Soil Biology & Biochemistry最新文献

{"title":"Irrigation alters biogeochemical processes to increase both inorganic and organic carbon in arid-calcic cropland soils","authors":"K.R. Ball ,&nbsp;A.A. Malik ,&nbsp;C. Muscarella ,&nbsp;J.C. Blankinship","doi":"10.1016/j.soilbio.2023.109189","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109189","url":null,"abstract":"<div><p>Irrigation in arid croplands is necessary to sustain crop growth, but with increasing water scarcity and population growth in drylands, irrigation systems may need to shift from flooding to dripping techniques to cope with increased water demand. Therefore, it is important to understand how irrigation drives organic and inorganic carbon dynamics in arid-calcic soils. This study on arid-calcic cropland soils assessed the influence of flood and subsurface drip irrigation on soil organic carbon (SOC) and soil inorganic carbon (SIC) formation as influenced by soil chemical properties and bacterial and fungal biomass. As well, these dynamics were assessed in an unmanaged/unirrigated desert soil. Under drip irrigation, SOC was significantly greater than under flood irrigation, but flood stored more SIC than drip irrigation and no irrigation. The observed SOC–SIC patterns were likely driven by calcium binding. Flood irrigation adds significantly more calcium and bicarbonate to the system, while leaching dissolved organic carbon (DOC). Under flood, calcium is likely more preferentially bound as calcium carbonate. Under drip irrigation, less water was added, calcium and SOC were maintained in the rooting zone where SOC may be stabilized <em>via</em> cation-mediated bridging. Despite higher SOC under drip, more total, and bacterial biomass were detected under flood than drip irrigation, which promoted fungal biomass. Bacterial biomass under flood irrigation may be contributing to microbial carbonate precipitation, supported by the greater presence of common bacterial groups known to contribute to this process, and significant positive relationships with calcium. This research emphasizes the importance of examining SOC and SIC dynamics from abiotic and biotic and particularly microbial perspectives; to optimize soil carbon storage in arid croplands.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109189"},"PeriodicalIF":9.7,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49842898","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":"Contrasting mechanisms of nutrient mobilization in rhizosphere hotspots driven by straw and biochar amendment","authors":"Wenhui Shang ,&nbsp;Bahar S. Razavi ,&nbsp;Shuihong Yao ,&nbsp;Cunkang Hao ,&nbsp;Yakov Kuzyakov ,&nbsp;Evgenia Blagodatskaya ,&nbsp;Jing Tian","doi":"10.1016/j.soilbio.2023.109212","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109212","url":null,"abstract":"<div><p>Straw return strategies are widely used green management practices that can alter soil organic matter transformation and dynamics through changes in microbial community structure and functions. How the exogenous input of organic materials of contrasting qualities affects the composition of dominant taxa, growth, and microbial functional properties related to nutrient acquisition in space remains unclear. In this study, we investigated the hotsopts and kinetics of C- and N-acquiring hydrolases, microbial growth, and bacterial community structure in maize rhizosphere hotspots after the addition of straw and straw-derived biochar using soil zymography, substrate-induced respiration and high-throughput sequencing. Compared with no amendment and maize straw-derived biochar, straw addition increased the growing biomass and microbial specific growth rate by 1.2–1.6 and 1.7–2.0-fold, respectively, indicating the relative dominance of fast-growing r-strategists. This corresponds to an increased relative abundance of the keystone taxa <em>Firmicutes</em> and their gene copies encoding β-1,4-glucosidase (BG) and β-<em>N</em>-acetylglucosaminidase (NAG). The potential activity and affinity (V_max and K_m) of BG increased 2.2 and 1.8 times, respectively, and those of NAG increased 4.0 and 2.0 times, respectively. In contrast, the relative abundance of <em>Actinobacteria</em> belonging to <em>K-</em>strategists increased in the biochar-amended soil. This resulted in slower growth and retarded enzymatic activity than the straw return treatment. Biochar enhanced the root biomass by 31% and increased the rhizosphere hotspot extents of BG and NAG by 26% and 47%, respectively. The highest robustness and modularity of the co-occurrence network indicated a more stable network with biochar input. In summary, the addition of straw accelerated rhizosphere nutrient cycling by triggering microbial growth, especially fast-growth <em>r</em>-strategists (<em>Firmicutes</em>), and synthesizing a large number of enzymes. In contrast, the addition of biochar increased rhizosphere nutrient mobilization by expanding the extent of rhizosphere hotspots to mobilize nutrients from a larger soil volume. This suggests that there are different strategies for nutrient mobilization in the rhizosphere with contrasting exogenous C addition.