Biogeochemistry最新文献

{"title":"Calcium sorption and isotope fractionation in Bacillus subtilis and Pseudomonas aeruginosa","authors":"N. Nuvoli,&nbsp;A. D. Schmitt,&nbsp;S. Gangloff,&nbsp;V. A. Geoffroy","doi":"10.1007/s10533-024-01178-4","DOIUrl":"10.1007/s10533-024-01178-4","url":null,"abstract":"<div><p>Bacteria are a key component of the critical zone, because of their role in the nutrient availability for the vegetation. There is still little knowledge on the direct role of bacteria on Ca storage/leaching in soils while it is an essential macronutrient for vegetation growth. In recent years, Ca stable isotopes have shown their potential in understanding the Ca biogeochemical cycle. Preliminary studies highlighted that in the presence of soil bacteria, the plant uptake of nutrients is increased due to the mineral bioweathering. Moreover, Ca isotope signatures of nutrient media also showed differences between growth experiments in batch in the presence and absence of bacteria. In this study, the focus is to verify if Ca adsorption and incorporation into/onto bacterial strains induce such isotopic fractionation. Batch experiments were carried out on <i>Pseudomonas aeruginosa</i> (a Gram-negative bacterium) and on the vegetative and sporulated forms of <i>Bacillus subtilis</i> (a Gram-positive bacterium). These experimentations showed that: (i) no observable isotopic fractionations were induced during calcium/bacteria contact for all experimental parameters (pH, kinetic, bacterial cell number, interaction time, dead/alive bacteria); (ii) Ca was mainly stored in the bacterial cell wall compartments. On the other hand, significant Ca isotopic differences between the spores and the sporulation medium (Δ^44/40Ca_{spores–sporulation medium} ranging from − 0.53 to − 1.15‰), suggest isotopic fractionation during the sporulation process, likely occurring during the attachment of Ca to carboxyl acid groups as calcium chelates with dipicolinic acid. The absence of Ca isotope fractionation during Ca sorption on vegetative and sporulated bacteria via passive channels indicates that the tested bacteria’s contribution to the Ca biogeochemical cycle is indirect primary enhancing bioweathering and Ca bioavailability for vegetation. If confirmed by further studies, only the sporulation mechanisms itself may directly impact the Ca biogeochemical cycle.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 12","pages":"1491 - 1510"},"PeriodicalIF":3.9,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01178-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iron as a precursor of aggregation and vector of organic carbon to sediments in a boreal lake","authors":"Simon David Herzog,&nbsp;Viktoriia Mekelesh,&nbsp;Margarida Soares,&nbsp;Ulf Olsson,&nbsp;Per Persson,&nbsp;Emma Sofia Kritzberg","doi":"10.1007/s10533-024-01184-6","DOIUrl":"10.1007/s10533-024-01184-6","url":null,"abstract":"<div><p>While organic matter (OM) interactions in the water column prevent iron (Fe) precipitation and sedimentation, Fe also acts as a precursor of aggregation and a vector of OM to sediments. This study aims to characterize Fe–OM interactions to understand the role of Fe in promoting aggregation and transport of OM. Samples of Fe and OM were collected from water, settling material, and sediment along a gradient starting from the inlet and continuing offshore within a boreal lake. Fe speciation was determined using X-ray absorption spectroscopy (XAS), and the chemical composition of OM was assessed using Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT IR) and Nuclear magnetic resonance spectroscopy (NMR). The results show a decrease in Fe and OM concentrations in the water column with increasing distance from the inlet. Winter sampling revealed a shift in Fe speciation from dominance of organically complexed Fe to an increase in Fe(oxy)hydroxide, accompanied by a loss of aromatic and carboxylate function of OM. Summer sampling revealed no significant changes along the gradient, with Fe(oxy)hydroxide and carbohydrates dominating the water phase. Interestingly, settling particles and surface sediments were dominated by Fe(oxy)hydroxides and aliphatic OM. We propose that phototransformation may be an important process that influences the interaction between Fe and OM and, as a consequence, their fate along the spatial gradient. Our study suggests a photochemically induced loss of carboxylate groups, reflected by an increased carbohydrate-to-carboxylate ratio along the gradient, particularly in winter, and generally lower levels during summer. Loss of carboxylate function promotes the formation of Fe(oxy)hydroxides, which in turn, facilitates the aggregation and sinking of OM, particularly aliphatic components. These insights contribute to a broader understanding of carbon cycling and storage in lakes. Future studies should assess the significance of photochemical processes to OM burial and it how may change given trends in Fe and OM in northern regions.