Richness Index Research Articles

Influence of different stocking densities of pearlspot (Etroplus suratensis) on plankton diversity indices of biofilm-based rearing system

Aim: Biofilm-based aquaculture systems, proven cost-effective, reduce the need for expensive supplementary feed. The biofilm acts as a natural planktonic food source for reared organisms. Previous research highlighted the influence of fish stocking density and biomass on plankton diversity in different aquaculture settings, underscoring the significance of these factors in biofilm-based systems. Hence, the present study attempted to understand how varying stocking densities of pearlspot (Etroplus suratensis) influence plankton diversity indices in the biofilm-based aquaculture system. Methodology: The present experiment was designed in 5 Practical Salinity Unit (PSU) brackishwater with soil-bottomed FRP circular (500 L) tanks for 60 days. The sugarcane bagasse was used as a substrate forbiofilm production after fertilization with cow dung, urea, and lime. Fries of pearlspot (4.67 ± 0.04 mm 1.71 ± 0.03 g-1) were stocked at four different stocking densities in triplicates viz T1 (50 nos); T2 (100 nos), T3 (150 nos) and T4 (200 nos) fish fry m-3 in the biofilm-based rearing system. Plankton samples were collected from water and biofilm deposited on the substrate and analyzed for diversity indices. The Shannon Diversity Index, Simpson Diversity Index, Simpson Dominance Index, and Margalef Richness Index were used to compute the plankton diversity indices in different treatments using standard equations. Results: In the current investigation, lower stocking densities with lower fish biomass were associated with significantly higher (P≤0.05) Shannon Diversity Index, Simpson Diversity Index, and Margalef Richness Index in water. In contrast, the Simpson Dominance Index in water showed a significantly lower (P≤0.05) value for treatments with lower fish biomass than for treatments with higher biomass. Interpretation: The values obtained for various diversity indices indicated that a biofilm-rearing system with lower E. suratensis biomass produced more planktonic abundance, evenness, and species richness. Key words: Biofilm, Pearlspot, Plankton diversity, Stocking density

Comparing diversity and structure of freshwater fish assemblages using environmental DNA and gillnetting methods: A case study of a large deep reservoir in East China

Environmental DNA (eDNA) technology, as an alternative to traditional gillnet surveys, has attracted widespread attention. However, comparisons between eDNA and traditional methods regarding biodiversity and community structure have not yet been fully elucidated. This study compared the ability of eDNA and gillnets for fish monitoring in a large deep reservoir (Qiandao Lake) in East China. The results showed that eDNA exhibited higher taxonomic resolution and detection rates, and significantly larger species diversity and richness indices compared with traditional gillnetting methods. Using abundance and biomass datasets from gillnets revealed significant differences in fish community composition between gillnetting and eDNA survey methods. Gillnet abundance was dominated by small-sized fish species, while gillnet biomass was dominated by larger-sized ones, and the prevailing species detected in eDNA reads included the dominant species from gillnet abundance and biomass, as well as a medium-sized invasive alien fish (Lepomis macrochirus). Non-metric multidimensional scaling (NMDS) showed that the spatial distribution in abundance of fish species sampled by gillnetting was more dispersed than that using eDNA. The explanatory power with the gillnet abundance and biomass together as predictor variables of the eDNA reads increased moderately compared with taking them separately, and the fitting degree of quadratic functions was also improved somewhat compared to linear equations when using biomass to predict eDNA reads. Furthermore, the key environmental factors affecting fish communities differed between the two methods. Current research indicates that eDNA has advantages over gillnets in detecting fish species diversity, and it is recommended to combine it with traditional sampling methods. Under natural aquatic ecosystem conditions, the eDNA reads may comprehensively reflect the biomass and abundance information obtained through gillnetting, but their relationship is complex and requires further research. This study will provide guidance for biodiversity monitoring.

