Algal Growth Research Articles

A Machine Learning and Remote Sensing‐Based Model for Algae Pigment and Dissolved Oxygen Retrieval on a Small Inland Lake

AbstractExcessive algae growth can lead to negative consequences for ecosystem function, economic opportunity, and human and animal health. Due to the cost‐effectiveness and temporal availability of satellite imagery, remote sensing has become a powerful tool for water quality monitoring. The use of remotely sensed products to monitor water quality related to algae and cyanobacteria productivity during a bloom event may help inform management strategies for inland waters. To evaluate the ability of satellite imagery to monitor algae pigments and dissolved oxygen conditions in a small inland lake, chlorophyll‐a, phycocyanin, and dissolved oxygen concentrations are measured using a YSI EXO2 sonde during Sentinel‐2 and Sentinel‐3 overpasses from 2019 to 2022 on Lake Mendota, WI. Machine learning methods are implemented with existing algorithms to model chlorophyll‐a, phycocyanin, and Pc:Chla. A novel machine learning‐based dissolved oxygen modeling approach is developed using algae pigment concentrations as predictors. Best model results based on Sentinel‐2 (Sentinel‐3) imagery achieved R2 scores of 0.47 (0.42) for chlorophyll‐a, 0.69 (0.22) for phycocyanin, and 0.70 (0.41) for Pc:Chla. Dissolved oxygen models achieved an R2 of 0.68 (0.36) when applied to Sentinel‐2 (Sentinel‐3) imagery, and Pc:Chla is found to be the most important predictive feature. Random forest models are better suited to water quality estimations in this system given built in methods for feature selection and a relatively small data set. Use of these approaches for estimation of Pc:Chla and dissolved oxygen can increase the water quality information extracted from satellite imagery and improve characterization of algae conditions among inland waters.

Nanoplastics increase algal absorption and toxicity of Cd through alterations in cell wall structure and composition

Nanoplastics (NPs) may act as carriers of heavy metals and cause complex toxicity to aquatic organisms, while the exact role of NPs in the joint toxicity remains unclear. Here, we investigated the joint toxicity of polystyrene NPs (PS-NPs) and Cd to freshwater algae (Chlorella vulgaris). It was found that PS-NPs (1 mg L−1) could hardly enter algal cells and slightly inhibit algal growth (p < 0.01). The effect of PS-NPs as carriers on the joint toxicity of PS-NPs and heavy metals could be neglected because of the limited adsorption of Cd by PS-NPs, while the PS-NPs altered the cell wall structure and composition, which resulted in the increased algal absorption and toxicity of Cd. Compared to the low dose Cd (0.4 mg L−1) treatment alone, the extracellular and intracellular Cd contents in the cotreatment were significantly increased by 27.3 % and 18.0 %, respectively, due to the increased contents of cell wall polysaccharides (pectin and hemicellulose in particular) by the PS-NPs. Furthermore, after the high dose Cd (2 mg L−1) exposure, the inhibited polysaccharide biosynthesis and the loosen cell wall structure weakened the tolerance of cell wall to abiotic stress, facilitating the entry of PS-NPs into the algal cells and inducing the higher toxicity. These results elucidate the mechanism by which NPs enhance heavy metal toxicity to algae, providing a novel insight into environmental risks of NPs.

A comprehensive review of water quality control on lentic ecosystem through the water quality, IoT and aeration models

Eutrophication is the term used to describe the phenomenon in which a body of water becomes excessively loaded with nutrients, leading to a population of basic plant life. Excessive growth of algae and planktonic organism’s manifests as blooms on the water surface. Eutrophication gets worse in a lentic ecosystem when there is no outflow or water movement, resulting in the accumulation of pollutants on the surface. Water quality measurements, including temperature, pH, dissolved oxygen (DO), and biochemical oxygen demand (BOD), exhibit correlations with one another. Therefore, this article provides a comprehensive review of the water quality model, aeration system, and IoT technology. The water quality model enables the development of forecasts on future water quality. Therefore, effective water quality management can be strategized based on the specific attributes of the water. In addition, an aeration system is a technology used to improve water quality by enhancing oxygen levels and decreasing nutrient levels. Furthermore, it has been shown that real-time surveillance with IoT technology can enhance precision, effectiveness, and reduce time consumption. Therefore, it is important to priorities the implementation of water quality model, aeration, and IoT technology since they offer significant benefits in controlling water quality.

