Pond Samples Research Articles

Viromic and Metagenomic Analyses of Commercial Spirulina Fermentations Reveal Remarkable Microbial Diversity.

Commercially produced cyanobacteria preparations sold under the name spirulina are widely consumed, due to their traditional use as a nutrient-rich foodstuff and subsequent marketing as a superfood. Despite their popularity, the microbial composition of ponds used to cultivate these bacteria is understudied. A total of 19 pond samples were obtained from small-scale spirulina farms and subjected to metagenome and/or virome sequencing, and the results were analysed. A remarkable level of prokaryotic and viral diversity was found to be present in the ponds, with Limnospira sp. and Arthrospira sp. sometimes being notably scarce. A detailed breakdown of prokaryotic and viral components of 15 samples is presented. Twenty putative Limnospira sp.-infecting bacteriophage contigs were identified, though no correlation between the performance of these cultures and the presence of phages was found. The high diversity of these samples prevented the identification of clear trends in sample performance over time, between ponds or when comparing successful and failed fermentations.

Exploration and Molecular Identification of Proteolytic Bacteria as Probiotic Candidates from Shrimp Ponds in West Sumatra, Indonesia.

<b>Background and Objective:</b> The existence of intensive shrimp aquaculture faces serious challenges in the form of a decrease in pond water quality due to overfeeding. Efforts are needed to improve pond water quality by utilizing proteolytic bacterial isolates to break down suspended or accumulated feed on the pond bottom. The research aims to find proteolytic bacterial isolates from pond sediments and the digestive tract of shrimp (<i>Litopenaeus vannamei</i>). <b>Materials and Methods:</b> The materials needed are pond sediment samples, shrimp digestive tract, seawater complete agar (SWCA) medium and skim milk agar medium (SMA). The study used survey methods to determine sampling locations and continued with experimental methods in the laboratory. Nine isolates were obtained from pond sediments and two bacterial isolates were from the shrimp digestive tract. <b>Results:</b> The proteolytic potency test showed that two isolates from pond sediments and one isolate from the digestive tract of shrimp were positive for proteolytic. The largest proteolytic index value reached 6.357. Molecular identification by analyzing the <i>16S rRNA</i> gene sequence shows that PC23 isolate is closely related to the bacterium <i>Exiguobacterium indicum </i>strain KR6 with percent identity 99.44-99.58% and PU32 isolate with <i>Bacillus cereus</i> strain 125 with percent identity 100%. <b>Conclusion:</b> The bacteria obtained can be used as probiotic candidates for the future are <i>Exiguobacterium indicum</i> strain KR6 and <i>Bacillus cereus</i> strain 125.

Sources and Prevalence of Cyclospora cayetanensis in Southeastern U.S. Growing Environments

Recent cyclosporiasis outbreaks associated with fresh produce grown in the United States highlight the need to better understand Cyclospora cayetanensis prevalence in U.S. agricultural environments. In this study, C. cayetanensis occurrence was assessed in municipal wastewater sludge, on-farm portable toilets, irrigation pond water, and spent packing house dump tank water in a Southeastern Georgia growing region over two years. Detection of the C. cayetanensis 18S rRNA qPCR gene target in pond samples was 0%, 28%, and 42% (N = 217) depending on the detection definition used, and ≤1% in dump tank samples (N = 46). However, no qPCR detections were confirmed by sequencing, suggesting false detection occurred due to cross-reactions. C. cayetanensis qPCR detections were confirmed in 9% of wastewater sludge samples (N = 76). The human-specific fecal markers HF183 and crAssphage were detected in 33% and 6% of pond samples, respectively, and 4% and 0% of dump tank samples, respectively. Despite community Cyclospora shedding and evidence of human fecal contamination in irrigation water, there was no correlation between C. cayetanensis and HF183 qPCR detections, further supporting that 18S gene target qPCR amplifications were due to cross−reactions. When evaluating C. cayetanensis qPCR environmental detection data, the impact of assay specificity and detection criteria should be considered. Moreover, additional sequence-based testing may be needed to appropriately interpret Cyclospora qPCR environmental data.

