Soil Biology & Biochemistry最新文献

{"title":"Microbial mechanisms underlying differences of methane emissions between urban and rural wetlands","authors":"Yuwen Lin, Xinyu Yi, Chen Ning, Yong Li, Yinghe Peng, Shuguang Liu, Changhui Peng, Xiaoyong Chen, Shuailong Feng, Pengpeng Duan, Yan Liu, Juyang Liao","doi":"10.1016/j.soilbio.2025.109993","DOIUrl":"https://doi.org/10.1016/j.soilbio.2025.109993","url":null,"abstract":"Methane (CH₄) emissions differ between urban and rural wetlands, while the microbial mechanisms associated with these differences have not been clearly identified. Here, we characterized the CH₄-cycling microbial communities and their functional function metabolic pathways between urban and rural wetlands by using 16S rRNA amplicon sequencing, metagenomes and CH₄ flux measurements. Results showed that rural wetlands primarily utilized acetate/CO₂-dependent methanogenic pathway and complete carbon oxidation to CO₂ in methanotrophic pathway. Whereas, urban wetlands were dominated by the coenzyme M-dependent methanogenic pathway and trimethylamine catabolism, with methanotrophic pathway characterized by enhanced carbon assimilation capacity. In wetland water, while the abundances of methanogens in urban water were 5-fold lower than in rural water, urban water exhibited stronger microbial cooperation and higher metabolic flexibility, which were associated with an 85% higher water-atmosphere CH₄ flux compared to rural counterparts. In wetland soil, key environmental factors (e.g. higher pH and lower organic matter content compared to rural sites) shaped distinct microbial community structures and CH₄ metabolic traits. These differences were shown as higher functional gene diversity, more stable co-occurrence networks, and greater metabolic flexibility, which were linked to a 6-fold higher soil CH₄ emissions than in rural soil. This study describes the microbial mechanisms underlying CH₄ emission differences between urban and rural wetlands, providing insights into microbially mediated CH₄ cycling in urban wetland ecosystems.","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"97 1","pages":""},"PeriodicalIF":9.7,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bacterial necromass decomposition and priming effects in paddy soils depend on long-term fertilization","authors":"Qi Liu ,&nbsp;Zhenke Zhu ,&nbsp;Liang Wei ,&nbsp;Wenju Zhang ,&nbsp;Shuang Wang ,&nbsp;Hongzhao Yuan ,&nbsp;Jianping Chen ,&nbsp;Tida Ge ,&nbsp;Minggang Xu ,&nbsp;Yakov Kuzyakov","doi":"10.1016/j.soilbio.2025.109992","DOIUrl":"10.1016/j.soilbio.2025.109992","url":null,"abstract":"<div><div>Long-term fertilization alters nutrient availability and microbial community composition in soil, thereby modulating the decomposition of microbial necromass and its influence on soil organic carbon (SOC) turnover. However, the microbial taxa that drive necromass recycling and how their activity translates into positive or negative priming effects (PEs) on SOC mineralization in rice paddies remain unknown. We combined ¹³C isotope probing and high-throughput sequencing to investigate the microbial groups involved in necromass decomposition and their associated PEs on SOC mineralization in paddy soils subjected to 34 years of mineral fertilization or chicken manure application as compared to unfertilized control soil. Following the addition of ¹³C-labeled bacterial necromass, 50–60 % of the ¹³C was mineralized to CO₂ within 210 days, with fertilized soils releasing 15 % more ¹³C–CO₂ compared to unfertilized soils. Microbial uptake of ¹³C from necromass occurred sequentially: Gram-positive (Gram⁺) bacteria dominated initial incorporation (within 5 days), followed by uptake by Gram-negative (Gram⁻) bacteria and thereafter by actinomycetes and fungi after 40 days. In unfertilized carbon-limited soils, <em>K</em>-strategist taxa, such as Gram⁺ bacteria, <em>Gamma-proteobacteria</em>, <em>Patescibacteria</em>, and <em>Basidiomycota</em>, mined recalcitrant SOC to fulfill their nutrient demands, thus generating a strong positive PE. Conversely, in soils receiving combined mineral and organic inputs, <em>r</em>-strategist taxa, including Gram⁻ bacteria, <em>Alpha-proteobacteria</em>, and <em>Ascomycota</em>, preferentially decomposed newly formed microbial necromass rather than SOC, resulting in a negative PE and net SOC accumulation. These findings demonstrate that fertilization-driven shifts in microbial life-history strategies as well as SOC availability govern necromass turnover and its priming consequences, highlighting necromass recycling as a key lever to raise SOC stabilization. Thus, managing fertilizer regimes to favor targeted microbial guilds offers a promising pathway to increase carbon sequestration and sustain soil health in paddy ecosystems.