Water Algae Research Articles

Advanced electrochemical strategies for simultaneous removal of Microcystis aeruginosa and microcystin-LR: On-demand optimization and mechanistic insights

The frequent occurrence of harmful cyanobacterial blooms and toxins poses significant threats to aquatic life and drinking water safety. This work reports the removal mechanisms of M. aeruginosa and microcystin-LR (MC-LR) using the Pt-Graphite felt (GF) electrochemical system, which builds upon prior research to investigate diverse processes driven by distinct mechanisms within a single reactor, primarily by pH regulation. Factors affecting removal were assessed through single-factor trials and Box-Behnken design, identifying optimal conditions for successful algae removal, finally a 96% removal efficiency of algae cells and an 83% elimination efficiency of MC-LR within a 60-minute timeframe. Particularly at non-optimal pH 7 conditions, the Pt-GF system showcases synergistic effects, enhancing electro-flocculation and weakening electro-Fenton reactions. Conversely, at an optimal pH of 3, the electro-Fenton process is favorably enhanced, leading to improved removal efficiency through escalated reactive oxygen species generation. Additionally, the system exhibits consistent repeatability in its performance. Notably, its effectiveness is substantiated across varying nitrogen and phosphorus levels and in simulated water samples containing multiple algal species. In essence, this subtly adaptable reactor tuning integrates electro-Fenton, electro-flocculation, electro-adsorption, and electrochemical direct oxidation effects for the first time, potentially providing a more effective and manageable solution for addressing harmful algae in water.

Effects of Irrigation with Slightly Algae-Contaminated Water on Soil Moisture, Nutrient Redistribution, and Microbial Community

The presence of excessive algae in water is always considered as a negative factor in irrigation. However, the optimal balance between algal removal and retention in irrigation water when the algal biomass is controllable remains unknown. Therefore, this study explores the impact of low-level algal presence (Scytonema javanicum) on soil and microbial activity through controlled soil column experiments. Soil moisture was measured, and 16S rRNA gene amplicons sequencing was applied to characterize the microbial community. Slight community changes indicated no negative impact on the local microbial community of S. javanicum. Enzyme assays and quantitative polymerase chain reaction (qPCR) revealed that algae improved soil moisture retention, and enhanced the nutrient content of the topsoil. The decrease in moisture in the treatment group (from 27.53% to 26.42%) was significantly reduced (p < 0.05) compared to the control (from 27.55% to 25.17%), while the contents of ammonium (NH3-N) and total nitrogen (TN) in the treatment (0.70 mg/kg and 0.54 g/kg) were also higher (p < 0.05) than that of the control (0.43 mg/kg and 0.49 g/kg). The results of the abundance of functional gene suggested algae facilitated nitrogen fixation and nitrification. This research offers innovative insights for diversifying the sources of irrigation water.

The Effect of Salinity Stress on the Antibacterial Activity of SpirulinaPlatensis Algae

Background: The production of secondary metabolites in different strains of microalgae varies and is likely dependent on environmental conditions. Consequently, the production of bioactive substances as secondary metabolites occurs in microalgae to aid their survival in adverse environmental conditions such as salinity stress. Objectives: The purpose of this study is to investigate the antibacterial activity of the methanolic extract of S. platensis algae cultivated under different salinity stresses against Yersinia rukeri, Escherichia coli, Salmonella sp., and Vibrio cholerae. Methods: The broth microdilution method was used to evaluate the growth inhibitory activity of the extracts against Yersinia ruckeri, Salmonella sp., Escherichia coli, and Vibrio cholerae bacteria. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined by this method, and the diameter of the inhibition zone was assessed through the well diffusion method. Results: In the treatment with algae extract grown under 3.5 ppt salinity stress, the concentrations of 50 and 25 mg/mL extract showed the largest inhibition zone diameter against Salmonella sp. compared to other bacteria. Under 7 ppt salinity stress, all studied concentrations of algal extract exhibited a higher inhibition zone diameter against V. cholerae compared to other bacteria. The results of comparing different concentrations of algae extract between the two salinity stresses of 3.5 and 7 ppt for each bacterium showed a significant difference (P < 0.05). As salinity increased, the diameter of the inhibition zone also increased for all bacteria. Conclusions: Our results showed an increase in the antibacterial activity of the methanolic extract of Spirulina platensis with higher salinity stress levels. Therefore, cultivating Spirulina algae in salt water can be a cost-effective and suitable method to produce more secondary metabolites for use in the pharmaceutical industry.

