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The genus Fogedia was first established in 1997 based on Navicula giffeniana as a type species. The important features of the genus were the presence of lateral area, the location of the internal raphe fissure, and the simple apical raphe endings. Later, the generic description of Fogedia has been emended with the reports of four new species to the science having the genus to include twelve members in total. A thirteenth member of the genus has been observed in tidal flats of the Yellow Sea, and here we describe the species as Fogedia orientalis sp. nov. based on observations with the light (LM) and scanning electron microscope (SEM). Regional distribution of the species in the Northeast Asia is also discussed. The new Fogedia species is morphologically similar to F. densa in terms of small cell size as wells as the absence of a lateral area, however, the density and pattern of striae are clearly different from each other. Morphological characteristics and global occurrences of the thirteen Fogedia species has been provided.

Late Holocene diatoms were identified from four sediment cores from the Gonggeomji Wetland in Korea. In total, 52 diatom species belonging to three classes, 21 families, and 29 genera were investig...

In this study, tidal stream energy resources of the Southwestern Sea of Korea were assessed using a numerical model, Modelo Hidrodinâmico (MOHID). This numerical model is based on the finite volume method, which allows numerical experiments on estuaries, coasts, and oceans. For the numerical experiment, we used grid data of at least 90 m resolution by applying bathymetry data created by the Korea Institute of Ocean Science & Technology (KIOST) and FES2012 data as a tidal boundary condition. Strong tidal currents occur in the Southwestern Sea of Korea due to the characteristics of the tidal systems of the West Sea and the South Sea, and the topographical characteristics of a Ria coast. These characteristics were appropriately reproduced by the numerical experiment. Accordingly, the average and maximum tidal currents calculated by the numerical model were used in the assessment. Two regions, Jangjuk and Maenggol-Geocha, were selected as the candidate areas for tidal stream energy development. In addition, the amounts of tidal stream energy resources were evaluated using geographical information system-based spatial analysis by applying the tidal current, depth data, and area of each region. The resource amounts were estimated to be 4,841 MW, with 5,743 tidal stream energy converters (TECs) for Jangjuk, and 3,497 MW, with 3,676 TECs for Maenggol-Geocha.

The study aimed to understand the forest structure and ecological factors influencing mangrove distribution in eight mangrove forests across three climatic zones in Sri Lanka. We studied mangrove diversity and vegetation structure with 10m wide belt transects laid of different lengths (n=96) across the land-water gradient. Mangroves along the transect were identified, enumerated, and measured diameter at breast height (DBH). Subsurface water samples were taken in the adjoining lagoon/estuary to assess the environmental parameters (n=144), and water quality parameters were measured. Site-dependent spatial changes in the community structure were depicted through cluster analysis (CA). The forest survey revealed a heterogeneous mixture of 20 true mangrove species across the sites dominated by Avicennia, Rhizophora, and Sonneratia spp. Among the several environmental parameters analyzed by the distance-based redundancy ordination analysis (dbRDA), salinity, dissolved oxygen, and precipitation were found to be controlling factors in mangrove community structure. In addition, discriminant analysis confirmed the presence of ecological-phytosociological influence on mangrove assemblages identified through CA. The significant structural parameters tree density, and taxonomic diversity when tested using the canonical analysis of principal coordinates (CAP), altered the species abundance across the sites surveyed. The results suggest that there is a strong linkage between phytosociology and ecology with the mangrove forest distribution and this relationship needs to be considered wisely to fortify successful restoration practices.

The west coast of South Korea is characterized by a wide macrotidal area with a maximum tidal range of ∼10 m. The sea surface elevation varies with the tidal phase, which leads to significant changes in the vertical structure of the physical, chemical, and biological properties of the water column, especially when the interaction by waves and/or the freshwater and sediment input from the river increases. Under such conditions, it is difficult to carry out continuous and consistent measurements of the vertical structures of the water qualities using a conventional observation system that is fixed to the seabed or sea surface because the thickness of the water column constantly changes. Based on the demand for long-term observations of the vertical structures of the water properties in macrotidal environments, the Intelligent Buoy System (INBUS) was developed by the Korea Institute of Ocean Science and Technology (KIOST). INBUS is a buoy equipped with an instrument frame, which is similar to other buoys that are fixed to the sea surface. During every measurement, INBUS detects the water depth and sends the frame down to the seabed to measure the water quality at every vertical level set up in the system. For example, if N levels are set in INBUS, the water depth of each measurement is divided by N layers and the instruments in the lifting frame measure the water properties of each of the N layers while they are descending to the bottom. Based on this procedure, the vertical structure of the water column is consistently measured in N layers regardless of changes of the water depth due to tides and waves. The lifting and measuring process is automatically controlled by INBUS once it is set up in the system. In addition, because INBUS allows bidirectional communication through code division multiple access (CDMA), the system can be controlled by stations on land. If the CDMA communication becomes inoperable owing to extreme wave conditions or the buoy is lost because of incidents such as a collision with a ship, the location of INBUS can be tracked by low-earth-orbit satellites.

