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Jeong, J.B.; Woo, H.J.; Jung, H.-S.; Park, H.N.; Kim, T.-J, and Lee, J.-H., 2021. Monsoon-influenced deposition systems in a rhodolith beach on Udo Island, Korea. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 41–45. Coconut Creek (Florida), ISSN 0749-0208. A beach on Udo Island, off the coast of Jeju Island, Korea was formed by long-term deposition of rhodoliths, which comprise more than 99% of all deposits on the beach. This phenomenon is very rare on the global scale. This rhodolith beach in 2004 was designated a natural monument to preserve its geoheritage. However, to date, no geological studies have been conducted to examine its sedimentary mechanisms and properties. Recent tourist developments and climate change have raised the possibility of erosion on the rhodolith beach. The objective of the present study was to examine the evolution and sedimentation characteristics of this beach through analysis of grain size and aerial photographs, and seasonal beach surveys. Geomorphologically, the beach is divided into reef areas to the north, with high altitudes and rocks mainly distributed along the coastline, and sandy beach to the south, which is strongly affected by waves and tidal currents. Particle sizes decrease toward the upper part of the beach, with gravel-sized sediments in the south and sand-sized sediments in the north. The mean grain size of deposited sediments increases from spring to autumn. In spring, the beach experiences greater erosion in the north and deposition in the south, whereas in summer, the opposite trends are seen. The sediment deposition volume is largest in autumn. There is also annual variation, where the beach was dominated by erosion in three recent years due to a decrease in sediment volume toward the south. The beach increased in volume from 1985 to 2003, and decreased thereafter. Due to the influence of the East Asian Monsoon, the beach experiences typhoons in summer and north-northwesterly waves and tidal currents in autumn and winter. However, erosion occurs in in the south due to a lack of berm for rhodoliths deposition.

Lee, J.-H.; Woo, H.J.; Jung, H.-S.; Park, H.N.; Jeong, E.-Y., and Jeong, J.B., 2021. Characteristics of the wind distribution using automatic weather system observation data over the Doyo-deung barrier islands off the coast of the Nakdong River estuary, Busan, South Korea. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 36–40. Coconut Creek (Florida), ISSN 0749-0208. This study was conducted to the Nakdong marine environmental information system (N-MEIS) using automatic weather station (AWS) observation data to elucidate the characteristics of the wind distribution, focusing on and land and sea breezes, over the Doyo-deung barrier islands in the brackish water zone off the coast of the Nakdong River Estuary, Busan, South Korea. From May 2015 to the present, the N-MEIS was run in real-time using 4th Generation (4G) long term evolution (LTE) communication, with a coverage rate of approximately 98% from AWS, along with periodic marine observations recorded one to four times per year. From April 2016 to August 2020, the average monthly wind speed over the Doyo-deung barrier islands was 3.82 m/s (range, 2.10–5.10 m/s) and the maximum wind speed, recorded in February 2019, was 46.80 m/s. These values are generally influenced by low-pressure cyclones or gusty winds. However, the maximum monthly mean velocity may be influenced by typhoons occurring in early autumn, from August to September. Based on the percentage of each wind direction, the prevailing winds are from the N, NNE, SSW, and NNW. The distribution of wind directions in summer was similar to that in spring, while that in autumn tended to be similar to that in winter. However, considering only wind speeds of 5.00 m/s or more, which can cause the movement of sand particles, N, SSW, and NNW winds are overwhelmingly dominant, at 38.7%. Research into the dynamic wind distribution is essential to effectively managing erosion and sedimentation around barrier islands, beach pollution from floating materials transported overland, coastal sand dune activity, changes in migratory bird habitats, and impacts on ecosystem health. The evolution and development of the N-MEIS will facilitate this process. Future studies should integrate real-time data with periodic marine observations and predictions and environmental sensitivity index maps.

Contamination in coastal aquifer plains is of great concern in many countries given that non-aqueous phase liquids (NAPLs) have polluted numerous sites through accidental oil spills or improper disposal. We have developed a method to remove pollutants such as NAPLs from sandy sediment samples collected from the Mandol area of Gomso Bay in western South Korea. The sediments were collected from around the diffuser in a two-dimensional (2D) acrylic reaction apparatus, and these contained a total petroleum hydrocarbon (TPH) concentration of 89.3 ppm (mg/kg media). The maximum perchloroethylene (PCE) concentration was 398.51 ppm in the unsaturated zone and 0.77 ppm in the saturated zone. Volatile organic compounds (VOCs) were detected between 20 and 44 hour. However, non-volatile contaminants remained in the sediments after treatment. In situ air sparging (IAS) combined with soil vapor extraction (SVE), transformation from sorbed and nonaqueous phases to the vapor phase, is incomplete when treatment is performed using a pervasive air flow for sediments such as the sand of Mandol. During air transformation, the groundwater flow conditions increased the rate of contaminant removal. Although pilot-scale testing in the field site was fluctuated due to the heterogeneous of sediments condition, this 2D study found that the proposed method can alter the measurable geophysical properties of NAPLs. These findings demonstrate that IAS combined with SVE in the saturated zone is an effective technology for aquifer remediation high applicability of sandy coastal sediments contaminated by NAPLs.

Choi, J.U.; Lee, Y.G.; Jeong, D.U.; Choi, Y.H., and Woo, H.J., 2018. Effects of Abalone Farming Cage Removal on the Benthic Foraminiferal Assemblages. 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. 321–325. Coconut Creek (Florida), ISSN 0749-0208. To improve the aquaculture environment of an abalone farm near the Bogil Island, relocation was executed via the partial relocation of cages. The surface sediments were collected from nine stations to analyze the grain size, geochemical characteristics, and benthic foraminiferal assemblages in May (before) and August (after) 2015. Although no distinct environmental changes in the cage area were observed, the relocation area had an increased sand content caused by water circulation. In addition, despite the increase in the sediment temperature, the ignition loss decreased while the dissolved oxygen in the se...