Photosynthetic processes in Antarctic sea ice during the spring melt

AbstractHigh‐latitude oceans experience strong seasonality where low light limits photosynthetic activity most of the year. This limitation is pronounced for algae within and underlying sea ice, and these algae are uniquely acclimated to low light levels. During spring melt, however, light intensity and daylength increase drastically, triggering blooms of ice algae that play important roles in carbon cycling and ecosystem productivity. How the algae acclimate to this dynamic and heterogeneous environment is poorly understood. Here, we measured 14C‐carbon fixation rates, photophysiology, and ribulose 1,5‐bisphosphate carboxylase oxygenase (Rubisco) content of sea‐ice algae in coastal waters near the western Antarctic Peninsula during spring, ranging from a low‐light‐acclimated, bottom community to a light‐saturated bloom. Carbon fixation rates by sea‐ice algae were similar to other Antarctic sea‐ice measurements (2–49 mg C m−2 d−1), and there was little phytoplankton biomass in the underlying water at the time of sampling. Net‐to‐gross ratios of carbon fixation were generally high and showed no relationship with ice type. We found algal photophysiology and Rubisco concentrations varied in relation to the different types of ice, altering the balance between the photochemical and biochemical processes that constrain carbon fixation rates. For algae inhabiting the bottom layers of sea ice, rates of carbon fixation were largely constrained by light availability whereas in surface seawater, interior and rotten/brash ice, carbon fixation rates could be calculated with reasonable accuracy from measurements of Rubisco concentrations. This work provides additional insight and means to evaluate carbon fixation rates as sea ice continues to change in future.

Toxic mechanisms of the antiviral drug arbidol on microalgae in algal bloom water at transcriptomic level

Increasing antivirals in surface water caused by their excessive consumption pose serious threats to aquatic organisms. Our recent research found that the input of antiviral drug arbidol to algal bloom water can induce acute toxicity to the growth and metabolism of Microcystis aeruginosa, resulting in growth inhibition, as well as decrease in chlorophyll and ATP contents. However, the toxic mechanisms involved remained obscure, which were further investigated through transcriptomic analysis in this study. The results indicated that 885–1248 genes in algae were differentially expressed after exposure to 0.01–10.0 mg/L of arbidol, with the majority being down-regulated. Analysis of commonly down-regulated genes found that the cellular response to oxidative stress and damaged DNA bonding were affected, implying that the stress defense system and DNA repair function of algae might be damaged. The down-regulation of genes in porphyrin metabolism, photosynthesis, carbon fixation, glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation might inhibit chlorophyll synthesis, photosynthesis, and ATP supply, thereby hindering the growth and metabolism of algae. Moreover, the down-regulation of genes related to nucleotide metabolism and DNA replication might influence the reproduction of algae. These findings provided effective strategies to elucidate toxic mechanisms of contaminants on algae in algal bloom water.

Development of Multifunctional Tablet Formulation for Use In Swimming Pools

The pool waters pose certain risks to public health. Therefore, it is crucial for swimming pool water to meet the desired standards in terms of physical, chemical, and biological parameters, and to be regularly monitored to ensure the provision of healthy and safe swimming conditions. In our country, swimming pool water standards are determined in accordance with regulations set forth by the Ministry of Health. To maintain these standards, various pool chemicals are required, including pool water disinfectants, pH reducers, precipitators, brighteners, and algae inhibitors. The objective of our study is to develop a multifunctional tablet formulation, a technological innovation that combines the properties of these chemicals into a single product. To achieve this goal, we conducted physical and bactericidal tests on new formulations containing disinfectants such as calcium hypochlorite, trichloroisocyanuric acid, and sodium dichloroisocyanurate. The multifunctional tablet formulations developed provide an effective solution to meet and exceed the required standards for swimming pool water quality.

