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ISSN : 1226-9999(Print)
ISSN : 2287-7851(Online)
Korean J. Environ. Biol. Vol.42 No.2 pp.158-171
DOI : https://doi.org/10.11626/KJEB.2024.42.2.158

Formal characteristics of an unrecorded freshwater diatom (Bacillariophyceae) in Korea

Daeryul Kwon, Kyeong-Eun Yoo1, Hyunjin Jo2, Chaehong Park2,*
Nakdonggang National Institute of Biological Resources, Sangju 37242, Republic of Korea
1Department of Environmental Health Science, Sanghuh Life Science College, Konkuk University, Seoul 05029, Republic of
Korea
2Encountter the Ecology, Suwon 16512, Republic of Korea
*Corresponding author Chaehong Park Tel. 054-530-0845 E-mail. qkrcoghd2@gmail.com

Contribution to Environmental Biology



▪ Seven new types of diatoms were discovered in freshwater environments in Korea.


▪ The morphology of the specimens was annotated, and their classification was deduced to the genus level.


24/04/2024 01/06/2024 14/06/2024

Abstract


Diatoms, which are reported to have over 18,000 species worldwide and approximately 2,400 species in Korea, can be found in various environments including freshwater, seawater, and wetlands. They are particularly valuable for understanding global environmental changes throughout history due to their ability to maintain their shape for extended periods of time. Instead of collecting floating diatoms using nets, low-layer substrates such as gravel and leaves, as well as sedimentary surface layers, were gathered in order to identify attached diatom species. This is because attached diatoms demonstrate higher species diversity compared to floating diatoms. In this study, seven previously unrecorded diatoms were discovered in various domestic freshwater environments. Two species were found in reservoirs (Eunotia yanomami, Gomphonella pseudookunoi), two in parasitic cones (Eunotia carverenensis, Luticola minor), two in rivers (Cavinula maculata and Prestauroneis integra), and one (Surirella brebissonii var. kuetzingii) in a lagoon. The shapes, structures, and morphological characteristics of each diatom were identified using electron microscopy.


new record diatom , diatom , freshwater , optical microscope , electron microscope

초록

    1. INTRODUCTION

    Diatoms are microalgae, distributed globally and commonly dominate Korean freshwater environments in spring and autumn (Robarts and Zohary 1987;Yu et al. 2014;Yun et al. 2020). They are important primary producers, accounting for ~20% of the total carbon fixation of plants and are considered highly successful organisms in terms of biological evolutionary diversity (Datta et al. 2019).

    Diatoms appear as single cells or colonies without flagella, and ~18,000 diatom species have been identified worldwide (Guiry and Guiry 2024). Approximately 2,260 species have been reported in Korea - known to be the most reported among microalgal taxa with a very high biodiversity (NIBR 2023). Diatoms live or float on water in the presence of substrate such as stone, gravel, or aquatic plants (Barbiero 2000;Salomoni et al. 2006). New diatoms continue to be reported in various modern and fossil fuel sediments (Lee et al. 2020;Park et al. 2021;Kwon et al. 2023).

    Diatoms are extremely useful for understanding changes in the global environment from the past to the present because they can retain their shape for a long time (Lee et al. 2020). Diatoms have a sturdy lid shape, are closed with frustules or thecae (Kröger and Wetherbee 2000;Crawford et al. 2001), and are composed of amorphous silicates that can be easily obtained from natural water (Lewin 1961;Kamatani and Riley 1979). Diatom cells can sink to the lower layers, enabling them to utilize various inorganic nutrients in the lower layers owing to the siliceous, relatively heavy substances occurring there (Smetacek 1985;Riebesell 1989).

    There are two main types of diatoms - pennate and centric (Manton et al. 1969;Lewin and Hellebust 1970). Pennate diatoms exhibit left-right symmetry, typically having a long lid shape with a vertical line or sternum and a protruding vein that is vertically parallel to both ends of the cell, resulting in a hole parallel to the protruding vein, and the lid is decorated in a git shape (Almqvist et al. 2001;Wang et al. 2013). They form a monophyletic group, officially called Bacilliophyceae, and epilithic diatoms mainly fall into this group (Medlin 1991;Ulanova and Snoeijs 2006). Some diatoms have a raphe that allows them to move in a streamlined manner and occupy new habitat types (Medlin 1991). The centric diatom has a radial symmetry of the stria hole arrangement, which is a line shape from the center to the edge of the valve and is mainly a floating diatom (Jewson 1992).

