Biogeochemistry最新文献

{"title":"Organic acid concentration thresholds to mobilize phosphorus (P) in dryland soils","authors":"Kalpana Kukreja,&nbsp;Elizabeth Noriega Landa,&nbsp;Wen-Yee Lee,&nbsp;Mark A. Engle,&nbsp;Anthony Darrouzet-Nardi","doi":"10.1007/s10533-025-01298-5","DOIUrl":"10.1007/s10533-025-01298-5","url":null,"abstract":"<div><p>Available phosphorus (P) concentrations are low in dryland soils due to high pH values linked to the presence of pedogenic carbonates. Thus, dissolution and mobilization of P compounds are important controls on P availability for plants, microbes, and biocrusts. One process that has been hypothesized as a way for dryland organisms to acquire P is the exudation of organic acids that can release bound P compounds. To explore this process, we assayed the critical thresholds of organic acid (citrate, malate, and oxalate) concentrations required to mobilize P in a range of dryland soils. Our results showed that: (1) Concentrations of oxalate or citrate, on the order of 1000 µmol/L are needed to effectively mobilize PO₄³⁻ in all landforms and microsites we examined. (2) The in situ organic acid concentrations in bulk soil core samples were &lt; 100 µmol/L, both under plant canopies and in interspaces, suggesting they are below the needed threshold to mobilize P. However, hot spots such as the rhizosphere, though difficult to quantify, may still be locations where the concentration of organic acids approach the threshold. (3) Oxalate was the most effective in releasing PO₄³⁻, likely as a result of removing aqueous Ca via calcium oxalate precipitation. Overall, our results show that for P acquisition through organic acid production to be effective in dryland soils, a relatively high threshold of organic acid concentration that substantially exceeds bulk soil concentrations must be reached, suggesting that if it occurs, it is restricted to localized microsites within the soil matrix.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"169 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01298-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982966","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":"Meltwater as a driver of changing nickel availability in the polar ocean?","authors":"Yaqing Ruan,&nbsp;Jana Krause,&nbsp;Eric P. Achterberg,&nbsp;Nicolas Sanchez,&nbsp;Murat V. Ardelan,&nbsp;Mark J. Hopwood","doi":"10.1007/s10533-025-01292-x","DOIUrl":"10.1007/s10533-025-01292-x","url":null,"abstract":"<div><p>Pelagic dissolved (&lt; 0.2 µm) nickel (dNi) concentrations are rarely depleted below 2 nmol L⁻¹ and normally remain tightly correlated with the macronutrients dissolved silicic acid and phosphate. Nickel is therefore widely disregarded as a possible limit on primary metabolism in modern-day aquatic environments. However, here we demonstrate that low dNi concentrations can arise in some polar regions due to low Ni concentrations in meltwater and thus there are environmental contexts in which Ni availability may plausibly constrain primary producers. Here we characterize the dNi concentrations of meltwater across a range of Arctic localities and present new pelagic measurements from Disko Bay (western Greenland) where previous measurements of dNi indicated the lowest concentrations ever measured in the Arctic or Atlantic. Across 10 (sub)Arctic glacier-fed streams/rivers we find a broad range of mean dNi concentrations from 0.40–132 nmol L⁻¹. Most of the surveyed glacier-fed streams had dNi concentrations within the range 3–13 nmol L⁻¹, which is comparable to major river systems worldwide. Yet three evidenced much lower concentrations with mean dNi &lt; 2 nmol L⁻¹ which would act to dilute dNi concentrations almost anywhere in the ocean. Similarly, meltwater from iceberg fragments in southwest and west Greenland had very low dNi concentrations (mean 0.6 nmol L⁻¹ and 0.2 nmol L⁻¹, respectively). Meltwater therefore appears to be a possible driver of low dNi concentrations, especially when icebergs, rather than runoff enriched with dNi from bedrock weathering, are a dominant freshwater source. However, dNi flux budgets for Arctic fjords reveal that vertical entrainment of deep, Ni-rich waters driven by subglacial discharge plumes often also constitutes a measurable fraction of dNi supply to surface waters, limiting the impact of low-Ni meltwater except under very specific ice-melt stratified scenarios. Whilst in the modern-day ocean there appear to be only limited localized scenarios in which dilution by meltwater might deplete dNi concentrations to levels which could plausibly constrain primary producers, low dNi conditions might have been more prevalent during deglaciation events in Earth’s past when regions of the ocean were stratified by large meltwater fluxes.