Potential Benefits of a Cosmetic Ingredient Combining Thermal Spring Water and Diatom Algae Extract

The development of cosmetic ingredients improving the management of skin with irritation proclivity is an actual need. However, medical recommendations in specific cases, such as sensitive skin, include the use of as few and low-reactive ingredients as possible. In this context, we here describe the development of a new ingredient consisting of a mixture of thermal water and a diatom algae extract. First, we characterized a thermal spring water (La Solia, LS-TSW). Attending to its chemical composition, LS-TSW displayed an exclusive combination of different inorganic elements, with interesting potential properties when compared with other commercial spring waters. Then, LS-TSW hydrobiome was studied, and after finding specimens of Phaeodactylum-like sp., we proposed potentiating LS-TSW benefits with its combination with an oil extract of Phaeodactylum tricornutum (PtOE). Finally, we assessed the potential of the mixture during pro-inflammatory stimulation, in the first instance using an immune cell model, and then in an in vitro system mimicking keratinocytes under skin irritation. In the last-mentioned model, the ingredient of interest effectively attenuated the induced levels of different pro-inflammatory mediators (IL-6, IL-1, TNFα, NF-κB, and CCL1), at the level of gene expression. Thus, our results highlight the potential benefits of this combination in the context of skin irritation, opening roads for its use in new skincare regimens, and addressing an important dermatological concern.

Distribution patterns and co-occurrence network of eukaryotic algae in different salinity waters of Yuncheng Salt Lake, China

The community structure and co-occurrence pattern of eukaryotic algae in Yuncheng Salt Lake were analyzed based on marker gene analysis of the 18S rRNA V4 region to understand the species composition and their synergistic adaptations to the environmental factors in different salinity waters. The results showed indicated that the overall algal composition of Yuncheng Salt Lake showed a Chlorophyta-Pyrrophyta-Bacillariophyta type structure. Chlorophyta showed an absolute advantage in all salinity waters. In addition, Cryptophyta dominated in the least saline waters; Pyrrophyta and Bacillariophyta were the dominant phyla in the waters with salinity ranging from 13.2 to 18%. Picochlorum, Nannochloris, Ulva, and Tetraselmis of Chlorophyta, Biecheleria and Oxyrrhis of Pyrrophyta, Halamphora, Psammothidium, and Navicula of Bacillariophyta, Guillardia and Rhodomonas of Cryptophyta were not observed in previous surveys of the Yuncheng Salt Lake, suggesting that the algae are undergoing a constant turnover as the water environment of the Salt Lake continues to change. The network diagram demonstrated that the algae were strongly influenced by salinity, NO3−, and pH, changes in these environmental factors would lead to changes in the algal community structure, thus affecting the stability of the network structure.

Mathematical model for the elimination of algae and cyanobacteria in eutrophic waters by using different oxidizing agents

Mathematical model for the elimination of algae and cyanobacteria in eutrophic waters by using different oxidizing agents

Elimination of Chlorella using peracetic acid activated by dielectric barrier discharge plasma: Mechanism and cell deactivation process

Excessive proliferation of algae in water depletes dissolved oxygen, resulting in the demise of aquatic life and environmental damage. This study delves into the effectiveness of the dielectric barrier discharge (DBD) plasma activated peracetic acid (PAA) system in deactivating Chlorella. Within 15 min, the algae removal effectiveness reached 89 % under ideal trial conditions. DBD plasma activation of PAA augmented the concentration of reactive species such as ·OH, 1O2, and organic radicals (RO·) in the solution, which are involved in the process of cell inactivation. Reactive oxygen species (ROS) within Chlorella cells continued to rise as a result of treatment-induced damage to the morphological structure and cell membrane of the organism. DNA and chlorophyll-a (Chl-a), were oxidized and destroyed by these invasive active compounds. This study presents an efficient advanced oxidation method to destroy algal cells and adds an alternative strategy for algal control in areas where eutrophication occurs.