    The seven unrecorded diatoms excavated here were epilithic diatoms - which correspond to pennate diatoms - and included two species in reservoirs (Eunotia yanomami, Gomphonella pseudookunoi), two species in parasitic cones (E. karveerensis, Luticola minor), two species in a river (Cavinula maculata, Prestauroneis integra), and one in a lagoon (Surirella brebissonii var. kuetzsingii). The Eunotia genus includes 698 species worldwide and 72 species in Korea; the Surirella genus includes 306 species worldwide and 38 species in Korea; the Luticola genus includes 271 species worldwide and nine species in Korea; the Cavinula genus includes 29 species worldwide and one species in Korea; the Gomphonella genus and Prestauroneis genus include 42 and 10 species worldwide, respectively; neither of these have yet been reported in Korea (NIBR 2023;Guiry and Guiry 2024). This study aimed to conduct morphological and ultrastructural analyses of excavated diatoms, using optical and electron microscopies not recorded previously.

    2. MATERIALS AND METHODS

    2.1. Sampling sites and methods

    Sampling was conducted at the Geum parasitic cones in Halim-eup, Jeju-do; Naeui Reservoir in Gunwi-gun, Gyeongsangbuk-do, Hoecheon; a river flowing from Goryeong-gun, Gyeongsangbuk-do; Hadong Reservoir in Gyeongju-si, Gyeongsangbuk-do; Imgi-bridge in Gimcheon-si, Gyeongsangbuk-do; and Hwajinpo in Goseong-gun, Gangwon-do (Table 1, Fig. 1). To collect epilithic diatoms, gravel-like substrates were collected from the sampling sites and samples were collected by scraping the diatom and attaching it to the surface of the substrate using a soft brush. The collected samples (100 mL) were fixed by adding 1 mL of Lugol’s solution, stored in an icebox in a sampling bottle, and transported to the laboratory. Water temperature, dissolved oxygen, pH, and electrical conductivity were measured using a portable water quality measuring device (ProDDS; YSI, Yellow Springs, Ohio, USA).

    2.2. Pretreatment for specific identification

    Samples pretreated in the field were placed in a conical tube (SPL Life Science Co., Ltd., Pocheon, Korea), diluted 1 : 1 : 1 with hydrochloric acid and potassium permanganate, placed in a beaker containing distilled water, and heated on a hot plate (SMHS-3; DAIHAN Scientific Wonju, Korea). The mixture was stirred until the color changed from purple to transparent, followed by washing with sufficient distilled water and allowed to stand for 24 h; then, the supernatant was removed. Sample washing was repeated five times using the same method to purify residual reagents and organic matter. After placing a cover glass on the electric heater, 1 mL of the acid-treated sample was dispensed, heated, and dried. Subsequently, one drop of mounting solution (Fujifilm Wako Pure Chemical, Osaka, Japan) was added to the cover glass and covered on the glass slide, which was controlled to spread evenly throughout the sample, and the cover glass was sufficiently pressed to prevent bubbles from occurring. Subsequently, it was sealed using transparent nail polish.

    2.3. Shape and microstructure analysis of unrecorded diatoms

    The shape and size were examined under magnifications of 400 and 1,000 times using a DIC microscope (Differential Interference Contrast Microscope; ECLIPSE Ni-U, Nikon Co., Tokyo, Japan) to analyze the morphological characteristics of the unrecorded diatoms, and image data were obtained using a digital camera connected to the microscope (Nikon DS-Ri2 Camera; Nikon Co., Tokyo, Japan). The length of the long and short axes of the cells was measured using the Innerview 2.0 (Innerview Co., Ltd. 2010, Korea) program. Additionally, the shape was observed and photographed through a field emission scanning electron microscope (Fe-SEM, MIR-3; Tescan, Czech) to view the ultrafine structure not observed with an optical microscope. For the diatom species identification, Lange-Bertalot and Kramer (2000), Kramer (2003), and Watanabe and Yanagisawa (2005) were referenced, and the species name and classification system were organized according to Algaebase (http://www. algaebase. org/). Discrimination of the unrecorded species was confirmed by the status of the name and synonyms in the 2023 National List of Species Korea (NIBR 2023).

