• ALGAE
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• v.28 no.1
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• pp.93-99
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• 2013

A freshwater cyanobacterium, Phormidium autumnale KNUA026, was isolated from puddles of icy water in Gyeongsan City, South Korea and its potential as a biofuel feedstock was investigated. Maximal growth was obtained when the culture was incubated at $25^{\circ}C$ and around pH 9.0. The total lipid content of the isolate was approximately 14.0% of dry weight and it was found that strain KNUA026 was able to autotrophically synthesize heptadecane ($C_{17}H_{36}$) which can be directly used as fuel without requiring a transesterification step. As this benthic cyanobacterium was capable of forming thick mats, it could be easily harvested by gravitational settling and this property may reduce the cost of production in commercial applications. Hence, P. autumnale KNUA026 appears to be a promising resource for use in the production of microalgae-based biofuels.

• ALGAE
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• v.32 no.3
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• pp.235-244
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• 2017

Freshwater algae living in shallow waters have evolved various photomovement to stay in the optimum light condition for survival. Previous action-spectra investigations showed that Spirogyra filaments have phototropic movement in blue light. To decipher the genetic control of phototropic movement, two phototropin homologues were isolated from Spirogyra varians, and named SvphotA and SvphotB. Both phototropins have similar molecular structure consisted of two light-oxygen-voltage domains (LOV1, LOV2) and a serine / threonine kinase domain. SvphotA and SvphotB had 48.7% sequence identity. Phylogenetic analysis showed SvphotA and SvphotB belong to different clades suggesting early divergence, possibly before the divergence of land plants from the Zygnematales. Quantitative PCR and northern blot analysis showed that SvphotA and SvphotB responded differently to red and blue light. SvphotA was consistently expressed in the dark and in blue light, while SvphotB was expressed only when the plants were exposed to light. When the filaments were exposed to red light, SvphotA was significantly downregulated whereas SvphotB was highly upregulated. These results suggest that the two phototropins may have different roles in the photoresponse in S. varians.

• ALGAE
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• v.32 no.3
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• pp.171-179
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• 2017

The strictly freshwater red algal order Batrachospermales has undergone numerous taxonomic rearrangements in the recent past to rectify the paraphyly of its largest genus Batrachospermum. These systematic investigations have led to the description of new genera and species as well as re-circumscription of some taxa. Specimens collected from two locations in the southeastern USA were initially identified as being allied to Batrachospermum sensu lato, but could not be assigned to any recognized species. Representative rbcL (plastid) and COI-5P (mitochondrion) sequences showed these specimens to be similar to each other and not closely matching the previously published sequence data for other Batrachospermum taxa. Comparison of sequence variation and morphology with a broader range of batrachospermalean taxa resulted in the proposal of a new monotypic genus Lympha mucosa gen. et sp. nov. to accommodate these specimens. Lympha mucosa is sister to members of a newly described genus Volatus, but the two genera are easily distinguished based on straight versus curved, twisted or spirally coiled carpogonial branch, respectively. This new taxon has morphological similarities to Batrachospermum sections Turfosa and Virescentia, but can be differentiated based on genetic divergence in rbcL and COI-5P as well as a combination of morphological characters: dense, compressed whorls, axial carposporophytes with a single type of gonimoblast filament; cortication of the main axis closely appressed; and short, straight carpogonial branch arising from the pericentral cell and carpogonia with unstalked, lanceolate trichogynes. This new taxon adds to the freshwater red algal diversity of the southeastern USA, a region already known for biodiversity and high endemism of the aquatic flora and fauna. It is also a relevant new addition to the taxonomic knowledge of the freshwater red algal Batrachospermales.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.124.2-124
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• 1996

No Abstract, See Full Text

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.1
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• pp.62-69
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• 2000

The study was performed to apply the algae removal system to coagulation-filtration process for minimize the damage to screen interruption of water treatment plants and died of fish by algae bloom on freshwater. Sample used Nokdong river water and Alkalinity, turbidity, chlorophyll-a and pH measured using Jar test and drum filter for coagulation-filtration process to determine optimum coagulation condition. A jar test apparatus and laboratory reactor were used in this study. The highest removal efficiency was observed when condition of flocculation time, coagulant dosage, drum filter rpm and chlorophyll-a concentration were to be 5min, 5mg/ℓ, 3rpm and 90㎍/ℓ, respectively. The average removal efficiencies measured of chlorophyll-a and turbidity using Alum were 50～60% and 30～50%, respectively. PAC was more effective than Alum in removal chlorophyll-a about 20%.