Nature-based bank protection measures improve benthic macroinvertebrates in a stream draining an agriculturally dominated watershed

Increased bank erosion is one of the most significant threats to agricultural stream ecosystems. However, it is challenging to ascertain whether bank restoration measures positively affect in-stream habitats and aquatic communities. This study evaluated three nature-based bank protection measures' short-term (2-year) effects on aquatic physical habitat quality and benthic macroinvertebrate communities in a headwater stream in agricultural areas. The results demonstrate that nature-based bank protection measures can significantly improve the quality of aquatic physical habitat in streams. The TPRW (timber piles + riprap + willow cuttings) and WTRW (waste tires + riprap + willow cuttings) measures exhibited the most pronounced improvement in the quality of aquatic physical habitat in streams. The diversity of benthic macroinvertebrates was the highest in the TPRW reach, and the seasons significantly affected the density of benthic macroinvertebrates. The Shannon-Wiener diversity index and Margalef's richness index were the most consistent with the changing trend of physical habitat quality and are effective indicators of the ecological effects of stream restoration measures in our study area. In this study area, TPRW is the preferred measure for streambank restoration of agricultural streams, and WTRW is the alternative measure. However, the ecological effects of WTRW need to be monitored over a more extended period to identify whether there is potential ecotoxicity in the process of weathering and decomposition.

Structural and functional bacterial biodiversity in a copper, zinc and nickel amended bioreactor: shotgun metagenomic study

BackgroundAt lower concentrations copper (Cu), zinc (Zn) and nickel (Ni) are trace metals essential for some bacterial enzymes. At higher concentrations they might alter and inhibit microbial functioning in a bioreactor treating wastewater. We investigated the effect of incremental concentrations of Cu, Zn and Ni on the bacterial community structure and their metabolic functions by shotgun metagenomics. Metal concentrations reported in previous studies to inhibit bacterial metabolism were investigated.ResultsAt 31.5 μM Cu, 112.4 μM Ni and 122.3 μM Zn, the most abundant bacteria were Achromobacter and Agrobacterium. When the metal concentration increased 2 or fivefold their abundance decreased and members of Delftia, Stenotrophomonas and Sphingomonas dominated. Although the heterotrophic metabolic functions based on the gene profile was not affected when the metal concentration increased, changes in the sulfur biogeochemical cycle were detected. Despite the large variations in the bacterial community structure when concentrations of Cu, Zn and Ni increased in the bioreactor, functional changes in carbon metabolism were small.ConclusionsCommunity richness and diversity replacement indexes decreased significantly with increased metal concentration. Delftia antagonized Pseudomonas and members of Xanthomonadaceae. The relative abundance of most bacterial genes remained unchanged despite a five-fold increase in the metal concentration, but that of some EPS genes required for exopolysaccharide synthesis, and those related to the reduction of nitrite to nitrous oxide decreased which may alter the bioreactor functioning.

Influence of wild ungulates on the secondary succession of an Apennine silver fir forest after windthrow

Windstorms are natural factors in vegetation dynamics, but their intensity is increasing and undermines the forest resilience. Post-event interventions depend on forest types and management purposes. To promote mixed stands that are less susceptible to windthrow than monocultures, natural tree regeneration is usually recommended. However, wild ungulates attracted by the increased food supply in the new clearings can influence the secondary succession and slow down vegetation recovery. The impact of ungulate pressure on secondary successions in blowdown areas is still poorly known, especially in Mediterranean areas, which is particularly vulnerable to climate stressors. We investigated this topic using a monospecific silver fir (Abies alba) forest of artificial origin in the Apennines as a model system. The forest was left to natural succession after a severe windthrow in 2015, offering the opportunity to establish an ungulate exclosure experiment to analyse vegetation changes over six years. For the whole plant community, cover and height, α-diversity (species richness, Shannon and evenness indexes), and species composition were recorded yearly, together with tree seedling density, in open and fenced plots at increasing distances from the forest edge. Ecological and functional traits (proportion of light-demanding and forest specialists, endo-/epi-zoochorous species), and life-forms of the community samples were also analysed. Overall, we found that ungulates significantly influenced the dynamic trajectories of secondary succession. The effects on plant cover and diversity were negative and increased with distance from the forest edge. The presence of ungulates favoured generalist species and endozoochorous taxa. However, distance from the forest edge strongly reduced the latter effect. The average density of tree seedlings was overall high (ca. 10,000/ha), but it was strongly reduced by ungulates for three deciduous species and A. alba, the most browsed species. Natural recolonization after windthrow in Apennine pure silver fir stands may favour the formation of mixed, less susceptible forests, but the current ungulate pressure slows down this process, especially in the areas furthest from the forest edge.