The Biochemical Composition and Quality of Adult Chinese Mitten Crab Eriocheir sinensis Reared in Carbonate-Alkalinity Water

Saline–alkaline aquaculture has become an important breakthrough in expanding the space available for aquaculture in China. However, the biochemical composition and quality of Eriocheir sinensis reared in carbonate alkalinity water are still unclear. Therefore, this study investigated the edible yield, coloration, and nutritional and flavor quality of Eriocheir sinensis. A significantly lower gonadosomatic index (GSI), meat yield (MY), and total edible yield (TEY) were detected in intensive pond (IP) samples than those in semi-intensive reed wetland (SIWR) (p < 0.05). Six color parameters in the hepatopancreas (p < 0.05) differed between IP and SIRW. The contents of crude protein and fat in the female hepatopancreas of IP were significantly higher than those in SIRW (p < 0.05). The concentrations of total monounsaturated fatty acids (∑MUFA), total essential fatty acids (∑EFA), and hypocholesterolaemic/hypercholesterolaemic ratio (h/H) in the female edible tissues checked were higher in IP than those in SIRW, with significant differences including ∑MUFA in the hepatopancreas and ovary, ∑EFA in the muscle, and h/H in the ovary (p < 0.05). Higher total free amino acid (∑FAA) contents of muscle were detected in SIRW than that in IP samples. Significantly higher K, Ca, Mg, Fe, and Zn contents in the ovary were detected in SIRW samples compared to IP (p < 0.05). Overall, Eriocheir sinensis reared in carbonate-alkalinity water is an important source of nutrients.

Percentage Incidences of Bacteria in Mahseer (Tor putitora), Silver carp (Hypophthalmichthys molitrix) Fish Collected from Hatcheries and Local Markets of District Malakand and Peshawar of Khyber Pakhtunkhwa, Pakistan.

Fish is the main source of animal protein for human diet. The aim of this study was to find out prevalence of pathogenic bacteria of two selected economically important fish of Pakistan namely Mahseer (Tor putitora) and Silver carp (Hypophthalmichthys molitrix). Live fish samples from hatcheries and dead fish samples from different markets of study area were randomly collected. The fish samples were analyzed for isolation, identification and prevalence of bacteria. The isolated bacteria from study fish were identified through biochemical test and about 10 species of pathogenic bacteria were identified including the pathogenic bacteria to human and fish namely, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus iniae, Serratia spp. Citrobacter spp. Stenotrophomonas spp. Bacillus spp. and Salmonella spp. The bacterial percentage frequency of occurrence in Silver carp and Mahseer fish showed Pseudomonas aeruginosa 21.42%, Staphylococcus epidermidis 17.85%, Escherichia coli 11.90%, Staphylococcus aureus 9.52%, Citrobacter spp. 9.52%, Serratia spp. 8.33%, Streptococcus iniae 7.14%, Stenotrophomonas spp. 5.95%, Bacillus spp. 4.76% and Salmonella spp. 3.57%. The study revealed that Fish samples of Mahseer and Silver carp that were collected from markets have found more isolates (10 bacterial species) than did the fresh fish pond samples (03 bacterial species) of hatcheries. The occurrence of pathogenic bacteria in study fish showed risk factor for public health consumers.

Comparison of high‐throughput sequencing methods for bacterial microbiota profiling in catfish aquaculture

