Differences In Community Structure Research Articles

Unveiling the Virome of Wild Birds: Exploring CRESS-DNA Viral Dark Matter.

Amid global health concerns and the constant threat of zoonotic diseases, this study delves into the diversity of circular replicase-encoding single-stranded DNA (CRESS-DNA) viruses within Chinese wild bird populations. Employing viral metagenomics to tackle the challenge of "viral dark matter," the research collected and analyzed 3,404 cloacal swab specimens across 26 bird families. Metagenomic analysis uncovered a rich viral landscape, with 67.48% of reads classified as viral dark matter, spanning multiple taxonomic levels. Notably, certain viral families exhibited host-specific abundance patterns, with Galliformes displaying the highest diversity. Diversity analysis categorized samples into distinct groups, revealing significant differences in viral community structure, particularly noting higher diversity in terrestrial birds compared to songbirds and unique diversity in migratory birds versus perching birds. The identification of ten novel Circoviridae viruses, seven Smacoviridae viruses, and 167 Genomoviridae viruses, along with 100 unclassified CRESS-DNA viruses, underscores the expansion of knowledge on avian-associated circular DNA viruses. Phylogenetic and structural analyses of Rep proteins offered insights into evolutionary relationships and potential functional variations among CRESS-DNA viruses. In conclusion, this study significantly enhances our understanding of the avian virome, shedding light on the intricate relationships between viral communities and host characteristics in Chinese wild bird populations. The diverse array of CRESS-DNA viruses discovered opens avenues for future research into viral evolution, spread factors, and potential ecosystem impacts.

Ecological characteristics of tall fescue and spatially organized communities: Their contribution to mitigating cadmium damage

The threat of cadmium (Cd) stress to agricultural soil environments, as well as their productivity attracting growing global interest. Tall fescue (Festuca arundinacea Schreb.) is a strong candidate for the remediation of heavy metals in soil. However, the joint analysis of Cd tolerance, physiological responses, and multifaceted plant microbiomes in tall fescue fields has not been extensively researched. Therefore, this study employed microbial sequencing (i.e., 16S and ITS sequencing) to investigate the differences in microbial community structure among various plant compartments of Cd-resistant tall fescue (cv. ‘Arid3′) and Cd-sensitive tall fescue (cv. ‘Barrington’). Furthermore, we examined the mechanism of resistance to Cd by introducing three different bacteria and a fungus that were isolated from the ‘Arid3′ rhizosheath soil. It highlighted the potential application of enriched taxa such as Delftia, Novosphingobium, Cupriavidus and Torula in enhancing the activity of antioxidant defense systems, increasing the production of osmotic regulatory substances, and stimulating the expression of Cd-resistance genes. This ultimately promoted plant growth and enhanced phytoremediation efficiency. This study shed light on the response mechanism of the tall fescue microbiome to Cd stress and underscored the potential of tall fescue-microbe co-culture in the remediation of heavy metal-contaminated areas.

Characteristics of soil viral communities in Cunninghamia lanceolata plantations with different stand ages.

We investigated the dynamics of soil viral community in Cunninghamia lanceolata plantations with different stand ages (8, 21, 27, and 40 years old) in a subtropical region. The viral metagenomics and bioinformatics analysis were used to analyze the compositional and functional differences of soil viral communities across different stand ages, and to explore the environmental driving factors. The results showed that tailed phages dominated soil viral community in subtropical C. lanceolata plantations, with the highest proportion of Siphoviridae (19.6%-39.5%). There was significant difference in soil viral community structure among different stand ages, with the main driving factors being electrical conductance and available phosphorus. The metabolic functional genes encoded by viruses exhibited higher relative abundance. The α-diversity of soil viral function in mature C. lanceolata plantations was higher than other stands. There were significant differences in soil viral functional structure among different stand ages, which were mainly driven by ammonium nitrogen. During the development of C. lanceolata plantations, auxiliary metabolic genes encoded by virus related to nitrogen and phosphorus may regulate the metabolism of host microorganisms, thereby potentially impacting biogeochemical cycling of these elements.