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01292-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145730306","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":"Higher emissions of carbon dioxide, nitrous oxide, and methane during the daytime in two reservoirs","authors":"E. Leon-Palmero,&nbsp;R. Morales-Baquero,&nbsp;I. Reche","doi":"10.1007/s10533-025-01283-y","DOIUrl":"10.1007/s10533-025-01283-y","url":null,"abstract":"<div><p>Greenhouse gas (GHG) emissions from reservoirs are quantitatively relevant for atmospheric climatic forcing. The magnitude of these fluxes depends on the mechanisms promoting the production of carbon dioxide (CO₂), nitrous oxide (N₂O), and methane (CH₄), and on the physical forces determining their emission. GHG emissions exhibit large temporal variability, with diel changes accounting for a substantial part of this variability. However, most GHG flux estimations rely on upscaling discrete measurements taken at daytime and typically overlook nighttime emissions. This study explored the diel patterns of CO₂, N₂O, and both diffusive and ebullitive CH₄ fluxes in two eutrophic reservoirs with different morphometries, using hourly GHG flux measurements over a summer day in two different years. Daytime emissions of CO₂, N₂O, and diffusive CH₄ were on average 159, 267, and 194% higher than nighttime emissions, respectively. Despite the different production pathways, the diffusive fluxes showed strong daily synchrony, suggesting an external common driver for the three of them. Daily emissions of CO₂, N₂O, and diffusive CH₄ were positive and significantly related to wind speed and solar time. In contrast, ebullitive CH₄ fluxes showed no consistent daily pattern, and were influenced by reservoir management (i.e., water level drawdown) in the shallowest system. Ebullitive CH₄ fluxes represented an average of 51% of the total CH₄ emitted. Our study suggests that diel variability in GHG emissions may be as relevant as spatial or inter-system differences and should be integrated into future GHG budgets to improve their accuracy.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01283-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145729649","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":"Microbial community adaptation to brackish water rewetting in a coastal peatland","authors":"Sara E. Anthony,&nbsp;Nina Schulze,&nbsp;Klaus-Holger Knorr,&nbsp;Dominik H. Zak,&nbsp;Susanne Liebner,&nbsp;Gerald Jurasinski","doi":"10.1007/s10533-025-01297-6","DOIUrl":"10.1007/s10533-025-01297-6","url":null,"abstract":"<div><p>Coastal wetlands can serve as natural laboratories for assessing the future impacts of sea-level rise and the intricacies of the effect of sulfate (SO₄²⁻) on emissions of greenhouse gases, such as methane (CH₄) and carbon dioxide (CO₂). In the case of previously drained and freshened coastal wetlands, we can observe how freshwater terrestrial microbial communities react and adapt to intrusion of SO₄²⁻ rich saline waters. We conducted a 3-month anoxic incubation experiment with soil extracted from a coastal peatland on the German Baltic coast which was rewetted with brackish water in late 2019 to examine how microbial communities at the site had adapted to the new conditions after two years. Soil slurries were incubated at a temperature of 15 °C at two different salinities (reflecting surface water and average peat soil water salinity) and sampled at 8 timepoints. At each timepoint 5 replicates of each treatment were destructively harvested and sampled for concentrations of CH₄, dissolved inorganic carbon (DIC), total aqueous organic carbon, sulfate (SO₄²⁻), ammonium (NH₄⁺), and other major ions, pH values, δ¹³DIC and δ¹³CH₄ values, microbial community composition via 16S rRNA amplicon sequencing and functional gene analysis via shotgun metagenomic sequencing. Carbon, nitrogen, and sulfur elemental analysis (CNS) and X-ray fluorescence (XRF) analysis of soil cores from nearby monitoring locations were included to give background on the biogeochemical conditions of the soil. Contrary to expectations, the legacy of SO₄²⁻ exposure from a previous connection with the Baltic Sea, as evidenced by high sulfate concentrations, was the strongest influence on the biogeochemistry of each treatment, rather than the new salinity and SO₄²⁻ introduced during rewetting. The different salinities tested had little impact on the methane emissions as the microbial community was already well adapted to saline and SO₄²⁻-rich conditions and displayed a considerable amount of functional gene equivalency. We conclude from our results that we need to pay more attention to the legacy effects in coastal peatlands and how they affect methane cycling and microbial community composition for years to decades.