Cyanobacterial Research Articles

IMPROVING THE ASSESSMENT OF THE ECOLOGICAL STATE OF SURFACE WATERS BY SATELLITE DATA

The article presents the results of research into the ecological state of surface waters using newly developed scientific approaches based on the use of high spatial resolution satellite data. The systematization of all available indicators and the development of new methodological approaches significantly improves the existing methodology for determining the ecological state of water bodies, which is the goal of research. In the studies of water bodies within the city of Kyiv, Obolon Bay and Lake Verbne, the optimal set of such indicators as spectral indices was determined, which made it possible to comprehensively assess the state of water bodies: NDWI - for distinguishing vegetation and water bodies, GCI - to assess the extent of blue-green algae, NDTI - to determine turbidity, IO - to determine the presence of soluble iron in water, NDSI - to assess the extent of flooding. According to the NDSI, NDWI indices and a combination of the red and infrared channels of the Sentinel-2 L2A satellite, the flooding of the floodplain of the Irpin River was traced, caused by the destruction of a hydraulic structure near the village of Kozarovichi. Wave abrasion of the shores was studied on the example of the Kremenchuk Reservoir near the villages of Pronozivka and Mozoliivka using Landsat4 (1984) and Landsat8 (2016) satellite images. The study of the reshaping of the coastline near the village of Tsybli in the Kyiv region used the method of determining spatio-temporal changes of the coastline as a result of its erosion. The assessment of spatio-temporal changes of the coastline should be carried out taking into account the water levels on the dates of the measurements. The conducted studies established that all the identified evaluation indicators can be grouped as biological, hydro morphological, and physicochemical, and it can be concluded that methodical approaches to assessing the ecological state of surface waters using satellite data are based on established cause-and-effect relationships of processes affecting water objects.

Antiviral potential of spirulina in individuals with human immunodeficiency virus or Hepatis C virus infections: A systematic review and meta-analysis

BackgroundSpirulina, a cyanobacterium or blue-green algae that contains phycocyanin, nutritional supplementation has been evaluated in patients living with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) due to its antiviral properties. This supplementation may be beneficial in low resource settings when awaiting antiretroviral therapy (ART) for HIV. This review aimed to evaluate the effectiveness of Spirulina supplement in antiviral-naïve HIV- and HCV-infected patients by assessing its immunological effect (Cluster of Differentiation 4 or CD-4 T-cell count) and disease progression (viral load). MethodsWe searched PubMed, Cochrane Library, Scopus, and Web of Science from inception through January 23, 2024. Two authors independently performed the study selection, data extraction, and risk of bias assessment. We pooled data by using a random-effects model and evaluated publication bias by a funnel plot. ResultsWe identified 5552 articles, 5509 excluded at the title and abstract stage with 44 studies making it to the full text review. Of these 6 studies met the eligibility for inclusion in the final analysis as follows:4 randomized controlled trials (RCTs) and 2 non-RCTs. The pooled results of the Spirulina intervention found significant improvements in biomarkers of clinical outcomes, viral load (VL) and CD4 T-cell (CD4) counts, in participants of the treatment group compared to controls; the VL had an overall Cohen’s d effect size decrease of -2.49 (-4.80, -0.18) and CD4 had an overall effect size increase of 4.09 (0.75, 7.43). [Cohen’s d benchmark: 0.2 = small effect; 0.5 = medium effect; 0.8 = large effect]. ConclusionsFindings from this systematic review showed a potential beneficial effect of Spirulina supplementation in HIV- and HCV-infected patients by increasing CD4 counts and decreasing viral load. However, further research in larger controlled clinical trials is needed to fully investigate the effect of this nutritional supplement on clinically relevant outcomes, opportunities for intervention, optimal dose, and cost-benefit of Spirulina supplementation.

C-phycocyanin reinforces autophagy to block pulmonary fibrogenesis by inhibiting lncIAPF biogenesis