The paper gives a historical overview, and a summary of key findings from 70 previously published research papers giving scientific data over the years from 1980 to 2019. They concern the flora and/or fauna in the mangrove forests along the Sri Lankan coast, addressing diversity, taxonomy, distribution, and ecological interactions. A total of 28 mangrove floral species from 13 plant families have been reported so far. Similarly, faunal diversity studies have reported 99 invertebrates, dominated by Arthropoda (n = 55) and Mollusca (n = 26), and 214 vertebrates comprising Pisces (n = 112), Aves (n = 72), Reptilia (n = 13) and Amphibia (n = 2). Most studies have been concentrated on the Southwestern coast (nflora = 20, nfauna = 6). Negombo has been a hotspot for mangrove research, with a higher number of studies (nflora = 11, nfauna = 5). The majority of the mangrove studies were focused on mangrove floral diversity and taxonomy and were conducted over recent years (2010–2019). Scientific data on mangrove fauna is restricted to a certain geographical extent. This paper intends to identify the research gaps in the field of Sri Lankan mangroves regarding various aspects and suggests advancement in future studies. Overall, outputs from the present study would be helpful for upcoming researchers to focus more on filling the gaps in knowledge.

The current study reports the cytochrome oxidase subunit 1 sequence of Gastropoda Ergalatax contracta from Busan, Korea. Four specimens were collected and extracted to obtain genomic DNA for the sequencing analysis. This is the first E. contracta sequence from Korea submitted to the NCBI for an accession number.

Glacier retreat is a major long-standing global issue; however, the ecological impacts of such retreats on marine organisms remain unanswered. Here, we examined changes to the polar benthic community structure of “diatoms” under current global warming in a recently retreated glacial area of Marian Cove, Antarctica. The environments and spatiotemporal assemblages of benthic diatoms surveyed in 2018–2019 significantly varied between the intertidal (tidal height of 2.5 m) and subtidal zone (10 and 30 m). A distinct floral distribution along the cove (~ 4.5 km) was characterized by the adaptive strategy of species present, with chain-forming species predominating near the glacier. The predominant chain-forming diatoms, such as Fragilaria striatula and Paralia sp., are widely distributed in the innermost cove over years, indicating sensitive responses of benthic species to the fast-evolving polar environment. The site-specific and substrate-dependent distributions of certain indicator species (e.g., F. striatula, Navicula glaciei, Cocconeis cf. pinnata) generally reflected such shifts in the benthic community. Our review revealed that the inner glacier region reflected trophic association, featured with higher diversity, abundance, and biomass of benthic diatoms and macrofauna. Overall, the polar benthic community shift observed along the cove generally represented changing environmental conditions, (in)directly linked to ice-melting due to the recent glacier retreat.

Unavoidable tip clearance between blade tip and casing shroud plays an important role in the performance and characteristics of a tidal propeller turbine. In this work, the tip-leakage vortex (TLV) induced in the end-wall region was numerically illustrated by using the shear-stress transport (SST) k–ω turbulence model at various flow conditions and different tip-clearance sizes (TCSs). The swirling strength criterion was employed to visualize the tip-leakage vortex trajectory and investigate vortex evolution according to clearance size change. Although TLV occurs in both design and off-design conditions, vortex intensity develops strongly under excess flow rate with increased tip gap. The extreme influence of TCS on the turbine’s generated power and efficiency was predicted in steady simulations for four TCS cases, namely, δ = 0%, 0.25%, 0.5%, and 0.75%. With the extension of the tip gap, turbine performance was drastically reduced because of vigorous turbulent leakage flow combined with considerable volumetric loss. The effect of TCS on pressure fluctuation intensity were also explored on the basis of the transient simulation statistic. Maximal pressure variation amplitude and dominant frequency were presented in spectrum analysis utilizing fast Fourier transform.

Ko, D.H.; Park, J.-S., and Lee, K.-S., 2018. Assessment of tidal current energy potential at Uldolmok in the southwestern coast of Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1301–1305. Coconut Creek (Florida), ISSN 0749-0208. Quantitative assessment for the tidal current energy potential and marine conditions should be preceded to construct the optimal tidal energy farm. Assessment of tidal energy resource at Uldolmok which is the optimal candidate sites for tidal energy farm was carried out. In order to collect the field data, static survey using ADCP(Acoustic Doppler Current Profiler) was conducted and harmonic analysis was done to predict the annual tidal current. As a result, the dominant direction of ebb current was southeast and flood current was northwest. The maximum ebb current speed was about 4.09 m/s. While, annual power density...