Improved Straw Decomposition Products Promote Peanut Growth by Changing Soil Chemical Properties and Microbial Diversity

The ameliorative effects of straw decomposition products on soil acidification have been extensively studied. However, the impact of chemically treated straw decomposition products on crop productivity and the underlying microbial mechanisms remain unclear. This study aimed to investigate the effects of two dosages of Ca(OH)2-treated straw decomposition products of peanuts on red soil acidity, fertility, and bacterial and fungal diversity through a pot experiment. The pot experiment included four treatments: chemical nitrogen, phosphorus, and potassium (NPK) fertilization alone (CK), NPK chemical fertilization combined with peanut straw decomposition products (PS), NPK chemical fertilization combined with 4% Ca(OH)2-treated peanut straw decomposition products (PS4Ca), and NPK chemical fertilization combined with 8% Ca(OH)2-treated straw decomposition products (PS8Ca). High-throughput sequencing was performed to investigate the effects of these treatments on soil microbial diversity. The treatments with PS, PS4Ca, and PS8Ca significantly increased soil pH, exchangeable base cations, and nutrient content, whereas they decreased the exchangeable acid, especially exchangeable aluminum. The peanut growth improved substantially with the application of straw decomposition products. Specifically, PS4Ca significantly increased the Shannon and Richness indices of fungi. The principal coordinate analysis showed that the soil microbial communities in the straw decomposition product treatments were significantly different from CK. Linear discriminant analysis effect size identified unique bacteria and fungi between treatments. The Mantel test indicated that exchangeable base cations and pH were significantly positively correlated with bacterial communities, whereas available potassium was positively correlated with fungal communities. The partial least squares path modeling revealed that the bacterial communities positively and directly affected all peanut agronomic traits. In contrast, the fungal communities had a negative and direct effect only on peanut 100-pod weight. Therefore, adding Ca(OH)2-treated straw decomposition products could effectively improve crop productivity by alleviating soil acidification, increasing soil nutrients, and subsequently changing microorganisms.

KEANEKARAGAMAN JENIS KUPU-KUPU DI DESA BOMBA KECAMATAN LORE SELATAN KABUPATEN POSO

The Sintuwu Maroso KPH area, which is located in Bomba Village, South Lore District, has quite high biodiversity, one of which is butterflies. Butterflies are insects that belong to the order Lepidoptera. Butterflies play an important role in the ecosystem and maintain balance and enrich natural biodiversity. These insects are also important in agriculture, art, culture and human civilization. The Sintuwu Maroso KPH area, Bomba Village, South Lore District, Poso Regency, is a primary forest with maintained sustainability. Primary forest is a good place for butterfly habitat, so it is necessary to protect these butterflies. And research on these butterflies in the Sintuwu Maroso KPH area is still rare, as butterflies play an important role in plant pollination. Therefore, it is necessary to research the diversity of butterfly types. This research was carried out for 2 (two) months from October 2023 to November 2023, which took place in the KPH Sintuwu Maroso area, Bomba Village, South Lore District, Poso Regency, Central Sulawesi. Data collection and the number of individual types of butterflies used the Point Count method with eleven points. Data analysis used in the research is: species diversity index, species richness index, and species evenness index.

Tactics for Creating Tree Bank for Community Environment and Household Economy in Thailand

This article aimed to present strategies for creating a tree bank. Activities in tree bank plots for sustainable community environmental management and raising the household economy according to the new economic model were studied. The research area is a community that has successfully managed a tree bank and has been praised as a model in 3 regions, including 3 locations: Ban Tham Suea tree bank in Phetchaburi province, Khao Chakan agroforestry tree bank in Sa Kaeo province and Ban Khlong Ruea tree bank in Chumphon province. Data were collected through in-depth interviews. Group interviews were conducted and tree survey plots in the field were prepared. Committee members of the Tree Bank and representatives of the 3 Bank for Agriculture and Agricultural Cooperatives (BAAC), 11 people each, totaling 33 people were purposive sampling. Content analysis and the abundance of plant species were analyzed using the Menhinick (1964). The research results showed that the strategy for creating a tree bank involved group forming of household members with their own land by planting trees in agroforestry plots. The group acquire wood as an asset and use trees as collateral to guarantee loans from financial institutions that are guaranteed by the state. Environmental activities were organized by planting trees of at least 25 perennial trees per rai. 58 plant species as specified by the BAAC were chosen. Nourish the soil with compost made from scraps of leaves and branches. The richness index (R2) analysis showed that the abundance of tree species in all plots was at a high level (R2 =2.5-4.5). In terms of upgrading the household economy, knowledge of the production of firewood and burn charcoal, wood vinegar from trees, wood processing for house construction and furniture products was disseminated by the tree bank by organizing learning center and eco-tourism. Collaborative networks with organizations and educational institutions were built in order to use the tree bank for sustainable development.