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109992"},"PeriodicalIF":10.3,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precipitation rather than temperature dominates microbial necromass accumulation by regulating soil physicochemical properties in alpine wetlands","authors":"Xiongjie Sheng ,&nbsp;Juan Zhou ,&nbsp;Meng Lu ,&nbsp;Hui Jin ,&nbsp;Wenli Wang ,&nbsp;Zhiming Zhang ,&nbsp;Liding Chen ,&nbsp;Wenjun Liu ,&nbsp;Xun Wang ,&nbsp;Qiong La ,&nbsp;Jingxin Huang ,&nbsp;Zhiheng Ma ,&nbsp;Yuhan Gao ,&nbsp;Yuan Chi ,&nbsp;Xiaolin Dou","doi":"10.1016/j.soilbio.2025.109987","DOIUrl":"10.1016/j.soilbio.2025.109987","url":null,"abstract":"<div><div>Microbial necromass is a key component of stable soil organic carbon (C) and contributes substantially to long-term C sequestration, accounting for nearly half of soil C content in terrestrial ecosystems. However, both the contribution of microbial necromass to soil C in wetland soils and the environmental factors regulating the distribution of microbial residues remain poorly understood, especially in alpine regions. Here, we sampled 105 alpine wetlands across the Qinghai-Tibet Plateau to investigate the effects of climatic, soil, and plant factors on microbial-derived C. On average, microbial residues accounted for 17.7 % of soil organic C, with swamp wetlands exhibiting the highest microbial necromass C content but a relatively lower contribution to soil organic C than other wetland types. Fungal residues contributed more to soil C (11.6 %) than bacterial residues (6.1 %), reflecting the predominance of fungal-derived residues in soil C. Mean annual precipitation improved soil moisture and nutrient availability (e.g., soil organic C, N and ammonium-N) and alleviated salinity stress by reducing electrical conductivity, thereby favoring microbial activity and turnover, and ultimately enhancing microbial residue formation. Temperature and plant properties had relatively minor effects within the narrow temperature range (−5 to +5 °C) observed at most sites. Our findings highlight the pivotal role of precipitation in regulating soil physicochemical conditions and promoting microbial residue formation, suggesting that future changes in precipitation regimes may strongly influence residue dynamics and long-term C sequestration in alpine wetlands.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109987"},"PeriodicalIF":10.3,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145153874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biotic and abiotic factors controlling terpenoid exchange from soil of a mixed temperate forest ecosystem","authors":"Jürgen Kreuzwieser ,&nbsp;Hojin Lee ,&nbsp;Alina Köhler ,&nbsp;Andreas Christen ,&nbsp;Markus Sulzer ,&nbsp;Helmer Schack-Kirchner ,&nbsp;Julian Brzozon ,&nbsp;Friederike Lang ,&nbsp;L. Erik Daber ,&nbsp;Rahel Bechtold ,&nbsp;Christiane Werner","doi":"10.1016/j.soilbio.2025.109991","DOIUrl":"10.1016/j.soilbio.2025.109991","url":null,"abstract":"<div><div>The contribution of forest floors to the ecosystem budget of volatile terpenoids is still not fully understood. We performed seasonal measurements in a mixed temperate forest to elucidate the effects of tree species (Douglas fir vs. European beech) and abiotic drivers on soil-atmosphere terpenoid exchange. In addition, soil cores were studied under controlled conditions to characterize the effect of ambient air terpenoid concentrations on exchange rates of terpenoids and their enantiomers. Moreover, the role of litter layer and microbial activity on exchange of important terpenoids enantiomers was tested. Soil under Douglas fir emitted monoterpenes at rates up to 3 μg m⁻² h⁻¹, whereas soil under European beech released terpenes at