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 12","pages":"1533 - 1552"},"PeriodicalIF":3.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01184-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response of Fe(III)-reducing kinetics, microbial community structure and Fe(III)-related functional genes to Fe(III)-organic matter complexes and ferrihydrite in lake sediment","authors":"Tingyang Shi,&nbsp;Chao Peng,&nbsp;Lu Lu,&nbsp;Zhen Yang,&nbsp;Yundang Wu,&nbsp;Zimeng Wang,&nbsp;Andreas Kappler","doi":"10.1007/s10533-024-01186-4","DOIUrl":"10.1007/s10533-024-01186-4","url":null,"abstract":"<div><p>Microbial Fe(III) reduction significantly influences the fate of various elements and contaminants. Previous research has employed different Fe(III)-OM complexes and ferrihydrite to study Fe(III)-reduction-related biogeochemistry processes. However, the effects of adding specific Fe(III)-OM complexes and ferrihydrite on the Fe(III)-reducing bacterial community, Fe(III)-reducing kinetics, and Fe(III)-related functional genes remain largely unexplored. This study applied microcosm experiments and metagenomic analysis of lake sediments with and without amendments of ferrihydrite, Fe(III)-citrate, or Fe(III)-EDTA. Results showed that sediments amended with Fe(III)-citrate and Fe(III)-EDTA exhibited faster Fe(III) reduction rates and more significant changes in bacterial community structures compared to those amended with ferrihydrite. <i>Geobacter</i> and <i>Clostridium</i> were enriched in the sediments amended with Fe(III)-EDTA and Fe(III)-citrate, respectively. Despite a slower reduction rate and lack of enrichment of specific Fe(III)-reducing bacteria, ferrihydrite still led to an increase in the copy numbers of genes related to Fe(III) reduction and iron assimilation in the metagenomes, suggesting an increase in these capacities. These results suggest that introducing various Fe(III)-OM complexes and ferrihydrite into the environment would result in differences in not only Fe(III) reduction rates and Fe(III)-reducing bacterial communities but also in iron-related functional genes. Meanwhile, variations in Fe(III) reduction rates and Fe(III)-reducing bacterial communities do not necessarily correlate with changes in the abundances of functional genes relevant to Fe(III) reduction and iron assimilation in the metagenomes. These results provide a better understanding of the adaptive mechanisms of Fe(III)-reducing bacteria in different environmental systems.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 12","pages":"1553 - 1565"},"PeriodicalIF":3.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01186-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Persistent biogeochemical signals of land use-driven, deep root losses illuminated by C and O isotopes of soil CO2 and O2","authors":"S. A. Billings,&nbsp;Z. Brecheisen,&nbsp;A. Cherkinsky,&nbsp;C. Lehmeier,&nbsp;C. W. Cook,&nbsp;D. Markewitz,&nbsp;L. F. T. Souza,&nbsp;D. Reuman,&nbsp;D. D. Richter","doi":"10.1007/s10533-024-01177-5","DOIUrl":"10.1007/s10533-024-01177-5","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Replacing long-lived, rarely disturbed vegetation with short-lived, frequently disturbed vegetation is a widespread phenomenon in the Anthropocene that can influence ecosystem functioning and soil development by reducing the abundance of deep roots. We explore how sources and fate of soil CO&lt;sub&gt;2&lt;/sub&gt; vary with organic substrate source, abundance of respiring biota (i.e., roots and soil microbes), season, and soil depth. We quantified multiple isotopic signatures of CO&lt;sub&gt;2&lt;/sub&gt; (δ&lt;sup&gt;13&lt;/sup&gt;C, Δ&lt;sup&gt;14&lt;/sup&gt;C, δ&lt;sup&gt;18&lt;/sup&gt;O) as well as concentrations and δ&lt;sup&gt;18&lt;/sup&gt;O of free O&lt;sub&gt;2&lt;/sub&gt; in the upper 5 m of soil