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1.
Ester M. Eckert Grazia M. Quero Andrea Di Cesare Giuliana Manfredini Francesca Mapelli Sara Borin Diego Fontaneto Gian Marco Luna Gianluca Corno 《Molecular ecology》2019,28(5):1170-1182
Notwithstanding the fundamental role that environmental microbes play for ecosystem functioning, data on how microbes react to disturbances are still scarce, and most factors that confer stability to microbial communities are unknown. In this context, antibiotic discharge into the environment is considered a worldwide threat for ecosystems with potential risks to human health. We therefore tested resilience of microbial communities challenged by the presence of an antibiotic. In a continuous culture experiment, we compared the abundance, composition and diversity of microbial communities undisturbed or disturbed by the constant addiction of tetracycline in low (10 µg/L) or intermediate (100 µg/L) concentration (press disturbance). Further, the bacterial communities in the three treatments had to face the sudden pulse disturbance of adding an allochthonous bacterium (Escherichia coli). Tetracycline, even at low concentrations, affected microbial communities by changing their phylogenetic composition and causing cell aggregation. This, however, did not coincide with a reduced microbial diversity, but was mainly caused by a shift in dominance of specific bacterial families. Moreover, the less disturbed community (10 µg/L tetracycline) was sometimes more similar to the control and sometimes more similar to heavily disturbed community (100 µg/L tetracycline). All in all, we could not see a pattern where the communities disturbed with antibiotics were less resilient to a second disturbance introducing E. coli, but they seemed to be able to buffer the input of the allochthonous strain in a similar manner as the control. 相似文献
2.
He Nianpeng Wang Ruomeng Gao Yang Dai Jingzhong Wen Xuefa Yu Guirui 《Ecology and evolution》2013,3(15):5045-5054
Understanding the temperature sensitivity (Q10) of soil organic matter (SOM) decomposition is important for predicting soil carbon (C) sequestration in terrestrial ecosystems under warming scenarios. Whether Q10 varies predictably with ecosystem succession and the ways in which the stoichiometry of input SOM influences Q10 remain largely unknown. We investigate these issues using a grassland succession series from free‐grazing to 31‐year grazing‐exclusion grasslands in Inner Mongolia, and an incubation experiment performed at six temperatures (0, 5, 10, 15, 20, and 25°C) and with four substrates: control (CK), glucose (GLU), mixed grass leaf (GRA), and Medicago falcata leaf (MED). The results showed that basal soil respiration (20°C) and microbial biomass C (MBC) logarithmically decreased with grassland succession. Q10 decreased logarithmically from 1.43 in free‐grazing grasslands to 1.22 in 31‐year grazing‐exclusion grasslands. Q10 increased significantly with the addition of substrates, and the Q10 levels increased with increase in N:C ratios of substrate. Moreover, accumulated C mineralization was controlled by the N:C ratio of newly input SOM and by incubation temperature. Changes in Q10 with grassland ecosystem succession are controlled by the stoichiometry of newly input SOM, MBC, and SOM quality, and the combined effects of which could partially explain the mechanisms underlying soil C sequestration in the long‐term grazing‐exclusion grasslands in Inner Mongolia, China. The findings highlight the effect of substrate stoichiometry on Q10 which requires further study. 相似文献
3.
Rhododendron aureum Georgi is a perennial evergreen dwarf shrub that grows at all elevations within the alpine tundra of northern China. Previous research has investigated the plant communities of R. aureum; however, little information is available regarding interspecific competition and underground soil microbial community composition. The objective of our study was to determine whether the presence of R. aureum creates a unique soil microbiome and to investigate the relationship between R. aureum and other plant species. Our study site ranged from 1,800 to 2,600 m above sea level on the northern slope of the Changbai Mountain. The results show that the soil from sites with an R. aureum community had a higher abundance of nitrogen‐fixing bacteria and a higher resistance to pathogens than soils from sites without R. aureum. We emphasize that R. aureum promotes a unique soil microbial community structure that is distinct from those associated with other plants. Elevation and microbial biomass were the main influencing factors for plant community structure. Analysis of interspecific relationships reveals that R. aureum is negatively associated with most other dominant shrubs and herbs, suggesting interspecific competition. It is necessary to focus on other dominant species if protection and restoration of the R. aureum competition is to occur. In the future, more is needed to prove whether R. aureum decreases species diversity in the tundra ecosystems of Changbai Mountain. 相似文献
4.