Pulmonary fibrosis is a chronic and irreversible progressive lung disease caused by various factors, such as age and environmental pollution. With countries stepping into an aging society and the seriousness of environmental pollution caused by global industrialization, the incidence of pulmonary fibrosis is annually increasing. However, no effective drug is available for pulmonary fibrosis treatment. C-phycocyanin (C-PC), extracted from blue-green algae, has good water solubility and antioxidation. This study elucidated that C-PC reinforces autophagy to block pulmonary fibrogenesis by inhibiting long noncoding RNA (lncRNA) biogenesis in vivo and in vitro. Cleavage under targets and release using nuclease (CUT & RUN)-PCR, co-immunoprecipitation (Co-IP), and nuclear–cytoplasmic separation experiments clarified that C-PC blocked the nuclear translocation of activating transcription factor 3 (ATF3) to prevent the binding between ATF3 and transcription factor Smad3, thereby hindering lncIAPF transcription. Human antigen R (HuR) truncation experiment and RNA binding protein immunoprecipitation (RIP) were then performed to identify the binding domain with lncIAPF in the 244–322 aa of HuR. lncIAPF exerted its profibrogenic function through the binding protein HuR, a negative regulator of autophagy. In summary, C-PC promoted autophagy via down-regulating the lncIAPF–HuR-mediated signal pathway to alleviate pulmonary fibrosis, showing its potential as a drug for treating pulmonary fibrosis. Exploring how C-PC interacts with biological molecules will help us understand the mechanism of this drug and provide valuable target genes to design new drugs.

Seasonal Shifts in Diatom Species Dominance in the Tidal Mangrove Estuary of Bangladesh

Sustainable estuary management provides fishery resources, supports livelihoods and maintains estuarine food webs. However, these are highly dependent on hydrological factors and nutrients effects of the estuary itself. We studied seasonal phytoplankton quantity and composition of the Pasur River estuary in the Sundarbans mangrove forest, Bangladesh to understand the phytoplankton structure and identify potential indicators of environmental changes. Water and phytoplankton samples were collected at 11 different locations around the study region from January to December 2019 to assess spatial and temporal differences. Significant differences (p < 0.05) in the average salinity were observed between the dry and rainy seasons. Elevated phytoplankton (blue-green algae) concentrations were associated with decreased salinity while increased diatom abundance was linked to higher salinity. Phytoplankton succession from blue-green algae (wet season) to diatoms (dry season) occurred due to variations in physicochemical parameters and nutrient factors. Simultaneously, phytoplankton diversity and density were shown to change in response to habitat quality and seasonal variation. This study highlights the potential impacts of both human activities and natural factors on the population structure in these estuarine environments. J Bangladesh Agril Univ 22(2):231-240, 2024

Optimal N/P Ratio of the Shrimp Culture Waste Fertilizer For Growth Rate of Spirulina platensis

The cultivation of vaname shrimp produces waste with a high nutrient content. This waste can be used as fertilizer in microalgae culture like Sprulina platensis. However, the N / P ratio in shrimp culture waste is low, namely 5.5: 1, while the need for growth of blue-green algae ranges from 10:1 - 16:1. Therefore, it is necessary to regulate the N: P ratio in shrimp culture waste to match the needs of S. platensis. The purpose of this study was to determine the effect of different N / P ratios on shrimp culture waste fertilizer on the growth of S. plantesis. This study used a Completely Randomized Design (CRD) which was divided into 6 treatments with 3 replications, as P0: Walne fertilizer (N / P ratio 17: 1), P1: shrimp culture waste fertilizer enriched with urea (N / P ratio 5,5: 1), P2 with N/P ratio of 10.5: 1, P3 with N/P ratio of 15.5: 1, P4 with N/P ratio of 20.5: 1 and P5 with N/P ratio 25.5: 1. The parameters observed were density and growth rate of S. platensis and water quality namely: temperature, salinity, and pH. The data obtained were processed using Analysis of Variance (ANOVA) and continued with Duncan's multiple range test. The results of this study indicate that the application of shrimp culture waste fertilizer with different N/P ratios affect the population and growth rate of S. platensis. Shrimp culture waste fertilizer with a N: P ratio of 15.5: 1 (P3) is the best treatment for the growth of S. platensis because it produces the highest population and growth rate compared to the other treatments.