much lower rates and occasionally even took up these volatiles. Exchange followed seasonal patterns with low fluxes during winter, increasing emissions during springtime and reduced exchange rates in summer. Flux rates weakly correlated with soil temperature, soil moisture and ambient terpenoid concentrations. In isolated soil cores emission of terpenoids was enantiomer specific, which was not observed for terpenoid uptake. Increasing ambient concentrations caused a switch from emission to an uptake of terpenoids at compound specific compensation points ranging between 10 and 250 ppt. More detailed analyses indicated that the litter layer and not the mineral soil is the main contributor for soil terpenoid exchange, and that microbial activity plays an important role for terpenoid uptake but not for emission. In conclusion, our results highlight a strong contribution of the forest floor to the ecosystem budget of terpenoids. For temperate forests tree-species and related litter determine terpenoid emission from the forest floor, whereas terpenoid uptake is driven by soil microbial activity. The balance of exchange is modulated by soil temperature and ambient terpenoid concentrations. It remains to be elucidated whether such relationships apply to forests in other biomes.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109991"},"PeriodicalIF":10.3,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Joint effects of predatory protists and predatory bacteria on driving the evolution of bacterial antibiotic resistance","authors":"Thi Bao-Anh Nguyen ,&nbsp;Kenneth Dumack ,&nbsp;Michael Bonkowski ,&nbsp;Qing-Lin Chen ,&nbsp;Tim Urich ,&nbsp;Verena Groß ,&nbsp;Ji-Zheng He ,&nbsp;Hang-Wei Hu","doi":"10.1016/j.soilbio.2025.109990","DOIUrl":"10.1016/j.soilbio.2025.109990","url":null,"abstract":"<div><div>Biological factors, especially predator-prey interactions, are crucial drivers of ecological processes. However, their roles in driving the evolution of antibiotic resistance, a global health concern, remain poorly understood in complex natural soil ecosystems. Predatory protists and predatory bacteria are primary bacterial predators, however, mechanisms underlying the influence of their predation on the richness and abundance of bacterial antibiotic resistance within a multitrophic soil ecosystem are still poorly known. Here, we assessed effects of soil predatory protists on predatory bacteria and antibiotic resistance genes (ARGs) across a gradient of protist concentrations under the control of bacteria's competitors – fungi. Our findings reveal that high-protist predation pressure significantly amplified the relative abundance of predatory bacteria <em>Streptomycetales</em> and <em>Myxococcales</em> between days 15 and 45 of the microcosm incubation. Aligning with a rising abundance of predatory bacteria and antibiotic-producing bacteria, the relative abundance and diversity of soil ARGs significantly increased under high protist concentrations, regardless of fungal effects. Many ARGs encoding key resistance mechanisms (antibiotic deactivation and efflux pumps) were enriched in response to predatory protists within complex inter-group interactions. Moreover, these enriched ARGs were strongly associated with both predatory bacteria and predatory protists. More profound effects of predatory protists on the predatory bacteria and soil ARGs were identified in the presence of fungi. Our study provides novel evidence about crucial effects of predatory protists on shaping the predatory bacterial community and driving bacterial antibiotic resistance under complex multitrophic interactions in a natural soil. These findings pave the way for future research aimed at mitigating this global health issue and uncovering other ecological processes.