Repeated Exposure Enhanced Toxicity of Clarithromycin on Microcystis aeruginosa Versus Single Exposure through Photosynthesis, Oxidative Stress, and Energy Metabolism Shift.

Antibiotics are being increasingly detected in aquatic environments, and their potential ecological risk is of great concern. However, most antibiotic toxicity studies involve single-exposure experiments. Herein, we studied the effects and mechanisms of repeated versus single clarithromycin (CLA) exposure on Microcystis aeruginosa. The 96 h effective concentration of CLA was 13.37 μg/L upon single exposure but it reduced to 6.90 μg/L upon repeated exposure. Single-exposure CLA inhibited algal photosynthesis by disrupting energy absorption, dissipation and trapping, reaction center activation, and electron transport, thereby inducing oxidative stress and ultrastructural damage. In addition, CLA upregulated glycolysis, pyruvate metabolism, and the tricarboxylic acid cycle. Repeated exposure caused stronger inhibition of algal growth via altering photosynthetic pigments, reaction center subunits biosynthesis, and electron transport, thereby inducing more substantial oxidative damage. Furthermore, repeated exposure reduced carbohydrate utilization by blocking the pentose phosphate pathway, consequently altering the characteristics of extracellular polymeric substances and eventually impairing the defense mechanisms of M. aeruginosa. Risk quotients calculated from repeated exposure were higher than 1, indicating significant ecological risks. This study elucidated the strong influence of repeated antibiotic exposure on algae, providing new insight into antibiotic risk assessment.

The impact of temperature variation on the algae–zooplankton dynamics with size-selective disturbance

The phenomenon of algal blooms caused by global warming frequently occurs in global water bodies, however, the mechanism by which temperature affects algal growth is still unclear. In this paper, we investigate the dynamics of a deterministic algae–zooplankton model with water temperature, as well as its corresponding stochastic version. Mathematical theoretical work mainly analyzes the stability, persistence and Hopf bifurcation of the deterministic model, and performs a survival analysis on the stochastic model and shows the existence of a unique ergodic stationary distribution, which in turn provides a theoretical basis for numerical simulations. Numerical analysis indicates that the variation of temperature can generate complex impacts on the fundamental mechanisms underlying the growth of algae, whether in deterministic or stochastic environment. One of the most interesting results indicates that the decrease of temperature can destabilize the algae–zooplankton interactions, but increase their permanence; the increase of temperature can stabilize the algae–zooplankton interactions, but reduce their permanence.

Synthesis and characterization of surface-modified magnetic mesoporous silicate materials for phosphate adsorption.

The magnetic mesoporous silica material, Mag-MCM-41, was synthesized by coating magnetite (Fe3O4) nanoparticles with a mesoporous material called MCM-41. Mag-MCM-41 and modified nanomaterials Mag-MCM-41-NN and Mag-MCM-41-NN-Fe+3 which were modified with aminopropyl functional groups. In water and wastewater, phosphate anions are considered significant contaminants due to their detrimental impact on the environment. They promote the growth of algae, leading to eutrophication. The purpose of this study is to investigate the removal of phosphate anions from aqueous solutions using modified magnetic silica particles. The Mag-MCM-41 material exhibits hexagonal properties and belongs to the class of "mesoporous" materials. It has a surface area of 923 m2.g-1, which was determined through N2 adsorption-desorption isotherms, FTIR, TEM, BET, and SAXS analysis. Kinetic and adsorption isotherm studies were conducted using Mag-MCM-41, Mag-MCM-41-NN, and Mag-MCM-41-NN-Fe+3 adsorbents to examine the behavior of phosphate anions. The kinetic and adsorption isotherm studies of phosphate anions revealed that the adsorption process on Mag-MCM-41, Mag-MCM-41-NN, and Mag-MCM-41-NN-Fe+3 adsorbents followed the chemical adsorption mechanism. Phosphate adsorption on all adsorbents occurred in a monolayer, and the MCM-41-NN-Fe+3 adsorbent exhibited the highest maximum adsorption capacity (qm) value of 112.87 mg.g-1 compared to the other adsorbents.