Caesarean section and associated factors in Nigeria: assessing inequalities between rural and urban areas—insights from the Nigeria Demographic and Health Survey 2018

IntroductionWhen medically indicated, caesarean section (CS) can be a life-saving intervention for mothers and their newborns. This study assesses the prevalence of CS and its associated factors, focussing on inequalities between rural and urban areas in Nigeria.MethodsWe disaggregated the Nigeria Demographic and Health Survey 2018 and performed analyses separately for Nigeria’s overall, rural, and urban residences. We summarised data using frequency tabulations and identified factors associated with CS through multivariable logistic regression analysis.ResultsCS prevalence was 2.7% in Nigeria (overall), 5.2% in urban and 1.2% in rural areas. The North-West region had the lowest prevalence of 0.7%, 1.5% and 0.4% for the overall, urban and rural areas, respectively. Mothers with higher education demonstrated a greater CS prevalence of 14.0% overall, 15.3% in urban and 9.7% in rural residences. Frequent internet use increased CS prevalence nationally (14.3%) and in urban (15.1%) and rural (10.1%) residences. The southern regions showed higher CS prevalence, with the South-West leading overall (7.0%) and in rural areas (3.3%), and the South-South highest in urban areas (8.5%). Across all residences, rich wealth index, maternal age ≥ 35, lower birth order, and ≥ eight antenatal (ANC) contacts increased the odds of a CS. In rural Nigeria, husbands’ education, spouses’ joint healthcare decisions, birth size, and unplanned pregnancy increased CS odds. In urban Nigeria, multiple births, Christianity, frequent internet use, and ease of getting permission to visit healthcare facilities were associated with higher likelihood of CS.ConclusionCS utilisation remains low in Nigeria and varies across rural-urban, regional, and socioeconomic divides. Targeted interventions are imperative for uneducated and socioeconomically disadvantaged mothers across all regions, as well as for mothers in urban areas who adhere to Islam, traditional, or ‘other’ religions. Comprehensive intervention measures should prioritise educational opportunities and resources, especially for rural areas, awareness campaigns on the benefits of medically indicated CS, and engagement with community and religious leaders to promote acceptance using culturally and religiously sensitive approaches. Other practical strategies include promoting optimal ANC contacts, expanding internet access and digital literacy, especially for rural women (e.g., through community Wi-Fi programs), improving healthcare infrastructure and accessibility in regions with low CS prevalence, particularly in the North-West, and implementing socioeconomic empowerment programs, especially for women in rural areas.

DIVERSITY OF BATS IN HALABAN MONITORING POST AREA, SEI BETUNG, GUNUNG LEUSER NATIONAL PARK

Halaban Monitoring Post, Sei Betung Resort, Gunung Leuser National Park is a rehabilitated forest restoration location since 2017 after previously being diversified from oil palm land. The location has currently become a habitat for various types of animals, including bats. The identification of bat species at the Halaban Monitoring Post is conducted to assess the presence of fauna, with important ecological roles in pollination. Identification was conducted using mist nets installed at five observation points. Our observations showed that 87 individuals of Microchiroptera family bats were found, belonging to 4 species: Cynopterus brachyotis (38 individuals), Cynopterus minutus (15 individuals), Glischropus tylopus (1 individual), Hipposideros cervinus (33 individuals). Further analysis showed Shannon-Wiener diversity index ranges from 0.0 to 0.94 and Margalef species richness index ranges from 0.0 to 0.69. Bat abundance tends to be evenly distributed with an evenness index of 0.0 to 1.35. There is a dominant species at one of the locations with a dominance index value of 0.85.

