class transitions. Forests are consistently cooler than adjacent open land, with mean daytime ΔLST (forest–open) ranging from −1.28 ± 0.02°C to −2.24 ± 0.05°C (<i>p</i> &lt; 0.05), peaking in summer. However, open land is cooling more rapidly than forests over time, indicating forest thermal inertia, and this differential cooling weakened the forest–open thermal contrast at 0.021°C yr⁻¹ (<i>p</i> &lt; 0.001). Variations in daytime ΔLST are partly explained by evapotranspiration and albedo contrasts and show significant statistical associations with net primary productivity, with these factors together explaining up to 41% of the variance. These findings highlight forest cooling and the need for context-specific management that conserves both forests and savannas.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149205418","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":"Responses of Ecosystem Water Use Efficiency to Diversified Crop Rotations in the Inland Pacific Northwest of the United States","authors":"Jingyu Yao,&nbsp;Muxian Chen,&nbsp;Jiagui Huang,&nbsp;Yuexi Ma,&nbsp;Zhongming Gao,&nbsp;Yongjiu Dai,&nbsp;Eric Russell,&nbsp;Shelley Pressley","doi":"10.1029/2026JG010166","DOIUrl":"https://doi.org/10.1029/2026JG010166","url":null,"abstract":"<p>With intensifying global warming and water scarcity worldwide, improving ecosystem water use efficiency (WUE) is critical for the sustainable development of rain-fed dryland agriculture. Diversified crop rotations represent a promising agronomic strategy to optimize carbon-water coupling and improve stress tolerance. Using 3-year continuous eddy-covariance observations for three representative rotation systems in the semi-arid Inland Pacific Northwest, USA, this study investigated how diversified rotations regulate ecosystem-scale WUE, with a focus on the mediating role of canopy conductance (Gc). Ecosystem WUE was jointly governed by crop-rotation regime, air temperature, and soil water content, largely through Gc-dependent physiological pathways. The four dominant crop species exhibited divergent hydrothermal adaptation thresholds and physiological response strategies. The winter wheat–spring wheat–winter pea rotation maintained the highest and most stable annual WUE (2.67 g C kg⁻¹ H₂O), accompanied by a moderate WUE decline during compound drought-heat extremes. By comparison, the rotations incorporating garbanzo achieved lower WUE and diminished stress resilience. Vapor pressure deficit constrained Gc across all crop types, while soil moisture shaped WUE indirectly by altering canopy physiological conditions. Divergent hydrothermal adaptive traits among constituent crops offer a plausible mechanistic explanation for the superior functional performance of the optimal rotation system. These findings illustrate that well-designed cereal-legume rotations can optimize canopy-level physiological functioning, strengthen ecosystem carbon-water coupling, and improve the resistance of semi-arid agroecosystems to compound drought-heat stress. This study provides physiological insights and actionable rotational management guidance for developing water-saving and stress-adapted cropping systems across global water-limited dryland regions.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146317","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":"Air–Water Greenhouse Gases Exchange in Surface Waters of Deception Island (South Shetland Archipelago, Antarctica): Assessment of Drivers of Spatial Variability","authors":"S. Amaya-Vías,&nbsp;A. Brusselman,&nbsp;B. Delille,&nbsp;M. de la Paz,&nbsp;M. Díez-Minguito,&nbsp;S. Flecha,&nbsp;O. Belyaev,&nbsp;G. Navarro,&nbsp;A. Tovar-Sánchez,&nbsp;I. E. Huertas","doi":"10.1029/2026JG009811","DOIUrl":"https://doi.org/10.1029/2026JG009811","url":null,"abstract":"<p>Greenhouse gases (GHGs) such as Carbon Dioxide (CO₂), Methane (CH₄), and Nitrous Oxide (N₂O) play critical roles in global climate change. CO₂ dominates due to its high concentration and long atmospheric lifetime, while CH₄ and N₂O also exert strong heat-trapping effects despite shorter residence times. Deception Island, in the Southern Ocean, combines active volcanism with extensive penguin colonies, offering a unique setting to quantify natural GHG sources. This study provides concentrations and fluxes of GHGs in an inner bay, coastal and external ocean fringes and freshwater systems to assess the role of volcanic and biological activity on the emissions. Sampling included measurements of partial pressure of CO₂ (<i>p</i>CO₂), CH₄, N₂O and biogeochemical variables, such as Dissolved Oxygen, pH, Total Alkalinity (<i>A</i>_<i>T</i>), Dissolved Organic Carbon, Temperature (T) and Salinity (S). Results revealed high spatial variability in GHG concentrations in marine systems, where <i>p</i>CO₂ ranged from 181 to 25,000 μatm, CH₄ exceeded 400 nM and N₂O varied from negligible levels to 50 nM. Overall, most areas acted as net GHG sources to the atmosphere, with maximum fluxes of CO₂ and CH₄ in volcanic sites reaching 1,300 and 0.5 mmol m⁻² d⁻¹, respectively. Elevated CH₄ (&gt;50 mmol m⁻² d⁻¹) and N₂O (&gt;2 mmol m⁻² d⁻¹) effluxes were also found in endorheic ponds located inside penguin colonies, thereby indicating that these birds play a significant role in natural GHG emissions. These findings highlight that complex geological and biological processes drive significant GHG emission variability in the region and underscore the need to refine global estimates from remote environments.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JG009811","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146390","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":"Warming Amplifies the Variability of Methane Emissions From a Coastal Wetland","authors":"Abigail S. L. Lewis,&nbsp;Roy L. Rich,&nbsp;Genevieve L. Noyce","doi":"10.1029/2026JG009973","DOIUrl":"https://doi.org/10.1029/2026JG009973","url":null,"abstract":"<p>Climate warming is expected to increase methane (CH₄) emissions from coastal wetlands, but its effects on the temporal dynamics of emissions remain poorly resolved. Because short-lived high-emission events are poorly captured by low-frequency monitoring and by existing models, warming-driven increases in variability could worsen a systematic bias in CH₄ budget estimates. Here, we analyzed the effects of soil warming on flux variability using an in situ warming experiment in a brackish coastal wetland. We found that warming-driven increases in CH₄ emissions disproportionately resulted from an increase in emissions during infrequent extreme events (top 0.2%–5% of fluxes) that are unlikely to be captured in low-frequency monitoring. These high flux events include ebullitive (bubbling) events, which were more common and influential at higher soil temperatures. Consequently, simulated monthly sampling underestimated total emissions by a greater percentage under elevated soil temperatures (+5.7°C; 29% underestimate) compared with ambient temperatures (3.4% underestimate). While warming was associated with increases in the variability of CH₄ fluxes across all temporal scales (hourly, daily, weekly, and seasonal), the change in short-term (hourly) variability was proportionally greater than the change in seasonal variability, highlighting the increased importance of rapid-scale emission dynamics under warming. Hourly and daily variability in emissions were predominantly associated with variability in water level, while the seasonal pattern of emissions was related to seasonal changes in soil temperature. Combined, our results indicate that understanding and modeling future CH₄ dynamics may require accounting for an increasing magnitude of CH₄ emitted during short-lived periods of high emission in a warming climate.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"131 10","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146035","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}