A specimen of the blue-lined octopus, Hapalochlaena fasciata (Hoyle, 1886) was collected from a tidal pool on the southern coast of Jeju Island, Korea, on 10 September 2015 and identified by DNA barcoding. This species is characterized by its blue middle lines on dorsal and lateral mantle and head, with development of numerous small papillae on the mantle, head, and arms. A molecular analysis of the mitochondrial DNA cytochrome oxidase subunit I gene showed that the specimen belonged to H . fasciata with 98.8% sequence similarity. The proposed Korean name is “Pa-ran-seon-mun-eo”. The present study far expanded the geographic distribution of H. fasciata , and further monitoring is to be made for this venomous octopus species.

Blue carbon science requires the estimates of organic carbon stock and sequestration rate; however, holistic data analysis remains limited in South Korea. The present study reports current organic carbon stocks and sequestration rates in the coastal areas of West Sea, South Sea, and East Sea of South Korea, encompassing entire intertidal areas using long-term field survey combined with remote sensing technology. Twenty-one intertidal flats were targeted across seven provinces (Gyeonggi, Chungnam, Jeonbuk, Jeonnam, Gyeongnam, Gyeongbuk, Gangwon). Out of the evaluated environmental parameters, mud content represented a significant factor controlling sedimentary organic carbon stocks across target areas, and was significantly positively correlated to the total organic carbon (p < 0.05). Organic carbon stocks measured in salt marshes (i.e., upper intertidal zone) reflected the high carbon fixation capacity of halophytes through primary production. Sediment textural type was classified using analysis of remotely sensed imagery, and was closely correlated to field-based classification data (p < 0.05). Using field and remote sensing results, we estimated total organic carbon stocks (13,142,149 Mg C) and sequestration rates (71,383 Mg C yr-1) in the tidal flats of South Korea. This study presents the first report on blue carbon potential in the Korean tidal flats, providing baseline information on the carbon dynamics of intertidal sediments in this region and, potentially, elsewhere.

Seventy-six species of fishes, representing 60 genera and 34 families, were recorded from tidal pools on Jeju Island, southern Korea. The major families in terms of species were the Gobiidae (11 species), Pomacentridae (8 species), Blenniidae (6 species), and Labridae (5 species). Thirty-nine species were classified as tropical, 26 as temperate and 11 as subtropical.

In order to evaluate water quality and biological productivity, observation data sets were collected and analyzed in Yeongsan River Estuary, Korea. We also set up a numerical model to resolve hydrodynamics and fate of water quality variables in the system. Results show that most of nutrients loading are trapped in the lake and higher concentrations of nutrients and organic matters (OM) are present only inside of the artificial sea dike. There exist episodial discharges at the dam, which coincide mostly with rainfall events during summer monsoon periods. During this discharge event, lower salinity and higher suspended solids, nutrients, and OM are observed in surface layer of the estuarine section. Hydrodynamic model results show that circulation in the estuarine section is governed by freshwater discharge from the lake, resulting in an enhanced two-layer estuarine circulation being dominated, during and after the freshwater is discharged. Such two-layer estuarine circulation combined with higher concentration of nutrients in the surface layer results in that outfluxes of nutrients in the surface layer dominate over the influxes in the bottom layer during summer high precipitation periods. Meanwhile, numerical dye experiment results show that the discharged water with elevated nutrients levels have a short residence time (∼5-10 days) in the estuarine section. Due to this fast flushing rate, excessive nutrient loadings are not used to produce biological matters in the estuarine section. This limited biological productivity, characterized by seaward side of the artificial sea dike, makes Yeongsan estuarine system excluded from acting as an active carbon sink.