• Journal of environmental and Sanitary engineering
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• v.10 no.1
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• pp.45-65
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• 1995

Seasonal occurrences and dynamics on the freshwater algae were examined in the upstream of the Yongsan river system with the Kwangju service water area from 1993 to 1994. Three hundred and three taxi were totally collected and composed of 6 classes, 15 orders, 7 suborders, 31 families, 74 genera, 248 species, 48 varieties and 7 forma. Compositions in each algal class were divided in 136 taxi of Chlorophyceae(44.8% ), 109 taxi of Bacillariophyceae(36.0% ), 30 taxa of Cyanophyceae(10.1% ), 21 taxa of Euglenophyceae(6. 9% ),4 taxi of Chrysophyceae(1.3% ) and 3 taxa of Dinophyceae(1.0% ). The occurrence of taxa was a markedly decrease(-62) between summer and autumn, the critically increase(+43) between spring and summer. And also, it was indicated that the high frequency of taxa in summer, but the high standing biomass In winter in spite of low taxi. In general, it has much algal biomass in station 9 and 10, but low in station 4, 5 and 11, relatively. Through this survey, the major dominant taxa in algal biomass, Microcystis aeruginosa, Melosira varians, Synedra ulna and Navicula cryptocephala, they were all above 2.1×10$^{6}$ce11s/1, 13.2% of totals. There are about 10% of new emigrated taxa by season and they showed a remarkable succession. We may suggested that this system was well sustained for the habitat of freshwater algal community with low dominance and high diversity. Twenty three of nuisance algae including of Microcystis aeruginosa, Peridinium willei and Anabaena flos-aquae were distributed as if had low appearance. Of course, many of them were saprobiontic taxa, extraordinary growttung groups depend on organic loading in water system and also it was not showed severe algal blooming phenomenon.

• Environmental Engineering Research
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• v.22 no.1
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• pp.1-11
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• 2017

One of the most threatening consequences of eutrophic freshwater reservoirs is algal blooming which typically occur after the long a mega drought or/and irregular rainfall under influence of climate change. The long-term experiences of chemical treatment are known as a most practical effort to reduce health concerns from human exposure of harmful cyanobacteria as well as to preserve ultimate freshwater resources. Even though these conventional chemical treatment methods do not completely solve the algal residue problem in water treatment plant or directly in the water bodies, they still have big advantages as fast and efficient removal process of cyanobacteria due to cheaper, easier to manage. This review summarizes their chemical treatment scenarios of the representative coagulants, pre-oxidants and algaecides composed to chemical compounds which immediately may help to manage severe cyanobacteria blooms in the summer seasons.

• ALGAE
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• v.19 no.2
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• pp.139-144
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• 2004

Six taxa of unrecorded Korean species of genus Cosmarium were collected from several freshwater sites of South Korea in 2003. They were 3 species and 3 varieties of Genus Cosmarium. Genus Cosmarium of Korea was reported to totally 273 taxa 125 species, 113 varieties and 35 forms including this study.

• ALGAE
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• v.22 no.3
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• pp.167-183
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• 2007

Fifty-six taxa of chlorococcales were recorded from different water bodies of eastern and north-eastern states of India. These belong to 21 genera, e.g. Chlorococcum (1), Truebaria (1), Pediastrum (9), Hydrodictyon (1), Botrycoccus (1), Coenochloris (1), Radiococcus (1), Coenocystis (1), Oocystis (1), Glaucocystis (1), Chlorella (1), Kirchneria (2), Kirchnereilla (1) Ankistrodesmus (10), Coelastrum (3), Actinastrum (2), Tetrastrum (1), Crucigenia (1), Crucigeniella (1) Desmodesmus (6) and Scenedesmus (9). All these species were recorded first time from this region and out of these 16 species reported first from India.

• Journal of Ecology and Environment
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• v.37 no.4
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• pp.341-350
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• 2014

In this study, aquatic and aerial algae were collected in various environments in Hongcheon-river of Gangwan-do between December 2011 and June 2012, with the aim of adding newly described genera and species to the Korean flora. As a result, five genera and eight species were recorded for the first time in Korea. These newly recorded genera and species were Cylindrocapsa geminella, Leptosira mediciana, Pseudendoclonium basiliense var. brandii, Stichococcus minor, S. deasonii, Eustigmatos polyphem, Nephrodiella lunaris, and Xanthonema exile. The eight taxa identified in this study mostly corresponded to their reported morphological characteristics. However, some differences from previous published descriptions were found; N. lunaria, reported to be an aquatic species in a previous study, was found to be an aerial algae inhabiting on rocks and mosses. Cylindrocapsa geminella was found to transform into attached or planktonic algae depending on the environmental condition, and the cell wall was found to be changed. Likewise, E. polyphem was seen to change cell-shape or chloroplast color according to the environment.