Global Change Biology最新文献

{"title":"Hydroxyl Radical-Driven Oxidation as a Key Pathway for Greenhouse Gas Production During Soil Drying–Rewetting","authors":"Xing Guo,&nbsp;Yongxing Lu,&nbsp;Jungang Yang,&nbsp;Fan Du,&nbsp;Yakov Kuzyakov,&nbsp;Yuanhe Yang,&nbsp;Shen Yu,&nbsp;Shuping Qin,&nbsp;Qinglong Fu,&nbsp;Xiaoying Rong,&nbsp;Benfeng Yin,&nbsp;Kai Shi,&nbsp;Xiangfang Lv,&nbsp;Yuanming Zhang,&nbsp;Xiaobing Zhou","doi":"10.1111/gcb.70552","DOIUrl":"10.1111/gcb.70552","url":null,"abstract":"<div>\u0000 \u0000 <p>The drying-rewetting of soil can increase the release of greenhouse gases over a short time period and is one of the key pathways for greenhouse gas emissions in many terrestrial ecosystems, particularly in drylands. The mechanisms underlying this pulse of greenhouse gas emissions remain nearly unknown. Here, we conducted simulated soil rewetting experiments using typical cover of dryland soils (bareland, cyanobacteria/lichen-covered soil, and moss-covered soil). The ¹³C, ¹⁵N, and ¹⁸O labeling techniques allowed to explore the intrinsic mechanisms of rapid carbon (C) and nitrogen (N) release from the soils following rewetting. We found that the hydroxyl radical (˙OH) was produced after soil rewetting via the rapid activation of microorganisms. The carbon dioxide (CO₂) and nitrous oxide (N₂O) production strongly decreased after ˙OH removal, whereas the methane (CH₄) production was not affected. The synergistic action between ˙OH oxidation and microbial enzymatic reactions increased CO₂ production. The ˙OH also stimulated the oxidation of NH₄⁺ to NO₃⁻ and dominated the N₂O production. Our results confirm the role of ˙OH in the production of greenhouse gases and indicate that microbially mediated ˙OH oxidation mechanisms are an overlooked key pathway for the emission of greenhouse gases during the soil rewetting. In the context of climate change, the extreme weather-induced drying-rewetting cycles in soils are becoming more frequent, making greenhouse gas emissions via the ˙OH oxidation pathway increasingly important.</p>\u0000 </div>","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Demystifying the Romanticized Narratives About Carbon Credits From Voluntary Forest Conservation","authors":"Thales A. P. West,&nbsp;Kelsey Alford-Jones,&nbsp;Philippe Delacote,&nbsp;Philip M. Fearnside,&nbsp;Ben Filewod,&nbsp;Ben Groom,&nbsp;Clemens Kaupa,&nbsp;Andreas Kontoleon,&nbsp;Tara L'Horty,&nbsp;Benedict S. Probst,&nbsp;Federico Riva,&nbsp;Claudia Romero,&nbsp;Erin O. Sills,&nbsp;Britaldo Soares-Filho,&nbsp;Da Zhang,&nbsp;Sven Wunder,&nbsp;Francis E. Putz","doi":"10.1111/gcb.70527","DOIUrl":"10.1111/gcb.70527","url":null,"abstract":"<p>Carbon offset projects aimed at avoiding deforestation and forest degradation, generally labeled “REDD+,” are frequently promoted as a pivotal tool to mitigate climate change, promising to offer additional co-benefits for biodiversity and local communities. Despite this optimism, most positive impacts claimed by these initiatives in the voluntary carbon market (VCM) lack empirical support and are instead based on the hopeful narratives of stakeholders with clear conflicts of interest. We critically examine the scientific theories, concepts, and evidence regarding VCM's REDD+ projects, highlighting limitations on the quantification of their purported benefits that are inherent to the current design of carbon markets. Independent studies consistently point to shortcomings in the rigor and credibility of crediting methodologies and other procedures, which market players have been slow or reluctant to address. There is accumulating evidence that projects' climate and social impacts are often exaggerated due to a range of technical and practical shortcomings. We hope this work clarifies widespread misconceptions associated with REDD+ projects in the VCM and assists organizations and policymakers in their efforts to meaningfully mitigate climate change.