at sites where root abundances and soil organic C have been previously quantified: in late-successional forests, cultivated fields, and ~ 80 y old regenerating pine forests growing on previously cultivated land. We hypothesized that soil CO&lt;sub&gt;2&lt;/sub&gt;sources would vary across soil depth and land cover, reflecting varying abundances of organic substrates, and seasonally as the dominance of root vs. microbial CO&lt;sub&gt;2&lt;/sub&gt; production changes through the year. δ&lt;sup&gt;13&lt;/sup&gt;C–CO&lt;sub&gt;2&lt;/sub&gt; revealed respiration of C4-derived substrates in cultivated fields particularly during the growing season. This effect was not evident in soils of regenerating pine or older hardwood forests, suggesting that ~ 80 y of pine inputs to reforested soils have been sufficient to dominate microbial substrate selection over any remnant, historic agricultural C4 inputs. Δ&lt;sup&gt;14&lt;/sup&gt;C–CO&lt;sub&gt;2&lt;/sub&gt; diverged by land use at 3 and 5 m, indicating that more recently-produced photosynthate is available for mineralization in forests compared to cultivated plots, and in late-successional forests compared to regenerating pine forests. At 1.5, 3, and 5 m in forested plots we observed evidence of respiratory demands on soil pore space O&lt;sub&gt;2&lt;/sub&gt;. In these soils, we observed declines in [O&lt;sub&gt;2&lt;/sub&gt;] compared to other depths and to the agricultural plots and concurrent increases in δ&lt;sup&gt;18&lt;/sup&gt;O of free O&lt;sub&gt;2&lt;/sub&gt;, consistent with the idea that roots and heterotrophic soil microbes are more active where photosynthate is more available. The δ&lt;sup&gt;18&lt;/sup&gt;O–CO&lt;sub&gt;2&lt;/sub&gt; values, a likely proxy for δ&lt;sup&gt;18&lt;/sup&gt;O of soil porewater, exhibited &lt;sup&gt;18&lt;/sup&gt;O enrichment during the winter, when many sampling wells were flooded, compared to growing season values. These data suggest an isotopically-distinct and laterally-flowing source of CO&lt;sub&gt;2&lt;/sub&gt;-laden porewater during winter months. Combined, these datasets document how ~ 80 y of forest regeneration can provide sufficient C inputs to mask any microbial mineralization of decades-old organic inputs, but belowground C inputs still lag those of late successional forests. We also infer that lateral and vertical flows of water can serve as a sink for biotically-generated CO&lt;sub&gt;2&lt;/sub&gt;, and that where deep soil [CO&lt;sub&gt;2&lt;/sub&gt;] is lower due to lower root and microbial activities, production of c","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 12","pages":"1469 - 1489"},"PeriodicalIF":3.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01177-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142385604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature sensitivity of soil respiration declines with climate warming in subalpine and alpine grassland soils","authors":"Khatab Abdalla,&nbsp;Larissa Schierling,&nbsp;Yue Sun,&nbsp;Max A. Schuchardt,&nbsp;Anke Jentsch,&nbsp;Thomas Deola,&nbsp;Peter Wolff,&nbsp;Ralf Kiese,&nbsp;Eva Lehndorff,&nbsp;Johanna Pausch,&nbsp;Nele Meyer","doi":"10.1007/s10533-024-01179-3","DOIUrl":"10.1007/s10533-024-01179-3","url":null,"abstract":"<div><p>Warming as a climate change phenomenon affects soil organic matter dynamics, especially in high elevation ecosystems. However, our understanding of the controls of soil organic matter mineralization and dynamics remains limited, particularly in alpine (above treeline) and subalpine (below treeline) grassland ecosystems. Here, we investigated how downslope (warming) and upslope (cooling) translocations, in a 5-years reciprocal transplanting experiment, affects soil respiration and its temperature sensitivity (Q10), soil aggregation, and soil organic matter carbon (C) and nitrogen (N) composition (C/N ratio). Downslope translocation of the alpine (2440 m a.s.l.) and subalpine (1850 m a.s.l.) to the lowland site (350 m a.s.l.) resulted in a temperature change during the growing seasons of + 4.4K and + 3.3K, respectively. Warming of alpine soils (+ 4.4K) reduced soil organic carbon (SOC) content by 32%, which was accompanied by a significant decrease of soil macroaggregates. Macroaggregate breakdown induced an increased respiration quotient (qCO₂) by 27% following warming of alpine soils. The increase in qCO₂ respiration was associated with a