Community Analysis Research Articles

Enhancing effect of conductive materials and rumen microorganisms on the anaerobic digestion performance of a real traditional Chinese medicine wastewater

This work evaluated the effect of different concentrations of conductive materials and rumen microorganisms on the anaerobic digestion (AD) performance of real traditional Chinese medicine (TCM) wastewater. The experiments first determined the optimal organic concentration of 0.25 L/L for the AD system and removed suspended solids from real TCM wastewater to reduce the inhibition effect on methanogenesis. Analysis of the modified Gompertz model showed that the addition of activated carbon, biochar, cow manure, and rumen fluid at doses of 12 g/L, 12 g/L, 12 mL/L, and 125 mL/L, respectively, had the greatest effect on CH4 production, increasing the cumulative CH4 yield by 13.5 %, 10.4 %, 26.8 %, and 32.9 %. Through microbial community and metabolism pathway analyses, the conductive materials promoted direct interspecies electron transfer (DIET) between Clostridium and Methanothrix, and the acetoclastic methanogenic pathway dominated by acetyl-CoA synthase. Rumen microorganisms enhanced AD performance by promoting the growth of hydrogenotrophic methanogens and the abundance of genes dominated by formylmethanofuran dehydrogenase in the hydrogenotrophic methanogenic pathway, illustrating the relationship between microbial community and metabolism pathway. Rumen microorganisms increased CH4 production more than conductive materials in real TCM wastewater. This study helps to better understand the internal mechanisms by which different materials enhance AD performance.

Influence of Bisphenol A concentration on organic matter removal and nitrification in biological wastewater treatment

Microplastics and plastic additives have become ubiquitous in our environment, posing a major challenge to wastewater treatment processes. This study investigated the impact of Bisphenol A (BPA), a common plastic additive, on the efficiency of organic matter removal and nitrification in biological wastewater treatment. The obtained results indicated that a BPA concentration of 10mg·L-1 in the influent affected the Chemical Oxygen Demand (COD) in the effluent. In comparison, concentrations of 1 or 5mg·L-1 did not show such noticeable differences. Additionally, an increase in BPA load inhibited the nitrification process, resulting in a high concentration of nitrogen in its ammoniacal form in the effluent when the BPA concentration was increased to 10mg·L-1. In fact, the microbial community analysis revealed a considerable reduction of Nitrosomonas in the reactor fed with wastewater containing 10mg·L-1 of BPA. Despite compromising the nitrification process, this situation did not deprive the biomass of its ability to remove BPA from the system, as this component was not detected in the effluent once the microorganisms completed their adaptation process. 16 S rRNA gene sequencing showed that the predominant phyla across all samples were associated with Proteobacteria, Bacteroidota, Patescibacteria and Actinobacteriota, similar to previous studies.

Tree species selection for optimizing soil carbon storage: Insights from litter decomposition and bacterial community analysis in coastal ecosystems

Coastal wetland ecosystems are critical sinks for atmospheric carbon dioxide, playing a vital role in global carbon cycling and climate regulation. The decomposition of leaf litter plays a crucial role in the formation and stability of soil organic carbon (SOC) in these environments. This study investigated the impact of leaf litter decomposition from five tree species (Populus deltoids, Ligustrum lucidum, Taxodium 'Zhongshanshan', Hibiscus hamabo, and Nerium oleander) on SOC dynamics, humus composition, and soil bacterial community structure in a tidal flat. Litterbags were used to monitor the mass loss and changes in litter chemical composition over 270 days. The results revealed significant differences in decomposition rates among the tree species, with Nerium oleander exhibiting the fastest decomposition and Populus deltoids the slowest. Surprisingly, initial litter chemistry did not correlate with decomposition rates; however, changes in lignin and hemicellulose content during decomposition were significantly related to mass loss. Despite its rapid decomposition, Nerium oleander litter resulted in the highest accumulation of SOC, total humus, and humin compared to the other species, challenging the conventional view that slower decomposition leads to greater SOC storage. The soil microbial community structure was significantly influenced by SOC, humus, and litter components, with distinct microbial assemblages associated with each tree species. A random forest model identified key bacterial taxa, predominantly Proteobacteria, as important predictors of SOC content, highlighting the role of bacterial diversity in regulating SOC dynamics. These findings underscore the importance of considering litter quality, decomposition dynamics, and bacterial community composition in strategies aimed at enhancing soil carbon sequestration. This study suggests that selecting tree species with rapidly decomposing litter, such as Nerium oleander, in coastal plantations can be an effective management tool for optimizing soil carbon storage, offering valuable insights for mitigating climate change impacts.