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109212"},"PeriodicalIF":9.7,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49842896","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":"Threshold-like effect of soil NO3− concentrations on denitrification product N2O/(N2O+N2) ratio is mediated by soil pH","authors":"Bowen Zhang ,&nbsp;Minghua Zhou ,&nbsp;Bo Zhu ,&nbsp;Björn Kemmann ,&nbsp;Lisa Pfülb ,&nbsp;Stefan Burkart ,&nbsp;Hongbin Liu ,&nbsp;Klaus Butterbach-Bahl ,&nbsp;Reinhard Well","doi":"10.1016/j.soilbio.2023.109213","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109213","url":null,"abstract":"<div><p>The interactive effects of soil pH and nitrate (NO₃⁻) availability on denitrification-derived nitrous oxide (N₂O) and dinitrogen (N₂) emissions, as well as N₂O/(N₂O + N₂) product ratio (N₂Oi) remain difficult to evaluate. Here, we consecutively monitored denitrification-derived N₂O and N₂ emissions with different soil pH and NO₃⁻ concentrations by using the artificial ¹⁵N gas flux method in combination with a global meta-analysis of 458 observations to illustrate the interactive effects of soil pH and NO₃⁻ availability on N₂Oi. Isotopic data indicated that pH adjustment through liming significantly and nonlinearly reduced N₂Oi and increased cumulative N₂ emissions. Liming decreased cumulative N₂O emissions by approximately threefold in low NO₃⁻ treatments (<em>p</em> &lt; 0.01), while at high NO₃⁻ treatments liming showed no effect. The meta-analysis revealed a logarithmic relationship between N₂Oi and increasing soil NO₃⁻ concentrations across different soil pH levels, indicating a threshold-like effect of NO₃⁻ concentrations on the reduction of N₂O during denitrification. The threshold NO₃⁻ concentration tends to raise with increasing soil pH. Hence, there were significant interaction effects of soil pH and soil NO₃⁻ concentration on the N₂Oi value. The present study emphasizes the need to consider soil pH and NO₃⁻ concentration interaction effects on denitrification for proposing the effective mitigation practices of denitrification-derived soil N₂O emissions.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109213"},"PeriodicalIF":9.7,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49842897","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":"Fungivorous protists in the rhizosphere of Arabidopsis thaliana – Diversity, functions, and publicly available cultures for experimental exploration","authors":"Antonie H. Estermann ,&nbsp;Justin Teixeira Pereira Bassiaridis ,&nbsp;Anne Loos ,&nbsp;Marcel Dominik Solbach ,&nbsp;Michael Bonkowski ,&nbsp;Sebastian Hess ,&nbsp;Kenneth Dumack","doi":"10.1016/j.soilbio.2023.109206","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109206","url":null,"abstract":"<div><p>In the context of the soil food web, the transfer of plant-fixed energy and carbon to higher trophic levels has traditionally been attributed to two main energy channels: the fungal energy channel and the bacterial energy channel. Historically, protists were overlooked in the fungal energy channel, which was believed to be controlled by fungivorous microarthropods and nematodes. In this study, we investigated fungivorous protists in the rhizosphere of <em>Arabidopsis thaliana</em>. Our findings revealed a notable abundance and diversity of protists that have developed specialized strategies to overcome the protective cell wall of fungi. Among the identified species were two Vampyrellida (Rhizaria) species, namely <em>Theratromyxa weberi</em> and <em>Platyreta germanica</em>, as well as one Arcellinida (Amoebozoa) species, called <em>Cryptodifflugia oviformis</em>. While <em>T. weberi</em> typically consumed entire fungal cells, the other two species perforated fungal cell walls and extracted the cellular contents. We elucidate the feeding strategies and dietary ranges of the amoebae, highlighting the non-uniform nature of fungivory in protists, as different taxa have evolved distinct approaches to access fungi as a food source. Moreover, we provide publicly available cultures of these protists to facilitate further experimental investigations within the research community.