Search Results (46)

As climate change intensifies, assessing vulnerability at territorial levels such as cities, countries, and regions is essential for effective adaptation planning. This study evaluates the applicability of the United Nations Environment Programme and South Pacific Applied Geoscience Commission’s Environmental Vulnerability Index (EVI) for coastal regions in South Korea. By adapting and localizing 50 international indicators and a Geographic Information System framework, this research developed a Korean Coastal Vulnerability Index and used spatial regression analysis to compare results to historical water-related disaster data from 2010 to 2019. The findings reveal that contrary to South Korea’s global classification of “extremely vulnerable”, most coastal counties appear relatively resilient when viewed through the localized model. Sub-index analyses indicate that ecological and anthropogenic damage factors show the strongest correlation with past disasters among the hazard, resistance, and damage categories. While the model’s explanatory power was modest (R² = 0.017), the regression nonetheless provides meaningful insight into how global indices can reflect local vulnerability patterns. The regression results confirm that based on historical hazard records, the international model effectively predicts Korean coastal vulnerability. It demonstrates the potential of scaling down global models to fit national contexts, offering a replicable approach for countries lacking localized vulnerability frameworks. It advances climate adaptation research through methodological innovation, policy-relevant spatial analysis, and theoretical insights into the multidimensional nature of vulnerability. The results support more precise, data-driven resilience planning and promote international collaboration in climate risk management. Full article

Canopy-forming algae play an important role in coastal ecosystems because these species are highly productive and provide habitats and shelter for numerous marine organisms. Sargassum is the main genus of canopy-forming algae in the western North Pacific, but despite the importance of their ecological role, studies on the changes in their distribution are still scarce. Based on the present distribution of four Sargassum species, this study predicted the geographic distribution of future habitats (2030s, 2060s, and 2090s) under three Shared Socioeconomic Pathway (SSP) scenarios. The environmental variables predicted from the sixth phase of the coupled model intercomparison project (CMIP6) had different impacts depending on the species, with current velocity and water temperature showing high contributions in all four species. According to the projections, three Sargassum species (S. horneri, S. macrocarpum, and S. patens) are expected to maintain a higher habitat suitability index (HSI) and suitable habitat (MAXENT ≥ 0.4) through the 2090s under the SSP1-1.9 scenario. However, under the SSP2-4.5 and SSP5-8.5 scenarios, the HSI of the species is projected to gradually decrease in the southern coastal waters of the Korean peninsula and increase in the East Sea (North Korea), with these results intensifying under the SSP5-8.5 scenario. On the other hand, S. piluliferum was found to increase its HSI and habitat under the highest emission scenarios. All Sargassum species are predicted to shift northward from 0.8° N to 3.8° N by the 2090s under the SSP5-8.5 scenario. Although many marine protected areas exist off the coasts of South Korea and Japan, suitable Sargassum habitats were found to be located within protected reserves between 47.1% and 61.2%, depending on the scenario. These findings on Sargassum provide distributional predictions for ecological conservation strategies and provide new evidence for the need for climate change efforts. Full article

The offshore transport of coastal water masses in the East China Sea is vital for maintaining ecological stability. Understanding its spatial-temporal pathways helps clarify material transport and ecological responses. This study used total suspended sediment (TSS) data from the Korean Geostationary Ocean Color Imager to analyze TSS distribution and anomalies, combined with satellite-derived surface residual currents. Results show significant seasonal variations: coastal water masses expand to the 50 m isobath in winter and contract to the 20 m isobath in summer. Offshore transport pathways vary spatially, extending to the shelf edge north of 28° N but restricted by the Taiwan Warm Current south of 28° N. A persistent transport pathway near 28° N shifts from northeastward to eastward. Other pathways include one south of Hangzhou Bay (spring and autumn) linked to tidal mixing and another north of the Yangtze River estuary (summer) following the Yangtze River Diluted Water. These findings provide crucial observational insights for modeling material cycling in the East China Sea shelf. Full article

