Potential Ecological Function Research Articles

Succeed to culture a novel lineage symbiotic bacterium of Mollicutes which widely found in arthropods intestine uncovers the potential double-edged sword ecological function

Succeed to culture a novel lineage symbiotic bacterium of Mollicutes which widely found in arthropods intestine uncovers the potential double-edged sword ecological function

Drought Stress Increases the Complexity of the Bacterial Network in the Rhizosphere and Endosphere of Rice (Oryza sativa L.)

The root microbiota plays a crucial role in assisting the plant host in combating various biotic and abiotic stresses, notably drought, which poses a significant threat to global food security. Despite extensive efforts to understand the shifts in rhizosphere and endosphere bacteriomes, there remains a gap in comprehending how drought stress influences the co-occurring network patterns within these compartments and their ecological functional potentials. To address this gap, a pot experiment was conducted with two treatments: continuous flooding as a control and drought treatment. Bulk soil, rhizosphere, and endosphere samples were collected and subjected to high-throughput sequencing and bioinformatics analysis. The results revealed that drought stress significantly reduced the rice biomass but increased the Shannon diversity index in both the rhizosphere and endosphere bacterial communities with no observable effect on richness across compartments. Additionally, drought treatment markedly altered the community structure and bacterial assemblages in these compartments, resulting in the specific enrichment of Actinobacteriota, Gemmatimonadetes, and Patescibacteria, while Bacteroidetes and Firmicutes were depleted in the rhizosphere and endosphere. Furthermore, drought heightened the complexity of the co-occurring networks and the proportions of positive links across all sampling compartments; this effect was accompanied by an increase in the number of connectors in the bulk soil and rhizosphere, as well as module hubs in the rhizosphere. Functional potential prediction indicated that drought stress significantly altered multiple potential ecological functions across all sampling compartments, particularly enriching functions related to the oxidation of sulfur, manganese, and hydrogen in the bulk soil, while functions associated with iron oxidation were significantly depleted in the rhizosphere. Overall, our results demonstrate that under drought stress, rice may specifically enrich certain bacterial taxa and enhance their positive interactions within its root system to improve adaptation.

Tobacco crop rotation enhances the stability and complexity of microbial networks.

The effects of continuous cropping and rotation cropping, two important tobacco cultivation practices, on soil microbial communities at different stages remain unclear. Different planting patterns have been shown to influence soil physical and chemical properties, which in turn can affect the composition and diversity of soil microbial communities. In order to investigate the impact of different planting methods on soil microbial community structure, we selected two representative planting methods: continuous cropping (tobacco) and rotational cropping (tobacco-maize). These methods were chosen as the focal points of our research to explore the potential effects on soil microbial communities. High-throughput sequencing technology was employed to investigate the structure of soil microbial communities, as well as their relationships with soil environmental factors, by utilizing the 16S rRNA, ITS, and 18S genes. Furthermore, the interaction among microorganisms was explored through the application of the Random Matrix Theory (RMT) molecular ecological network approach. There was no significant difference in α diversity, but significant difference in β diversity based on Jaccard distance test. Compared to continuous cropping, crop rotation significantly increased the abundance of beneficial prokaryotes Verrucomicrobia and Rhodanobacter. These findings indicate that crop rotation promotes the enrichment of Verrucomicrobia and Rhodanobacter in the soil microbial community. AP and NH4-N had a greater effect on the community structure of prokaryotes and fungi in tobacco soil, while only AP had a greater effect on the community structure of protist. Molecular ecological network analysis showed that the network robustness and Cohesion of rotation were significantly higher than that of continuous cropping, indicating that the complexity and stability of molecular ecological networks were higher in the rotational, and the microbial communities cooperated more effectively, and the community structure was more stable. From this point of view, rotational cropping is more conducive to changing the composition of soil microbial community, enhancing the stability of microbial network structure, and enhancing the potential ecological functions in soil.