    3. RESULTS

    3.1. Phylum Heterokontophyta

    Class Bacillariophyceae

    Order Eunotiales

    Family Eunotiaceae

    Genus Eunotia

    Eunotia karveerensis (H.P.Gandhi)

    A.Glushchenko & M.S.Kulikovskiy 2017

    Basionym.Eunotia camelus var. karveerensisH.P.Gandhi 1957.

    Original description. Gandhi (1957). Freshwater diatoms from Radhanagari, Kolhapur Ceylon Journal of Science (Biological Sciences) 1(1): 45-57.

    Habitat environment.Eunotia karveerensis was discovered in 2012 in samples collected from a paddy field near Cam Ranh Bay, Vietnam (Glushchenko and Kulikovskiy 2017) and was reported by Glushchenko and Kulikovskiy in 2017. No information on the aquatic environment was collected at that time. In this study, it appeared in the Geum parasitic cone, Jeju Island; at that time, the water temperature was 12.9°C, the pH was 7.2, the electrical conductivity was 100.0 μs cm-3, and the dissolved oxygen was 7.6 mg L-1. Therefore, it was confirmed to live in a neutral environment (Fig. 1a, Table 1).

    Description. The valves are strongly convex on the dorsal margins and have four pronounced uniform humps in larger individuals and two to three humps in smaller individuals (Fig. 2a). The ventral margins are strongly concave. Length: 18.5-35 μm, width: 6-7 μm in the humps and 4.5-5.5 μm between the humps. The apices are rounded, subcapitate, and strongly tapered on the dorsal margins, with a width of 2 μm. The nodules at the poles are small. The striae are radial, with 10- 13 in 10 μm on the dorsal margins and 12-14 in 10 μm on the ventral margins. There are 20 areolae in 10 μm. When viewed through an electron microscope, the striae were round, with 11-14 areolae protruding from the central valve and 10-11 areolae in the curved portion. There were two areolae at the valve end, the raphe was obliquely present at the valve end, and the areolae were present on the side of the valve (Fig. 2b-d).

    3.2. Phylum Heterokontophyta

    Class Bacillariophyceae

    Order Naviculales

    Family Diadesmidaceae

    Genus Luticola

    Luticola minor (R.M.Patrick) A.Mayama 1998

    Basionym.Navicula mobiliensis var. minorR.M.Patrick 1959.

    Original description.Patrick, R. (1959). New species and nomenclature changes of Navicula (Bacillariophyceae). Proceedings of the Academy of Natural Sciences of Philadelphia 111: 91-108.

    Habitat environment.Luticola minor was reported by Mayama and Kawashima (1998) in Japan but was unreported at the sampling site and habitat. In this study, it appeared in Geum parasitic cone, Jeju Island; at that time, the water temperature was 12.9°C, the pH was 7.2, the electrical conductivity was 100.0 μs cm-3, and the dissolved oxygen was 7.6 mg L-1. Therefore, it was confirmed to live in a neutral environment (Fig. 1a, Table 1). Description. The valve is close to a round-oval shape and converges toward the end of the valve; therefore, the acidic area is appropriately narrow and of the acupuncture type. The areola is round, and the striae are irregular and dense. The central area is incompletely asymmetrical in the transverse direction, the number of striae in the central area is relatively small, and the number and spacing of striae in the central area narrow toward the apex valve. There is a stigma in the central area, and the raphe shows a form of convergence in the central area (Fig. 3a). When viewed using an electron microscope, the areola was circular, and the irregularity of the striae was more pronounced. The stigma located in the central area had a linear shape, and the asymmetry of the striae in the center was clearly observed (Fig. 3b-d). The areola was not present at the apex valve, and the raphe was bent. Length range: 34- 43 μm, width range: 9-12 μm, striae in LM and SEM were punctate and radiated throughout, 16-20 in 10 μm.