Rainfall-induced freshwater influx is a major nutrient source in estuarine and coastal waters, often driving changes in phytoplankton community structure and blooms. In Jinhae Bay of Korea, a critical area for shellfish aquaculture, the interaction between the Nakdong River discharge and the Tsushima Warm Current creates a frontal zone conducive to phytoplankton proliferation. This study investigated the seasonal variation in phytoplankton communities, including harmful and toxin-producing species, in relation to environmental factors from February 2022 to November 2023 in Jinhae Bay. Except for the summer increase in certain dinoflagellates, diatoms, including Chaetoceros spp., Pseudo-nitzschia spp., and Skeletonema spp., dominated the phytoplankton community across seasons. In addition, nutrient influx from the Nakdong River, particularly nitrate + nitrite and silicate (p < 0.001), was a key driver of phytoplankton community structure. Spatially, phytoplankton communities differed between the inner (St. 1 and 4) and outer (St. 2 and 3) areas in the bay, likely due to the influences of seasonal river discharge, the Tsushima Warm Current, and tidal currents. Among harmful algal blooms causative species, dinoflagellate Margalefidnium polykrikoides was correlated with water temperature, exhibiting higher densities in summer. In contrast, Akashiwo sanguinea was mainly observed in winter. In addition, we found that toxin-producing dinoflagellates, such as Alexandrium catenella, Dinophysis acuminata, and Gonyaulax spinifera, were most prevalent in spring and summer, and their appearance was linked to complex interactions among freshwater influx, water temperature, and current dynamics. Our findings underscore the critical role of bay-specific oceanographic conditions, shaped by tidal and current patterns, in conjunction with riverine nutrient inputs, in driving seasonal phytoplankton blooms. This study provides valuable baseline data for understanding harmful/toxic microalgal dynamics in Jinhae Bay and offers key insights for effective coastal ecosystem management and conservation along the Korean Peninsula. Full article

Scomber japonicus, commonly known as chub mackerel, is a fish species of economic significance in Korea, China, and Japan, whose natural abundance has reduced dramatically due to overfishing and environmental changes. To investigate the genetic differentiation and population structure of S. japonicus, a 359 base pair segment of the mitochondrial DNA (mtDNA) control region sequence was analyzed in 96 individuals sampled from three locations in Korean waters. Sixty-six haplotypes were recognized, of which 61 (92.42%) were population specific, whereas only five haplotypes were shared by multiple populations (8%). Two clades were revealed with low support values, and no specific genealogical branches were recognized according to geographical locations. Significant genetic differentiations, however, were detected among the three populations, with F_ST values (p < 0.05). These results indicate that populations of S. japonicus in Korean waters are genetically subdivided. Migration patterns, spawning site fidelity, and current temperature could be the possible causes of this subdivision. Consequently, it is thought that each of the genetically unique S. japonicus stocks found in Korean waters requires a different approach to management. Full article

Microplastic distribution surveys centered on Korea’s Gwangyang Bay and southern coastal waters. Gwangyang Bay seawater averaged 3.17 ± 1.23 particles/L, and sediments averaged 462.4 ± 143.9 particles/kg. The southern coastal seawater averaged 0.10 ± 0.09 particles/L, and the sediments averaged 50.6 ± 29.7 particles/kg. Microplastics flowing from land, through physical modeling of ocean currents in Gwangyang Bay and southern coastal waters, pass through the Yeosu Strait and flow into the southern coastal waters. At the same time, it is judged that the southern coastal waters showed somewhat lower abundance than the Gwangyang Bay waters because they move toward the Korean Strait due to the Jeju warm current water and Tsushima current water, strongly generated in summer. In addition, the seawater microplastic abundance showed a higher abundance than that on the site adjacent to the land in the southern coastal waters, which is the study area. On the other hand, the results for sediment microplastic abundance were opposite to the surface seawater microplastic results. Therefore, it is judged that entering one source of pollution does not affect the distribution of microplastics in Gwangyang Bay and southern coastal waters, but rather this occurs in different forms. Full article

