Fe2+ activating sodium percarbonate (SPC) to enhance removal of Microcystis aeruginosa and microcystins with pre-oxidation and in situ coagulation

Abstract Grazing of zooplankton on phytoplankton may contribute to a reduction of harmful cyanobacteria in eutrophic waters. However, the feeding capacity and interaction between zooplankton and toxic cyanobacteria vary among grazer species. In this study, laboratory feeding experiments were designed to measure the grazing rate of the copepod Cyclops vicinus on Microcystis aeruginosa and the potential microcystin (MC) accumulation in the grazer. Copepods were fed a mixed diet of the edible green alga Ankistrodesmus falcatus and toxic M. aeruginosa for 10 days. The results showed that C. vicinus efficiently ingested toxic Microcystis cells with high grazing rates, varying during the feeding period (68.9–606.3 Microcystis cells animal-1 d-1) along with Microcystis cell density. Microcystis cells exhibited a remarkable induction in MC production under grazing conditions with concentrations 1.67–12.5 times higher than those in control cultures. Furthermore, C. vicinus was found to accumulate MCs in its body with concentrations increasing during the experiment (0.05–3.21 μg MC animal-1). Further in situ studies are needed to investigate the ability of Cyclops and other copepods to assimilate and detoxify MCs at environmentally relevant concentrations before deciding on the biocontrol of Microcystis blooms by copepods.

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A new fluorescent oligonucleotide probe for in-situ identification of Microcystis aeruginosa in freshwater

Microchemical Journal ◽

10.1016/j.microc.2019.05.017 ◽

2019 ◽

Vol 148 ◽

pp. 503-513 ◽

Cited By ~ 1

Author(s):

A. Barra Caracciolo ◽

L. Dejana ◽

C. Fajardo ◽

P. Grenni ◽

M. Martin ◽

...

Keyword(s):

Microcystis Aeruginosa ◽

Oligonucleotide Probe

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Extracellular phosphatase activity of freshwater phytoplankton exposed to different in situ phosphorus concentrations

Marine and Freshwater Research ◽

10.1071/mf04283 ◽

2005 ◽

Vol 56 (4) ◽

pp. 417 ◽

Cited By ~ 29

Author(s):

A. Ŝtrojsová ◽

J. Vrba ◽

J. Nedoma ◽

K. Ŝimek

Keyword(s):

Enzyme Activity ◽

Phosphatase Activity ◽

Microcystis Aeruginosa ◽

Image Cytometry ◽

Phosphorus Concentration ◽

Phytoplankton Species ◽

Freshwater Phytoplankton ◽

Fragilaria Crotonensis ◽

Species Specific

Extracellular phosphatase production and biomass change were investigated in phytoplankton species transplanted from the phosphorus-limited dam area of a eutrophic reservoir and exposed to the phosphorus-sufficient inflow part and vice versa. Extracellular phosphatase activity was studied using the enzyme-labelled fluorescence (ELF) technique, allowing for direct microscopic detection of enzyme activity and, moreover, its quantification using image cytometry. Several phytoplankton species (e.g. Anabaena planctonica, Microcystis aeruginosa, Fragilaria crotonensis, Ankyra ancora and Planktosphaeria gelatinosa) regulated phosphatase activity according to external phosphorus concentration. On the contrary, picocyanobacteria and several green algae (Coelastrum microporum, Crucigeniella sp., Pediastrum tetras, and Staurastrum planctonicum) did not produce extracellular phosphatases at all. The species-specific extracellular phosphatase activity of F. crotonensis, A. ancora, and P. gelatinosa ranged between 0.02 and 3.5 fmol μm−2 h−1.

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Self-floating Capsule of Algicidal Bacteria Bacillus sp. HL and its Performance in the Dissolution of Microcystis Aeruginosa

10.21203/rs.3.rs-823541/v1 ◽

2021 ◽

Author(s):

Jinjie Huang ◽

Wenyi Zhang ◽

Mingchen Xu ◽

Linqiang Mao

Keyword(s):

Dissolution Rate ◽

Microcystis Aeruginosa ◽

Ethyl Cellulose ◽

Antioxidant Response ◽

Algicidal Bacteria ◽

Practical Application ◽

Free Living ◽

Mda Content ◽

Living Bacteria

Abstract Algicidal bacteria is known as efficient and environmentally friendly in treating Microcystis aeruginosa (M. aeruginosa). However, the practical application of algicidal bacteria in the natural water is limited by the interference of external factors and the low reuse capability. In this study, a biodegradation capsule for M. aeruginosa is prepared by biocompatible sodium alginate (SA) compositing with eco-friendly ethyl cellulose (EC). Bacterial strain HL was immobilized and the capsule was obtained under optimal usage concentrations of SA, Calcium chloride (CaCl2) and EC at 2%, 3% and 3%. It has been observed that capsules immobilizing bacteria HL shows considerable advantages over traditional bio-treatment systems (free-living bacteria) and good reusability performance. A better dissolution rate of 77.67% ± 1.14% on the 7th day was obtained with the embedding of algicidal bacteria at 50 mL, which enhanced algae dissolution rate by 11.05% compared with free-living bacteria, and the dissolution rate for M. aeruginosa still reaches 68.57% ± 2.88% after three times repetitive use. Algicidal bacteria capsules were examined on the fluorescence and antioxidant system of M. aeruginosa. It was indicated that photosynthetic mechanisms of M. aeruginosa were destroyed, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) were all significantly induced as antioxidant response, and malondialdehyde (MDA) content increased. Overall, capsules prepared in this study can provide a desirable environment for algicidal bacteria HL and ensure algicidal bacteria to in-situ work well in the inhibition of algae.

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