    3.3. Phylum Heterokontophyta

    Class Bacillariophyceae

    Order Eunotiales

    Family Eunotiaceae

    Genus Eunotia

    Eunotia yanomamiMetzeltin & Lange-Bertalot 1998

    Original description.Metzeltin, D. and Lange-Bertalot, H. (1998). Tropical diatoms of South America I. Approximately 700 predominantly rarely known or new taxa representative of Neotropical flora. Iconographia Diatomologica 5: 3-695, 220 pls.

    Habitat environment.Eunotia yanomami was first reported in 1998 after it was isolated from samples collected from the Demera River in Guyana in 1996, and there was no information on the water environment at that time (Metzeltin and Lange-Bertalot 1998). In this study, it appeared in a Naeeui reservoir located in Gumwi-gun, Gyeongsangbuk-do; at that time, it was confirmed that it lived in a strong basic environment, with a water temperature of 5.4°C, pH of 11.5, electrical conductivity of 89 μs cm-3, and dissolved oxygen of 11.3 mg L-1 (Fig. 1b, Table 1).

    Description. The ventral margin of the valve is moderately concave or almost straight. The dorsal edge has two blunt and uniform intervals of undulations that are double-wave-shaped. The apices are blunt. There is a string-of-string radiation, and the areola exists as a punctate. Although it seems to show left-right symmetry, the main feature of this species is that it shows left-right asymmetry around the two blunt and large curves, one side showing a recessed shape and the other with small curves (Fig. 4a). When viewed through an electron microscope, the valve was thicker, there was a raphe at both ends of the valve, and the raphe of approximately 1/4 of the total length was skewed ventrally. The striae were unreiserate, two large curves were also observed when looking at the dorsal side, and asymmetrical grooves and small curves were present from left to right (Fig. 4b-d). Length range: 35-50 μm; width range: 9-13 μm; striae in LM and SEM punctate, radiated throughout, 12-18 in 10 μm.

    3.4. Phylum Heterokontophyta

    Class Bacillariophyceae

    Order Naviculales

    Family Cavinulaceae

    Genus Cavinula

    Cavinula maculata (Bailey) J.Y.Li & Y.Z.Qi, nom. inval. 2018

    Basionym.Stauroneis maculataBailey 1851.

    Original description.Bailey, J. W. (1850). Microscopical observations made in South Carolina, Georgia and Florida. Smithsonian Inst.

    Habitat environment.Cavinula maculate was discovered in 1997 from samples collected near the Toms River in the United States (Cvetkoska et al. 2014). At that time, the collected water environment had a pH of 4.4-5.6 and electrical conductivity of 28-68 μs cm-3. In this study, it appeared in Hoecheon, located in Goryeong- gun, Gyeongsangbuk-do; at that time, the water temperature was 16.6°C, pH was 9.5, electrical conductivity was 109.9 μs cm-3, and dissolved oxygen was 12.7 mg L-1. Therefore, it was confirmed to live in an alkaline environment (Fig. 1c, Table 1).

    Description. The valve has a round arch with an oval shape, showing convergence at the end. The valve face was flat and the mantle was sharply bent at the edge. The striae consist of a radial shape spread based on the central area of the valve. The areola is punctate, and the striae have a regular arrangement. It forms a left-right symmetry with respect to the central area. The raphe is linearly connected from the ends of the left and right valves to the central area. At the end of the raphe (located in the central valve), the central nodule did not have any special areola or decorations, and thick silica was formed (Fig. 5a). When viewed through an electron microscope, these characteristics were observed in more detail, and the regular and dense striae and areolae had a circular shape. The distal end of the raphe had a recessed shape and a thick central nodule was observed. The back of the valve could also be secured using an electron microscope. Unlike the valve, the areola at the end of the valve showed a long linear shape and spread at regular intervals on the edge of the valve (Fig. 5b-d). Length range: 25-41 μm; width range: 15-20 μm; striae in LM and SEM punctate, radiated throughout, 20-25 in 10 μm.

    3.5. Phylum Heterokontophyta

    Class Bacillariophyceae

    Order Cymbellales

    Family Cymbellales incertae

    Genus Gomphonella

    Gomphonella pseudookunoi (Tuji) Tuji 2020

    Basionym.Gomphoneis pseudookunoiA.Tuji 2005.