The seasonal dynamics of phytoplankton communities in Korean coastal waters (KCWs) are influenced by complex interactions between ocean currents and nearshore human activities. Despite these influences, the understanding of seasonal phytoplankton changes and their environmental relationships in KCWs remains limited. We investigate the influence of the distinct characteristics of the three seas surrounding the KCWs (the Yellow Sea, the South Sea, and the East Sea) on seasonal phytoplankton communities based on field surveys conducted at 23 stations between 2020 and 2021. The East Sea exhibited higher winter temperatures due to the Jeju and Tsushima warm currents, while summer temperatures were lower compared to the other regions, highlighting the role of currents and deeper oceanic waters. The Yellow Sea showed significant freshwater influence with low salinity levels from major rivers, contrasting with the higher salinity in the East Sea. These differences led to a disparity in the productivity of the two regions: the highest value of Chl. a was observed to be 6.05 µg L⁻¹ in the Yellow Sea in summer. Diatoms dominated in nutrient-rich conditions, particularly in the Yellow Sea, where they comprised up to 80–100% of the phytoplankton community in summer, winter, and spring. PCA analysis revealed positive correlations between diatoms and Chl. a, while cryptophytes, which thrive in the absence of diatom proliferation, showed no such correlation, indicating their opportunistic growth in nutrient-limited conditions. This study highlights the significant impact of region-specific hydrographic factors on phytoplankton communities in KCWs, with diatoms dominating in summer and cryptophytes and dinoflagellates showing seasonal and regional variations. Understanding these dynamics is crucial for predicting phytoplankton bloom dynamics and their ecological implications in coastal ecosystems. Full article

In recent decades, eutrophication in inland and coastal waters (ICWs) has increased due to anthropogenic activities and global warming, thus requiring timely monitoring. Compared with traditional sampling and laboratory analysis methods, satellite remote sensing technology can provide macro-scale, low-cost, and near real-time water quality monitoring services. The Geostationary Ocean Color Imager (GOCI), aboard the Communication Ocean and Meteorological Satellite (COMS) from the Republic of Korea, marked a significant milestone as the world’s inaugural geostationary ocean color observation satellite. Its operational tenure spanned from 1 April 2011 to 31 March 2021. Over ten years, the GOCI has observed oceans, coastal waters, and inland waters within its 2500 km × 2500 km target area centered on the Korean Peninsula. The most attractive feature of the GOCI, compared with other commonly used water color sensors, was its high temporal resolution (1 h, eight times daily from 0 UTC to 7 UTC), providing an opportunity to monitor ICWs, where their water quality can undergo significant changes within a day. This study aims to comprehensively review GOCI features and applications in ICWs, analyzing progress in atmospheric correction algorithms and water quality monitoring. Analyzing 123 articles from the Web of Science and China National Knowledge Infrastructure (CNKI) through a bibliometric quantitative approach, we examined the GOCI’s strength and performance with different processing methods. These articles reveal that the GOCI played an essential role in monitoring the ecological health of ICWs in its observation coverage (2500 km × 2500 km) in East Asia. The GOCI has led the way to a new era of geostationary ocean satellites, providing new technical means for monitoring water quality in oceans, coastal zones, and inland lakes. We also discuss the challenges encountered by Geostationary Ocean Color Sensors in monitoring water quality and provide suggestions for future Geostationary Ocean Color Sensors to better monitor the ICWs. Full article