AbstractObjectiveBacterial community profiling in aquaculture can be useful for monitoring environmental conditions that may lead to disease outbreaks, understanding the impact of dietary treatments on fish health, and identifying microbes that have potential as probiotics. Microbiota characterization is commonly performed with high‐throughput sequencing using short‐read platforms (i.e., Illumina) targeting variable regions of the bacterial 16S ribosomal RNA (rRNA) gene. Long‐read platforms (i.e., Oxford Nanopore Technologies [ONT]) enable sequencing of full‐length 16S rRNA genes. While short‐read platforms are highly accurate, long‐read platforms sacrifice sequence quality in exchange for longer read lengths.MethodsHerein, a typical short‐read approach (Illumina MiSeq; V4 region of 16S rRNA gene) was compared with two near‐full‐length 16S rRNA gene ONT protocols (ONT Custom and ONT 16S). Sequencing was performed on a mock community composed of fish‐relevant bacteria, in addition to samples (digesta, gill, skin) obtained from 10 hybrid catfish (female Channel Catfish Ictalurus punctatus × male Blue Catfish I. furcatus) and their environment (pond and holding tank). Fish were euthanized with either an overdose of MS‐222 or cranial concussion and subsequent pithing to enable comparisons of these sequencing protocols in the context of a realistic experimental design.ResultThe ONT Custom protocol best recapitulated the theoretical composition of the mock community, followed by the ONT 16S and Illumina MiSeq protocols. Phylum‐level composition was consistent within sample type across sequencing methods. However, at lower levels there were biases for several taxa, particularly in pond samples. Euthanasia method also appeared to introduce differences, primarily on the cutaneous communities. The three sequencing methods consistently identified significant differences between euthanasia methods, with Illumina MiSeq revealing the greatest differences. While all strategies performed comparably for digesta, skin, and water samples, the ONT strategies underperformed for gill samples.ConclusionDepending on application, results indicate that near‐full‐length 16S rRNA gene nanopore sequencing is a viable option for aquaculture microbiota studies.

Phycoremediation of crude oil polluted water from selected water sources in Ogoniland, Rivers State, Nigeria.

Crude oil exploitation in the Niger Delta, particularly in Ogoniland, brought environmental devastation occasioned by petroleum pollution, as farmlands and water sources were destroyed. This study was designed to remediate crude oil contaminated water obtained from water sources in Ogoniland using two green algal species. Thirty water samples were collected from eight different water sources. The samples were analysed for total petroleum hydrocarbon (TPH) using gas chromatography/flame ionization detector (GC/FID). Algal samples were collected from Ogba River and at wetland in Military Hospital Benin, Edo State, Nigeria. The algal samples were identified, screened, optimized and grown in Bold basal medium. Results obtained from the determination of TPH showed that the infiltrated pond (Exc) sample site had the highest concentration among all the sites sampled with 198.8329 μg/L, R2 with 134.1296 μg/L, R1 with 108.9394 μg/L, R3 with 105.8011 μg/L, R4 with 98.442 8 μg/L, the hand-dug wells (Wll) had 9.6586 μg/L while the borehole (Bhl) had the lowest with 1.8310 μg/L. It was deduced that pollution of water sources was principally because of pollutants washed from the soil environment into the open surface water sources via run-off rather than through the seepage from the underground aquifers, incriminating illegal oil mining and artisanal refining. Results obtained from the analysis of algal growth medium indicated that the two algal species were able to absorb the hydrocarbon contaminants, albeit at different rates, corresponding with the algal growth rate. Analysis of algal biomass after 4 weeks of remediation showed that from the initial 10.27 μg/20 mL added to the growth medium, the highest TPH mean value of 0.490 μg/20 mL was extracted from Ulothrix zonata (F.Weber & Mohr) Kützing biomass grown in Exc compared to 0.344 μg/20 mL of TPH extracted from Chlorella sorokiniana Shihira & R.W.Krauss grown in the same sample site. Also, Ulothrix zonata had higher TPH yield 0.023 μg/20 mL in Bhl compared to Chlorella sorokiniana 0.021 μg/20 mL of TPH from the same water source. This result indicated Ulothrix zonata had superior TPH phycoremediation ability to Chlorella sorokiniana. While the present study calls for deployment of the algal species for field trial, it is strongly recommended that crude oil pollution should be discouraged.

Nonbacterial Microflora in Wastewater Treatment Plants: an Underappreciated Potential Source of Pathogens.