PSV-12 Evaluating the effect of lyoprotectants in preserving community structure and bacterial viability in the lyophilized fecal community of pigs

Abstract Fecal microbiota transplantation (FMT) stands as a potential method for enhancing pig health. FMT has progressed from the basic delivery of fresh stool, to lyophilized preparations which is beneficial for sample storage, but can damage bacterial cells. This has necessitated the need for lyoprotectants to preserve bacterial viability. However, the ideal lyoprotectant for retaining community structure and viability remains unclear. Furthermore, DNA-based microbial profiling methods such as 16S rRNA and metagenomics sequencing do not distinguish live and dead bacteria, prompting the need for other methods of distinguishing live and dead members of the bacterial community after lyophilization. PMA-seq (propidium monoazide treatment followed by 16S rRNA gene amplicon sequencing) has been shown to differentiate between live and dead bacteria in microbial communities. To refine FMT in pigs, we sought to ascertain the impact of four lyoprotectants on bacterial viability and fecal microbiome structure. Fecal samples from six pigs were treated with mannitol, maltodextrin, trehalose, maltodextrin-trehalose mix (2.5% each) as lyoprotectants or left untreated. Lyophilized fecal samples underwent PMA treatment prior to 16S rRNA sequencing to capture the active community, and total and viable bacterial cells number were quantified. One-way ANOVA was used to analyze total and viable bacterial cells, and richness, while PERMANOVA was used to compare beta diversity. Results revealed no initial differences in total, viable bacteria, or community structure (P > 0.05). However, untreated, and mannitol-treated groups showed significantly reduced total and viable bacterial cells post-lyophilization (P < 0.01), unlike the other lyoprotectants (P > 0.05). Mannitol and the untreated group also displayed decreased richness and beta diversity shifts (P < 0.05). Overall, lyophilization with mannitol or no lyoprotectant notably impacted pig fecal microbiota community structure, while maltodextrin, trehalose, and maltodextrin-trehalose effectively preserved bacterial viability and structure.

Tree species-mediated soil properties shape soil fauna community structure more strongly in the soil layer: Evidence from a common garden experiment

Soil fauna plays a crucial role in the soil biogeochemical cycles of forest ecosystems, with tree species composition regulating their diversity and functionality through alterations in habitat conditions and nutrient availability. However, identifying the impacts of tree species on soil faunal communities remains challenging due to the difficulty in distinguishing the effects of tree species-induced habitat changes from those of historical environmental conditions. Here, we conducted a field study in a common garden established in 2015, with consistent climate, soil, and land-use conditions to clarify the response of the soil faunal community to changes in tree species. After 5 years of plantation growth, we evaluated the differences in tree species identities and soil faunal community structures between the litter and soil layers in four closed-canopy broadleaf forests (Cinnamomum septentrionale, Cinnamomum camphora, Cinnamomum longepaniculatum and Toona sinensis). We found that the soil faunal communities differed significantly among the four broad-leaved tree species, with 18.7 % being dominated by Collembola and 67.2 % by Acari, with a relatively high proportion of microbivores (65.5 %). Compared with that of the other stands, the C. longepaniculatum stand had the most notable differences in taxa composition, while the T. sinensis stand exhibited the greatest soil biological quality, with a QBS value 1.25 times greater than that of other stands. The greatest total soil faunal abundance was observed in C. camphora, and this high abundance was due to a greater proportion of microbivores (75.4 %), whereas the detritivores, herbivores, and predators exhibited greater abundance in T. sinensis than in the other stands due to the high-quality litter input (low C/P and C/N ratios) and low tree biomass. The distribution of soil fauna across the habitat layers was significantly influenced by tree species changes, with the most pronounced differences occurring in the soil layer rather than in the litter layer. Finally, soil properties, rather than litter and plant conditions, were the primary factors explaining interspecific variations in total abundance and total diversity of the soil fauna and the QBS index, accounting for 61.6 %, 71.7 %, and 34.4 % of the variation, respectively. The results from the common garden experiment suggest that the change in the soil faunal community due to tree species identity was greater in the soil layer than in the litter layer, with the crucial determinant being tree-species-mediated soil properties. These insights enhance our understanding of the effect of tree species on soil faunal communities, which is essential for biodiversity conservation in artificial forests and for guiding tree species selection.