Yong‐Liang Chen Jin‐Zhi Ding Yun‐Feng Peng Fei Li Gui‐Biao Yang Li Liu Shu‐Qi Qin Kai Fang Yuan‐He Yang 《Journal of Biogeography》2016,43(10):2027-2039
5.
Andrew T. Nottingham Erland Bth Stephanie Reischke Norma Salinas Patrick Meir 《Global Change Biology》2019,25(3):827-838
Terrestrial biogeochemical feedbacks to the climate are strongly modulated by the temperature response of soil microorganisms. Tropical forests, in particular, exert a major influence on global climate because they are the most productive terrestrial ecosystem. We used an elevation gradient across tropical forest in the Andes (a gradient of 20°C mean annual temperature, MAT), to test whether soil bacterial and fungal community growth responses are adapted to long‐term temperature differences. We evaluated the temperature dependency of soil bacterial and fungal growth using the leucine‐ and acetate‐incorporation methods, respectively, and determined indices for the temperature response of growth: Q10 (temperature sensitivity over a given 10oC range) and Tmin (the minimum temperature for growth). For both bacterial and fungal communities, increased MAT (decreased elevation) resulted in increases in Q10 and Tmin of growth. Across a MAT range from 6°C to 26°C, the Q10 and Tmin varied for bacterial growth (Q10–20 = 2.4 to 3.5; Tmin = ?8°C to ?1.5°C) and fungal growth (Q10–20 = 2.6 to 3.6; Tmin = ?6°C to ?1°C). Thus, bacteria and fungi did not differ significantly in their growth temperature responses with changes in MAT. Our findings indicate that across natural temperature gradients, each increase in MAT by 1°C results in increases in Tmin of microbial growth by approximately 0.3°C and Q10–20 by 0.05, consistent with long‐term temperature adaptation of soil microbial communities. A 2°C warming would increase microbial activity across a MAT gradient of 6°C to 26°C by 28% to 15%, respectively, and temperature adaptation of microbial communities would further increase activity by 1.2% to 0.3%. The impact of warming on microbial activity, and the related impact on soil carbon cycling, is thus greater in regions with lower MAT. These results can be used to predict future changes in the temperature response of microbial activity over different levels of warming and over large temperature ranges, extending to tropical regions. 相似文献
6.
Mingzhe Ma Zhenhua Zang Zongqiang Xie Quansheng Chen Wenting Xu Changming Zhao Guozhen shen 《Ecology and evolution》2019,9(22):12846-12857
7.
全球变暖对陆地生态系统造成一系列生态问题,使这些问题将随着全球平均气温的升高而进一步加剧。海拔梯度变化是研究气候变暖对陆地生态系统影响的一种重要手段。目前为止利用海拔梯度对微生物影响的研究尚未定论,其主要原因是忽略了植被类型的影响。因此,以中亚热带戴云山的3个海拔(1300、1450、1600 m)的黄山松(Pinus taiwanensis)林为研究对象,探究沿海拔梯度的变化,森林土壤微生物生物量和微生物群落结构的响应变化。结果表明:土壤碳氮磷养分(SOC、TN、TP)、微生物生物量氮(MBN)、微生物生物量磷(MBP)和丛枝菌根真菌(AMF)、革兰氏阴性菌(GN)、真菌(Fungi)、总磷脂脂肪酸(T_(PLFA)),细菌∶真菌(F∶B)均随海拔升高显著下降,而革兰氏阳性菌∶革兰氏阴性菌(GP∶GN)随海拔升高呈相反的趋势。冗余分析(RDA)表明,温度(T)和可溶性有机氮(DON)是影响微生物群落结构的最重要的环境因子。研究表明:与1600 m海拔相比,1300 m海拔温度较高,土壤有机质矿化作用较强,土壤速效养分及微生物生物量随之增加,从而提高(Fungi)、细菌(Bacteria)等。因此,未来气候变暖将通过改变土壤碳氮磷养分来影响本区域微生物群落组成结构。这对进一步深入了解气候变化对山地生态系统土壤养分循环过程具有重要意义。 相似文献
8.