Effect of salinization on soil properties and mechanisms beneficial to microorganisms in salinized soil remediation–a review

Salinized soil is an important reserved arable land resource in China. The management and utilization of salinized soil can safeguard the current size of arable land and a stable grain yield. Salt accumulation will lead to the deterioration of soil properties, destroy soil production potential and damage soil ecological functions, which in turn will threaten global water and soil resources and food security, and affect sustainable socio-economic development. Microorganisms are important components of salinized soil. Microbial remediation is an important research tool in improving salinized soil and is key to realizing sustainable development of agriculture and the ecosystem. Knowledge about the impact of salinization on soil properties and measures using microorganisms in remediation of salinized soil has grown over time. However, the mechanisms governing these impacts and the ecological principles for microbial remediation are scarce. Thus, it is imperative to summarize the effects of salinization on soil physical, chemical, and microbial properties, and then review the related mechanisms of halophilic and halotolerant microorganisms in salinized soil remediation via direct and indirect pathways. The stability, persistence, and safety of the microbial remediation effect is also highlighted in this review to further promote the application of microbial remediation in salinized soil. The objective of this review is to provide reference and theoretical support for the improvement and utilization of salinized soil.

Response of microbial diversity and function to the degradation of Barkol Saline Lake.

Barkol Lake, a shrinking hypersaline lake situated in the northeast of Xinjiang, China, has experienced the exposure of its riverbed and the gradual drying up of its original sediment due to climate change and human activities, resulting in the formation of alkaline soils. These changes have correspondingly altered the physicochemical characteristics of the surrounding environment. Microorganisms play a crucial role, with special functioning involved in various nutrient cycling and energy transfer in saline lake environments. However, little is known about how the microbial community dynamics and metabolic functions in this shrinking saline lake relate to the degradation process. To address this knowledge gap, a cultivation-independent method of amplicon sequencing was used to identify and analyze the microbial community and its potential ecological functions in the sediment and degraded area. The microbial community diversity was found to be significantly lower in the degraded areas than in the sediment samples. The Pseudomonadota was dominant in Barkol Saline Lake. The abundance of Desulfobacterota and Bacillota in the degraded areas was lower than in the lake sediment, while Pseudomonadota, Acidobacteriota, and Actinobacteriota showed an opposite trend. The βNTI showed that microbial community assembly was primarily associated with deterministic processes in Barkol Saline Lake ecosystems and stochastic processes at the boundary between sediment and degraded areas. Functional predictions showed that sulfur metabolism, particularly sulfate respiration, was much higher in sediment samples than in the degraded areas. Overall, these findings provided a possible perspective for us to understand how microorganisms adapt to extreme environments and their role in saline lakes under environmental change.

Light grazing reduces the abundance of carbon cycling functional genes by decreasing oligotrophs microbes in desert steppe

Understanding the functional genes of microorganisms involved in carbon cycling processes can link microbial community structure to potential ecological functions. However, the effects of grazing on the relationship between carbon cycling functional genes and soil environment need to be further investigated as a global land use activity. A replicated sheep grazing platform was established in Northern China in 2004 with four different stocking rates: no grazing (0 sheep ha−1 month−1), light grazing (0.15 sheep ha−1 month−1), moderate grazing (0.30 sheep ha−1 month−1), and heavy grazing (0.45 sheep ha−1 month−1). To examine the effects of biotic and abiotic factors on microbial species and functional gene abundance, we collected soil samples after 17 years of grazing analyzed for the abundance of microbial communities, the abundance of carbon function genes, plant carbon input and soil environmental factors. We found that light grazing reduced carbon cycling functional genes compared to no grazing (fencing). With increasing grazing intensity, the absolute abundance of functional genes increased. Changes in microbial species abundance were mainly responsible for the changes in the structure of carbon cycling functional genes. Our results emphasize that elucidating how grazing affects the carbon cycling functional genes through the effects of plant carbon inputs and the environment, and the interactions between them, will provide important information for understanding carbon cycling processes in grassland ecosystems.

Differences in archaeal diversity and potential ecological functions between saline and hypersaline lakes on Qinghai-Tibet Plateau were driven by multiple environmental and non-environmental factors beyond the salinity