Jeong, E.J.; Woo, H.J.; Kang, J.; Lee, J.-H., and Choi, J.U., 2018. Study of Holocene paleo-environmental evolution using cores from the downstream area of the Nakdong River Delta, 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. 626–630. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River Delta in Korea consists of wide and thick sediments, which are excellent for undertaking highresolution investigations of paleo-environmental evolution. This study describes the horizontal evolution of the sediment environment during the Late Quaternary based on the KND-3 and ND-3 cores obtained from the downstream area of the Nakdong River Delta. The lowest sediments in these cores differ markedly, with KND-3 mainly being composed of olive gray coarse, sandy sediments with pebbles of c. 2-cm diameter, which are interpreted as representing a paleo-channel environment, and ND-3 mainly consisting of red silty sediments (paleosol), which are interpreted as representing alluvial deposits that were exposed to the atmosphere. By contrast, the upper sediments above 40.00 m in both cores were deposited when the sea level rose to a similar level as seen today, at which time both cores evolved through a succession of environments from estuary complex, through to shallow-marine, prodelta, delta front, and the present-day delta plain.

Woo, H.J.; Lee, J.-H.; Kang, J., and Choi, J.U., 2018. Sedimentary processes of barrier-lagoon system in the Nakdong river estuary, Busan, South 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. 1–5. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River Estuary on the southeastern coast of the Korean Peninsula is enclosed by two large estuarine dams, one constructed in 1934, and one between 1983 and 1987. The estuary has been characterized as a barrierlagoon system with various subenvironments and micro-tidal ecosystem and a mean tidal range of 1.07 m. The monitoring short-term sedimentation rates and suspended sediment characteristics were investigated to understand sedimentary processes in the barrier-lagoon system of the Nakdong River Estuary. The surface sediments generally showed sand sediment was dominated along the seaward side of the barrier islands and muddy sand sediment was dominated within the lagoon. The short-term sedimentation rates for a year showed that deposition dominated the tidal flats between the mainland and Jinudo (JW-line) and the mainland and Sinjado (SJ-line), with net deposition rates of 10.09 and 12.38 mm/year, respectively. Erosion dominated the tidal flat for two years at the southern end of Eulsukdo (ES-line), which is located on the eastern side of the system, at an annual rate of −12.76 mm/year. Four 12.5-hour anchoring surveys conducted at the inlets and channel revealed that net suspended sediments were transported to the open sea during a tidal cycle in summer. The sedimentary processes of the Nakdong River Estuary showed that sediments were transported into the lagoon through inlets during floods and moved westward and/or northwestward; they were then deposited on the tidal flats and in channels near the dams under low energy conditions. Within the eastern side of the system, sediments flowed out of the sea with discharge from the Nakdong Dam during ebb conditions. The major control factors for seasonal variations in these sedimentary processes within the barrier-lagoon system were waves, tidal currents, and dam discharges.

Lee, J.-H.; Jeong, K.-S.; Lee, D.-H.; Park, K.S., and Woo, H.J., 2018. Elemental (C/N Ratios) Isotope compositions (δ13CTOC and δ15NTN) of surface sediments from the barrier islands in the Nakdong river estuary, South 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. 36–40. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River Estuary (NRE) in South Korea is a typical, artificially manipulated estuary that is blocked by two large dams. The estuary is characterized by a barrier-lagoon system with various subenvironments and a microtidal domain with a mean tidal range of 1.07–1.50 m. The stable isotopic values (δ13CTOC and δ15NTN) and elemental (C/N ratios) compositions of organic matter, including those of halophytes, from the barrier islands were investigated in the NRE. In May (n = 94) and August (n = 90) 2015, sediment samples were collected on and around three islands in the NRE. The mean grain size of the barrier island system in the NRE ranged from 1.1 to 8.9 Φ (average 3.9 Φ) and the sediment types included muddy sand, sandy mud, and mud. The relative low C/N ratios (average 5.88) imply that the deposited organic matter originated from autochthonous algae derived-sources. The δ13CTOC ranged from −28.2 to −16.8‰VPDB (average −22.5‰VPDB), with δ15NTN in the range 6.2–12.5‰AIR (average 9.4‰AIR). Two halophytes (Phragmites communis and Scirpus planiculmis) had δ13CTOC values that ranged from −29.0 to −25.3‰VPDB (average −26.5‰VPDB) at ES-R and ES-5. The isotope and elemental composition of sedimentary organic matter (δ13CTOC and δ15NTN) indicated the deposition of algae-derived organic matter with limited input from terrestrial organic matter. These results suggest that the microphytobenthos contribution was greater than the inflow of surrounding land vegetation and sediments to the north of the barrier islands had a marine origin. To the south, the effect was considered mixed. Further studies should determine the effects of end-member discrimination on the origins of the organic matter, such as the advance signature proxy. It is necessary to continue measuring sediments and water in the brackish water zone around the barrier system with on-site monitoring of dam discharge, tidal currents, waves, and, etc.

The flux and distribution of methane (CH4) was investigated in the seawater column at 14 stations in the Gunsan Basin, the southeastern part of Yellow Sea from 2013 to 2015. Here CH4 is concentrate...