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01297-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778676","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":"Vegetation type influences particulate organic matter storage along a low Arctic vegetation gradient","authors":"Lewis Sauerland,&nbsp;Rica Wegner,&nbsp;Andrei Moise,&nbsp;Lukas Kohl,&nbsp;Jenie Gil,&nbsp;Birgit Wild","doi":"10.1007/s10533-025-01294-9","DOIUrl":"10.1007/s10533-025-01294-9","url":null,"abstract":"<div><p>Permafrost soils constitute a large part of the terrestrial carbon pool that is vulnerable to future climate warming. Continued warming of the low Arctic is also leading to the encroachment of large shrubs and trees into tundra ecosystems with effects on microbial community composition, organic matter cycling and physical soil parameters. To date it is still largely unknown how such vegetation shifts affect soil organic matter cycling in permafrost soils on short and long timescales. Here, we investigated differences in soil organic matter properties under graminoid tussock (<i>Eriophorum vaginatum</i>), birch shrub (<i>Betula glandulosa</i>), spruce tree (<i>Picea mariana</i>) and alder shrub (<i>Alnus viridis</i>) vegetation by density fractionation and subsequent measurements of organic carbon, total nitrogen, δ¹³C, and lignin phenol biomarker contents. Particulate organic matter constituted 1.3–11.3% of soil weight and stored between 29 and 89% of the total soil lignin, 12–60% of organic carbon and 6–40% of total nitrogen. The contribution of particulate organic matter generally decreased with soil depth. Soils under <i>Alnus viridis</i> showed significantly higher amounts of particulate organic matter and stored more lignin, organic carbon and total nitrogen in particulate form in all soil depths. Sites dominated by <i>Eriophorum vaginatum</i> exhibited higher lignin content and lower degradation state in the subsoil, which was associated with water saturation and low active layer depth. We conclude that the effect of vegetation changes on soil organic matter cycling is dependent on plant species with the encroachment of <i>Alnus viridis</i> shrubs potentially increasing the deposition of particulate organic matter into permafrost soils.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01294-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145771500","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":"Relations of the O-horizon with canopy tree species and hydropedologic soil types","authors":"Elizabeth A. Studer,&nbsp;Scott W. Bailey,&nbsp;Balthasar L. von Hoyningen Huene,&nbsp;Caitlin E. Hicks Pries,&nbsp;Matthew P. Ayres","doi":"10.1007/s10533-025-01290-z","DOIUrl":"10.1007/s10533-025-01290-z","url":null,"abstract":"<div><p>As the interface between plants and soil, the organic horizon is the foundation of forest ecosystems. Two potential predictors of O-horizon properties, vegetation and mineral soil type, are difficult to separate because they typically covary. We conducted a factorial study involving four canopy tree species and two soil types with different hydrology and topographic position to parse patterns in chemistry and microbiota of the O-horizon in a north-temperate deciduous forest. There were frequent strong effects of tree species. Organic horizon properties under white ash frequently differed from the other trees: e.g., lower cation exchange capacity and exchangeable acidity, thinner Oi horizon, lower %C and C:N, and, from phospholipid fatty acids, more AM fungi and less gram positive bacteria. These patterns, presumably due to species-specific attributes of leaf litter quality, root exudates, and microbial associations, must arise over decades, given that the forest stands that we studied were established only 85—100 years ago. We also found patterns in the O-horizon related to underlying soil type, independent of tree species: e.g., Bh podzols, compared to typical podzols, had higher trace metals, thicker Oa horizon, and more AM fungi. Relationships between mineral soil type and the organic horizon could arise because landscape features that influence hydrology and therefore soil formation over centuries also influence biogeochemistry of the organic horizon over decades. It could also involve bioturbation by organisms across horizons. There is basic and applied value in better understanding of properties of the O-horizon based on vegetation and soil types.