Dominant Species Research Articles

Spatial patterns of hydroecological health in the semi-arid yellow river basin: Revelations from machine learning models

The ecosystem of semi-arid watersheds is influenced by a combination of natural climate factors, rainfall, and habitat destruction, resulting in complex mechanisms of spatial differentiation and evolution of water ecological health. Indicator selection in mainstream water ecological health assessment methods, such as the Index of Biotic Integrity (IBI), often relies on subjective reference point choices. This approach tends to overlook the comprehensive impacts and interactions among various environmental stressors. For watersheds significantly influenced by natural climatic factors, considerable uncertainties arise, leading to a lack of scientific justification for establishing water ecological health protection goals. In this study, the nonlinear capabilities of the random forest (RF) model were applied to reduce subjectivity in traditional water ecological health assessments and to more accurately reveal the emerging spatial differentiation patterns and underlying causes of water ecological health in the Wei River Basin (WRB), the largest typical semi-arid watershed of the Yellow River in China. Our findings indicate: (1) Traditional evaluation indices indicate that the overall water ecological health of the WRB is classified as sub-healthy (60 %). The core indicators include dominant species, total algal density, and the percentage of diatom density, with no significant spatial differentiation observed. (2) An improved water ecological health assessment method for semi-arid watersheds, based on the RF model, has been developed to replace traditional subjective judgment steps. This method establishes a complex multi-input–output response relationship (R2 > 0.85) between environmental stress indicators and the biological integrity index for the WRB. (3) The model results identify key driving factors affecting changes in water ecological health in semi-arid watersheds, with the sensitivity of the new model increasing nearly 11-fold compared to traditional IBI methods. (4) Following improvements, the water ecological health characteristics of the WRB exhibit significant spatial heterogeneity, with a higher dispersion coefficient (1.21), and demonstrate enhanced nonlinear response trends to climatic factors. The application of machine learning models indicates that traditional methods may underestimate the extent of ecological health degradation in watersheds and tend to oversimplify spatial heterogeneity characteristics.

Bacterial synergy and relay for thermophilic hydrogen production through dark fermentation using food waste

BackgroundFood waste is a significant global issue, with 1.3 billion tons generated annually, a figure expected to rise to 2.1 billion tons by 2030. Conventional disposal methods, such as landfilling and incineration, present environmental challenges, including methane emissions and pollution. Hydrogen production through dark fermentation presents a sustainable alternative, offering both waste management and renewable energy generation. This study investigates the bacterial synergy and relay mechanisms involved in thermophilic H2 production using food waste as a substrate. PurposeThe primary aim of this research was to analyze the metabolic pathways and dynamics of functional genes prediction during thermophilic H2 production from food waste, focusing on the role of bacterial consortia in enhancing H2 yields. MethodsA continuous stirred-tank reactor (CSTR) was operated using food waste as the substrate and a thermophilic bacterial consortium as the inoculum. The study utilized genomic analysis to monitor changes in bacteriobiome composition over time and to correlate these changes with H2 production. Volatile fatty acids (VFAs) and H2 production rates were analyzed using gas chromatography and high-performance liquid chromatography (HPLC). The Kyoto Encyclopedia of Genes and Genomes (KEGG) database was employed to identify functional genes involved in the fermentation process. ResultsThe study identified key bacterial species, including Caproiciproducens and Caproicibacter, that dominated during the later stages of H2 production, replacing earlier dominant species such as Clostridium. These shifts in bacterial dominance were strongly correlated with sustained H2 production rates ranging from 353 to 403 mL·L−1·h−1, with H2 concentrations between 55 % and 62 % (v/v). Functional gene analysis revealed significant pathways related to polysaccharide degradation, glycolysis, and dark fermentation. ConclusionsThis study highlights the importance of bacterial synergy and relay in maintaining continuous H2 production from food waste under thermophilic conditions. The findings provide insights into optimizing biohydrogen production processes, emphasizing the role of specific bacterial species in enhancing efficiency. These results contribute to the development of sustainable waste management strategies and renewable energy production.