Nano-Fe3O4/FeCO3 modified red soil-based biofilter for simultaneous removal of nitrate, phosphate and heavy metals: Optimization, microbial community and possible mechanism

The pollution of nitrogen, phosphorus and heavy metals in surface water is becoming more and more serious, affecting the safety of water quality. In this study, three biofilters were constructed using iron-modified red soil-based filler carriers (RSC, nano-Fe3O4@RSC, and FeCO3@RSC) combined with strain Zoogloea sp. ZP7 to simultaneously remove nitrate (NO3--N), phosphate (PO43--P), copper (Cu2+), and zinc (Zn2+). The long-term operation results showed that the three groups of biofilters could remove 85.0, 90.0, and 89.8% of NO3--N, respectively. Furthermore, the addition of iron compounds enhanced the removal of PO43--P and the resistance to the stress of Cu2+ and Zn2+ in the biofilter. The analysis illustrated that iron modification improved the redox activity and zeta potential of RSC surface. The secondary structure analysis of the protein showed that the microbial secreted proteins were more compact on the surface of the iron-modified RSC, which facilitated the formation of biofilm on the carrier surface. In addition, the iron-modified RSC-based biofilter also showed excellent NO3--N and PO43--P removal efficiency in the treatment of actual surface water. The microbial community analysis results showed that Zoogloea became the dominant species in the biofilter. On the other hand, the presence of iron-reducing bacteria and the expression iron cycle-related genes may contribute to denitrification under low nutrient conditions.

Diversity Patterns of Bacteria in the Root Zone of Davidia involucrata Along an Altitudinal Gradient

Davidia involucrata has an ancient origin, representing a remnant from the paleotropical flora that thrived during the Tertiary period. Altitudinal gradient acts as a natural testing ground for studying climate change, and research on the distribution patterns of microorganisms along altitudinal gradients is crucial in understanding the adaptability of D. involucrata to climate change. In our study, we examined sample sites ranging from 1600 to 2200 m in elevation, which are part of the primary habitat zone for Davidia involucrata within the Xuebaoding National Nature Reserve. In 2021, field surveys were conducted across four altitudinal gradients (1600 m, 1800 m, 2000 m and 2200 m) of the D. involucrata distribution in the nature reserve. The sampling plots were set in each altitudinal gradient, and three representative and healthy mature trees were selected as sample trees for each plot. Rhizosphere soils were used to test the soil stoichiometry characteristics and root zone microbial communities. Our findings indicated pronounced differences in soil total carbon (TC) and total phosphorus (TP) content and C:P and N:P ratios between the four altitude sites (p < 0.05). Analysis of the bacterial communities revealed higher richness (PD and Chao1 indexes) at ASL2000 and ASL2200 (high altitude) compared to ASL1600 and ASL2000 (low altitude) (p < 0.05). Non-metric multidimensional scaling analysis demonstrated a distinct clustering of bacterial communities between the high and low altitudes (p < 0.01). At the phylum level, Proteobacteria and Acidobacteria were predominant at high altitudes, while Actinobacteria and Chloroflexi dominated at low altitudes. The core microbiome, shared among all altitudes, comprised 377 genes. The analysis of differential abundance revealed notable disparities in the prevalence of certain bacterial genera with altitude, with Arthrobacter and Acidothermus experiencing the most pronounced shifts (p < 0.05). This confirmed that environmental factors significantly influenced bacterial community structure and abundance. Spearman’s rank correlations revealed that both Chao1 and PD indices were positively correlated with elevation, TC, and TN, with Chao1 showing stronger relationships. Both indices were negatively correlated with MAT, while only Chao1 exhibited a significant negative correlation with pH. Linear regression analysis further confirmed the significant associations between Chao1 index and elevation, TN, MAT, and pH. Furthermore, redundancy analysis demonstrated that altitude (ASL) and TN were the primary factors shaping soil bacterial community composition, explaining 21.32% and 30.70% of the variance, respectively. Altitude significantly influenced microbial community structure (p = 0.003). Distinct microbial taxa showed specific associations with environmental gradients, suggesting niche specialization in response to soil conditions. These findings suggest that altitude influences soil nutrient characteristics and microbial community composition in the D. involucrata habitat, offering insights into the ecological factors affecting this endangered species.