</p>","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.70527","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Insights Into Water Vapor Uptake by Dry Soils Using a Global Eddy Covariance Observation Network","authors":"Sinikka J. Paulus,&nbsp;Mirco Migliavacca,&nbsp;Markus Reichstein,&nbsp;Rene Orth,&nbsp;Sung-Ching Lee,&nbsp;Arnaud Carrara,&nbsp;Anke Hildebrandt,&nbsp;Jacob A. Nelson","doi":"10.1111/gcb.70547","DOIUrl":"10.1111/gcb.70547","url":null,"abstract":"<p>The exchange of water vapor between soil and atmosphere is a key component of land–atmosphere interactions, especially under dry conditions. Soil water vapor adsorption (SVA) occurs when the atmospheric water vapor pressure is greater than the soil air vapor pressure, which triggers the transport of water vapor from the atmosphere to the soil and its retention on the soil particle surface in liquid form. This process is largely caused by soil hydraulic properties and may play a significant role in dryland hydrology, yet remains understudied due to a lack of continuous, direct observations. In this study, we use globally distributed eddy covariance flux tower data to detect and characterize patterns of soil water vapor adsorption. We verify the consistency between negative latent heat fluxes as an indicator of water vapor movement toward the ground and the theoretical understanding of SVA. Our results reveal a relationship between the direction of the vapor gradient, as indicated by the direction of the latent heat flux, soil moisture, and near-surface relative humidity, which is consistent with the understanding of a phase equilibrium at the pore scale of the soil. Distinguishing between random noise and physically explainable occurrences of negative latent heat fluxes enables the characterization of SVA occurrence in eddy covariance observations. SVA is detected most frequent in arid and semi-arid regions, particularly in ecosystems with sparse vegetation such as savannas and dry shrublands. On average, SVA occurs for 4 ± 1.1 h per night, and may last up to 7 h in some locations. In certain sites, SVA occurs on more than 150 nights per year. These findings suggest that the eddy covariance method can help monitor SVA occurrence. Mapping the spatiotemporal patterns of SVA enhances our understanding of dryland land–atmosphere water fluxes and uncovers a previously overlooked component of the terrestrial water cycle.</p>","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.70547","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Widespread but Divergent Drought Legacy Effects on Gross Primary Productivity Across Biomes","authors":"Xin Yu,&nbsp;René Orth,&nbsp;Markus Reichstein,&nbsp;Christian Reimers,&nbsp;Ulisse Gomarasca,&nbsp;Mirco Migliavacca,&nbsp;Dario Papale,&nbsp;Michael Bahn,&nbsp;Ana Bastos","doi":"10.1111/gcb.70541","DOIUrl":"10.1111/gcb.70541","url":null,"abstract":"<p>Drought can impact terrestrial ecosystems concurrently but also lagged in time, that is, through legacy effects. Drought legacy effects have been identified in parameters such as tree radial growth or satellite-based greenness. Evidence in ecosystem-scale fluxes, for example, gross primary productivity (GPP), is emerging, but still limited to individual sites or specific regions. Based on GPP data at 76 long-term (≥ 7 years) eddy-covariance sites across climates and biomes, we found drought legacy effects for 26 out of 52 droughts, with magnitudes comparable to the drought concurrent effects and lasting typically up to 1 year following drought. These effects diverged in direction: 19 events led to reduced GPP in the following years (negative legacy effects), while 7 showed increased GPP (positive legacy effects). Forests experienced more negative legacy effects than non-forest ecosystems. Legacy effects were more pronounced in forests with higher hydraulic vulnerability. Our findings demonstrate the global relevance of drought legacy effects on GPP and the need for their integration into drought impact assessments.