Evaluation of Genotoxic and Hemolytic Effects of Aphanizomenon flos-aquae and Microcystis aeruginosa Biomass Extracts on Human Blood Cells In Vitro

This study explores the in vitro effects of cyanotoxins from the methanolic extract of the cyanobacteria Aphanizomenon flos-aquae and Microcystis aeruginosa on human blood cells, with samples drawn from the Gruža reservoir in Serbia. These cyanobacteria, which made up 98.5% of the reservoir’s phytoplankton, reached densities of 4,656,450 cells mL−1, with A. flos aquae (3,105,120 cells mL−1) as the dominant species, followed by M. aeruginosa (1,480,130 cells mL−1). A cyanotoxin analysis of biomass detected anatoxin-a (3.56 µg g−1), cylindrospermopsin (6.86 µg g−1), microcystin LR (0.87 µg g−1), and microcystin RR (2.47 µg g−1). This study assessed the genotoxic potential of the methanolic extract of the cyanobacterial biomass by evaluating the DNA damage and the Genetic Damage Index (GDI) in peripheral blood lymphocytes (PBLs) from healthy donors. The results showed a dose-dependent increase in the DNA damage, from 35.67 ± 4.93% at 10 µg mL−1 to 95.67 ± 1.53% at 100 µg mL−1, with a corresponding rise in the GDI from 0.61 ± 0.02 to 2.39 ± 0.07. The extract also caused the concentration-dependent hemolysis of red blood cells, with 5.63% hemolysis at the highest concentration (200 µg mL−1). These findings underscore the significant genotoxic risks posed by cyanotoxins from biomass extracts of A. flos aquae and M. aeruginosa, particularly in water sources used for human consumption.

Acute Toxicity of Mycotoxigenic Fungi Isolates in Ready-to-Eat Meat in Buea, Cameroon

Introduction: Meat is an important source of nutrition for many people worldwide. Away from homes, it is widely consumed in restaurants (e.g. small roadside) and non-restaurants (including drinking parlors and open-air)in various forms assnack. Objective: This paper reports on the acute toxicity of mycotoxigenic fungi isolates from various ready-to-eat meat from Buea, Cameroon. Method: Ten varieties of ready-to-eat meat samples (N=130: raw beef (n=18), beef soya (n=29), fried chicken (n=11), chicken soya (n=10), snail soya (n=13), fried pork (n=06), fried cow liver (n=13), roasted goat (n=06), boiled cow skin (n=07) and smoked beef (n=17).were collected from Buea municipality. The samples were cultures, and fungal isolates isolated microscopically. Thereafter, an acute toxicity test using 24 young BALB/c mice (weight range: 22-25g) was performed. Results: A total of 40 mycotoxigenic fungi belonging to five genera (Aspergillus, Penicillium, Fusarium, Rhizomucor, and Rhizopus) were identified. The most dominant species was Aspergillus (unidentified Aspergillus species, 23.1%; and Aspergillus ochraceus,10.3%).The order of Aspergillus fungi proliferation were roasted goat liver(20%), fried chicken (20%), snails soya (20%)ean body weight of test mice significantly decreased (p<0.05) after the first 7 days of feeding with a mycotoxigenic fungi-supplemented diet relative to control mice that ate healthy diets. Aspartate Transaminase (AST, range: 169.9-563.1U/L) and Alanine Transaminase (ALT, range:521.1-707.5U/L) levels were significantly (p<0.05) higher than the reference values for healthy mice (range: 60-100U/L for AST and 25-6U/L for ALT). Conclusion: Given the toxicity potentials of mycotoxigenic fungi, e.g. production of toxic secondary metabolites, not reported in this paper, and demonstrated by the liver toxicity/function test, ready-to-eat meat in Buea, Cameroon may not be adequately safe for consumption.

Population dynamics of defective viral genomes of tomato black ring virus during host-to-host transmission.