Fire effects on plant communities in Ozark woodlands and glades

BackgroundDecades of fire suppression caused drastic changes to community structure and composition across ecosystems, including in Ozark woodlands in Missouri, USA. Reintroducing fire can restore ground flora by reducing midstory tree density, increasing ground layer light, and reducing leaf litter accumulation, but we lack a clear understanding of how these effects vary across time and space. We investigated the effects of repeated prescribed fire on ground flora species richness, floristic quality, abundance, community composition, and stand structure over 20 years in a landscape matrix of dry-mesic woodlands, dry woodlands, and glades using data collected from the Ozark National Scenic Riverways Fire Effects Monitoring program in the Current River Watershed in the Missouri Ozarks.ResultsWe found that fire plays a key role in driving community structure and dynamics across community types, although with varying levels of intensity. Herbaceous species richness, abundance, and floristic quality index increased across all community types, while mean coefficient of conservatism decreased. Abundance and floristic quality effects were stronger in drier sites. Community composition changed with successive burns, resulting in several indicator species for post burn treatments. The density of midstory trees declined across community types with repeated fire. The number of burns significantly affected overstory tree density overall, but overstory tree density only declined in dry woodlands and glades and not in dry-mesic woodlands.ConclusionsOur results suggest that landscape fire shapes plant community structure and dynamics. Specifically, these findings show that fire effects vary among community types and suggest that land managers should consider landscape heterogeneity in fire application for restoration. Separate community types imbedded in the same landscape may respond to fire differently. Understanding repeated fire effects over several decades across multiple community types is critical to informing fire-driven woodland restoration across landscape scales.

Spatial variation of skilled birth attendance and associated factors among reproductive age women in Ethiopia, 2019; a spatial and multilevel analysis.

The majority of maternal deaths were associated with a lack of access to skilled birth attendance. Because childbirth accounts for most maternal deaths, skilled birth attendance is crucial for reducing maternal mortality. The use of skilled birth attendance in Ethiopia is low, and it is crucial to identify factors that determine the use of skilled birth attendance. Hence, this study aimed to assess the spatial distribution, wealth-related inequality, and determinants for skilled birth attendance in Ethiopia. Secondary data analysis was done with a total weighted sample of 5,251 reproductive-aged women using the 2019 mini EDHS. The concentration index and graph were used to assess wealth-related inequalities. Spatial analysis was done to identify the spatial distribution and multilevel logistic regression analysis was used to identify predictors of skilled birth attendance in Ethiopia. Analysis was done using STATA version 14, ArcGIS, and SaTscan software. The prevalence of skilled birth attendance was 50.04% (95% CI: 48.69%, 51.40%) in Ethiopia. Old age, being married, being educated, having television and radio, having ANC visits, being multiparous, having large household sizes, having a rich wealth index, living in rural residence, and living in a high level of community poverty and women's education were significant predictors of skilled birth attendance. Skilled birth attendance was disproportionately concentrated in rich households [C = 0.482; 95% CI: 0.436, 0.528]. High prevalence of unskilled birth attendance was found in Somalia, SNNP, Afar, and southern parts of the Amhara regions. Primary clusters of unskilled birth attendance Somalia and some parts of Oromia region of Ethiopia. Half of the women in Ethiopia did not utilize skilled birth attendants with significant spatial clustering. Age, marital status, educational status, ANC Visit, having television and radio, parity, household size, wealth index, residence, community level poverty, and community level of women's education were significant predictors of skilled birth attendance. Skilled birth attendance was unevenly concentrated in rich households. The regions of Somalia, SNNP, Afar, and southern Amhara were identified as having a high prevalence of using unskilled birth attendance. Public health interventions should target those women at high risk of using unskilled birth attendants.

