Pub Date : 2025-02-13DOI: 10.1016/j.soilbio.2025.109747
Hannu Fritze , Jyrki Jauhiainen , Arta Bārdule , Aldis Butlers , Dovilė Čiuldienė , Muhammad Kamil-Sardar , Ain Kull , Raija Laiho , Andis Lazdiņš , Valters Samariks , Thomas Schindler , Kaido Soosaar , Egidijus Vigricas , Krista Peltoniemi
Soil trenching is a generally applied method used to differentiate heterotrophic respiration (RHET) from total respiration in soil CO2 flux data collection. However, the soil microbial community composition may change due to trenching and estimates of the impacts of any human-induced disturbance on RHET might be inflated if the microbial community involved was not the same as in the ambient untrenched environment. Here, we report that the bacterial and fungal community, as measured by amplicon sequencing, of 30 different research sites in peatland forests was mostly alike in trenched and untrenched plots still four years after trenching. Soil trenching thus seems to be a feasible method to study the RHET from peatland forest soils from the overall microbial community composition point of view as no major changes were observed.
{"title":"Soil trenching – are microbial communities alike in experimental peatland plots measuring total and heterotrophic respiration?","authors":"Hannu Fritze , Jyrki Jauhiainen , Arta Bārdule , Aldis Butlers , Dovilė Čiuldienė , Muhammad Kamil-Sardar , Ain Kull , Raija Laiho , Andis Lazdiņš , Valters Samariks , Thomas Schindler , Kaido Soosaar , Egidijus Vigricas , Krista Peltoniemi","doi":"10.1016/j.soilbio.2025.109747","DOIUrl":"10.1016/j.soilbio.2025.109747","url":null,"abstract":"<div><div>Soil trenching is a generally applied method used to differentiate heterotrophic respiration (R<sub>HET</sub>) from total respiration in soil CO<sub>2</sub> flux data collection. However, the soil microbial community composition may change due to trenching and estimates of the impacts of any human-induced disturbance on R<sub>HET</sub> might be inflated if the microbial community involved was not the same as in the ambient untrenched environment. Here, we report that the bacterial and fungal community, as measured by amplicon sequencing, of 30 different research sites in peatland forests was mostly alike in trenched and untrenched plots still four years after trenching. Soil trenching thus seems to be a feasible method to study the R<sub>HET</sub> from peatland forest soils from the overall microbial community composition point of view as no major changes were observed.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"203 ","pages":"Article 109747"},"PeriodicalIF":9.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-13DOI: 10.1016/j.soilbio.2025.109746
Andi Li , Peter Meidl , Senhao Wang , Bo Tang , Matthias C. Rillig , Guangcan Yu , Jing Chen , Rongzhen Liu , Zhiyang Lie , Anchi Wu , Lili Rong , Cheng Peng , Zhanfeng Liu , Wei Zhang , Xiankai Lu , Juxiu Liu , Qing Ye , Jiangming Mo , Mianhai Zheng
Knowledge about arbuscular mycorrhizal fungi (AMF) is crucial for understanding nutrient limitations on primary productivity and soil organic carbon (C) storage in terrestrial ecosystems. Both theoretical models and empirical evidence hold that nitrogen (N) addition in phosphorus-limited ecosystems can either increase or decrease AMF diversity and abundance. However, many of these studies involved high-level N additions, which do not reflect realistic levels of atmospheric N deposition, thus leading to biased estimations of AMF and their role in the soil C stock. Here, we assessed AMF diversity and abundance under N addition using data from five tropical forests, ranging from 88%, 31%, and 25% arbuscular mycorrhizal tree dominance to dual-mycorrhizal tree dominance, and combined it with a global synthesis of tropical/subtropical forests. Our field study showed that N addition based on realistic N deposition (≤50 kg N ha−1 yr−1, comparable to the actual rate of atmospheric N deposition in the studied sites) caused little change in AMF abundance and diversity, as confirmed by our meta-analysis. The responses of AMF abundance to N addition did not differ significantly across forests with varying mycorrhizal dominance. However, high-level N addition (>50 kg N ha−1 yr−1) from a global dataset reduced AMF abundance and diversity. AMF responses were correlated with plant C, soil nutrient availability, and/or pH. Our findings further indicate that current atmospheric N deposition is unlikely to enhance soil C content via AMF. Given that N deposition has been stable or even declined in major global economies, we propose that previous studies may have overestimated AMF responses to atmospheric N deposition, which neither increased nor reduced AMF abundance and diversity as previously thought.
