• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.4
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• pp.411-419
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• 2003

Dredged material during Masan Bay cleaning in 1990-1994 was deposited in Gapo area. The site provides an ideal experimental condition to monitor environmental remediation and benthic ecosystem stabilization processes after the disturbance. Sea water samples were taken during one tidal cycle in one hour interval from Oct. 2001 to Apr. 2002 (4 times) to estimate the organic matter and nutrient fluxes in Gapo area. Hourly material fluxes were estimated from the water balance estimated from 3 dimensional topography of Gapo area and from material concentration. Net material fluxes were estimated from the difference between total influx and total outflux during one tidal cycle. Chemical oxygen demand showed net outflux in Nov. 2001, Dec. 2001 and Apr. 2002 (2.2∼3.9 g m$\^$-2/ h$\^$-1/) and showed net influx in Mar. 2002 (1.4 g m$\^$-2/ h$\^$-1/). Ammonium showed net outflux during the study (0.1∼118 mg m$\^$-2/ h$\^$-1/m-2h-I). According to this investigation, Gapo area was a source rather than a sink of organic matter. However, the variability of the material fluxes was high so that a long term study may be required.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.617-636
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• 2015

The Mokpo coastal waters receive discharges from three artificial lakes(Youngsan, Youngam, Geumho) and other terrigenous freshwater inflows(streams, sewage treatment effluent, fresh groundwater), which exhibit very high concentrations of nutrients and/or organic matters. To understand spatial distributions of nutrients(DIN, DIP, DSi) and other water quality parameters(Chl-a, water temperature, salinity, DO, COD, SS), field surveys were conducted at 10 stations in the Mokpo harbor and adjacent estuaries on May, July, September, and November 2008 within 10 days following discharge events from artificial lakes. In this study, the freshwater flow rate influxed by the operation of sea dike sluice had significant influence on water qualities of the Mokpo coastal waters, although nutrient concentrations in other freshwater sources such as streams, sewage treatment effluent, and fresh groundwater were much higher. As a result of statistical analysis, DIN, COD, and Chl-a had a negative correlation with salinity. Therefore it was shown that discharge extents, time, and nutrients from the Youngsan lake were major impact factors dominating the spatial characteristics of nutrients and other water quality parameters in the Mokpo harbor and adjacent waters. However, despite non-discharge from the Youngsan Lake on September of this investigated period, it was observed that the nutrient addition was taking place in the lower layer of the estuary suggesting nutrient supply through different pathways. This result has emphasized the need to implement the combined assessment about the cumulative impacts on the Youngsan Estuary environment and ecosystem due to freshwater inputs derived from the artificial lakes as well as other terrigenous inflows, or benthic releases.

• Journal of the Korean Society for Marine Environment & Energy
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• v.20 no.1
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• pp.12-17
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• 2017

This study established ecological goals and success criteria by using results of the coastal ecosystem restoration demand survey. The ecological goals are set for species diversity, regulation of seawater flow, improvement of purification, erosion prevention and habitat provision by ecosystem types. The indicators of success criteria are chosen the number of emergence species and community characteristics of target organism and pertinent items of hydrologic, water quality and sediment environment by ecological goals among the investigation items of tidal flat investigation guideline.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.30-37
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• 2012

This paper assessed environmental impact of tidal power plant construction in the western sea of Korea, and diagnosed problems of the related assessment. We also proposed key assessment items (scoping) and system improvement for environmental impact assessment (EIA). The establishment of a broad consensus of the appropriateness and a clear purpose for business is an important aspect of the aptness of using the waters, and the aggressive collecting of opinions of the stakeholder and institutions will have to be fulfilled. In addition, we presented the following scoping plan in order to minimize the negative effects of the marine ecosystem and the conflict between the people who work in the fishing industry which result due to the construction of the tidal power plants. (1) the change in seawater exchange rates and the aspect of erosion/sedimentation which result from the change in the velocity of running fluid, (2) the destruction of spawns/habitats of fish due to the damage of tidal flats, (3) fishery resources, impacts of fishing grounds, and the spread of suspended sediments, etc. will have to be applied to the key assessment items(scoping). In addition, every citizen will have work hard for an establishment of an active plan which achieves the harmony and balance of environmental preservation and for the policy to be applied through changing their consciousness of environmental preservation.