Wastewater treatment plants (WWTPs) receive and treat large volumes of domestic, industrial, and urban wastewater containing pathogenic and nonpathogenic microorganisms, chemical compounds, heavy metals, and other potentially hazardous substances. WWTPs play an essential role in preserving human, animal, and environmental health by removing many of these toxic and infectious agents, particularly biological hazards. Wastewater contains complex consortiums of bacterial, viral, archaeal, and eukaryotic species, and while bacteria in WWTP have been extensively studied, the temporal and spatial distribution of nonbacterial microflora (viruses, archaea, and eukaryotes) is less understood. In this study, we analyzed the viral, archaeal, and eukaryotic microflora in wastewater throughout a treatment plant (raw influent, effluent, oxidation pond water, and oxidation pond sediment) in Aotearoa (New Zealand) using Illumina shotgun metagenomic sequencing. Our results suggest a similar trend across many taxa, with an increase in relative abundance in oxidation pond samples compared to influent and effluent samples, except for archaea, which had the opposite trend. Additionally, some microbial families, such as Podoviridae bacteriophages and Apicomplexa alveolates, appeared largely unaffected by the treatment process, with their relative abundance remaining stable throughout. Several groups encompassing pathogenic species, such as Leishmania, Plasmodium, Toxoplasma, Apicomplexa, Cryptococcus, Botrytis, and Ustilago, were identified. If present, these potentially pathogenic species could be a threat to human and animal health and agricultural productivity; therefore, further investigation is warranted. These nonbacterial pathogens should be considered when assessing the potential for vector transmission, distribution of biosolids to land, and discharge of treated wastewater to waterways or land. IMPORTANCE Nonbacterial microflora in wastewater remain understudied compared to their bacterial counterparts despite their importance in the wastewater treatment process. In this study, we report the temporal and spatial distributions of DNA viruses, archaea, protozoa, and fungi in raw wastewater influent, effluent, oxidation pond water, and oxidation pond sediments by using shotgun metagenomic sequencing. Our study indicated the presence of groups of nonbacterial taxa which encompass pathogenic species that may have potential to cause disease in humans, animals, and agricultural crops. We also observed higher alpha diversity in viruses, archaea, and fungi in effluent samples than in influent samples. This suggests that the resident microflora in the wastewater treatment plant may be making a greater contribution to the diversity of taxa observed in wastewater effluent than previously thought. This study provides important insights to better understand the potential human, animal, and environmental health impacts of discharged treated wastewater.

Characterization of a pigmented Brevundimonas sp. isolated from red mud pond samples of a bauxite mine

Aim: The present study aimed to isolate useful bacterial strains of industrial importance from the red mud pond of Utkal Alumina, Odisha, India. Methodology: Samples were collected, serially diluted and spread on Nutrient Agar medium. An orange-colored bacterium was isolated and subjected to molecular characterization through 16S rDNA analysis followed by phylogenetic analysis. The pigment was isolated and characterized through FTIR study. Antimicrobial and radical scavenging activities were also studied. Results: The isolate was identified as Brevundimonas sp. FTIR study showed the pigment to be a beta-carotene, which significantly increased under salt and pH stress, however, was severely affected under metallic stress conditions. The ethanolic extract showed a moderate antibacterial activity. The pigment showeda good radical scavenging activity of approximately 86 % in 30 min. Interpretation: Species of Brevundimonas have not been reported in red mud ponds. The isolated pigment shows a good radical scavenging activity in vitro. It may be useful for cosmetic industry. Key words: Red mud, 16S rDNA, Alkali tolerant, Beta-carotene, Brevundimonas, FTIR spectroscopy

A comprehensive assessment of leachate contamination at a non-operational open dumpsite: mycoflora screening, metal soil pollution indices, and ecotoxicological risks.