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109206"},"PeriodicalIF":9.7,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49897105","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":"Beyond PLFA: Concurrent extraction of neutral and glycolipid fatty acids provides new insights into soil microbial communities","authors":"Stefan Gorka ,&nbsp;Sean Darcy ,&nbsp;Julia Horak ,&nbsp;Bruna Imai ,&nbsp;Moritz Mohrlok ,&nbsp;Erika Salas ,&nbsp;Andreas Richter ,&nbsp;Hannes Schmidt ,&nbsp;Wolfgang Wanek ,&nbsp;Christina Kaiser ,&nbsp;Alberto Canarini","doi":"10.1016/j.soilbio.2023.109205","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109205","url":null,"abstract":"<div><p>The analysis of phospholipid fatty acids (PLFAs) is one of the most common methods used to quantify the abundance, and analyse the community structure, of soil microbes. The PLFA extraction method can yield two additional lipid fractions—neutral lipids and glycolipids—which potentially hold additional, valuable information on soil microbial communities. Yet its quantitative sensitivity on complete neutral lipid (NLFA) and glycolipid fatty acid (GLFA) profiles has never been validated. In this study we tested (i) if the high-throughput PLFA method can be expanded to concurrently extract complete NLFA and GLFA profiles, as well as sterols, (ii) whether taxonomic specificities of signature fatty acids are retained across the three lipid fractions in pure culture strains, and (iii) whether NLFAs and GLFAs allow soil-specific fingerprinting to the same extent as PLFA analysis. By adjusting the polarity of chloroform with 2% ethanol for solid phase extraction, pure lipid standards were fully fractionated into neutral lipids, glycolipids, and phospholipids. Sterols eluted in the neutral lipid fraction, and a betaine lipid co-eluted with phospholipids. We found consistent taxonomic specificities of fatty acid markers across the three lipid fractions by analysing pure culture extracts representative of soil microbes. Fatty acid profiles from soil extracts, however, showed stronger differences between PLFAs, NLFAs, and GLFAs than between soil types. This indicates that PLFAs and NLFAs signify different community properties (biomass vs. carbon storage, putatively), and that GLFAs are sensitive markers for community traits which behave differently than PLFAs. Although we consistently found high abundances of characteristic sterols in fungal extracts, the PLFA extraction method only yielded miniscule amounts of ergosterol from soil extracts. We argue that concomitant measurement of fatty acid profiles from all three lipid fractions is a low-effort and potentially information-rich addition to the PLFA method, and discuss its applicability for soil microbial community analyses.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109205"},"PeriodicalIF":9.7,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49805973","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":"Transferred communities of arbuscular mycorrhizal fungal persist in novel climates and soils","authors":"Martina Janoušková ,&nbsp;Michael Remke ,&nbsp;Nancy Collins Johnson ,&nbsp;Alena Blažková ,&nbsp;Jana Rydlová ,&nbsp;Zuzana Kolaříková ,&nbsp;Matthew A. Bowker","doi":"10.1016/j.soilbio.2023.109190","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109190","url":null,"abstract":"<div><p>Symbiotic mycorrhizal fungi strongly influence plant establishment and growth particularly in harsh environments, whereby sympatric, presumably co-adapted symbionts are considered particularly beneficial. However, the response of transferred sympatric mycorrhizal fungal communities to new environments remains largely ignored. We therefore studied the relative importance of initial inoculum, soil and climatic conditions on the composition, diversity and root colonization ability of arbuscular mycorrhizal fungal (AMF) communities. To do so, we analyzed the AMF communities in an extensive experiment with two ecotypes of <em>Bouteloua gracilis</em> planted in their sites of origin and in four new sites differing in climate and soil properties.</p><p>After three seasons of growth, the sympatric AMF communities were little changed by the new abiotic conditions. The composition of the AMF communities in plant roots was most strongly determined by the initial inoculum, while the contribution of divergent soil and climatic conditions was an order of magnitude smaller. The levels of root colonization by AMF, in contrast, were significantly influenced by climatic and soil conditions and did not differ among communities of different origins. Their pattern indicates that mycorrhiza formation is facilitated in the plant's sympatric soil and climatic conditions, but also that transferred AMF communities adjust mycorrhiza formation to new abiotic conditions.