Effects of adaptation to crowded larval environment on the evolution of sperm competitive ability in males of Drosophila melanogaster

Two of the most important environmental factors that affect the sperm competitive ability in males are the availability of resources and the socio-sexual environment. Numerous studies have investigated the individual effects of these factors, but their combined effect on the evolution of sperm competitive ability remains untested. A crowded larval environment is unique because it simultaneously affects the fitness of the organism through both resource availability and the socio-sexual environment. In this study, we used a set of four laboratory populations of D. melanogaster, evolved under a crowded larval environment for more than 165 generations and their respective controls to investigate how the sperm competitive ability of the males is affected by a single generation of larval crowding versus evolution under a crowded larval environment for more than 165 generations. Our results show that larval crowding negatively affects the sperm defence ability of males evolved in a crowded larval environment, while it has no effect on the sperm defence ability of control males. Additionally, larval crowding negatively impacts the sperm offence ability in both control and evolved populations. Males from populations adapted to a crowded larval environment exhibit lower sperm offence ability at an older age compared to control populations.

Circulation characteristics of bat coronaviruses linked to bat ecological factors in Korea, 2021-2022

Considering that bat ecology alterations may be linked with pathogen spillover, research on bat coronaviruses, particularly on the infection and transmission pattern among bats in relation with their ecology, is essential. We captured bats distributed in Korea from 2021 to 2022, examined coronaviruses in oral swabs, feces, urine, and ectoparasites, and were able to detect alphacoronavirus. We investigated coronaviruses, but noted no substantial differences in the body condition index in the coronavirus-positive bats. Binary logistic regression analysis revealed that bat ecological factors that were significantly associated with coronavirus-positive were roost type, sample type, and bat species. Coronavirus-positive ectoparasite cases suggested additional study on the potential role of them as the viral transmission vectors or fomites. Reinfection of a different coronavirus in recaptured bats was evident, suggesting the possibility that coronavirus circulation can evade the potential protective immunity acquired from previous coronavirus infections. The present findings provide comprehensive information on the coronaviruses transmission dynamics within bat populations linked with bat ecology.

Evanescent wave absorbance based label-free detection of microcystin in water and bodyfluids using polyaniline coated optical fiber

An increase in the eutrophication of water bodies globally is leading to a significant increase in harmful cyanobacterial blooms, causing contamination of water with cyanotoxins like microcystins. This poses a serious threat to human health and has far-reaching environmental consequences. Prolonged exposure to microcystin can result in oxidative stress, inflammation, liver damage, and potentially lead to liver cancer. The detection of microcystin typically requires sophisticated tests such as LC-MS, which are expensive, require high maintenance, and trained professionals to conduct. This poses a challenge when regular on-site assessment is necessary. In response, a simple and sensitive fiber optic immunosensor was developed by utilising the optical properties of polyaniline over the fiber surface. This evanescent wave absorbance-based sensor could successfully detect microcystin-LR in matrices such as lake water, urine, and serum with a limit of detection ranging from 0.001 µg/L to 0.004 µg/L. The sensor demonstrated a linear response from 0.1 to 1000 µg/L and excellent selectivity. The recovery results ranged from 88 % to 112 % indicating reasonable accuracy.

Nitrogen addition decouples the microbial necro-mass from soil organic carbon formation in a temperate grassland

Increasing anthropogenic nitrogen (N) inputs has profoundly altered soil microbial necro-mass carbon (MNC), which serves as a key source of soil organic carbon (SOC). Yet, the response pattern of MNC and its contribution to SOC across a wide range of N addition rates, remain elusive. In a temperate grassland with six years' consecutive N addition spanning seven rates (0-50 g N/(m2·year)) in Inner Mongolia, China, we explored the responses of soil MNC and its contribution to SOC. The soil MNC showed a hump-shaped pattern to increasing N addition rates, with the N saturation threshold at 18.07 g N/(m2·year). The soil MNC was driven by nematode abundance and the ratio of bacterial to fungal biomass below the N threshold, and by plant biomass allocation pattern and diversity above the N threshold. The contribution of soil MNC to SOC declined with increasing N addition rates, and was mainly regulated by the ratio of MNC to mineral-associated organic carbon and plant diversity and the ratio of bacterial to fungal biomass. In addition, the soil MNC and SOC differentially responded to N addition and were mediated by disparate biological and geochemical mechanisms, leading to the decoupled MNC production from SOC formation. Together, in this N-enriched temperate grassland, the soil microbial necro-mass production tends to be insufficient as a general explanation linking SOC formation. This study expands the mechanistic comprehension of the connections between external N input and soil carbon sequestration.

Vegetation composition and organic carbon content along right-of-ways on interstate highway 35 in Bexar County, Texas

Roadside habitat through major urban areas may offer remnant examples of natural grasslands. These habitats may be subjected to frequent as mowing and exposure to automobile emissions and runoff. This study was conducted on interstate highway right-of-ways in San Antonio, Texas, U.S.A. We compared the vegetation species and diversity, and the organic carbon of leaf litter, plants, and soils. Two non-native grasses accounted for 50.9 % cover, while all native forbs and grasses accounted for only 9.8 % cover. The mean biomass of non-native grasses was 4.5 times greater than that of all native species. Organic carbon content of leaf litter, plants, and soils was variable among the study sites, possibly due to management practices and a drought that occurred during the study. The mean organic carbon content in the upper 20 cm soil was 5.0 kg C/m2 and organic carbon content was greater in the upper 10 cm than organic carbon in the 10.1 to 20 cm portion. Cynodon dactylon and Bouteloua curtipendula exhibited the greatest photosynthesis efficiency indicating these grasses are more adaptable to hot summer temperatures found in Central Texas. The organic carbon content along a major interstate was 13,793 kg·C/ha for leaf litter, vegetation, and the upper 20 cm of the soil. We conclude that interstate highways provide habitat for some native species, but the vegetation along right-of-ways is dominated by two non-native grasses. It appears unlikely that roadside habitat can be restored to resemble native grasslands without large scale and costly restoration efforts.

Decoupling of diversity and network complexity of bacterial communities during water quality deterioration

Numerous studies have examined the impact of water quality degradation on bacterial community structure, yet insights into its effects on the bacterial ecological networks remain scarce. In this study, we investigated the diversity, composition, assembly patterns, ecological networks, and environmental determinants of bacterial communities across 20 ponds to understand the impact of water quality degradation. Our findings revealed that water quality degradation significantly reduces the α-diversity of bacterial communities in water samples, while sediment samples remain unaffected. Additionally, water quality deterioration increases the complexity of bacterial networks in water samples but reduces it in sediment samples. These shifts in bacterial communities were primarily governed by deterministic processes, with heterogeneous selection being particularly influential. Through redundancy analysis (RDA), multiple regression on matrices (MRM), and Mantel tests, we identified dissolved oxygen (DO), ammonium nitrogen (NH4+-N), and C/N ratio as key factors affecting the composition and network complexity of bacterial communities in both water and sediment. Overall, this study contributes a novel perspective on the effect of water quality deterioration on microbial ecosystems and provides valuable insights for improving ecological evaluations and biomonitoring practices related to water quality management.

Analyzing the contribution of top-down and bottom-up methods to the construction of synthetic microbial communities in Jiuyao

The construction of synthetic microbial communities is a crucial strategy for improving the stability of microbial populations and the quality of fermented foods. Jiuyao, an essential saccharification and fermentation starter in Huangjiu production, was the focus of this study. Using metagenomics combined with culture-dependent methods, we identified 11 microbial species involved in Huangjiu fermentation. Through metagenomic analysis and simulated fermentation, Rhizopus delemar, Rhizopus microspores, Rhizopus stolonife, Rhizopus azygosporus, Saccharomycopsis fibuligera, Saccharomyces cerevisiae, Wickerhamomyces anomalus and Pediococcus pentosaceus were determined to be the core microbial species driving the Jiuyao fermentation process. A synthetic microbial community was constructed based on these species, successfully reproducing the flavor and sensory qualities of Huangjiu while enhancing fermentation efficiency. This study provides valuable insights into the functional roles of Jiuyao-associated microbes and offers a framework for improving microbial community stability and fermentation quality in Huangjiu production.