Enhanced carotenoid production, biodiesel quality, and harvesting efficiency in microalga Graesiella emersonii via heterotrophic cultivation strategy

The aim of this study was to evaluate the potential industrial applicability of the green microalga Graesiella emersonii GEGS21 by comparing its biomass, photosynthetic pigments, and biodiesel properties under photoautotrophic (PA) and heterotrophic (HT) cultivation. Four agricultural soluble fertilizers (SFs) were tested as substitute medium for algal growth. Of these, three were not only cost-effective but also more efficient in promoting growth compared to the BG-11 algal medium. Supplementing the SF medium with 12 g/L of glucose significantly improved algal biomass productivity under HT condition, and the optimal conditions were identified as 0 M NaCl, a temperature of 30 °C, and a pH of 8. Subsequent supplementation with yeast extract led to a notable enhancement in algal growth, resulting in approximately 18.6-times higher biomass productivity compared to the PA condition. Under HT cultivation, the productivities of the photosynthetic pigments including lutein and zeaxanthin were significantly increased approximately by 3.6-fold and 3.5-fold, respectively compared to the PA condition (p < 0.05). Moreover, HT cultivation led to improved biodiesel properties, such as iodine value, cetane number, oxidative stability, and kinematic viscosity. These enhancements, achieved through altered fatty acid methyl ester composition, align with the ASTM D6751 and EN14214 biodiesel standards. Interestingly, when cultivated under HT conditions, algal strain exhibited higher sedimentation efficiency, accompanied by an enhanced cellular starch content, compared to both PA and mixotrophic conditions. This suggests a promising strategy for economically viable harvesting by altering the specific gravity of algal cells. In conclusion, our findings suggest that HT cultivation of Graesiella emersonii GEGS21 may serve as an effective approach to produce value-added compounds and bioenergy, offering potential for economical harvesting.

Microalgae cultivation in a biogas plant: Environmental and economic assessment through a life cycle approach

Using liquid digestate and flue gases from a microalgae cultivation in a biogas plant, enables nutrient and carbon uptake reducing the costs for nutrients for microalgae cultivation and reducing problems associated with the overproduction of digestate. The present study aims to examine the environmental impacts and economic aspects of a novel technology for microalgal cultivation. In particular, a combined LCA and LCC from a novel microalgae cultivation pilot system coupled with an operating biogas plant is proposed. The technological concept investigated aims to evaluate the potential benefits and drawbacks of the use of digestate and CHP flue gases from biogas a plant to sustain algal growth. Two scenarios were compared: i) a business-as-usual (i.e. baseline scenario) defined as a traditional biogas plant without microalgae cultivation, ii) a scenario with a scaled-up microalgae cultivation technology (Scenario 2) to highlight differences and evaluate the overall environmental and economic feasibility of a commercial scale. The comparison showed that the baseline scenario is slightly more advantageous in environmental performances than that associated with microalgae cultivation.The techno-economic assessment shows an economic feasibility with a positive NPV value (i.e. 2 573 935 €) and good IRR (i.e. 14). The implementation of Scenario 2 with microalgae cultivation is found primarily in its relatively low operational costs as the thermal and electrical energy, digestate, and CO2 required for operation and algal growth come from the associated biogas plant. However, technical improvements should be considered to reduce the capital costs associated with the construction of microalgae cultivation plant.

Climate Change Impacts on Water Temperatures in Urban Lakes: Implications for the Growth of Blue Green Algae in Fairy Lake