Defective viral genomes (DVGs) have been identified in vivo and in vitro for different virus species infecting humans, animals, and plants. The ability to form DVGs during the passaging of virus in one host has been demonstrated, i.e., for tomato black ring virus (TBRV). In our research, RNA-Seq data obtained after TBRV passaging through a combination of four distinct host species were analyzed. Our results indicate that the level of DVG abundance varied across host plant combinations. Deletions were the most prevalent class of DVGs, with the domination of longer species. Additionally, the conserved junction sites in the TBRV genome were identified, resulting in the generation of identical deletions in independently evolved viral lineages. In summary, our findings provide significant insights into the origin and structure of DVGs of plant viruses. The obtained results will help in understanding viral evolution and host-virus interactions.

Facet-induced fractionation of humic acid by hematite and the promoted-photodegradation of 17β-estradiol catalyzed by hematite-humic complex

Hematite is a ubiquitous mineral with different dominant facets in the environment, which could adsorb humic acids (HA) to form photoactive hematite-HA complex. In this study, we prepared hematite nanocubes (HNC), hematite nanoplates (HNP) and hematite nanorhombs (HNR) with dominant facets as {012}, {001} and {104}, respectively. The abilities of the three hematites to adsorb and fractionate HA were compared. Our results indicated that the components with low molecular weight, high aromaticity and more oxygenated functional groups of HA were preferentially adsorbed. The fractionation degree followed the order of HNP > HNR > HNC, attributing to the coordination ability of different hematites. After hematite formed complexes with HA, it could promote the photodegradation of 17β-estradiol under visible light. The photoactivities of the three hematite-HA complexes were also compared. Since HNP adsorbed the most photochemically active HA components, HNP-HA showed the strongest enhancement for the degradation of 17β-estradiol. During the photodegradation process, the excited triplet state of HA (3HA*) and superoxide radical (O2•−) were identified as the dominant reactive species. Our results provide new insights into the role of hematite facets towards adsorption and fractionation of HA and photodegradation of co-existing contaminants, which would improve the understanding of the fate of pollutants in the presence of hematite and HA.

Diversity of Soil Macro Arthropods in the Arable Land of Cotton Zone, North Cameroon

Arthropods constitute the most diverse and dominant species of biodiversity in terrestrial ecosystems. Despite this great abundance, our understanding of their ecological organization and diversity remains unknown in certain habitats. The present study aimed to evaluate the diversity of soil macro-arthropods in the arable land of six localities in the arable land of cotton zone of Cameroon. For this purpose, collections of soil macro-arthropods were carried out using Barber traps and subpots for two consecutive years 2018-2019. During the entire duration of the study, nearly 33.423 soil macro-arthropods were collected belonging to 67 species divided into 11 orders and 27 families. After classification, the most abundant insect groups were Coleoptera (36.9%), Hymenoptera (33.5%), and Orthoptera (22.9%), while the groups of Neuroptera, Hemiptera and Isoptera practically a low level of relative abundance. The proportions of the different families of soil macro-arthropods sampled varies from one locality to another and three large families were in the majority: Formicidae (32.4%), Acrididae (19.5%) and Tenobrionidae (15.7%). Soil macro-arthropod samples collected in Kodek, Sanguere Njoï and Gashiga, respectively recorded the highest species richness as well as the Shanon-Weaver Diversity and Evenness index. In all the arable soils of the localities studied, the soil arthropods tend to have an Equidistribution of individuals and Equitability varies from 0.5 to 0.8. The soil macro-arthropods collected in the arable land of the cotton zone of North Cameroon were mainly phytophagous and saprophagous with a strong beneficial potential in these different ecosystems.