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109990"},"PeriodicalIF":10.3,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145134465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil biodiversity and ecosystem functions in grasslands: Is more always better?","authors":"Dajana Radujković ,&nbsp;Miguel Portillo-Estrada ,&nbsp;Björn Hendrickx ,&nbsp;Giandiego Campetella ,&nbsp;Willem-Jan Emsens ,&nbsp;Mária Höhn ,&nbsp;Gerald Jurasinski ,&nbsp;Stefano Chelli ,&nbsp;Tim Vochten ,&nbsp;Erik Verbruggen","doi":"10.1016/j.soilbio.2025.109988","DOIUrl":"10.1016/j.soilbio.2025.109988","url":null,"abstract":"<div><div>Given the biodiversity crisis, research on soil biodiversity and ecosystem functioning (BEF) has grown rapidly. While a positive BEF relationship is often reported, whether it holds across different soils with distinct soil and plant communities remains understudied. Here, we conducted a greenhouse experiment containing five experimental grassland systems representing different (semi)natural grasslands. Each grassland system contained four biodiversity levels established by sequential filtering of the field soil community by size, creating a gradient in their presence, richness and thus community completeness. We found that shoot biomass remained unaffected by treatments. However, consistent with expectations of a positive BEF relationship, nitrification potential and microbial nitrogen content generally increased with biodiversity increase, whereas the relative abundance of predatory/parasitic bacteria decreased. On the contrary, high soil biodiversity led to a decrease in plant nitrogen content and soil urea degradation potential, suggesting that soil biodiversity may influence competition for nitrogen between plants and microbes. Moreover, while microbial biomass carbon was promoted by soil biodiversity in relatively fertile grassland soils and root biomass was unaffected, they were both reduced in poorer soils. These findings highlight that soil biodiversity may promote certain grassland functions but suppress others and that the direction of these trade-offs may depend on the soil characteristics or the biotic community it harbours. The conservation and management of soil biodiversity thus need to be evaluated in the context of the functions that are to be maximised and the grassland soil context.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109988"},"PeriodicalIF":10.3,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145116176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regulation of straw-derived nitrogen dynamics by its quality: Implications for N2O mitigation","authors":"Xiu Liu ,&nbsp;Congyue Tou ,&nbsp;Sheng Tang ,&nbsp;Ji Chen ,&nbsp;Wolfgang Wanek ,&nbsp;David R. Chadwick ,&nbsp;Davey L. Jones ,&nbsp;Yongchao Liang ,&nbsp;Lianghuan Wu ,&nbsp;Qingxu Ma","doi":"10.1016/j.soilbio.2025.109989","DOIUrl":"10.1016/j.soilbio.2025.109989","url":null,"abstract":"<div><div>Straw incorporation improves soil fertility and regulates nitrogen (N) cycling, with straw quality serving as a key driver of N transformation. However, the mechanisms by which straw quality regulates straw-derived N dynamics remain unclear. Here, we used ¹⁵N-labeled maize straw with contrasting contents of carbon, N, phosphorus, lignin, hemicellulose, and cellulose to trace ¹⁵N incorporation into ¹⁵NH₄⁺, ¹⁵NO₃⁻, and ¹⁵N₂O during early (14-day) and late (84-day) incubation. On day 14, 3.3 %, 0.7 %, and 0.01 % of straw-derived ¹⁵N had been transformed into ¹⁵NH₄⁺, ¹⁵NO₃⁻, and ¹⁵N₂O, respectively. By day 84, ¹⁵NH₄⁺ declined to 2.1 %, whereas ¹⁵NO₃⁻ and ¹⁵N₂O increased to 1.1 % and 0.04 %, respectively, resulting in a cumulative loss of 0.1 %–0.3 % of straw-derived ¹⁵N as ¹⁵N₂O. During the early stage, decomposition of labile carbon fractions (hemicellulose and cellulose content) stimulated tyrosine aminopeptidase activity and the abundance of N-mineralizing genes, driving ¹⁵NH₄⁺ formation. However, strong microbial N demand, reflected by elevated NH₄⁺ assimilation and low nitrification gene abundance, promoted microbial immobilization and limited ¹⁵NO₃⁻ and ¹⁵N₂O production. In the late stage, the shift toward recalcitrant carbon reshaped microbial communities and increased α-diversity, thereby suppressing further N mineralization but enhancing nitrification of previously immobilized N via increased <em>amoA</em>, <em>amoB</em>, and <em>hao</em> gene abundances, leading to greater ¹⁵NO₃⁻ accumulation and ¹⁵N₂O emissions. Random forest analysis identified hemicellulose and cellulose content as the dominant regulators of straw N transformation, with higher hemicellulose content consistently associated with reduced ¹⁵N₂O emissions. These findings reveal temporal shifts in microbial N processing mediated by straw quality and suggest that optimizing straw C/N ratios, together with microbial inoculants or nitrification inhibitors, could improve synchronization of straw N release with crop demand while mitigating gaseous N losses.