Charting the invasion: Predicting Tubastraea spp. next move into Brazilian marine protected areas

In the late 1980s, the sun coral, Tubastraea spp. (Scleractinia; Dendrophylliidae), was introduced to Brazil via biofouling on oil platforms and drilling vessels. Today, these corals have spread over 3000 km of the Brazilian coast, colonizing a range of habitats, including oil platforms, drilling ships, monobuoys and natural reefs. Concerned about the potential impacts on Brazilian marine ecosystems, management actions have been implemented in various regions. To achieve success in management, early detection and monitoring are essential. To address this need, our study focuses on modeling the habitat suitability for Tubastraea spp. along the Brazilian coast, aiming to support control and monitoring activities within marine protected areas (MPAs). By utilizing habitat suitability models that incorporate both environmental and anthropogenic predictors, our results indicate a broad potential distribution for Tubastraea spp., with oil and gas extraction identified as the primary influencing factor. Our analysis ranked the most vulnerable Brazilian MPAs to Tubastraea spp. invasion, highlighting the Arapiranga-Tromaí Extractive Reserve, Trindade and Martim Vaz Islands Natural Monument, and the Costa dos Corais Environmental Protected Area as the most threatened. This study offers valuable insights into prioritizing efforts and resources for the control, monitoring, and prevention of sun coral invasion along the Brazilian coast, particularly in light of ongoing discussions about the oil industry's plans to operate at the Amazon River mouth.

Drivers of spatiotemporal community variations in estuarine ecosystems: A case study of the waters adjacent to the Yangtze Estuary

Understanding the processes and mechanisms driving species distribution and spatiotemporal variations in communities is a crucial theme in community ecology and conservation biology. Due to its complex geographical features and natural environmental gradients, the unique conditions of the waters adjacent to the Yangtze Estuary facilitate further research into estuarine community aggregation and diversity patterns. We used Variation Partitioning Analysis (VPA) to link community composition with environmental and spatiotemporal factors, quantifying the contributions of stochastic and deterministic processes to community spatiotemporal variations. Employing Canonical Correspondence Analysis (CCA), multi-variable regression, Mantel tests, and Spearman's rank correlation, we identified the main drivers for different species and communities. The results indicate that the community structure of fish and invertebrates in the waters adjacent to the Yangtze Estuary shows significant spatiotemporal variations. Temporal community changes are mainly driven by environmental factors, with significant biomass declines over years and seasonal β-diversity shifts. Despite the long time series of this study (2004-2022), the degree of seasonal variability in the community remains greater than interannual variability. Spatial variations in the community result from the combined effects of stochastic (random dispersal) and deterministic processes (environmental filtering), with non-demersal communities showing greater spatial changes. Temperature, chemical oxygen demand (COD), and pH are environmental factors with significant driving effects. This study quantitatively analyzed the significant impacts of environmental factors on fish and invertebrate communities by integrating neutral processes, specifically random dispersal, with environmental filtering. It thereby provides crucial information for systematic biodiversity conservation and water environment management planning.

Enhancement of the start-up and performance of an upflow anaerobic sludge blanket (UASB) reactor using electrochemically-enriched biofilm

A novel approach was developed to accelerate the start-up of a 20-L UASB reactor under mesophilic conditions. Two runs were conducted, where the first run (Run I) was inoculated with anaerobic sludge, and the second run (Run II) was inoculated with the same sludge supplemented with enriched electro-active biofilms collected from the working and counter electrodes of anodic and cathodic bio-electrochemical systems (BESs). Reactors' performance and microbial dynamics were monitored over 41 days. Methane production in Run II exceeded 200 mL-CH4/g-COD within 10 days, compared to 29 days in Run I. Run II achieved 80 % removal of soluble COD after 13 days as compared to 23 days in Run I. Sludge washout in Run II stabilized after 3 days, achieving 70 % VSS removal, whereas Run I required 17 days. Greater extracellular polymeric substance (EPS) values and higher protein-to-polysaccharide ratios in Run II may indicate accelerated granules formation mediated by EPS. 16S rRNA gene sequencing analysis results revealed shared genera between both runs but different relative abundances. Methanothrix dominated in Run I, while other archaeal genera, mainly Methanosarcina and Methanobacterium increased in abundance in the Run II. The Enterobacteriaceae family was prevalent in both reactors, with three genera, Citrobacter, Klebsiella, and Enterobacter distinctly dominating at different time points, suggesting potential links with the initial seed sludge or enriched biofilm consortia. The addition of electrochemically grown biofilm in Run II likely enhanced the microbial diversity, contributed to the rapid development of granular syntrophic communities, and improved reactor performance.

Shellfish farming contamination by marine biotoxins: New insights into the ecological toxic dinoflagellate Dinophysis dynamics and DSP (diarrhetic shellfish poisoning) events for safe production management of marine aquaculture

Mussel farming is a strategic economic activity for several coastal regions, where seawater and mussels are regularly monitored for the presence of the toxic dinoflagellate Dinophysis and associated toxins. This study analysed the ecological dynamics of Dinophysis species assemblages in relation to the toxicity events recorded in mussel farms and environmental variables over the multi-year (1998-2023) continuous observations along the Emilia-Romagna and Marche coasts (northwestern Adriatic Sea). DSP (diarrhetic shellfish poisoning) toxicity events were mainly recorded in autumn and winter and were associated with the abundance of D. caudata, D. fortii and D. tripos species (rs = 0.84, rs = 0.83, and rs = 0.66, respectively, p < 0.05). The Dinophysis species showed a clear seasonality with a succession of D. acuminata, D. sacculus in spring-summer, followed by D. caudata and finally D. fortii and D. tripos in autumn. In addition, each Dinophysis species showed its own optimum temperature for maximum growth. Furthermore, interannual trends showed an increase in Dinophysis spp. absence and a decrease in toxicity in bivalve mussels (5.35 and -3.31 % year-1, respectively), accompanied by a decreasing trend in DIN, phosphate and total phosphorus, and chlorophyll a (-1.97 %, -2.64 %, -3.3 % and -1.73 % year-1, respectively). In 2015 and 2022, prolonged toxicity events occurred when the surface waters were colder and slightly saltier than the long-term average. The data analysis highlighted the importance of the long-term observations for understanding the variability of DSP events and Dinophysis dynamics in relation to the environmental conditions to improve the management of aquaculture activities.

Molecular Diet Analysis of Leaf-Grazing Katydids Based on DNA Barcoding

The diversity of herbivorous insects is associated with host plant diversity. The determination of dietary profile is a central topic in insect ecology. DNA barcoding, that is, taxon identification using a standardized DNA region, have been important to the recent advances in food web understandings. In this study, three commonly plant barcoding loci (i.e., rbcL, matK, and trnH-psbA) were chosen for screening of ingested plant DNA in 207 specimens of 18 leaf-grazing katydid species representing 4 subfamilies in China. The obtained sequences were queried against the Barcode of Life Database (BOLD) and GenBank for taxa identification. The results of identification were as follow: 3 Conocephalinae species consumed 10 plant families, with preference for Poaceae; 1 Mecopodinae species consumed 18 plant families, with preference for Fabaceae and Vitaceae; 11 Phaneropterinae species consumed 43 plant families, with preference for Juglandaceae; 3 species Pseudophyllinae species consumed 9 plant families, with preference for Balsaminaceae. Among these, only 81 out of 207 samples were identified at the species level when compares with NCBI and BOLD database. Our study added a significant amount of dietary information for leaf-grazing katydids in China. It is crucial to fully understand coevolution of katydids and plant, katydids diet resource requirements, and best practices for habitat conservation.

Sarcoptic mange in a guanaco (Lama guanicoe) of northwestern Argentina: Clinical, histopathological and molecular studies

Sarcoptic mange, caused by the mite Sarcoptes scabiei, is a highly contagious and potentially fatal skin disease that affects a wide range of mammals, including South American Camelids (SAC). Although the presence of mange has been described in vicuñas and llamas in northwestern Argentina, there are no previous records documenting its presence in guanacos (Lama guanicoe) of this region. We here describe a case of S. scabiei in a free-ranging guanaco in the Department of Tilcara, Jujuy Province. The animal presented alopecic, erythematous and hyperkeratotic lesions with abundant crusts in the ventral region of the body and limbs. Histopathology revealed periadnexal dermatitis with inflammatory infiltrate, severe hyperemia, orthokeratotic and parakeratotic epidermal hyperplasia, and stratum corneum thickening. The etiological agent was identified as S. scabiei by microscopic examination of adult mites. This result was confirmed by sequencing of a cytochrome oxidase subunit I gene fragment, that showed 100 % identity with sequences of isolates from SAC and other mammals. Genotyping of three mites isolated from different parts of the guanaco's body using a set of ten microsatellite markers indicated the infection with a single genetic variant that showed a similar profile to those found in S. scabiei isolates from vicuñas and llamas of the same region. However, genetic differences with guanaco isolates from midwestern Argentina were observed. This work presents the first record of sarcoptic mange in a guanaco in Jujuy Province and in the northwestern region of Argentina, as well as the molecular characterization of the etiological agent. The case highlights an uncertain scenario regarding the health situation of the guanaco population in this region, which is small, fragmented, and locally categorized as endangered. Epidemiological surveillance programs for guanacos and further research on the impact of sarcoptic mange on the conservation of this species are needed.