Species Composition and Diversity of Stored Grain Pests in Fortified Rice Collected from Different Districts of Telangana State, India

A study was conducted to measure the species composition and diversity of various stored grain insect pests in fortified rice collected from different districts of Telangana,India during 2023-2024. Theresults indicated that a total of six species of stored grain insects belonging to three orders viz., Coleoptera (3), Lepidoptera (2) and Psocoptera (1) were recorded in fortified rice. The six insect species were rice weevil, Sitophilus oryzae, Saw toothed beetle, Oryzaephilus surinamensis, redflour beetle, Tribolium castaneum, Angoumois grain moth, Sitotroga cerealella, rice moth, Corcyra cephalonica and pscocids. Among all these insects highest population of O. surinamensis was recorded in four districts of Telangana except in Ranga reddy and Nalgonda. The diversity indices indicated that Shannon-weiner diversity index (H) was high in Warangal district samples(H=1.426) while the Jagtial population recorded highest Margalef’s species richness index (R=1.27). The highest Pielou’s evenness index was reported from Nalgonda district (e=75), and Simpson diversity index of stored grain pests was found to be maximum (0.718) in Warangal district rice samples. The knowledge on species composition and diversity helps in planning timely management strategies for stored grain pests.

Identifying areas of conservation importance based on spatial patterns of evolutionary diversity for non-volant small mammals in the Andean Puna

Ecosystems around the world face a variety of threats from anthropogenic activities and drylands are among the most affected due to their unique environmental characteristics. To maintain phylogenetic history and ecological functionality in these areas, it is imperative to preserve community structure and composition by identifying and protecting key conservation areas. Various methods have been used to define these areas in need of protection; in this study, we used patterns of taxonomic and phylogenetic diversity in the arid lands of the Altiplano-Puna Bioregion of South America, using non-volant small mammal communities as a model system. Based on detailed records of species presence in the study area we estimated indices of species richness and phylogenetic redundancy. The geographic distribution of these indices was then compared to the distribution of protected areas in the region. These analyses identified areas around Lake Titicaca as being of exceptional conservation importance and in need of protection efforts. We propose a network of interconnected areas that together would provide high conservation value while allowing genetic exchange and facilitating ecological processes across landscapes.

ETIOPATHOGENETIC REASONING OF URETHRAL MICROBIOTA REHABILITATION IN PATIENTS WITH ACUTE INFECTIOUS URETHRITIS

The microbiota of the male genitourinary tract is a complex dynamic system that has not been sufficiently studied. Unlike the microbiome of the female urethral mucosa, which is constantly changing, the taxonomic composition and population level of the male urethral microbiome is more stable and independent of age. The aim of the study. To improve the results of treatment of patients with inflammatory processes of the urethra by determining the taxonomic composition, population level and microscopic indicators of the "macroorganism-microbiome" ecosystem of the microbiota of the urethra in men with acute urethritis.Material and methods. The taxonomic composition and population level of the first portion of urine of 69 sexually mature men (average age 34.8±7.14 years) with acute infectious (nonspecific) urethritis were investigated. Isolation of conditionally pathogenic bacteria was carried out by the bacteriological method using optimal nutrient media, their pH, temperature and cultivation time for each taxon. The identification of isolated pure cultures was carried out according to morphological, tinctorial, cultural, biochemical properties, as well as signs of pathogenicity and antigenic structure. To determine the mechanisms of colonization of the mucous membrane of the urethra by conditionally pathogenic microorganisms, the microecological method was used.Research results. According to the taxonomic composition and the level of microecological indicators of the "macroorganism-microbiome" ecosystem of the urethra microbiota (Margalef's species richness index, Whittaker's species diversity index, and Simpson's and Berger-Parker's species dominance indices), vulgar (common), hemolytic, and enteropathogenic Escherichia coli, coagulase-positive staphylococcus. The leading role in the formation of urethritis is played by ordinary enterobacteria - E. coli, a slightly smaller etiological role in the formation of urethritis in men belongs to S. aureus (less by 17.83%), E. coli Hly+ (less by 28.35%), enteropathogenic Escherichia coli (by 83.12%). Other microorganisms have a minimal etiological role. Conclusions. Acute urethritis in men is a polyetiological disease. Enterobacteria E. coli, E. coli Hly+, enteropathogenic Escherichia coli, K. pneumoniae, S. aureus, S. epidermidis, S. viridans are involved in the formation of the inflammatory process of the urethra. The leading causative agents of acute urethritis in men are E. coli, S. aureus, E. coli Hly+, enteropathogenic escherichia, which belong to uropathogenic escherichia.

The effect of the tidal cycle on the phytoplankton community assemblage in a mangrove-dominated tropical tidal creek.