Пигментная система нитчатых цианобактерий в условиях аккумуляции ионов свинца

The effect of Pb (CH3COO)2 solutions with Pb2+ concentrations equal to 0.02, 0.1, 0.2 and 0.4 mM to strain of cyanobacteria (CB) Leptolyngbya sp. SK was studied. The duration of exposure of the culture with solutions was 21 days. During the experiment, measured the loss of lead ions in the solution; the increase in the biomass of CB was assessed as an indicator of culture adaptation; determined the content of photosynthetic pigments as indicators of maintaining the viability of the culture. The content of lead ions decreased in all variants, the maximum decrease was 96.2% – in the medium with a Pb2+concentration of 0.4 mM. An increase in the biomass of CB was observed in the presence of Pb2+ of all concentrations, the maximum increase in a solution with a Pb2+ concentration of 0.1 mM was up to 7.5 times. There was a decrease in the content of chlorophyll a in the biomass of CB, in comparison with the control, by 67.0–94.2% with an increase in the concentration of Pb2+ in the solution. Under the influence of solutions with Pb2+ concentrations of 0.02, 0.1, and 0.4 mM, the content of carotenoids in the biomass of cyanobacteria decreased by 48%, 75% and 92%, respectively; the concentration of Pb2+0.2 mM caused an increase in the content of carotenoids by 1% with the control. The inhibitory effect of all investigated concentrations of Pb2+ was noted on the complex of phycobilin pigments. The accumulation of lead ions from solutions with Pb2+ concentrations up to 0.4 mM, an increase in CB biomass in the presence of 0.1 mM Pb2+ and an increase in the synthesis of carotenoids at 0.2 mM Pb2+ may indicate adaptation of the studied culture to lead acetate.

Arthrospira platensis nanoparticles dietary supplementation improves growth performance, steroid hormone balance, and reproductive productivity of Nile tilapia (Oreochromis niloticus) broodstock.

This study evaluates the impact of dietary supplementation of the blue-green alga Arthrospira platensis NIOF17/003 nanoparticles (AN) on the growth performance, whole-body biochemical compositions, blood biochemistry, steroid hormonal, and fry production efficiency of Nile tilapia (Oreochromis niloticus) broodstock, during the spawning season. After a 21-day preparation period to equip the females and ensure that their ovaries were filled with eggs, mating between the mature females and males took place in a 3:1 ratio during a 14-day spawning cycle. A total of 384 tilapia broodstock 288 females and 96 males with an initial body weight of 450.53±0.75, were divided into four groups; AN0: a basal diet as a control group with no supplementation of Arthrospira platensis, and the other three groups (AN2, AN4, and AN6) were diets supplemented with nanoparticles of A. platensis at levels of 2, 4, and 6 g kg─1 diet, respectively. The results found that fish-fed group AN6 showed the highest significant differences in weight gain (WG), final weight (FW), feed conversion ratio (FCR), protein efficiency ratio (PER), and feed efficiency ratio (FER). Females fed the AN6 diet showed the highest significant fat content. Compared to the AN0 group, fish fed on the supplemented diets showed significant improvement (p < 0.05) in triglyceride, glucose, and aspartate aminotransferase (AST). A gradual increase in AN inclusion level resulted in a gradual increase in the concentrations of luteinizing hormone (LH), and follicle-stimulating hormone (FSH), testosterone, progesterone, and prolactin. The rates (%) of increase in fry production for females fed supplemented diets were 10.5, 18.6, and 32.2% for AN2, AN4, and AN6, respectively, compared to the control group. This work concluded that the inclusion levels of 6 g kg─1 of A. platensis nanoparticles in the diet of Nile tilapia broodstock significantly improved the growth performances, steroid hormone concentrations, and increased the fry production efficiency by 32.2%, respectively. These findings revealed that A. platensis nanoparticles resulted in a significantly enhanced female' reproductive productivity of Nile tilapia broodstock.

Potensi Spirulina Platensis Sebagai Sumber Kosmetik

Spirulina Platensis, a type of blue-green algae, has attracted the attention of the cosmetics industry due to its extraordinary nutritional and antioxidant properties. This microalgae is rich in vitamins, minerals, and amino acids, making it an attractive ingredient for skin care products. Methods used. The qualitative literature review research method is an approach used to collect, evaluate, and synthesize existing studies in the relevant scientific literature. with a specific topic. Based on research results, Spirulina platensis has great potential as a cosmetic ingredient that can provide benefits in caring for and protecting the skin. However, consult a medical professional or esthetician before using products containing Spirulina platensis.

Exudates of Microcystis aeruginosa on oxidative stress and inflammatory responses in gills of Sinocyclocheilus grahami