The west coast of Korea has experienced environmental deterioration for more than half a century. In the present study, we specifically aimed to: i) evaluate potential toxicities of contaminants in sediments that cause effects mediated through the aryl hydrocarbon receptor (AhR) and estrogen receptor (ER); ii) determine spatio-temporal distributions of polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APs); and iii) identify causes of greater potencies of samples. From 2010 to 2014, sediments were collected from 12 major estuarine and coastal regions along the west coast of South Korea. In vitro cell bioassays were performed to determine AhR- and ER-mediated potencies using H4IIE-luc and MVLN cells, respectively. Fifteen PAHs and six APs in sediments were identified by GC/MSD. Results of bioassays generally showed a low-to-moderate degree of contamination, however, greater AhR- and ER-mediated potencies were measured at some locations. Concentrations of PAHs and APs varied among locations, which indicated that sources were independently affected by the surrounding environment (e.g., industrial complex and cities). Results of bioassays were generally well correlated with concentrations of putative causative chemicals. Benzo[k]fluoranthene, dibenz[a,h]anthracene, and benzo[b]fluoranthene were the major AhR agonists, explaining approximately 30% of the bioassay-derived benzo[a]pyrene equivalent concentration (BaP-EQ). Unknown AhR and ER agonists and potential mixture effects remain in question. Overall, the present study provides baseline information on chemical contaminations and potential toxicity of sediments in a fairly wide geographical region of the west coast of South Korea.

While there have been many reports of the species ‘Berkeleya scopulorum’ from Northeast Asia mainly as Navicula scopulorum, the observation of the living specimen of the species has revealed that the species should be the member of the genus Climaconeis. Here we describe the species as Climaconeis mabikii sp. nov. based on microscopic observations by means of both light (LM) and scanning electron microscope (SEM). As part of the review, the regional distribution of C. mabikii as well as the worldwide biogeography of the taxa belonging to the genus Climaconeis are discussed. Newly described C. mabikii from the present study is the seventeenth member of the genus. The discovery of the true identity of the diatom identified for a long time as ‘Berkeleya scopulorum’ and its description as a new Climaconeis species contributes to the proper appreciation of the diversity of the Northeast Asian diatom assemblage and fills old gaps in the published records.

Sedimentary organic matters in the typical intertidal areas were investigated to address year-round monthly distributions and site-specific sources. Target areas included four natural tidal flats (Ganghwa, Garolim, Sinan, and Suncheon) and one artificially closed estuary (Nakdong River), South Korea (in 2018). Among the parameters monitored, mud content was a key factor controlling organic matter contents, across varying habitats, with significant positive correlations to total organic carbon (TOC, r = 0.66, p

As global energy consumption continues to increase, the negative impact of global warming also grows. Therefore, eco-friendly energy policy is being established all over the world. Korea’s energy consumption problems are further complicated by the country’s high dependence on energy sourced overseas. Korean energy policy is evolving rapidly to address these problems. Korea has begun to phase out nuclear power and is focusing on developing new sources of renewable energy. So there has been substantial interest in the development of ocean energy. Of all ocean energy technologies, tidal current energy is the closest to the commercialization. Especially, the southwestern coast of Korea is the most promising candidate site for the development of tidal current energy owing to the abundant tidal current energy resource. Meanwhile, ocean energy policy is an important factor in determining the development of ocean energy. Thus, this paper presents the overview of the current status of policy and technology for the tidal current energy system in Korea. These policies explained in this paper can provide significant interest and motivation for the use of tidal current energy resources.

The species composition of tidal pool fish on the coasts of Jeju Island was preliminarily investigated for the first time, looking at tidal pool fish diversity by sampling relatively large tidal pools (n = 7, 28.3–326.9 m2 in area) in four regions. Fifty species belonging to 23 families (20–37 species per region) were collected, including a single unrecorded species. The most speciose family was Gobiidae (eight species) followed by Pomacentridae (seven species) and Blenniidae (six species). Yerae (southern coast) exhibited the most diverse composition with 37 species, whereas Oedo (northern coast) had the least with 20 species. Ten species were collected across all four regions. In spite of the short study period, the species richness of Jeju Island is high, and thus we can now better understand the biodiversity and ecological importance of the intertidal zone, particularly in tidal pools. However, direct comparisons of fish diversity between similar studies would not be proper considering the differences in environments. Therefore, comprehensive and intensive research is required into the rocky marine biodiversity of this island, including tidal pools, to better understand the fish diversity.