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109190"},"PeriodicalIF":9.7,"publicationDate":"2023-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49847724","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":"Metagenomics reveals the underestimated role of bacteria in the decomposition of downed logs in forest ecosystems","authors":"Lele Qi ,&nbsp;Jie Yuan ,&nbsp;Wenjun Zhang ,&nbsp;Houyi Liu ,&nbsp;Zepu Li ,&nbsp;Roland Bol ,&nbsp;Shuoxin Zhang","doi":"10.1016/j.soilbio.2023.109185","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109185","url":null,"abstract":"<div><p>Downed logs are important structural and functional elements in the material flow of global forest ecosystems. They provide a rich natural substrate resource for microorganisms; however, current laboratory-based methods cannot fully elucidate the complex process of microbial decomposition of downed logs. Therefore, our study investigated the microbial community structure, succession patterns, and underlying environmental factors controlling the decomposition of <em>Pinus tabulaeformis</em> and <em>Quercus aliena</em> var. <em>acuteserrata</em> downed logs at different stages of decomposition in Chinese forest ecosystems. The genomes of the microorganisms present on the logs during different stages were therefore sequenced, and functional genes were annotated and analyzed using the Kyoto Encyclopedia of Genes and Genomes and Carbohydrate-Active enZYmes databases. We found that bacterial abundance was always higher than fungal abundance throughout the decomposition process, reflecting their strong competitive ability. Microbial community structure and function were similar in the early stage (I) and late stages (IV, V) of log decomposition, but those of the middle stages (II, III) differed. With the decomposition of downed logs of <em>Q. aliena</em> var. <em>acuteserrata</em>, there was a fungal succession pattern from <em>Ascomycota</em> to <em>Basidiomycota</em> to <em>Mucoromycetes</em>, but this trend did not occur for <em>P. tabulaeformis</em>. The density, moisture and elemental content of downed logs were the main factors affecting the microbial community. Finally, microbially mediated functions were mainly related to the metabolism of amino acids, carbohydrates and various small molecule carbohydrate enzymes, cellulases, and chitinases in glycoside hydrolases; the taxa sources of the main functions were primarily <em>Proteobacteria</em> and <em>Firmicutes</em> bacteria, reflecting the functional importance of bacteria in the process of downed log decomposition. We conclude that bacteria always play an important role in the process of downed log decomposition and that their role may be far underestimated. Therefore, we believe that the next step should be to expand the study of downed log bacteria, to further clarify the ecological functions of the bacteria on downed logs in natural environments and their relationship with fungi, which may help shed light on the complex decomposition process of downed logs.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109185"},"PeriodicalIF":9.7,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49897106","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":"Beyond the role of climate and soil conditions: Living and dead trees matter for soil biodiversity in mountain forests","authors":"Laureline Leclerc ,&nbsp;Irene Calderón-Sanou ,&nbsp;Camille Martinez-Almoyna ,&nbsp;Yoan Paillet ,&nbsp;Wilfried Thuiller ,&nbsp;Lucie Vincenot ,&nbsp;The Orchamp Consortium,&nbsp;Georges Kunstler","doi":"10.1016/j.soilbio.2023.109194","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109194","url":null,"abstract":"<div><p>While forests’ contributions to people are intimately linked to their soil biodiversity, little is known about how forest soil biodiversity is structured and influenced by forest characteristics. Living and dead trees influence the quantity and the diversity of resources (<em>e.g.</em> litter content) and habitats (<em>e.g.</em> microclimate) available for soil organisms. In this study, we explored the effects of forest characteristics and their relative importance to regional climate and local soil conditions in explaining forest soil biodiversity.</p><p>We characterised forest quantity (abundance of living and dead trees, and dominant tree leaves C/N), and diversity characteristics (tree sizes, deadwood and tree species diversities). We assessed the response of the diversity of 34 soil trophic groups to climate, soil properties and forest characteristics using environmental DNA metabarcoding data along 16 elevational gradients in the French Alps.</p><p>Overall, we showed that climate and soil characteristics explained most of the diversity of soil trophic groups. For the diversity of some groups, however, forest characteristics were important drivers (<em>e.g.</em> ectomycorrhizal fungi). In general, forest diversity characteristics had a positive effect on the diversity of soil trophic groups, in agreement with the resource-heterogeneity hypothesis. We also found that the effects of forest characteristics can percolate to high trophic level groups or to groups that do not have a direct link with living or dead trees (<em>e.g.</em> fungivore mites).</p><p>Forest characteristics can have complex indirect effects that branch out throughout the whole soil food web. Even if mountain forests span large climatic gradients, forest structure and composition can be additional key drivers of soil biodiversity. Thus forest management, by driving forest structure and composition, can have important effects on soil biodiversity in managed forests.