INTRODUCTION

Benthic cyanobacteria are classified according to the substrates; epiphytic (submerged plants or other algae), epilithic (rocks or stones), epipelic (mud) and epizoic (crustacean or arthropod). Some of cyanobacteria that have symbiotic relationship with lichen or bryophytes exposed to the atmosphere (Goyal 1997). Rocks exposed to the atmosphere are inhabited by extremophilic cyanobacteria that play a basic role as primary producers in a variety of subaerial habitats such as cliffs and pinnacles of dry and humid regions (Pentecost and Whitton 2000), hot and cold deserts (Wynn-Williams 2000; Vincent 2007) and caves (Hoffmann 2002), and might contribute to the future colonization of other planets (Grilli Caiola and Billi 2007; Billi 2012).

Cyanobacteria have both positive and negative influences on human and environment. They are an important component of microbial food webs and grazed biomass in water environments (Gonzalez et al. 1998; Charpy 2005). Spirulina had been used to food for livestock and human, and they are being developed as substitutional foods for their high content of protein, vitamin, mineral and so on (Graham et al. 2009).

But nowadays, freshwater habitats are threatened worldwide because of cyanobacteria, such as Oscillatoria, and Aphanizomenon. They produces odorous materials like Geosmin and 2-MIB (Robarts and Zohary 1987; Codd 1995; Graham et al. 2009; Whitton 2012). Therefore, continuous researches of cyanobacteria, especially Microcystis, Anabaena, Oscillatoria, and Aphanizomenon are being conducted worldwide (Park and Kim 1995; Park 2005; Lee et al. 2017).

The 4,617 taxa of cyanobacteria have been reported to AlgaeBase (Guiry and Guiry 2018), and 377 taxa have been reported in Korea (Kim 2015; Song and Lee 2017; Yim et al. 2017). Cephalothrix and Cyanophanon have been reported each 2 taxa and Toxifilum reported 1 taxa in world-wide (Guiry and Guiry 2018).

For this study, we collected unrecorded cyanobacteria from fresh and brackish waters to add the cyanophycean flora of Korea.

MATERIALS AND METHODS

We collected benthic and subaerophuytic cyanobacteria from six sites in Korea from April 2017 to April 2018 (Fig. 1; Tables 1, 2). Benthic cyanobacteria were collected scrubbing off submerged plants or rocks using soft brush. Subaerophytes were collected from lichen or bryophytes using sharp spatula. Each sample was sealed in sterile bottles and transported them to the laboratory (Crispim et al. 2004). Measurement of salinity was performed by marine tester (DMT-10, DYS, Korea).

The samples were examined under BX53 light microscope at ×400-1,000 (Olympus, Tokyo, Japan) and photographed using AxioCam HRC camera (Carl Zeiss, Oberkochen, Germany). The taxonomic classification system was based on Komárek et al. (2014) and Algaebase (Guiry and Guiry 2018). In this study, identification of cyanobacteia referred to Hirose et al. (1977), Prescott (1982), Chung (1993), Komárek and Anagnostidis (1999, 2005), John et al. (2011) and Komárek (2013).

RESULTS AND DISCUSSION

Three genera and seven species of benthic and subaerophytic cyanobacteria were newly recorded in Korea. The newly recorded genera were Cephalothrix, Cyanophanon and Toxifilum, and the newly recorded species were Anagnostidinema pseudacutissimum, Calothrix elenkinii, Cephalothrix komarekiana, Cyanophanon mirabile, Cyanosarcina chroococcoides, Leptolyngbya ectocarpi and Toxifilum mysidocida.

Cyanosarcina chroococcoides (Geitler) Kovácik 1988 (Fig. 2)

Synonym:Myxosarcina chroococcoides Geitler 1927

The colonies are microscopic and shaped subspherical or irregularly rounded with different sizes. The colony is composed of densely and irregularly aggregated packets of cells in different sizes. The mucilaginous envelope that surrounds the colony is thin (about 1 μm thick), firm and colourless. The mucilaginous envelope tightly surrounds the cell packets, sometimes diffluent in old colonies. The cell is irregularly rounded and olive-green or blue-green colored. The cell diameter is 8-12 μm.

Ecology: This species lives in moorland waters and swamps. Maybe they have wide distribution over the whole temperate zone (Komárek and Anagnostidis 1999). In this study, we collected this species from subaerophytic substrate (the wall of residential area).