Cyanobacteria, also known as blue-green algae, are photosynthetic bacteria that play a crucial role in aquatic ecosystems and are susceptible to changes in temperature. Hence, as global temperatures rise due to climate change, some Cyanobacterial species will thrive in warmer temperatures, which will result in increased blooms during the growing season. The MIKE-3 model is calibrated to existing (2022) conditions and is used to assess the impact of the RCP 4.5 scenario for the year 2050 in Fairy Lake (a shallow urban lake in Ontario). The simulations projected indicate that in 2050, in the central parts of Fairy Lake’s central basin, water temperatures will be above 20 °C for 2281 h compared to 2060 h in 2022. This situation indicates there will be a 10.7% increase in the duration of Cyanobacteria blooms in the central area of Fairy Lake. Similarly, in the northern area of Fairy Lake, the MIKE-3 model results indicate that surface temperature durations above 20 °C will increase from 1628 h to 2275 h for the year 2050, resulting in an additional 647 h of increased temperatures at the surface under RCP 4.5 scenario conditions. This situation indicates there will be a 39.7% increase in the duration of Cyanobacteria blooms in the northern portion of Fairy Lake. These modeling conditions indicate there will be significantly more habitat amenable to Cyanobacteria growth when surface water temperatures are above 20 °C, indicating substantial increases in the available growth time of Cyanobacteria due to climate change, all of which translate to major concerns caused by climate change.

Toxic effects and action mechanism of metal-organic framework UiO-66-NH2 in Microcystisaeruginosa

The zirconium metal-organic framework UiO-66-NH2 has garnered considerable attention for their potentials of removing environmental contaminants from water. The production and application of UiO-66-NH2 make their releases into the aquatic environment inevitable. Nevertheless, little information is available regarding its potential risk to the environment and aquatic organisms, thus limiting the evaluation of its safe and sustainable use. In this study, the ecotoxicity of UiO-66-NH2 was evaluated, specifically its impacts on growth, extracellular organic matter release, and metabolomic changes of the model phytoplankton Microcystis aeruginosa (M. aeruginosa). UiO-66-NH2 exhibited moderate effects on algal physiology including growth, viability, and photosynthetic system. At concentrations below 20 mg/L, UiO-66-NH2 induced negligible inhibition of algal growth, algal viability, and photosynthesis. In contrast, UiO-66-NH2 boosted the release of extracellular organic matter even at concentration as low as 0.02 mg/L. These findings indicated that, while no evident damage to algal cells was observed, UiO-66-NH2 was hazardous to the aquatic environment as it stimulated the release of algal toxins. Moreover, UiO-66-NH2 entered algal cells rather than adhering to the surface of M. aeruginosa as observed by the fluorescence imaging. Based on metabolic analysis, UiO-66-NH2 influenced the cyanobacteria mainly through interference with purine metabolism and ABC transporter. This study sheds light on the potential threat UiO-66-NH2 posing to microalgae, and has potential implications for its safe utilization in the environmental field.

Ionic and nanoparticulate silver alleviate the toxicity of inorganic mercury in marine microalga Chaetoceros muelleri.

Toxicological effects of silver nanoparticles (SNPs) in different organisms have been studied; however, interactions of SNPs with other environmental pollutants such as mercury are poorly understood. Herein, bioassay tests were performed according to ΟECD 201 guideline to assess the toxic effects induced by mercury ions (mercury chloride, MCl) on the marine microalga Chaetoceros muelleri in the presence of SNPs or silver ions (silver nitrate, SN). Acute toxicity tests displayed that the presence of SNPs or SN (0.01mg L-1) significantly reduced the toxicity of MCl (0.001, 0.01, 0.1, 1, 10, and 100mg L-1) and increased the IC50 of MCl from 0.072 ± 0.014 to 0.381 ± 0.029 and 0.676 ± 0.034mg L-1, respectively. In the presence of SN or SNPs, the mercury-reducing effect on algal population growth significantly decreased. Considering the increase of IC50, the mercury toxicity decreased approximately 5.44 and 9.66 times in the presence of SNPs or SN, respectively. The chlorophyll a and c contents decreased at all exposures; however, the decrease by MCl-SNPs and MCl-SN was significantly less than MCl except at 1mg L-1. The lowering effect of MCl-SN on chlorophyll contents was less than MCl and MCl-SNPs. MCl exposure induced significant raises in total protein content (TPC) at concentrations < 0.01mg L-1, with a maximum of ~ 70.83% attained at 100mg L-1. The effects of MCl-SNPs and MCl-SN on TPC were significantly less than MCl. Total lipid content (TLC) at all MCl concentrations was higher than the control, while at coexposure to MCl-SN, TLC did not change until 0.01mg L-1 compared with the control. The effects of MCl-SN and MCL-SNPs on TPC and TLC were in line with toxicity results, and were significantly less than those of MCl individually, confirming their antagonistic effects on MCl. The morphological changes of algal cells and mercury content of the cell wall at MCl-SN and MCl-SNPs were mitigated compared with MCl exposure. These findings highlight the mitigatory impacts of silver species on mercury toxicity, emphasizing the need for better realizing the mixture toxicity effects of pollutants in the water ecosystem.

