Physical-Chemical Characteristic and Trophic Status of Some Small Lakes in Ciliwung Watershed, West Java Indonesia

Small lakes are important freshwater resources to support the quality of human life. However, small lakes in the watershed are becoming threatened ecosystems because of increasing land-use changes and anthropogenic activity. The study aimed to determine characteristic physical-chemical parameters and trophic status some small lake in Ciliwung Watershed to support the sustainable management of small lakes in the Ciliwung watershed in preventing eutrophication effects. The data was collected in April and June 2021. Measurement and analysis of water quality parameters were conducted by insitu and Laboratory. Some parameters were not in accordance with the Government Regulation number 22/2021 for class II water quality criteria (WQC), including TSS (>50 mg.L-1)., TP (>0.03 mg.L-1), COD (>25 mg.L-1) and DO (<3 mg.L-1), especially for Lake Sunter and Lake Cincin.There are two groups of lakes based on water quality and trophic status. Lake Telaga Warna Lake Cikaret, and Lake Cilodong were classified as eutrophic while lake Sunter and Lake Cincin were classified as hypereutrophic lake Lake Telaga Warna, Lake Cikaret, and Lake Cilodong, located at the upper and middle watershed, are eutrophic, characterized by deeper bottom and higher Secchi depth. At the lower watershed, Lake Sunter and Lake Cincin are hypereutrophic characterized by higher nutrients (TN and TP), COD, temperature, conductivity, salinity, and TDS. The downstream area was a densely populated area that contributed high pollution from upstream and middle of Ciliwung watershed.

Evaluation of the physico-chemical state of the soil contaminant isolate indigenous bacterial species

The aim of the study is to isolate indigenous bacterial species which have the ability to degrade crude oil. Samples were collected from an oil polluted site in Ejama-Ebubu Eleme Rivers state. The samples were taken from five spot (A-E), of depth 0-15 (A1– E1) and 15-30 (A2– E2) in sterile polyethylene bags, using appropriate equipment, then taken to the laboratory for analysis, Physicochemical parameters such as pH, nitrate, sulphate, phosphate, total petroleum hydrocarbon (TPH), poly aromatic hydrocarbon (PAH), salinity, temperature, conductivity and heavy metals (iron, zinc, nikel, lead, chromium) were determined, The THB count was determined using the spread plate method on nutrient agar. Soil, sediment and water physicochemical parameters determined indicated that the samples had been exposed to hydrocarbon contamination. The Gram negative bacteria belonging to the genus pseudomonas is the most frequent. Other genera isolated were Nocardia, Micrococcus,Chromobacterium, Burkholdia, Corynebacterium. The study revealed the presence of petroleum hydrocarbons in the Ejama_Ebubu site as well as known genera of hydrocarbon utilizing bacteria. The biases associated with culture-dependent microbial enumeration techniques may limit the full description of the bacterial diversity in Ejama-Ebubu site. From the study, it is concluded that microorganisms that can degrade hydrocarbons are found in oil contaminated soil and can easily be isolated from these contaminated sites, although it is very difficult to work with aromatic hydrocarbons due to their volatility and toxic effects.

Genotyping and multivariate regression trees reveal ecological diversification within the Microcystis aeruginosa complex along a wide environmental gradient