Lee, J.-H.; Jeong, K.-S.; Kang, J.; Park, K.-S., and Woo, H.J., 2017. Benzene, toluene, ethylbenzene, xylene, and styrene (5VOCs) distributions at the barrier island system in the Nakdong River estuary, South Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 89–93. Coconut Creek (Florida), ISSN 0749-0208. Total Volatile Organic Compounds (TVOCs) were extracted from 18 surface sediment samples collected in and around barrier island system in the Nakdong River Estuary (NRE) on the southeastern Korean Peninsula in May 2015. TVOC emissions from sediments were measured using a Thermal Desorption System-Gas Chromatograph-Mass Selective Detector (TDS-GC-MSD) for 30 min at 25°C at the National Center for Inter-university Research Facilities (NCIRF), Seoul National University, South Korea. The thermal extractor (Gerstel, Germany) was equipped with an adjustable oven (temperatu...

Rare earth elements (REEs: La-Lu) in surface sediments collected from the mouth and middle tidal flats of Gomso Bay, South Korea, in August 2011 and May 2012 were analyzed to investigate the fine-grained sediment provenance. The upper continental crust (UCC)-normalized light REEs (LREEs: La to Nd) were more enriched than the middle REEs (MREEs: Sm to Dy) and heavy REEs (HREEs: Ho to Lu), resulting in large (La/Yb)UCC (1.9 ± 0.4) to (Gd/Yb)UCC (1.4 ± 0.2) ratios. The monthly (La/Yb)UCC values differed between the mouth and middle tidal flats due to deposition of fine-grained sediments that originated from distant rivers (the Geum and Yeongsan) and the Jujin Stream, located on the southern shore of the inner bay. We observed relative reductions in the (La/Yb)UCC value and REE content in the sediments from the mouth of the bay compared with those from Jujin Stream sediments. Confined to the middle tidal flat around the KH Line of Jujin Stream, the sediments, most enriched in LREEs but depleted in Eu, were distributed in August as strong Jujin Stream runs. Here, we suggest that an increase in LREE/HREE and decrease in MREE/LREE ratios can be used as a proxy to identify the Jujin Stream provenance in mixed riverine sediments and to trace Jujin Stream sediments within the Gomso Bay tidal flat, especially in the summer rainy season.

A sequence stratigraphic analysis was conducted using high-resolution ‘Chirp’ seismic profiles and a long core data off the Nakdong River where Holocene deltaic deposition prevails in the Korea Strait. The depositional sequence comprises a group of transgressive and highstand systems tracts, intercalated with their bounding surfaces of maximum flooding surfaces, above a sequence boundary. It is formed by an erosional process within an incised valley, indicating the Nakdong River at the lowstand of sea level. The transgressive systems tract consists of the lower and upper depositional units, bounded by a ravinement surface, formed during the early Holocene when sea-level rose between 12.0 and 6.0 ka BP. The lower depositional unit mostly occurs in the incised valley area, comprising fluvio-estuarine sediments, whereas the upper one nearshore environments consist of sand sheet and ridges. The overall stacking pattern of these sequences demonstrates retrogradation. During the late Holocene sea-level highstand of around 6.0 ka BP, the highstand systems tract overlying the maximum flooding surface consists of the deltaic sequence, formed as a seaward sigmoid progradational pattern. The subaqueous Nakdong delta system has evolved to depositional units of the retrogradational transgressive and then the progradational highstand systems tract over a sequence boundary during the Holocene transgression.

Woo, H.J.; Kang, J.; Lee, J.-H., and Jang, S., 2016. Seasonal changes in sediment characteristics on the tidal flat in Geunso Bay, west coast of Korea. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1412 - 1416. Coconut Creek (Florida), ISSN 0749-0208. Geunso Bay, located in Taean, western Korean Peninsula, is a semi-enclosed-type bay with a mean tidal range of about 6 m. Tidal flats are largely developed along the sides of the bay. A digital elevation model showed that 95% of the total area of the bay is tidal flat. Observations in both winter and summer of 2009 revealed that the surface sediments in the bay were mainly muddy sand, and the sediments were classified into five sedimentary facies: sandy silt, slightly gravelly sandy mud/sandy mud, slightly gravelly muddy sand/muddy sand, silty sand, and sand. In the eastern tidal flat, the...

Lee, J.-H.; Woo, H.J.; Jung, H.-S.; Jeong, J.B., and Park, H.N., 2020. Application of a Marine Environmental Information System (MEIS) Data to marine spatial planning (MSP) in the Nakdong River Estuary, Busan Metropolitan City, South Korea. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 860–864. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River in South Korea is nearly 526 km long, and has a drainage basin of around 23,817 km2. It is subject to natural erosion and sedimentation, and there is also the potential for disturbance by various human activities, including water diversion and reservoir construction, and other large construction projects in the river estuary. The Noksan dike, built in April 1934, blocks the flow of the west Nakdong River. The Nakdong River Estuary (NRE) barrage in Busan Metropolitan City was completed in November 1987 to regulate the flow of the Nakdong River. In this study, Marine Environmental Information System (MEIS) data collected after May 2015 were used to support marine spatial planning (MSP) in the brackish water zone. The NRE and surrounding locations can be divided into areas managed by the government, protected marine areas, areas for sand mining, areas for the development of tourist attractions, areas of research conservation, areas where an environmental risk assessment would be required prior to use by ships, military areas, and coastal areas subject to safety management measures. Data on environmental changes in the estuarine watershed were used during the preparation of the NRE for partial opening and drainage extension in 2019. Data supporting MSP in the target area should be collected, processed, and analyzed to facilitate future decision-making, and databases should be established based on geological field surveys. Furthermore, protected areas should be designated according to governmental guidelines. All scientific data used in these processes should be validated, and spatial data to facilitate MSP should be produced.