Metacommunity structures of dormant and active zooplankton in two distant mediterranean regions

Abstract Temporary ponds are small‐sized limnic systems that dry periodically. The length of the wet phase defines the hydroregime and determines community assembly in temporary ponds. Zooplankton species have adapted to desiccation by adopting some dormant strategies, such as the formation of resting stages. Hatching from resting stages is a source of recolonization after drought events and the composition of hatching taxa is also influenced by hydroregime. We compared metacommunity structure and composition of the dormant sub‐community (resting stages); the pioneer active sub‐community (fauna present immediately after inundation of ponds); and the cumulative active sub‐community (fauna present at the initial, middle and final phases of hydroperiod) in a set of temporary ponds with semipermanent and seasonal hydroregimes in two areas with mediterranean climate: central Chile and eastern Spain. We aimed to determine the influence of hydroregime and identify whether metacommunity patterns are consistent between regions sharing a mediterranean climate. We selected five semipermanent and five seasonal ponds in each region to sample sediments and active zooplankton sub‐communities. By combining hatching experiments from the sediments with direct counts of active zooplankton from the field samples, we gathered data on both dormant and active sub‐communities to build unweighted bipartite networks of species occurrences in each pond. The obtained networks were analysed to determine seasonal trends in structural features of the metacommunities (diversity, nestedness and modularity) and their relation to hydroregime (semipermanent and seasonal) and geographical location (Chile and Spain). We observed consistent differences in community structure when comparing sub‐communities at different successional stages (dormant, pioneer active and cumulative active) and with different hydroregimes (semipermanent vs. seasonal). Both α‐ and γ‐diversity showed a consistent trend, being highest in cumulative active sub‐communities and lowest in dormant ones, and were consistently higher in seasonal ponds, regardless of the region. In addition, β‐diversity was higher in the pioneer active sub‐community in both regions, with no significant differences between hydroregimes. The species composition of cumulative active sub‐communities were less heterogeneous than that of the pioneer and dormant ones. No consistent patterns were found in modularity and nestedness values across sub‐communities and hydroregimes. In agreement with our hypotheses, we observed a gradual accumulation of taxa as well as community homogenization over time in both regions. Contrary to our expectations, hydroregime did not affect these patterns and, surprisingly, shorter hydroperiods exhibited higher regional diversity. Our results suggest that hydroregime as a single variable does not have a strong explanatory power for metacommunity assembly of temporary ponds. Therefore, a more comprehensive theory is needed to anticipate the effects of the upcoming hydroperiod shortening.

Deciphering the differences of bacterial communities between high- and low-productive wheat fields using high-throughput sequencing.

Microbial communities have been demonstrated to be essential for healthy and productive soil ecosystems. However, an understanding of the relationship between soil microbial community and soil productivity levels is remarkably limited. In this study, bulk soil (BS), rhizosphere soil (RS), and root (R) samples from the historical high-productive (H) and low-productive (L) soil types of wheat in Hebei province of China were collected and analyzed by high-throughput sequencing. The study highlighted the richness, diversity, and structure of bacterial communities, along with the correlation networks among different bacterial genera. Significant differences in the bacterial community structure between samples of different soil types were observed. Compared with the low-productive soil type, the bacterial communities of samples from the high-productive soil type possessed high species richness, low species diversity, complex and stable networks, and a higher relative abundance of beneficial microbes, such as Pseudoxanthomonas, unclassified Vicinamibacteraceae, Lysobacter, Massilia, Pseudomonas, and Bacillus. Further analysis indicated that the differences were mainly driven by soil organic matter (SOM), available nitrogen (AN), and electrical conductivity (EC). Overall, the soil bacterial community is an important factor affecting soil health and crop production, which provides a theoretical basis for the targeted regulation of microbes in low-productivity soil types.

