• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.791-799
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• 2015

This study focuses on the algae growth restraining. Many researches on a critical damage from algae growth are published, but it is hard to find how th restrain. Abnormal algae increasing is a problem, because it makes red tides, biodeterioration, etc. Therefore this study aims to decrease the damage from algae growth. Some metal ions have been used microorganism killing materials from old times. Especially, Cu ions are highly effective. Based on these uses of the metal ions, a functional mortar which restrains algae growth is developed. The mortar contains soluble glass which dissolve in water. The soluble glass was made of Cu ions and phosphates. When the soluble glass is dissolved, Cu ions are soaked out stably from the soluble glass. Culture mediums which incubate algae were made to evaluate the developed mortar specimens. Culture mediums were filled with fresh water and sea water. Algae were incubated for fourteen days in culture mediums. The evaluating methods are measuring volume of the dissolved organic carbon and the chlorophyll. Using these two measurements, the mortar specimens are judged that can restrain algae or not. According to the result, the functional mortars of culture medium filled with fresh and sea water shows similar trend. The functional mortar for restraining algae growth performs that's role well.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.362-367
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• 2009

Among total 176 strains with antialgal effects isolated from So-ok stream in Korea, Pseudomonas aeruginosa AJ1 showed the highest removal efficiency for an algal species Microcystis aeruginosa (clear zone of diameter 50.0 mm on algal lawn after 20 days). The algal growth was suppressed even when the supernatant of AJ1 culture was applied, suggesting that extracellular substances are responsible for its antialgal activity. The removal activity of AJ1 was optimal under the following condition: pH 8, $30^{\circ}C$, and mannitol as a carbon source. The antialgal activity of AJ1 appeared to be dependent of the growth phase of M. aeruginosa, i.e., the highest at the early phase, but not its own phase. As expected, the algicidal effect was improved as the amount of the treated supernatant was increased; the highest removal efficiency (80.3%) was achieved when 40 ml/L of the supernatant was used. Interestingly, however, the removal rate was opposite. The highest removal rate ($8.2{\mu}g$ chl-a/ml supernatant/day) was achieved when low concentration (10 ml/L) was applied. These results suggest that P. aeruginosa AJ1 is a promising biological agent to control the problematic algal bloom.

• Korean Journal of Ecology and Environment
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• v.33 no.2 s.90
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• pp.136-144
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• 2000

M. aeruginosa isolated from Lake Paldang was cultured in CB medium, and then each wet plants put into the cultured medium at a rate of 0.5 g and 2.5 g wet wt/l. There was slight inhibition by the input of cattail and iris of each 0.5 g wet wt/l cultured medium, but showed no reduction in algal growth in other flasks. Among the applied plants, ginkgo, pine needles, big cone pine, waterreed and water chestnut had an effect on inhibition of algal growth at the input of 2.5 g wet wt/l. Plants which were dried for 3 days at $50^{\circ}C$ introduced into the testing flask for 10days cultured at dose rates of 2.5 g/l. When chlorophyll a concentration was remarkably high as $802.6\;{\mu}g/l$ after five days, there was noticeably less chlorophyll compared with control at a rate of 98% by big cone pine, 96% by ginkgo, 95% by pine needles and 86% by rice straw, respectively. To examine the effect of plant extracts on algal growth, big cone pine and water chestnut were put to the amount of 1.25 g liquid extracts/l. Chlorophyll a concentration and cell density decreased to the extent of average 43% as compared with the beginning of experiment, but when concentration of chlorophyll a increased a most high, the inhibition of algal growth by liquid extracts did not affect at all. When a quantity of plant equivalent to 2.5 g liquid extracts/l inhibited the growth of algae by 95% after nine days.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.304-310
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• 2000

Enclosure experiments to reduce the growth of Cyanophyceae were carried out using plants in Kyongan stream. Wet plants put into the enclosure at a rate of 2.5 g wet wt/l and at that time, the average concentration of chlorophyll a was ranged from 30 to $50\;{\mu}g/l$. The dominant species was Microcystis aeruginosa. Ginkgo, big cone pine and pine needles significantly inhibited the growth of Microcystis from the early days to the stages of log-Phase. Waterchestnut was the most inhibitory to the growth of Microcystis. Pine needles inhibited in 85% of the algal growth: ginkgo in 80%; big cone pine in 75%; waterchestnut in 78%; wildrice in 59%; and iris in 30%. At the treatment with 0.25 g dried plants/l, algae was declined at a rate of 90% by waterchestnut: 53% by pine needles. Phenolic compounds were purifled from decomposing big cone pine and waterchestnut.

• Clean Technology
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• v.21 no.4
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• pp.257-264
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• 2015

Conventional physicochemical technologies for algae growth inhibition have economical and environmental pollution problems. This study attempted to overcome the problems by nature-friendly biological inhibition technology using fibrous carrier. The experimental results showed that the most effective carrier material, polyester, exhibited the highest biofilm thickness. The removal efficiency for nutrient salts, such as nitrogen and phosphorous, and algae growth inhibition of polyester carrier was 14.59%, 6.36%, and 77%, respectively, which is higher than for control group. These result indicate that the polyester carrier is available in eutrophic lake.