Jeong, D.U.; Lee, Y.G.; Kang, J.; Woo, H.J., and Choi, Y.H., 2020. Sediment geochemistry and benthic foraminiferal response to fish farming after conversion from a red laver (seaweed) farm. Journal of Coastal Research, 36(3), 559–574. Coconut Creek (Florida), ISSN 0749-0208.To understand the effects of biodeposits discharged from a fish farm (which was previously a red laver farm) on geochemistry of the sediment and benthic ecology, trace metals and element analyses, 210Pb dating, and benthic foraminiferal analyses were conducted on sediment cores collected below the fish farm cages. Sediment core sampling was also carried out at a control plot (160 m away) to understand the spreading of biodeposits. The geochemical effect of fish farming is pronounced. There was an increase in silt content and sedimentation fluxes of Znex (Zn in excess fractions), Cuex, Asex, and TPex (total phosphorus in excess fractions) after red laver farming. The silt content increased from 45.01% to 50.07%, with a sediment accumulation rate of ∼0.61 cm/y, on average. TPex, with 0.15% ± 0.06% on average, showed that the fish farming effects increased by 0.22% ± 0.07%. Znex, Cuex, Cdex, and Asex showed a positive relationship with TPex increase: 19.92 ± 1.79, 10.23 ± 3.99, 0.57 ± 0.19, and 0.92 ± 0.04 µg/cm2/y, respectively. The high sedimentation fluxes of Znex and Asex in the control plot may signify an expansion of influence of the fish farm by tidal currents. Seven benthic foraminifera appeared during the fish and red laver farming periods, with the dominant species being Cribroelphidium excavatum; however, they were characterized by a high similarity index of 88.1% and very low frequency of abundance, indicating bad habitat conditions. Among them, the C. excavatum–Ammonia beccarii–Ammonia ketienziensis–Cribroelphidium subarcticum assemblage ranged from 21 cm depth to the uppermost layer, characterized by increases in A. beccarii. This increase may have been caused by the accumulation of organic matter discharged from the fish farm after red laver farming, rather than from an increase in the trace metals. A. beccarii may be a species tolerant to fish farming.

Anthropogenic activities have altered the geomorphological and ecological conditions of the Nakdong River Estuary (NRE) dramatically over the last century. The objectives of this study were to classify NRE sub-environments and to identify their unique ecological functions. The first step in classification was the establishment of 14 a priori sub-environmental groups based on landscape factors. Surface sediments obtained for these groups were analyzed for factors related to grain size and organic matter. Based on the results, the NRE was divided into two primary estuarine environment divisions: (1) a mixed marine and terrestrial environment influenced primarily by land; and (2) a principally marine environment influenced primarily by the ocean. Using multivariate analysis, we subdivided these primary estuarine divisions into six sub-environments, including Sub-1 and -2 in the former and Sub-3, -4, -5, and -6 in the latter.

The flux and distribution of methane (CH

We comprehensively investigated sedimentary Hg in Yellow and East China Seas (YECSs), which constitute potentially important depocenters for large anthropogenic Hg emissions from mainland China. A large dataset of Al-TOC-Hg concentrations led to an in-depth understanding of sedimentary Hg in the entire YECSs, including distribution and its determinants, source-to-sink, background levels, inventory in flux and budget, and accumulation history. Especially, the net atmospheric Hg flux to the sediments was estimated to be 1.3 × 10−5 g/m2/yr, which corresponded reasonably well to that calculated using a box model. About 21.2 tons of atmospheric Hg (approximately 4% of the total anthropogenic atmospheric Hg emissions from China) were buried annually in the YECS basin. This result implies that most of atmospheric Hg from China is transferred to the surface of the Pacific (including the East/Japan Sea and South China Sea) by the westerlies and, consequently, can play a critical role in open-sea aquatic ecosystems.

Lake Shihwa suffers from trace-metal pollution discharged from the Banweol stream and the Shihwa Industrial Complex. Installation of floodgates in 2001 increased water exchange and decreased trace-metal content, thereby improving the benthic environment within the lake. We analyzed surface sediments (including grain size, pH, trace-metal concentrations), water-quality data, and the assemblages of, and prevalence of deformities in, the benthic foraminifera, to understand the effects of recent changes in salinity variability. Since spatial and temporal distributions of benthic foraminifera are known to vary in response to both biotic and abiotic environmental variables, they are useful indicators of environmental change. Since the installation of floodgates, surface-sediment composition coarsened from silt to sandy mud/muddy sand in response to increased water flow. Trace-metal contaminants (Ni, Cu and Zn) have decreased and are close to the Effect Range-Low (ER-L) designation. We identified 15 species of benthic foraminifera (3 agglutinated, 10 calcareous-hyaline, and 2 calcareous-porcelaneous). Buccella frigida and Elphidium albiumbilicatum were dominant, but seven sampling localities formed a nearly abiotic zone. Although trace contaminants have decreased, a high prevalence of test deformities (up to 65%) was observed, mostly in E. albiumbilicatum . Our findings suggest these abnormalities may be strongly related to the effects of seasonal variation of salinity in Lake Shihwa.

in theair sample collected in the chamber were measured using gas chromatography with an EG analyzer, model GS-23,within 6 hours of collection, and the other gases were measured in real time using a multi-gas monitor. The gasemission fluxes (source (+), and sink (-)) were calculated from a simple linear regression analysis of the changes inthe concentrations over time. In order to see the surrounding parameters (water content, temperature, total organiccarbon, average mean size of sediments, and the temperature of the inner chamber) were measured at the study site.On the first day, across three measurements during 5 hours 20 minutes, the observed CO

In order to determine the effects on foraminifera due to spilled crude oil in the "Herbei Spirit" incident, a study of benthic foraminiferal assemblages was carried out on sediment samples collected from the Sogeunri tidal flat, Taean Peninsula, Korea. Breakages of the chambers in the Ammonia beccarii and Elphidium subincertum species of the Sogeunri tidal flat with a low pH (6.98 on average) were marked. These chamber breakages occurred in 71.6% of A. beccarii and are thought to be caused by decalcification due to the fall in pH resulting from the "Hebei Spirit" oil spill. The factors that affect breakage of the chamber in benthic foraminifera under low pH condition may be not only deto decalcification but also to exposure duration of substrata in the tidal flat spilled crude oil.