Early cyanobacterial blooms studies observed that exposure to blue-green algae led to fish gills impairment. The objective of this work was to evaluate the toxic mechanisms of exudates of Microcystis aeruginosa (MaE) on fish gills. In this study, the toxic mechanism of MaE (2×106 cells/mL) and one of its main components phytosphingosine (PHS) with two concentrations 2.9 ng/mL and 145 ng/mL were conducted by integrating histopathology, biochemical biomarkers, and transcriptomics techniques in Sinocyclocheilus grahami (S. grahami) for 96 h exposure. Damaged gill tissue with epithelial hyperplasia and hypertrophy, remarkable Na+/K+-ATPase (NKA) enzyme activity, disrupted the redox homeostats including lipid peroxidation and inflammatory responses were observed in the fish of MaE exposure group. Compare to MaE exposure, two concentrations of PHS exposure appeared to be a trend of lower degree of tissue damage, NKA activity and oxidative stress, but induced obviously lipid metabolism disorder with higher triglycerides, total cholesterol and total bile acid, which might be responsible for inflammation responses in fish gill. By transcriptome analysis, MaE exposure were primarily enriched in pathways related to gill function and immune response. PHS exposure, with higher number of differentially expressed genes (DEGs), were enriched in Toll-like receptor (TLR), Mitogen-Activated Protein Kinase (MAPK) and NOD-like receptor protein 3 (NLRP3) pathways. We concluded that MaE and PHS were induced the inflammatory responses, with oxidative stress-induced inflammation for MaE exposure but lipid metabolism disorder-induced inflammation for PHS exposure. The present study provided two toxin-induced gill inflammation response pathways under cyanobacterial blooms, which could be a scientific basis for the ecological and health risk assessment in the aquatic environment.

Enhancing french basil growth through synergistic Foliar treatment with copper nanoparticles and Spirulina sp.

BackgroundThis study investigates a novel idea about the foliar application of nanoparticles as nanofertilizer combined with a natural stimulant, blue-green algae Spirulina platensis L. extract, as a bio-fertilizer to achieve safety from using nanoparticles for enhancement of the growth and production of the plant. Thus, this experiment aimed to chemically synthesize copper nanoparticles via copper sulfate in addition to evaluate the impact of CuNPs at 500, 1000, and 1500 mg/L and the combination of CuNPs with or without microalgae extract at 0.5, 1, and 1.5 g/L on the morphological parameters, photosynthetic pigments accumulation, essential oil production, and antioxidant activity of French basil.ResultsThe results revealed that foliar application of CuNPs and its interaction with spirulina extract significantly increased growth and yield compared with control, the treatments of 1000 and 1500 mg/L had less impact than 500 mg/L CuNPs. Plants treated with 500 mg/L CuNPs and 1.5 g/L spirulina extract showed the best growth and oil production, as well as the highest accumulation of chlorophylls and carotenoids. The application of CuNPs nanofertilizer caused a significant increase in the antioxidant activity of the French basil plant, but the combination of CuNPs with spirulina extract caused a decrease in antioxidant activity.ConculosionTherefore, foliar application of natural bio-fertilizer with CuNPsis necessary for obtaining the best growth and highest oil production from the French basil plant with the least damage to the plant and the environment.

Insightful analysis of cyanobacterial-assisted degradation of different polymers and their kinetics

The usage of plastics has increased reliably over the years. Worldwide plastic pollution has grown to 460 million tons annually, increasing global greenhouse gas emissions by 3.4 %. In recent years, several studies have been performed utilizing microorganisms for bioremediation. The aggregation of microplastics affects marine aquatic life, posing a severe threat to the aquatic environment and hurting the global food chain. Bioremediation of various polymers is cost-effective and environmentally feasible compared to chemical, physical, and biophysical methods. Cyanobacteria, also known as blue-green algae, are photosynthetic organisms and can generate value-added products from waste, i.e., waste valorization and minimization. The present study uses Cyanobacterial sp. (Anabaena & Nostoc) to degrade the synthetic polymers prepared in lab-scale conditions. Weight loss of the degraded polymers was examined, and polymeric characteristics were analyzed through SEM, FTIR, XRD, and AFM. The experimental study observed that the polymers degraded by about 70 % and 82 % by Nostoc and Anabaena sp. in about eight weeks (approx. Two months). Polymers are degraded into monomers such as vinyl alcohol, ethylene, terephthalic acid, polycaprolactone from polyethylene terephthalate, and polyvinyl alcohol. They further break down into carbon dioxide, hydrogen, and water. These are identified from the LCMS-MS analysis. The experimental data for the degradation of polymers in Cyanobacteria sp. and control media fitted the Sinclair and Peppas kinetic model well. The results inferred that those cyanobacteria could degrade the polymers very effectively since it is a potent bioremediatory agent that can remove different organic and inorganic contaminants from the environment.