“Air Laut Macam Daun Pandan” (The Sea is Like Pandan Leaf): Pulau Pinang Fishing Communities, Contested Development and “Anti-Politics”

This study identifies the developmental pathway that is taking place in the state of Pulau Pinang. The focus is on the responses of the ordinary people, namely fishing communities to the development pace of Pulau Pinang (island), the contestation on “developmental” discourses with the state (namely Pulau Pinang State Government, PSG), and the ways in which state institutions and communities construct the narrative of “development”. Through participant observation in the field sites with the fishing community and secondary resources analysis, the article showcases the contested meaning of “development”. The research findings are on the one hand by the PSG, which is underpinned by neoliberal economic principles, on the other hand, by the communities at large, which is multifaceted in nature.

Comparative analyses on nitrogen removal microbes and functional genes within anaerobic-anoxic-oxic and deoxidation ditch sewage-treating processes in Wuhan and Xi'an cities, China.

Anaerobic-anoxic-oxic (A2/O) and deoxidation ditch (DOD) processes are being increasingly preferred owing to their effectiveness in treating various wastes in wastewater treatment plants (WWTPs). Considering seasonal variations is crucial in optimizing treatment processes, ensuring compliance with regulations, and maintaining the overall efficiency and effectiveness of WWTPs. This study aimed to determine the influence of seasonality on nitrogen removing microbes and functional genes within A2/O and DOD processes in the humid Wuhan and semi-arid Xi'an cities, China. The physicochemical parameters of water quality were determined, and molecular and bioinformatic analyses of the bacterial community and nitrogen metabolism functional genes in the two different treatment processes of two WWTPs were performed over four seasons. Our analyses revealed a significant difference in all physicochemical parameters across all experimental groups (p < 0.05). At the genus level, the abundance of Dokdonella, one unidentified genus of Nitrospiraceae, Terrimonas, and one unidentified genus of Chloroflexi was the highest in all groups. Generally, warmer seasons exhibited higher biodiversity indices. The A2/O system exhibited higher values in terms of most nitrogen metabolism functional genes than those of the DOD sewage treatment system. In both WWTPs, the abundance of most genes in spring and summer were higher than that of autumn and winter seasons. Taken together, changes in temperature, caused by seasonal changes, may contribute to changes in abundance of nitrogen metabolic functional genes.

Current status of zoobenthic fauna associated with macroalgae fields from the southern Romanian Black Sea coast

The European environmental policies related to marine water management require a periodic environmental status assessment. The Marine Strategy Framework Directive 2008/56/EC clearly specifies that assessment must take into consideration benthic habitat types, including their associated biological communities. The aim of this study is to present the results of the ecological analysis of the zoobenthic communities associated with benthic habitats with macrophytic substrate and to provide new data regarding the qualitative and quantitative structure of macroinvertebrates that populate these habitats type. The broad habitats type Infralittoral rock and biogenic reef and Infralittoral sands were investigated. The analyzed data covers the summer season, 2023 based on the processing of 13 samples collected from Navodari to 2 Mai – Vama Veche, on depths ranging between 1m to 3 m. A total of 80 macrozoobenthic species were found in all macrophytic assemblages, the Polychaeta, Crustacean and Gastropod were the dominant groups, especially Perinereis cultrifera, Platynereis dumerilii, Ampithoe ramondi, Stenothoe monoculoides, Rissoa splendida, Tricolia pullus registering a large number of individuals. For data interpretation a synecological analysis was performed allowing the identification of the species with the most significant contribution in the ecosystem in terms of function, energy exchanges with the environment, the characteristic species of a biotope or those that have an accidental presence in the studied area.

Enrichment of acid-tolerant sulfide-producing microbes from an acidic pit lake.