To understand the degradation processes of organic matter related to sulfate reduction by Sulfate Reduction Bacteria (SRB) in the tidal flat sediments of Hwang-do and Sogeun-ri, Tae-an Peninsula in Chungnam-do, biogeochemical characteristics were analyzed and highlighted using specific microbial biomarkers. The organic geochemical parameters (TOC, δ 13 C org , C/N ratio, long-chain-n-alkane) indicate that most of the organic matter has been derived from marine phytoplankton and bacteria in the fine-grained sediment of Sogeun-ri, although terrestrial plant components have occasionally been incorporated to a significant degree in the coarse-grained sediment of Hwang-do. The concentration of sulfate in pore water is a constant tendency with regard to depth profile, while methane concentration appears to be slightly different with regard to depth profile at the two sites. Especially, the sum of bacteria fatty acid (a-C15:0 + i-C15:0 + C16:1w5) confirms that the these concentrations in Sogeun-ri are related to the degradation of Benzene, Toluene, Ethylbenzene and Xylene (BTEX) compounds from the crude oil retained in the sediments as a result of the Hebei Spirit oil-spill accident in 2007. The methane-related microbial communities as shown by lipid biomarkers (crocetane, PMI) are larger in some sedimentary sections of Hwang-do than in the Sogeunri tidal flat. These findings suggest that methane production by microbiological processes is clearly governed by SRB activity along the vertical succession in organic-enriched tidal flats.

Lee, J.-H., Choi, J.U., Jung, H.-S., Kwon, J.-I., and Woo, H.J., 2019. Development of a Marine Environmental Information System (MEIS) using data on Land–Sea interactions in the Nakdong River Estuary, South Korea. In: Lee, J.L.; Yoon, J.-S.; Cho, W.C.; Muin, M., and Lee, J. (eds.), The 3rd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 91, pp. 191-195. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River in South Korea is about 510 km long and is subject to natural erosion and sedimentation and various potential sources of human pollution, such as urban dumping and input from industrial complexes and many cities. This study developed a marine environmental information system (MEIS) to understand the land–sea interactions and provide data on the characteristics of the brackish water zone around the barrier islands. The MEIS was run in real time (1-s intervals) and made periodic marine observations (one to four times a year). The real-time data were largely obtained from a closed-circuit television and automatic weather stations using long-term evolution communication at two stations in March 2016. Since May 2015, the data have included periodic observations of surface sediment distributions (n = 90), the characteristics of suspended sediments in inlets and channel (n = 4), the brackish water zone environment during spring tide ebb and flood (n = 14, three lines), the seasonal variation in sedimentation along tidal flats (n = 29, three lines), and landscape classifications of the sub-environment (n = 30) in the barrier islands. The collected information includes real-time and a huge heterogeneous dataset characterized by multi-dimensional, multivariate, and spatiotemporal distribution variability. The system enables data management, and open access is necessary. The MEIS will enable effective estuary management and contribute to reducing the damage caused by natural disasters. Real-time prediction information has been integrated with environmental sensitivity index maps, which are provided using a geographic information system to enable a response strategy.

Comparisons of surface sediment distributions in summer 1997 and 2011 and elevations on the tidal flats in April 1998 and March 2013 had been used for understanding the long-term changes of sedimentary environments at southern Kanghwa tidal flat, west coast of Korea. The mud sediments dominated in the eastern part and sandy mud sediments dominated in the western part of the tidal flat in 1997. In 2011, the surface sediments were dominant mud and sandy mud at Sunduri and Tonggum in the eastern part, sandy mud at Tongmakri in the middle part, and sand and muddy sand at Yeochari and Changhwari tidal flats in the western part. The area of mud sediments had decreased, but that of sand-mud mixed sediments extended to eastward tidal flat for 14 years. The long-term topographic changes showed that deposition occurred at Tongmakri and Yeochari and erosion occurred at Changhwari tidal flat during 15 years. These changes should be effected the local hydrodynamic changes by several constructions near the tidal flat since the 1990s.

Lee, Y.G.; Kim, S.; Jeong, D.U.; Kim, J.K., and Woo, H.J., 2013. Effects of heavy rainfall on sedimentation in the tidal salt marsh of Suncheon Bay, South Korea. Tide observations, geographic surveys, sediment composition, and sediment accretion rate monitoring were conducted to investigate the relationship between general pattern changes and control factors of the accretion rate at 10 localities of the tidal salt marsh of Suncheon Bay over 2 years (June 2007–May 2009). The substrate sediments of the tidal salt marshes that are distributed between the mean sea level and the high water of ordinary spring tide are mainly composed of silt (37.98%) and clay (60.45%) and have a high average annual accretion rate of 28.88 mm/y. The high substrate sedimentation of tidal salt marshes is caused by: (1) a high concentrated suspended sediment supply from the tidal flat; (2) considerable marsh grass vegetation; (3) undeveloped tidal salt marsh creek; and (4) marsh elevation distributed between the mean sea l...