{"title":"Atmospheric nitrogen deposition has minor impacts on the abundance and diversity of arbuscular mycorrhizal fungi and their contribution to soil carbon stock in tropical forests","authors":"Andi Li , Peter Meidl , Senhao Wang , Bo Tang , Matthias C. Rillig , Guangcan Yu , Jing Chen , Rongzhen Liu , Zhiyang Lie , Anchi Wu , Lili Rong , Cheng Peng , Zhanfeng Liu , Wei Zhang , Xiankai Lu , Juxiu Liu , Qing Ye , Jiangming Mo , Mianhai Zheng","doi":"10.1016/j.soilbio.2025.109746","DOIUrl":"10.1016/j.soilbio.2025.109746","url":null,"abstract":"<div><div>Knowledge about arbuscular mycorrhizal fungi (AMF) is crucial for understanding nutrient limitations on primary productivity and soil organic carbon (C) storage in terrestrial ecosystems. Both theoretical models and empirical evidence hold that nitrogen (N) addition in phosphorus-limited ecosystems can either increase or decrease AMF diversity and abundance. However, many of these studies involved high-level N additions, which do not reflect realistic levels of atmospheric N deposition, thus leading to biased estimations of AMF and their role in the soil C stock. Here, we assessed AMF diversity and abundance under N addition using data from five tropical forests, ranging from 88%, 31%, and 25% arbuscular mycorrhizal tree dominance to dual-mycorrhizal tree dominance, and combined it with a global synthesis of tropical/subtropical forests. Our field study showed that N addition based on realistic N deposition (≤50 kg N ha<sup>−1</sup> yr<sup>−1</sup>, comparable to the actual rate of atmospheric N deposition in the studied sites) caused little change in AMF abundance and diversity, as confirmed by our meta-analysis. The responses of AMF abundance to N addition did not differ significantly across forests with varying mycorrhizal dominance. However, high-level N addition (>50 kg N ha<sup>−1</sup> yr<sup>−1</sup>) from a global dataset reduced AMF abundance and diversity. AMF responses were correlated with plant C, soil nutrient availability, and/or pH. Our findings further indicate that current atmospheric N deposition is unlikely to enhance soil C content via AMF. Given that N deposition has been stable or even declined in major global economies, we propose that previous studies may have overestimated AMF responses to atmospheric N deposition, which neither increased nor reduced AMF abundance and diversity as previously thought.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"204 ","pages":"Article 109746"},"PeriodicalIF":9.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401208","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}
Pub Date : 2025-02-12DOI: 10.1016/j.soilbio.2025.109745
Jianqiu Zheng , Timothy D. Scheibe , Melanie A. Mayes , Michael N. Weintraub , J. Patrick Megonigal , Vanessa L. Bailey
Soil salinization, exacerbated by climate change, poses a global threat to coastal ecosystems and soil function. Salinity affects soil carbon cycling by directly impacting microbial activity and indirectly altering soil physicochemical properties. Current models inadequately represent these complexities, relying on linear reduction functions that overlook specific physicochemical changes induced by salinity. AquaMEND addresses this gap by integrating microbial-explicit carbon decomposition modeling with advanced geochemical processes. Through the incorporation of equilibrium chemistry via PHREEQC, AquaMEND accurately predicts soil chemistry responses to salinization and enables detailed simulations on how salinity impacts microbial processes. To represent microbial responses to salinity, we developed salt-sensitive and slat-resistant response functions, with microbial activity inhibited by 50% at 4 ppt and 55 ppt, respectively. While the choice of salinity response functions influences model outcomes, simulations revealed that respiration responses to salinization varied depend on the underlying microbial mechanisms. Increased microbial mortality and impaired extracellular enzyme activity led to decreased respiration, while reduced carbon use efficiency could enhance respiration unless substrate uptake was also inhibited by high salinity. These microbial processes interact in a coordinated manner with multiple abiotic factors, collectively determining both the direction and magnitude of soil carbon responses. These findings highlight the need for novel experiments to disentangle the complex interactions governing microbial and geochemical responses to salinity. AquaMEND's capability to model such interactions offers a versatile tool for studying and predicting the effects of soil salinization on belowground carbon cycling.