Trophodynamics of intertidal mudflats are significantly driven by microphytobenthos (MPB) production but spatial and temporal dynamics of this production source is poorly known. To understand the temporal dynamics and spatial heterogeneity of intertidal MPB, benthic chlorophyll a, phaeopigments, and sediment properties were determined in Gyehwa (sandy) and Gwanghwal (muddy) tidal flats of Saemangeum area over a year at 97 stations. This study set out to: (i) characterize the spatial-temporal patterns in MPB biomass on a year-round basis, (ii) identify the abiotic and biotic factors associated with MPB distributions, (iii) investigate the use of satellite-derived chlorophyll a data and verify with in field measurements, and (iv) determine minimum required sample size for in situ biomass measurement. Concentrations of benthic chlorophyll a and phaeopigments were greater in winter and spring with a high magnitude of variance than in summer and fall at both areas. Benthic chlorophyll a and phaeopigments tended to decrease approaching lower tidal zone, being associated with the corresponding decrease in shore level and/or exposure duration. Compared to available data on macrozoobenthos distribution, the spatial variation of microalgal biomass seems to be attributed to distribution of deposit-feeders. A significant positive correlation (p < 0.001) between in situ MPB biomass and satellite-derived normalized difference vegetation index (NDVI) values was observed, but was much weaker in the lower tidal zone. Mirroring algal heterogeneity, the minimum required sample size for in situ biomass measurement were greater in blooming season and sandy bottom, suggesting that sampling design for spatio-temporal mapping of MPB should consider the sampling season and/or abiotic and biotic features of study area. Overall, spatio-temporal dynamics of intertidal MPB seem to be influenced by a combination of abiotic and biotic factors.

The Maenggol Channel and Uldolmok Strait, located on the south-west coast of Korea, have notably strong and complex currents due to tidal effects and to local geological factors. In these areas, electric power has been generated using strong tidal currents, the speed of which is more than 3 m/s during spring tides. The region also provides a shortcut for navigation. These tidal conditions are therefore sometimes useful, but may also cause terrible accidents or severe economic damage, in the absence of accurate information regarding ocean conditions. In April 2014, the passenger ferry MV Sewol capsized in the Maenggol Channel, with 295 passengers killed and 9 still missing. While this was unquestionably a man-made disaster, strong currents were one of the contributing causes. It was also difficult to conduct scuba diving rescue operations given strong current speeds, and accurate prediction of the time when the tide would turn was thus critically needed. In this research, we used the high-resolution coastal circulation forecasting system of KOOS (Korea Operational Oceanographic System) for analysis and simulation of strong tidal currents in such areas with many small islands, using measurements and modeling from this research area. For accurate prediction of tidal currents, small grid size-modeling was needed, and in this study, we identified a suitable grid size that offers efficiency as well as accuracy.

This paper presents a quantitative method for evaluating tidal energy extraction in Uldolmok Strait located in the southwestern part of the Korean Peninsula, which is well known for having an impressively fast tidal current speed, up to 6 m/s. The advantages of this method are expressed by maximizing the power captured by all the turbines deployed in a tidal farm and by optimizing the array layout size with twelve different configurations. The energy yield of the proposed designs is evaluated based on flow data for the hydrodynamic model used, impacts of sea depth, device installation constraints, and wake effects between the turbines on the farm. The results show that staggered layouts achieve higher efficiency for energy extraction than centered arrangements in all cases. Moreover, an array configuration with 48 turbines is least efficient for tidal farming as it suffers the highest energy losses caused by the wake effects in comparison with other designs. When considering the optimum energy yield and cost of energy for tidal farming, the small-scale farm could be the most satisfactory selection because it ensures the capital cost of the entire tidal project as well as minimizes the negative effects on the marine environments in Uldolmok.

To investigate benthic ecological quality associated with coastal pollution in the Bohai Sea and northern Yellow Sea, a sediment quality triad (SQT) approach was applied. Chemical (six groups of persistent toxic substances (PTSs) and 8 metals and metalloids), toxicological (AhR-mediated potency), and ecological (bacterial and meiofaunal communities) elements were selected and used in an integrated sediment assessment. The benthic meiofaunal community was newly analyzed and used as an additional component of the infaunal community during the SQT. Concentrations of chemicals and potential toxicity in sediments both indicated moderate to severe pollution in the study area, characterized by site-specific and land-uses. In particular, As, DDTs, and bioassay-derived dioxin equivalents exceeded corresponding sediment quality guidelines at nearly all locations. Limited occurrences of meiofaunal taxa (mean = 5.2) and relatively low species diversity, mainly comprised of nematodes (75.3%) and copepods (14.6%), among locations was generally consistent with pollution. The benthic community was consistent with compound-specific responses to gradients of contamination, particularly for As. Densities of two taxa, Nematoda and Nemertea exhibited strong negative correlations with concentrations of As. Compound-, site-, and taxa-specific variability of pollution of sediments was further supported by results of cluster analysis (CA) and nonmetric multidimensional scaling (NMDS). Finally, assessment integrating five benthic quality elements, including: 1) PTSs; 2) metals and metalloids; 3) sediment toxicity; 4) sediment microbiome; and 5) benthic meiofaunal community, explained contamination of sediments associated with land-uses, locality, or habitat. Status of the benthic community could not be explained by single component and their associations were not quantitative. Results of the integrated assessment, considering multiple benthic quality elements were useful to address overall quality of sediment, and were consistent with chemical-, species-, or site-dependent pollution of sediments in the Bohai and Yellow Seas.