Towards a Standardized Operating Procedure for eDNA‐Based Biomonitoring in Coastal Marine Salmon Aquaculture

ABSTRACTThe marine aquaculture industry and regulators are in the process of implementing environmental DNA (eDNA) metabarcoding of microbial communities for compliance monitoring. This requires standardization of sampling, laboratory, and data analysis protocols. Towards this goal, we in this study completed two further milestones using samples collected from two Scottish salmon farms: (i) We tested the effect of using two different PCR protocols (i.e., different DNA polymerases, master mixes, and annealing temperatures), which are frequently being used in eDNA biomonitoring of aquaculture installations, for the amplification of the taxonomic marker gene (V3‐V4 hypervariable region of the bacterial 16S rRNA gene). (ii) We quantified sampling background noise obtained from eDNA samples and statistically compared results with the sampling bias observed in macrofaunal samples from the same source sediments. We detected differences in bacterial community structures resulting from the performance of different PCR protocols, profoundly influencing the interpretation of biomonitoring results. Furthermore, we found that sampling‐induced errors for eDNA samples were similar to errors for macrofaunal samples collected according to compliance monitoring protocol (~25% variability in both cases). Finally, we showed that within‐grab variances of microbial community structures were in the same order of magnitude (less than 10× difference in all cases) as the one obtained from replicate grabs collected from the same locale (impact category). Based on our findings, we suggest using a consistent PCR protocol for biomonitoring efforts to improve the comparability of results, especially when different service providers are conducting the biomonitoring. We propose a sampling scheme to be considered in eDNA biomonitoring that includes taking three replicate grabs at each locale, with one replicate sample from each grab. This minimizes sampling‐induced errors and makes upcoming eDNA‐based monitoring results comparable with previous compliance monitoring results obtained from macrofaunal data.

Comparative analysis of fecal microbiota between diarrhea and non-diarrhea piglets reveals biomarkers of gut microbiota associated with diarrhea

Diarrhea poses a significant threat to the health and well-being of weaned piglets, leading to substantial morbidity and mortality and economic loss in the pig industry. However, the structural characteristics of the gut microbiota and the key genera associated with early diarrhea in piglets within large-scale production systems are poorly understood. To identify the biomarkers of gut microbiota associated with diarrhea in piglets, we collected 250 fecal samples from 3 large-scale farms as discovery cohorts to investigate the differences in the microbial community structure and the specific genera alteration between the healthy piglets and diarrhea piglets. The Chao1 and ACE indices were obviously lower in the diarrhea piglets compared to healthy ones (P < 0.01). Principal coordinate analysis showed significant differences in the distance matrix of gut microbiota between the healthy and diarrhea piglets. Eighty-five genera were differentially enriched between healthy and diarrhea piglets. Notably, Treponema, Sphaerochaeta, Escherichia-Shigella, Slackia, and Staphylococcus were identified as potential biomarkers of diarrhea susceptibility; Clostridium sensu stricto 1, Prevotella_9, Olsenella, Dorea, and Lachnospiraceae NK4A136 group were found to be beneficial for maintaining the intestinal homeostasis. These differentially enriched genera of healthy and diarrhea piglets were further confirmed in the validation cohort. These findings provide a theoretical basis for the diagnosis and intervention of diarrhea in weaned piglets.