Distribution: Europe: Spain (Alvarez-Cobelas and Gallardo 1988); South America: Argentina (Tell 1985); Asia: Japan (Hirose et al. 1977).

Site of collection: The wall of residential area, Dobong-gu, Seoul (February 10, 2018).

Specimen Locality: ACKU2018MD01

Calothrix elenkinii Kossinskaja 1924 (Fig. 3)

The thallus is composed of elongated clusters, also producing solitary filaments. Filaments exist solitarily, in groups or clusters. Filaments are fasciculated, arcuated, and entangled together at the bases. Sheaths are thin, not lamellated, colorless; they are open at the apex and usually longer than the trichomes. The width excluding the sheath is 5.5-7 μm at the basements and 5-6.5 μm wide at the middle parts. There are solitary heterocysts at the basement’s apex, with 4.5-7 μm width. At the basements, constricted at the cross-wall strongly appears, but slightly constricted crosswalls appear at the opposite end (apical regions). Trichomes are blue-green or olive-green colored and apical cells are narrowed and rounded. Cells are quadratic or a little shorter than long, but elongated and longer than wide in the upper part.

Ecology: This species appears in freshwater and benthic habitat. They lives in streams and soils (Komárek 2013). We collected it from eutrophic small pond.

Distribution: Europe: Spain (Mateo et al. 2006); South America: Argentina (Tell 1985); Asia: Russia (Medvedeva and Nikulina 2014).

Site of collection: Gotari-mot, Seongsan-eup, Seogwipo-si, Jeju-do (April 26, 2018).

Specimen Locality: ACKU2018IR03

Anagnostidinema pseudacutissimum (Geitler) Strunecký, Bohunická, J.R. Johansen and J. Komárek 2017 (Fig. 4)

Synonym:Oscillatoria pseudacutissima Geitler

Phormidium pseudacutissimum (Geitler) Anagnostidis and Komárek 1988

Geitlerinema pseudacutissimum (Geitler) Anagnostidis 1989

The thallus is blue-green colored. Trichomes are straight or slightly coiled and motile with anticlockwise rotation. Trichomes are unconstricted or slightly constricted at crosswalls and slightly attenuated at the ends and bent. Apical cells are hooked and roundly-pointed. Cell contents have prominent carotenoid granules, usually near the cross-walls. Cells are colored bright blue-green and 1.2-3 times longer than wide, with 1.2-1.4 μm width.

Ecology: This species appears in freshwater and benthic habitat (Komárek and Anagnostidis 2005). In this study, we collected it from eutrophic and brackish waterway (salinity 0.2‰).

Distribution: Europe: Netherlands (Veen et al. 2015).

Site of collection: Madong-waterway, Samhyang-eup, Muan-gun, Jeollanam-do (September 1, 2017).

Specimen Locality: ACKU2017IR11

The thallus is fasciculated and blue-green colored. Trichomes are cylindrical and straight, slightly attenuated, sometimes bent at the end. Trichomes are unconstricted or slightly constricted at the cross-walls. Sheaths are facultative hyaline, firm and attached to trichome or wider. Apical cells are strongly or slightly capitate and sometimes with conical calyptra. Hormogonia formation occurred by biconcave necridic cells. Cells are wider than long, length is 2.0- 3.4 μm and width is 4.2-6.5 μm.

Cephalothrix komarekiana C.F.S. Malone et al. 2015 (Fig. 5)

Filaments are cylindrical and straight, but at the end, bent and slightly attenuated. Filaments are constricted or unconstricted at the cross-walls. Sheaths are facultative hyaline, firm and narrow or wide. Hormogonia formation occurred by biconcave necridic cells. At the end of the cells, capitate slightly or strongly appears. Cell contents have facultative aerotopes. Cells are wider than long, length is 1.2-2.5 μm and width is 5.5-7 μm.

Ecology: This species appears in freshwater and benthic habitat. They lives in an alkaline lake in the Brazilian Pantanal wetlands, Mato Grosso do Sul State, Brazil (Malone et al. 2015). In this study, we collected it from brackish small stream (salinity 3.6‰).

Distribution: South America: Brazil (Malone et al. 2015).

Site of collection: Gyeongpo-gyo, Gyeongam-dong, Gunsan- si, Jeollabuk-do (April 29, 2017).