Epidemiology and risk factors for endoparasite infection in subtropical feral cattle in Hong Kong

Understanding parasite epidemiology is essential for managing endoparasite infections in free-ranging animals. However, such epidemiological knowledge is limited for feral cattle and is usually derived from farmed populations. We assessed endoparasite infection in a feral cattle population in Hong Kong. This population does not receive any routine care or anthelminthic treatment, although some cattle are provisioned with water and hay by local citizens. We assessed three indices of endoparasite infection (parasite richness, prevalence and fecal egg/oocyst count) and their associated risk factors (season, provisioning, marshland access, group size, sex and body condition) in adult cattle. We conducted sedimentation, McMaster and coproculture techniques on 262 samples collected from 177 cattle. We identified eleven taxa of nematodes, two taxa of trematodes, one taxon of protozoan and one taxon of cestode. Median parasite richness was two parasite taxa per individual. Trematode infections were the most prevalent (91.22 %), followed by protozoan (67.17 %), nematode (23.22 %) and cestode (12.97 %) infections. Counts averaged 144.85 oocysts per gram for Eimeria oocysts, 20.61 eggs per gram (EPG) for strongyle-type eggs, 11.83 EPG for Moniezia and 1.91 EPG for Trichuris. Provisioned herds were more likely to be infected with Eimeria, but had lower prevalence of Trichostrongylus. Eimeria prevalence and strongyle-type egg counts were higher in the wet season, while Fasciola eggs, Cooperia and Trichostrongylus larvae were more prevalent in the dry season. Larger herds had higher Eimeria oocyst prevalence but lower Fasciola egg prevalence. Marshland access decreased Fasciola egg prevalence while it increased prevalence of Cooperia larvae. Males were more infected with strongyle-type eggs than female cattle. We show that the seasonal dynamics of infection and consequences of provisioning differ between endoparasite taxa. Our findings highlight complex interactions between endoparasites and their hosts, providing new insights into wild ruminants' health and the impacts of anthropogenic provisioning.

Antarctic krill habitat suitability changes: Historical trends and future projections under climate scenarios

Antarctic krill plays a crucial role in the Southern Ocean ecosystem. However, data limitations leave a significant gap in understanding the changes in krill habitat suitability. This study integrated data from Chinese Antarctic research expeditions and KRILLBASE database, using Maxent model to assess spatiotemporal shifts in krill suitable habitat from 1991 to 2100 across the eastern and western Antarctic under SSP-RCP scenarios. The results reveal regional differences in climate and environmental impacts on krill habitats. Sea temperature and pH are dominant environmental factors affecting habitat suitability. With climate changes, the suitable habitats are shifting toward higher latitudes, and the latitudinal shift of habitats in CCAMLR Areas 48 and 58 is in the opposite direction. Under high-emission scenarios, krill habitats face severe contraction and loss, whereas low-emission scenarios suggest partial recovery by 2100. Coordinated global action to protect krill habitats is essential to address the biodiversity crisis in the Southern Ocean.

Fast-tracking rapid cyanotoxin detection: A novel immunoassay for emerging dihydroanatoxins

Dihydroanatoxin-a and dihydrohomoanatoxin-a are emerging cyanotoxins contaminating freshwater ecosystems, and they have recently been associated with numerous animal fatalities. While immunochemical methods have been developed and commercialized for the rapid analysis of the most relevant cyanotoxins, no highly performant immunoreagents have yet been obtained for these members of the anatoxin family. In the present study, the synthesis of two dihydroanatoxin haptens is described. On the one hand, hapten DAa was prepared with an azide functional group to enable protein conjugation via click chemistry. On the other hand, hapten DAc was synthesized with a carboxyl group to facilitate coupling via the active ester reaction. When the immunogenicity of the corresponding bioconjugates was evaluated, hapten DAc proved to be a more potent immunogen, capable of generating high-affinity antibodies with IC50 values in the low nanomolar range. Furthermore, the resulting binders were able to recognize both dihydroanatoxin-a and dihydrohomoanatoxin-a with similarly high affinity, while showing low binding to anatoxin-a and homoanatoxin-a. These novel immunoreagents were then employed to develop the first reported enzyme-linked immunosorbent assay for the analysis of dihydroanatoxins. The optimized assay achieved a limit of detection for dihydroanatoxin-a as low as 0.04 ng mL-1. No relevant matrix effects were observed when testing four distinct environmental water samples, and the immunoassay demonstrated excellent recovery rates and coefficients of variation across a concentration range of 2 and 4000 ng mL-1 of dihydroanatoxin-a. Thus, this immunoassay offers a powerful strategy for the rapid analysis of dihydroanatoxins and it fills the gap for monitoring the most relevant cyanotoxins.

Ocean acidification and elevated temperatures alter the behavior of a sub-Antarctic fish

The interaction of multiple climate change stressors can affect the behavior of marine fish. While these effects have been reported in tropical and temperate species, much less is known for fish inhabiting high latitudes. We analyzed the combined effects of ocean acidification and the highest and lowest seasonal temperatures on the activity level and boldness of Eleginops maclovinus, an ecologically and commercially important notothenioid fish from the subantarctic area. Juveniles were acclimated for one month to two temperatures (T = 4 and 10 °C) and two pCO2 levels (∼500 and ∼1800 μatm) in a full factorial design. In an open field test, the time spent active was significantly affected by temperature, with fish at 10 °C 1.63 times more active than those at 4 °C, but not by pCO2 or the interaction (T × pCO2). No differences were observed in the average swimming velocity measured when active, nor in the time spent in the inner zone of the tank. A refuge emergence test indicated increased boldness under near-future pCO2 levels with fish emerging 2.06 (4 °C) and 1.23 (10 °C) times faster than those acclimated to present-day pCO2 levels. The disruptions of these fundamental behaviors by these climate-driven stressors could have consequences for foraging and predator-prey interactions, with likely detrimental effects on the interactions among sympatric subantarctic fishes under projected climate change scenarios.

Outbreaks of Ulva prolifera green tides reduce the network complexity and stability of cooccurring planktonic microbial communities

Ulva prolifera green tides are becoming a worldwide environmental problem, especially in the Yellow Sea, China. However, the effects of the occurrence of U. prolifera green tides on the community organization and stability of surrounding microbiomes have still not been determined. Here, the prokaryotic microbial community network stability and assembly characteristics were systematically analyzed and compared between the green tide and non-green tide periods. U. prolifera blooms weaken the community complexity and robustness of surrounding microbiomes, increasing fragmentation and decreasing diversity. Bacteria and archaea exhibited distinct community distributions and assembly patterns under the influence of green tides, and bacterial communities were more sensitive to outbreaks of green tides. The bacterial communities exhibited a greater niche breadth and a lower phylogenetic distance during the occurrence of U. prolifera green tides compared to those during the non-green tide period while archaeal communities remained unchanged, suggesting that the bacterial communities underwent stronger homogeneous selection and more sensitive to green tide blooms than the archaeal communities. Piecewise structural equation model analysis revealed that the different responses of major prokaryotic microbial groups, such as Cyanobacteria, to environmental variables during green tides, were influenced by the variations in pH and nitrate during green tides and correlated with the salinity gradient during the non-green tide period. This study elucidates the response of the adaptability, associations, and stability of surrounding microbiomes to outbreaks of U. prolifera green tides.

Saponins in soil, their degradation and effect on soil enzymatic activities

Saponins can be potential candidates for the development of safe biopesticides, due to their widely acknowledged insecticidal, fungicidal and nematicidal activity, but information on their effects on soil biological properties is still limited. This study aimed to investigate the short-term fate of saponins from Medicago sativa in soil and their dose-effect relationship with microbial biomass and selected enzyme activities in soils with different origin, physical and chemical properties. Microbial degradation of total saponins ranged from 46 % to 91 %, according to soil characteristics, within 28 days from their incorporation into the soil. Both saponin glycosidic chains and triterpenic aglycones were also microbially degraded, though by dynamics changing among the different soils. In all soils, M. sativa saponins significantly reduced microbial biomass at rates of 10 and 20 mg saponin mixture per g of soil. Microbial enzymatic activities were less affected as indicating an adaptive response of soil microbial communities to the presence of saponins.