BackgroundSaline lakes are home to various archaea that play special and crucial roles in the global biogeochemical cycle. The Qinghai-Tibet Plateau hosts a large number of lakes with diverse salinity ranging from 0.1 to over 400 g/L, harboring complex and diverse archaea. To the best of our knowledge, the formation mechanisms and potential ecological roles of archaea in Qinghai-Tibetan Plateau saline lakes remain largely unknown.ResultsUsing High-throughput Illumina sequencing, we uncovered the vastly distinct archaea communities between two typical saline lakes with significant salinity differences on the Qinghai Tibet Plateau (Qinghai saline lake and Chaka hypersaline lake) and suggested archaea played different important roles in methanogenesis-related and nitrate reduction-related functions of these two lakes, respectively. Rather than the individual effect of salinity, the composite effect of salinity with diverse environmental parameters (e.g., temperature, chlorophyll a, total nitrogen, and total phosphorus) dominated the explanation of the variations in archaeal community structure in different habitats. Based on the network analysis, we further found the correlations between dominant archaeal OTUs were tight but significantly different between the two habitats, implying that archaeal interactions may also largely determine the shape of archaeal communities.ConclusionThe present study improved our understanding of the structure and function of archaea in different saline lakes on the Qinghai-Tibet Plateau and provided a new perspective on the mechanisms underlying shaping their communities.

The "elongate chelicera problem": A virtual approach in an extinct pterygotid sea scorpion from a 3D kinematic point of view.

Chelicerae, distinctive feeding appendages in chelicerates, such as spiders, scorpions, or horseshoe crabs, can be classified based on their orientation relative to the body axis simplified as either orthognathous (parallel) or labidognathous (inclined), exhibiting considerable diversity across various taxa. Among extinct chelicerates, sea scorpions belonging to the Pterygotidae represent the only chelicerates possessing markedly elongated chelicerae relative to body length. Despite various hypotheses regarding the potential ecological functions and feeding movements of these structures, no comprehensive 3D kinematic investigation has been conducted yet to test these ideas. In this study, we generated a comprehensive 3D model of the pterygotid Acutiramus, making the elongated right chelicera movable by equipping it with virtual joint axes for conducting Range of Motion analyses. Due to the absence in the fossil record of a clear indication of the chelicerae orientation and their potential lateral or ventral movements (vertical or horizontal insertion of joint axis 1), we explored the Range of Motion analyses under four distinct kinematic settings with two orientation modes (euthygnathous, klinogathous) analogous to the terminology of the terrestrial relatives. The most plausible kinematic setting involved euthygnathous chelicerae being folded ventrally over a horizontal joint axis. This configuration positioned the chelicera closest to the oral opening. Concerning the maximum excursion angle, our analysis revealed that the chela could open up to 70°, while it could be retracted against the basal element to a maximum of 145°. The maximum excursion in the proximal joint varied between 55° and 120° based on the insertion and orientation. Our findings underscore the utility of applying 3D kinematics to fossilized arthropods for addressing inquiries on functional ecology such as prey capture and handling, enabling insights into their possible behavioral patterns. Pterygotidae likely captured and processed their prey using the chelicerae, subsequently transporting it to the oral opening with the assistance of other prosomal appendages.

Community Structure, Drivers, and Potential Functions of Different Lifestyle Viruses in Chaohu Lake.

Viruses, as the most prolific entities on Earth, constitute significant ecological groups within freshwater lakes, exerting pivotal ecological roles. In this study, we selected Chaohu Lake, a representative eutrophic freshwater lake in China, as our research site to explore the community distribution, driving mechanisms, and potential ecological functions of diverse viral communities, the intricate virus-host interaction systems, and the overarching influence of viruses on global biogeochemical cycling.

Comparison of Rhizosphere Bacterial Communities of Pinus squamata, a Plant Species with Extremely Small Populations (PSESP) in Different Conservation Sites.

Pinus squamata is one of the most threatened conifer species in the world. It is endemic to northeastern Yunnan Province, China, and has been prioritized as a Plant Species with Extremely Small Populations (PSESP). The integrated study of soil properties and rhizosphere bacteria can assist conservation to understand the required conditions for the protection and survival of rare and endangered species. However, differences between the rhizospheric bacterial communities found in the soil surrounding P. squamata at different conservation sites remain unclear. In this study, Samples were collected from wild, ex situ, and reintroduced sites. Bacterial communities in different conservation sites of P. squamata rhizosphere soils were compared using Illumina sequencing. The soil physicochemical properties were determined, the relationships between the bacterial communities and soil physicochemical factors were analyzed, and the potential bacterial ecological functions were predicted. The reintroduced site Qiaojia (RQ) had the highest richness and diversity of bacterial community. Actinobacteria, Proteobacteria, and Acidobacteriota were the dominant phyla, and Bradyrhizobium, Mycobacterium, Acidothermus were the most abundant genera. Samples were scattered (R = 0.93, p = 0.001), indicating significant difference between the different conservation sites. The abundance of Mycobacterium differed between sites (0.01 < p ≤ 0.05), and the relative abundances of Bradyrhizobium and Acidothermus differed significantly among different sites (0.001 < p ≤ 0.01). Soil total potassium (TK) and available nitrogen (AN) were the main factors driving bacterial community at the phylum level (0.01 < p ≤ 0.05). This study generated the first insights into the diversity, compositions, and potential functions of bacterial communities associated with the rhizosphere soils of P. squamata in different conservation sites and provides a foundation to assess the effect of conservation based on bacterial diversity and plant growth-promoting rhizobacteria (PGPR) to guide future research into the conservation of P. squamata.