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"169 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01290-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982403","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":"Taking the heat: soil warming optimum of CH4 uptake in subarctic mineral soils","authors":"Annelie Skov Nielsen,&nbsp;Linsey Marie Avila,&nbsp;Bjarni D. Sigurdsson,&nbsp;Klaus Steenberg Larsen,&nbsp;Jesper Riis Christiansen","doi":"10.1007/s10533-025-01287-8","DOIUrl":"10.1007/s10533-025-01287-8","url":null,"abstract":"<div><p>Atmospheric methane (CH₄) uptake in subarctic and Arctic mineral soils is significant for the CH₄ budget of high-latitude regions, but its response to warming is not well understood. The effect of soil warming on net CH₄ uptake was studied in situ across a natural warming gradient (ambient to +  57.5 °C) in a geothermal area in Southwest Iceland. The study site represented a subarctic grassland on mineral soil with field measurements conducted in summer and fall 2021. Combined automatic and manual dynamic chamber CH₄ flux measurements across the warming transect showed that net CH₄ uptake increased with 0.26 nmol CH₄ m⁻² s⁻¹ per 1 °C of soil warming from ambient soil temperature up to about + 4 °C of soil warming. Soil warming above + 4 °C resulted in a gradual decrease of net CH₄ uptake corresponding to 0.1 nmol CH₄ m⁻² s⁻¹ per 1 °C of soil warming up to + 13 °C . With further soil warming, in situ net CH₄ fluxes were probably affected by geogenic emissions during the effective study period. These trends of enhanced in situ net CH₄ uptake with mild soil warming followed by a decreasing uptake rate with further warming were confirmed in a laboratory incubation experiment showing that the in situ response to temperature &lt;  + 13 °C was biogenic rather than geogenic. It is still not known whether the observed trends are due to adaptation of the community structure to temperature, differential regulation of activity or abundance. Our findings point to a window of future soil warming up to about + 4 °C where net CH₄ uptake in subarctic grassland mineral soils is likely to increase, while further soil warming may result in a decrease of this important CH₄ sink below ambient level. To expand the representativeness of these findings, we encourage future studies to include similar incubation experiments of the warming response for soils across the Arctic.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"169 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01287-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new framework for interpreting ex situ wetland methane production and consumption rates","authors":"Satya Kent,&nbsp;Genevieve L. Noyce,&nbsp;Paul Dijkstra,&nbsp;Egbert Schwartz,&nbsp;Bruce A. Hungate","doi":"10.1007/s10533-025-01293-w","DOIUrl":"10.1007/s10533-025-01293-w","url":null,"abstract":"<div><p>Ex situ incubations are the primary method used to quantify rates of gross methane production and consumption, which together determine net wetland methane emissions. However, a clear framework for interpreting these data is lacking, and it remains uncertain whether ex situ rates and their environmental drivers conform to expectations from in situ ecological theory. We synthesized published rates of methanogenesis, aerobic methane oxidation, and anaerobic methane oxidation and used boosted regression tree models to identify key drivers. We found median aerobic methane oxidation rates were 2.7 times greater than those of methanogenesis—a paradox given wetlands are net methane sources. This discrepancy arises from methodological artifacts: aerobic methane oxidation is measured as a potential rate, resulting in overestimation, whereas methanogenesis is largely measured as a substrate-limited rate, resulting in underestimation. This conclusion is grounded in our finding that potential methanogenesis rates were an order of magnitude higher than their substrate-limited counterparts (p &lt; 0.001). Our driver analysis indicates that 1. rates of methanogenesis are strongly controlled by labile carbon availability from the soil surface, 2. the balance between methanogenesis and anaerobic methane oxidation is shifting with warming, and 3. species-specific plant effects structure all pathways of methane production and consumption via rhizosphere interactions. This synthesis demonstrates the value of ex situ data for generating mechanistic hypotheses while highlighting the need for future research to prioritize in situ measurements to obtain accurate rate estimates.