High concentrations of harmful metal(loid)s and extreme acidity are persistent environmental concerns in acidic pit lakes. In this study, we examine Cueva de la Mora (CM), a meromictic pit lake in the Iberian Pyrite Belt, Spain, as a model system. Our research aims to explore potential bioremediation strategies to mitigate the impacts of metal(loid)s and acidity in such environments. The major strategy applied in this research is to biologically stimulate sulfate reduction (i.e., biosulfidogenesis) in the deep layer of the lake to promote the formation of low-solubility sulfide minerals. Previous omics-based studies of CM have shown that several sulfate-reducing bacteria (SRB) taxa are present in the deep layer. However, their activities are likely limited by the availability of electron donors for sulfide production. Therefore, different amendments (glycerol, elemental sulfur, and glycerol + elemental sulfur) were tested to promote sulfide production and enrich acid-tolerant sulfide-producing microbes. Our results showed that glycerol stimulated dissimilatory sulfate reduction much faster than elemental sulfur alone, suggesting that electron donor limitations control sulfide production. Furthermore, the combined addition of glycerol and elemental sulfur (S(0)) resulted in the highest level of sulfide production. This indicates that S(0) can play a significant role as an electron acceptor in further promoting sulfide production when a suitable electron donor is present. Microbial community analysis revealed that Desulfosporosinus acididurans, a previously discovered acid-tolerant SRB, was enriched and became the dominant species in incubations with glycerol only (~76-96% abundance) or the combination of glycerol and S(0) (~93-99% abundance).

Enhancement of the anaerobic biodegradation efficiency of azo dye by anthraquinone-loaded biochar biofilm: factors affecting biofilm formation and the enhancement mechanism

Carbon-based materials that serve as microbial carriers, and the role of surface-formed biofilms in anaerobic digestion, merit further investigation. This study explored the role and mechanism behind the biodegradation enhancement of biofilms formed onto anthraquinone-loaded biochar (AQS-BC) surfaces through the anaerobic decolorization process of azo dye Reactive Red 2, and optimized the conditions for AQS-BC biofilm formation. The results indicated that the AQS-BC biofilm system exhibited high treatment efficiency and stability in RR2 anaerobic decolorization. RR2 led to the accumulation of volatile fatty acids (VFAs) and inhibition of methane production, while the presence of AQS increased methane production. The effects of sludge concentration, contact time, carbon source concentration, and RR2 concentration on biofilm maturity were also analyzed. Combining biochemical characteristics, electrochemical properties, surface structure, and microbial community analysis, a mechanism for the anaerobic decolorization of RR2 via AQS-BC as a microbial carrier was proposed. This study provides insights into the roles of biofilms in the anaerobic wastewater treatment processes.Graphical

HulaCCR1, a pump-like cation channelrhodopsin discovered in a lake microbiome

Channelrhodopsins are light-gated ion channels consisting of seven transmembrane helices and a retinal chromophore, which are used as popular optogenetic tools for modulating neuronal activity. Cation channelrhodopsins (CCRs), first recognized as the photoreceptors in the chlorophyte Chlamydomonas reinhardtii, have since been identified in diverse species of green algae, as well in other unicellular eukaryotes. The CCRs from non-chlorophyte species are commonly referred to as bacteriorhodopsin-like cation channelrhodopsins, or BCCRs, as most of them feature the three characteristic amino acid residues of the “DTD motif” in the third transmembrane helix (TM3 or helix C) matching the canonical DTD motif of the well-studied archaeal light-driven proton pump bacteriorhodopsin. Here, we report characterization of HulaCCR1, a novel BCCR identified through metatranscriptomic analysis of a unicellular eukaryotic community in Lake Hula, Israel. Interestingly, HulaCCR1 has an ETD motif in which the first residue of the canonical motif is substituted for glutamate. Electrophysiological measurements of the wild-type and a mutant with a DTD motif of HulaCCR1 suggest the critical role of the first glutamate in spectral tuning and channel gating. Additionally, HulaCCR1 exhibits long extensions at the N- and C-termini. Photocurrents recorded from a truncated variant without the signal peptide predicted at the N-terminus were diminished, and membrane localization of the truncated variant significantly decreased, indicating that the signal peptide is important for membrane trafficking of HulaCCR1. These characteristics of HulaCCR1 would be related to a new biological significance in the original unidentified species, distinct from those known for other BCCRs.