Comparative metabarcoding and biodiversity of gut-associated fungal assemblages of Dendroctonus species (Curculionidae: Scolytinae).

The genus Dendroctonus is a Holarctic taxon composed of 21 nominal species; some of these species are well known in the world as disturbance agents of forest ecosystems. Under the bark of the host tree, these insects are involved in complex and dynamic associations with phoretic ectosymbiotic and endosymbiotic communities. Unlike filamentous fungi and bacteria, the ecological role of yeasts in the bark beetle holobiont is poorly understood, though yeasts were the first group to be recorded as microbial symbionts of these beetles. Our aim was characterize and compare the gut fungal assemblages associated to 14 species of Dendroctonus using the internal transcribed spacer 2 (ITS2) region. A total of 615,542 sequences were recovered yielding 248 fungal amplicon sequence variants (ASVs). The fungal diversity was represented by 4 phyla, 16 classes, 34 orders, 54 families, and 71 genera with different relative abundances among Dendroctonus species. The α-diversity consisted of 32 genera of yeasts and 39 genera of filamentous fungi. An analysis of β-diversity indicated differences in the composition of the gut fungal assemblages among bark beetle species, with differences in species and phylogenetic diversity. A common core mycobiome was recognized at the genus level, integrated mainly by Candida present in all bark beetles, Nakazawaea, Cladosporium, Ogataea, and Yamadazyma. The bipartite networks confirmed that these fungal genera showed a strong association between beetle species and dominant fungi, which are key to maintaining the structure and stability of the fungal community. The functional variation in the trophic structure was identified among libraries and species, with pathotroph-saprotroph-symbiotroph represented at the highest frequency, followed by saprotroph-symbiotroph, and saprotroph only. The overall network suggested that yeast and fungal ASVs in the gut of these beetles showed positive and negative associations among them. This study outlines a mycobiome associated with Dendroctonus nutrition and provides a starting point for future in vitro and omics approaches addressing potential ecological functions and interactions among fungal assemblages and beetle hosts.

Nature-Based Management of Lawns—Enhancing Biodiversity in Urban Green Infrastructure

Urban green areas have multifunctional benefits that may mitigate unfavorable health and ecological effects. Green areas represent important biodiversity hideouts in anthropogenic regions. Lawns are the most common elements of urban greenery, covering a considerable number of green areas in cities. The aim of this analysis was to gain knowledge on urban greenery and elaborate recommendations related to management that favors grass lawn biodiversity. The established working hypothesis is that the limited intensity of management in urban grass areas is reflected in the modification of their species composition, as well as their potential ecological functions. An experiment on the management of city lawns was conducted in 2010 (still ongoing). There are three lawn variants under different management methods: ornamental, city, and permaculture lawns. Vegetation was assessed using the method of phytocoenological relevés. The coverage values of the individual plant species were processed using multidimensional analysis of ecological data. The results showed that human decisions and activities affected the species composition of these grassy areas. There were 46 plant taxa found during the monitoring: 12 in ornamental lawn variants, 24 in city lawn variants, and 31 in permaculture lawn variants. Permaculture lawns with extensive management represent the most environmentally friendly variant with respect to biodiversity and soil moisture content. However, changes in species composition have raised questions regarding the extent to which they may perform other ecosystem functions. Increasing the intensity of lawn management has resulted in lower plant diversity. Extensive management alters the aesthetic value of lawns and creates spaces for species that may spread in urban environments.