The decomposition of soil organic matter (SOM) can be described by a set of kinetic principles, environmental constraints, and substrate supply. Here, we hypothesized that SOM decomposition rates (R) and its temperature sensitivity (Q10) would increase steadily with the N:C ratios of added substrates by alleviating N limitation on microbial growth. We tested this hypothesis by investigating SOM decomposition in both grassland and forest soils after addition of substrates with a range of N:C ratios. The results showed that Michaelis–Menten equations well fit the response of R to the N:C ratio variations of added substrates, and their coefficients of determination (R2) ranged from 0.65 to 0.89 (P < 0.01). Moreover, the maximal R, Q10, and cumulative C emission of SOM decomposition increased exponentially with the N:C ratios of added substrates, and were controlled interactively by incubation temperature and the N:C ratios of the added substrates. We demonstrated that SOM decomposition rate and temperature sensitivity were exponentially correlated to substrate stoichiometry (N:C ratio) in both grassland and forest soils. Therefore, these correlations should be incorporated into the models for the prediction of SOM decomposition rate under warmer climatic scenarios. 相似文献
9.
土壤微生物学特性对土壤健康的指示作用 总被引：70，自引：0，他引：70
土壤健康是陆地生态系统可持续发展的基础。作者通过概述土壤微生物学特性(土壤微生物群落结构、土壤微生物生物量、土壤酶活性)与土壤质量的关系, 阐明了土壤微生物对土壤健康的生物指示功能。研究表明: 土壤中细菌、真菌和放线菌的组成及其所占比率在一定程度上反映了土壤的肥力水平: 在土壤性质和肥水条件较好的土壤中, 细菌所占比率较高。土壤微生物生物量与土壤有机质含量密切相关, 而且土壤微生物生物量碳与土壤有机碳的比值(Cmic : Corg)和土壤微生物代谢熵(qCO2)的变化在一定程度上反映了土壤有机碳的利用效率。一般情况下, 土壤酶活性高的土壤中, 土壤微生物生物量碳、氮含量也高。因此, 土壤微生物学特性可以反映土壤质量的变化, 并可用作评价土壤健康的生物指标。 相似文献
10.
Andrew T. Nottingham Jeanette Whitaker Nick J. Ostle Richard D. Bardgett Niall P. McNamara Noah Fierer Norma Salinas Adan J. Q. Ccahuana Benjamin L. Turner Patrick Meir 《Ecology letters》2019,22(11):1889-1899
Tropical soils contain huge carbon stocks, which climate warming is projected to reduce by stimulating organic matter decomposition, creating a positive feedback that will promote further warming. Models predict that the loss of carbon from warming soils will be mediated by microbial physiology, but no empirical data are available on the response of soil carbon and microbial physiology to warming in tropical forests, which dominate the terrestrial carbon cycle. Here we show that warming caused a considerable loss of soil carbon that was enhanced by associated changes in microbial physiology. By translocating soils across a 3000 m elevation gradient in tropical forest, equivalent to a temperature change of ± 15 °C, we found that soil carbon declined over 5 years by 4% in response to each 1 °C increase in temperature. The total loss of carbon was related to its original quantity and lability, and was enhanced by changes in microbial physiology including increased microbial carbon‐use‐efficiency, shifts in community composition towards microbial taxa associated with warmer temperatures, and increased activity of hydrolytic enzymes. These findings suggest that microbial feedbacks will cause considerable loss of carbon from tropical forest soils in response to predicted climatic warming this century. 相似文献
11.