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"169 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01293-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145848036","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":"Local controls rather than short-term drought regulate microbial phosphorus and greenhouse gas dynamics in floodplain sediments","authors":"Michele Meyer,&nbsp;Matthias Koschorreck,&nbsp;Markus Weitere,&nbsp;David Kneis,&nbsp;Daniel Graeber,&nbsp;Nuria Perujo","doi":"10.1007/s10533-025-01295-8","DOIUrl":"10.1007/s10533-025-01295-8","url":null,"abstract":"<div><p>River floodplain systems are challenged by drought, which may trigger excess nutrient concentrations and greenhouse gas emissions. Increasingly frequent short-term droughts may exacerbate both problems by altering hydrological connectivity and thereby restructuring microbial communities and dissolved organic matter (DOM), which, in combination, may regulate sediment phosphorus and methane release. However, the combined effects of drought and connectivity on phosphorus and methane release via changes in DOM composition and microbial activity remain poorly understood. We incubated sediments from three floodplain sites along a hydrological connectivity gradient to the River Elbe and subjected them to two short-term drought intensities, corresponding to sediment moisture losses of 0.5–2.5% (moderate drought) and 19–21% (intense drought), followed by rewetting. Drought had surprisingly limited effects on phosphorus and methane release, while the site had a consistently higher impact and shaped the direction and magnitude of drought effects. Moreover, our results suggest that fluxes may be more pronounced at sites that were formerly well-connected to the river. Phosphorus was released under oxic conditions and was linked to heterotrophic microbial carbon use and humic-like DOM, implying that the effects of DOM-mediated microbial activity on phosphorus release need to be considered in future research efforts. Our findings suggest that long-term changes in hydrological connectivity, like lower discharge and changed DOM delivery, could have stronger effects on nutrient dynamics and microbial processes than short-term drought. Preserving floodplain connectivity is therefore critical to limiting nutrient and greenhouse gas release under climate change.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01295-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145730203","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":"Linking thermal stability and organic chemistry with soil organic matter stability: a study across ecozones","authors":"Moazame Mesgar,&nbsp;Edward G. Gregorich,&nbsp;Mike H. Beare,&nbsp;Craig F. Drury,&nbsp;Benjamin H. Ellert,&nbsp;Tom Z. Regier,&nbsp;Amanda Diochon,&nbsp;Omid H. Ardakani,&nbsp;Adam W. Gillespie","doi":"10.1007/s10533-025-01289-6","DOIUrl":"10.1007/s10533-025-01289-6","url":null,"abstract":"<div><p>Understanding the stability of soil organic matter (SOM) is central to predicting soil carbon persistence and informing sustainable land management. We combined thermal, chemical, and biological approaches to evaluate SOM stability in 108 soils spanning diverse ecozones in Canada, New Zealand, Scotland, and the Subarctic. Thermal stability was measured using Rock–Eval (RE) pyrolysis, chemical composition was characterized with X-ray absorption near-edge structure (XANES) spectroscopy, and biological stability was assessed through 98-day C mineralization assays. Across soils, thermal stability (T50) was strongly and negatively correlated with mineralized C, indicating that stronger bond structures reduce biodegradability. Importantly, our results demonstrate that T50 not only reflects SOM quality but also serves as a proxy for the extent of organo-mineral associations that contribute to stabilization. The Hydrogen Index (HI) showed a positive relationship with mineralized C, confirming its role as a reliable indicator of labile SOM. XANES results further revealed that alkyl-C and the alkyl/O-alkyl-C ratio were positively related to thermal stability, whereas ketones and aromatic groups correlated negatively with T50, suggesting they are labile byproducts of microbial decomposition or contributions from lignin and tannins, rather than highly recalcitrant aromatic compounds typically associated with stable SOM. Together, these findings highlight that SOM persistence is shaped by both intrinsic chemical composition and extrinsic mineral protection. Rock–Eval pyrolysis and XANES spectroscopy thus provide complementary insights into SOM stability and, when combined with biological assays, offer generalizable tools for evaluating soil carbon resilience across ecosystems.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 6","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01289-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145561604","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}