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109989"},"PeriodicalIF":10.3,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145116207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changed by fire: linking carbon and energy fluxes by microbial decomposition of soil organic matter after frequent forest burning events","authors":"Zhenhui Jiang ,&nbsp;Olga Ogneva ,&nbsp;Yakov Kuzyakov ,&nbsp;Chengrong Chen ,&nbsp;Maryam Esfandbod ,&nbsp;Mehran Rezaei Rashti ,&nbsp;Yongfu Li ,&nbsp;Anna Gunina","doi":"10.1016/j.soilbio.2025.109986","DOIUrl":"10.1016/j.soilbio.2025.109986","url":null,"abstract":"<div><div>Frequent burning by wildfires and its induced dry–wet cycles pose increasing threats to soil organic matter (SOM) stability. Yet, their interactive effects on microbially-driven decomposition and priming effects remain unclear from the combined perspectives of CO₂ emissions and energy (i.e., heat) release. The relationship between microbial substrate use efficiency (SUE) and the calorespirometric ratio (CR, heat-to-CO₂) remains unclear. Here, we investigated how long-term prescribed burning over 46 years, applied at two- (B2) and four-year (B4) intervals, interacts with dry–wet cycles (defined as cycles of soil drying and rewetting that reflect fire-induced moisture fluctuations) and influences SOM decomposition. Using the addition of ¹⁴C-labeled glucose coupled with calorespirometry, we tracked SOM-derived CO₂ and heat fluxes and quantified the priming effect during a 28-day microcosm experiment. B4 increased SOM-derived CO₂ efflux and heat release vs. unburned soils (NB), while B2 suppressed both. Dry–wet cycles increased SOM-derived CO₂ but reduced SUE, favoring respiration over biomass synthesis. B4 under wet conditions produced higher primed heat release than NB, which was linked to the use of a chemically complex substrates (indicated by elevated CR). The decoupled primed CO₂-heat indicated distinct thermodynamic pathways for carbon (C) and energy release. A positive CR–SUE correlation revealed a metabolic coordination between energy release and organic matter assimilation, suggesting that microbes allocate additional energy to sustain biomass growth even under elevated energetic costs. These findings demonstrate that low-frequency burning accelerated C loss via energy-intensive decomposition of SOM, while dry–wet cycles increased soil C vulnerability by uncoupling microbial growth and respiration. Integrating C and energy flux metrics provides novel insights into C resilience in soil under compounding climate disturbances, urging balanced fire management and C conservation in vulnerable ecosystems.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109986"},"PeriodicalIF":10.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145116177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chaparral wildfire shifts the functional potential for soil pyrogenic organic matter and nitrogen cycling","authors":"M. Fabiola Pulido Barriga ,&nbsp;Amelia Nelson Kuhn ,&nbsp;Peter M. Homyak ,&nbsp;Michael J. Wilkins ,&nbsp;Sydney I. Glassman","doi":"10.1016/j.soilbio.2025.109985","DOIUrl":"10.1016/j.soilbio.2025.109985","url":null,"abstract":"<div><div>Wildfires reshape soil microbiomes and chemistry, enhancing nitrogen availability and leaving behind pyrogenic organic matter (PyOM), a difficult to degrade carbon substrate potentially used by pyrophilous or “fire-loving” microbes. Understanding whether pyrophilous bacteria can metabolize post-fire resources is critical for predicting the fate of both carbon and nitrogen. We explored how secondary succession of pyrophilous bacteria align with changes in functional gene composition, particularly genes related to PyOM degradation and microbial nitrogen metabolism using shotgun metagenomics on 30 burned and unburned soils collected at 17, 25, 34, 131, and 376 days after a high-severity wildfire in a fire-adapted chaparral in Southern California. In burned soils, genes for PyOM degradation