Comparison of distinctive diversities, co-occurrence patterns and potential ecological functions of microbial communities in heterogeneous soil areas in typical subtropical forests, southeast China

Although microbes are crucial in ecological cycling in forest soil, the response of the network structure and ecological functions of these microorganisms to soil heterogeneity remains elusive. Here, we analyzed the composition and co-occurrence network patterns of microorganisms in heterogeneous soil areas and evaluated their potential ecological functions, taking the scenic area (SA) and nature reserve (NR) of Wuyishan National Park as examples. Our results showed that the soil properties of SA and NR could almost be clustered separately, and soil heterogeneity between them has been found. Prokaryotic communities in both areas were also divided and showed higher similarities individually than those of eukaryotes. The prokaryotic community composition in both areas was mainly affected by pH and ammonia, while the eukaryotic community composition was mainly affected by total carbon and the carbon to nitrogen ratio. Both the microbial network and ecological function network in SA were more complex than those of NR, while those of NR were more stable than those of SA. The keystone taxa of pro- and eukaryotes with important ecological functions were enriched in SA and NR, respectively. Moreover, significant discrepancies between SA and NR were found in the prokaryotic functions related to nitrogen cycling, sulfur cycling, and compound degradation. Our study illuminated that the soil heterogeneity in subtropical areas changed microbial community diversity, interaction patterns, and keystone taxa composition, and might further affect their ecological functions.

Diversity and assembly patterns of mangrove rhizosphere mycobiome along the Coast of Gazi Bay and Mida Creek in Kenya.

Fungi are among key actors in the biogeochemical processes occurring in mangrove ecosystems. In this study, we investigated the changes of fungal communities in selected mangrove species by exploring differences in diversity, structure and the degree of ecological rearrangement occurring within the rhizospheres of four mangrove species (Sonneratia alba, Rhizophora mucronata, Ceriops tagal and Avicennia marina) at Gazi Bay and Mida Creek in Kenya. Alpha diversity investigation revealed that there were no significant differences in species diversity between the same mangrove species in the different sites. Rather, significant differences were observed in fungal richness for some of the mangrove species. Chemical parameters of the mangrove sediment significantly correlated with fungal alpha diversity and inversely with richness. The fungal community structure was significantly differentiated by mangrove species, geographical location and chemical parameters. Taxonomic analysis revealed that 96% of the amplicon sequence variants belonged to the Phylum Ascomycota, followed by Basidiomycota (3%). Predictive FUNGuild and co-occurrence network analysis revealed that the fungal communities in Gazi Bay were metabolically more diverse compared to those of Mida Creek. Overall, our results demonstrate that anthropogenic activities influenced fungal richness, community assembly and their potential ecological functions in the mangrove ecosystems investigated.

Abundant and Rare Microbial Subcommunities in Soda Lake Nukhe-Nur (Barguzin Depression, Russia)

In this study, we first investigated the composition of microbial communities of abundant, intermediate and rare subcommunities in soda Lake Nukhe-Nur (the Barguzin Basin) using Illumina MiSeq high-throughput sequencing. The results showed that abundant subcommunities mainly consisted of Pseudomonadota, Cyanobacteriota, Bacteroidota и Bacillota. In contrast, the rare subcommunities in the microbial mats were mainly composed of Pseudomonadota, Cyanobacteriota, Bacillota, Deinococcota, Gemmatimonadota, Bacteroidota, Actinobacteriota, Kiritimatiellaeota. In the rare subcommunity of the bottom sediments, Euryarchaeota, Actinobacteriota, Pseudomonadota, Bacillota, Bacteroidota, Chloroflexota, Gemmatimonadota, Verrucomicrobiota, Epsilonbacteraeota, and Deinococcota were found. However, the dominant phyla of the abundant subcommunity were also found in the intermediate and rare subcommunities. The predictive analysis of the microbial ecological function has revealed a broad potential diversity of metabolic pathways in the abundant, intermediate, and rare subcommunities of microbial mats and bottom sediments in Lake Nukhe-Nur. In soda lakes, rare subcommunities may play a greater role in the decomposition of organic matter than do abundant subcommunities. Overall, this study provides a better understanding of the microbial community structure and potential ecological functions of abundant and rare subcommunities in soda lakes ecosystems. The identified rare taxa open new opportunities for ecological, taxonomic, and genomic discoveries in Barguzin soda lakes.