{"title":"AquaMEND: Reconciling multiple impacts of salinization on soil carbon biogeochemistry","authors":"Jianqiu Zheng , Timothy D. Scheibe , Melanie A. Mayes , Michael N. Weintraub , J. Patrick Megonigal , Vanessa L. Bailey","doi":"10.1016/j.soilbio.2025.109745","DOIUrl":"10.1016/j.soilbio.2025.109745","url":null,"abstract":"<div><div>Soil salinization, exacerbated by climate change, poses a global threat to coastal ecosystems and soil function. Salinity affects soil carbon cycling by directly impacting microbial activity and indirectly altering soil physicochemical properties. Current models inadequately represent these complexities, relying on linear reduction functions that overlook specific physicochemical changes induced by salinity. AquaMEND addresses this gap by integrating microbial-explicit carbon decomposition modeling with advanced geochemical processes. Through the incorporation of equilibrium chemistry via PHREEQC, AquaMEND accurately predicts soil chemistry responses to salinization and enables detailed simulations on how salinity impacts microbial processes. To represent microbial responses to salinity, we developed salt-sensitive and slat-resistant response functions, with microbial activity inhibited by 50% at 4 ppt and 55 ppt, respectively. While the choice of salinity response functions influences model outcomes, simulations revealed that respiration responses to salinization varied depend on the underlying microbial mechanisms. Increased microbial mortality and impaired extracellular enzyme activity led to decreased respiration, while reduced carbon use efficiency could enhance respiration unless substrate uptake was also inhibited by high salinity. These microbial processes interact in a coordinated manner with multiple abiotic factors, collectively determining both the direction and magnitude of soil carbon responses. These findings highlight the need for novel experiments to disentangle the complex interactions governing microbial and geochemical responses to salinity. AquaMEND's capability to model such interactions offers a versatile tool for studying and predicting the effects of soil salinization on belowground carbon cycling.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"203 ","pages":"Article 109745"},"PeriodicalIF":9.8,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393921","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}
Pub Date : 2025-02-11DOI: 10.1016/j.soilbio.2025.109741
Samuel E. Barnett , Ashley Shade
Viruses are important components of the soil microbiome, influencing microbial population dynamics and the functions of their hosts. However, the relationships and feedbacks between virus dynamics, microbial host dynamics, and environmental disturbance are not understood. Centralia, PA, USA, is the site of an underground coal seam fire that has been burning for over 60 years. As the fire moves along the coal seam, previously heated soils cool to ambient temperature, creating a gradient of heat disturbance intensity and recovery. We examined annual soil viral population dynamics over seven consecutive years in Centralia using untargeted metagenome sequencing. Viral communities changed over time and were distinct between fire-affected and reference sites. Dissimilarity in viral communities was greater across sites (space) than within a site across years (time), and cumulative viral diversity more rapidly stabilized within a site across years than within a year across sites. There also were changes in number of CRISPR arrays per genome as soils cooled, corresponding to shifts in viral diversity. Finally, there were also differences in viral-encoded auxiliary metabolic genes between fire-affected and reference sites. Thus, despite high site-to-site soil viral diversity, there was surprising viral community consistency within a site over the years and shifting host-viral interactions in soils recovering from disturbance. Overall, this work provides insights into the interannual dynamics of soil viruses and their host communities, as well as how they collectively respond to long-term warming.
{"title":"Soil viral community dynamics over seven years of heat disturbance: Spatial variation exceeds temporal in annually sampled soils","authors":"Samuel E. Barnett , Ashley Shade","doi":"10.1016/j.soilbio.2025.109741","DOIUrl":"10.1016/j.soilbio.2025.109741","url":null,"abstract":"<div><div>Viruses are important components of the soil microbiome, influencing microbial population dynamics and the functions of their hosts. However, the relationships and feedbacks between virus dynamics, microbial host dynamics, and environmental disturbance are not understood. Centralia, PA, USA, is the site of an underground coal seam fire that has been burning for over 60 years. As the fire moves along the coal seam, previously heated soils cool to ambient temperature, creating a gradient of heat disturbance intensity and recovery. We examined annual soil viral population dynamics over seven consecutive years in Centralia using untargeted metagenome sequencing. Viral communities changed over time and were distinct between fire-affected and reference sites. Dissimilarity in viral communities was greater across sites (space) than within a site across years (time), and cumulative viral diversity more rapidly stabilized within a site across years than within a year across sites. There also were changes in number of CRISPR arrays per genome as soils cooled, corresponding to shifts in viral diversity. Finally, there were also differences in viral-encoded auxiliary metabolic genes between fire-affected and reference sites. Thus, despite high site-to-site soil viral diversity, there was surprising viral community consistency within a site over the years and shifting host-viral interactions in soils recovering from disturbance. Overall, this work provides insights into the interannual dynamics of soil viruses and their host communities, as well as how they collectively respond to long-term warming.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"203 ","pages":"Article 109741"},"PeriodicalIF":9.8,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143385132","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}
Pub Date : 2025-02-11DOI: 10.1016/j.soilbio.2025.109744
Marie-Louise Schärer , Lucia Fuchslueger , Alberto Canarini , Andreas Richter , Andreas Lüscher , Ansgar Kahmen
Grasslands often recover well from drought, with some even surpassing non-drought-stressed controls in productivity long after drought release. However, the mechanisms responsible for such post-drought productivity outperformance remain unclear. In this study we examine how rewetting after drought influences important short- and longer-term soil microbial processes (i.e. nitrogen mineralization, potential enzyme activities) and consequent plant nutrient availability and uptake. For this, a field experiment was set up where an established perennial ryegrass sward under different N-fertilization levels was subjected to either a 2-month experimental summer drought followed by rewetting or to rainfed control conditions.