Algae in Recreational Waters: An Overview within a One Health Perspective

Recreational water activities are widely recognized to have a positive impact on our physical and mental well-being. However, recreational water sources and their management are also a risk factor for human health due to different agents, including the overgrowth of cyanobacteria and algae. The presence of cyanobacteria and algae in recreational waters represents a One Health threat because of their potential release and the overuse of biocides. These organisms have the potential to metabolize organic matter and produce thermophilic and thermotolerant toxins. Moreover, different species of algae are involved in biofilm formation processes, thus impacting water quality and safety and also posing risks to the environment and animal and human health. Different species of algae participate in biofilm formation and have an impact on managing water and equipment maintenance. By searching literature databases, e.g., PubMed, we reviewed the state of the art, providing basic definitions, taxonomy, and epidemiological or medical issues related to the recreational uses of water. Methods of treatments and monitoring were summarized, considering both traditional and innovative strategies. Public health and surveillance approaches focus on the detection of toxins, the formation of biofilms, and the understanding of the benthonic and planktonic components as part of the larger microbial biodiversity. The review process allowed us to acknowledge that this is the first comprehensive overview of algae in recreational waters carried out within a wider One Health outlook.

The presence of harmful algae in the coastal waters of Bintan Island, Riau Islands

The presence of harmful algae in the coastal waters of Bintan Island, Riau Islands

Pengembangan Awal Alat Pemanen Alga Sistem Rotating Filtered-Drum Untuk Perbaikan Kualitas Air di Perairan Tergenang

The phenomenon of overgrowth of green algae and cyanobacteria indicates a serious aquatic environmental problem from eutrophication. In aquatic ecosystems, algae are an integral part of the ecological system. But when there is abundant algae growth in the waters it causes the phenomenon of harmful alga blooms. Algae that were previously invisible, due to clumping, this group becomes invisible to the eye. The follow-up impact of the algae blooms is fish death, due to lack of oxygen at night. Algal masses that are swept by the wind onto the shores of bays and reservoir shores cause buildup and decay. Among the efforts that can be made in dealing with the phenomenon of abundant algae in waters is harvesting. In this study, the technique of harvesting by filtration and centrifugal rotation in a drum was applied. The purpose of this study was to design and build a filtration system algae harvester with a Rotating Filtered-Drum type. The results of preliminary research on filtration of water contaminated with algae from the facultative pond of the Bojongsoang-Bandung WWTP by gravity showed that the T 165 filter was able to reduce TSS levels as an indicator of algae by 72.85%. The Rotating Filtered-Drum tool requires further research for operational trials using pool water contaminated with algae. Keywords: algal blooming, lentic waters, euthrophic, green algae, cyanobacteria.

Molecular identification and nutritional analysis of green tide algae in the coastal waters of Qinhuangdao, China

Since 2015, the coastal waters of Qinhuangdao in Hebei province, China have experienced green tide disasters for consecutive years. Resource utilization is an important measure for preventing and controlling green tides. To comprehensively utilize green tide algae, this study first identified theses green tide algae and then assessed their nutritional value. Based on analysis of the internal transcribed spacer (ITS), 5S spacer regions (5S) and the mitochondrial cytochrome C oxidase I (COI), the dominant species were Ulva prolifera, Bryopsis plumose, Ulva australis, and Gracilariopsis lemaneiformis. The basic nutritional components, i.e., chlorophyll, amino acids, mineral elements, and heavy metal contents, of these four algae were measured and analyzed, and the four dominant species were shown to be high-nutrient-value marine foods with complete and reasonable protein, amino acid, and mineral compositions. This indicates that there is value in further research and development towards their utilization as nutrient sources. This study provides a basis for the comprehensive development and utilization of green tide algae resources in the coastal waters of Qinhuangdao.