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109194"},"PeriodicalIF":9.7,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49805964","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 macroporosity modulates the extent of negative microbial associations during organic substance decomposition","authors":"Qing Xia,&nbsp;Joshua L. Heitman,&nbsp;Wei Shi","doi":"10.1016/j.soilbio.2023.109202","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109202","url":null,"abstract":"<div><p>Microbial species interactions are expected to influence the community-level properties, such as the production of extracellular enzymes and the degradation of organic substances. This work examined how microbial diversity, composition and the overall sign of microbial associations were altered with soil texture and structure following the amendment of organic substances. Two sets of microcosms (1:100 and 1:1) of a 4 × 3 factorial design were constructed, with four artificial textural classes (a sandy loam, two loams, and a (silty) clay loam) and three organics (TSB, tryptic soy broth; CA, a mixture of cellulose and humic/fulvic acids; BS, barley straw). As the ‘microbial inoculant’, an agricultural soil was added to the 1:100 and 1:1 microcosms at 1% and 50%, respectively. A few of microbial taxa were specifically enriched after soil addition of TSB, CA, or BS, but distributions across textural classes were inconsistent between microcosms or between organic amendments. Regardless, top abundant bacterial and fungal OTUs were overall negatively associated, suggesting that microbial competition for the shared resource dominated the decomposition of both simple and complex organics. Microbial associations were also modified by soil pore size distribution (PSD), being fewer negative (or more positive) in soils of greater macroporosity than in soils of lower macroporosity. The PSD-based differences in microbial associations were coordinated with PSD-based differences in the activities of exoglucanase and β-glucosidase in TSB-amended soils or soil respiration characteristics in CA-amended soils. Our results provide new insight into how soil structure regulates microbial interactions and, accordingly, the degradation of organic matter.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109202"},"PeriodicalIF":9.7,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49805972","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":"Seepage-mediated export of bacteria from soil is taxon-specific and driven by seasonal infiltration regimes","authors":"Martina Herrmann ,&nbsp;Katharina Lehmann ,&nbsp;Kai Uwe Totsche ,&nbsp;Kirsten Küsel","doi":"10.1016/j.soilbio.2023.109192","DOIUrl":"https://doi.org/10.1016/j.soilbio.2023.109192","url":null,"abstract":"<div><p>The seepage-mediated translocation of soil microorganisms across the soil-regolith boundary plays a central role in connecting surface and subsurface habitats. However, field studies targeting the factors controlling the dynamics of this translocation are still rare. We aimed to disentangle the effects of taxonomic identity, soil type, land use, and hydrological season on the translocation of bacteria over 1.5 years. Seepage-mediated bacterial transport was assessed using tension-controlled lysimeters in various soil types of a low-mountain groundwater recharge area under a temperate climate. Susceptibility to transport with seepage was primarily taxon-specific while influence by land use played only a minor role. The estimated total export of cells from soil ranged from 5.2 × 10¹¹ to 1.3 × 10¹² cells per m² during a six-months-period and was 1.5 times higher during hydrological winter than in summer. In winter, low ionic strength seepage likely favored the export of bacterial groups with cell sizes of less than 1 μm such as <em>Cand</em>. Patescibacteria or <em>Bdellovibrionaceae</em>, or extracellular stages of potential pathogens of eukaryotes (<em>Chlamydiales</em>, <em>Rickettsiales</em>). <em>Cand</em>. Patescibacteria alone accounted for 40% of the cells exported in winter. Mobile cells contributed 1.3–2.1% to the total organic carbon exported from topsoil and subsoil. Our results demonstrate that substantial bacterial biomass is continuously exported from soils to subsurface environments. Export is strongly driven by the susceptibility of specific bacterial taxa to undergo translocation, and by seasonal infiltration regime. Enhanced introduction of bacterivorous or potential pathogenic taxa from soil to groundwater upon recharge may represent an important controlling factor for bacterial interaction networks or trophic interactions in groundwater food webs.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"187 ","pages":"Article 109192"},"PeriodicalIF":9.7,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49805965","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}