Addressing the ecological and evolutionary processes underlying biodiversity patterns is essential to identify the mechanisms shaping community structure and function. In bacteria, the formation of new ecologically distinct populations (ecotypes) is proposed as one of the main drivers of diversification. New ecotypes arise when mutations in key functional genes or acquisition of new metabolic pathways by horizontal gene transfer allow the population to exploit new resources, permitting their coexistence with the parental population. We previously reported the presence of microcystin-producing organisms of the Microcystis aeruginosa complex (toxic MAC) through an 800 km environmental gradient ranging from freshwater to estuarine-marine waters in South America. We hypothesize that the success of toxic MAC in such a gradient is due to the existence of very closely related populations that are ecologically distinct (ecotypes), each specialized to a specific arrangement of environmental variables. Here, we analyzed toxic MAC genetic diversity through qPCR and high-resolution melting analysis (HRMA) of a functional gene ( mcyJ , microcystin synthetase cluster). We explored the variability of the mcyJ gene along the environmental gradient by multivariate classification and regression trees ( m CART). Six groups of mcyJ genotypes were distinguished and associated with different combinations of water temperature, conductivity and turbidity. We propose that each mcyJ variant associated to a defined environmental condition is an ecotype (or species) whose relative abundances vary according to their fitness in the local environment. This mechanism would explain the success of toxic MAC in such a wide array of environmental conditions. Importance Organisms of the Microcystis aeruginosa Complex form harmful algal blooms (HABs) in nutrient-rich water bodies worldwide. MAC HABs are difficult to manage owing to the production of potent toxins (microcystins) that resist water treatment. Besides, the role of microcystins in the ecology of MAC organisms is still elusive, meaning that the environmental conditions driving the toxicity of the bloom are not clear. Furthermore, the lack of coherence between morphology-based and genomic-based species classification makes it difficult to draw sound conclusions about when and where each member species of the MAC will dominate the bloom. Here, we propose that the diversification process and success of toxic MAC in a wide range of waterbodies involves the generation of ecotypes, each specialized in a particular niche, whose relative abundance varies according to its fitness in the local environment. This knowledge can improve the generation of accurate prediction models of MAC growth and toxicity, helping to prevent human and animal intoxication.

Study on Low Temperature Conduction Mechanism of Al Doped ZnO/SiO2/ P-Si Heterojunction

The 3 at% Al doped ZnO thin films were deposited on p-Si substrate with a native SiO2 layer by spray pyrolysis method. Low temperature conduction behaviors were studied by analysis of impedance spectroscopy and low temperature ac conductivity. The results of impedance spectroscopy showed that the grain boundaries contributed to the resistivity of Al doped ZnO/SiO2/p-Si heterojunction. The calculated activation energy was 0.073 eV for grain boundaries. The equivalent circuit to demonstrate the electrical properties of Al doped ZnO/SiO2/p-Si heterojunction was a series connection of two parallel combination circuits of a resistor and a universal capacitor. Low temperature ac conductivity measurements indicated that the conductivity increased with temperature. Low temperature conductivity mechanism was electron conductivity, and the activation energy was 0.086 eV.

Trait-environment relationship in tadpoles of the southern Atlantic Forest

Environmental predictors select individuals by their functional traits, shaping the anuran assembly patterns. Individuals respond to environmental filters that can be on a local or regional scale.In this study, we investigated the association between local (water and microhabitat) and landscape variables and the morphological traits of tadpoles of ponds and streams. The study was conducted in the southern region of the Brazilian Atlantic Forest. We sampled 28 waterbodies and recorded 22 anurans species. We performed RLQ and fourth-corner analyses to determine the patterns of trait-environment relationships and determine which environmental and landscape variables influence the morphological characteristics of tadpoles from streams and ponds. We found that the morphological traits of tadpoles are influenced mainly by physicochemical and microhabitat attributes, being distinct between ponds and streams. In ponds, water depth, pH, and the presence of vegetation influence the morphological traits of the tadpoles, while in the streams water pH, temperature, conductivity, total alkalinity, Alk HCO3, and microhabitat variables played a major role in defining the traits. Our results indicate that local components of habitat (water characteristics and microhabitat) influence functional traits of tadpoles in both ponds and streams, especially those supposedly related to locomotory, foraging and prey-detection abilities.