Algae biofilm induced surface erosion of acrylic coatings

A major factor influencing failures of water-based elastomeric roof coatings is extended exposure to ponding water, biofilm development, attachment, and damage. Development of improved coatings is slow due to outdoor exposure tests that can take years. The goal of this work is to develop accelerated test methods and to understand the mechanism of biofilm-induced damage of coatings. Two model acrylic coatings on TPO substrates were exposed to lab-controlled accelerated growth of biofilm (algae) in ponding water to learn about coating damage before and after subsequent wet-dry cycles. Three distinct damage features in sequence were observed: (1) pit formation on the coating surfaces, (2) the biofilm mud-cracking induced coating surface damage upon drying, and (3) erosion (surface cracks) of coating in the mud-cracked region over the wet-dry cycles. Drying of adequately bonded biofilm to the coating and the thickness of the biofilm are the critical factors that govern the erosion on the coating surfaces. The effect of the wet-dry cycle time period was studied with respect to the surface erosion of the coatings. The mechanisms of biofilm-induced erosion during wet-dry cycling are postulated based on the mechanics and experimental observations. A new accelerated testing methodology for evaluating long-term roof coating performance is proposed.

Determine the Essential Micronutrients Intake by Vibrio cholerae in Association with Algae in Different Waters

Phosphate, nitrite, nitrate are the micronutrients for Vibrio cholerae and algal growth. Current study intended to determine the utilization of these micronutrients by V. cholerae in association with algae in four different water (Distilled water, River water, Aritificial sea water and BOD dilution water). Amount of these micronutrients were estimated from stock water, control water and algal water by developing standard curve method. Among these four stock water, orthophosphate was the highest in amount (10.44µg/L) in BOD dilution stock water and significant positive changes (0.06 µg/L) from stock found in the algal water in River water microcosm. In stock sample , the highest amount of nitrite was found in both River and BOD dilution water (6.486µg/L) and the most significant increase ( 388.014µg/L) from stock was found in the control water of BOD dilution water. River stock water contained the maximum nitrate (1865.204µg/L) among four water types and the highest increase was found in the control water of River. In brief, the amount of phosphate, nitrite and nitrate varied with the types of water. Most cases amount of nitrite- nitrate increased by the decay of V. cholerae which used by algae for their growth and overloaded algae did not use phosphate from the surrounding water.

Removal of Microcystis aeruginosa by manganese activated sodium percarbonate: Performance and role of the in-situ formed MnO2

Previous studies have found that pre-oxidation of manganese salts such as potassium permanganate and potassium manganate can remove algae in water, while existing problems such as excessive oxidation and appearance of chromaticity. In this study, our objective was to induce a Fenton-like reaction by activating sodium percarbonate (SPC) with divalent manganese (Mn(II)) to pre-oxidize algae-contaminated water. The optimal dosage of Mn(II)/SPC was determined by assessing the zeta potential of the algae and the residual Mn(II) in the solution. Moreover, we conducted a characterization of the cells post-reaction and assessed the levels of dissolved organic carbon (DOC). The disinfection by-products (DBPs) (sodium hypochlorite disinfection)of the algae-containing water subsequent to Mn(II)/SPC treatment were measured. Experiments show that Mn(II)/SPC pre-oxidation at optimal dosage acquired 88% removal of algae and less damage to the cell membrane. Moreover, the Mn(II) acted not only as a catalyst but also formed MnO2 which adsorbed onto the cell surface and facilitated sedimentation. Furthermore, this technology exhibits the capability to effectively manage algal organic matters present in water, thereby mitigating the formation of nitrogen-containing DBPs. These results highlight the potential of Mn(II)/SPC treatment for treating water contaminated with algae, thus ensuring the safety and quality of water resources.