Specimen Locality: ACKU2018IR04

Cells are heteropolar, and solitary or in groups. They are elongated and attached to the substrate by end. The cells are long cylindrical when old. Cell content is homogeneous or with solitary granules, usually with visible, separate chromatoplasma (lateral position of thylakoids). Cells are pale blue-green, olive-green or light reddish colored. Reproduction is occurred by simultaneous or successive from the apex of the cylindrical cells, rarely along the whole cell; division by transverse fission. Exocytes are separated one by one, or a great part cell is transformed into a row of exocytes.

Cyanophanon mirabile Geitler 1955 (Fig. 6)

Cells appear in solitary or in groups. The cells are elongate, cylindrical, straight or arcuated. The apex of the cell is rounded and they divided into a row of cylindrical to barrel-shaped exocytes in the upper parts. Cell contents are usually homogeneous and are pale olive-green, grey-blue or pinkish in color. Cell length is 2.2-4.5 μm and width is 0.7- 1.2 μm.

Ecology: This species occurs in freshwater species and epiphytes on another filamentous algae. They lives on rocks with flowing water, streams and waterfalls with clear, katharobic water, usually in mountains (Komárek and Anagnostidis 2005). We collected it from eutrophic pond.

Distribution: Europe: Czech Republic (Gadea et al. 2013).

Site of collection: Ojo-ri pond, Seongsan-eup, Seogwipo- si, Jeju-do (April 27, 2018).

Specimen Locality: ACKU2018MD04

Family Leptolyngbyaceae Komárek, Kastovsky, Mares and Johansen 2014

Genus Leptolyngbya Anagnostidis and Komárek 1988

Leptolyngbya ectocarpi (Gomont) Anagnostidis and Komárek 1988 (Fig. 7)

Synonym:Phormidium ectocarpi Gomont 1899

Thallus is thin, membranaceous and carmine-red or brownish-red in color. Filaments are densely and irregularly entangled or parallel-arranged. Sheaths are mostly colorless, diffluent, mucilaginous, rarely distinct. Trichomes are constricted at the diaphanous, ungranulated cross-walls and are either slightly attenuated. Apical cells are rounded or conical-rounded, lengthened and without calyptra. Cell contents are homogeneous with distinct chromatoplasma. Cells are isodiametric longer than wide. The length is 1.2-1.5 μm and the width is 1.4-1.7 μm.

Ecology: This species appears in marine and epiphytic, epizoic habitat. They lives epiphytic on various seaweeds, epizoic on various animals, mud and walls of glass vessels with marine water widely distributed in littoral and sublittoral zones of coasts (Komárek and Anagnostidis 2005). We collected it from eutrophic brackish pond (salinity 11‰).

Distribution: Europe: Britain (Whitton et al. 2003), Spain (Gallardo et al. 2016); Indian Ocean Islands: Mauritius (Silva and Pienaar 2000).

Site of collection: Mai-mot, Oedo 2-dong, Jeju-si, Jeju-do (May 19, 2017).

Specimen Locality: ACKU2017IR04

Family Pseudanabaenaceae Anagnostidis and Komárek 1988

Genus Toxifilum Zimba, Huang, Foley and Linton 2017

Filaments are composed of a uniseriate trichome. Sheath is usually present, thin, colorless. Filaments are gliding and attenuated at the end. Cells are longer than wide and they have peripheral thylakoids. Filaments and single cells are bright green colored. Both external and cross cell walls are undulated.

Toxifilum mysidocida Zimba, Huang, Foley and Linton 2017 (Fig. 8)

Filaments are rarely solitary and free floating, usually forming clusters or mats on substrate. Filaments are undulated, with thin sheaths, and are unbranched. Filaments are narrowing at the ends and exhibit gliding motility. Cells are cylindrical, with peripherally arranged thylakoids. Polyphosphate bodies and cyanophycin granules occur in cell corners with micro plasmodesmata present between cross cell walls. Cell’s length is 3-10 μm and width is 2.2-2.5 μm.

Ecology: This species appears in marine and benthic habitat. They lives in Rincon Bayou salt marsh, Nueces Bay, TX, USA (Zimba et al. 2017). We collected it from brackish small stream (salinity 3.6‰).

Distribution: North America: Texas (Zimba et al. 2017).

Site of collection: Gyeongpo-gyo, Gyeongam-dong, Gunsan- si, Jeollabuk-do (April 29, 2017).

Specimen Locality: ACKU2018IR05