Southeastern Ohio Hemlock Stands Prior to Hemlock Woolly Adelgid Infestation: Baseline Conditions from 2 Surveys a Decade Apart

The Hocking Hills of southeastern Ohio are situated at the western range boundary of eastern hemlock, where this foundation species occurs in isolated pockets in ravines and on steep slopes. The goal of this study is to characterize these hemlock stands prior to infestation by hemlock woolly adelgid (HWA), which recently entered the state and is likely to cause high mortality if untreated. Individuals in 30 plots established from 2008 to 2011 were resurveyed in 2020, allowing determination of growth rates and mortality rates. Each plot was paired with an upslope transect in the resurvey to record non-hemlock species likely to seed in from above. Tree species diversity in the plots is low (Shannon H’ < 1), as eastern hemlock remained the dominant species in all plots; storm damage and competitive thinning appeared to account for most mortality across all species. Hemlock growth rates were comparable to deciduous species. Common co-occurring species are statistically associated with particular topographic and soil properties on the plots. Following future hemlock mortality, tulip-poplar, chestnut oak, white oak, sweet birch, and red maple may be among the first species to dominate the canopy; Japanese stiltgrass currently appears to be the invasive species of greatest concern. An understanding of pre-HWA composition, structure, and forest dynamics can inform restoration efforts, if in the future long-term, sustainable HWA control or host-tree resistance is developed; this understanding can also apprise management and conservation efforts in the unique hemlock stands of southeast Ohio.

Southeastern Ohio Hemlock Stands Prior to Hemlock Woolly Adelgid Infestation: Baseline Conditions from 2 Surveys a Decade Apart

The Hocking Hills of southeastern Ohio are situated at the western range boundary of eastern hemlock, where this foundation species occurs in isolated pockets in ravines and on steep slopes. The goal of this study is to characterize these hemlock stands prior to infestation by hemlock woolly adelgid (HWA), which recently entered the state and is likely to cause high mortality if untreated. Individuals in 30 plots established from 2008 to 2011 were resurveyed in 2020, allowing determination of growth rates and mortality rates. Each plot was paired with an upslope transect in the resurvey to record non-hemlock species likely to seed in from above. Tree species diversity in the plots is low (Shannon H’ < 1), as eastern hemlock remained the dominant species in all plots; storm damage and competitive thinning appeared to account for most mortality across all species. Hemlock growth rates were comparable to deciduous species. Common co-occurring species are statistically associated with particular topographic and soil properties on the plots. Following future hemlock mortality, tulip-poplar, chestnut oak, white oak, sweet birch, and red maple may be among the first species to dominate the canopy; Japanese stiltgrass currently appears to be the invasive species of greatest concern. An understanding of pre-HWA composition, structure, and forest dynamics can inform restoration efforts, if in the future long-term, sustainable HWA control or host-tree resistance is developed; this understanding can also apprise management and conservation efforts in the unique hemlock stands of southeast Ohio.

Determination of Total Flavonoid Content from Extract and Fractions of Mangrove Leaves (Rhizopora mucronata)

Indonesia is an archipelagic country with a very wide coastal area. Lombok Island has a coastal area with quite extensive mangrove forest areas. Rhizopora mucronata was the most dominant species found in the region. The Rhizopora mucronata species was a plant from the Rhizoporaceae family reported to have antibacterial, antifungal, and antioxidant activity. These biological activities were caused by the presence of secondary metabolite compounds in R. mucronata, one of which is flavonoids. Research regarding the flavonoid content of R. mucronata leaves has not been explored. Therefore, the study aimed to determine the total flavonoid content in extracts and fractions of R. mucronata leaves using the spectrophotometric UV-Vis method. R. mucronata mangrove leaves simplicia were extracted using the sonication method using 96% ethanol solvent, then fractionated using the liquid-liquid extraction method with n-hexane, ethyl acetate, and water. The percentage yield of 96% ethanol extract, water fraction, ethyl acetate fraction, and n-hexane fraction respectively were 42.33%; 43.147%; 40.49%; 9.74%; and 32.49%. The TLC test showed the presence of flavonoid compounds detected in the extract and fractions which were marked with blue spots. The total flavonoid contents in the 96% ethanol extract, water fraction, ethyl acetate fraction, and n-hexane fraction were respectively (12,980; 14,160; 23,880; and 25,350) mg Quercetin equivalent/gram sample (mg QE/ g). The total flavonoid content of the extract and fractions of R. mucronata leaves were analyzed using the One-way ANOVA test method. The total flavonoid content in the n-hexane fraction and ethyl acetate fraction was significantly higher than the 96% ethanol extract and water fraction. The total flavonoid content of R. mucronata leaves was relatively high, which contributes to several of its biological activities.