• Journal of Wetlands Research
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• v.7 no.3
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• pp.67-73
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• 2005

At research, the river's water which the sewage treatment facility will ask growth suppression the algae in the artificial rivers which it is using or it researched the method for the removal of the algae which grew. At results, when 60ppm of Chlorine was put in, the possibility of getting the result where 90% chlorophyll-a was removed and LC50 was 0.8ppm. The algae did not create even after 20days by which uses prevent agent of creation of the algae. Controlling the chlorine almost there was not an extinction effect of the algae which was already in large quantities multiplied, with in the effect against an water ecosystem widely known it is not. The prevent agent could inhibit creation of the algae, but it was judged with the fact that the methods are directly applied to the field must be researched continuously.

• Korean Journal of Ecology and Environment
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• v.35 no.2 s.98
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• pp.123-132
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• 2002

Experiments have been carried out in barge enclosure near Bukhangang area and arificially eutrophicated pond. Applied plants are three terrestrial plants (Big cone pine, Pine needles and Ginkgo) and one aquatic plant (Water chestnut). In the experiment pond, applied plants are big cone pine, pine needles and ginkgo at the concentration of 0.5 g/l and water chestnut of 0.3 g/l. And it used pine needles at the concentration of 0.3 g/l in barge enclosure. The dominant species was Microcystis aeruginosa. Chlorophyll a concentration decreased to the extent of average 65% as compared with the beginning of experiment by the input of big cone pine and pine needles in artificially eutrophicated pond. But it was decreased to the extent of average 34% by the input of water chestnut. Especially, pine needles significantly inhibited the growth of algae from the early days in barge enclosure, it was declined at a rate of average 74%. It was proved that pine needles was the most inhibitory to the growth of algae at the treatment with $0.3{\sim}0.5\;g/l$, Ginkgo and water chestnut are needed more study. We purified that the dissolved phenolic compounds from the various plants can affect algal growth.

• Korean Journal of Environmental Biology
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• v.34 no.2
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• pp.91-96
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• 2016

This study presents the potentiality of harmful algal bloom (HAB) control through the zooplankton, Daphnia magna. In case of co-cultivated D. magna with cyanobacteriums (Microcystis aeruginosa, Anabaena variabilis, and Limnothrix planctonica), the D. magna showed the $80.2{\pm}4.2%$, $39.7{\pm}4.0%$, and $25.9{\pm}10.9%$ of control efficiency for M. aeruginosa, A. variabilis and L. planctonica, respectively. Furthermore, algal control was investigated by using supernatant including metabolite/secretion of D. magna. The algal control efficiencies of supernatant were recorded as $24.9{\pm}9.9%$ and $8.9{\pm}4.0%$ for M. aeruginosa and A. variabilis, respectively. From the results of present study, it may be possible to provide a feasible way for development of eco-friendly HAB control methods.

• Ecology and Resilient Infrastructure
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• v.9 no.3
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• pp.183-193
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• 2022

The growth inhibitory effect of Microcystis aeruginosa according to the ultrasonic irradiation time was evaluated using a large algae sample volume (10 L) for various ultrasonic irradiation times (0.5, 1, 1.5, 2, 2.5 and 3 hr) at a laboratory scale. Based on the analysis of Chl-a and cell number of M. aerginosa, algae growth inhibition was observed with the decrease in Chl-a and cell number in all experimental groups after the ultrasonic irradiation. For the experimental group (T_B, T_C, T_D) with an ultrasonic irradiation time of less than 2 hours, rapid regrowth of algae was observed after growth inhibition, but the experimental group (T_E, T_F, T_G) with an irradiation time of more than 2 hours successfully inhibited algal growth lasting one or two more days. Based on the comparison of the recovery time to initial cell number the experimental group (T_B, T_C, T_D) took less than 20 days whereas the experimental group (T_E, T_F, T_G) took about 30 days. Correspondingly, the experimental group showed a high first order decay rate (𝜅) in proportion to the ultrasonic irradiation time during the growth inhibition period. Additionally, the specific growth rates (𝜇) during regrowth in the experimental group with irradiation time of more than 2 hours were relatively low compared to those in the experimental group with less than 2 hours. Therefore, ultrasonic irradiation for more than 2 hours is required for long-term (30 days) inhibition of algal growth in stagnant waters. However, the appropriate ultrasonic irradiation time for algae growth inhibition should be determined according to various field conditions such as the volume of stagnant water, water depth, flow rate, algae concentration, etc. Finally, damages to the algal cell surface and cell membrane were clearly observed, and both destruction and disturbance of gas vesicles of M. aeruginosa in the experimental group were discovered, indicating the growth inhibitory effect of Microcystis aeruginosa according to the ultrasonic irradiation time was confirmed.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.304-312
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• 2005

Effects of two endocrine disrupters (EDs) , nonylphenol (NP) and diethylhexyl phthalate (DEHP), on the population growth and morphology of two freshwater HABs (harmful algal blooms) , Microcystis aeruginosa and Stephanodiscus hantzschii, which frequently evoked the hazard bloom in an eutrophic lakes and reservoirs worldwide, were examined with seven different concentrations of EDs (0.01, 0.05, 0.1, 1,2, 2.5 and 3 ppm). Even at concentration below 0.01 ppm, NP strongly inhibited the algal growth of both M. aeruginosa and S. hantzschii, regardless of the algal growth phase. Morphologically, the algal cell treated with NP gradually lost green color in cytoplasm, became smaller in cell size, and then, was hardly seen in microscopic field. On the other hand, DEHP employed did not affect two algae at all concentrations, and rather stimulated the growth by about 10% with a treatment at 3.00 ppm compared to control. These results indicate that the continuous input of EDs, DEHP into the natural water system plays a crucial role to enhance or help an outbreak of algal bloom in eutrophic waters.