Assessing the impacts of agricultural practices on ephemeroptera, plecoptera, and trichoptera (EPT) seasonal distribution: A genera-level EPT trait-based study in North Africa's river ecosystems

This study presents a novel trait-based assessment of how agricultural land use and water quality alterations influence EPT (Ephemeroptera, Plecoptera, and Trichoptera) assemblages across different elevations in the Northwestern Rif region of Morocco. Moving beyond taxonomic diversity, we integrate functional traits of EPT to uncover adaptive responses to seasonal variations and anthropogenic stressors. Data were collected from March 2021 to April 2023 across 20 sites categorized by impact intensity, incorporating physico-chemical and hydromorphological parameters alongside EPT traits. We analyzed 11 traits, revealing significant seasonal and environmental shifts in functional diversity (FDiv). Functional diversity indices exhibited distinct seasonal patterns: FDiv peaked in summer, indicating niche differentiation, while functional evenness indicated a more even trait distribution in winter. RaoQ index and functional dispersion revealed higher diversity in autumn and summer under favorable conditions, whereas winter and spring were characterized by reduced diversity due to harsher environmental constraints. RLQ and fourth-corner analyses demonstrated that agricultural runoff and sedimentation significantly influenced EPT traits, particularly in spring and summer. Traits associated with tolerance to pollution and sediment-rich conditions increased, whereas stress-sensitive traits declined under elevated anthropogenic pressure. In contrast, weaker relationships in autumn and winter reflected relative environmental stability, favoring traits related to flow preference and oxygen acquisition. These findings highlight the value of trait-based approaches in detecting ecological responses to human disturbances and provide critical insights for biomonitoring and conservation strategies in Mediterranean river systems.

The effect of fire on the carbon fluxes and productivity of Brazilian woodland savannas

The effects of altered fire regimes within open ecosystems are poorly understood and can have serious consequences on functioning and conservation across savanna ecoregions worldwide. In South American savannas like the Cerrado, there is a gap of knowledge relating to carbon cycling in the presence of fire, meaning the impacts of altered fire regimes on the carbon fluxes and budgets are virtually unknown. We thus investigate vegetation carbon flux dynamics within the Cerrado making use of an experimental fire and carbon monitoring research project at the Estação Ecológica da Serra das Araras, Brazil. We present a thorough carbon budget of woodland-type savannas (cerrado sensu stricto), and investigate how annual (every year), biennial (every two years), and triennial (every three years) controlled fire frequencies have influenced net primary productivity and respiration fluxes. Six years of experimental fire had noticeable effects on the vegetation structure and carbon dynamics, reducing woody cover and productivity in favour of grass-dominated carbon balances. Woody NPP increased by 35 % in the unburnt plots from 2017 to 2019 to 2021-2023, but decreased by 75 %, 33 % and 20 % in the triennial, biennial and annual fire frequencies. By 2023, burnt plots revealed around three times higher herbaceous NPP than unburnt plots. Fluxes corresponding to different ecosystem components (canopy, stems, roots, herbs) showed varying patterns of change across the gradient of experimental fire frequencies, indicating other fire regime properties distinctively affect each vegetation segment. Fire intensity and severity appear to be linked with patterns in woody stems and the herbaceous layer. Our results indicate periodically burnt cerrado sensu stricto vegetation experiences different carbon dynamics than unburnt vegetation. Burning is revealed as a strategy that can successfully limit woody encroachment and help conserve open ecosystem structure in the Cerrado. Our study highlights the importance of long-term monitoring efforts in investigating the effects of management interventions and environmental shifts on ecosystem functioning.

Developmental toxicity and environmental risk assessment of chlorothalonil: A comprehensive study using biomphalaria as a model gastropod

The threat of pesticide pollution to aquatic ecosystems is severe. Chlorothalonil, a broad-spectrum fungicide, causes toxic effects on non-target organisms. While previous studies have focused on mussels, clams, and fish, research on gastropods remains limited despite their critical ecological roles. This study systematically evaluated the toxicity of chlorothalonil across different developmental stages of B. glabrata, with B. straminea (Red) adults serving as a comparative reference. Results showed that the median lethal concentration (LC50) was 0.3396 mg/L for B. glabrata embryos and 3.598 mg/L for adults, while the LC50 for B. straminea (Red) adults was 2.315 mg/L. Chronic exposure (21 days) to sublethal concentrations significantly inhibited shell growth, reduced egg production, and increased abnormal egg masses concentration-dependently. Histopathological analysis revealed severe tissue damage at 0.8 mg/L, including reduced hemocyte density, hepatopancreatic acinar disintegration, and ovotestis vacuolation. These findings provide critical evidence of chlorothalonil's environmental risks and emphasize the importance of evaluating pesticide effects on different developmental stages of non-target organisms.

Estimation of organic carbon source composition and riverine outflow using an integrated watershed hydrological-carbon modelling approach

Carbon source apportionment and outflow estimation are the primary scientific considerations for reducing carbon output from watershed ecosystems to ocean. However, carbon loss and transportation mechanisms from soil to river system driven by watershed hydrological cycle, remain unclear. Our study developed a process-based watershed organic carbon model that integrates soil biogeochemical processes, overland loss, riverine metabolism and transportation driven by hydrological processes, and estimates the sources, outflows and their spatial distributions. The proposed model was validated using long-term field observations of runoff and labile particulate, dissolved, and total organic carbon (LOC, DOC and TOC) loads across the Xiangxi Watershed in China. The biases within ±0.25 were for all runoff simulations and for 71.4 % (30/42) of carbon load simulations, and both Nash-Sutcliffe efficiency and correlation coefficient were over 0.60 for runoff simulation and for 83.3 % (35/42) of carbon load simulations. Annual average TOC load flowing into rivers was 11.3 ton.km-2.yr-1, with resistant particulate organic carbon (ROC) as the main form, accounting for 88.7 % of the TOC load. Atmospheric deposition was the primary TOC source with a contribution of 87.9 %, followed by soil loss. Annual average riverine TOC outflow was 3.8 ton.yr-1, with LOC and DOC accounting for 57.5 % and 40.0 %, respectively. This indicates that a majority of ROC decomposed into DOC and LOC via riverine metabolism and sedimentation. Our study provides insights into integration mechanisms of watershed hydrological and carbon cycles, and contributes to strategies for controlling water and carbon losses to strengthen terrestrial carbon sequestration.

Silver nanoparticles alter plankton-mediated carbon cycle processes in freshwater mesocosms

Understanding the ecological impacts of nanoparticle exposure has become increasingly urgent, as these materials are now widespread in aquatic environments. However, the effects of nanoparticle exposure on plankton community-mediated carbon cycling remain poorly understood. This study investigated the effects of long-term (28-day) exposure to environmentally relevant concentrations (10 and 100 µg/L) of silver nanoparticles (AgNPs) on the plankton-mediated carbon cycling processes of freshwater ecosystems by constructing a mesocosm ecosystem. The results showed that AgNP exposure enhanced the photosynthetic activity and biomass of both phytoplankton and zooplankton, thereby promoting carbon fixation. AgNP exposure also increased the ecological niche breadth and carbon source utilization of planktonic microorganisms while disrupting lipid metabolism, which facilitated carbon decomposition and utilization. Furthermore, AgNPs promoted the transformation of organic carbon by reducing the content and chemical composition of dissolved organic carbon and increasing the sedimentation of particulate organic carbon in the plankton community. Notably, compared with the control, exposure to 10 and 100 µg/L AgNPs reduced CO2 release at the water-air interface by 9 % and 17 %, respectively. Overall, this study provides the first evidence that long-term exposure to AgNPs can alter plankton-mediated carbon cycling processes in aquatic ecosystems, offering new insights into the ecotoxicological effects and risk assessment of nanoparticles.

Characteristics of microbial carbon pump in the sediment of kelp aquaculture zone and its contribution to recalcitrant dissolved organic carbon turnover: insights into metabolic patterns and ecological functions

The study delves into the microbial carbon pump (MCP) within the sediments of kelp aquaculture zones, focusing on its influence on the turnover of recalcitrant dissolved organic carbon (RDOC). Following kelp harvest, significant alterations in the microbial community structure were noted, with a decrease in complexity and heterogeneity within co-occurrence networks potentially impacting RDOC production efficiency. Metabolic models constructed identified four key microbial lineages crucial for RDOC turnover, with their abundance observed to decrease post-harvest. Analysis of metabolic complementarity revealed that RDOC-degrading microorganisms exhibit broad substrate diversity and are engaged in specific resource exchange patterns, with cross-feeding interactions possibly enhancing the ecological efficiency of the MCP. Notably, the degradation of RDOC was found not to deplete the RDOC pool; as aromatic compounds break down, new ones are released into the environment, thus supporting the renewal of the RDOC pool. The research highlights the pivotal role of microbial communities in RDOC turnover and offers fresh insights into their cross-feeding behavior related to RDOC cycling, providing valuable data to support the future development and application of MCP theory.