A comparative assessment of phytoplankton dynamics during low tide (LT) and high tide (HT) was conducted from February 2022 to January 2023 in a tropical mesotidal creek, Manori, Mumbai, India. In total, 124 phytoplankton species were recorded. The HT resulted in greater species richness (124 species) and diversity indices (Shannon-Wiener's index) than the LT (102 species). The Pielou's evenness (J') and Simpson's dominance index (1-D) did not show significant fluctuations with the tides due to the marine phytoplankton species moving rhythmically in and out of the creek with the tides. Overall, the seasonal abundance was maximum during pre-monsoon at HT (5.79 × 103 u/L) and lowest in monsoon at LT (0.45 × 103 u/L), whereas spatial abundance was maximum at S1 (HT- 4.04 × 103 u/L) at HT and lowest at S3 (LT- 0.75 × 103 u/L) at LT. The diatoms dominated in their abundance (1.83 × 103 u/L and 3.82 × 103 u/L in HT) and diversity (77 in LT and 92 in HT). The species such as Coscinodiscus centralis, Coscinodiscus granii, Coscinodiscus radiatus, Triops furca, Melosira varians, Nitzchsia palea, Chaetoceros affinis, Skeletonema marinoi, Stephanocyclus meneghinianus, Planktoniella sol and Skeletonema costatumwere the dominant native residents in the creek. SIMPER analysis revealed that the maximum similarity was during the monsoon (47.65%), and the minimum was during the pre-monsoon (38.10%) at LT. However, in HT, the maximum similarity of phytoplankton shifted to post-monsoon (63.85%) and the minimum during the pre-monsoon (46.71%). The mean value of richness (d') and Shannon's diversity (H') showed a moderate phytoplankton diversity in the system. The environmental parameters (water temperature > pH > nitrate > salinity > DO > Alk > silicate) have a greater influence on the distribution of the phytoplankton community with tides as revealed by the Canonical correspondence analysis. Therefore, it has been found that tides play a significant role in the distribution and abundance of the phytoplankton community in a mesotidal creek environment.

Rhizosphere microbial community construction during the latitudinal spread of the invader Chromolaena odorata

The colonization of alien plants in new habitats is typically facilitated by microorganisms present in the soil environment. However, the diversity and structure of the archaeal, bacterial, and fungal communities in the latitudinal spread of alien plants remain unclear. In this study, the rhizosphere and bulk soil of Chromolaena odorata were collected from five latitudes in Pu’ er city, Yunnan Province, followed by amplicon sequencing of the soil archaeal, bacterial, and fungal communities. Alpha and beta diversity results revealed that the richness indices and the structures of the archaeal, bacterial, and fungal communities significantly differed along the latitudinal gradient. Additionally, significant differences were observed in the bacterial Shannon index, as well as in the structures of the bacterial and fungal communities between the rhizosphere and bulk soils. Due to the small spatial scale, trends of latitudinal variation in the archaeal, bacterial, and fungal communities were not pronounced. Total potassium, total phosphorus, available nitrogen, available potassium and total nitrogen were the important driving factors affecting the soil microbial community structure. Compared with those in bulk soil, co-occurrence networks in rhizosphere microbial networks presented lower complexity but greater modularity and positive connections. Among the main functional fungi, arbuscular mycorrhizae and soil saprotrophs were more abundant in the bulk soil. The significant differences in the soil microbes between rhizosphere and bulk soils further underscore the impact of C. odorata invasion on soil environments. The significant differences in the soil microbiota along latitudinal gradients, along with specific driving factors, demonstrate distinct nutrient preferences among archaea, bacteria, and fungi and indicate complex microbial responses to soil nutrient elements following the invasion of C. odorata.

Initial Alterations of Fish Community Structure and Diversity Following Fishing Cessation in Qilu Lake, China.