This study assessed the taxonomic statuses of three lesser-known Magelona F. Müller, 1858 species collected from intertidal to sublittoral habitats in Korean coastal waters, basing identification on morphological features and comparing them with their closest congeners. We present a comprehensive description and illustration of taxonomically significant and standardized characters, covering all thoracic chaetigers of three newly discovered Magelona species from Korea. Within the documented Korean Magelona species, these three species exhibit the following distinctive characteristics. Magelona sachalinensis Buzhinskaja, 1985, possess diminutive superior dorsal lobes in the initial four chaetigers and specialized chaetae on chaetiger 9; Magelona lenticulata Gallardo, 1968, is characterized by foliaceous postchaetal superior dorsal lobes in chaetigers 1–8; and Magelona cf. longicornis Johnson, 1901, is distinguished by notably elongated noto- and neuropodial postchaetal lamellae on chaetiger 9. Methyl green staining patterns showed species-specific characteristics and were confirmed to be effective in distinguishing the examined Korean species from each other and useful for making comparisons with previously reported Magelona species. Our study suggests that further comprehensive research on the morphological and genetic characteristics of Magelona species will enhance our understanding of their diversity. Full article

Microalgae are highly valued for their rapid biomass production and metabolite synthesis, as well as their abundance of beneficial compounds. They have a variety of applications, including serving as the primary ingredient in biofuels, functional foods, and cosmetics. The genus Picochlorum, which was established to represent the unique characteristics of “Nannochloris-like” algae, exhibits rapid growth and a high salt tolerance. The morphology, molecular phylogeny, and fatty acid composition of an unspecified Picochlorum strain KCTC AG61293 found in Korean coastal waters were investigated. The strain exhibited a unique cell morphology and reproduction type compared to other Picochlorum species, as determined using light microscopy, fluorescence microscopy, and field emission scanning electron microscopy (FE-SEM). The vegetative cells were elongated and cylindrical in shape, underwent binary fission, and possessed a parietal chloroplast. A molecular phylogenetic analysis using nuclear small subunit ribosomal RNA sequences showed that Picochlorum sp. (KCTC AG61293) belongs to the Picochlorum clade and is closely related to the genus Nannochloris. Compared to other reference species, Picochlorum sp. (KCTC AG61293) had higher levels of saturated fatty acids (SFAs) and alpha-linolenic acid (ALA). The increased levels of SFAs and ALA suggest that Picochlorum sp. (KCTC AG61293) may be a promising candidate for biofuel production and other industrial uses. Full article

Ascidiella aspersa, originally native to the northeastern Atlantic, has emerged as a prolific invasive species in coastal waters worldwide. In 2010, it was identified as an alien species in Republic of Korea, rapidly colonizing artificial harbor structures and outcompeting native species. This study employs morphological analyses and genetic sequencing, focusing on mitochondrial DNA (cytochrome oxidase subunit I; mt-COI) and nuclear markers (18S rRNA), to unravel the genetic structure and haplotype diversity (Hd) of A. aspersa populations in Republic of Korea and globally. The analysis of 154 mt-COI and 127 18S rDNA global population sequences, as well as 80 mt-COI and 79 18S-rDNA Korean population sequences, revealed distinct genetic patterns. Among global populations, the mt-COI gene displayed significant genetic diversity, with 21 distinct haplotypes distributed across 41 polymorphic sites, which is indicative of extensive genetic variability. In contrast, the 18S rDNA marker exhibited limited diversity, with only four haplotypes identified at three polymorphic sites. In Korean populations, the mt-COI gene also exhibited substantial genetic diversity, with 14 distinct haplotypes displaying genetic variations at 29 polymorphic sites. Conversely, the 18S rDNA marker in Korean populations revealed a unique genetic pattern, with only one shared haplotype. These findings emphasize the complex genetic diversity within A. aspersa populations, both globally and in Republic of Korea. This genetic analysis provides valuable insights into the species’ colonization history and adaptation mechanisms, shedding light on the factors shaping its genetic structure. Further research is warranted to elucidate the ecological implications of these genetic patterns in the context of invasion biology. Full article