Benthic foraminifera as bio-indicators of natural and anthropogenic conditions in Roscoff Aber Bay (Brittany, France).

Living benthic foraminifera, known as environmental bio-indicators of both natural and anthropogenic conditions in marine environments, were investigated in the coastal environment of Roscoff Aber Bay (Brittany, France). Eight sampling sites subject to natural variations (freshwater inputs, tides) and/or anthropogenic impacts (pollution, eutrophication) were studied over four seasons in 2021-2022 (November, February, May, August). We sought to understand the spatial distribution of foraminiferal populations within and between sampling sites over the different seasons and to identify sensitive species and those tolerant to anthropogenic impacts. To this end, sedimentary and biogeochemical characteristics of the sediments were examined by measuring grain size, temperature, oxygen, salinity, pH, environmental pigment concentration (chl a and phaeopigments), total organic carbon (TOC), isotopic ratios of carbon (δ13C), nitrogen (δ15N) and sulfide (δ34S), and chl a fluorescence. Considering these parameters as potential driving factors, four environments were distinguished among the sampling sites: open water, terrestrial, oligotrophic and eutrophic. These showed an increasing gradient of organic supply as well as very different microbial activities, highlighted by carbon and sulfide isotopic ratios. Foraminiferal population study revealed the dominant species characterising these main environments. The lowest abundance but highest diversity of foraminifera was found in the harbour site, associated with the dominance of Haynesina germanica, suggesting this species is tolerant to eutrophic environments and anthropogenic impacts. Open water was dominated by Ammonia beccarii and Elphidium crispum, while Quinqueloculina seminula was the most abundant species in the site with the greatest terrestrial influence. Interestingly, the observed organic enrichment of the harbour due to anthropogenic activities (fisheries, waste deposits, etc.) does not seem to significantly affect foraminiferal diversity. Overall, the benthic foraminiferal species in Roscoff Aber Bay appear to be an excellent proxy for marine environmental conditions under various natural and anthropogenic influences.

Synergistic effects of microplastics and sulfonamide on greenhouse gas emissions in agricultural ditch sediments: Insights into microbial interactions

Recently, concerns have been raised regarding concurrent pollution by microplastics and antibiotics in agricultural aquatic ecosystems. However, knowledge gaps remain regarding their combined effects on greenhouse gas (GHG) emissions and bacterial community assembly mechanisms. To address this, a microcosm experiment was performed to investigate the GHG (CH4, CO2, and N2O) emission characteristics and bacterial community assembly mechanisms in agricultural ditch sediments under co-exposure to different microplastics (polythene (PE), polylactic acid (PLA)), and sulfanilamide (SA). The global warming potential (GWP) of the different treatments was ranked as follows: SA+PLA (162.96 mg/m2/h) > PLA (123.49 mg/m2/h) > SA (121.75 mg/m2/h) > SA+PE (102.33 mg/m2/h) > CK (without microplastics or antibiotics, 84.67 mg/m2/h) > PE (78.29 mg/m2/h). Additionally, a phylogenetic bin-based null model and molecular ecological network analysis indicated that SA-induced selective pressures reduced compositional turnover, whereas microplastics enhanced drift effects and decreased network robustness. The co-contamination of SA with different microplastics exhibited the opposite effect on the network and assembly process, suggesting that disturbance-mediated species dominance alters the colonization of rare species. Collectively, these findings provide valuable evidence that the synergistic effects of biodegradable microplastic and SA can promote GHG emissions and influence the mechanisms underlying community assembly processes.