Ocean energy is one of the most promising renewable energy resources. In particular, South Korea is one of the countries where it is economically and technically feasible to develop tidal curre nt power plants to use tidal current energy. In this study, based on the design code for HARP_Opt (Horizontal axis rotor performance optimizer) developed by NREL (National Renewable Energy Laboratory) in the United States, and applying the BEMT (Blade element momentum theory) and GA (Genetic algorithm), the optimal shape design and performance evaluation of the horizontal axis rotor for a 200-kW-class tidal current turbine were performed using different numbers of blades (two or th ree) and a pitch control method (variable pitch or fixed pitch). As a result, the VSFP (Variable Speed Fixed Pitch) turbine with three blades showed the best performance. However, the performances of four different cases did not show significant differences. Hence, it is necessary when selecting the final design to consider the structural integrity related to the fatigue, along with the economic feasibility of manufacturing the blades.

The marine phytal zone has received little attention as yet as a habitat of associated and symbiotic crustaceans, particularly copepods. We describe here the female and male of a new harpacticoid copepod species Zaus wonchoelleei from the green alga Ulva sp. attached to aquaculture floats at Tongyeong Marine Living Resources Research and Conservation Center, Gyeongsangnamdo, Korea. The new species is closely related to Z. unisetosus recorded from Japan and Korea and Z. goodsiri by having one inner seta on leg 2 endopod but can be easily distinguished by the combination of the following characters: leg 2 enp-3 with only 1 inner seta, setation of leg 5 exopod, segmentation of antennule, and sexual dimorphism of leg 2 endopod. The detailed taxonomic description of the new species, Z. wonchoelleei, addresses the similarity and/or distinctiveness of species in the genus Zaus and contributes to the discussion of characters found useful to justify the separation of closely related species reported or be...

The Shihwa Coastal Reservoir (SCR) was created to supply agricultural water during the construction of dikes for land reclamation, with this project representing a striking example of policy failure regarding tidal flat reclamation in Korea. After the completion of dike construction in 1994, the water quality inside the SCR drastically deteriorated. As a result, in 1996, the sluice gates were opened to dilute water pollution levels through the physical mixing of seawater from outside and freshwater from inside. Over the last 20 years, the Korean government has invested more than US $ 1.5 billion to recover SCR water quality by improving public sewage treatment systems, which is 2.7 times the cost of the original dike construction. Yet, within the reservoir, water quality has minimally improved, sediment pollution continues to be detected, and anoxic layers have been observed, due to stratification in summer. Severe sedimentary pollution caused by heavy metals and trace organic pollutants originating from the upstream regions of the watershed was evident during the SCR project; however, pollution levels appeared to decrease after seawater circulation. In parallel, the pelagic and benthic communities have also been affected by the deterioration of multiple water and sediment quality indices. While the recent construction of the tidal power plant has significantly increased the volume of seawater circulation, it has not been enough to improve the water quality of the upstream region of the SCR, where the water remains polluted. The SCR project presents a clear example that how incorrect policy leads to the mishandling of both coastal ecosystems and substantial governmental budgets.

A comprehensive review of benthic macrofaunal studies conducted along the west coasts of Korea over the last 40 years has been made by providing the most updated checklist of the Korean marine benthic invertebrates. Tidal flats were the very habitat of interest with inclusion of subtidal areas. As part of review, a critical re-identification of taxa is provided together with the analysis of faunal assemblages and the regional distribution of the species. A total of 624 species belonging to ten phyla has been compiled from 72 references. The phylum Annelida was found to comprise most taxa (n = 248) followed by Mollusca (n = 196) and Arthropoda (n = 135). While annelids prevailed in the subtidal area compared into intertidal, mollusk and arthropod species prevailed in the intertidal. Among 17 regions across the west coast of Korea, the Incheon exhibited the largest number of macrobenthic animals (n = 272) followed by the Jeonjupo where 173 species have been reported over the past 30 years. More than half of all species compiled are reported from one region only while certain opportunistic polychaetes e.g. Heteromastus filiformis widely distributed across the coast. Overall, we suggest that future macrozoobenthos studies in Korea should focus on long-term changes by broadening target species and regions that fully covered along the entire coast of Korea.