Measuring and tailoring Li-ion interfacial transport in hybrid solid electrolytes

Development of commercial solid-state batteries so far been hindered by the individual limitations of inorganic and organic solid-electrolytes, motivating hybrid concepts. However, room-temperature performance of hybrid-solid electrolytes is still insufficient in terms of ion conductivity, where especially the role and impact of the inorganic and organic interphases is largely unexplored. A key challenge is to assess the Li-ion transport over the interfaces directly and relate this to the surface chemistry. Here the lithium-ion conductivity in hybrid-solid electrolytes, the interface structure and Li+ interface transport was investigated by state-of-art solid-state nuclear magnetic resonance methodologies. In a hybrid-solid Polyethylene oxide polymer – inorganic electrolyte, two representative types of ionic liquids, having a different miscibility with the polymer, were used as a benchmark to tailor the local environment at the interface between the inorganic and organic solid electrolytes species. The poor miscibility ionic liquid wets the polymer-inorganic interface and raises the local polarizability, thereby lowering the diffusional barrier, which activates the high conductivity of the inorganic solid-electrolyte, resulting in and overall room temperature conductivity of 0.25 mS/cm. A very high critical current density of 0.25 mA/cm2 versus a Li-metal anode is achieved, demonstrating improved stability, and a LiFePO4 – Li-metal full solid-state cell can be cycled at room temperature at an Coulombic efficiency of 99.9%. The local interface environment between the solid electrolyte phases in hybrid solid electrolytes, is thus demonstrated to be the bottleneck and tailoring the interface properties appears a viable route towards the design of highly conducting hybrid-solid electrolyte concepts.

Water Quality of Rooftop Rainwater Harvesting System (MyRAWAS)

Prolonged drought, population growth and water demand for various purposes have increased the water scarcity issue. To overcome this issue, a rainwater harvesting system can be utilized as an alternative for clean water supply. A rainwater harvesting system is a method of collecting rainwater from man-made surfaces such as rooftops and constructed surfaces and can be used for various sectors including household, agricultural and commercial. This study was conducted to determine the quality of rainwater harvested collected directly from rooftop. The quality of the rooftop rainwater was taken in three consecutive months and the water quality for before and after treatment was measured and compared. Commercial activated carbon was used to treat the rainwater obtained from the rooftop. The water quality was compared with the Water Quality Index (WQI) and the National Water Quality Standards (NWQS). The parameters involved are pH, temperature, conductivity, dissolved oxygen (DO), total suspended solids (TSS), ammoniacal nitrogen (NH3-N), biochemical oxygen demand (BOD), chemical oxygen demand (COD),E.coli and total coliform bacteria. The results showed that the total value of WQI before and after treatment was 86.3 ± 8.963 and 87.6±2.081, respectively. Positive correlations were found for parameter NH3-N, COD and pH, while paired T-test showed a significant in the COD and the presence of bacteria. Total Coliform is still at a safe level by NWQS with the average value and the standard deviation for before and after treatment were 38.11 ± 13.960 cfu/ml and 10.33 ± 6.671 cfu/ml, respectively.

Abundance and Diversity of Snails in Relation to Physicochemical Parameters along Kwadom Stream, Gombe State, Nigeria

Aims: The aim of the study is to investigate the abundance and diversity of snails along Kwadom stream, Gombe state, Nigeria. Study Design: Snails were collected using a benthic scoop net with mesh size of 0.2 mm and hand picking from three sampling stations (home, farmlands, and fishponds sites) along Kwadom stream; between 6:30 am to 11:00 am weekly. In addition, physicochemical parameters (temperature, dissolved oxygen, conductivity, alkalinity, water depth and pH) were measured fortnightly to determine their effect on the diversity of snail species. Place and Duration of Study: The study was conducted along Kwadom stream in Yamaltu Deba Local Government Area of Gombe State, Nigeria from March to July 2021. Methodology: Snails were collected from each of the three stations and identified to species level using hand lens and taxonomy keys. Water physicochemical parameters: temperature, dissolved oxygen, conductivity, alkalinity, water depth and pH were measured using standard method. General linear models (GLM) were used to compare the abundance and diversity of the snails across the sampling station, as well as the effect of physicochemical parameters on the diversity of snails. Results: 160 individual snails were recorded from 11 species, including Biomphalaria pfeifferi– the intermediate host of Schistosoma mansoni. The result showed there was a significant difference in the abundance of snails (p<0.01) across the three study sites – home site 68 (42.5%), farmlands site 56 (35%) and fishpond site 36 (22.5%). The home site had a higher diversity of snail species (p<0.01) relative to the farmlands and fishponds sites. Temperature, conductivity, and alkalinity had a significant effect on the diversity of snails. Conclusion: Overall, Kwadom stream harbors many individual snail species, suggesting the need for educating the public on the mode of transmission of diseases that are caused by these snails.

