Diatom Diversity and First Records from the Chunggulmul Submarine Groundwater Discharge Spring, Jeju Island

다국어 초록 (Multilingual Abstract)

Submarine groundwater discharge (SGD) springs represent dynamic ecotones characterized by the interaction between silica-rich groundwater and coastal seawater; however, the microflora associated with these environments remain inadequately documented in Korea. In this study, we investigated the diatom community within the Chunggulmul SGD spring, where a single mixed water–biofilm sample was subjected to cleaning and subsequent examination using light and scanning electron microscopy (SEM). A total of forty-eight taxa were identified, representing 28 genera, 25 families, 19 orders, and three classes. Notably, five species are newly recorded for South Korea: Amphitetras antediluviana, Entomoneis japonica, Halamphora pseudoholsatica, Halamphora sydowii, and Tryblionella coarctata f. densestriata. In addition, two taxa (Trigonium cf. curvatum and Luticola sp.) could not be assigned to known species and are treated here as taxonomically unresolved.. Diagnostic characters observed using light microscopy and SEM are illustrated and discussed in relation to closely related taxa. This study contributes to the national diatom checklist, provides baseline floristic documentation of diatoms associated with SGD habitats in Korea, and emphasizes the ecological significance of coastal springs such as Chunggulmul as underexplored habitats for diatom diversity. These findings highlight the need for further floristic investigations of groundwater-influenced coastal systems in Korea.