Towards nature-based production and valorization of cyanobacteria for the development of sustainable pigments and biomaterials

Cyanobacteria, also named blue-green algae, are one of the main oxygen producers in the oceans. This is developed through photosynthesis, a process in which solar power and carbon dioxide are captured to ensure the survival and proliferation of these microorganisms. Parallelly, cyanobacteria are outstanding candidates for transitioning towards cyclic recovery processes, as they can; i) easily propagate in waste effluents containing pollutants that they can remove, and ii) accumulate bioproducts, including blue pigments which are very scarce. Altogether, they suppose a sustainable subject for the manufacturing of biomaterials. This personal project called MATERCyan, aims to explore the potential of cyanobacteria to produce biodegradable materials and bio-based pigments, targeting to investigate the potential use of local waste sources for their formulation. Moreover, it focuses on assessing the durability of these pigments over time, by “immortalizing” them in natural matrixes. Finally, it pretends to encourage community building, as well as to fill the gap between scientists and local artists through the diffusion of simple and sustainable recipes.

Direct air capture using halophilic Cyanobacterium aponinum PCC10605 under illumination of light-emitting diodes in marine environment

Excessive carbon dioxide (CO2) emissions have become a disaster, calling for an effective way to reduce atmospheric CO2 content. Cyanobacteria, also known as blue-green algae, are potent natural carbon sinks with efficient photosynthesis and produce valuable compounds. Herein, we demonstrated the excellent properties of Cyanobacterium aponinum PCC10605 (Capo) in maintaining growth and protein accumulation under salt stress and red light-emitting diodes (LEDs) illumination at 660 nm under direct air capture (DAC) condition. Multi-factor optimization from response surface methodology revealed the best condition of 25 °C, 70 μE light intensity, 17 g/L salt, 16 to 8 h for light to dark period, and 6 mM nitrogen to yield the highest combination of 1.49 g/L biomass and 19.1 % C-phycocyanin (C-PC) content. Capo also thrived in 50 % seawater from Penghu, Taiwan where its DAC capacity was confirmed using an elemental analyzer, showing that 48.2 % carbon content was equivalent to specific capture ratio of 1.75 g-CO2/g-DCW and volumetric efficiency of 2.62 g-CO2/L, respectively. Finally, scaling up cultivation in 2-liter photobioreactor was successfully carried out under red LED illumination. The potential of Capo in reducing atmospheric CO2 level represents an advancement in sustainable biotechnology for climate change mitigation.

Tibetan terrestrial and aquatic ecosystems collapsed with cryosphere loss inferred from sedimentary ancient metagenomics.

Glacier and permafrost shrinkage and land-use intensification threaten mountain wildlife and affect nature conservation strategies. Here, we present paleometagenomic records of terrestrial and aquatic taxa from the southeastern Tibetan Plateau covering the last 18,000 years to help understand the complex alpine ecosystem dynamics. We infer that steppe-meadow became woodland at 14 ka (cal BP) controlled by cryosphere loss, further driving a herbivore change from wild yak to deer. These findings weaken the hypothesis of top-down control by large herbivores in the terrestrial ecosystem. We find a turnover in the aquatic communities at 14 ka, transitioning from glacier-related (blue-green) algae to abundant nonglacier-preferring picocyanobacteria, macrophytes, fish, and otters. There is no evidence for substantial effects of livestock herding in either ecosystem. Using network analysis, we assess the stress-gradient hypothesis and reveal that root hemiparasitic and cushion plants are keystone taxa. With ongoing cryosphere loss, the protection of their habitats is likely to be of conservation benefit on the Tibetan Plateau.

Phytoplanktonig Studies in River Hooghly

The river Hooghly flowing through Calcutta and Howrah has a high degree of pollutants. Present study revealed the sources of pollution with phytoplanktonic abundance in the stream. Samples were collected from 5 sites near Howrah and Calcutta from June 1985 to May 1986. Members of Bluegreen algae, Bacillariophyceae and Chlorophyceae were found during the study. Changes in physicochemical parameters due to pollution were observed. Several parameters were responsible directly and indirectly which occurred in Phytoplankton, population. A correlation between biological examination and chemical examination of river water has been made.