Enhancement of hydrogen production in dark fermentation of corn stover hydrolysates through composite electric field pretreatment: Improving enzymatic efficiency and regulating microbial metabolic balance

This study investigates the effects of composite electric field pretreatment (CEP) on hydrogen production from corn stover enzymatic hydrolysates in dark fermentation. The findings reveal that under optimal conditions, the CEP group achieved a cumulative hydrogen yield of 77.3 ± 2.6 mL/g TS, marking a 55.3 % increase compared to the control group without the electric field. CEP significantly enhances the fermentation capacity of enzymatic hydrolysates during the acid-stage of dark fermentation by disrupting the lignin structure and optimizing cellulase hydrolysis efficiency. Additionally, pH self-regulation is facilitated through the interaction between volatile fatty acids (VFAs) and ammonia nitrogen. Microbial community analysis revealed that CEP shifts the metabolic balance between Clostridium_sensu_stricto_1 and Lactococcus, leading to increased hydrogen yield and concentration during acid fermentation. Notably, Terrisporobacter exhibited a superior acid-producing capability compared to Bacteroides during the dark fermentation of enzymatic hydrolysates. This study provides a new perspective for the practical application of corn stover.

Methodology comparison of environmental sediment fungal community analysis

Fungi play important roles in ecosystems. Analyzing fungal communities in environments has long been a challenge due to the large difference in compositions retrieved using different methods or sequencing regions, obscuring the true abundance and species information. Our study aimed to compare and determine more accurate approach for evaluating fungal populations in river sediment. To achieve this, different primer sets in the internal transcribed spacer (ITS) (ITS5/ITS1R, ITS1F/ITS2), 18S rRNA gene (0817F/1196R) for High-throughput sequencing (HTS), metagenomic shotgun sequencing (MS) directly from environmental samples, and HTS using ITS primers for the fungal samples collected from plate cultivation were used to characterize the fungal communities. We calculated diversity index and used FungalTraits to analyze methods preferences for fungal species. The study revealed that when analyzing the fungal species directly from environmental samples, amplification and sequencing of ITS region demonstrated more accuracy than MS and 18S rRNA gene sequencing methods, but displayed significant primer preference. Over 30 % fungal species from HTS after plate cultivation were not present in HTS from the environmental samples. NMDS analysis demonstrated significant disparities in species diversity among different methods, suggesting potential complementarity between them. Over 85% species identified by HTS using ITS primers belonged to filamentous fungi, while the MS mostly identified yeast (62%). Therefore, to get more accurate fungal community information in sediment, multiple methods were recommended by using cultivation, molecular biological methods dependent on PCR techniques like ITS1F/ITS2 primer for HTS and PCR independent method such as metagenomic shotgun sequencing techniques.

Occurrence of Centrosaurus apertus (Ceratopsidae: Centrosaurinae) in Saskatchewan, Canada, and expanded dinosaur diversity in the easternmost exposure of the Late Cretaceous (Campanian) Dinosaur Park Formation

Late Campanian terrestrial communities of western Canada are best known from the fluvial–paralic deposits of the Dinosaur Park Formation (DPF) in Dinosaur Provincial Park (DPP), Alberta. However, a growing list of localities from isolated DPF outcrops, outside of the DPP area, offers a glimpse into palaeocommunities that evolved isochronously with DPP biotas in greater proximity to the Western Interior Seaway. Over the past decade, one such locality was explored along Lake Diefenbaker in Saskatchewan Landing Provincial Park. The initial palaeoecological analysis of this marginal marine community was based on palynomorph and vertebrate microfossil diversity and has laid a foundation for the current study of its monodominant ceratopsian bonebed. The latter has resulted in new occurrences of Centrosaurus apertus and of the elmisaurine Citipes elegans for Saskatchewan based on incomplete yet diagnostic specimens. Centrosaurus apertus is unequivocally identified by a parietal bar bearing two prominent P1 and P2 hooks, which expands the geographical and habitat range of this species to the most coastal environment known from the DPF. Furthermore, the presence of Centrosaurus apertus suggests that the DPF in this region of Saskatchewan is closer in age to the lower DPF than to the uppermost DPF in DPP, which is at odds with a previous palynostratigraphic interpretation. The faunal composition of this bonebed also supports the presence of a widely distributed metacommunity across these deposits. This contribution demonstrates how evidence from multiple localities in the DPF along a spatial gradient, beyond the temporal gradient available within DPP alone, expands the picture of this metacommunity as a potential model system for biotic turnover in response to sea level rise at a geological temporal scale.