Rewetting after drought led to an immediate pulse in gross N-mineralization and NH4-consumption rates. Both rates increased by >230% and >430% in formerly drought-stressed subplots compared to controls in plots not N-fertilized and N-fertilized during drought, respectively. Importantly, gross N mineralization rates correlated significantly with extractable soil organic carbon contents at the end of drought. Concurrently, drought and rewetting significantly increased NO3–N, P, K, S, Fe, Zn, and Mn availability during the 1st but not the 2nd month after rewetting, except for K. Aboveground productivity of perennial ryegrass responded positively to NO3–N availabilities during the 1st month after rewetting, leading to productivity outperformance of formerly drought-stressed plots compared to controls. These results suggest that short-term productivity outperformance of perennial grasslands in the 1st month after rewetting is driven by an increase in NO3–N availability caused by a rewetting-induced pulse in N-mineralization of organic substrates accumulated during drought. Although effects of drought and rewetting on nutrient availability were only observed in the 1st month after rewetting, grassland productivity outperformance persisted in the 2nd month after rewetting. This indicates that soil drought legacy increased plant nutrient uptake efficiency, explaining longer-term outperformance effects when effects of drought and rewetting on nutrient availability were no longer apparent.
{"title":"Post-drought organic carbon mineralization leads to high productivity and nutrient uptake efficiency of perennial grassland after rewetting","authors":"Marie-Louise Schärer , Lucia Fuchslueger , Alberto Canarini , Andreas Richter , Andreas Lüscher , Ansgar Kahmen","doi":"10.1016/j.soilbio.2025.109744","DOIUrl":"10.1016/j.soilbio.2025.109744","url":null,"abstract":"<div><div>Grasslands often recover well from drought, with some even surpassing non-drought-stressed controls in productivity long after drought release. However, the mechanisms responsible for such post-drought productivity outperformance remain unclear. In this study we examine how rewetting after drought influences important short- and longer-term soil microbial processes (i.e. nitrogen mineralization, potential enzyme activities) and consequent plant nutrient availability and uptake. For this, a field experiment was set up where an established perennial ryegrass sward under different N-fertilization levels was subjected to either a 2-month experimental summer drought followed by rewetting or to rainfed control conditions.</div><div>Rewetting after drought led to an immediate pulse in gross N-mineralization and NH<sub>4</sub>-consumption rates. Both rates increased by >230% and >430% in formerly drought-stressed subplots compared to controls in plots not N-fertilized and N-fertilized during drought, respectively. Importantly, gross N mineralization rates correlated significantly with extractable soil organic carbon contents at the end of drought. Concurrently, drought and rewetting significantly increased NO<sub>3</sub>–N, P, K, S, Fe, Zn, and Mn availability during the 1st but not the 2nd month after rewetting, except for K. Aboveground productivity of perennial ryegrass responded positively to NO<sub>3</sub>–N availabilities during the 1st month after rewetting, leading to productivity outperformance of formerly drought-stressed plots compared to controls. These results suggest that short-term productivity outperformance of perennial grasslands in the 1st month after rewetting is driven by an increase in NO<sub>3</sub>–N availability caused by a rewetting-induced pulse in N-mineralization of organic substrates accumulated during drought. Although effects of drought and rewetting on nutrient availability were only observed in the 1st month after rewetting, grassland productivity outperformance persisted in the 2nd month after rewetting. This indicates that soil drought legacy increased plant nutrient uptake efficiency, explaining longer-term outperformance effects when effects of drought and rewetting on nutrient availability were no longer apparent.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"204 ","pages":"Article 109744"},"PeriodicalIF":9.8,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143385108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-10DOI: 10.1016/j.soilbio.2025.109743
Yao Li , Kate Buckeridge , Baorong Wang , Qian Huang , Chunhui Liu , Yuanjia Chen , Alberto Vinicius S. Rocha , Shaoshan An
Photosynthetic carbon (C) has a pivotal role in the C cycle of the plant-soil system, contributing significantly to soil organic C (SOC) accrual. Grassland soils have a large capacity to store organic C and grazing is an important factor influencing the C cycle, but few studies have quantitatively how grazing exclusion affects the transfer of photosynthetic C in a plant-soil-microbial system. We used in situ isotope pulse-chase methodology to study photosynthetic C allocation patterns in the grazed and grazing-excluded grassland soil of the Loess Plateau, China. Grazing exclusion increased the total assimilated 13C by 46% compared with the grazed grassland, but did not significantly change the 13C allocated to the aboveground (75%) and belowground (25%) plant biomass. The 13C transferred faster to soil via root exudates in the grazed soil with lower aboveground biomass, suggesting that removal of aboveground biomass by grazing animals influences the rate of C transfer. Most (79%) the SOC gained from grazing exclusion accumulated in the mineral associated organic C (MAOC) pool, which is a stronger predictor of SOC accrual than particulate organic C (POC). Grazing exclusion increased the transformation of POC to MAOC, mainly through the accumulation of microbial necromass. Grazing exclusion significantly reduced the G+/G- ratio and the fungal/bacteria ratio, indicating a shift in soil microbial community composition in favor of bacteria over fungi under grazing exclusion. Grazing exclusion increased the microbial biomass by 48% and significantly enhanced the capability of soil fungi and G- bacteria to access photosynthetic C. In summary, grazing exclusion increases the magnitude of C transfer from the atmosphere to soil microbial biomass, and the gradual conversion of POC to MAOC.
