Frequent cyanobacterial blooms in reservoirs used for human supply increase the risk of noxious secondary metabolites, endangering human health and ecological balance, and requiring constant monitoring by water companies. Although hydrogen peroxide (HO) has been widely reported as an effective agent for the control of cyanobacteria, being Microcystis aeruginosa one of the most studied species, very limited data is available on its effects over Dolichospermum circinale. Therefore, this study aimed to evaluate the impact of HO on D. circinale and comparing it to the effects over the M. aeruginosa. The treatment was performed in cyanobacterial cultures with the application of 2 and 5 mg L of HO under visible light. To measure the impact of the treatment, intact cells were counted and cell re-growth monitored. Geosmin and microcystin, cell pigments, color, and organic matter in water were also analyzed during the treatment. The results showed that even the smallest HO concentration (2 mg L) was able to completely remove D. circinale cells. Although M. aeruginosa could only be completely removed using 5 mg L, the few cells remaining after the application of 2 mg L were not viable and did not re-grew after 15 days. Total microcystin concentration increased after M. aeruginosa was exposed to HO, suggesting that oxidative stress may increase the detection of this metabolite when the cells are lysed. While 2 mg L was able to significantly decrease total geosmin, the addition of 5 mg L did not improve removal. Chlorophyll-a was readily degraded after cell rupture but the same did not happen to phycocyanin, demonstrating its high resilience to this oxidant. Color and organic matter increased for the M. aeruginosa but decreased for the D. circinale suspension, probably because the higher concentration of the M. aeruginosa yielded more extracellular content to the water which was not able to be degraded by the amount of HO applied.
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http://dx.doi.org/10.1016/j.aquatox.2020.105735 | DOI Listing |
Microorganisms
December 2024
Department of Ecology and Institute of Hydrobiology, Jinan University, Guangzhou 510632, China.
Taste and odor (T/O) compounds are a global threat in drinking water, mainly produced by cyanobacteria in freshwater environments. Temperature plays a crucial role in regulating geosmin dynamics in temperate and subtropical lakes, while its influence may be lower in tropical waters. To better understand the factors affecting geosmin occurrence in tropical waters, a dataset from a field investigation conducted in a large tropical reservoir was analyzed.
View Article and Find Full Text PDFHarmful Algae
November 2024
Human and Eco-Care Center, Department of Environmental Health Science, Konkuk University, Seoul 05029, South Korea; Department of Environmental Health Science, Konkuk University, Seoul 05029, South Korea. Electronic address:
Cyanobacteria from the orders Nostocales and certain Stigonematales form akinetes, spore-like dormant cells that allow them to survive adverse environmental conditions. Temperature is known to be one of the key factors affecting akinete formation, but there is currently little known about akinete formation during cell growth over a wide range of temperature conditions and its relation to the overall survival strategy of cyanobacteria. Therefore, in the current study, we conducted a temperature-controlled experiment to analyze the akinete formation of a harmful cyanobacterium Dolichospurmum circinale using a growth chamber.
View Article and Find Full Text PDFSci Total Environ
November 2024
Department of Botany, Poznań University of Life Sciences, Dąbrowskiego 159, 60-594 Poznań, Poland.
Small and shallow water bodies are particularly sensitive to adverse conditions connected with anthropogenic eutrophication. As model systems, ponds are a good object for ecological research and monitoring of global environmental changes. We examined cyanobacteria along with other groups of algae versus zooplankton and abiotic characteristics of water in 51 aquatic ecosystems exposed to anthropogenic pressure (from natural forest to highly disturbed field ponds) with 3 distinct trophic groups: meso-, eu- and hypertrophic.
View Article and Find Full Text PDFChemistry
March 2024
Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8572, Japan) (M. Yotsu-Yamashita.
Saxitoxin (STX, 1) is a representative compound of paralytic shellfish toxins (PSTs) that are produced by marine dinoflagellates and freshwater cyanobacteria. Although several pathways have been proposed for the biosynthesis of STX, the order of ring and side chain hydroxylation, and formation of the tricyclic skeleton have not been well established. In this study, 12,12-dideoxy-decarbamoyloxySTX (dd-doSTX, 2), the most reduced STX analogue having the tricyclic skeleton, and its analogues, 12β-deoxy-doSTX (12β-d-doSTX, 3), 12α-deoxy-doSTX (12α-d-doSTX, 4), and doSTX (5), were synthesized, and these compounds were screened in the toxic microalgae using high-resolution LCMSMS.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
January 2024
Instituto Nacional de Limnología (CONICET-UNL), Ciudad Universitaria, 3000, Santa Fe, Argentina.
Insecticides are widely used for pest control and frequently reach aquatic systems, imposing a risk to the biota. In this work, the effect of environmental concentrations of bifenthrin on the grazing capacity of Simocephalus vetulus (Cladocera) and Argyrodiaptomus falcifer (Copepoda) on phytoplankton was evaluated. Fifteen microcrustacean individuals and a natural phytoplankton assemblage dominated by Cyanobacteria were exposed during 46 h to three concentrations of bifenthrin (C0 0 μg L, C1 0.
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