significant decrease (from 2.84 ± 0.05 to 2.46 ± 0.05) in Q10, and a change in soil organic matter composition (lower C/N ratios). Cooling did not show the opposite patterns to warming, implying that other mechanisms, such as plant and microbial community shifts and adaptation, were involved. This study highlights the important role of SOC degradability in regulating the temperature response of soil organic matter mineralization. To predict the adverse effect of warming on soil CO₂ release and, consequently, its negative feedback on climate change, a comprehensive understanding of the mechanisms of C storage and turnover is needed, especially at high elevations in the Alps that are particularly affected by rising temperatures.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 11","pages":"1453 - 1467"},"PeriodicalIF":3.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01179-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142385605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iron fertilization and soil carbon sequestration in rice paddies","authors":"Snowie Jane C. Galgo,&nbsp;Lorraine Joule B. Estrada,&nbsp;So Yeong Park,&nbsp;Ronley C. Canatoy,&nbsp;Muhammad Israr Khan,&nbsp;Benjamin L. Turner,&nbsp;Pil Joo Kim","doi":"10.1007/s10533-024-01183-7","DOIUrl":"10.1007/s10533-024-01183-7","url":null,"abstract":"<div><p>Iron (Fe) fertilization of the ocean mitigates global warming by sequestering carbon dioxide (CO₂) in phytoplankton, but the effect of Fe fertilization on carbon (C) sequestration in arable soils remains unknown. Iron is often added to rice paddies as blast furnace slag (BFS), a byproduct of steel manufacturing used as a silicon (Si) fertilizer to improve productivity. However, BFS also contains large amounts of Fe oxides, which might promote C sequestration by forming complexes with organic matter. To investigate this, we first analyzed data from a national survey of soils from South Korea to estimate the effect of continuous Fe addition via BFS on soil organic C (SOC) stocks. This revealed a strong positive correlation between SOC and extractable Fe and available Si concentrations, indicating that periodic silicate fertilizer application contributed to an increase in SOC stock. Second, to isolate the effect of Fe addition on SOC stocks, we conducted an incubation test with BFS enriched with Fe oxides (0–5%, wt wt⁻¹). Soil respiration was significantly reduced by silicate fertilizer application, and this effect was strengthened with the Fe-enriched fertilizer. Finally, to verify the effect of Fe addition on SOC stock changes in the field, we added three different Fe-enriched silicate fertilizers to rice paddies and quantified SOC stock changes by net ecosystem C budget (NECB) estimation. Silicate fertilizer significantly increased net primary production (NPP) by 18–20% over the control, and this effect was strengthened with increasing Fe addition. Silicate fertilizer application decreased soil respiration by 15–30% over the control, and this effect was strengthened further by Fe enrichment. As a result, silicate fertilizer application during rice cultivation increased the SOC stock by 0.65–0.68 Mg C ha⁻¹ over the control and by 0.90–0.96 Mg C ha⁻¹ for Fe-enriched fertilizer. In conclusion, the positive effect of BFS addition on SOC stock is related in part to the role of Fe oxides, primarily through the suppression of soil respiration. Fe-enriched silicate fertilizer therefore provides a management strategy to increase SOC stocks and crop productivity in rice paddies.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 11","pages":"1437 - 1452"},"PeriodicalIF":3.9,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01183-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142385603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How the effect of earthworms on soil organic matter mineralization and stabilization is affected by litter quality and stage of soil development","authors":"Saliha Irshad,&nbsp;Jan Frouz","doi":"10.1007/s10533-024-01182-8","DOIUrl":"10.1007/s10533-024-01182-8","url":null,"abstract":"<div><p>Globally soil fauna consumes about half of the annual litter fall. An important question is how this activity affects the mineralization and stabilization of soil organic matter. Here we explore how much earthworms influence the decomposition of litter and the stabilization of organic matter in soils at various