{"title":"Grazing exclusion enhanced the capability of soil microorganisms to access photosynthetic carbon in Loess Plateau grassland","authors":"Yao Li , Kate Buckeridge , Baorong Wang , Qian Huang , Chunhui Liu , Yuanjia Chen , Alberto Vinicius S. Rocha , Shaoshan An","doi":"10.1016/j.soilbio.2025.109743","DOIUrl":"10.1016/j.soilbio.2025.109743","url":null,"abstract":"<div><div>Photosynthetic carbon (C) has a pivotal role in the C cycle of the plant-soil system, contributing significantly to soil organic C (SOC) accrual. Grassland soils have a large capacity to store organic C and grazing is an important factor influencing the C cycle, but few studies have quantitatively how grazing exclusion affects the transfer of photosynthetic C in a plant-soil-microbial system. We used <em>in situ</em> isotope pulse-chase methodology to study photosynthetic C allocation patterns in the grazed and grazing-excluded grassland soil of the Loess Plateau, China. Grazing exclusion increased the total assimilated <sup>13</sup>C by 46% compared with the grazed grassland, but did not significantly change the <sup>13</sup>C allocated to the aboveground (75%) and belowground (25%) plant biomass. The <sup>13</sup>C transferred faster to soil via root exudates in the grazed soil with lower aboveground biomass, suggesting that removal of aboveground biomass by grazing animals influences the rate of C transfer. Most (79%) the SOC gained from grazing exclusion accumulated in the mineral associated organic C (MAOC) pool, which is a stronger predictor of SOC accrual than particulate organic C (POC). Grazing exclusion increased the transformation of POC to MAOC, mainly through the accumulation of microbial necromass. Grazing exclusion significantly reduced the G+/G- ratio and the fungal/bacteria ratio, indicating a shift in soil microbial community composition in favor of bacteria over fungi under grazing exclusion. Grazing exclusion increased the microbial biomass by 48% and significantly enhanced the capability of soil fungi and G- bacteria to access photosynthetic C. In summary, grazing exclusion increases the magnitude of C transfer from the atmosphere to soil microbial biomass, and the gradual conversion of POC to MAOC.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"203 ","pages":"Article 109743"},"PeriodicalIF":9.8,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143385110","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}
Pub Date : 2025-02-10DOI: 10.1016/j.soilbio.2025.109742
Shang Wang , Bahar S. Razavi , Sandra Spielvogel , Evgenia Blagodatskaya
Rising salinization of extended river-sides and estuary areas due to climate warming might alter microbial metabolic activity and cause unpredictable consequences for matter and energy turnover in soil. Therefore, we investigated the combined effects of salinization and warming on microbial activity and growth, examining CO₂ emissions (matter loss) and heat production (energy loss) during glucose metabolism. Soil from Elbe estuary was artificially salinized to medium (2.06 mS cm−1) and high (3.45 mS cm−1) levels, and ambient low salinity soil (0.93 mS cm−1) served as the control. We examined the influence of a comprehensive +2 °C climate warming (20 vs. 22 °C) on soil respiration (CO2 emission), heat release, enzyme kinetics (cellobiohydrolase, β-glucosidase, acid phosphomonoesterase and leucine-aminopeptidase) and microbial carbon use efficiency (CUE) across the microbial growth.