Effect of pH and Light Intensity on the Growth of Dunaliella Salina

&#x0D; &#x0D; &#x0D; Dunaliella salina is a unicellular halophilic green alga dominantly found in salt lakes, and high saline ponds in slatterns all over the world. A rigid cell wall is absent in D. salina while the cells are covered by mucous materials that are enclosed by a thin elastic plasma membrane. This species has both environmental and economic validity as they are capable of producing β–carotene during photosynthesis. Synthesis of β–carotene in D. salina is a function of environmental factors, and thus, the present study was designed to study the effect of pH of the medium and light intensity on the growth of D. salina. The Algae sample was collected from a crystalizing pond of Hambantota Saltern, Sri Lanka, and a monoculture was maintained under suitable laboratory conditions. The seawater sample with pH 7.66 was used to prepare a series of pH using sodium carbonate anhydrous. These cultures were exposed to a series of pH (7.66, 8.0, 8.50, and 9.0) at two light intensities (885 lux and 200 lux). All experimental setups were maintained at 25oC with the photoperiod of 12h light and 12h dark. Four replicates of each pH medium were arranged into a 4×4 setup of flasks for each light intensity and the experiment was conducted for four weeks. At the end of the fourth week, the pH level of all flasks ranged from 8.27 to 8.53 due to the self-adjustment of the pH level in the culture medium in parallel to algal growth. The maximum growth was reflected by the highest absorbance of 1.46 at 750 nm. Taken together, our findings revealed that the optimum pH range and light intensity for culturing D. salina is 8.27-8.53 and 885 lux respectively. This study recommends further research on culturing of D. salina for extracting the bioproduct of β -carotene at various light intensity levels.&#x0D; Keywords: Cell density, β –carotene, Light intensity, Self-adjusted&#x0D; &#x0D; &#x0D;

PHYSICO-CHEMICAL PARAMETERS AND CLIMATE CHANGE IMPACT ON ALGAL GROWTH

Identifying the biological processes that influence algal growth is essential for ecosystem management. Algae are little aquatic plants that exist either as solitary cells or in regions of diverse dimensions. Zooplankton rely on them as a crucial component of the aquatic food chain, since they provide as their primary source of nutrition. Algae, via the process of photosynthesis, produce oxygen that is subsequently released into the water, serving as a vital resource for fish and other aquatic organisms. This work presents a methodology for estimating the biological characteristics of algae, which play a crucial role in the regulation of eutrophication, via the use of modelling and exploration methodologies. The estimation of algae growth and respiration rates was conducted by using a one-dimensional water quality model and two-dimensional regionally distributed water quality data taken from Lower Manair Dam of Karimnagar District, Telangana. A total of 24 algae were detected in the sample. The most abundant types of algae include Green algae, Flagellate algae, Cyanobacteria, and Diatoms. In the summer season, 17 types of algae were found, while in the spring season, 20 types were detected. The estimation of biological characteristics of algae in natural freshwater environments may be achieved by a physico-chemical technique, which offers an alternate option to sampling and in situ testing. KEYWORDS: Algal growth, biological parameters, Lower Manair Dam, eutrophication, in situ testing

Long-term performance and degradation analysis of a 5 MW solar PV plant in the Andaman & Nicobar Islands