</p>","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.70541","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145260839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Mapping Resilient Landscapes to Climate Change in a Megadiverse Country","authors":"Milena Fermina Rosenfield,&nbsp;Lucas Jardim,&nbsp;Marina Antongiovanni,&nbsp;Luciano Carramaschi de Alagão Querido,&nbsp;Alisson André Ribeiro,&nbsp;Andrea Sánchez-Tapia,&nbsp;Priscila Silveira,&nbsp;Levi Carina Terribile,&nbsp;Eduardo M. Venticinque,&nbsp;Ana Luisa Albernaz,&nbsp;Letícia Couto Garcia,&nbsp;Leandro Reverberi Tambosi,&nbsp;Marcos Adami,&nbsp;Fernando Gertum Becker,&nbsp;Maíra Benchimol,&nbsp;Luísa Gigante Carvalheiro,&nbsp;Cintia Cornelius,&nbsp;Geraldo Alves Damasceno-Junior,&nbsp;Ricardo Dobrovolski,&nbsp;Manuel Eduardo Ferreira,&nbsp;Carlos Roberto Fonseca,&nbsp;José Guilherme Fronza,&nbsp;Angela Terumi Fushita,&nbsp;Adrian Antonio Garda,&nbsp;Heinrich Hasenack,&nbsp;Priscila Lemes,&nbsp;Renata Libonati,&nbsp;Camile Lugarini,&nbsp;Marcia C. M. Marques,&nbsp;Felipe Melo,&nbsp;Alessandro Ribeiro de Morais,&nbsp;Sandra Cristina Müller,&nbsp;Andreza Viana Neri,&nbsp;Rita de Cássia Quitete Portela,&nbsp;Mario Barroso Ramos Neto,&nbsp;Camila Linhares Rezende,&nbsp;Fabio de Oliveira Roque,&nbsp;Thadeu Sobral-Souza,&nbsp;Mariana M. Vale,&nbsp;Gustavo M. Vasques,&nbsp;Eduardo Vélez-Martin,&nbsp;Ima Vieira,&nbsp;Fernanda P. Werneck,&nbsp;Edenise Garcia","doi":"10.1111/gcb.70544","DOIUrl":"10.1111/gcb.70544","url":null,"abstract":"<p>The effects of global climate change on biodiversity and ecosystem functioning are unevenly distributed in the geographic space. Identifying sites more suitable to sustain biodiversity in a changing climate is essential to both species conservation and restoration strategies at different scales. Here, we map terrestrial climate-resilient sites for biodiversity across Brazil to identify sites with greater chances of providing suitable conditions for species to persist under regional climate change. Our mapping combines spatial metrics based on landscape heterogeneity, a proxy for microclimatic variability, and local connectedness, a measure of connectivity between habitats, to determine landscape resilience, assuming that resilience to climate change will be greater the more heterogeneous the characteristics of local habitats are and the more connected they are in the landscape. Our results show that within each biome, medium to high resilient sites are mostly found in the Amazon (40% of the biome) and Pantanal (38%). Low resilience, conversely, is concentrated in the Atlantic Forest (41% of the biome), followed by Cerrado (37%), Pampa (36%), and Caatinga (34%). Landscape resilience information has the potential to be used to effectively guide decision-making and public policy on strategies for conservation, restoration, and sustainable use practices. Priority for conservation should be on high resilience sites as they have the potential to sustain biodiversity in face of undergoing and future climate change. Other approaches could be used in situations of medium to low resilience also, such as: conservation of current corridors in sites with high local connectedness, but low landscape heterogeneity; restoration of natural vegetation on sites that show high landscape heterogeneity, but low local connectedness; and sustainable practices in areas of low resilience. Our study provides an updated method to pinpoint climate-resilient sites for biodiversity which was applied to a megadiverse country but is applicable to any ecosystem around the globe.</p>","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.70544","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145254974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 Scoping Review of Mosquito Vector Range Shifts: Widespread Expansions and Evidence Gaps in Climate Attribution","authors":"Kelsey Lyberger,&nbsp;Anna Rose Robinson,&nbsp;Lisa Couper,&nbsp;Isabel Delwel,&nbsp;Caroline Glidden,&nbsp;Crystal Qian,&nbsp;Aja Burslem,&nbsp;Faith Fernandez,&nbsp;Benjamen Gao,&nbsp;Gabriella Garcia,&nbsp;Julio Gomez,&nbsp;Kristen B. Greenland,&nbsp;Caspar Griffin,&nbsp;Stephanie Jackson,&nbsp;Annalisa King,&nbsp;Olivia Manes,&nbsp;Andrew Song,&nbsp;Edward Tran,&nbsp;Samantha Wilairat,&nbsp;Erin A. Mordecai","doi":"10.1111/gcb.70551","DOIUrl":"10.1111/gcb.70551","url":null,"abstract":"<div>\u0000 \u0000 <p>As global temperatures rise, concerns about shifting mosquito ranges—and accompanying changes in the transmission of malaria, dengue, and other diseases—are mounting. However, systematic evidence for climate-driven changes in mosquito ranges remains limited. We conducted a scoping review following PRISMA-ScR guidelines of studies