Increasing salinity did not impact respiration, heat release, microbial C and N content without glucose addition. However, activation of microorganisms with glucose brought force to the effect of salinity, and increasing salinity consistently retarded substrate uptake and growth. 2 °C warming affected substrate uptake and growth much more than increasing salinity. The calorespirometric ratio increased by 81–124% under high salinity compared to low salinity, with most of this increase occurring during the growth retardation stage. Enzyme activities increased by 68%–871% during the lag phase and remained relatively high throughout both the growth and retardation stages, regardless of salinity and temperature levels, suggesting the resistance of soil hydrolytic enzymes. The CUE gradually decreased and stabilized only at the very end of microbial growth, emphasizing the importance of considering the growth retardation for CUE estimation. Remarkably, disregarding the growth retardation stage resulted in a strong overestimation of the CUE accounting for 70%–98%. Our results highlight the importance of estimating the carbon budget of microbial growth by considering its dynamics when modeling carbon sequestration under global climate change.
{"title":"Energy and matter dynamics in an estuarine soil are more sensitive to warming than salinization","authors":"Shang Wang , Bahar S. Razavi , Sandra Spielvogel , Evgenia Blagodatskaya","doi":"10.1016/j.soilbio.2025.109742","DOIUrl":"10.1016/j.soilbio.2025.109742","url":null,"abstract":"<div><div>Rising salinization of extended river-sides and estuary areas due to climate warming might alter microbial metabolic activity and cause unpredictable consequences for matter and energy turnover in soil. Therefore, we investigated the combined effects of salinization and warming on microbial activity and growth, examining CO₂ emissions (matter loss) and heat production (energy loss) during glucose metabolism. Soil from Elbe estuary was artificially salinized to medium (2.06 mS cm<sup>−1</sup>) and high (3.45 mS cm<sup>−1</sup>) levels, and ambient low salinity soil (0.93 mS cm<sup>−1</sup>) served as the control. We examined the influence of a comprehensive +2 °C climate warming (20 vs. 22 °C) on soil respiration (CO<sub>2</sub> emission), heat release, enzyme kinetics (cellobiohydrolase, β-glucosidase, acid phosphomonoesterase and leucine-aminopeptidase) and microbial carbon use efficiency (CUE) across the microbial growth.</div><div>Increasing salinity did not impact respiration, heat release, microbial C and N content without glucose addition. However, activation of microorganisms with glucose brought force to the effect of salinity, and increasing salinity consistently retarded substrate uptake and growth. 2 °C warming affected substrate uptake and growth much more than increasing salinity. The calorespirometric ratio increased by 81–124% under high salinity compared to low salinity, with most of this increase occurring during the growth retardation stage. Enzyme activities increased by 68%–871% during the lag phase and remained relatively high throughout both the growth and retardation stages, regardless of salinity and temperature levels, suggesting the resistance of soil hydrolytic enzymes. The CUE gradually decreased and stabilized only at the very end of microbial growth, emphasizing the importance of considering the growth retardation for CUE estimation. Remarkably, disregarding the growth retardation stage resulted in a strong overestimation of the CUE accounting for 70%–98%. Our results highlight the importance of estimating the carbon budget of microbial growth by considering its dynamics when modeling carbon sequestration under global climate change.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"204 ","pages":"Article 109742"},"PeriodicalIF":9.8,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143385109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1016/j.soilbio.2025.109740
Alexander Konrad , Diana Hofmann , Jan Siemens , Kenton P. Stutz , Friederike Lang , Ines Mulder
Interactions between organic substances, minerals, and microorganisms are crucial for organic carbon (OC) stabilization in soil. We hypothesized that thresholds of sorption strength (described by the sorption coefficient of the Freundlich isotherms) and desorbability (i.e., the ratio of the amount desorbed to the amount sorbed) of organic monomers control the extent of their microbial processing.
Freundlich sorption isotherms and desorbability of uniformly 14C-labeled glucose, acetylglucosamine, phenylalanine, salicylic acid, and citric acid onto goethite, kaolinite, and illite were studied in batch experiments. Monomers adsorbed to minerals were mixed with loamy and sandy arable topsoil and incubated at 25 °C. Mineralization of mineral-adsorbed monomers was observed over three weeks, after which the assimilation into microbial biomass, and the 14C remaining in soil were quantified. Subsequently, the mineralization of incubated soils was observed for additional three weeks after glucose priming.