Renewable energy is being advocated as a new strategy in response to rising energy demand and global climate change. Solar photovoltaic technology is of great significance to climatic conditions due to the good solar intensity and availability to generate energy. In this paper, the 10-year operating performance of a 5 MW solar PV plant installed in tropical climate of the Andaman and Nicobar Islands was analysed. In 2015, the PV plant achieved its highest electricity production of 7216 MWh, while its lowest, 4757 MWh, was observed in 2022.The maximum performance ratio was recorded as 84.28 % in 2016 due to lower operating cell temperature whereas the maximum CUF as 16.17 % was recorded in 2015. The highest module, inverter and system efficiency for the ten year was observed 12.03 %, 97.64 % and 11.75 % respectively in year 2016. In 2014, the highest values for reference yield, array yield, and final yield were recorded as 4.92, 4.08, and 3.98 kWh/kW/day, respectively. Higher capture losses were observed in the plant over the year which varies upto 1.65 h/d. The plant exhibited a degradation rate of 1.99 % per annum, determined by employing an initial PR of 80.03 %, which declined to 64.11 % by 2022. Degradation analysis of the present system was also performed using visual inspection technique. Mostly found defects in plant was corrosion, delamination of encapsulant material, browning of cell material, burn mark on the back of module, milky patterns, cracks in top facing glass and solar cells. Since, the plant is located in the coastal area, it was seen that the plant is facing a severe issue of algae growth. Some PV modules were covered by more than 90 % algae which significantly contribute in capture losses.

Uptake and cellular responses of Microcystis aeruginosa to PFOS in various environmental conditions

Although PFOS has been banned as a persistent organic pollutant, it still exists in large quantities within the environment, thus impacting the health of aquatic ecosystems. Previous studies focused solely on high PFOS concentrations, disregarding the connection with environmental factors. To gain a more comprehensive understanding of the PFOS effects on aquatic ecosystems amidst changing environmental conditions, this study investigated the cellular responses of Microcystis aeruginosa to varying PFOS concentrations under heatwave and nutrient stress conditions. The results showed that PFOS concentrations exceeding 5.0 µg/L had obvious effects on multiple physiological responses of M. aeruginosa, resulting in the suppression of algal cell growth and the induction of oxidative damage. However, PFOS concentration at levels below 20.0 µg/L has been found to enhance the growth of algal cells and trigger significant oxidative damage under heatwave conditions. Heatwave conditions could enhance the uptake of PFOS in algal cells, potentially leading to heightened algal growth when PFOS concentration was equal to or less than 5.0 µg/L. Conversely, deficiency or limitation of nitrogen and phosphorus significantly decreased algal abundance and chlorophyll content, inducing severe oxidative stress that could be mitigated by exposure to PFOS. This study holds significance in managing the impact of PFOS on algal growth across diverse environmental conditions.

Comparative assessment of oestradiol removal in Scenedesmus-Rhodococcus and Microcystis-Raoultella symbiotic systems versus monoculture systems

ABSTRACT In this study, the abilities two kinds of algae, Scenedesmus and Microcystis aeruginosa, and two kinds of bacteria, Rhodococcus and Raoultella planticola, to remove oestradiol when in a symbiotic system were investigated. The effects of the combined systems as well as the effects of each bacterium and algae alone were examined. We then compared the improvements from the bacteria-algae symbiosis systems with Microcystis aeruginosa and Raoultella planticola. The results showed that the oestradiol removal rate of the best system was 97.6%, while that from the Microcystis aeruginosa and Raoultella planticola system was 89%. HIGHLIGHTS Oestradiol has an effect on algal growth. The effects of algae on the growth of degrading bacteria were investigated. Degrading bacteria can affect the growth of algae. The symbiosis of bacteria and algae effectively removed oestradiol, with a removal rate that reached 97.6%.

Characteristics of dissolved organic matter during the cyanobacterial degradation in Chaohu Lake, China.

The actual DOM in Chaohu Lake was used to feed cyanobacterial to explore the changes of microbial communities, fluorescence spectral characteristics and molecular composition of DOM during the degradation of cyanobacteria. It is found that cyanobacterial grow periodically depending on the concentration of nutrients with the decreasing concentration of nutrient salts. Both Bacteroidetes and Actinobacteria have strong correlation with algae growth. Bacteroidetes has a positive correlation with algae growth, relationship on the contrary, Actinobacteria has a negative relationship. The humus-like components in the four groups are similar, but the protein-like component (C3) shows periodic changes with the life process of cyanobacteria. The average molecular weight of each sample detected by Orbitrap high-resolution mass spectrometer increases slightly and the DOM increase aromaticity in the end. In this study, the molecule of Carboxyl-Rich Alicyclic Molecules (CRAM) is difficult to be done by photodegradation and biodegradation in the early periods, but some molecules of CRAM are selectively degraded by microorganisms in the final period. The growth of cyanobacterial lead to increasing the concentration of protein-like and carbohydrate-like molecule of DOM in the water. In the final stage, the molecule group of CHO disappear significantly and the molecule group of heteroatomic group increase.