documenting expansions or contractions in medically important mosquito species. In total, 178 studies on six continents identified range expansions in 118 mosquito species. While over a third of these studies cited warming as a driver, fewer than 10% performed statistical tests of the role of climate. Instead, most expansions were linked to human-aided dispersal (e.g., trade, travel), land-use changes, and urbanization. Although several studies reported poleward or upward expansions consistent with climate warming, none demonstrated warm-edge contractions driven by rising temperatures, which are theoretically predicted in some settings. Rather than expanding into newly suitable areas, many expansions appear to be filling preexisting thermally suitable habitats. Our findings highlight the need for long-term mosquito monitoring, rigorous climate-attribution methods, and better documentation of confounding factors like land-use change and vector control efforts to disentangle climate-driven changes from other anthropogenic factors.</p>\u0000 </div>","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145260779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Math-Corrected Enzyme Ratios: Descriptors of Allocation and Tools for Comparability—Not Proof of Limitation","authors":"Jérémy Puissant","doi":"10.1111/gcb.70517","DOIUrl":"10.1111/gcb.70517","url":null,"abstract":"&lt;p&gt;I thank Mori (&lt;span&gt;2025&lt;/span&gt;) for the thoughtful and constructive comment on my recent article (Puissant &lt;span&gt;2025&lt;/span&gt;). The article showed that ratios of log-transformed enzyme activities are unit-dependent and tend to converge toward 1, falsely suggesting a global C:N:P 1:1:1 pattern—a signal previously reported and widely interpreted as biological (Sinsabaugh et al. &lt;span&gt;2008&lt;/span&gt;, &lt;span&gt;2009&lt;/span&gt;), but arising here from mathematics rather than biology. The remedy is to compute direct ratios from raw activities (or vector metrics from raw shares), or to apply logs only after forming the ratio. This removes the mathematical artifact. By itself, however, it neither validates any threshold nor ensures that enzyme stoichiometry diagnoses nutrient limitation. On this broader point, I largely agree with Mori (&lt;span&gt;2025&lt;/span&gt;).&lt;/p&gt;&lt;p&gt;The broader debate over the usefulness of enzyme stoichiometry ratios is valuable. Several studies have raised critiques of inferring nutrient limitation from these ratios (e.g., Rosinger et al. &lt;span&gt;2019&lt;/span&gt;; Mori et al. &lt;span&gt;2023&lt;/span&gt;), while others report support under specific designs—particularly when ratios are interpreted temporally (weeks-scale integration) and corroborated with independent evidence (Moorhead et al. &lt;span&gt;2023&lt;/span&gt;; Kunito et al. &lt;span&gt;2024&lt;/span&gt;). As noted by Mori (&lt;span&gt;2025&lt;/span&gt;), ecoenzymatic theory still lacks comprehensive validation, and multiple arguments (e.g., terminal-step control, multiple enzymes per nutrient, lack of uniform responses to nutrient additions) urge caution.&lt;/p&gt;&lt;p&gt;\u0000 &lt;b&gt;Why enzyme ratios still matter—and why fixing the math is important?&lt;/b&gt;\u0000 &lt;/p&gt;&lt;p&gt;Measured activities are highly sensitive to assay conditions—substrate identity and concentration, pH, ionic strength, temperature, dilution, incubation time—yielding substantial between-lab and protocol variance for the same nominal enzyme (Nannipieri et al. &lt;span&gt;2018&lt;/span&gt;; Greenfield et al. &lt;span&gt;2021&lt;/span&gt;). When multiple enzymes are assayed under the same conditions within a study, many multiplicative scale factors act jointly; expressing activity as ratios (proportions)—i.e., ecoenzymatic ratios—helps cancel shared effects and improves within-study comparability, analogous to housekeeping-gene normalization in omics or intensity scaling in spectroscopy. Very extreme, distribution-incoherent ratios can also flag potential assay inconsistencies.