Won Kim's research while affiliated with Seoul National University and other places

The coastline of the Korean Peninsula is influenced by three major oceanographic ecoregions, including the estuarine Yellow Sea ecoregion on the west coast, the warmer and saline East China Sea ecoregion on the south coast, and the cold East Sea ecoregion on the east coast. The influence of these marine ecoregions on the distribution of intertidal barnacles has not been extensively studied. The present study examines the biogeography of thoracican barnacles from intertidal and shallow subtidal zones, along the coasts of Korea. Twenty-one species in seven families were identified, including three species of coral-associated barnacles. Species composition varied significantly in the three marine ecoregions. Multivariate analysis showed barnacle assemblages were significant among the three ecoregions, although there are large overlaps of clusters between the Yellow Sea and East China Sea ecoregions. The estuarine species, Fistulobalanus albicostatus , occurred mainly in the Yellow Sea ecoregion; warm-water species, Tetraclita japonica , and sponge inhabiting barnacles Euacasta dofleini were observed in the East China Sea ecoregion; and cold-water species, Balanus rostratus and Perforatus perforatus , were found in the East Sea ecoregion. Four invasive barnacle species were recorded and the European barnacle Perforatus perforatus expanded its range northward from its recorded distribution nine years earlier. The cold-water species, Chthamalus dalli and Semibalanus cariosus , previously recorded in the East Sea ecoregion, were absent in the present survey. A trend of increasing seawater temperatures in Korean waters may have a significant impact on the distribution of cold-water species and enhance the northward invasion of P . perforatus .

The sea spider genus Cilunculus Loman, 1908 comprises 33 species having short chelifores, separate lateral processes, and a hood structure on the cephalic segment. A pycnogonid species, Cilunculus armatus (Böhm, 1879), was collected from Baekdo Island and Chujado Island, Korea. This species is characterized by having a hood structure on the cephalic segment, separate lateral processes, a low ocular tubercle without eyes, and 3-segmented chelifores. In the examined material, chela shape, arrangement of compound spines on strigilis, and number of heel spines at propodus were different from the previous literatures. Here, we examined C. armatus collected in Korean waters and provided illustrations and pictures in detail.

The complete mitochondrial genome of Chionoecetes opilio is a 16,067 bp long, circular molecule which contains 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and 2 ribosomal RNA genes (rRNAs). Its gene contents and organization are generally similar to other majoid mitogenomes. However, the mitogenome shows unique characteristics; long terminal amino acids, loss or addition of 3 PCGs, a 1216 bp long putative D-loop region, and peculiar secondary structures of 5 tRNAs. The concatenated amino acid sequences of 13 PCGs were used to analyze the phylogenetic tree, which well supported the monophyly of brachyuran clades of Majoidea, Heterotremata, Thoracotremata, and Eubrachyura.

Zooplankton communities are useful bioindicators that can provide information on the changes occurring in marine ecosystems. Therefore, investigation of zooplankton communities in marine and coastal national parks is essential. However, the surveys of zooplankton communities using morphological identification require considerable time and labor. Metabarcoding is a practical alternative that can detect various taxa simultaneously. In this study, metabarcoding was newly applied along with the traditional morphological identification to establish a method for zooplankton community survey in the Marine and Coastal National Park areas of Korea. By comparing the results of these two identification methods, the strengths and limitations of metabarcoding were verified with the zooplankton communities appearing in these areas. The sensitive detection capability of metabarcoding enabled the identification of potential bioindicator taxa associated with external factors (e.g., water temperature, salinity, topography, and chlorophyll a concentration) in these national parks. We propose the use of metabarcoding for efficient surveys of mesozooplankton communities in the Marine and Coastal National Parks to establish monitoring of bioindicator taxa. It is also necessary to continuously search for taxa with high research value in these national parks using metabarcoding. Establishing an ongoing monitoring system that employs this approach can provide an effective tool for managing marine ecosystems in the Marine and Coastal National Parks.

Two species of the family Majidae, Sakaija japonica (Rathbun, 1932) and Schizophroida simodaensis Sakai, 1933, are herein newly reported from Korean waters. These are also the first records of Sakaija Ng & Richer de Forges, 2015 and Schizophroida Griffin & Tranter, 1986 in Korea. There are currently 14 majoid species from nine genera in Korea. Herein, diagnoses of Sakaija japonica and Schizophroida simodaensis are provided together with illustrations.

We report the discovery of a new species of the genus Pycnogonum Brünnich, 1764 found in the shallow waters of Green Island, Taiwan. Pycnogonum (Nulloviger) granulatum sp. nov. is characterized by the presence of the granular integument, a dorsal tubercle on the proboscis, the transverse ridges on the dorsal surface of the trunk, and the spines on the ventral surface of the tibia, tarsus, and propodus having cleft tips. Because the male gonopores are present and ovigers are absent, the present species belongs to the subgenus Nulloviger. The present species has been compared with P. (N.) moolenbeeki Stock, 1992, P. (N.) lobipes Stock, 1991, P. (N.) tuberculatum Clark, 1963, P. nodulosum Döhrn, 1881, and P. spatium Takahashi, Dick & Mawatari, 2007. Among the congeners, P. spatium is geographically the closest congener, of which type locality is Amami Island, Japan. The holotype of P. spatium was loaned from Hokkaido University Museum (ICHUM) and re–examined. To determine the exact gender of the holotype of P. spatium, additional investigations of the coxal pellicula and gonopores are required.

The solitary ascidian, Ciona savignyi (Ascidiacea, Enterogona) is a notorious marine invader still expanding its habitat range worldwide. This species is considered native to the North West Pacific, but its indigeneity in Korean coastal waters has been questioned because of outdated taxonomic records and its inhabitation of oceanographically marginal areas. To clarify their cryptic invasion state, 247 individual C. savignyi samples were collected from 12 harbors and marinas on the Korean coast, and a 744 bp region of mitochondrial DNA (mtDNA) cytochrome c oxidase subunit I gene was sequenced and analyzed. Our analyses of population genetic structure and demographic history provided considerable pieces of evidence supporting their long-term establishment on the Korean coasts: differentiated population genetic structure, sequentially arrayed star-shape haplotype network, neutrality test results of past population expansions, and post-glacial colonization pattern of demography. Consequently, we concluded that C. savignyi populations on the Korean Coast are indigenous rather than exotic. These results could be used as reference data for further phylogeographic and demographic studies of problematic Ciona species, and to clarify and resolve similar cryptic invasion states of the other Korean coastal marine organisms. This study is the first to resolve the cryptic invasion state of Korean marine organisms using genetic analysis.