Boosting wastewater treatment and CO2 bioremediation with Nile River microalgae: Resilience to simulated smoke and enhanced biomass production

This study investigated the potential of Nile River microalgae for treating wastewater under simulated air pollution conditions. We evaluated microalgal growth and nutrient removal efficiency in wastewater with and without microalgal inoculation. Results demonstrated enhanced algal growth rates in all wastewater samples, with maximum chlorophyll (a) concentrations reaching 3093.2 μg/L and 4157.4 μg/L, respectively. This suggests efficient utilization of organic pollutants, with nutrient removal exceeding 90 % efficiency. Notably, Scenedesmus sp. emerged as the most resilient species, achieving the highest biomass production (735.5 mg/L) at a moderate CO2 concentration (16.6 mg/L). Interestingly, optimal CO2 concentrations enhanced the highest growth rate by 0.84 day−1, demonstrating the potential for simultaneous wastewater treatment and CO2 bioremediation. These findings highlight the promise of Nile River microalgae, particularly Scenedesmus sp., for sustainable wastewater treatment even in polluted environments, offering a dual benefit of environmental remediation and bioresource production.

Testing the effect of semi-transparent spectrally selective thin film photovoltaics for agrivoltaic application: A multi-experimental and multi-specific approach

The integration of photovoltaic technologies within the agricultural framework, known as agrivoltaics, emerges as a promising and sustainable solution to meet the growing global demands for energy and food production. This innovative technology enables the simultaneous utilization of sunlight for both photovoltaics (PV) and photosynthesis. A key challenge in agrivoltaic research involves identifying technologies applicable to a wide range of plant species and diverse geographic regions. To address this challenge, we adopt a multi-experimental and multi-species approach to assess the viability of semi-transparent, spectrally selective thin-film silicon PV technology. Our findings demonstrate compatibility with crop production in controlled environments for both plants and algae. Notably, selective thin-film PV exhibits the potential to enhance crop yields and serves as a photo-protectant. We observe that plant and algal growth increases beneath the selective PV film when supplemented with appropriate diffuse light in the growth environment. Conversely, in situations where light intensity exceeds optimal levels for plant growth, the selective PV film provides a photo-protective effect. These results suggest potential supplementary benefits of employing this technology in regions characterized by excessive light irradiation, where it can contribute to healthy plant growth.

Toxic Effects of Copper Oxide Nanoparticles on Chlorella vulgaris

Abstract Aim: Exploitation of nano-based materials has increased the disposal of nanoparticles into the environment. Toxic nanomaterials pose their adverse effects and severely impact the human and environmental health. The aim of this study was to explore the toxic effects of chemically-synthesized copper oxide nanoparticles (CuO-NPs) on Chlorella vulgaris using an algal growth inhibition assay. Materials and Methods: Nanoparticles were synthesized using cupric sulfate and sodium hydroxide. Synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy. C. vulgaris culture was exposed to various concentrations of CuO-NPs at intervals of 3, 6, 12, and 24 h. Growth inhibition assay of algal culture was estimated via the spectroscopic method and cell enumeration was done by Neubauer hemocytometry. Results: The average diameter of CuO-NPs was ~35.85 nm. UV-Vis spectroscopy was used to confirm the configuration of CuO-NPs. Therefore, FTIR results has indicated high purity of synthesized CuO-NPs. Size of the CuO-NPs was determined by XRD. Results showed that growth of C. vulgaris microalgae was notably affected by the exposure of 2 mg/L CuO-NPs concentration exposure for 6 h. Conclusion: The current work showed that CuO-NPs have significant toxic to Chlorella sp. Data analysis showed NPs have broad effects on growth of C. vulgaris and there is a correlation between nanoparticles concentration as well as their toxicity on the microalgae.