    Original description.Tuji, A. (2003). Freshwater diatom flora in the bottom sediments of Lake Biwa (Sough Basin): Navicula sensu lato. Bulletin of the National Science Museum. B (Botany) 29: 65-82.

    Habitat environment.Gomphonella pseudookunoi was discovered and reported in 2004 in samples collected from the Arakawa River in Japan; however, there was no information on the aquatic environment collected at that time (Tulji 2005). In this study, it appeared in the Hadong reservoir of Gyeongju, Gyeongsanbuk-do; at that time, the water temperature was 11.0°C, pH was 8.0, electrical conductivity was 121.9 μs cm-3, and dissolved oxygen was 11.3 mg L-1. Therefore, it was con-firmed to live in an alkaline environment (Fig. 1, Table 1). In this study, it appeared in the lower part of Gyeongju, Gyeongsangbuk-do; at that time, the water temperature was 11.0°C, the pH was 8.0, the electrical conductivity was 121.9 μm cm-3, and the dissolved oxygen was 11.3 mg L-1. Therefore, it was confirmed to live in an alkaline environment (Fig. 1d, Table 1).

    Description. The center of the valve was wide, the apex round, and the lower part had a clavate-like shape that narrowed. The axial area was narrow, straight, and widened at the center to form an irregular rectangular central area. Four isolated stigmata were present in the central area, and the raphe formed a straight line that began at the valve end and extended to the central area. The striae exhibited a rib shape, and the striae showed a relatively wide gap in the central area, but becoming denser toward the apex valve (Fig. 6a). When viewed through an electron microscope, the striae showed a striped biserrate and were composed of a small round areola. In contrast, the striae of the genus Gomphonema were lined, as confirmed using an electron microscope. The raphe showed a straight line that became clear and expanded toward the central area of the valve. The central nodule at the valve center was thick, and the four stigmata faced two at the ends of each raphe. Pore fields are observed at the apex of the valve (Fig. 6b-d). Length range: 11-30 μm; width range: 4-7 μm; striae in LM and SEM punctate, radiated throughout, 13-15 in 10 μm.

    3.6. Phylum Heterokontophyta

    Class Bacillariophyceae

    Order Naviculales

    Family Stauroneidaceae

    Genus Prestauroneis

    Prestauroneis integra (W.Smith) Bruder 2008

    Basionym.Pinnularia integraW.Smith 1856.

    Synonym.Navicula integra (W.Smith) Ralfs 1861.

    Original description.Smith, W. (1856). A synopsis of the British Diatomaceæ: with remarks on their structure, functions and distribution, and instructions for collecting and preserving specimens (Vol. 2). Smith and Beck, Pub.

    Habitat environment. Pinnularia integra was found in Silver Lake in Dickinson County, Lowa, with a preference for water with a high mineral content; it is often found in contaminated water (Levkov and Williams 2011). In this study, it appeared at Imgi-bridge, located in Gimcheon, Gyeongsangbuk-do, and was found to live in a neutral environment, with a water temperature of 18.6°C, pH of 7.2, electrical conductivity of 254.7 μs cm-3, and dissolved oxygen of 5.9 mg L-1 (Fig. 1e, Table 1).

    Description. The valve has a blunt central area converging toward the end of the valve. It has two curves and is a needle type. In the central area, the striae have a radial shape parallel to the striae with respect to the central axis and existing until the valve end. In the central area, gaps were observed in relatively wide striae, becoming denser toward the apex. When viewed under an optical microscope, the pseudoseptum - mainly occurring in species such as Gomphonema, Gomphoneis, Stauroneis, and Navicula - is faintly visible at the valve apex. The raphe starts from the valve apex and has a distinct linear shape toward the center area (Fig. 7a). When viewed through an electron microscope, the shape of the valve was round near the center area and lanceolate toward the valve apex, and the nipple was large at the polar nodule. The striae had lines at regular intervals and exhibited a radial shape, showing leftright symmetry. The stria gap in the central area is wide, and the shape narrows toward the valve end. The raphe is a straight line that starts at the valve apex and becomes thicker toward the center. When looking at the gridle, the pseudoseptum was wrapped around the valve in a repand, and there was no apical pore field at the valve apex (Fig. 7b-d). Length range: 26-43 μm, width range: 9-12 μm; striae in LM and SEM punctate; radiate throughout; 10-20 in 10 μm.