Luca Bragazza Alexandre Buttler Bjorn J.M. Robroek Remy Albrecht Claudio Zaccone Vincent E.J. Jassey Constant Signarbieux 《Global Change Biology》2016,22(12):4114-4123
Extreme climate events are predicted to become more frequent and intense. Their ecological impacts, particularly on carbon cycling, can differ in relation to ecosystem sensitivity. Peatlands, being characterized by peat accumulation under waterlogged conditions, can be particularly sensitive to climate extremes if the climate event increases soil oxygenation. However, a mechanistic understanding of peatland responses to persistent climate extremes is still lacking, particularly in terms of aboveground–belowground feedback. Here, we present the results of a transplantation experiment of peat mesocosms from high to low altitude in order to simulate, during 3 years, a mean annual temperature c. 5 °C higher and a mean annual precipitation c. 60% lower. Specifically, we aim at understanding the intensity of changes for a set of biogeochemical processes and their feedback on carbon accumulation. In the transplanted mesocosms, plant productivity showed a species‐specific response depending on plant growth forms, with a significant decrease (c. 60%) in peat moss productivity. Soil respiration almost doubled and Q10 halved in the transplanted mesocosms in combination with an increase in activity of soil enzymes. Spectroscopic characterization of peat chemistry in the transplanted mesocosms confirmed the deepening of soil oxygenation which, in turn, stimulated microbial decomposition. After 3 years, soil carbon stock increased only in the control mesocosms whereas a reduction in mean annual carbon accumulation of c. 30% was observed in the transplanted mesocosms. Based on the above information, a structural equation model was built to provide a mechanistic understanding of the causal connections between peat moisture, vegetation response, soil respiration and carbon accumulation. This study identifies, in the feedback between plant and microbial responses, the primary pathways explaining the reduction in carbon accumulation in response to recurring climate extremes in peat soils. 相似文献
12.
Luke M. Evans Sobadini Kaluthota David W. Pearce Gerard J. Allan Kevin Floate Stewart B. Rood Thomas G. Whitham 《Ecology and evolution》2016,6(13):4565-4581
Temperate forest tree species that span large geographical areas and climatic gradients often have high levels of genetic variation. Such species are ideal for testing how neutral demographic factors and climate‐driven selection structure genetic variation within species, and how this genetic variation can affect ecological communities. Here, we quantified genetic variation in vegetative phenology and growth traits in narrowleaf cottonwood, Populus angustifolia, using three common gardens planted with genotypes originating from source populations spanning the species' range along the Rocky Mountains of North America (ca. 1700 km). We present three main findings. First, we found strong evidence of divergent selection (QST > FST) on fall phenology (bud set) with adaptive consequences for frost avoidance. We also found evidence for selection on bud flush duration, tree height, and basal diameter, resulting in population differentiation. Second, we found strong associations with climate variables that were strongly correlated with latitude of origin. More strongly differentiated traits also showed stronger climate correlations, which emphasizes the role that climate has played in divergent selection throughout the range. We found population × garden interaction effects; for some traits, this accounted for more of the variance than either factor alone. Tree height was influenced by the difference in climate of the source and garden locations and declined with increasing transfer distance. Third, growth traits were correlated with dependent arthropod community diversity metrics. Synthesis. Overall, we conclude that climate has influenced genetic variation and structure in phenology and growth traits and leads to local adaptation in P. angustifolia, which can then impact dependent arthropod species. Importantly, relocation of genotypes far northward or southward often resulted in poor growth, likely due to a phenological mismatch with photoperiod, the proximate cue for fall growth cessation. Genotypes moved too far southward suffer from early growth cessation, whereas those moved too far northward are prone to fall frost and winter dieback. In the face of current and forecasted climate change, habitat restoration, forestry, and tree breeding efforts should utilize these findings to better match latitudinal and climatic source environments with management locations for optimal future outcomes. 相似文献
13.
QST, a measure of quantitative genetic differentiation among populations, is an index that can suggest local adaptation if QST for a trait is sufficiently larger than the mean FST of neutral genetic markers. A previous method by Whitlock and Guillaume derived a simulation resampling approach to statistically test for a difference between QST and FST, but that method is limited to balanced data sets with offspring related as half‐sibs through shared fathers. We extend this approach (i) to allow for a model more suitable for some plant populations or breeding designs in which offspring are related through mothers (assuming independent fathers for each offspring; half‐sibs by dam); and (ii) by explicitly allowing for unbalanced data sets. The resulting approach is made available through the R package QstFstComp. 相似文献
14.