stages of soil development (various soil age) that are supplied with litter of various quality. The laboratory mesocosms consist of litter and a mineral layer. The mineral soils originated either from spruce and alder stands growing either on post-mining soils (young soils after about 50 years of soil development) or from soils in the close vicinity of post-mining sites (mature soils with several thousand years of soil development), the mineral soils were supplied by matching litter, the mesocosms were either without earthworms or with two individuals of earthworms. The earthworm effect showed statistically significant interaction with tree and soil age: earthworms increased respiration in both alder soils, but in spruce soils only in mature soil, while the opposite was true for young soils. In general, earthworms promoted the removal of litter from the soil surface and carbon accumulation in the mineral soil. Earthworms promoted C storage in mineral associated organic matter (MAOM), especially in young spruce soils. The results suggested that earthworm activity in young soils which were far from saturation (spruce on post-mining soils) promotes soil C sequestration by promoting C storage in MAOM, whereas earthworms in mature, C saturated soils tend to promote soil respiration. More broadly, earthworms effect on soil depends on stage of soil C saturation.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 11","pages":"1425 - 1436"},"PeriodicalIF":3.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01182-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142377700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rainfall events stimulate episodic associative nitrogen fixation in switchgrass","authors":"Carmella Vizza,&nbsp;Matthew A. Belanger,&nbsp;Jabarius Jones,&nbsp;Sean J. Murphy,&nbsp;Daniel H. Buckley,&nbsp;G. Philip Robertson,&nbsp;Sarah S. Roley","doi":"10.1007/s10533-024-01180-w","DOIUrl":"10.1007/s10533-024-01180-w","url":null,"abstract":"<div><p>Associative N₂ fixation (ANF) is widespread but poorly characterized, limiting our ability to estimate global inputs from N₂ fixation. In some places, ANF rates are at or below detection most of the time but occasionally and unpredictably spiking to very high rates. Here we test the hypothesis that plant phenology and rainfall events stimulate ANF episodes. We measured ANF in intact soil cores in switchgrass (<i>Panicum virgatum</i> L.) in Michigan, USA. We used rain exclusion shelters to impose three rainfall treatments with each receiving 60 mm of water over a 20-day period but at different frequencies. We concurrently established a treatment that received ambient rainfall, and all four treatments were replicated four times. To assess the effects of plant phenology, we measured ANF at key phenological stages in the ambient treatment. To assess the effects of rainfall, we measured ANF immediately before and immediately after each wetting event in each treatment involving rainfall manipulation. We found that the previous day’s rainfall could explain 29% of the variation in ANF rates within the ambient treatment alone, and that bulk soil C:N ratio was also positively correlated with ANF, explaining 18% of the variation alone. Wetting events increased ANF and the magnitude of response to wetting increased with the amount of water added and decreased with the amount of inorganic N added in water. ANF episodes thus appear to be driven primarily by wetting events. Wetting events likely increase C availability, promote microbial growth, and make rhizosphere conditions conducive to ANF.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 11","pages":"1409 - 1424"},"PeriodicalIF":3.9,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01180-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142374237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial nitrogen transformations in tundra soil depend on interactive effects of seasonality and plant functional types","authors":"Marianne Koranda,&nbsp;Anders Michelsen","doi":"10.1007/s10533-024-01176-6","DOIUrl":"10.1007/s10533-024-01176-6","url":null,"abstract":"<div><p>Nitrogen (N) cycling in organic tundra soil is characterised by pronounced seasonal dynamics and strong influence of the dominant plant functional types. Such patterns in soil N-cycling have mostly been investigated by the analysis of soil N-pools and net N mineralisation