Application of magnesium and biosurfactant functionalized biochar composite in treating cyanobacteria in phosphorus and crude oil contaminated water

Various human activities have led to multiple contamination of natural water systems. The present study investigated the effect of a novel multifunctional biochar to treat nutrients, oil, and harmful algae in water. Specifically, magnesium (Mg) and biosurfactant rhamnolipid (RL) were incorporated into biochar, including Mg-biochar, RL-biochar, and Mg-RL-biochar. Their adsorption efficiency on phosphate and total petroleum hydrocarbons (TPH) was evaluated in separate batch studies. Also, the inhibition effect of RL-modified biochars on cyanobacteria was investigated. The results showed that Mg-impregnated biochar showed high adsorption capacity on phosphate (118 mg g−1), while RL-modified biochar significantly reduced TPH (especially aromatic and light aliphatic fraction) with adsorption capacity of 44.4 mg g−1. The inhibition effects of biochar composites on algae in water without contaminants were in order of Mg-RL-biochar > RL-biochar > biochar with biomass reduction ranging 61–64%. Overall, Mg-RL-biochar was suggested based on this study due to its ability to remove PO43− and TPH, and inhibit the growth of toxic algae.Graphical abstract

Taguchi Optimization on the Biooil Extraction from Fresh Water Algae (Spirogyra) Using Soxhlet Apparatus

The present investigation is aimed at maximizing the biooil yield (BOY) from the algal species Spirogyra by solvent extraction method with a nonpolar solvent n-hexane using a Soxhlet apparatus. Also, this present work is aimed at acquiring optimal physiochemical properties such as kinematic viscosity and iodine value of the biooil produced from the algae. To carry out this work, the Taguchi technique with the L9 orthogonal array (OA) was used. With the L9 OA, nine sets of experiments were directed as per the design matrix, and the results were analyzed using the Taguchi method with the help of Minitab 16 software. The results generated from this optimization process showcased that the BOY from the Spirogyra was found to be a maximum of 26.86% with the particle size (PS) being 0.462 μm, the response time (RT) of 60 minutes, the solvent ratio (SR) of 1 : 10, and the extraction temperature (ET) of 75°C. The optimal set of input parameters for the optimal output response kinematic viscosity of 1.92 mm2/s was found to be achieved with the PS being 0.462 μm, 60 minutes of RT, the SR of 1 : 15, and the ET of 75°C. Similarly, the optimal set of input parameters for the optimal output response iodine value was found to be at 0.322 μm PS, 120 minutes of RT, an SR of 1 : 5, and an ET of 75°C. The signal-to-noise ratio (SNR) for the output responses exposed that the PS exhibited a major impact on the BOY and kinematic viscosity and the contribution levels of 76.68 and 51.7%, respectively.

Toxic Algae in Inland Waters of the Conterminous United States—A Review and Synthesis

Cyanobacteria are the most common toxigenic algae in inland waters. Their toxins can affect the health of aquatic and terrestrial organisms, including humans. Other algal groups, such as haptophytes (e.g., Prymnesium parvum) and euglenoids (e.g., Euglena sanguinea), can also form harmful algal blooms (HABs) whose toxins cause injury to aquatic biota but currently have no known effects on human health. Prymnesium parvum, however, is responsible for some of the worst HAB-related ecological disasters recorded in inland waters. Here, we provide an overview of the primary toxigenic algae found in U.S. inland waters: cyanobacteria (planktonic forms), P. parvum, and E. sanguinea with the objective of describing their similarities and differences in the areas of HAB ecology, algal toxins, and the potential for future range expansion of HABs. A detailed account of bloom habitats and their known associations with land cover and use is provided from the perspective of water quality. This review revealed that salinity may have an influence on inland cyanobacterial blooms and cyanotoxins that had not been fully recognized previously.