• Journal of Wetlands Research
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• v.21 no.2
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• pp.95-101
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• 2019

In tidal flats that lack plants, methane ($CH_4$) fluxes are both positive (gas emission) and negative (gas "sinking") in nature. The levels of methanotroph populations significantly affect the extent of $CH_4$ sinking. This preliminary study examined $CH_4$ flux in tidal flats using a circular closed-chamber method to understand the effects of macroinvertebrate burrowing activity. The chamber was deployed over decapods (mud shrimp, Laomedia astacina and crab, Macrophthalmus japonicus) burrows for ~ 2 h, and the $CH_4$ and $CO_2$ concentrations were continuously monitored using a closed, diffuse $CH_4/CO_2$ flux meter. We found that Laomedia astacina burrow (which is relatively long) site afforded higher-level $CH_4$ production, likely due to diffusive emission of $CH_4$ in deep-layer sediments. In addition, the large methanotrophic bacteria population found in the burrow wall sediments has $CH_4$ oxidation (consumption) potential. Especially, nitrite-driven anaerobic oxidation of methane (AOM) may occur within burrows. The proposed $CH_4$-oxidation process was supported by the decrease in the ${\delta}^{13}C$ of headspace $CO_2$ during the chamber experiment. Therefore, macroinvertebrate burrows appear to be an important ecosystem environment for controlling atmospheric $CH_4$ over tidal flats.

• Korean Journal of Agricultural Science
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• v.32 no.2
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• pp.107-126
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• 2005

The most limited production resource in Korea is land. During the period from 1995 to 2002, annual farm land area of 17,600ha have been converted to urban and industrial land. The self-sufficiency rate of rice, Korean staple food, is expected to be decreased from 97.5% in 2003 to 60-70% in 2020. Under such conditions, this study is aimed at first identifying multi-functional benefits of the reclamation projects such as agricultural production, industrial water supply, urban land supply, transportation effects, sightseeing effects and environmental values with and without the projects. To carry out the objectives, three existing tideland reclamation projects such as Daeho, Kumgang and Yongsangang irrigation project stage II were evaluated and Saemangeum tideland reclamation project which was jointly revaluated by environmental NGO and Govn't appointed specialists in 2000 was reviewed. According to this study results, tide land reclamation projects were showed financially and economically feasible and environmentally sustainable. The joint cost like estuary dam should be allocated based on the multi-functional benefits of the projects. To allocate the joint cost, legal and institutional improvement should adapt the joint cost allocation method as the specific cost-remaining benefit method. Korea has more than 402,000 ha of tidal flat of which 76,396ha have been reclaimed in 2003. To meet food security and to cope with shortage of land, phil-environmental reclamation projects should be continuously implemented and necessary tidal flats for protecting environmental ecosystem should be remained according to the detail survey results of reclaimable resources.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.2
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• pp.49-67
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• 2006