The final disposal of municipal solid waste (MSW) in dumpsites is still a reality worldwide, especially in low- and middle-income countries, leading to leachate-contaminated zones. Therefore, the aim of this study was to carry out soil and leachate physicochemical, microbiological, and toxicological characterizations from a non-operational dumpsite. The L-01 pond samples presented the highest physicochemical parameters, especially chloride (Cl; 4101 ± 44.8mg L-1), electrical conductivity (EC; 10,452 ± 0.1 mS cm-1), and chemical oxygen demand (COD; 760 ± 6.6mg L-1) indicating the presence of leachate, explained by its close proximity to the landfill cell. Pond L-03 presented higher parameters compared to pond L-02, except for N-ammoniacal and phosphorus levels, explained by the local geological configuration, configured as a slope from the landfill cell towards L-03. Seven filamentous and/or yeast fungi genera were identified, including the opportunistic pathogenic fungi Candida krusei (4CFU) in an outcrop sample. Regarding soil samples, Br, Se, and I were present at high concentrations leading to high soil contamination (CF ≤ 6). Pond L-02 presented the highest CF for Br (18.14 ± 18.41mgkg-1) and I (10.63 ± 3.66mgkg-1), while pond L-03 presented the highest CF for Se (7.60 ± 1.33mgkg-1). The most severe lethal effect for Artemia salina was observed for L-03 samples (LC50: 79.91%), while only samples from L-01 were toxic to Danio rerio (LC50: 32.99%). The highest lethality for Eisenia andrei was observed for L-02 samples (LC50: 50.30%). The applied risk characterization indicates high risk of all proposed scenarios for both aquatic (RQ 375-909) and terrestrial environments (RQ > 1.4 × 105). These findings indicate that the investigated dumpsite is contaminated by both leachate and metals, high risks to living organisms and adjacent water resources, also potentially affecting human health.

Novel and Highly Sensitive Electrochemical Sensor for the Determination of Oxytetracycline Based on Fluorine-Doped Activated Carbon and Hydrophobic Deep Eutectic Solvents.

Residues of oxytetracycline (OTC), a veterinary antibiotic and growth promoter, can be present in animal-derived foods; their consumption is harmful to human health and their presence must therefore be detected and regulated. However, the maximum residue limit is low, and consequently highly sensitive and accurate detectors are required to detect the residues. In this study, a novel highly sensitive electrochemical sensor for the detection of OTC was developed using a screen-printed electrode modified with fluorine-doped activated carbon (F-AC/SPE) combined with a novel deep eutectic solvent (DES). The modification of activated carbon by doping with fluorine atoms (F-AC) enhanced the adsorption and electrical activity of the activated carbon. The novel hydrophobic DES was prepared from tetrabutylammonium bromide (TBABr) and a fatty acid (malonic acid) using a green synthesis method. The addition of the DES increased the electrochemical response of F-AC for OTC detection; furthermore, it induced preconcentration of OTC, which increased its detectability. The electrostatic interactions between DES and OTC as well as the adsorption of OTC on the surface of the modified electrode through H-bonding and π-π interactions helped in OTC detection, which was quantified based on the decrease in the anodic peak potential (E pa = 0.3 V) of AC. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Under optimum conditions, the calibration plot of OTC exhibited a linear response in the range 5-1500 μg L-1, with a detection limit of 1.74 μg L-1. The fabricated electrochemical sensor was successfully applied to determine the OTC in shrimp pond and shrimp samples with recoveries of 83.8-100.5% and 93.3-104.5%, respectively. In addition to the high sensitivity of OTC detection, the proposed electrochemical sensor is simple, cost-effective, and environmentally friendly.

Speciation and Risk of Heavy Metals in Surface Sediments of Different Types of Water Bodies in Baiyangdian Lake