&lt;/p&gt;&lt;p&gt;Ecoenzymatic ratios index extracellular enzyme production as an investment in acquiring specific substrates, which can decouple from instantaneous nutrient limitation under stress or constraint. Fundamental knowledge of soil enzyme regulation remains limited: alkaline phosphatases are classically induced under phosphate deprivation, whereas β-glucosidase and leucine aminopeptidase often show substrate-induced expression superimposed on variable constitutive baselines, with carbon- and nitrogen-catabolite effects that diff","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.70517","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145260784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Boreal Rivers as Sources of Terpenoid Emissions","authors":"Wasi Hashmi,&nbsp;Huizhong Zhang-Turpeinen,&nbsp;Lukas Kohl,&nbsp;Anne Kuningas,&nbsp;Carlos Palacin-Lizarbe,&nbsp;Xudan Zhu,&nbsp;Niko Kinnunen,&nbsp;Maija E. Marushchak,&nbsp;Janne Rinne,&nbsp;Anne Ojala,&nbsp;Frank Berninger,&nbsp;Jukka Pumpanen","doi":"10.1111/gcb.70540","DOIUrl":"10.1111/gcb.70540","url":null,"abstract":"<p>Streams and rivers are biogeochemical hotspots that contribute substantially to inland water CO₂ emissions. However, their role as sources of biogenic volatile organic compounds (BVOCs) remains poorly understood. We quantified terpenoid emissions from two boreal rivers in peatland and upland mineral soil catchments in Finnish Lapland based on monthly observations over two growing seasons. Both rivers were significant sources of terpenoid emissions, with predicted mean annual emissions of monoterpenes and sesquiterpenes around 4.9 ± 2.8 and 1.2 ± 0.8 mg m⁻² year⁻¹, respectively. The emissions were comparable to those from the boreal forest floor and other ecosystems, and they varied seasonally. The emission composition of the clear water river exhibited unclear seasonal variability and a greater diversity of compounds, while emissions of α-pinene and p-cymene showed distinct temporal trends in the brown water river. Dissolved organic carbon concentrations, SUVA₂₅₄, and air temperature were the main drivers of seasonal variation in emissions. Our study revealed that boreal lotic ecosystems are a significant source of terpenoid emissions, which should be considered in the estimations of global ecosystem BVOC emissions.</p>","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.70540","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145254657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"The Problem Is Not How We Calculate Enzyme Stoichiometry Threshold—It Is That We Calculate It","authors":"Taiki Mori","doi":"10.1111/gcb.70519","DOIUrl":"10.1111/gcb.70519","url":null,"abstract":"&lt;p&gt;A recent paper by Puissant (&lt;span&gt;2025&lt;/span&gt;) appropriately raised concerns about the use of log-transformed data in determining enzymatic stoichiometry thresholds—an important and valid critique. However, this discussion gives the misleading impression that, if the thresholds are calculated without log-transformation, they would function accurately. In reality, the more fundamental issue lies in the validity of calculating thresholds based on enzyme data itself. Here, I first address the conceptual issues associated with calculating thresholds from regressions of enzyme activity data—even when the log-transformation problem is resolved. Furthermore, while Puissant (&lt;span&gt;2025&lt;/span&gt;) suggests that addressing this issue would enable enzyme ratio calculations or vector analyses to serve as indicators of microbial nutrient limitation, I respectfully disagree with this conclusion. This is because multiple studies have shown that enzyme stoichiometry fails to reliably reflect nutrient limitation, and importantly, the enzyme stoichiometry framework has never been empirically validated.