Microbial taxonomic diversity and functional genes mirror soil ecosystem multifunctionality in nonferrous metal mining areas

The pollution of metal ions triggers great risks of damaging biodiversity and biodiversity-driven ecosystem multifunctioning, whether microbial functional gene can mirror ecosystem multifunctionality in nonferrous metal mining areas remains largely unknown. Macrogenome sequencing and statistical tools are used to decipher linkage between functional genes and ecosystem multifunctioning. Soil samples were collected from subdams in a copper tailings area at various stages of restoration. The results indicated that the diversity and composition of soil bacterial communities were more sensitive than those of the fungal and archaeal communities during the restoration process. The mean method revealed that nutrient, heavy metal, and soil carbon, nitrogen, and phosphorus multifunctionality decreased with increasing bacterial community richness, whereas highly significant positive correlations were detected between the species richness of the bacterial, fungal, and archaeal communities and the multifunctionality of the carbon, nitrogen, and phosphorus functional genes and of functional genes for metal resistance in the microbial communities. SEM revealed that soil SWC and pH were ecological factors that directly influenced abiotic factor-related EMF; microbial diversity was a major biotic factor influencing the functional gene multifunctionality of the microbiota; and different abiotic and biotic factors associated with EMF had differential effects on whole ecosystem multifunctionality. These findings will help clarify the contributions of soil microbial diversity and functional genes to multifunctionality in degraded ecosystems.

Nutrient enrichment by high aquaculture effluent input exacerbates imbalances between methane production and oxidation in mangrove sediments

Frequent aquaculture activities introduce substantial nutrients into mangrove ecosystems; however, the impact of this nutrient enrichment on methane (CH4) emissions and the associated microbial communities remains largely unexplored. In this study, we used the static chamber method, combined with 16S rRNA-based, metagenomic sequencing and binning techniques, to investigate the emission patterns of greenhouse gases (GHGs), with a particular focus on CH4, in mangroves subjected to different levels of effluents. The results showed that the effluent input decreased the mineral protection of sediment carbon (C) pools and increased C loss by more than double. In particular, high effluent input increased CH4 emissions by 243.3 %. Random forest analysis revealed that changes in methanogens were an important factor in explaining the variation of CH4 emissions. Amplicon data showed that the proportion of methylotrophic methanogens increased after effluent input, and metagenomic binning further attributed this change to the adaptability of methylotrophic methanogens to the substances transporting by the effluent. The enhanced hypoxia in sediments resulting from effluent input promoted the transition of methanotrophic communities from aerobic to anaerobic types and made anaerobic oxidation of CH4 more reliant on sulfur reduction rather than nitrate reduction. The PLS model further revealed that the nutrients brought by effluent input stimulated an increase in DOC content which induced an imbalance between CH4 production and oxidation in sediments by facilitating methanogens but inhibiting methanotrophs, ultimately resulting in an increase in CH4 fluxes. These findings underscore the significance of mangroves receiving effluent input as critical consequent reactors, highlighting the necessity to consider effects of high nutrient enrichment by aquaculture effluent input on GHG emissions and blue C potential in mangroves.

Ecological impacts of treated effluent on multitrophic biodiversity and their interactions

The reuse of water, particularly treated effluent from wastewater treatment plants (WWTPs), is a crucial and sustainable strategy for mitigating water scarcity, especially in megacities with high water demand and limited resources. However, the ecological risks associated with effluent discharge into receiving waterbodies have gained significant global attention. Understanding the dynamic effects of WWTP effluent on multi-trophic groups and their interactions is essential for assessing ecological impacts in aquatic ecosystems and informing management strategies. In this study, we examined five taxonomic groups representing different trophic levels of the freshwater food web - bacteria (decomposers), algae (primary producers), zooplankton (primary consumers), and benthic macroinvertebrates and fish (predators) - across two rivers to elucidate ecological responses to WWTP effluent from a multi-trophic perspective. Our results revealed significant but variable biological responses among these groups, depending on river conditions and trophic level. In the nutrient-rich river, primary consumers (zooplankton) were most affected, whereas in the nutrient-poor river, primary producers (algae) exhibited the strongest responses primarily derived from environmental disturbances. Notably, interactions between environmental variables and taxa were highly diverse, with trophic dynamics influenced by both bottom-up and top-down processes in the nutrient-rich river, whereas bottom-up effects dominated in the nutrient-poor river. Furthermore, niche overlap in algae-zooplankton networks was higher in the nutrient-rich river than in the nutrient-poor river. This study underscores the importance of integrating multi-trophic biodiversity profiling and trophic interaction analyses to comprehensively assess the ecological effects of WWTP effluent in receiving aquatic ecosystems with contrasting environmental contexts. Our findings highlight the importance of conservation and sustainable management practices, especially in urban aquatic ecosystems located in (semi-)arid regions that experience prolonged periods of low precipitation.

Functional insights into microbial community dynamics and resilience in mycorrhizal associated constructed wetlands under pesticide stress

Arbuscular mycorrhizal fungi (AMF) are critical mutualistic symbionts in most terrestrial ecosystems, where they facilitate nutrient acquisition, enhance plant resilience to environmental stressors, and shape the surrounding microbiome. However, its contributions (especially for microorganisms) to constructed wetlands (CWs) under pesticide stress remain poorly understood. This study investigated the effects of AMF on microbial community composition, diversity, metabolic pathways, and functional genes by metagenomics in CWs exposed to pesticides stress. Using comparative analyses of AMF-colonized and non-colonized CWs, we found that AMF enhanced overall microbial diversity, as evidenced by increases of 2.22 % (Chao1) and 2.83 % (observed species). Under fungicide stress, nitrogen-cycling microorganisms (e.g., Nitrososphaerota and Mucoromycota) increased in relative abundance, while carbon cycle-related microorganisms (e.g., Pseudomonadota and Bacteroidota) generally declined. AMF colonization improved microbial resilience, demonstrated by a 312 % rise in Rhizophagus abundance and significant increases in phosphorus-cycling microorganisms (e.g., Bradyrhizobium and Mesorhizobium). Functional gene analysis further revealed that AMF helped mitigate fungicide-induced reductions in genes related to nitrogen and carbon cycling, lowering the average decline rates to 4.02 % and 1.44 %, respectively, compared to higher rates in non-AMF treatments. In summary, these findings highlight the crucial role of AMF in enhancing pesticide stress resilience, maintaining microbial community stability, and improving the bioremediation capacity of CWs.

Floating-leaved and submerged macrophytes suppress filamentous cyanobacteria blooms and 2-MIB episodes in eutrophic shallow lakes

Although macrophytes can control filamentous cyanobacteria that produce 2-methylisoborneol (2-MIB) in lakes, there is a lack of evidence regarding the inhibitory effects of different macrophyte growth forms on 2-MIB producers, as well as the underlying mechanisms. To address this knowledge gap, this study compared the impact of floating-leaved and submerged macrophytes on Pseudanabaena growth and 2-MIB release, combing a field investigation and culture experiments. The field survey showed that both the Pseudanabaena cell density and 2-MIB concentrations were significantly lower in areas dominated by floating-leaved or submerged macrophytes than in phytoplankton-dominated areas. In the culture experiments, floating-leaved macrophytes exhibited overall stronger inhibitory effects on Pseudanabaena than submerged macrophytes. Allelopathic effects emerged as a more critical mechanism than nutrient competition and light limitation in controlling Pseudanabaena growth and 2-MIB release by regulating the photosynthetic activity, gene abundance, and cell density. Allelopathic experiments further confirmed that the dissolved organic matter released from Nymphoides peltate, Trapa bispinosa and Myriophyllum spicatum contained higher concentrations of allelochemicals than that released from Vallisneria natans and Ceratophyllum demersum, driving the photosynthetic inhibition pathway. These findings demonstrate that biological control has great promise as an effective method for odorant management in eutrophic shallow lakes.

Extinctions as a vestige of instability: The geometry of stability and feasibility

Species coexistence is a complex, multifaceted problem. At an equilibrium, coexistence requires two conditions: stability under small perturbations; and feasibility, meaning all species abundances are positive. Which of these two conditions is more restrictive has been debated for many years, with many works focusing on statistical arguments for systems with many species. Within the framework of the Lotka-Volterra equations, we examine the geometry of the region of coexistence in the space of interaction strengths, for symmetric competitive interactions and any finite number of species. We consider what happens when starting at a point within the coexistence region, and changing the interaction strengths continuously until one of the two conditions breaks. We find that coexistence generically breaks through the loss of feasibility, as the abundance of one species reaches zero. An exception to this rule - where stability breaks before feasibility - happens only at isolated points, or more generally on a lower dimensional subset of the boundary. The reason behind this is that as a stability boundary is approached, some of the abundances generally diverge towards minus infinity, and so go extinct at some earlier point, breaking the feasibility condition first. These results define a new sense in which feasibility is a more restrictive condition than stability, and show that these two requirements are closely interrelated. We then show how our results affect the changes in the set of coexisting species when interaction strengths are changed: a system of coexisting species loses a species by its abundance continuously going to zero, and this new fixed point is unique. As parameters are further changed, multiple alternative equilibria may be found. Finally, we discuss the extent to which our results apply to asymmetric interactions.