海拔对辽东栎林地土壤微生物群落的影响 总被引：10，自引：0，他引：10
以北京东灵山辽东栎林地土壤为对象,运用氯仿熏蒸-浸提法及磷脂脂肪酸分析(PLFA)法,研究林木生长季节土壤微生物群落随海拔梯度的变化特征.结果表明:随着海拔升高,辽东栎林土壤微生物生物量碳、氮,以及微生物各类群含量均有差异但不显著;土壤细菌/真菌升高,而革兰氏阳性菌(G+)/革兰氏阴性菌(G-)降低.土壤微生物生物量碳、氮以及细菌、真菌、G+细菌、G-细菌的含量与土壤含水量、有机碳、全氮呈显著正相关,土壤真菌含量与土壤碳氮比值呈正相关.土壤微生物群落组成结构(细菌/真菌和G+细菌/G-细菌)的变化主要受土壤温度和土壤含水量的显著影响,说明土壤微生物群落结构对环境条件的变化敏感.随着全球变暖的加剧,暖温带辽东栎林地土壤真菌和G+细菌的比例有升高的趋势. 相似文献
15.
Neal E. Flanagan Hongjun Wang Scott Winton Curtis J. Richardson 《Global Change Biology》2020,26(7):3930-3946
Worldwide, regularly recurring wildfires shape many peatland ecosystems to the extent that fire‐adapted species often dominate plant communities, suggesting that wildfire is an integral part of peatland ecology rather than an anomaly. The most destructive blazes are smoldering fires that are usually initiated in periods of drought and can combust entire peatland carbon stores. However, peatland wildfires more typically occur as low‐severity surface burns that arise in the dormant season when vegetation is desiccated, and soil moisture is high. In such low‐severity fires, surface layers experience flash heating, but there is little loss of underlying peat to combustion. This study examines the potential importance of such processes in several peatlands that span a gradient from hemiboreal to tropical ecozones and experience a wide range of fire return intervals. We show that low‐severity fires can increase the pool of stable soil carbon by thermally altering the chemistry of soil organic matter (SOM), thereby reducing rates of microbial respiration. Using X‐ray photoelectron spectroscopy and Fourier transform infrared, we demonstrate that low‐severity fires significantly increase the degree of carbon condensation and aromatization of SOM functional groups, particularly on the surface of peat aggregates. Laboratory incubations show lower CO2 emissions from peat subjected to low‐severity fire and predict lower cumulative CO2 emissions from burned peat after 1–3 years. Also, low‐severity fires reduce the temperature sensitivity (Q10) of peat, indicating that these fires can inhibit microbial access to SOM. The increased stability of thermally altered SOM may allow a greater proportion of organic matter to survive vertical migration into saturated and anaerobic zones of peatlands where environmental conditions physiochemically protect carbon stores from decomposition for thousands of years. Thus, across latitudes, low‐severity fire is an overlooked factor influencing carbon cycling in peatlands, which is relevant to global carbon budgets as climate change alters fire regimes worldwide. 相似文献
16.
The western Antarctic Peninsula is an extreme low temperature environment that is warming rapidly due to global change. Little is known, however, on the temperature sensitivity of growth of microbial communities in Antarctic soils and in the surrounding oceanic waters. This is the first study that directly compares temperature adaptation of adjacent marine and terrestrial bacteria in a polar environment. The bacterial communities in the ocean were adapted to lower temperatures than those from nearby soil, with cardinal temperatures for growth in the ocean being the lowest so far reported for microbial communities. This was reflected in lower minimum (Tmin) and optimum temperatures (Topt) for growth in water (?17 and +20°C, respectively) than in soil (?11 and +27°C), with lower sensitivity to changes in temperature (Q10; 0–10°C interval) in Antarctic water (2.7) than in soil (3.9). This is likely due to the more stable low temperature conditions of Antarctic waters than soils, and the fact that maximum in situ temperatures in water are lower than in soils, at least in summer. Importantly, the thermally stable environment of Antarctic marine water makes it feasible to create a single temperature response curve for bacterial communities. This would thus allow for calculations of temperature‐corrected growth rates, and thereby quantifying the influence of factors other than temperature on observed growth rates, as well as predicting the effects of future temperature increases on Antarctic marine bacteria. 相似文献
17.