Maritime Security Research Center, Korea Institute of Ocean Science & Technology, Ansan P.O. Box 29,KoreaQuantitative understanding of total carbon, total inorganic carbon and total organic carbon contained in oceansediments is a basic data for interpretation of oceanic sediment environments. Elemental analyzer(EA) is frequentlyused for the analysis of carbon contents in inland soils and ocean sediments. Carbon and nitrogen contents of thesoil reference material analyzed by an EA were 2.30% and 0.21% with standard deviations of 0.02 and 0.01,respec-tively. Relative standard deviations were 0.01 and 0.06, respectively, representing a high precision. Regression anal-ysis of TOC and TC analysis results for the samples with TOC of less than 2.0% for the site in Hyung-Do showeda linear relationship with a slope of 0.9743(R

Background In situ air sparging (IAS) was undertaken at sites in the tidal flats of Mandol and Hajeon, on the west coast of South Korea, to estimate variations in the radius of influence (ROI). Results The Mandol core sample consisted of sand and muddy sand 1.6–3.4 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Phi$$\end{document}Φ (average 2.3 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Phi$$\end{document}Φ) and contained water (average 15.10 %). The Hajeon core sample consisted of muddy sand, sandy silt, and muddy sandy gravel 1.31–4.44 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Phi$$\end{document}Φ (average 3.11 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Phi$$\end{document}Φ) and contained water (average 19.77 %). These sites differ in their sedimentary and geochemical characteristics. At the Mandol site, no H2S or combustible gas was detected during a 48-h sampling period, except for some volatile organic compounds (0.1–2.0 ppm) at the monitoring well during the initial 30 min. At the soil vapor extraction wells, CO2 and O2 varied by 850 ppm (690–1540 ppm) and 0.5 % (20.4–20.9 %), respectively. At the Hajeon site, CO2 and O2 varied from 580 to 1250 ppm and 20.6 to 20.9 %, respectively, during the 48-h sampling period. Conclusions At the Mandol site, an oxygen concentration of 20.6 % was assumed as the effective concentration, and the ROI was estimated to be 128.0 cm. However, at the Hajeon site the ROI was estimated to be 85.7 cm. The smaller effective ROI at the Hajeon site was likely caused by the thin aquifer and thin screens of the sparing well. This estimated ROI show that the remediation effectiveness varies greatly as a heterogeneities and anisotropies in the porous sediments. Besides, injection pressure, flow rate, pulsing or continuous mode, and the range of intrinsic permeability for most important characteristic of sediment (soil) type impacted the ROI. Therefore, the IAS method is more effective at a pervasive air flow sediments such as Mandol, which consists of sand and muddy sand than at a channelized site such as Hajeon. Electronic supplementary material The online version of this article (doi:10.1186/s40064-016-3026-3) contains supplementary material, which is available to authorized users.

In coastal region, estuaries have dynamic conditions such as river discharge, tidal current, wave and sand ridge. These conditions generate suspended sediments processes in the estuary. Suspended sediment process can be used to explain reason for geological changes in the coastal area. To understand these processes, we use Geostationary Ocean Color Imager to monitor estuarine suspended sediments in this study. GOCI has high time resolution (1hour) and can provide daily SSC images. We compared daily GOCI SSC images with in situ SSC and conducted time-series analysis using monthly averaged GOCI SSC images. In dry season, net sediment fluxes were calculated. We can understand morphological changes in the estuary using these net sediment fluxes data. Using monthly averaged SSC images, the area influenced by river discharge in wet season can be explain. In the future, we will research about limitation of river discharge in wet season using optical satellite images.

Tidal channel networks are important factors influencing the morphodynamics of tidal flats and surface sedimentary facies. Here we investigate the relationship between channel distribution and sedimentary facies in Geunso Bay tidal flat, Korea. The tidal channel networks were extracted from a high spatial resolution aerial photograph, and for each sedimentary facies the pattern of tidal channel distribution was compared in terms of fractal analysis, channel density, and distance from the channel. The tidal channels in each sediment facies had relatively constant meandering patterns, but the density and complexity were distinguishable. The second fractal dimension was 1.87 in the mud flat, 1.41 in the mixed flat, and about 1.30 in the sand flat. The channel density was 0.036–0.06 m/m2 in the mud flat and 0–0.024 m/m2 in the mixed and sand flat areas. This implies that the tidal channels in the mud flat area represent a complex and dendritic pattern with high density compared to those in the mixed or sand flat areas. The results were used to test the applicability of adjusting sedimentary facies classification generated from interpolation of survey data. We quantitatively estimated the pattern of tidal channel distribution for each sedimentary facies based on a high spatial resolution aerial photograph. We suggest that tidal channel network features can be useful to surface sedimentary facies classification in tidal flats.

Since the 1980s, the coastal wetlands in Korea have been rapidly degraded and destroyed mainly due to reclamation and landfills for coastal development. In order to recover damaged coastal environments and to develop wetland restoration technologies, a 4-year study on ecological the restoration of coastal vegetated ecosystems was started in 1998. As one of a series of studies, a small-scale experiment on salt marsh restoration was carried out from April 2000 to August 2001. The experiment was designed to find effective means of ecological restoration through a comparison of the changes in environmental components and species structure between two different experimental plots created using sediment fences, one with and one without small canals. Temporal variation in surface elevation, sedimentary facies, and benthic species were measured seasonally in each plot and in the adjacent natural reference sites. Monthly exposure occurred from 330 cm to mean sea level, which represents the critical tidal level (CTL) at which salt marsh plants colonize. Vegetation, especially Suaeda japonica, colonized the site the following spring and recovered to a similar extent in the natural marshes 16 months later. The sedimentary results indicated that the sediment fences had effects on particle size and sediment accumulation, especially in the plot with small canals. This experiment also showed that tidal height, especially that exceeding the CTL, is an important factor in the recovery of the benthic fauna of salt marshes. From these results, we suggested that designs for the restoration of salt marsh ecosystems must consider the inclusion of a tidal height exceeding CTL, as this may allow reconstruction of the previous natural ecosystem without artificial transplanting.