The present article presents a historical overview and key findings in the studies of microphytobenthos (MPBs) in Korea, supporting a biodiversity of the Korean tidal flats. The common internationally recognized topics relating to the tidal flat MPBs were found to be assemblages, dynamics, production, and food web etc. in chronological manner. Accordingly the review on the Korean MPBs studies was provided in the given topics, highlighting pros and cons of individual scientific efforts and data. Especially, the brief summary from the several representative works (selected based on citations) related with the corresponding topics were provided as for comparison, if applicable. The world studies of tidal flat MPBs over the past 100 years generally reflected the subjects being balanced followed by logical development of each topic. Although over 50 years of scientific gap between Korea and the European countries were evidenced historically, a rapid scientific advancement in recent 10 years would be noteworthy. A topic of floral assemblages was found to be steady issue in Korea, with documented MPBs of >400 species (ca. 10 new species) from the Korean tidal flats. As part of review, we reanalyzed our selected data from the previous and current MPBs works encompassing above 4 topics, where our key ecological findings were highlighted. Finally, future research direction was carefully discussed by comparative analysis between worldwide versus Korean studies in various aspects. Overall, the future MPBs studies in Korea would be promising to support unique biogeography in Asian tidal flats, yet with certain limitation in scientific recognition and/or methodological weakness.

The present article presents a historical overview of the Saemangeum reclamation projects and key findings from the ecological studies of the Saemangeum tidal flat, highlighting the ecological impact against the grand reclamation project, as a model example, in Korea. First, the scientific efforts given to the area of interest, mainly the inner part of the dikes, during the construction periods of series of four dikes (1991–2006) were summarized in terms of the change of environmental condition followed by the ecological responses over the past 20 years. As part of review, we selected and reanalyzed our series of the Saemangeum data including the current works relating to the microphytobenthos and macrozoobenthos, where the spatio-temporal variations cross the benthos in association with dike effects were carefully discussed in detail. The species composition in the upper intertidal zone, situated relatively far from the dikes, have been lesser changed between the periods of before (1988) and during the dike construction (2003–05). However, the benthic assemblages appeared to be changed in the mid to the lower intertidal zones of several transects and such phenomenon strengthened for the locations near the completed dike, e.g., Sandong transect near the dike of sector IV. Meanwhile, changes of the representative zoning in benthic assemblages during the dike construction were much clearly observed for the faunal species rather than flora. Such long-term ecological impacts including the timely increase of the opportunistic species during the dike construction were further evidenced the compositional change of the dominant benthos spanning two decades or so. In general, a long-term change in benthic community structure clearly reflected the community level impact apparently due to the attenuation of tidal energy by the embankment, varying the degree of impacts depending on the geographical location. Interdisciplinary monitoring and modeling studies are highly recommended to track natural variations in water quality and ecosystem health. Overall a long-term ecological monitoring should be applied to direct sound policy toward conservation of tidal wetlands, by emphasizing the significant biodiversity decline and coastal landscape depreciation.

Kwon, B.-O.; Koh, C.-H.; Khim. J. S.; Park, J.; Kang, S-G., and Hwang, J.H., 2014. The relationship between primary production of microphytobenthos and tidal cycle on the Hwaseong mudflat, west coast of Korea. The present study examined variation in sediment temperature and irradiance with respect to microphytobenthos primary production at the Hwaseong mudflat, west coast of Korea, under different tidal cycles. The study was carried out during March and April 2009, which encompassed two spring tides and one neap tide. It was not possible to continuously measure primary production in situ across the tidal cycles; hence, photosynthesis–irradiance (P-I) curves at different temperatures were obtained experimentally in the laboratory. These readings were then used to calculate primary production, by projecting in situ mooring records of irradiance and temperature onto the P-I curves. The sediment temperature and irradiance were measured continuously, and the averages of 10-minute intervals from the mo...

The intertidal zone of Jeju Island, Korea, is characterized by well-developed volcanic rocks with high wave action. During low tide, numerous small tidal pools are formed on the rocky intertidal zone, which provide shelter and habitats for benthic organisms. Previous investigation indicated that many species of micromolluscans inhabit the tidal pools; however, only a few studies have reported the ecology and identification of these microshells. In this study, we have identified a microgastropod, Ammonicera japonica Habe, 1972 (Omalogyridae), from a tidal pool on the southern coast of Jeju Island. Morphological identification of the species was based on scanning electron microscopy (SEM) of the protoconch and teleoconch. A. japonica was found to be associated with encrusting coralline algae distributed on the bottom of the tidal pools. This is the first report of A. japonica from Korea, and the specimen was registered at the National Marine Biodiversity Institute of Korea (MABIK MO00157413).

We report the first record of partial albinism in Dictyosoma rubrimaculatum, collected from Jeju Island, Korea, in July 2015. This specimen has yellowish white coloration of the body, head, and all fins, except for dark stripes on the snout and anterior region of the opercle, dark blotches on the anterior tip of the lower jaw, black eyes, and small melanophores on the posterior region of the body.