Differential Responses of Bacterial Communities in Rhizosphere and Bulk Soils of Cotton to Long-Term Amelioration Practices Based on Freezing Saline Water Irrigation and Plastic Mulching in a Coastal Saline Soil

Soil amelioration in coastal saline areas plays an important role in alleviating land resource shortages, improving regional ecological environments, ensuring food security, and promoting economic development. Plastic mulching (M) and the combination of freezing saline water irrigation and plastic mulching (WIM) are successful amelioration practices that dramatically reduce the salinity of surface soil and facilitate plant growth in coastal saline soil. However, the bacterial responses that are closely related to these amelioration practices in coastal saline soil remain poorly understood. In this study, bacterial richness and diversity, community composition, and potential ecological functions in the rhizosphere and bulk soils of cotton in M and WIM treatments, along with a control treatment, were investigated using high-throughput sequencing in a coastal saline field. The results showed that both the M and WIM treatments increased bacterial richness and alpha diversity, which were in general significantly higher in bulk soil than in rhizosphere soil. Non-metric multidimensional scaling and the Bray–Curtis dissimilarity analysis revealed that the bacterial community in rhizosphere soil was assembled far from those in the control and bulk soils and behaved more specifically in rhizosphere soil than in bulk soil. The relative abundances of most of the dominant phyla showed opposite trends of variation in bulk and rhizosphere soils compared to those in control soil in both M and WIM treatments; in particular, the specific bacterial groups of Proteobacteria and Actinobacteria decreased in bulk soil but significantly increased in rhizosphere soil. Functional groups of chemoheterotrophy, aerobic chemoheterotrophy, and nitrate reduction were predominant in rhizosphere rather than bulk soil, according to the Functional Annotation of Prokaryotic Taxa. These findings improve the understanding of the mechanism of bacterial responses to amelioration practices M and WIM in coastal saline soils and provide valuable information for the development of amelioration techniques based on agricultural practices and soil microbiome to enhance plants’ adaptability to saline soil in the future.

Heavy metal contamination impacts the structure and co-occurrence patterns of bacterial communities in agricultural soils.

Heavy metal (HM) contamination caused by mining and smelting activities can be harmful to soil microbiota, which are highly sensitive to HM stress. Here, we explore the effects of HM contamination on the taxonomic composition, predicted function, and co-occurrence patterns of soil bacterial communities in two agricultural fields with contrasting levels of soil HMs (i.e., contaminated and uncontaminated natural areas). Our results indicate that HM contamination does not significantly influence soil bacterial α diversity but changes the bacterial community composition by enriching the phyla Gemmatimonadetes, Planctomycetes, and Parcubacteria and reducing the relative abundance of Actinobacteria. Our results further demonstrate that HM contamination can strengthen the complexity and modularity of the bacterial co-occurrence network but weaken positive interactions between keystone taxa, leading to the gradual disappearance of some taxa that originally played an important role in healthy soil, thereby possibly reducing the resistance of bacterial communities to HM toxicity. The predicted functions of bacterial communities are related to membrane transport, amino acid metabolism, energy metabolism, and carbohydrate metabolism. Among these, functions related to HM detoxification and antioxidation are enriched in uncontaminated soils, while HM contamination enriches functions related to metal resistance. This study demonstrated that microorganisms adapt to the stress of HM pollution by adjusting their composition and enhancing their network complexity and potential ecological functions.

Soil bacterial communities are more sensitive to short-term nitrogen deposition than fungal communities in subtropical Chinese fir forests

The increasing rate of atmospheric nitrogen (N) deposition seriously affects the structure and function of ecosystems. Although soil microorganisms play a crucial role in ecosystem carbon (C) and nutrient cycling, the impact of N deposition on soil microbial communities in subtropical forest ecosystems is unclear. Here, we selected the subtropical Chinese fir (Cunninghamia lanceolata) forest as the research object and conducted simulated N deposition experiments with different levels of N deposition (0 kg N ha−1 yr−1,50 kg N ha−1 yr−1, 100 kg N ha−1 yr−1, and 200 kg N ha−1 yr−1, respectively) to explore the response of soil nutrients, soil microbial community structure, and potential ecological functions to short-term N deposition. We found that the bacterial richness Chao1 index and phylogenetic diversity PD_whole_tree decreased with the N deposition level approximately 13 % −16 % under MN and HN treatment. N deposition significantly altered the composition of soil bacterial communities (P < 0.05), but the responses of different taxa to N deposition were inconsistent at different stages of growing season. N deposition treatment significantly increased the relative abundance of Actinobacteria at both beginning of growing season (BGS) and end of growing season (EGS), decreased the relative abundances of Planctomycetes at BGS, and decreased the relative abundances of Elusimicrobia and Cyanobacteria at both BGS and EGS. Non-metric multidimensional scaling (NMDS) and Anosim (Analysis of similarities) analyses showed that the bacterial communities were clearly distinguished among treatments at both BGS and EGS. However, N deposition had a relatively small impact on fungal communities, only altering the fungal community structure at BGS. The impact of N deposition on soil microbial communities was mainly induced by the alteration in soil water content (SWC), pH, NO3–-N, and available nitrogen (AN). Both bacterial and fungal communities exhibit seasonal community dynamics, while the interaction of N deposition and season was mainly reflected in the impact on bacterial communities. Our research not only provides research ideas for the potential impact of nitrogen deposition on subtropical forest ecosystems in the short term, but also provides a theoretical basis for future scientific management and regulation of forestry, microorganisms, and sustainable management of Chinese fir plantations.