High spatial resolution satellite data (IKONOS) combined with in situ data was used to quantitatively estimate the spatial distribution of tidal flat characteristics for the Hwangdo tidal flat, Cheonsu Bay, Korea. The classification result was accurate in terms of a comparison with the in situ data, and the overall accuracy was 90.7%, which confirmed the validity of the classification. GIS analysis based on a probabilistic model was applied to a quantitative estimation of the relationship between each surface sediment facies and the spectral reflectance. Mud flat facies showed a high positive correlation (R 2 = 0.91), and sand flat facies showed a high negative correlation (R 2 = 1.00), which was a good reflection of the sedimentary characteristics of Hwangdo tidal flat. Relationships between each sediment facies and DEM also showed good agreement with the topographic characteristics in the study area. The study revealed that intertidal surface sediment classification using high resolution remote sensing imagery and in situ data successfully shows spectral and topographic characteristics of the study area. It was noted that spectral reflectance was affected by a combination of environmental factors, including grain size, topography, and remnant surface water. It is possible to determine the type of tidal flat through quantitative estimates of the spatial distribution of surface sediments according to their spectral reflectance.

With the reduction of tidal currents by the closing of the Saemangeun 4th dyke, sedimentary environments on the Gunsan tidal flat, the nearest inner flat from the 4th dyke, has been severely changed, which might affect macrobenthic assemblages on the habitats. In order to investigate changes in macrobenthic community structure on Gunsan tidal flat, field surveys were seasonally conducted at seven stations from April 2002 to November, 2005. Sedimentary facies on the study area were shifted into muddominant facies. The fine sediment has been greatly deposited on the tidal flat with accumulation of organic materials after closing the water passage of 4th dyke section. These drastic variations in environments gave rise to change in macrobenthic community structure. Since the closure of the 4th dyke, the number of species of macrobenthos has gradually decreased. And the filter feeders and sand-favored species such as Urothoe convexa, Macrophthalmus dilatatus, Umbonium thomasi, and Mactra veneriformis have been replaced by the deposit feeders such as Macrophthalmus japonicus and Ilyoplax pingi. MDS ordination based on Bray-Curtis similarity from forth-root transformed species abundance data showed that the macrobenthic communities have passed through three succession stages from 2002 to 2005. During the third stage of 2005 opportunistic species such as Prionospio japonica, Heteromastus filiformis and Sinocorophium sinensis increased in population on the tidal flat.

Nine surface sediments from Masan Bay and Gadeog Channel were taken for grain size and geochemical and foraminiferal analyses in August 2002. The sediments consist of mud with 7.29-8.54 o in mean grain size. Average concentrations of Al, Fe and Mn are higher in Gadeog Channel than those in Masan Bay. On the other hand, average concentrations of Pb, Cu, Zn, Cd, Cr, Ni and V are higher in Masan Bay than those in the channel. The latter group of elements show the highest concentration at station M4, off the outfall of treated wastewater disposal. Eighty-one foraminiferal species are identified in total assemblages, including 21 species of living populations. The number of individuals, species number, species diversity and equitability in Masan Bay have lower values than those in Gadeog Channel. The foraminiferal fauna off the outfall is relatively poor. Compared to geochemical and foraminiferal data obtained in 1996, heavy metals are more enriched, and the characteristics of foraminifera are little changed. These features indicate that the pollution of Masan Bay has not been reduced.

The Saemangeum tidal flat with an area of approximately 233 ㎢ is one of the biggest estuarine tidal flats on the west coast of Korea. Because of its location in the estuary of Mangyeong and Dongjin Rivers, the tidal flat receives large amount of sediments. A 33-㎞ long sea dyke, enclosing a coastal zone of 401 ㎢, was constructed to reclaim tidal flat in the Saemangeum area. The dyke construction radically changes the local tidal current regime and estuarine circulation. These have an effect on sedimentary environments in the tidal flat. On the tidal flats of the study area net deposition occurred, but net erosion occurred near tidal channel in 2004. The comparison of topography and surface sediments in summer 2004 with those in summer 1988 before the dyke construction showed that elevation increased with maximum 80cm and mean grain sizes were fining at Gwanghwal tidal flats. Sedimentary facies of two cores from Gwanghwal tidal flat revealed homogeneous layers in the upper part, suggesting rapid deposition after the dyke construction. The sedimentation rate in Gwanghwal tidal flat(GW 6) using ²¹?Pb analysis was about 5.4 ㎝/yr, which is well matched with the sedimentation pattern revealed by change in topography.

The Saemangeum project is one of the biggest reclamation efforts in Korea and may cause coastal ecosystem change due to altered environments and habitat loss. Since February 2002, benthic environment and community structure in the Saemangeum subtidal area were studied to assess the influence of the project on macrofaunal community. The result of seasonal study from February, 2002 to August, 2005 is reported here. Overall, changes of species numbers and dominant species of benthic animals in the periods before (1988) and after (2002~2005) the Saemangeum dike construction were not evident both inside and outside the dike. However, local environmental and community change were noted. The partial completion of Saemangeum dike (4 th dike) in June 2003 altered water circulation and sediment deposition patterns both inside and outside the dike. Fine sediment was accumulated inside and outside the 4 th dike while coarse sediment dominated near the main channel (Sinsi gate). Benthic community responded to the altered sediment type in these areas. Species number and diversity in both site was low compared to other sites. The dominant species in these areas were composed of the benthos that had not commonly occurred in the Saemangeum subtidal area.