The morphological characteristics of Cd, Cr, Cu, Ni, Pb, and Zn in sediments were analyzed using an improved BCR extraction method in four water types of Baiyangdian Lake:watercourse, trench, lake surface, and fish pond. The potential ecological risk index, secondary and primary phases, and risk assessment codes were used to systematically assess the pollution level and ecological risk of heavy metals in surface sediments. The results showed that:① the mean contents of heavy metals Cd, Cu, and Zn in the sediments were 0.37, 28.49, and 83.08 mg·kg-1, respectively, 94.91%, 73.91%, and 46.39% of which exceeded the soil background value. ② Cd was dominated by the non-residual fraction (F1+F2+F3) with a fraction ranging from 54% to 97%, whereas Cr was dominated by the residual fraction (F4) with a mass fraction ranging from 87% to 99%. Cu, Ni, Pb, and Zn were mainly in the fraction of residual fraction. In the non-residual fraction, Cu and Ni were mainly in the oxidizable fraction (F3) state, whereas Pb and Zn were mainly in the reducible fraction (F2) state. ③ The RAC risk assessment results showed that there were 68.97%, 39.89%, 54.84%, and 49.78% points in channel, trench, open water, and fish pond samples, respectively, of Cd at high risk. The Cu, Ni, and Pb were at low risk. In general, the overall heavy metal pollution level in Baiyangdian Lake was low, but Cd had ecological risk and high bioavailability in the Fuhe River of the Nanliuzhuang area and the Baigouyin River.

Geogenic enrichment of fluoride in groundwater of hard rock aquifer in fluorosis prevalent area of Balangir district, Odisha, India

Hydrogeochemical characterization of groundwater has been carried out in a hard rock aquifer from Balangir district, a fluorosis-affected area of Odisha, India with the aim of understanding the sources and processes controlling fluoride (F−) enrichment. A total of 37 groundwater (tube wells) and 7 surface water (pond) samples were collected during the pre-monsoon period. Groundwaters are mostly categorized as moderate to very hard water types with alkaline nature. The enhanced Na+ and HCO3− concentration in groundwater is mostly a result of silicate weathering. The F− concentration in groundwater ranged from 0.4 to 4.29 mg/l, with 38% of samples exceeded the drinking water limit (1.5 mg/l; as prescribed by the World Health Organization, 2011), in contrast to very low F− (<0.9 mg/l) in surface water. High F− concentrations in underlying granitic bedrocks (up to 700 mg/kg), which spatially corresponds to F− rich groundwater, suggest that lithological composition is the main control of F−. Fluoride-rich waters are mostly Na–HCO3 type, followed by mixed Na–Ca–HCO3 (Cl) type with Na+/Ca2+ ratio >1. The significant positive correlations of F− with Na+, HCO3−, and pH indicate that the weathering of sodium-rich silicate minerals and increase of pH mobilizes F− ion. Geochemical modeling indicates that the activity of F− in groundwater increased by precipitation of calcite, dolomite, and aragonite. Fluoride risk assessment indicates that 38% of groundwater samples can cause a high prevalence of dental fluorosis with children being at greater risk than adults. Henceforth, it is advisable to treat this contaminated groundwater before consumption or provide alternative drinking water to avoid further fluorosis risks in the concerned area.

Assessing recharge process in plain catchments using isotopic and hydrochemical techniques

In order to increase the sustainability and conservation of water resources, a joint approach of isotopic and hydrochemical techniques was attempted to identify and quantify water sources and favourable recharge areas that would explain the integral functioning of a typically plain catchment. Chloride and δ18O and δ2H were measured in rain, groundwater, and pond samples. Chloride mass balance approach was applied to calculate the recharge and mixed water calculation was carried out using conservative tracers. Also, the local meteoric water line was calculated. Depleted isotopic and slightly progressive chloride contents are observed and they are grouped around to the local meteoric water line in the upper part and in the west of the lower catchment. In the East lower area 20% of recharge is calculated; isotopes are more enriched and lower concentration of chloride are observed. Depleted isotopic fingerprint and low salinity concentration for Ballenera pond were identified in a well close to it. This work demonstrates that in very flat zones, small changes in the hydrologic fluxes can impact on the water table of surface waters and groundwaters, leading to establish very local recharge zones that hardly can be recognized in large scale or esatfrequency of measurement, but can quiet easily be identified when chemical conservative tracers and water stable isotopes are used. Also, isotopic data demonstrate the importance of shallow wetlands as certain recharge areas to the regional aquifer, becoming areas of high groundwater vulnerability.

