• ALGAE
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• v.33 no.2
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• pp.143-156
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• 2018

Dolichospermum is a filamentous and heterocytous cyanobacterium that is one of the commonly occurring phytoplanktons in the Han River of Korea. Morphological observations led to the identification of D. planctonicum-like filaments in seasonal water samples. In the present study, we successfully isolated these filaments using culture methods, and examined its morphology using light and scanning electron microscopy. The morphology of the D. planctonicumlike species differed from that of typical D. planctonicum; it had thin cylindrical-shaped akinetes, which were narrower towards the ends than at the center. This morphology is firstly described in the genus Dolichospermum. In addition, the akinetes in the filament developed solitarily and were distant from the heterocytes. Phylogenetic analysis of the 16S rRNA sequences showed that our Dolichospermum clustered with D. planctonicum and D. circinale, which have coiled trichome. However, phylogenetic analysis of the gene encoding rivulose-1,5-bisphosphate carboxylase (rbcLX) clearly separated our species from other Dolichospermum, forming a unique clade. Additionally, structures of D. planctonicum and D. hangangense strains were different type in Box-B and V3 region. These results demonstrated that the new Dolichospermum species was unique in morphology and molecular traits. Therefore, we propose this to be a new species belonging to genus Dolichospermum with the name Dolichospermum hangangense sp. nov.

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.28-34
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• 2019

This study analyzed the occurrence pattern of Dolichospermum (= Anabaena) in the Bukhan river from March 2012 to December 2014 in order to identify the genotypes of Dolichospermum. Furthermore, 16S rRNA were analyzed to identify the genotypes of Dolichospermum that occurred in 2015 which were then compared to the reference sequence deposited at NCBI. During this period, the occurrence of Dolichospermum was highly correlated to water temperature. In the year 2012 and 2013, Dolichospermum appeared in Lake Cheongpyeong (CP), Sambong (SB), and Lake Paldang (P2) between July and August. However, in 2014, it appeared in SB and P2, but not in CP. This reduction in appearance was attributed to the decreased inflow to Lake Uiam as a result of low rainfall in 2014 as compared to 2012. In July 2015, the Dolichospermum 16S rRNA genotype was confirmed in five locations; Lake Cheongpyeong (CP), Seojong (SJ), Songchon Sewage Treatment Plant (SC), Joan (P4), and Lake Paldang (PD). Anabaena crassa of spiral clone, A. planctonica of linear clone, and A. circinalis of spiral clone exhibited high genetic similarity with the reference sequence. The 16r RNA genotype showed approximately 3 % sequence variation between the locations and were more similar to each other in locations that were closer.

• Korean Journal of Ecology and Environment
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• v.56 no.1
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• pp.14-35
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• 2023

Freshwater and brackish blue-green algae were collected at 43 freshwater and brackish sites (including lakes, ponds, swamps, streams, and rivers and estuaries) throughout South Korea from March 2017 to October 2018, and were identified using light microscopy. A total 223 taxa in freshwater and 230 taxa in brackish waters in 2017 and 274 taxa in fresh and brackish waters in 2018 were identified and among them, 20 taxa were unreported taxa of blue-green algae in Korea; The new recorded taxa were Aphanocapsa marina, Calothrix fusca f. durabilis, Calothrix littoralis, Calothrix parva, Chamaesiphon minimus, Chroococcidiopsis cubana, Chroococcidiopsis fissurarum, Coelosphaerium aerugineum, Dolichospermum mendotae, Eucapsis alpine, Gomphosphaeria cordiformis, Gomphosphaeria natans, Merismopedia danubiana, Lynbya aestuarii var. gaditana, Tolypothrix tenuis, Pseudocapsa maritima, Pseudocapsa sphaerica, Pseudophormidium tenue, Trichodesmus sp. and Woronichinia elorantae.