Microbial Community Analysis Offers Insight into the Complex Origins of Plant Disease in a Smallholder Farm Context

Classical approaches to plant disease diagnosis assume a single pathogen/single disease paradigm. Here, we revisit the presumed role of Fusarium oxysporum as the causal agent of wilting and yellowing of chickpea plants on smallholder farms in Ethiopia. Contrary to expectations, detection of Fusarium DNA using conserved PCR primers failed to associate the pathogen with symptomatic plants. Instead, culture-independent sequencing of microbial communities nominated unexpected pathogens and revealed patchiness in the assembly of common microbial consortia. Surprisingly, tests of differential enrichment identified Phytophthora as the most common disease-associated taxon. More generally, across all field sites, multilevel pattern analysis identified indicator taxa whose patterns of co-occurrence demarcate discrete microbial communities and are consistent with a range of specific interactions, including mutualism and antagonism. Taken together, these data indicate that soilborne chickpea disease in Ethiopia has heterogeneous origins and that despite decades of emphasis and disease resistance breeding, the role of Fusarium as the frequent agent of chickpea disease in Ethiopia remains enigmatic.

Influence of host-specific and locally isolated multi-strain probiotics on piglet performance, mortality, inflammatory response, and gut microbiome.

This study aimed to assess the impact of host-specific and locally isolated multi-strain probiotics on piglet performance, mortality, inflammatory responses, and gut microbiome. A total of 52 piglet litters-34 from Landrace sows and 18 from Large White sows-were allocated to two groups: a control group and a multi-strain probiotic group. The probiotic group comprised seven strains of lactic acid bacteria (MLAB): Lactobacillus brevis, Lactobacillus reuteri, Lactobacillus paraplantarum, Lactococcus lactis, Lactobacillus pentosus, Weissella cibaria, and Pediococcus pentosaceus. Each strain was included in equal concentrations, resulting in a final liquid mixture containing 109 CFU/mL. The MLAB group received the probiotics orally starting from 7 days of age until weaning at four weeks. Following weaning, supplementation continued via feed spraying for an additional four weeks. MLAB supplementation did not significantly affect piglet performance but showed a trend towards reducing the mortality rate (p = 0.06). It influenced the inflammatory response by upregulating the expression of anti-inflammatory cytokines interleukin (IL)-4 and IL-10 (p<0.05). Microbial community analysis indicated that MLAB supplementation increased both microbial diversity (Simpson index: p = 0.06) and species richness (Chao1 index: p = 0.02). Piglets receiving MLAB had a significantly higher abundance of the phylum Firmicutes (p<0.01) compared to the control group, while the abundance of the phylum Bacteroidota was markedly reduced (p<0.01). In addition, the relative abundance of the bacterial genera Prevotellaceae_NK3B31 (p<0.01) and Chlamydia (p = 0.03) was lower in the MLAB group. Overall, these results suggest that while MLAB supplementation does not directly improve piglet growth performance, it has the potential to improve immune function and promote a healthier gut microbiota in weaning piglets, which could ultimately reduce mortality rates.

Impacts of the coexistence of polystyrene microplastics and pesticide imidacloprid on soil nitrogen transformations and microbial communities

The pollution of agricultural soils by microplastics (MPs) and pesticides has attracted significant attention. However, the combined impact of MPs and pesticides on soil nitrogen transformation and microbial communities remains unclear. In this study, we conducted a 28-day soil incubation experiment, introducing polystyrene microplastics (PS-MPs) at concentrations of 0.1% and 10% (w/w) and pesticide imidacloprid at concentrations of 0.1 mg/kg and 1.0 mg/kg. Our aim was to investigate the individual and combined effects of these pollutants on nitrogen transformations and microbial communities in agricultural soils. Imidacloprid accelerated the decline in soil pH, while PS-MPs slowed the process. Imidacloprid hindered soil nitrification and denitrification processes, however, the presence of PS-MPs mitigated the inhibitory effects of imidacloprid. Based on microbial community and functional annotation analyses, this is mainly attributed to the different effects of PS-MPs and imidacloprid on soil microbial communities and the expression of key nitrogen transformation-related genes. Variance partitioning analysis and partial least squares path modeling analyses revealed that PS-MPs and imidacloprid indirectly influenced the microbial community structure, primarily through changes in soil pH. This study elucidates the mechanism through which the combined stress of MPs and pesticides in agricultural soils influence soil nitrogen transformation and microbial communities. The findings offer valuable insights for the systematic evaluation of the ecological risks posed by the coexistence of these pollutants.