The adsorption of carboxylic acids onto minerals exceeded that of (amino) sugars and phenylalanine, with the overall highest amounts both adsorbed and retained after desorption with water for goethite. Assimilation of monomer 14C into microbial biomass and the microbial carbon use efficiency (CUE) of mineral-adsorbed monomers in both soils increased linearly with the monomer desorbability from mineral phases. Furthermore, the CUEs of monomers adsorbed to goethite were lower than those of the same monomers adsorbed to clay minerals. In terms of total amount of carbon retained in the soil, carboxylic acids adsorbed on goethite showed highest values, emphasizing the significance of oxides for the stabilization of OC within soils. Priming of incubated soil with non-labeled glucose caused an additional mineralization of monomer-C, with the priming effect decreasing from goethite to clay minerals.
We conclude that sorption strength and desorbability shape microbial utilization of mineral-bound organic compounds, but no universal thresholds determine bio-accessibility of sorbed organic compounds.
{"title":"Microbial carbon use efficiency of mineral-associated organic matter is related to its desorbability","authors":"Alexander Konrad , Diana Hofmann , Jan Siemens , Kenton P. Stutz , Friederike Lang , Ines Mulder","doi":"10.1016/j.soilbio.2025.109740","DOIUrl":"10.1016/j.soilbio.2025.109740","url":null,"abstract":"<div><div>Interactions between organic substances, minerals, and microorganisms are crucial for organic carbon (OC) stabilization in soil. We hypothesized that thresholds of sorption strength (described by the sorption coefficient of the Freundlich isotherms) and desorbability (i.e., the ratio of the amount desorbed to the amount sorbed) of organic monomers control the extent of their microbial processing.</div><div>Freundlich sorption isotherms and desorbability of uniformly <sup>14</sup>C-labeled glucose, acetylglucosamine, phenylalanine, salicylic acid, and citric acid onto goethite, kaolinite, and illite were studied in batch experiments. Monomers adsorbed to minerals were mixed with loamy and sandy arable topsoil and incubated at 25 °C. Mineralization of mineral-adsorbed monomers was observed over three weeks, after which the assimilation into microbial biomass, and the <sup>14</sup>C remaining in soil were quantified. Subsequently, the mineralization of incubated soils was observed for additional three weeks after glucose priming.</div><div>The adsorption of carboxylic acids onto minerals exceeded that of (amino) sugars and phenylalanine, with the overall highest amounts both adsorbed and retained after desorption with water for goethite. Assimilation of monomer <sup>14</sup>C into microbial biomass and the microbial carbon use efficiency (CUE) of mineral-adsorbed monomers in both soils increased linearly with the monomer desorbability from mineral phases. Furthermore, the CUEs of monomers adsorbed to goethite were lower than those of the same monomers adsorbed to clay minerals. In terms of total amount of carbon retained in the soil, carboxylic acids adsorbed on goethite showed highest values, emphasizing the significance of oxides for the stabilization of OC within soils. Priming of incubated soil with non-labeled glucose caused an additional mineralization of monomer-C, with the priming effect decreasing from goethite to clay minerals.</div><div>We conclude that sorption strength and desorbability shape microbial utilization of mineral-bound organic compounds, but no universal thresholds determine bio-accessibility of sorbed organic compounds.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"203 ","pages":"Article 109740"},"PeriodicalIF":9.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143371532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1016/j.soilbio.2025.109739
Issifou Amadou , Arnaud Mazurier , Laurent Caner , Yacouba Zi , Cornelia Rumpel , Nicolas Bottinelli
Earthworms significantly influence soil structure and associated ecosystem services, but the effect of different earthworm species and soil types on the physical organization of casts remains poorly understood. This study aims to shed light on the importance of earthworm species, soil type and their interactions in shaping cast microstructure. Using a microcosm experiment and X-ray microtomography image analysis, we examined the porosity and pore connectivity of casts produced by nine different temperate earthworm species in two contrasting soil types (Alluviosol and Cambisol). Our results showed that generally casts were characterized by lower overall porosity (reduced by 39–86% in Cambisol and 14–64% in Alluviosol) and pore connectivity (up to 76% lower in Cambisol) than control aggregates formed without earthworm activity, but they showed higher bioporosity (up to 50%). Both, earthworm species and soil type influenced pore properties, and the interaction of both explained most of the variability. In addition, we found no clear link between ecological categories of earthworms and the cast pore characteristics, highlighting the difficulty of generalizing species effects on cast microstructural properties. These results call for more nuanced approaches in future research to better predict earthworm effects on physical soil properties and resulting ecosystem services, considering both species-specific traits and their interactions with different soil environments.