The majority of marine debris is found in shallow waters; however, submerged debris accumulated at the sea bottom is affected by this kind of pollution. To mitigate the harmful effect of marine debris, we have to recognize its characteristics. However, it is hard to estimate the quantity of submerged marine debris because the monitoring of submerged marine debris requires greater cost and time compared to the monitoring of beach or coastal debris. In this study, we used the data for submerged marine debris surveyed in the sea near the Korean Peninsula from 2017 to 2020 and the data of fishing vessels passing through the areas from 2018 to 2020. In addition, the correlation of major factors affecting the amount of submerged marine debris was analyzed based on the fishing vessel data and the removal project data for submerged marine debris. Moreover, we estimated the amount of submerged marine debris based on the fishing vessels at the collection sites surveyed two or more times using a stepwise regression model. The average amount of submerged marine debris estimated by the model was 6.0 tonnes more than that by the removal project, for which the error was ~26.5% compared to the amount collected by the removal project. The estimation method for submerged marine debris developed in this study can provide crucial information for an effective collection project by suggesting areas that require a collection project for submerged marine debris based on the information of fishing vessels. Full article

The common dolphin (Delphinus delphis) is the second-most bycaught species in Korean waters. To provide key information about their habitat boundaries and hotspots for spatial conservation and management, the spatial use of this species was examined using data obtained from sighting and bycatch surveys of cetaceans in the past 20 years. The 95% minimum convex polygon and 95% density contour of fixed-kernel analysis suggested that the boundary of the home range of common dolphins is limited to the coastal region (Busan–Sokcho) of the East Sea/Sea of Japan. From 50% density contours drawn by kernel density estimation, it was suggested that their hotspots are around the coast of Ulsan–Pohang, Doghae, and Sokcho within the home range. Common dolphins were not observed in the Yellow Sea. Hence, shallow waters in the geographic area of the coastal region of the Yellow Sea are likely not a suitable habitat for common dolphins in this region. Full article

Species of the marine dinoflagellate genus Karenia are known to produce various potent biotoxins and can form noxious blooms that cause mass mortalities of fish and shellfish. To date, harmful blooms of the species K. mikimotoi have been reported in Korea, but K. papilionacea was recently recorded off the southern coast of Korea. Here, we developed a quantitative real-time PCR (qRT-PCR) assay with specific primer pairs for the accurate detection and quantification of these two similar-looking unarmored species, K. mikimotoi and K. papilionacea, and investigated their distribution and dynamics in Korean coastal waters. Overall, K. papilionacea had not only a wider distribution, but also higher cell abundances (15–2553 cells L⁻¹) than K. mikimotoi (3–122 cells L⁻¹) in surface waters. Of 18 sampling sites, the two Karenia species were found to coexist at two sites. During monitoring at a fixed station (S5), K. papilionacea was generally predominant over K. mikimotoi; however, the two species exhibited similar dynamics and occasionally co-occurred. Both Karenia species showed similar physiological responses to temperature and salinity, requiring similar conditions for optimum growth. These results suggest that blooms of the two species may co-occur and induce a synergistic adverse effect on marine environments. Full article

To investigate the factors affecting water quality in coastal regions with sea dike constructions, surface water outside a sea dike was monitored for six years from 2015 to 2020 in the Saemangeum region of Korea. Statistical analyses of the six years of high-frequency measurements revealed that the water quality in this system was predominantly governed by natural processes followed by pollutant inputs as the secondary influencing factor. Severe dissolved oxygen (DO) depletion was observed in the surface waters during warm periods, probably owing to the advection of DO-depleted water from elsewhere to the surface layer. Based on the apparent oxygen utilization (AOU)–pH relationship (r = 0.52, n = 1837), the maximum AOU (180 µM) led to a pH decrease from 8.04 to 7.50, which was considerably lower than the estimated value of 7.72. This extra pH drop was probably due to a reduction in the buffering capacity associated with increased CO₂ in the water column originating from the atmosphere and in situ production, as well as local water column redox reactions associated with benthic inputs of reduced chemical species. Overall, persistent DO depletion with ongoing eutrophication/hypoxia could accelerate ocean acidification in Korean coastal waters, which could be more acute in coastal regions with artificial coastal constructions. Full article