The Qilu Lake is an eutrophic shallow lake located in Yunnan Province, China. An ecological fishery project was initiated in the lake from 2011 to 2021 to introduce filter-feeding fish species that feed on algae, with the aim of improving water quality. In January 2022, when the ecological fishery project expired, all fisheries-related activities (including fish stocking and fishing activities) ceased in the lake. To comprehensively evaluate the initial alterations in fish community structure and diversity resulting from the fishing cessation in the Qilu Lake, the present study conducted field surveys within the one year before the fishing cessation (referred to as BFC) and the one year after the fishing cessation (referred to as AFC). A total of twenty-one fish species were collected, including four native species. Four species were recorded in the lake for the first time, including Pelteobagrus fulvidraco, Pelteobagrus vachelli, Paramisgurnus dabryanus, and Hyporhamphus intermedius. The number of fish species decreased from 21 to 13 following the fishing cessation. The fishes collected in both BFC and AFC are mainly omnivorous-feeding and of bottom-dwelling habits. The mean size of the fishes in the AFC sample shows a significant decrease compared to those in BFC. After the fishing cessation, the Shannon-Wiener diversity index and Margalef richness index of the fish slightly declined. The fish community structure of the Qilu Lake exhibits a high degree of similarity to adjacent lakes in central Yunnan. Our study demonstrates a significant shift in the fish community of the Qilu Lake following the fishing cessation, one which may adversely impact the stability of the lake ecosystem. To enhance fish species diversity in the Qilu Lake, it is recommended that policies be implemented to promote the ecological fishery project and improve habitat restoration for native fish species, while also regulating fish community structure.

Effects of polypeptidin feeding on growth and intestinal flora of Apostichopus japonicus

Apostichopus japonicus (A. japonicus) is known as one of the most popular varieties in aquaculture due to its rich nourishment and potential medicinal value. In recent years, with the abnormal change of marine environment and global climate, new challenges are arising continually in the culture process of A. japonicus. Intestinal flora plays an important role in host health and growth, and a lot of studies confirmed the close relationship between the composition change of intestinal flora and the growth of sea cucumbers. In this study, polypeptidin belonging to bacteriocins, was as an additive ingredient in sea cucumber feed. The growth of A. japonicus increased significantly after polypeptidin feeding, and the growth rate reached the highest with 1 % polypeptidin especially. Subsequently 16 S rRNA of gut microbiota from 1 % polypeptidin group was sequenced and analyzed for richness and diversity index, but the results showed that polypeptidin supplement did not markedly change the diversity and main composition of gut microbiota compared to the control. So the further analyze was performed by dependent t-test for paired samples, and found that the abundance of only a few of species at the class level changed significantly, including Alphaproteobacteria, Desulfotomaculia and Chlamydiae, but many species at the genus level changed significantly. Some important metabolic pathways were identified through function prediction, like TCA cycle, streptomycin biosynthesis and phenylalanine metabolism. At this basis, the analysis combined with the genuses and the metabolic pathways demonstrated that polypeptidin might regulate the richness of some bacteria, which could be involved in enzyme degradation, antibacterial substances secreting or underlying pathogenic tendency of gut microbiota ecosystem. These fine-tunings instead of main community structure change were probably more beneficial to the intestinal flora health, and finally contributed to the growth of A. japonicus. Thus, polypeptidin serves as a mild, non-stimulating feed supplement for A. japonicus, and has good prospects for application.

Microplastics predominantly affect gut microbiota by altering community structure rather than richness and diversity: A meta-analysis of aquatic animals

The impacts of microplastics on the gut microbiota, a crucial component of the health of aquatic animals, remain inadequately understood. This phylogenetically controlled meta-analysis aims to identify general patterns of microplastic effects on the alpha diversity (richness and Shannon index), beta diversity, and community structure of gut microbiota in aquatic animals. Data from 63 peer-reviewed articles on the Web of Science were synthesized, encompassing 424 observations across 31 aquatic species. The analysis showed that microplastics significantly altered the community structure of gut microbiota, with between-group distances being 87.75% higher than within-group distances. This effect was significant even at environmentally relevant concentrations (≤1 mg L−1). However, their effects on richness, Shannon index, and beta diversity (community variation) were found to be insignificant. The study also indicated that the effects of microplastics were primarily dependent on their concentration and size, while the phylogeny of tested species explained limited heterogeneity. Furthermore, variations in gut microbiota alpha diversity, beta diversity, and community structure were correlated with changes in antioxidant enzyme activities from the liver and hepatopancreas. This implies that gut microbiota attributes of aquatic animals may provide insights into host antioxidant levels. In summary, this study illuminates the impacts of microplastics on the gut microbiota of aquatic animals and examines the implications of these effects for host health. It emphasizes that microplastics mainly alter the community structure of gut microbiota rather than significantly affecting richness and diversity.