Six surface sediments from two offshore transects off Ulsan and Gampo, on the southeastern margin of Korea were taken for sediment and foraminiferal analyses. Sedimentary processes are dominated by reworking and resedimentation from storms in the area off Ulsan and hemipelagic suspension settling in the area off Gampo. Eighty-four foraminiferal species were identified in total assemblages, including 33 species of living populations and 9 species of planktonic foraminifera. The characteristics of foraminifera showed differences of offshore environments between Ulsan and Gampo. The number of living species, species diversity and equitability in Gampo offshore area had higher values than those in Ulsan offshore area. However, planktonic/benthic(P/B) ratio showed higher in the Ulsan offshore area. The species diversity indices and P/B ratio indicated that environmental stability and surface-ocean productivity in the Gampo offshore area were relatively higher than the Ulsan offshore area. The difference of species compositions is useful for interpreting the paleoenvironments in mud deposits of the southeastern margin of Korea.

Spatial and temporal changes around an area of conventional coastal engineering can be easily observed from field surveys because of the clear cause-and-effect observable in the before and after stages of the project. However, it is more difficult to determine environmental changes in the vicinity of tidal flats and coastal areas that are a considerable distance from the project. To identify any unexpected environmental impacts of the construction of Saemangeum Dyke in the area, we examined morphological changes identified by satellite-based observations through a field survey on Gomso Bay tidal flats (15 km from Saemangeum Dyke), and changes in the suspended sediment distribution identified by satellite-based observations through a hydrodynamic analysis in the Saemangeum and Gomso coastal area. We argue that hydrodynamic changes due to conventional coastal engineering can affect the sedimentation pattern in the vicinity of tidal flats. We suggest that the environmental impact assessment conducted before a conventional coastal engineering project should include a larger area than is currently considered.

The southern tidal flat of Kanghwa Island with an area of approximately is one of the biggest flats on the west coast of Korea. Surface sediments for sedimentary analyses were sampled at 83 stations in August 1997, September 1999 and August 2000. The very poorly-sorted mud sediments were predominant in the eastern part of the tidal flat, whereas the poorly-sorted sand-mud mixed sediments were dominant in the western part. The area of muddy sediment distribution diminished, but that of sandy mud sediment extended to southeastward tidal flat for three years. In the western part of tidal flat, deposition occurred during the period of spring to summer, whereas erosion occurred in winter. Sediment accumulation rates during three years indicated that the sediments deposited continuously in the eastern part of tidal flat, whereas eroded in the western part of tidal flat. Recently, construction of artificial structures such as new airport, island-connecting bridges and dikes near the tidal flat might change tidal current and river flow pattern. In order to reduce the ecological damage and to preserve tidal-flat environment, it is necessary to Investigate long-term impacts on sedimentary environment and ecology.

The seasonal patterns of sediment supply were investigated during the period of June 1999 to June 2000 on a coastal foredune of Seungbong Island, Korea. Sediment supply was determined from measurements of geomorphic changes in the foredune and beach along six lines. Most sands were deposited on the dunefoot and foredune area during the winter and spring, from November to April. The largest amount of sands was deposited along the lines 5 and 6 near the sea-dike in the southern tip of the dune area. In general, the sand on the beach was gradually eroded in spring, summer and fall but deposited in winter. Total sediment accumulation over the study period was for the foredune and for the beach. The volume of the foredune increased in the winter and spring, whereas the volume of beach increased in the winter. Variation in sediment deposition appears to be controlled primarily by variations in the seasonal wind regime.

Fine-grained surface sediments of the U.S. middle Atlantic coast contain pollen that are characteristic of the local vegetation. The pollen concentrations and pollen associations in lagoonal sediment appeared to be affected by physical characteristics of the landscape and the dynamic characteristics of the atmosphere and water. Arboreal pollen from the elevated mainland had a greater influence on uniform distribution of pollen in lagoons than arboreal pollen from the low profile barrier islands. The concentration of airborne pollen from the mainland decreased in a seaward direction across the lagoon. The maximum dispersion distance from the mainland was 7–10 km. Non-arboreal plants on the low profile barrier islands of the Virginia coast primarily provided pollen grains to the outer part of the coastal lagoon. The changes in pollen concentration and the relationship between arboreal and non-arboreal pollen documented in this study clearly differentiate into inner, middle and outer lagoon pollen spectra.

This paper proposes and tests a method of producing macrobenthos habitat potential maps in Hwangdo tidal flat, Korea based on an artificial neural network. Samples of macrobenthos were collected during field work, and eight control factors were compiled as a spatial database from remotely sensed data and GIS analysis. The macrobenthos habitat potential maps were produced using an artificial neural network model. Macrobenthos habitat potential maps were made for Macrophthalmus dilatatus, Cerithideopsilla cingulata, and Armandia lanceolata. The maps were validated by compared with the surveyed habitat locations. A strong correlation between the potential maps and species locations was revealed. The validation result showed average accuracies of 74.9%, 78.32%, and 73.27% for M. dilatatus, C. cingulata, and A. lanceolata, respectively. A GIS-based artificial neural network model combined with remote sensing techniques is an effective tool for mapping the areas of macrobenthos habitat potential in tidal flats.