气候变暖和大气N沉降是近一、二十年来人们非常关注的全球变化现象,它们所带来的一系列生态问题已成为全球变化研究的重要议题。它们不仅影响地上植被生长和群落组成,还直接或间接地影响土壤微生物过程,而土壤微生物对此做出的响应正是生态系统反馈过程中非常重要的环节。该文分别从气候变化对土壤微生物的影响(土壤微生物量、微生物活动和微生物群落结构)和土壤微生物对气候变化的响应(凋落物分解、养分利用与循环以及养分的固持与流失)两个角度,综述近期土壤微生物对气候变暖和大气N沉降响应与适应的研究进展。气候变暖和大气N沉降对土壤微生物的影响更多地反映在微生物群落的结构和功能上,而土壤微生物量、微生物活动和群落结构的变化又会通过改变凋落物分解、养分利用和C、N循环等重要的土壤生态系统功能和过程做出响应,形成正向或负向反馈,加强或削弱气候变化给整个陆地生态系统带来的影响。然而,到目前为止土壤微生物的响应对陆地生态系统产生的最终结果仍是未决的关键性问题。 相似文献
18.
Soil respiration (Rs) is the largest terrestrial carbon (C) efflux to the atmosphere and is predicted to increase drastically through global warming. However, the responses of Rs to global warming are complicated by the fact that terrestrial plant growth and the subsequent input of plant litter to soil are also altered by ongoing climate change and human activities. Despite a number of experiments established in various ecosystems around the world, it remains a challenge to predict the magnitude and direction of changes in Rs and its temperature sensitivity (Q10) due to litter alteration. We present a meta‐analysis of 100 published studies to examine the responses of Rs and Q10 to manipulated aboveground and belowground litter alterations. We found that 100% aboveground litter addition (double litter) increased Rs by 26.1% (95% confident intervals, 18.4%–33.7%), whereas 100% aboveground litter removal, root removal and litter + root removal reduced Rs by 22.8% (18.5%–27.1%), 34.1% (27.2%–40.9%) and 43.4% (36.6%–50.2%) respectively. Moreover, the effects of aboveground double litter and litter removal on Rs increased with experimental duration, but not those of root removal. Aboveground litter removal marginally increased Q10 by 6.2% (0.2%–12.3%) because of the higher temperature sensitivity of stable C substrate than fresh litter. Estimated from the studies that simultaneously tested the responses of Rs to aboveground litter addition and removal and assuming negligible changes in root‐derived Rs, “priming effect” on average accounted for 7.3% (0.6%–14.0%) of Rs and increased over time. Across the global variation in terrestrial ecosystems, the effects of aboveground litter removal, root removal, litter + root removal on Rs as well as the positive effect of litter removal on Q10 increased with water availability. Our meta‐analysis indicates that priming effects should be considered in predicting Rs to climate change‐induced increases in litterfall. Our analysis also highlights the need to incorporate spatial climate gradient in projecting long‐term Rs responses to litter alterations. 相似文献
19.
Zhongmin Dai Weiqin Su Huaihai Chen Albert Barberán Haochun Zhao Mengjie Yu Lu Yu Philip C. Brookes Christopher W. Schadt Scott X. Chang Jianming Xu 《Global Change Biology》2018,24(8):3452-3461
Long‐term elevated nitrogen (N) input from anthropogenic sources may cause soil acidification and decrease crop yield, yet the response of the belowground microbial community to long‐term N input alone or in combination with phosphorus (P) and potassium (K) is poorly understood. We explored the effect of long‐term N and NPK fertilization on soil bacterial diversity and community composition using meta‐analysis of a global dataset. Nitrogen fertilization decreased soil pH, and increased soil organic carbon (C) and available N contents. Bacterial taxonomic diversity was decreased by N fertilization alone, but was increased by NPK fertilization. The effect of N fertilization on bacterial diversity varied with soil texture and water management, but was independent of crop type or N application rate. Changes in bacterial diversity were positively related to both soil pH and organic C content under N fertilization alone, but only to soil organic C under NPK fertilization. Microbial biomass C decreased with decreasing bacterial diversity under long‐term N fertilization. Nitrogen fertilization increased the relative abundance of Proteobacteria and Actinobacteria, but reduced the abundance of Acidobacteria, consistent with the general life history strategy theory for bacteria. The positive correlation between N application rate and the relative abundance of Actinobacteria indicates that increased N availability favored the growth of Actinobacteria. This first global analysis of long‐term N and NPK fertilization that differentially affects bacterial diversity and community composition provides a reference for nutrient management strategies for maintaining belowground microbial diversity in agro‐ecosystems worldwide. 相似文献
20.
Yogan Monnier Bernard Prévosto Christian Ripert Aude C. Corbani Catherine Fernandez 《植被学杂志》2012,23(2):260-270