    3.7. Phylum Heterokontophyta

    Class Bacillariophyceae

    Order Surirellales

    Family Surirellaceae

    Genus Surirella

    Surirella brebissonii var. kuetzingiiKrammer & Lange-Bertalot 1987

    Original description. Krammer, K. and Lange-Bertalot, H. (1987). Morphology and taxonomy of Surirella ovalis and related taxa. Diatom Research 2(1): 77-95.

    Habitat environment.Surirella brebissonii var. kuetzingii was first reported by Krammer and Lange-Bertalot (1987); however, there was no mention of its collection site or environment at that time. It was later reported in samples collected from the Caspian Sea in southwestern Russia in 2000 (Bulatov 2021). There was no information on the collected water environment at the time, but it is known that the species lives in oceans and brackish water and in environments with high electrolyte content (Dirican et al. 2022). In this study, it appeared in Hwajinpo, located in Goseong-gun, Gangwon- do; at that time, it was confirmed to live in an alkaline environment, with a water temperature of 9.9°C, pH of 8.6, electrical conductivity of 19,200 μs cm-3, and dissolved oxygen of 12.1 mg L-1 (Fig. 1f, Table 1).

    Description. The valve was egg-shaped. The striae originate from the valve center and radiates strongly from the valve apex. In general, the raphe of the genus Surirella is not visible under an optical microscope because it is present on the side of the valve. Around the valve edge, large areolae appear on the optical microscope, but these areolae are actually depressions on the valve surface in the electron microscope, corresponding to the sacrum inside the valve. There appears to be a long line near the valve center, but this line is the protruding part where Porca gathers in the center. Additionally, irregular protrusions were observed in the protruding vein, shown as points on the optical microscope (Fig. 8a). When viewed under an electron microscope, three to four rows of areolae occur between the costae, which can be observed only under an electron microscope. A distinct flat central area was observed on the axial line. The raphe placed along the entire valve margin consisted of four to five lines (Fig. 8b-d). Length range: 43-52 μm; width range: 18-30 μm; striae in LM and SEM punctate, radiating throughout, 18-30 in 10 μm. The striae cannot be viewed with an optical microscope but can be observed with an electron microscope.

    4. DISCUSSION

    The unrecorded diatoms that emerged in this study were simultaneously identified and analyzed to elucidate their morphology and ultrafine structure using optical and electron microscopy. Two species were excavated from the Geum parasitic cone on the Jeju Island, two from reservoirs, two from rivers, and one from a lagoon through the collection of microalgae and water environmental surveys in a domestic freshwater environment over a period of 19 to 21 years. In general, Eunotia occur in wetlands or reservoirs at relatively shallow depths (Pavlov and Levkov 2013). Both E. karverenensis and E. yanomami mentioned here were found at low water elevations and in reservoirs. Since E. karverenensis was first reported in 2017, there has been little information on this species, and while there are image data from an optical microscope for E. karverenensis in the existing literature, this is the first study to analyze an ultrafine structure using an electron microscope. Luticola minor is a freshwater species that mainly emerges from rivers or lakes, and is often found in aerobic habitats (Mayama and Kawashima 1998). In this study, it was also found in dissolved oxygen of 7.6 mg L-1 and confirmed that it appeared in a habitat environment similar to other study. It has a similar shape to L. submobiliensis but differs in valve length-to-width ratio in each taxon (Witkowski et al. 2019). The genus Luticola was previously named Navicula, but Mann decided to follow the genus name of Luticola in 1990. Cavinula maculata mainly lives in weakly acidic and low-permeable environments (Cvetkoska et al. 2014). In the Hoecheon river, it was collected in a weakly alkaline environment at that time and but can live in both weakly acidic and alkaline environments. The genus Cavinula was previously named Stauroneis, but it was changed by Bahls in 2013. The genus Gomponella has a wedge shape, similar to that of Gomponema. The striae of the genus Gomponema are uniseriate, but that of the genus Gomponella are biseriate; the genera Gomponema and Gomponella cannot be distinguished by a general optical microscope and require resolution using an electron microscope. Prestauroneis integra was previously used in the genera Pinnularia and Navicula, but was changed to a formal genus name by Bruder and Medlin in 2008. A major feature of the genus Prestauroneis is the presence of pseudoseptae, which can be observed under optical and electron microscopes. The genus Surirella is commonly found in freshwater environments, particularly in low-layer substrates and sedimentary surface layers (Belanger et al. 1985;Bramburger et al. 2006). The genus Surirella has higher motility than other diatoms owing to its extensive raphe system located around the valve and can live in sand or microscopic sediments (Ruck and Theriot 2011). The S. brebisonii var. kuetzingii found here is known to live mainly in brackish waters with high electrical conductivity (Szczepocka et al. 2019). It also appears in lagoons with high electrical conductivity, and is judged to prefer a high electrical conductivity environment. As countries worldwide recognize the importance and value of biological resources and conduct various studies to secure and utilize their own biological resources, it is necessary to explore the native organisms distributed in Korea and establish national biological sovereignty using confirmatory information of the reported species.