Global distribution characteristics and ecological risk assessment of microplastics in aquatic organisms based on meta-analysis

As microplastic pollution in the natural environment intensifies, the risk of microplastic contamination faced by aquatic organisms has garnered increasing widespread attention. Most studies have primarily focused on the impacts of microplastics within specific regions and on particular species. However, with the global migration of microplastics, it is necessary to conduct comprehensive research on the distribution characteristics, ingestion mechanisms, and ecological impacts of microplastics across various aquatic organisms. To address this research gap, the present study systematically evaluates the distribution status of microplastics in global aquatic organisms and assesses their potential ecological risks. Firstly, a review of the sources and impacts of microplastics within aquatic organisms is provided. Secondly, a bibliometric analysis is employed to examine the current research landscape and trends, coupled with a quantitative analysis of how the biological characteristics of aquatic organisms influence microplastic ingestion and the distribution patterns of microplastics within these organisms. Thirdly, the study investigates the mechanisms by which microplastics affect aquatic food chains by examining their impact on organisms at different trophic levels. Finally, strategies to reduce microplastic input into water bodies and future research directions are proposed. The findings offer scientific foundations and decision-making support for global microplastic pollution control, aiming to protect the health and sustainable development of aquatic ecosystems.

Environmental gradient changes shape multi-scale food web structures: Impact on antibiotics trophic transfer in a lake ecosystem

Environmental change can alter the multi-scale foodweb structure, thereby impacting the pollutants trophic transfer in aquatic ecosystems. However, a quantitative understanding of how environmental gradient changes affect pollutant trophic transfer in natural lake ecosystems remains limited. This study investigated temporal variations in environment change index (ECi), multi-scale foodweb structure, and trophic transfer of quinolones antibiotics (QNs) in Baiyangdian Lake, Northern China, from 2018 to 2023. Our results demonstrated that the interaction strength (IS) in detritus (DIS) and macrophyte (MIS) in 2023 were significantly lower than those in 2018, and diversity indices exhibited significant temporal differences between 2018 and 2023. ECi was significantly correlated with DIS/MIS between species at the population scale and with diversity indices (DH and H') at the ecosystem scale. The trophic magnification factors (TMFs) of QNs have higher values in 2023 compared to 2018, showing significant temporal differences. Through structural equation model, the results showed ECi directly impacted DIS, which in turn affected SEAc and H', while indirectly influencing TMFs. The TMFs of QNs was mainly regulated by environmental factors. These findings highlighted the influencing mechanism through multi-scale foodweb structures regulate pollutant trophic transfer under environmental change in natural lake.

Polystyrene nanoparticles intensify the algae-mediated negative priming effect on leaf litter decomposition

The potential threat of nanoplastics on the heterotrophic decomposition of leaf litter lies in their impact on microbial activity and community structure in streams. Therefore, it is crucial to understand the interactions between benthic algae and microbial decomposers when assessing the functioning of stream ecosystems. However, the potential influence of benthic algae on the response of heterotrophic decomposers to nanoplastics remains unknown. This study investigated the interactions between benthic algae and heterotrophic microbial decomposers in the presence of polystyrene nanoparticles (PS-NPs), focusing on their role in leaf litter decomposition and nutrient cycling. The microcosm experiment demonstrated a negative priming effect of benthic algae on leaf decomposition in the absence of PS-NPs. In contrast, the algae-mediated negative priming effect was significantly intensified under PS-NP exposures, decreasing the decomposition rate by 21.3 %. During the various ecological processes, PS-NP exposures significantly reduced the algal biomass and dissolved organic carbon, which in turn disrupted the transfer of labile carbon from benthic algae to heterotrophic microbial decomposers and consequently impeding leaf decomposition process. Additionally, the synergistic effect of benthic algae and PS-NPs decreased the fungal diversity and undermined the dominance of functional genera (i.e., Setophaeosphaeria and Tetracladium) within the microbial decomposer community. In summary, this study offers innovative insights into the interactions among microbial communities colonizing streambed substrates under plastic pollution, highlighting the ecological implications of nanoplastic detrimental influences on aquatic ecosystems.

Niche differentiation shaped the evolution of rhizobacterial antibiotic resistance in paddy fields: Evidences from spatial-temporal and chemical-biological scaling

The rhizosphere serves as both a hotspot and an entry point for the proliferation and transformation of antibiotic resistance genes (ARGs). However, the ecological mechanisms governing the evolution of ARGs in rhizosphere soils remain poorly understood. This study showed that ARGs associated with efflux pumps were found to be significantly enriched in the rice rhizosphere, compared to bulk soils, with a deterministic assembly process. Notably, soil habitat specialization, dominated by turnover processes and the accelerated succession of microbial evolution in rhizosphere soils, profoundly influenced the spatial-temporal composition and expression of ARGs. Furthermore, ARGs involved in carbohydrate and proton transport showed higher activity in the rhizosphere, conductive to the adaptation of chemical niche differentiation. The genetic-level impacts stemming from biological niche warfare significantly shaped the evolutionary trajectory of ARG. Overall, rhizosphere effects led to 20.2-41.3 % of ARGs been enriched or depleted across various rice growth and under different irrigation conditions. These findings offer a comprehensive understanding of the essential ecological roles of ARGs evolution in rhizosphere soils, which is critical for ARGs risks analysis in the context of plant recruitment and growth promotion.

Navigating stress: Impacts of temperature, polycyclic aromatic hydrocarbons, and heavy metals on the diatom Thalassiosira weissflogii adapted to tropical waters of the Gulf of Guinea

This study evaluated the individual and combined impacts of temperature, pyrene, and cadmium on the coastal diatom Thalassiosira weissflogii under conditions representative of the Gulf of Guinea. In the individual stressor experiments, time, rather than temperature or individual pollutants, was the primary factor influencing growth parameters. Specifically, temperature modulated diatom growth with optimal performance at 28 °C, while 24 °C and 32 °C conditions reduced cell density, chlorophyll-a content, and dry biomass. On the other hand, pyrene significantly affected cell density and dry biomass, while cadmium elicited minimal effects on all measured parameters. In combined stressor experiments, the negative impacts of pyrene and cadmium combinations were more exacerbated at 24 °C and 32 °C, whereas optimal thermal conditions (28 °C) provided partial mitigation from exposure to stressors. These findings highlight the crucial role of temperature in modulating the effects of pollutants on Thalassiosira weissflogii, with combined stress having the greatest impact under non-optimal temperature conditions. Additionally, the study underscores the temperature sensitivity of Thalassiosira weissflogii in tropical ecosystems and offers insights into how the simultaneous stressors of rising ocean temperatures and increasing pollution may affect tropical phytoplankton dynamics and primary productivity. Lastly, the study emphasizes the importance of incorporating thermal thresholds into marine ecosystem models to more accurately predict shifts in coastal and oceanic food webs under climate change scenarios.

Impact of heterogeneity on infection probability: Insights from single-hit dose-response models

The process of infection of a host is complex, influenced by factors such as microbial variation within and between hosts as well as differences in dose across hosts. This study uses dose-response and within-host microbial infection models to delve into the impact of these factors on infection probability. It is rigorously demonstrated that within-host heterogeneity in microbial infectivity enhances the probability of infection. The effect of infectivity and dose variation between hosts is studied in terms of the expected value of the probability of infection. General analytical findings, derived under the assumption of small infectivity, reveal that both types of heterogeneity reduce the expected infection probability. Interestingly, this trend appears consistent across specific dose-response models, suggesting a limited role for the small infectivity condition. Additionally, the vital dynamics behind heterogeneous infectivity are investigated with a within-host microbial growth model which enhances the biological significance of single-hit dose-response models. Testing these mathematical predictions inspire new and challenging laboratory experiments that could deepen our understanding of infections.

Rhizosphere metabolite dynamics in continuous cropping of vineyards: Impact on microflora diversity and co-occurrence networks

The metabolism of the crop rhizosphere affects microflora diversity and nutrient cycling. However, understanding rhizosphere metabolism in suitable crops within arid desert environments and its impact on microflora interactions remains limited. Through metagenomic and non-targeted metabolomic sequencing of rhizosphere soils from one uncultivated land and four vineyards with cropping years of 5, 10, 15 and 20 years, the critical importance of rhizosphere metabolites in maintaining bacterial and fungal diversity was elucidated. The results revealed that Nocardioides, Streptomyces, and Solirubrobacter were the relatively abundant bacterial genera in rhizosphere soils, while Rhizophagus, Glomus, and Pseudogymnoascus were the relatively abundant fungal genera. The composition of rhizosphere metabolic changed significantly during the continuous cropping of grapevines. Dimethylglycine, Formononetin, and Dehydroepiandrosterone were the most important metabolites. Enrichment analysis revealed significant involvement of metabolic pathways such as biosynthesis of amino acids, unsaturated fatty acids, and linoleic acid metabolism. Procrustes analysis highlighted stronger correlations between rhizosphere metabolites and bacterial community compared to those of fungal community. This suggests distinct responses of microflora to crop-released chemical elements across different soil habitats. Co-occurrence network analysis demonstrated complex associations between rhizosphere metabolites and soil microflora, the positive correlations between rhizosphere metabolites and microflora networks predominated over negative correlations. Partial least squares path model indicated that the effect of cropping years on rhizosphere metabolites was greater than that on bacterial microflora diversity. Futhermore, pH, total phosphorus, and alkali-hydrolyzed nitrogen were the key environmental factors affecting rhizosphere metabolites and microbial diversity. These results deepen our valuable insights into the complex biological processes that rhizosphere metabolites influence on microorganisms, and provide strong support for maintaining microbial diversity in farmland soils in arid regions.