Contamination of water and sediment with arsenic (As) in a highly industrialized area of Pohang City, Korea was investigated, with emphasis on in situ bioaccumulation of arsenicals by various aquatic organisms. Species- and tissue-specific concentrations of arsenicals were determined by use of HPLC-ICP/MS and μ-X-ray absorption near-edge structure (μ-XANES). Concentrations of arsenic in aquatic organisms were strongly associated with corresponding water concentrations, which indicates point sources associated with land use and activities. Arsenobetaine was the most dominant form of arsenic found in fishes, bivalves, crabs, and shrimps, while As(III) was predominant in freshwater snails. The μ-XANES analysis provided additional information about the unidentified arsenicals such as As-thiol. Arsenicals were mainly localized in intestine of mullet and marsh clam. Distribution and bioaccumulation of arsenic were strongly correlated with salinity, which indicates that natural processes controlling biogeochemistry of arsenic would be important in estuarine lotic system.

In this study, flow-driven rotor simulations with a given load are conducted to analyze the operational characteristics of a vertical-axis Darrieus turbine, specifically its self-starting capability and fluctuations in its torque as well as the RPM. These characteristics are typically observed in experiments, though they cannot be acquired in simulations with a given tip speed ratio (TSR). First, it is shown that a flow-driven rotor simulation with a two-dimensional (2D) turbine model obtains power coefficients with curves similar to those obtained in a simulation with a given TSR. 3D flow-driven rotor simulations with an optimal geometry then show that a helical-bladed turbine has the following prominent advantages over a straight-bladed turbine of the same size: an improvement of its self-starting capabilities and reduced fluctuations in its torque and RPM curves as well as an increase in its power coefficient from 33% to 42%. Therefore, it is clear that a flow-driven rotor simulation provides more information for the design of a Darrieus turbine than a simulation with a given TSR before experiments.

The influence of industrial and/or municipal contaminant inputs on the aquatic environment of Pohang, Korea was investigated, with a focus on bioassay combined with instrumental analysis. Pohang is the most heavily populated city in Gyeongsangbuk-do province of Korea, with more than half a million residents, and also hosts the nation's biggest steel manufacturer and related industries. Sediment (n = 15) and surface water samples (n = 17) were collected from Hyeongsan River which runs across the Pohang city, in two separate events, i.e. , June 2010 and February 2011. Sediment samples were first Soxhlet-extracted (raw extract) and were measured for estrogenicity using H295R cell line, and also analyzed for alkylphenols (APs), bisphenol A (BPA), PAHs, and PCBs. For sediment samples which exhibited greatest effects in the cell line, further fractionation was performed into non-polar, mid-polar, and polar portions. In surface water samples, heavy metals were also analyzed. Among 15 sediment samples, station S2 near the steel industry complex and station M3 near the municipal area showed the greatest sex hormone changes, and these changes were generally explained by the fractions which contained APs and BPA. Principal component analysis (PCA) however suggests that chemicals that were not analyzed in the present study would better explain endocrine disruption capacity of sediments. In water samples, adverse effects on hatchability and growth of Japanese medaka fish, and on Daphnia reproduction were noted following exposure to six water samples collected from stations near industrial and municipal areas. Several heavy metals and nonylphenol (NP) concentrations exceeded surface water quality guidelines, suggesting adverse effects of contamination inputs from both industrial and municipal activities. Observed estrogenicities in stations such as S2 and M3 warrant further investigations on longer term ecosystem impacts near industrial and municipal areas. The levels of major organic chemicals in sediments are quite comparable to those reported in ~ 10 years ago, emphasizing a need for source control.

We extensively reviewed the macrozoobenthos around Dokdo, Korea, by analyzing metadata collected over the past 50 years. The Dokdo macrozoobenthos was represented by 578 species belonging to 243 families from 12 phyla, where four major phyla (or classes) collectively accounted for 86% to total. Mollusks, arthropods, and cnidarians were semi-equally occurred in intertidal and subtidal areas, while polychetes dominated the subtidal zone. The northern most region of Dokdo had the greatest biodiversity (173 species). The taxonomic distinctness analysis (delta +) indicated a close association between species by region, although the number of species varied greatly. About half of the species did not occur cross the locations (n = 20), indicating strong habitat preferences of Dokdo macrofaunal assemblages. Overall, the diversity of Dokdo was greater than that of Ulleung Island (east coast), but comparable to that of the well-developed tidal flats in the western Korean waters, highlighting its status as a biodiversity hotspot.