Spirulina versus metformin for controlling some insulin signaling pathway genes in induced polycystic ovary syndrome rat model

Polycystic ovary syndrome (PCOS) is a prevalent endocrinologic and gynecologic disorder that affects women of reproductive age; besides, insulin resistance (IR) occurs in 50–70 % of PCOS cases. Metformin (Met) is commonly prescribed for IR management; however, it does not affect IR with some gastrointestinal symptoms. Spirulina platensis (SP) is a blue-green alga that may increase insulin sensitivity. Therefore, our study aims to evaluate SP as an alternative treatment to Met for improving glucose homeostasis by assessing the expression of 11 crucial genes involved in the insulin signaling pathway. After induction of the PCOS model using dehydroepiandrosterone (DHEA) (60 mg/kg bwt) for 30 consecutive days, rats were allocated into six groups. Relative liver weight, glutamic pyruvic transaminase (GPT) serum levels, glutamic-oxaloacetic transaminase (GOT), and insulin were determined. Furthermore, the gene expression of Ins1, Irs1, Pik3ca, Prkcz, Foxo1, Srebf1, Ppargc1a, Pklr, Gk, G6pc, and Pepck in the rat's liver tissue was determined using qRT-PCR. Treatment of the PCOS control group with Met or SP revealed a decrease in all these parameters compared with the PCOS model. Additionally, we found a statistically significant difference in the expression of both the Gk and Prkcz genes. To summarize our study results, SP or Met supplementation to PCOS rats had almost the same effect on assessed relative liver weight, GOT, GPT, and insulin levels compared with PCOS control rats. If further studies confirm and detect more impact of SP on IR in PCOS, SP could be used instead of Met since the latter causes many side effects.

Analysis of Meteorological Drivers of Taihu Lake Algal Blooms over the Past Two Decades and Development of a VOCs Emission Inventory for Algal Bloom

Cyanobacterial blooms represent a common environmental issue in aquatic systems, and these blooms bring forth numerous hazards, with the generation of volatile organic compounds (VOCs) being one of them. Global climate change has led to alterations in various climatic factors affecting algal growth, indirectly impacting the quantity of VOCs released by algae. With advancements in remote sensing technology, exploration of the spatiotemporal distributions of algae in large water bodies has become feasible. This study focuses on Taihu Lake, characterized by frequent occurrences of cyanobacterial blooms. Utilizing MODIS satellite imagery from 2001 to 2020, we analyzed the spatiotemporal characteristics of cyanobacterial blooms in Taihu Lake and its subregions. Employing the LightGBM machine learning model and the (SHapley Additive exPlanations) SHAP values, we quantitatively analyzed the major meteorological drivers influencing cyanobacterial blooms in each region. VOC-related source spectra and emission intensities from cyanobacteria in Taihu Lake are collected based on the literature review and are used to compile the first inventory of VOC emissions from blue-green algae blooms in Taihu Lake. The results indicate that since the 21st century, the situation of cyanobacterial blooms in Taihu Lake has continued to deteriorate with increasing variability. The relative impact of meteorological factors varies across different regions, but temperature consistently shows the highest sensitivity in all areas. The VOCs released from the algal blooms increase with the proliferation of the blooms, posing a continuous threat to the atmospheric environment of the surrounding cities. This study aims to provide a scientific basis for further improvement of air quality in urban areas adjacent to large lakes.

Ecology and life cycle of the filter-feeding Amphipsyche meridiana Ulmer 1902 (Trichoptera: Hydropsychidae) in an irrigation canal, central Thailand

Ecology and life cycle of the filter-feeding Amphipsyche meridiana Ulmer 1902 (Trichoptera: Hydropsychidae) in an irrigation canal, central Thailand

Replenishment of landscape water with reclaimed water: threshold of hydraulic retention time employing transparency as a control indicator

ABSTRACT There exists a significant risk of water blooms during the utilization of recycled water in landscape environments. The nitrogen and phosphorus discharge standards of sewage treatment plants are very low. Controlling hydraulic retention time (HRT) is currently the most effective means to control water bloom. This article proposes a new method for determining the HRT threshold based on water transparency as a control indicator. The following results were obtained: (1) with the nitrogen and phosphorus concentrations of 15 and 0.5 mg/L, respectively, the threshold for HRT under high temperature and strong light is 4.6 days, while the threshold under low temperature and low light is 11.5 days. (2) With the nitrogen and phosphorus concentrations of 10 and 0.3 mg/L, respectively, the threshold for HRT under high temperature and strong light is 5 days, while the threshold under low temperature and low light conditions is 12.3 days. (3) The HRT threshold obtained under high temperature and strong light is lower than that obtained under low temperature and low light conditions. (4) The higher the concentrations of nitrogen and phosphorus, the smaller the HRT threshold obtained. (5) Blue algae have stronger adaptability than green algae and diatoms.

Hemato-biochemical and histopathological effects of blue-green algae, probiotic, and antibiotic in Cyprinus carpio L

Hemato-biochemical and histopathological effects of blue-green algae, probiotic, and antibiotic in Cyprinus carpio L