Fate of turbid glacial inflows in a hydroelectric reservoir

Turbidity from glacial meltwater limits light penetration with potential ecological consequences. Using profiles of temperature, conductivity, and turbidity, we examine the physical processes driving changes in the epilimnetic turbidity of Carpenter Reservoir, a long and narrow, glacier-fed reservoir in southwest British Columbia, Canada. Following the onset of permanent summer stratification, the relatively dense inflows plunged into the hypolimnion, and despite the high glacial load entering the reservoir, the epilimnion cleared due to particle settling. Using a one-dimensional (longitudinal) diffusion equation for a decaying substance to describe the variation in epilimnetic turbidity, we obtain two nondimensional parameters: the epilimnetic inflow parameter, $$\mathcal {I}$$ I , a measure of the turbidity flux into the epilimnion; and the dispersion parameter, $${\mathcal {D}}$$ D , a measure of longitudinal dispersion. In the case of Carpenter Reservoir: $$\mathcal {I}\ll 1$$ I ≪ 1 , indicating that turbidity declines over the summer; and $${\mathcal {D}}\ll 1$$ D ≪ 1 , indicating a strong gradient in turbidity along the epilimnion. Using our theoretical formulation of epilimnetic turbidity variations in conjunction with monthly field surveys, we compute the particle settling velocity ($${\sim}{0.25}\,{\hbox {m}\,\hbox {d}^{-1}}$$ ∼ 0.25 m d - 1 ), the longitudinal dispersion coefficient (50–70 $${\hbox {m}^{2}\,\hbox {s}^{-1}}$$ m 2 s - 1 ), and the flux of turbid water into the epilimnion ($${\sim }1{\%}$$ ∼ 1 % of the total inflow). Our approach is applicable to other reservoirs and can be used to investigate changes in turbidity in response to changes in $$\mathcal {I}$$ I and $${\mathcal {D}}$$ D .

Evaluating the Performance of Machine Learning Approaches to Predict the Microbial Quality of Surface Waters and to Optimize the Sampling Effort

Exposure to contaminated water during aquatic recreational activities can lead to gastrointestinal diseases. In order to decrease the exposure risk, the fecal indicator bacteria Escherichia coli is routinely monitored, which is time-consuming, labor-intensive, and costly. To assist the stakeholders in the daily management of bathing sites, models have been developed to predict the microbiological quality. However, model performances are highly dependent on the quality of the input data which are usually scarce. In our study, we proposed a conceptual framework for optimizing the selection of the most adapted model, and to enrich the training dataset. This frameword was successfully applied to the prediction of Escherichia coli concentrations in the Marne River (Paris Area, France). We compared the performance of six machine learning (ML)-based models: K-nearest neighbors, Decision Tree, Support Vector Machines, Bagging, Random Forest, and Adaptive boosting. Based on several statistical metrics, the Random Forest model presented the best accuracy compared to the other models. However, 53.2 ± 3.5% of the predicted E. coli densities were inaccurately estimated according to the mean absolute percentage error (MAPE). Four parameters (temperature, conductivity, 24 h cumulative rainfall of the previous day the sampling, and the river flow) were identified as key variables to be monitored for optimization of the ML model. The set of values to be optimized will feed an alert system for monitoring the microbiological quality of the water through combined strategy of in situ manual sampling and the deployment of a network of sensors. Based on these results, we propose a guideline for ML model selection and sampling optimization.