Coral mucus promotes the carbon metabolic potency of microorganisms in the coral reef ecosystem

AbstractCoral mucus, teeming with organic matter, releases nutrients and microorganisms, affecting element cycling and microbial communities in coral reefs. While terrestrial ecosystems exhibit well‐studied priming effects from root exudates, the influence of mucus in marine environments, particularly in coral reefs, remains underexplored. We hypothesize that coral mucus, through its nutrients and microbes, stimulates the surrounding microorganisms, regulating carbon metabolism and thus contributing to high coral reef productivity. Initially, natural samples (Acropora pruinosa mucus, seawater, and sediment) were collected for metagenomic assessment of microbial communities and functions. Results showed significant differences in microbial diversity, community structures, co‐occurrence modes, and unique functions among mucus, seawater, and sediment. Subsequent laboratory experiments demonstrated mucus's substantial influence on surrounding microorganisms. Analyses, including 16S rRNA sequencing and Eco‐plate results, revealed that mucus regulates microbial composition and activities. Quantitative gene‐chip analysis showed significant increase in the functional genes related to carbon fixation (e.g., the 3‐hydroxypropionate cycle) and degradation (e.g., pectin and hemicellulose hydrolysis) by 55.81% and 65.48%, respectively. Partial least squares path modeling identified mucus nutrients and microbial community composition as key contributors to carbon metabolic potential. This research confirms that mucus acts as a trigger, reshaping microbial profiles around corals and enhancing carbon utilization efficiency, highlighting its essential role in carbon metabolism and the maintenance of high productivity in coral reef ecosystems.

Adverse effect of TWPs on soil fungi and the contribution of benzothiazole rubber additives

Tire wear particles (TWPs) pollution is widely present in soil, especially in areas severely affected by traffic. Herein, regular variation of fungal biomass with TWPs was found in soils with different distances from the highway. In addition, the concentrations of benzothiazole compounds (BTHs), an important class of rubber vulcanization accelerators, were found to be positively correlated to the TWPs abundance. Sixty days' soil microcosm experiments were conducted to further confirm the adverse effect of TWPs and BTHs on soil fungi. TWPs spiking at 1000 mg/kg, a detectable level in the roadside, resulted in significant reduction of biomass and significant changes of soil fungal community structure, with Eurotium and Polyporales being the sensitive species. BTH+ 2-hydroxybenzothiazole (OHBT) (the dominant BTHs in soil) spiking at 200 ng/kg, the dose equivalent to 1000 mg/kg TWPs pollution, also caused a similar magnitude of soil fungal biomass reduction. Adonis demonstrated no significant difference of fungal community structure between TWPs and BTH+OHBT spiked soil, suggesting the adverse effect of TWPs on soil fungi may be explained by the act of BTHs. Pure culture using the representative soil fungi Eurotium and Polyporales also confirmed that BTHs were the main contributors to the adverse effect of TWPs on soil fungi.

Difference in microbial community structure along a gradient of crater altitude: insights from the Nushan volcano.

The variation in the soil microbial community along the altitude gradient has been widely documented. However, the structure and function of the microbial communities distributed along the altitude gradient in the crater still need to be determined. We gathered soil specimens from different elevations within the Nushan volcano crater to bridge this knowledge gap. We investigated the microbial communities of bacteria and fungi in the soil. It is noteworthy that the microbial alpha diversity peaks in the middle of the crater. However, network analysis shows that bacterial (nodes 760 vs 613 vs 601) and fungal (nodes 328 vs 224 vs 400) communities are most stable at the bottom and top of the crater, respectively. Furthermore, the soil microbial network exhibited a decline, followed by an increase across varying altitudes. The core microorganisms displayed the highest correlation with pH and alkaline phosphatase (AP, as determined through redundancy analysis (RDA) and Mantel tests for correlation analysis. The fungal community has a higher number of core microorganisms, while the bacterial core microorganisms demonstrate greater susceptibility to environmental factors. In conclusion, we utilized Illumina sequencing techniques to assess the disparities in the structure and function of bacteria and fungi in the soil.IMPORTANCEThese findings serve as a foundation for future investigations on microbial communities present in volcanic soil.