rates, which, however, yield little information on soil N-fluxes. In this study we investigated microbial gross N-transformations, as well as concentrations of plant available N-forms in soils under two dominant plant functional types in tundra heath, dwarf shrubs and mosses, in subarctic Northern Sweden. We collected organic soil under three dwarf shrub species of distinct growth form and three moss species in early and late growing season. Our results showed that moss sites were characterised by significantly higher microbial N-cycling rates and soil N-availability than shrub sites. Protein depolymerisation, the greatest soil N-flux, as well as gross nitrification rates generally did not vary significantly between early and late growing season, whereas gross N mineralisation rates and inorganic N availability markedly dropped in late summer at most sites. The magnitude of the seasonal changes in N-cycling, however, clearly differed among plant functional types, indicating interactive effects of seasonality and plant species on soil N-cycling. Our study highlights that the spatial variation and seasonal dynamics of microbial N transformations and soil N availability in tundra heath are intimately linked with the distinct influence of plant functional types on soil microbial activity and the plant species-specific patterns of nutrient uptake and carbon assimilation. This suggests potential strong impacts of future global change-induced shifts in plant community composition on soil N-cycling in tundra ecosystems.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 11","pages":"1391 - 1408"},"PeriodicalIF":3.9,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01176-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142101621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Short-term warming decreased soil DOM content and microbial species in alpine wetlands but increased soil DOM content and hydrolase activity in alpine meadows on the Tibetan Plateau","authors":"Shiyu Fan,&nbsp;Jihong Qin,&nbsp;Hui Sun,&nbsp;Zhenchu Dan,&nbsp;Wenqing Chen,&nbsp;Jiyuan Yang","doi":"10.1007/s10533-024-01171-x","DOIUrl":"10.1007/s10533-024-01171-x","url":null,"abstract":"<div><p>As important carbon sinks, alpine wetlands on the Tibetan Plateau are undergoing severe degradation. To reveal warming-induced ecological shifts in alpine environments, this study determined soil nutrient contents, enzyme activities, absorption and fluorescence spectra and quadrupole time-of-flight mass spectra (metabolomes) of dissolved organic matter (DOM) and metagenomes based on short-term incubation (0 °C, 10 °C and 20 °C) of topsoil from alpine wetlands and meadows (degraded wetlands). Compared with meadows, wetlands had higher contents of soil DOM (dissolved organic carbon, dissolved organic nitrogen and dissolved phosphorous) and greater activities of hydrolases (β-glucosidase, cellobiohydrolase, β-N-acetylglucosaminidase and acid phosphatase), with those parameters all being highest at 20 °C in meadows and showing various dynamics in wetlands. Soil DOM in wetlands presented the lowest values of specific ultraviolet absorbances (SUVA₂₅₄ and SUVA₂₆₀) at 0 °C and the highest values at 10 °C, whereas the opposite was true in the meadows. Wetland soils had greater diversities of DOM molecular compositions and microbial communities, with warming gradually increasing the number of identified DOM compounds in meadows and decreasing the number of microbial species in both soils. Wetland soils had more <i>Proteobacteria</i> (44.2%) and <i>Acidobacteria</i> (21.1%) and fewer <i>Actinobacteria</i> (18.0%) than meadow soils and contained many temperature-sensitive archaea (which were abundant at 0 °C). Distance-based redundancy analysis and Procrustes analysis indicated the greater complexity of ecological responses in alpine wetlands, which may be attributed to the higher adaptive capacity of soil microbial communities. Our results suggest that both degradation and warming decrease soil DOM content and microbial activities in alpine wetlands, providing important references for alpine wetland conservation under current climate change.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 11","pages":"1371 - 1390"},"PeriodicalIF":3.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01171-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142085535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}