The true picture of environmental DNA, a case study in harvested fishponds

The application of environmental DNA (eDNA) metabarcoding has revolutionised large scale biodiversity monitoring of aquatic ecosystems. Validation studies have been performed mainly in laboratories and mesocosm experiments, however large-scale field experiments are necessary to verify the robustness of eDNA based monitoring for more specific applications and different environmental conditions. Here, eDNA samples were collected from three fishponds with high fish density and broad species diversity during summer and autumn. This sampling design included a large number of spatial replicates evenly spaced across the pond surface and samples from the inflow, while pooled samples were used to test the effect of filtration volumes on detectability. Most common species were detected using eDNA, but rare species were often missed out under these high stocking densities. Average read counts and site occupancy positively correlated strongly with species abundance and biomass, with the exception of samples affected by PCR inhibition. Higher diversity detections were observed in autumn compared to summer samplings and in running compared to standing water. Fish communities detected in pooled samples reflect the overall community structure, and the species detectability increases with higher filtration volumes. This work highlights how eDNA based surveys can be optimised based on sampling conditions to achieve the highest overall detection, which has important implications for applying this method to aid management and policy initiatives.

Speciation Distribution and Influencing Factors of Heavy Metals in Rhizosphere Soil of Miscanthus Floridulus in the Tailing Reservoir Area of Dabaoshan Iron Polymetallic Mine in Northern Guangdong

Through field investigation and experimental analysis, the forms, contents and distribution of heavy metals (Zn, Pb, Cu, Cd, Ni, Cr) in rhizosphere and non-rhizosphere soils of Miscanthus floridulus growing everywhere in Tielongwei mine pond (sample plot 1), Caoduikeng tailings pond (sample plot 2), Donghua tailings pond (sample plot 3) and Small tailings pond (sample plot 4) in Dabaoshan, Guangdong Province were studied. The results showed that the main forms and distributions of heavy metals in rhizosphere and non-rhizosphere soils are basically the same, which shows that the mineral content accounts for most of the total amount of heavy metals, while the exchange content is low. Compared with non-rhizosphere soil, the proportion of exchangeable and organic heavy metals in rhizosphere soil increased significantly, in which the proportion of organic-bound Cu increased by 53.25%, the proportion of organic-bound Cd and Pb increased by more than 17%, and the proportion of Zn increased by 5.67%. At the same time, the contents of carbonate-bound and iron manganese oxide-bound decreased. Statistical analyses showed that the morphological distribution of Zn, Pb, Cu, Cd, Ni and Cr in rhizosphere soil was closely related to soil pH value, organic matter content, plant growth and other factors. The results of this study provided a basis for the restoration of heavy metal-contaminated sites by Miscanthus.

Evaluating the performance of conventional DAF and PosiDAF processes for cyanobacteria separation at a pilot plant scale

Abstract In this work, a commercially available water treatment polymer poly(N,N-diallyl-N,N-dimethylammonium chloride) (PDADMAC) and a hydrophobically modified polymer (HMP) designed to adhere to bubble surfaces were applied for the first time in the novel Posi-dissolved air flotation process (PosiDAF) that uses polymer-modified bubbles, at pilot-scale for the treatment of waste stabilisation pond samples rich in algae. It was found that PDADMAC in PosiDAF gave comparable removal to that achieved using conventional DAF at &amp;gt;95% cell separation. Furthermore, the float layer was more uniform and thicker with up to 8% solid contents compared to conventional DAF, which comprised discrete floc clusters with an average solid concentration of ∼4.1%. In contrast to the use of PDADMAC, the application of the HMP did not achieve similarly good separation at pilot scale. It was hypothesised that this may be due to the micellisation of the HMP on the bubble surface, creating unstable bubbles that coalesced and prevented polymer–bubble–cell interactions, which are crucial for effective cell separation. On comparison of the costs of PosiDAF and conventional DAF, it was found that PosiDAF resulted in cost-savings of up to 74% due to low chemical consumption. In summary, PosiDAF reduced chemical cost and increased solid contents in the metal-free float.