Soil Seed Banks Dynamics and Restoration Potential of Some Selected Forest Reserves in Southwest, Nigeria

This research investigated the regeneration potential of soil seed-bank along three soil depths in three secondary forest communities within Southwest Nigeria, for a better understanding of the potentials of the soil seed banks in facilitating succession towards a more natural forest of native tree species in International Institute of Tropical Agriculture (IITA) Forest Ibadan, Elephant Forest reserve Omo and Emerald Forest in Ikoyi Nigeria. Eight temporary plots of 20m by 40m using systematic line transect were laid in each forest. Soil samples were taken at three depths of 0–5 cm, 5–10 cm and 10–15cm and the seed bank composition was determined under a greenhouse condition. The results show that IITA forest has an abundance of 93 species with the highest in soil depth of 5-10 (35) and least exists at 10-15cm (24). The species evenness ranged from 0.92 to 0.96, with an average value of 0.94. Emerald forest had a total of 74 tree species with 0-5 cm depth having the highest species abundance (34), while depth of 5-10 cm (21) exhibit the least species abundance. At the forest, results of Species diversity indices show that at 0-5 cm depth 2.47 index value was recorded, a value much higher than what was recorded at 5-10 cm (2.40) and 10-15cm (2.36) respectively. The result of Elephant Forest reserve shows that a total of 87 tree species were recorded with 0-5 cm depth having the highest species abundance (40) followed by 5-10 cm (27), 10-15 (26) respectively. The Shannon Wiener index for Elephant Forest shows that 2.28 were recorded at 0-5 cm depth, 1.40 at 5-10 cm depth, and 1.70 at 10-15cm depth respectively. The soil seed bank could help in determining the status of regeneration potential of the three forests investigated. However, high dominance of tree species in the soil seed banks implies that the forest is disturbed and there is likelihood of tree species succeeding and dominating the forest ecosystem.

Patterns of benthic diversity in marine underwater caves of the Marseille Region (France, North-Western Mediterranean Sea)

Underwater caves are remarkable habitats of the Mediterranean Sea. In the present study, we compare the geomorphology of four underwater caves of the Marseille area and the associated sessile assemblages across two contrasted communities (Semi- Dark and Dark-cave communities). Using a non-destructive method of sampling, photoquadrats of the walls of the caves were performed in 2020 to assess the biodiversity and the structure of these communities. In addition, taking advantage of available reference data from 2015, we evaluate the changes in sponge assemblages for the period 2015-2020, focusing on observations of the Semi-Dark cave community. Our results illustrate how the diversity of environmental settings and cave morphologies shape the benthic community composition of the four caves. In all four caves, the Semi-Dark community is the more diverse and harbours the higher number of species when compared to the Dark community. Each cave presents a different species assemblage with in most cases, distinct dominant species which highlight the singularity of each cave. Moreover, our temporal change assessment demonstrates a critical decrease in sponge species richness for all caves, possibly related to the increasing frequency of marine heatwaves that have occurred in the last decade. Although some species (mostly in the Keratosa subclass) seem to be particularly affected, other species such as Chondrosia reniformis appear to have benefitted from the situation. Our findings underline the importance of biodiversity monitoring in a context of a rapidly changing environment, in particular in poorly resilient marine ecosystems such as underwater caves.

Both Biotic and Abiotic Factors Shape the Spatial Distribution of Aboveground Biomass in a Tropical Karst Seasonal Rainforest in South China

Forest biomass accumulation is fundamental to ecosystem stability, material cycling, and energy flow, and pit lays a crucial role in the carbon cycle. Understanding the factors influencing aboveground biomass (AGB) is essential for exploring ecosystem functioning mechanisms, restoring degraded forests, and estimating carbon balance in forest communities. Tropical karst seasonal rainforests are species-rich and heterogeneous, yet the impact mechanisms of biotic and abiotic factors on AGB remain incompletely understood. Based on the survey data of a 15 ha monitoring plot in a karst seasonal rainforest in Southern China, this study explores the distribution characteristics of AGB and its intrinsic correlation with different influencing factors. The results show that the average AGB of the plot is 125.7 Mg/ha, with notable variations among habitats, peaking in hillside habitats. Trees with medium and large diameters at breast height (DBH ≥ 10 cm) account for 83.94% of the aboveground biomass (AGB) and are its primary contributors; dominant tree species exhibit higher AGB values. Both biotic and abiotic elements substantially influence AGB, with biotic factors exhibiting the largest influence. Among abiotic factors, topographic factors have a strong direct or indirect influence on AGB, while soil physicochemical properties have the smallest indirect impact. This research provides a comprehensive understanding of AGB distribution and its influencing factors in tropical karst forests (KFs), contributing to the management of carbon sinks in these ecosystems.