Microbial community structure and function in a sandy soil column under dynamic hydrologic regimes

The capillary fringe (CF) exhibits steep chemical and redox gradients, representing a critical reactive interface in the subsurface. The spatial extent of the CF is temporally dynamic because of water table and soil moisture fluctuations. To simulate the spatio-temporal responses of the CF’s microbial community structure and activity, a 91 cm long sandy soil column experiment was conducted by imposing three different sequential hydrologic regimes: a stable water table separating the unsaturated and saturated zones (static regime), periodic pulse infiltration events with a constant water table position (infiltration regime), and water table fluctuations under three drainage-imbibition cycles of 6, 12, and 18 days (fluctuating regime). The investigation focused on the microbially-mediated turnover of nitrogen (N) and carbon (C). Geochemical profiles in the soil column were monitored continuously, while microbial DNA was extracted for 16S rDNA sequencing at the start, middle and end of the experiment. The observed microbial community compositions corresponded to five categories: (1) initial soil, (2) near-surface and (3) CF and saturated soil under the infiltration regime, (4) unsaturated and (5) saturated soil in the fluctuating regime. Based on co-occurrence network analysis, microbial physiologies matched the predominant geochemical conditions, and relatively stable community structures prevailed throughout the experiment. NO3- and NH4+ were more available to the microbes in the fluctuating regime’s alternating oxic/anoxic zone, leading to a more flexible network. The prevalent microbial metabolic pathways predicted using FAPROTAX were mainly associated with N and C metabolisms and significantly correlated with the taxonomic compositions. However, the dominant microbial groups were shared among all the soil samples. The limited spatial differences in microbial community structure under the fluctuating regime were likely due to a more pronounced role of microbial activity than microbial diversity, and similar drying-wetting conditions between the soil column and the filed site. Internally consistent geochemical and microbial depth stratifications were identified by (1) the redox potential and nitrogen species distributions, (2) spatial moment analysis of NO3- and NH4+ concentrations, (3) microbial community composition and (4) function. The five imposed hydrologic regimes generated distinct and coupled geochemical and microbial signatures. These signatures resulted from variations in the soil microbial community’s activity, rather than diversity or abundance.

Ecological assessment of macrobenthic communities in Chabahar Bay, the Gulf of Oman

AimAssessing the potential of the Chabahar Bay coasts for classification as marine and coastal protected areas. LocationChabahar Bay, northeast of the Gulf of Oman. PeriodTwo seasons from 2017 to 2019. Major taxa studiedMacrobenthic invertebrates. MethodsThe evaluation was based on the 2008 International Union for Conservation of Nature (IUCN) ecological model categories and criteria/sub-criteria. The study investigated criteria such as biodiversity, naturalness, dependency, representativeness, uniqueness, productivity, vulnerability, and integrity; the study was conducted at four zones of three stations within three regions. ResultsThe northern region of Chabahar Bay showed significant differences in community structure compared to the other two regions. The highest abundance of macrobenthic invertebrates was observed in the northern area of Chabahar Bay, whereas the lowest abundance was observed in Konarak. Macrobenthic abundance, salinity, and electrical conductivity (EC) were found to influence the community structure of macrobenthic organisms; each region was assigned a score, categorizing it as an IUCN Category II protected area. Main conclusionsThe AMBI analysis revealed that some ecosystems in the studied regions were alarmingly disturbed, indicating the need for management attention to protect and conserve these ecosystems.

Comparison of the coexistence pattern of mangrove macrobenthos between natural and artificial reforestation.