Comparison of planktonic bacterial communities indoor and outdoor of aquaculture greenhouses.

Greenhouses are widely used in agriculture systems to shield crops from unfavourable weather to achieve a year-round food supply. In recent years, aquaculture ponds have been placed in greenhouses in many regions. The impacts of the greenhouses on planktonic bacterial communities should be uncovered. In this study, two polyolefin film greenhouses accommodating aquaculture ponds were established and planktonic bacterial communities were compared from samples taken in aquaculture ponds inside and outside the greenhouses, using Illumina 16S rRNA sequencing. The results showed there were significant variations in bacterial community structure between indoor and outdoor samples. Obvious differences were also found between two greenhouses, whereas the differences in indoor samples were weaker than outdoor samples. Significantly higher temperature (in summer), pH and permanganate index were found in the outdoor pond samples. Results of redundancy analysis showed that Proteobacteria and Bacteroidota were positively related to the dissolved oxygen, total nitrogen and total phosphorus, and Actinobacteriota were positively related to pH, temperature and permanganate index, whereas Cyanobacteria were positively related to the salinity, conductivity, total dissolved solids and ammonia nitrogen. The results of this study revealed that greenhouses significantly influenced planktonic bacterial communities in aquaculture ponds. This study isexpected to provide a scientific basis for aquaculture in greenhouses.

Wastewater-Based Epidemiological Surveillance for SARS-CoV-2

Abstract Background: Similar to enteric or diarrheal coronaviruses (CoV), SARS-CoV-2 is also known for its gastrointestinal and fecal shedding even in asymptomatic Covid-19 individuals. Methods: An online literature search was conducted using Google scholar. PubMed, Europe PMC, Medline etc. to collect published articles on the countrywide detection of SARS-CoV-2 in various water and wastewater sources. Result: Ample of recent studies showed detection SARS-CoV-2 RNA in municipal and hospital wastewater as well as river and pond samples, suggesting its potential waterborne spread. Most of the reports used the molecular method (RT-qPCR) to detect the viral RNA, whereas some also quantified the RNA. Notably, the analyzed studies used different methods of water sampling and virus concentration, chose different gene-targets for RT-qPCR and presented RNA quantity as genome copy/mL or log10. Several of studies also described different physical and chemical methods of decontamination or inactivation of SARS-CoV-2 in treated water. Overall, while considerable amount of viral RNA was reported widely, couple of study tested the viability and infectivity of the retrieved particles in cultured cells. Conclusion: The available data on occurrences of SARS-CoV-2 in various water sources suggest an urgent need of wastewater-based epidemiological surveillance as an early-warning tool for COVID-19. This would help prevent unexpected contamination and safeguard drinking water. Keywords: SARS-CoV-2; Covid-19; Fecal shedding, Waterborne infection, Wastewater surveillance.

Reliability of environmental DNA surveys to detect pond occupancy by newts at a national scale

The distribution assessment and monitoring of species is key to reliable environmental impact assessments and conservation interventions. Considerable effort is directed towards survey and monitoring of great crested newts (Triturus cristatus) in England. Surveys are increasingly undertaken using indirect methodologies, such as environmental DNA (eDNA). We used a large data set to estimate national pond occupancy rate, as well as false negative and false positive error rates, for commercial eDNA protocols. Additionally, we explored a range of habitat, landscape and climatic variables as predictors of pond occupancy. In England, 20% of ponds were estimated to be occupied by great crested newts. Pond sample collection error rates were estimated as 5.2% false negative and 1.5% false positive. Laboratory error indicated a negligible false negative rate when 12 qPCR replicates were used. Laboratory false positive error was estimated at 2% per qPCR replicate and is therefore exaggerated by high levels of laboratory replication. Including simple habitat suitability variables into the model revealed the importance of fish, plants and shading as predictors of newt presence. However, variables traditionally considered as important for newt presence may need more precise and consistent measurement if they are to be employed as reliable predictors in modelling exercises.