increased over time by 167% and for inorganic nitrogen cycling by 117%, while unburned soils showed no significant changes. Genes encoding catechol and protocatechuate, intermediates in the PyOM degradation pathway, indicate that the easier-to-degrade ortho-cleavage pathways consistently dominated the burned plots. These genes were often found alongside genes for nitrification and nitrogen retention, including assimilatory and dissimilatory nitrate reduction to ammonia (DNRA). We reconstructed 446 bacterial metagenome-assembled genomes (MAGs) and linked gene profiles to dominant taxa. Increases in genes associated with PyOM degradation and N cycling coincided with the dominance of pyrophilous <em>Massilia</em> and <em>Noviherbaspirillum</em>, which encoded distinct pathways for PyOM and inorganic N metabolism over time. Together, these findings reveal unrecognized functional shifts in bacterial communities over a high-resolution successional timeline, providing insights into the long-term impact of fire on microbial-mediated ecosystem processes that shape soil carbon and nitrogen dynamics.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109985"},"PeriodicalIF":10.3,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145083665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vegetation type and climate determine temperature thresholds of soil respiration across drylands","authors":"María Almagro ,&nbsp;Ana Rey ,&nbsp;Rosa M. Inclán ,&nbsp;Josep Barba ,&nbsp;Rodrigo Vargas ,&nbsp;Arnaud Carrara ,&nbsp;José M. Grünzweig ,&nbsp;Marcelo Sternberg ,&nbsp;Yiftach Talmon ,&nbsp;Rebecca L. McCulley ,&nbsp;Sara Marañón-Jiménez ,&nbsp;Penélope Serrano-Ortiz ,&nbsp;Javier Martínez-López ,&nbsp;Carme Estruch ,&nbsp;Gabriele Guidolotti ,&nbsp;Chao-Ting Chang ,&nbsp;Joan Llovet ,&nbsp;Mauro Lo Cascio ,&nbsp;Jorge F. Perez-Quezada ,&nbsp;Alexandra C. Correia ,&nbsp;Jorge Curiel Yuste","doi":"10.1016/j.soilbio.2025.109984","DOIUrl":"10.1016/j.soilbio.2025.109984","url":null,"abstract":"<div><div>Soil respiration (SR) is a key component of terrestrial carbon-climate feedbacks, yet its seasonal dynamics in drylands remain poorly understood. In mesic ecosystems, SR is primarily temperature driven, whereas in drylands it shifts seasonally from temperature to moisture control as autotrophic and heterotrophic respiration become water limited during dry periods. Identifying the soil temperature at which SR transitions from temperature to moisture limitation is therefore essential for predicting SR under climate change. We examined temperature and moisture response functions of SR across forests, shrublands, and grasslands in arid and semi-arid regions to determine the soil temperature threshold of SR (STT_SR) and its drivers. Across sites, SR was positively correlated with mean annual precipitation, soil moisture, and soil organic carbon, while negatively correlated with soil temperature. The significant variability in the temperature thresholds of SR (STT_SR) that was observed between sites (17.9 °C ± 5.3 °C; mean ± SD) was best explained by the mean annual temperature (MAT) at the site. Sites with higher air temperatures exhibited higher STT_SR, suggesting that the compartments and metabolic processes involved in SR are adapted to local temperatures. This observed SR adaptation occurred at two different scales. Besides STT_SR were positively correlated with MAT within each vegetation type, STT_SR were systematically higher under short-stature vegetation types (grasslands and shrublands) compared to high-stature vegetation types (forests), suggesting that grasses and shrubs have developed the evolutionary capacity to push the STT_SR to warmer temperatures and hence withstand better drought stress than trees. Our findings suggest that: (1) process-based models assuming simple linear or exponential SR-temperature relationships overestimate SR in water-limited ecosystems; and (2) projected warming and increasing water scarcity, together with shifts in vegetation dominance, may strongly modify the temperature sensitivity of SR.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109984"},"PeriodicalIF":10.3,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145083666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}