Enhancing Organic Pollutant Degradation Efficiency through a Photocatalysis-Electro-Fenton System via MoS2 Crystal Morphology Regulation.

A photocatalysis-electro-Fenton (PEF) system was constructed via molybdenum disulfide (MoS2) to remove tetracycline (TC) without an external oxidant supply and solution pH adjustment. In the system, original graphite felt (GF) was used as a cathode, from which H2O2 was in situ generated continuously under power. MoS2 was motivated by visible light to facilitate the cycle of Fe2+/Fe3+, enhancing the Fenton process to produce •OH. The experimental results showed that the system can increase the degradation rate of pollutants by more than 5 times. Moreover, the quenching and electron paramagnetic resonance (EPR) tests demonstrated that •OH was the dominant active species. X-ray photoelectron spectroscopy (XPS) characterization, Mo concentration, and cycle experiments proved the excellent catalytic activity and chemical stability of MoS2. It is worth mentioning that the photocatalytic performances of different morphologies of MoS2 (flower, flake, and radar) were compared. As a result, flower-like MoS2 exhibited a much superior photoresponse than flake and radar, which could accelerate the Fe2+/Fe3+ cycle further effectively. These findings highlight the morphology-performance relationship of MoS2 under a PEF system and the mechanisms of contaminant degradation, which is of great significance for developing photoelectric Fenton technology.

High atmospheric dissolved organic nitrogen deposition in southeast Tibet

Nitrogen deposition has been highlighted in the last decades because it was considered as one control factor of global change. The Yarlung Tsangpo Grand Canyon acts as a major passage of monsoonal moisture transport from the Bay of Bengal into the Tibetan Plateau. However, the characteristics of nitrogen(N) deposition in this area are still unclear. Here, we established five N deposition monitoring sites and quantification the bulk N deposition fluxes from 2200 to 4600m above sea level in southeast Tibet. Results showed that the average precipitation amount of the five sites was 1127.7 mm. The dissolved organic nitrogen (DON) was the dominant species, and the deposition flux was 16.80 kg N ha−1 yr−1. The averaged NH4+-N deposition flux was 4.92 kg N ha−1 yr−1, whereas the NO3−-N deposition flux was 1.49 kg N ha−1 yr−1. In addition, the deposition fluxes of TDN, DON and NH4+-N were all significantly positive to precipitation amounts at all five sampling sites. However, the deposition flux of NO3−-N was significantly correlated with precipitation amount in the remote environment, and there was no correlation between precipitation amounts and NO3−-N deposition fluxes in human concentrated areas. TDN, DON and NH4+-N deposition were all concentrated in the plant growing season at all five sampling sites. In conclusion, the atmospheric TDN deposition flux in the Yarlung Zangbo Grand Canyon in southeast Tibet is mainly controlled by precipitation, and DON was the dominant species, followed by NH4+-N, and NO3−-N contribution was limited.

Diversity and Population of Ducks and Geese in Keibul Lamjao National Park (KLNP) in Manipur, India

As a part of the Asian Waterbird Census (AWC), surveys on ducks and geese were made at five (5) major waterbird congregation sites of Keibul Lamjao National Park (KLNP) during 2020-2024. A total of 18 species of ducks and two species of geese belonging to the family of Anatidae were recorded during the period. The duck species includes 14 migratory and 4 resident species and the two migratory geese species. Lesser Whistling Duck Dendrocygna javanica was the most abundant and dominant species in terms of population followed by Gadwall Anas strepera and Red - crested Pochard Netta rufina and minimum value was observed in Greylag Goose Anser anser. The Critically Endangered Baer’s Pochard Aythya fuligula was recorded in the year 2023 at Pabot Chingmang site (2 individuals). Another two globally Near threatened (NT) Ferruginous Pochard Aythya nyroca and Falcated Duck Anas falcata have been recorded here.