Metagenomic analysis of deep-sea bacterial communities in the Makassar and Lombok Straits

The extreme conditions of the deep-sea environment, including limited light, low oxygen levels, high pressure, and nutrient scarcity, create a natural habitat for deep-sea bacteria. These remarkable microorganisms have developed unique strategies to survive and adapt to their surroundings. However, research on the diversity of deep-sea bacteria, both culture-dependent and culture-independent, in Indonesian waters remains insufficient. This study focused on exploring the biodiversity of deep-sea bacteria, specifically in the Makassar and Lombok Strait, the main Indonesian throughflow pathway characterized by relatively fertile water, which serves as an important deep-sea region. High-throughput DNA sequencing of full-length 16S rRNA was employed to construct a genomic database. The results of the bioinformatic analysis revealed that two stations, 48 and 50 (Makassar Strait), exhibited a more similar community structure of deep-sea bacteria than did station 33 (Lombok Strait). Among the predominant phyla found at a depth of 1000 m, the top ten were Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Planctomycetes, Acidobacteria, Nitrospinae, Verrucomicrobia, Candidatus Melainabacteria, and Cyanobacteria. Furthermore, the genera Colwellia, Moritella, Candidatus Pelagibacter, Alteromonas, and Psychrobacter consistently appeared at all three stations, albeit with varying relative abundance values. These bacterial genera share common characteristics, such as psychrophilic, halophilic, and piezophilic tendencies, and are commonly found in deep-sea ecosystem. The environmental conditions at a depth of 1000 m were relatively stable, with an average pressure 10 MPa, temperature 4.68 °C, salinity 34.58 PSU, pH 8.06, chlorophyll-a 0.29 µg/L, nitrate 3.19 µmol/L, phosphate 6.32 µmol/L and dissolved oxygen (DO) 2.90 mg/L. The bacterial community structures at the three sampling stations located at the same depth (1000 m) exhibited similarities, as indicated by the closely aligned similarity index values.

Enhancing biogas production from hemp biomass residue through hydrothermal pretreatment and co-digestion with cow manure: Insights into methane yield, microbial communities, and metabolic pathways

This study investigates the enhancement of biogas production from hemp biomass residue (HBR) through hydrothermal pretreatment and co-digestion with cow manure (CM). Hydrothermal pretreatment at 200 °C for 15 min significantly improved the methane yield from 311.5 to 434.3 mL-CH4/g-VSadded (p ≤ 0.05) from HBR at 10% total solids (TS) loading, a 39% increase. Co-digestion with CM at an optimum ratio of 80:20 further increased the methane yield (738.7 mL-CH4/g-VSadded), representing a 70% improvement over pretreated HBR alone and a 137% increase compared to untreated HBR. Microbial community analysis revealed the dominance of Methanosaeta, comprising 83–93% of archaeal genera across samples. Gene expression analysis showed acetoclastic methanogenesis as the dominant pathway, accounting for 80% of methanogenesis sequences. Hydrogenotrophic methanogenesis and CO2 reduction with H2 pathways contributed 10% each. The optimized process achieved a biodegradation efficiency of 94% for hydrothermally pretreated HBR, compared to 68% for untreated HBR. Mass balance analysis demonstrated that combining hydrothermal pretreatment with anaerobic digestion increased biogas yield from 79% for untreated HBR to 86% for pre-treated HBR (PHBR) co-digested with CM. Integrating hydrothermal pretreatment and co-digestion enhances biogas production from lignocellulosic agricultural residues, contributing to sustainable waste management and renewable energy production.

Biodiversity measures of a grassland plant-pollinator community are resilient to the introduction of honey bees (Apis mellifera).

The prairies of Canada support a diversity of insect pollinators that contribute pollination services to flowering crops and wild plants. Habitat loss and use of managed pollinators has increased conservation concerns for wild pollinators, as mounting evidence suggests that honey bees (Apis mellifera) may reduce their diversity and abundance. Plant-pollinator community analyses often omit non-bee pollinators, which can be valuable contributors to pollination services. Here, we experimentally introduced honey bees to examine how their abundance affects the species richness, diversity, abundance, species composition, interaction richness, and interaction diversity of all wild pollinators, and of four higher taxa separately. We identified all insect pollinators and analyzed how honey bee abundance affected the above biodiversity metrics, controlling for flower abundance and flower species richness. Even with high honey bee densities, there was no change to any of these variables, except that beetle species diversity increased. All other taxa had no significant relationship to honey bee abundance. Considering the widespread use of managed honey bees, the effect they have on wild pollinators should be firmly established. Our results suggest that honey bees have little to no short-term impact on the wild pollinator community or its interactions with plants in this native grassland.