The abandoned pond-to-mangrove restoration project provides greater advantages than tidal flats afforestation in restoring mangrove ecosystem services and will be the primary method for mangrove restoration in the future. The existing methods for abandoned pond-to-mangrove restoration include artificial restoration through 'dike-breaking, filling with imported soil and tree planting' and natural restoration through 'dike-breaking and natural succession'. However, little is known about which restoration strategy (natural or artificial restoration) provides more benefits to the biodiversity of mangrove macrobethos. Given a prevailing view suggested that artificial restoration should be the preferred approach for accelerating recovery of biodiversity and vegetation structure in tropical regions, we hypothesised higher macrobenthic biodiversity and more complex community structure in artificial restoration than in natural restoration. To test this hypothesis, macrobenthic biodiversity and ecological processes were monitored in a typical abandoned pond-to-mangrove area of Dongzhaigang Bay, China, where artificial and natural restoration methods were used concurrently. Differences in macrobenthic biodiversity, community structure and ecological processes were compared using diversity indices, complex network analysis and null models. Similar species composition and ecological niche overlap and width among macrobenthos were observed at artificial and natural restoration sites. The biotic heterogeneity and interaction among macrobenthos were higher at the natural restoration sites than at the artificial restoration sites. Macrobenthos community assembly at natural and artificial restoration sites was both determined by deterministic processes, with environmental filtering dominating, which explained 52% and 54% of the variations in macrobenthic community structures respectively. Although our findings did not validate the research hypothesis, higher biotic heterogeneity and species interaction among macrobenthos could support natural restoration as the primary method for abandoned pond-to-mangrove projects, because it is a nature-based solution for mangrove restoration.

Disentangling plant- and environment-mediated drivers of active rhizosphere bacterial community dynamics during short-term drought

Mitigating the effects of climate stress on crops is important for global food security. The microbiome associated with plant roots, the rhizobiome, can harbor beneficial microbes that alleviate stress, but the factors influencing their recruitment are unclear. We conducted a greenhouse experiment using field soil with a legacy of growing switchgrass and common bean to investigate the impact of short-term drought severity on the recruitment of active bacterial rhizobiome members. We applied 16S rRNA and 16S rRNA gene sequencing for both crops and metabolite profiling for switchgrass. We included planted and unplanted conditions to distinguish environment- versus plant-mediated rhizobiome drivers. Differences in community structure were observed between crops and between drought and watered and planted and unplanted treatments within crops. Despite crop-specific communities, drought rhizobiome dynamics were similar across the two crops. The presence of a plant more strongly explained the rhizobiome variation in bean (17%) than in switchgrass (3%), with a small effect of plant mediation during drought observed only for the bean rhizobiome. The switchgrass rhizobiome was stable despite changes in rhizosphere metabolite profiles between planted and unplanted treatments. We conclude that rhizobiome responses to short-term drought are crop-specific, with possible decoupling of plant exudation from rhizobiome responses.

Bioregionalization of the subarctic Pacific based on phytoplankton phenology and composition

The subarctic Pacific is generally perceived as relatively homogeneous since the North Pacific Subpolar Gyre dominates the water circulation in the area. However, previous research showed significant spatial differences in phytoplankton abundance and community structure. This study aimed to identify regions associated with distinct phytoplankton phenology and composition to comprehensively describe the main phytoplankton variability patterns across the subarctic Pacific. To this end, satellite GlobColour time series observations and an extensive in situ phytoplankton pigment dataset were used in the analysis. Five bioregions were identified, based on the Self-Organized Mapping technique, using a greater than 20-year satellite data series. The bioregions in the open Pacific waters were dominated by green algae, haptophytes, and pelagophytes and were divided into the areas affected by the North Pacific Transition Zone and beyond. The other bioregions were defined around the Pacific basin margins where the diatom contribution was generally higher, with a particular distinction of waters surrounding the Kuril and the Aleutian Islands. Our bioregion designations allow for future evaluation of the processes controlling the physical and biological dynamics within each bioregion, which has direct implications for foraging conditions available to higher trophic levels, including potential food resource competition.

Pharmaceutical Pollution Alters the Structure of Freshwater Communities and Hinders Their Recovery from a Fish Predator.