&lt;/p&gt;&lt;p&gt;Thresholds for carbon (C), nitrogen (N), and phosphorus (P) limitations were calculated using regression analyses of enzyme activity data measured under natural conditions. These analyses included: β-1,4-glucosidase (BG) versus N-acetylglucosaminidase (NAG) for C versus N limitation; BG versus acid or alkaline phosphatase (i.e., phosphomonoesterase, AP) for C versus P limitation; and NAG versus AP for N versus P limitation (Sinsabaugh et al. &lt;span&gt;2009&lt;/span&gt;). This approach assumes that the enzyme activities used to establish the thresholds represent either conditions of no nutrient limitation or equal limitation by all nutrients. Based on this assumption, deviations from these thresholds can be interpreted as indicators of C, N, or P limitation. However, this assumption lacks theoretical justification (Mori et al. &lt;span&gt;2023&lt;/span&gt;; Cui et al. &lt;span&gt;2024&lt;/span&gt;). Why should natural conditions be free from nutrient limitation? In fact, ecological understanding suggests that microbial activity is often constrained by one or more limiting nutrients (Kaspari et al. &lt;span&gt;2008&lt;/span&gt;). Furthermore, this underlying assumption—that typical or average natural conditions are nutrient-unlimited—is directly contradicted by how the thresholds are applied thereafter. In the application phase, the same type of enzyme data is used to test for nutrient limitations, based on the assumption that a specific nutrient is limiting. Consequently, the construction and application of the thresholds rest on fundamentally contradictory assumptions, leading to a methodological inconsistency.&lt;/p&gt;&lt;p&gt;Puissant (&lt;span&gt;2025&lt;/span&gt;) suggested that enzymatic stoichiometry and vector analysis remain valid methods, provided that enzyme activity ratios are calculated without prior log transformation. However, I respectfully disagree with this conclusion. It is important to underscore that both ap","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.70519","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145260780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 and Reduced Rainfall Alter Fungal Necromass Decomposition Rates and Associated Microbial Community Composition and Functioning at a Temperate–Boreal Forest Ecotone","authors":"Anahi Cantoran,&nbsp;François Maillard,&nbsp;Raimundo Bermudez,&nbsp;Artur Stefanski,&nbsp;Peter B. Reich,&nbsp;Peter G. Kennedy","doi":"10.1111/gcb.70536","DOIUrl":"10.1111/gcb.70536","url":null,"abstract":"<p>Changes in temperature and rainfall associated with altered climatic conditions are likely to significantly alter rates of soil organic matter decomposition. To determine how the combined effects of warming and drought impact the decomposition of fungal necromass, a large and fast-cycling portion of the global soil organic carbon (C) pool, we incubated <i>Hyaloscypha bicolor</i> necromass under both ambient and altered conditions (+3.3°C air and soil warming and ~40% reduced rainfall) at the B4Warmed experiment in Minnesota, USA. We conducted two multi-week incubations, one assessing mass loss and microbial community composition on decaying necromass after 1, 2, 7, and 14 weeks and the second characterizing the substrate utilization capacities of necromass-associated microbial communities after Weeks 1 and 7. Warming and reduced rainfall accelerated the initial rate of necromass decay by ~20%, yet slowed overall mass loss by ~6% at the end of the 14-week incubation. These different rates of decay over time paralleled shifting abiotic conditions, with altered plots experiencing warmer and relatively moist conditions early, but hotter and drier conditions later. The microbial community composition also varied by treatment and time, with warming and reduced rainfall stimulating fast-growing fungi as well as fungal relative to bacterial growth overall. Additionally, the functional capacity of the microbial community also changed over time, having a higher metabolic capability to utilize C and N substrates in the altered plots early in decomposition but a lower capability later in decay. Collectively, our findings highlight a dynamic, stage-dependent response of fungal necromass decomposition to altered climate regimes. By linking these decay dynamics to shifts in environmental conditions as well as microbial community composition and function, our study highlights the critical roles of both abiotic and biotic changes in mediating decomposition responses to climate change.</p>","PeriodicalId":175,"journal":{"name":"Global Change Biology","volume":"31 10","pages":""},"PeriodicalIF":12.0,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.70536","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145246665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}