Comparative study of lysine acetylation in Vesicomyidae clam Archivesica marissinica and the manila clam Ruditapes philippinarum: adaptation mechanisms in cold seep environments

BackgroundThe deep-sea cold seep zone is characterized by high pressure, low temperature, darkness, and oligotrophy. Vesicomyidae clams are the dominant species within this environment, often forming symbiotic relationships with chemosynthetic microbes. Understanding the mechanisms by which Vesicomyidae clams adapt to the cold seep environment is significant. Acetylation modification of lysine is known to play a crucial role in various metabolic processes. Consequently, investigating the role of lysine acetylation in the adaptation of Vesicomyidae clams to deep-sea environments is worthwhile. So, a comparative study of lysine acetylation in cold seep clam Archivesica marissinica and shallow water shellfish Ruditapes philippinarum was conducted.ResultsA total of 539 acetylated proteins were identified with 1634 acetylation sites. Conservative motif enrichment analysis revealed that the motifs -KacR-, -KacT-, and -KacF- were the most conserved. Subsequent gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were conducted on significantly differentially expressed acetylated proteins. The GO enrichment analysis indicated that acetylated proteins are crucial in various biological processes, including cellular response to stimulation, and other cellular processes ( p < 0.05 and false discovery rate (FDR) < 0.25). The results of KEGG enrichment analysis indicated that acetylated proteins are involved in various cellular processes, including tight junction, motor proteins, gap junction, phagosome, cGMP-PKG signaling pathways, endocytosis, glycolysis/gluconeogenesis, among others (p < 0.05 and FDR < 0.25). Notably, a high abundance of lysine acetylation was observed in the glycolysis/glycogenesis pathways, and the acetylation of glyceraldehyde 3-phosphate dehydrogenase might facilitate ATP production. Subsequent investigation into acetylation modifications associated with deep-sea adaptation revealed the specific identification of key acetylated proteins. Among these, the adaptation of cold seep clam hemoglobin and heat shock protein to high hydrostatic pressure and low temperature might involve an increase in acetylation levels. Acetylation of arginine kinase might be related to ATP production and interaction with symbiotic bacteria. Myosin heavy chain (Ama01085) has the most acetylation sites and might improve the actomyosin system stability through acetylation. Further validation is required for the acetylation modification from Vesicomyidae clams.ConclusionA novel comparative analysis was undertaken to investigate the acetylation of lysine in Vesicomyidae clams, yielding novel insights into the regulatory role of lysine acetylation in deep-sea organisms. The findings present many potential proteins for further exploration of acetylation functions in cold seep clams and other deep-sea mollusks.

New Insights into Fish Diversity in the Yellow and Bohai Seas Based on Environmental DNA Technology

Marine biodiversity is increasingly threatened by overfishing and marine pollution. A comprehensive understanding of the biodiversity in the Yellow and Bohai Seas is essential for resource conservation. This study conducted a large-scale survey of fishery resources in the Yellow and Bohai Seas to investigate fish community structure and diversity using eDNA technology. The results showed that 57 and 65 fish species were recorded in spring and summer, respectively, with 46 species identified in both seasons. A total of nine dominant species were identified in spring, mainly belonging to Perciformes, while seven dominant species were identified in summer, primarily from Clupeiformes. In different regions, no significant differences in fish α diversity were observed between spring and summer. However, significant seasonal differences were found in both α and β diversity. At the spatial level, fish species in the Yellow and Bohai Seas occupied similar ecological niches. However, at the temporal level, there are certain differences in the ecological niches of fish communities between seasons. Phylogenetic diversity showed no significant differences at the spatial scale, yet notable seasonal variations were observed at the temporal scale, with spring (661.46) significantly exceeding summer (540.30). The Mantel test indicated that nitrate and salinity were key environmental factors influencing α diversity. RDA analysis revealed that the dominant species in spring were mainly influenced by chlorophyll-a and water temperature, while those in summer were mainly affected by water depth, nitrite, water temperature, and salinity.