From small waterbodies to large multi-service providers: Assessing their ecological multifunctionality for terrestrial birds in Mediterranean agroecosystems

Agricultural intensification has caused a rapid loss of singular landscape elements worldwide, such as farmland ponds, hedgerows and field margins, leading to a steep decline in farmland bird populations. Farmland ponds and traditional small waterbodies (SWB) have been recently reported to support species-rich bird communities at landscape scale in several agroecosystems. However, a comprehensive assessment on the potential ecological functions provided by SWB to terrestrial birds has been never conducted. Here, we used data from breeding bird surveys at 39 traditional SWB to highlight the variety and magnitude of ecological functions provided to terrestrial birds. These SWB belonged to three different structural types and were spread along an environmental gradient in Mediterranean agroecosystems from southeastern Spain. We identified up to six cross-system services benefiting different functional guilds of terrestrial birds. Apart from to the well-documented supply of drinking water, traditional SWB delivered other ecologically relevant and commonly overlooked services to terrestrial birds, such as the provision of bathing sites, essential food resources (e.g., emerging insects), nest-building material and suitable adjacent perches for territorial display or thermoregulation. Structural and environmental variables at waterbody scale played an important role as determinants of the recorded ecological functions. Importantly, most of these ecological functions were evenly observed across the three types of traditional SWB, thus supporting the key role of these singular landscape elements for bird conservation regardless their structural attributes. Agri-environment schemes and farmland biodiversity conservation strategies should account for the ecological multifunctionality of traditional SWB by ensuring the protection and nature-friendly management of these valuable habitats, as well as by promoting the diversity of microhabitats at SWB scale.

Genome Analysis and Potential Ecological Functions of Members of the Genus Ensifer from Subsurface Environments and Description of Ensifer oleiphilus sp. nov.

The current work deals with genomic analysis, possible ecological functions, and biotechnological potential of two bacterial strains, HO-A22T and SHC 2-14, isolated from unique subsurface environments, the Cheremukhovskoe oil field (Tatarstan, Russia) and nitrate- and radionuclide-contaminated groundwater (Tomsk region, Russia), respectively. New isolates were characterized using polyphasic taxonomy approaches and genomic analysis. The genomes of the strains HO-A22T and SHC 2-14 contain the genes involved in nitrate reduction, hydrocarbon degradation, extracellular polysaccharide synthesis, and heavy metal detoxification, confirming the potential for their application in various environmental biotechnologies. Genomic data were confirmed by cultivation studies. Both strains were found to be neutrophilic, chemoorganotrophic, facultatively anaerobic bacteria, growing at 15-33 °C and 0-1.6% NaCl (w/v). The 16S rRNA gene sequences of the strains were similar to those of the type strains of the genus Ensifer (99.0-100.0%). Nevertheless, genomic characteristics of strain HO-A22T were below the thresholds for species delineation: the calculated average nucleotide identity (ANI) values were 83.7-92.4% (<95%), and digital DNA-DNA hybridization (dDDH) values were within the range of 25.4-45.9% (<70%), which supported our conclusion that HO-A22T (=VKM B-3646T = KCTC 92427T) represented a novel species of the genus Ensifer, with the proposed name Ensifer oleiphilus sp. nov. Strain SHC 2-14 was assigned to the species 'Ensifer canadensis', which has not been validly published. This study expanded the knowledge about the phenotypic diversity among members of the genus Ensifer and its potential for the biotechnologies of oil recovery and radionuclide pollution treatment.