{"title":"Interactions between earthworm species and soil type influence the porosity of earthworm casts","authors":"Issifou Amadou , Arnaud Mazurier , Laurent Caner , Yacouba Zi , Cornelia Rumpel , Nicolas Bottinelli","doi":"10.1016/j.soilbio.2025.109739","DOIUrl":"10.1016/j.soilbio.2025.109739","url":null,"abstract":"<div><div>Earthworms significantly influence soil structure and associated ecosystem services, but the effect of different earthworm species and soil types on the physical organization of casts remains poorly understood. This study aims to shed light on the importance of earthworm species, soil type and their interactions in shaping cast microstructure. Using a microcosm experiment and X-ray microtomography image analysis, we examined the porosity and pore connectivity of casts produced by nine different temperate earthworm species in two contrasting soil types (Alluviosol and Cambisol). Our results showed that generally casts were characterized by lower overall porosity (reduced by 39–86% in Cambisol and 14–64% in Alluviosol) and pore connectivity (up to 76% lower in Cambisol) than control aggregates formed without earthworm activity, but they showed higher bioporosity (up to 50%). Both, earthworm species and soil type influenced pore properties, and the interaction of both explained most of the variability. In addition, we found no clear link between ecological categories of earthworms and the cast pore characteristics, highlighting the difficulty of generalizing species effects on cast microstructural properties. These results call for more nuanced approaches in future research to better predict earthworm effects on physical soil properties and resulting ecosystem services, considering both species-specific traits and their interactions with different soil environments.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"203 ","pages":"Article 109739"},"PeriodicalIF":9.8,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143257888","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}
Pub Date : 2025-02-05DOI: 10.1016/j.soilbio.2025.109738
Julia Wiesenbauer , Stefan Gorka , Kian Jenab , Raphael Schuster , Naresh Kumar , Cornelia Rottensteiner , Alexander König , Stephan Kraemer , Erich Inselsbacher , Christina Kaiser
Sugars and organic acids, primary components in plant root exudates, are thought to enhance microbial decomposition of organic matter in the rhizosphere. However, their specific impacts on microbial activity and nutrient mobilisation remain poorly understood. Here, we simulated passive root exudation to investigate the distinct effects of sugars and organic acids on microbial metabolism in the rhizosphere. We released 13C-labelled sugars and/or organic acids via reverse microdialysis into intact meadow and forest soils over 6-h. We measured substrate-induced microbial respiration, soil organic matter mineralization, metabolite concentrations, and substrate incorporation into lipid-derived fatty acids. Our results reveal a pronounced microbial preference for organic acids over sugars, with organic acids being removed faster from the exudation spot and preferentially respired by microbes. Unlike sugars, organic acids increased concentrations of microbial metabolic byproducts and cations (K, Ca, Mg) near the exudation spot. Our results challenge the prevailing assumption that sugars are the most readily available and rapidly consumed substrates for soil microbes. Microbial preference for organic acids indicates a trade-off between rapid biomass growth and ATP yield. Our findings underscore the significant role of exudate composition in influencing microbial dynamics and nutrient availability, and emphasize the importance of biotic and abiotic feedback mechanisms in the rhizosphere in regulating root exudation.
{"title":"Preferential use of organic acids over sugars by soil microbes in simulated root exudation","authors":"Julia Wiesenbauer , Stefan Gorka , Kian Jenab , Raphael Schuster , Naresh Kumar , Cornelia Rottensteiner , Alexander König , Stephan Kraemer , Erich Inselsbacher , Christina Kaiser","doi":"10.1016/j.soilbio.2025.109738","DOIUrl":"10.1016/j.soilbio.2025.109738","url":null,"abstract":"<div><div>Sugars and organic acids, primary components in plant root exudates, are thought to enhance microbial decomposition of organic matter in the rhizosphere. However, their specific impacts on microbial activity and nutrient mobilisation remain poorly understood. Here, we simulated passive root exudation to investigate the distinct effects of sugars and organic acids on microbial metabolism in the rhizosphere. We released <sup>13</sup>C-labelled sugars and/or organic acids via reverse microdialysis into intact meadow and forest soils over 6-h. We measured substrate-induced microbial respiration, soil organic matter mineralization, metabolite concentrations, and substrate incorporation into lipid-derived fatty acids. Our results reveal a pronounced microbial preference for organic acids over sugars, with organic acids being removed faster from the exudation spot and preferentially respired by microbes. Unlike sugars, organic acids increased concentrations of microbial metabolic byproducts and cations (K, Ca, Mg) near the exudation spot. Our results challenge the prevailing assumption that sugars are the most readily available and rapidly consumed substrates for soil microbes. Microbial preference for organic acids indicates a trade-off between rapid biomass growth and ATP yield. Our findings underscore the significant role of exudate composition in influencing microbial dynamics and nutrient availability, and emphasize the importance of biotic and abiotic feedback mechanisms in the rhizosphere in regulating root exudation.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"203 ","pages":"Article 109738"},"PeriodicalIF":9.8,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143191739","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}
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