    ACKNOWLEDGEMENTS

    This work was supported by grant from the Nakdonggang National Institute of Biological Resources (NNIBR 20241104).

    CRediT authorship contribution statement

    DR Kwon: Conceptualization, Methodology, Formal analysis, Investigation, Validation, Resources, Writing- Original draft, review and edition, Funding acquisition, Supervision, Project administration. KE Yoo: Investigation, Resources, Writing-Original draft, review and edition. HJ Jo: Validation, Resources, Writing-Original Draft, review and edition. CH Park: Conceptualization, Methodology, Formal analysis, Writing-Original draft, review and edition, Supervision, Project administration.

    Declaration of Competing Interest

    The authors declare no conflicts of interest.

    Figure

    KJEB-42-2-158_F1.gif

    Sampling sites for diatom collection.

    KJEB-42-2-158_F2.gif

    Morphology of Eunotia karverenensis observed through an optical microscope (a), and the hyperfine structure (b-d) of E. karverenensis observed through an electron microscope.

    KJEB-42-2-158_F3.gif

    Morphology of Luticola minor observed through an optical microscope (a), and the hyperfine structure (b-d) of L. minor observed through an electron microscope.

    KJEB-42-2-158_F4.gif

    Morphology of Eunotia yanomami observed through an optical microscope (a), and the hyperfine structure (b-d) of E. yanomami observed through an electron microscope.

    KJEB-42-2-158_F5.gif

    Morphology of Cavinula maculata observed through an optical microscope (a), and the hyperfine structure (b-d) of C. maculata observed through an electron microscope.

    KJEB-42-2-158_F6.gif

    Morphology of Gomphonella okunoi observed through an optical microscope (a), and the hyperfine structure (b-d) of G. okunoi observed through an electron microscope.

    KJEB-42-2-158_F7.gif

    Morphology of Prestauroneis integra observed through an optical microscope (a), and the hyperfine structure (b-d) of P. integra observed through an electron microscope.

    KJEB-42-2-158_F8.gif

    Morphology of Surirella brebissonii var. kuetzsingii observed through an optical microscope (a), and the hyperfine structure (b-d) of S. brebissonii var. kuetzsingii observed through an electron microscope.

    Table

    Information on sampling sites and environmental factors

    Reference

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    Vol. 40 No. 4 (2022.12)

    Journal Abbreviation 'Korean J. Environ. Biol.'
    Frequency quarterly
    Doi Prefix 10.11626/KJEB.
    Year of Launching 1983
    Publisher Korean Society of Environmental Biology
    Indexed/Tracked/Covered By

    Contact info

    Any inquiries concerning Journal (all manuscripts, reviews, and notes) should be addressed to the managing editor of the Korean Society of Environmental Biology. Yongeun Kim,
    Korea University, Seoul 02841, Korea.
    E-mail: kyezzz@korea.ac.kr /
    Tel: +82-2-3290-3496 / +82-10-9516-1611