Freshwater ecosystems are under threat from rising pharmaceutical pollution. While such pollutants are known to elicit biological effects on organisms, we have limited knowledge on how these effects might cascade through food-webs, disrupt ecological processes, and shape freshwater communities. In this study, we used a mesocosm experiment to explore how the community impacts of a top-order predator, the eastern mosquitofish (Gambusia holbrooki), are mediated by exposure to environmentally relevant low (measured concentration: ∼10 ng/L) and high concentrations (∼110 ng/L) of the pervasive pharmaceutical pollutant fluoxetine. We found no evidence that exposure to fluoxetine altered the consumptive effects of mosquitofish on zooplankton. However, once mosquitofish were removed from the mesocosms, zooplankton abundance recovered to a greater extent in control mesocosms compared to both low and high fluoxetine-exposed mesocosms. By the end of the experiment, this resulted in fundamental differences in community structure between the control and fluoxetine-treated mesocosms. Specifically, the control mesocosms were characterized by higher zooplankton abundances and lower algal biomass, whereas mesocosms exposed to either low or high concentrations of fluoxetine had lower zooplankton abundances and higher algal biomass. Our results suggest that fluoxetine, even at very low concentrations, can alter aquatic communities and hinder their recovery from disturbances.

Intestinal microbiota was closely related to feed efficiency of Larimichthys crocea fed two fishmeal-free diets

This study examined the link between feed efficiency (FE) and intestinal microbiota in Larimichthys crocea fed on fishmeal-free diets. Two types of fishmeal-free diets were formulated: a plant protein-based feed (Group P) and a mixed-protein feed (Group M). These two types of diets were utilized to rear the two groups of L. crocea for 28 days, each consisting of individuals that were 18 months old. Initial and final weights, as well as feed consumption, of the experimental fish were documented. FE was calculated for each fish based on this data. Post-experiment, samples were taken from fish with high and low FE for 16S rRNA gene sequencing. In the Group M, the high and low FE fishes were designated as MH (proximal intestine, MHp; distal intestine, MHd) and ML (proximal intestine, MLp; distal intestine, MLd). In the Group P, the high and low FE fishes were designated as PH (proximal intestine, PHp; distal intestine, PHd) and PL (proximal intestine, PLp; distal intestine, PLd). The results indicated that in Group M, there was no significant difference in microbial community structure between MH and ML, but the microbial diversity and species richness in MH were higher than that in the corresponding ML. MHp showed a significantly higher abundance of the orders Elsterales, Frankiales, and the family Hyphomicrobiaceae compared to MLp. MHd, in comparison to the MLd, had a significant higher abundance of the order Burkholderiales. There was also no significant difference in microbial community structure between PH and PL, but the microbial diversity in PH was lower than that in the corresponding PL. PHp showed a significantly higher abundance of Proteobacteria and GammaProteobacteria compared to PLp; whereas, the significant difference between PHd and PLd was only present in PLd. Microbial functional prediction analysis showed that the intestinal microbiota was mainly involved in carbohydrate metabolism, energy metabolism and vitamin metabolism pathways. These findings of this study contribute to our further understanding of the relationship between intestinal microbiota and the FE traits of the host. The microbial markers found between the high and low FE groups can offer insights and serve as a reference for subsequent research aiming to improve FE using Nutrition and Genetic Selection Techniques.

Exploring the relationship of Gut Microbiota in Obesity and Athletes

This study investigates the relationship between gut microbiota composition and its implications on obesity and athletic adolescents. We compared the gut microbiota between twenty athletes (Group A) and twenty overweight or obese adolescents (Group B) by high-throughput sequencing of bacterial rRNA genes. The results showed a significant reduction in microbial richness in Group B compared to Group A, along with significant differences in microbial community structures. Notably, athletes displayed a greater microbial diversity, potentially contributing to better metabolic health outcomes. In contrast, the obese group exhibited a dominance of Bacteroides, which correlates with higher body mass index (BMI) and may influence obesity-related health issues.