Ocean acidification disrupts the energy balance and impairs the health of mussels (Mytilus coruscus) by weakening their trophic interactions with microalgae and intestinal microbiome

Despite extensive research in the last two decades, exploring the potential mechanisms underlying the sensitivity and resistance of marine organisms to ocean acidification is still imperative. Species interactions can play a role in these mechanisms, but the extent to which they modulate organismal responses to ocean acidification remains largely unknown. Here, we investigated how ocean acidification (pH 7.7) affects energy homeostasis and fitness of mussels (Mytilus coruscus) by assessing their physiological responses, intestinal microbiome and nutritional quality of their food (microalgae). Under ocean acidification, the mussels had reduced feeding rates by 34 % and reduced activities of digestive enzymes (pepsin by 39 %, trypsin by 28 % and lipase by 53 %) due to direct exposure to acidified seawater and increased phenol content of microalgae. Richness and diversity of intestinal microbiome (OTU, Chao1 index and Shannon index) were also lowered by ocean acidification, which can undermine nutrient absorption. On the other hand, energy expenditure of mussels increased by 53 % under ocean acidification, which was associated with the upregulation of antioxidant defence (SOD, CAT and GPx activities). Consequently, energy reserves in mussels decreased by 28 %, which were underpinned by the reduction in protein, carbohydrate and lipid contents. Overall, we demonstrate that ocean acidification could disrupt herbivore-algae and host-microbe interactions, thereby lowering the energy balance and impairing the health of marine organisms. This can have ramifications on the population and energy dynamics of marine communities in the acidifying ocean.

Environmental strategies increase the resilience of extensive livestock systems to adverse climate conditions

This study presents an agent-based model to assess the resilience and ecological, economic, and social sustainability of three extensive livestock system archetypes: subsistence, commercial, and environmental. Subsistence focuses on traditional practices, commercial prioritizes profit, and environmental emphasizes resource conservation and animal welfare. The model simulates livestock dynamics under two grazing strategies (free and rotational grazing) under thirty climate-driven primary productivity change scenarios as a proxy to explore the potential long-term and persistent impacts of climate change. Results indicate that all archetypes reach a collapse threshold under extreme climate conditions, and that no single strategy performs best under all circumstances. The environmental performs best under adverse but non-critical conditions, especially in ecological sustainability; the subsistence is the most vulnerable and the commercial excels in economic and social sustainability under favorable conditions. Under normal or favorable climate-driven conditions, tradeoffs between sustainability dimensions emerge. Rotational grazing improves ecological sustainability, but reduces economic and social performance. Strategies to reduce tradeoffs are essential to improve the ecological footprint of commercial systems and the economic viability of environmental systems under changing climates. This model has the potential to be transferable and adaptable to a wide range of extensive livestock systems, providing a valuable tool for research and policy aimed at building climate-resilient pastoral systems.

Intensive oyster farming alters the microbial-regulated blue carbon storage in sediment

Intensive oyster farming enhances the organic matter coupling from water to sediment through biodeposition, potentially contributing to carbon storage. Microbes play a key role in regulating biogeochemical cycling in the coastal sediment. However, their specific contributions to carbon storage under oyster farming remain poorly understood. This study investigates microbial necromass and associated biogeochemical processes in sediments from an intensive oyster farm in Sanggou Bay, China, and compares these indicators with adjacent seagrass beds and bare zones. Additionally, carbon use efficiency (CUE) was employed to indicate microbial-regulated carbon cycling and storage in sediment. The results demonstrate that oyster farming promotes organic carbon accumulation in surface sediments but reduces its stability. Microbial necromass was identified as a critical driver of sedimentary organic carbon in oyster farm sediments, supported by enhanced nitrogen and sulfur cycling pathways. Notably, contrasting relationships between CUE and organic carbon were observed between the seagrass bed and the oyster farm. Functional metagenomic analysis further revealed distinct microbial metabolic pathways across habitats, highlighting the role of biodeposition in shaping microbial functions. These findings enhance our understanding of microbial contributions to blue carbon storage in aquaculture systems and provide new insights into coastal carbon storage beyond vegetated ecosystems.

Cones and consequences: the false dichotomy of conifers vs broad-leaves has critical implications for research and modelling

In plant science research and modelling, particularly from the northern hemisphere, the terms 'needle-leaved' and 'conifer' along with 'broad-leaved' and 'angiosperm' are often used synonymously, creating the false dichotomy that conifers are needle-leaved and angiosperms are broad-leaved. While these equivalences may be largely correct in the temperate northern hemisphere, they do not hold true in equatorial and southern hemisphere forests. Confounding needle-leaved conifers and broad-leaved angiosperms presents significant issues in empirical research and modelling. Here, we highlight the likely origins and impacts of misusing conifer-related terminology, the misinterpretation that ensues and its implications. We identify the issue of a focus on Pinaceae and coin the term 'Pinaceae panacea' to describe this. We provide recommendations for future research: from standardising the use of definitions to shifting away from using Pinaceae as a model group for all conifers.

Multiscale agrobiodiversity conservation: modeling epigaeic arthropod diversity with landscape heterogeneity and ecosystem services

Agricultural landscape heterogeneity and ecosystem services are inextricably linked to emerging biodiversity patterns, while landscape design and ecosystem service regulation serve as effective strategies for biodiversity conservation. This study constructed ecological models integrating landscape variables, ecosystem services, and epigaeic arthropod diversity across three scales: field, watershed and county. The independent and combined effects of landscape composition, configuration and various types of ecosystem services on epigaeic arthropods, as well as the scale heterogeneity of these effects, were analyzed. The results showed that ecosystem services significantly increased the explanatory power of landscape variables on epigaeic arthropod diversity and mediated the influence of landscape heterogeneity on epigaeic arthropod diversity. At the watershed scale, the influence of forest occupancy on epigaeic arthropod diversity was indirectly mediated by ecosystem services such as habitat quality, carbon sequestration and water yield. The effects of landscape composition, landscape configuration, and ecosystem services on epigaeic arthropod diversity exhibited scale-dependent heterogeneity. At the county scale, landscape heterogeneity played a stronger role in explaining epigaeic arthropod diversity, while at the watershed scale, the mediating influence of ecosystem services was more pronounced. This study provides a scientific foundation for designing multi-level and multi-scale landscape planning and ecosystem management strategies.

Quantifying microbial necromass contributions to soil carbon sequestration under diverse cropland management practices: A meta-analysis

Under the dual challenges of global climate change and agricultural sustainability, cropland soils, as critical carbon (C) sinks, have garnered significant attention regarding the stabilization mechanisms of their organic C pools. Existing studies indicate that the stable organic C pool in cropland soils primarily originates from the accumulation of microbial necromass, a process strongly influence by agricultural management practices. However, there remains a notable knowledge gap regarding how various management strategies influence microbially turnover and necromass formation mechanisms. This study integrates 1082 globally distributed paired experimental datasets to establish the quantitative framework linking microbial necromass dynamics with multi-scale management practices. The results showed that the greatest increase in microbial necromass C (MNC) content (42 %) was obtained when mineral and organic fertilizers were combined. Individually, the application of manure, straw, and green manure boosted MNC by 28 %, 9 %, and 31 %, respectively. Conservation tillage and crop rotation increased MNC by 20 % and 14 %, respectively. A pivotal advancement lies in elucidating the lagged formation of microbial necromass relative to living biomass turnover and demonstrating the superior coupling effects of integrated management strategies over singular practices. Interactions among climatic, soil physicochemical and microbial properties regulated the necromass formation pathways and organic C accumulation. Appropriate management strategies can boost C sequestration in cropland soils by facilitating microbial necromass accumulation, offering potential benefits at both regional and global scales.

Resilience response of China's terrestrial ecosystem gross primary productivity under environmental stress

Climate change perturbations contribute to the alteration of ecosystem functions and the reduction of their resilience. Understanding this reduction in resilience is fundamental for formulating strategies for sustainable ecosystem management. Consequently, a systematic evaluation of factors influencing ecosystem resilience is imperative. This involves elucidating the resilience trends and stress conditions within Chinese ecosystems spatially, thereby enabling a holistic assessment of their health status. This study assesses resilience across China by analyzing the one-month lagged time autocorrelation of terrestrial Gross Primary Production (GPP) across China. It differentiates between various stress states within the study region and employs interpretable machine learning methods to examine the relationship between terrestrial ecosystem resilience and environmental changes under different stress conditions. The findings reveal that approximately 20 % of Chinese regions are undergoing a decrease in ecosystem resilience, with over half experiencing stressed conditions. This is particularly pronounced in the northeastern and central regions of China, where a more significant and widespread decrease in resilience is observed. In the stressed areas of China, the effect of each environmental factor on the decrease in resilience is greater, where attention needs to be paid to areas with higher maximum temperature, precipitation, vapor pressure deficit, and radiation. The study highlights the variability in ecosystem resilience under different environmental conditions and their varied responses to environmental changes. This provides a scientific basis for protecting ecological balance and promoting the sustainable development of ecosystems.

Mycorrhizal fungi drive Cd and P allocation strategies for the co-planting system of hyperaccumulator S. nigrum and upland rice

Arbuscular mycorrhizal fungi (AMF) enhance the remediation potential of hyperaccumulator-crop co-planting systems, yet the mechanisms governing cadmium (Cd) and phosphorus (P) allocation remain unclear. To investigate these strategies, pot experiments were conducted using Cd-contaminated soil (1.0 mg kg-1 Cd) where the Cd hyperaccumulator Solanum nigrum (S. nigrum) was intercropped with upland rice under Funneliformis mosseae inoculation. Rhizospheric GRSP content, Cd/P allocation patterns, and microbial community structure were analyzed using in situ analysis using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), sequential chemical extraction, and 16S rRNA sequencing. Results showed that AMF increased total Cd accumulation in S. nigrum shoots by 25.37 % while reducing Cd uptake in rice shoots and roots by 45.18 % and 55.54 %, respectively. AMF also enhanced the P uptake rate of S. nigrum by 1.76 times compared to non-inoculated conditions, thereby increasing the total P accumulation in S. nigrum by 25.62 % under Cd stress. Conversely, AMF negatively impacted the P content and total P accumulation in neighboring rice. Rhizospheric GRSP content increased significantly, indicating AMF's role in reducing Cd availability for rice. In situ analysis of LA-ICP-MS confirmed lower Cd content in rice rhizosphere and root surfaces, with minimal effects on S. nigrum. Lower DTPA-Cd concentrations in the rhizosphere of intercropped rice further substantiated the mycorrhizal Cd-blocking effects of AMF. Furthermore, AMF inoculation was the principal factor influencing alterations in the bacterial community structure within the intercropping system, by increasing the abundance of phosphate-solubilizing bacteria (mainly Ramlibacter, Roseisolibacter, and Bacillus) in the rhizosphere. AMF reduced the relative abundance of metal-tolerant bacteria (primarily Flavisolibacter) in the S. nigrum rhizosphere while enhancing their presence in the rice rhizosphere. This work revealed the resource acquisition effect (especially P uptake) of AMF on S. nigrum, thereby promoting Cd uptake and its preferential strengthening of the Cd-defending effect of the intercropped rice.

Vegetation succession enhances microbial diversity, network complexity, and stability in coastal wetlands, underscoring the pivotal role of soil salinity and key microbial species

In coastal wetlands, vegetation succession is primarily driven by changes in hydrology, sedimentation, and soil salinity. This ecological process is known to significantly influence microbial communities. However, its specific effect on microbial interactions and network dynamics in coastal wetlands remains insufficiently understood. This study adopted a spatial ecological sequence approach instead of a temporal succession method to comprehensively analyze the effects of vegetation succession on microbial communities in the Yellow River Delta. The results demonstrated that soil salinity, rather than nutrient levels, was the primary driver of microbial community shifts during succession. Succession increased the relative abundance of dominant phyla, such as Acidobacteria, Actinobacteria, Chloroflexi, and Planctomycetota, whereas key taxa, including salt-tolerant species, functioned as pivotal nodes regulating community interactions. Co-occurrence network analysis revealed that vegetation succession significantly enhanced the complexity and stability of microbial networks by reducing soil salinity and thereby altering the composition of key microbial taxa. These findings reveal the salinity-mediated mechanisms underlying microbial network assembly during vegetation succession in coastal wetlands and identify environmentally responsive microbial taxa that act as critical connectors within microbial communities, providing a mechanistic basis for the ecological restoration and sustainable management of salinized coastal ecosystems.

Effects of substrate materials on microbial diversity and network dynamics: Comparing microplastics and silica-based materials

Attached microbes play a crucial role in the degradation of pollutants and microplastics within lake ecosystems. However, it remains poorly understood how different substrate materials affect the diversity and co-occurrence patterns of attached microbes. Here, a 70-day mesocosm experiment was conducted using three types of silicon-based materials and two types of microplastics as substrates. The successional dynamics of attached bacterial communities were characterized using 16S rRNA gene sequencing. Our results revealed significant differences in the bacterial community composition and structure between the silica-based material (SG) and microplastic (MP) groups (Adonis, P < 0.001). Among them, bacterial diversity in the MP group was significantly lower than that in the SG group and exhibited a declining trend during the late stage of attachment. Random forest analysis indicated that the dominant bacterial communities in the MP group were relatively simpler than those in the SG group. In the MP group, Stenotrophomonas and Methyloversatilis dominated the early stage of attachment, followed by Brevundimonas in the middle stage. In the late stage, genera such as CL500-29_marine_group, Parviterribacter, and Phreatobacter co-dominated the community structure. Furthermore, substrate materials significantly influenced the co-occurrence network patterns of attached bacterial communities. Specifically, the SG group exhibited an initial decrease followed by an increase in network complexity over time, whereas the MP group showed the opposite trend. Network stability was significantly higher in the SG group than in the MP group, with both groups demonstrating a temporal pattern of initial increase followed by a decrease. Overall, these findings provide new insights into the responses of attached microbes to different substrate materials, the evolution of network complexity and stability. Our study could inform ecological management strategies for mitigating microplastic pollution and regulating attached microbial communities.

Beyond taxonomy: A functional approach reveals patterns of reef fish response to wastewater pollution

Coral reefs face severe threats from climate change and local stressors like wastewater pollution, which significantly impact reef ecosystems but remain underexplored. Reef fish are essential for supporting human livelihoods through fisheries and maintaining ecosystem functions such as nutrient cycling and algae control. While most research focuses on wastewater's effects on benthic communities, its impact on reef fish physiology, behavior, and community structure is poorly understood. Few studies apply trait-based approaches to evaluate wastewater's influence on fish's ecological roles. This study systematically reviews 52 papers and conducts a meta-analysis of eight control-impact studies to assess wastewater effects on reef fish taxonomic and functional structure. Taxonomy-based metrics revealed mixed responses, with studies reporting declines, increases, or no changes in abundance, richness, and biomass in polluted sites. Functional analysis provided clearer patterns: polluted sites were dominated by smaller, high-resilience species at mid-trophic levels, while control sites supported larger, low-resilience species at diverse depths and trophic levels. Functional richness was generally higher in control sites. Pollutant-specific effects varied: sediments impaired feeding efficiency and growth, while nutrient enrichment shifted species composition by favoring lower trophic levels. These findings demonstrate the limitations of taxonomy-based metrics and highlight the value of functional approaches for detecting early ecosystem degradation. Integrating functional ecology with wastewater characterization enhances predictions of ecological responses and supports targeted management strategies. This research emphasizes the urgency of addressing wastewater pollution to safeguard reef biodiversity and ecosystem services critical to human well-being.

Greening of grey and murky harbours: enhancing biodiversity and ecosystem functioning on artificial shorelines

Shoreline armouring in coastal cities can cause habitat degradation and biodiversity loss, often exacerbated by common anthropogenic stressors. Boulders are used as riprap to create revetments walls; but the homogenous surface and absence of shelter reduces intertidal biodiversity and ecosystem functioning. Eco-engineering can mitigate habitat loss through the addition of water retention and other microhabitats. We deployed four eco-engineered designs in a degraded harbour riprap for 18 months. Two units with site-specific designs combined multiple microhabitat types, attracting the highest species diversity. All four designs generally increased within-site β diversity and fish diversity compared to nearby unmanipulated ripraps. Suspension-feeding species and more species within key functional groups colonised eco-engineered units at patch and site scale. Tailored, site-specific eco-engineering shows great potential to rehabilitate degraded ripraps into functional, novel ecosystems. Combining eco-engineering with anthropogenic stress reduction to enable recovery can enhance biodiversity and ecosystem functioning in coastal cities.