A mesocosm, an artificial tidal flat ecosystem, was constructed outdoors to simulate in situ physical and biochemical environmental conditions of natural tidal flat as much as possible. During the experiment from February to August 2004, the study was focused on the biogeochemical variations of superficial water and porewater after introduction of freshwater into the mesocosm. The mesocosm has three experimental conditions; SW-M-T: maintaining the saline water of approximately 20 psu; FW-M-T: complete exchange of freshwater ul the mesocosm with continuous mixing of water column: FW-NM-T: complete exchange of saline water to freshwater in the mesocosm without mixing of water column. Mass extinction of benthic macrofauna appeared due to drastic decrease of porewater salinity from 20 psu to less than 10 psu between the 63th and 91st day of freshwater introduction in FW-M-T and FW-NM-T. Throughout the periods, 7/8 of bivalves and 2/3 of polychaete populations have been extinguished in the sediment. In FW-NM-T, as temperature rises, both evident decrease of DO in water column and active release of DIP from sediment were observed. ${NO_3}^-$ was removed from water column into sediment throughout the periods. Therefore extremely low ${NO_3}^-$ was found during late spring and summer. Whereas ${NH_4}^+$ exhibited only $1/2{\sim}1/8$ of ${NO_3}^-$ concentration. Unexpectedly even after mass extinction of benthic macrofauna, we were not able to find high ${NH_4}^+$. This mesocosm study suggests that when fresh water introduce to natural tidal flat, its sediment activity functions as a potential source of DIP, but a sink of ${NO_3}^-$.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.65-70
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• 2015

We have found the plants belonging to the genus Spartina which has not yet been reported for the flora of Korea. This has been distributed at Dongmak seashore in Ganghwado since 2012. These were identified as common cordgrass (Spartina anglica C. E. Hubb.) belonging to the family Poaceae, the genus Spartina. It is a perennial halophyte as an alien weed that can grow in the tidal flat, native to southern England. Here, we named it for 'Young-guk-Gaet-ggeun-pool' in Korean refer the origin, reported the distribution, spreading condition, and botanical characteristics of common cordgrass. In China, Spartina anglica was introduced in 1963, it was approved that it had benefit in a bioengineering side firstly. But it was known that as a highly invasive plant to make a monotype meadow of Spartina anglica which has deteriorate the ecological function of saltmarsh. And also it has another problem that is not easy to eradicate. The spreading of Spartina anglica which was appeared in the West coast of Korea may threaten severely to the domestic mudflat and estuary ecosystem. For the maintenance of mudflat ecosystem soundly, continuous monitoring and active eradication plans are required.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.2
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• pp.16-27
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• 2003

For the last decade, some 400 small and large oil spill accidents have occurred every year. Such accident blow a serious damage to the marine resource and ecosystem, which can't be estimated in terms of economic and environmental losses. The physical/chemical methods used currently may be effective at the initial stage of accidents, but they can't serve to remove the spilled oil completely. Moreover, the dispersant may lead to a secondary contamination detrimental to the lives inhabiting wet lands, beaches and tidal zone. Thus, a new decomposing technology Is required for the environmentally sensitive areas. Bioremediation is the active use of biological techniques to mitigate the consequences of a spill using biological processes and refers both of stimulation of pollutant biodegradation and/or to enhance ecosystem recovery Bioremediation is an economically attractive method for the clean-up of oil-contaminated area. Bioremediation has been demonstrated to be an effective oil spill countermeasure for use in cobble, sand beach, salt marsh, and mud flat environment.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.1
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• pp.160-169
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• 2019

The migration status of waterbirds inhabiting the 10 coastal wetlands in the south and west coasts (Jangbongdo, Muuido, Daecheoncheon estuary, Seocheon tidal flat, Yubudo, Gomso bay, Hauido, Jeungdo, Doam bay, Gangjin bay) was examined from May 2008 to March 2013. For the most dominant taxonomical group, shorebirds accounted for 37.5% of the number of species and 67.1% of the total population, followed in the order of dabbling ducks, herons, and seagulls. The dominate species were Calidris alpina, Larus crassirostris, Limosa lapponica, Charadrius alexandrinus, and Calidris tenuirostris. Shorebirds were observed most at Seocheon Tidal Flats and Yubudo Island, and dabbling ducks were found most in Doam Bay. Diving ducks were observed most at Gangjin Bay and seagulls were seen most frequently at Seocheon Tidal Flats. The ten coastal wetlands of the western and southern coasts were divided into three groups according to the similarity index of waterbirds (Ro). Group 1 was the area where dabbling ducks and diving ducks were dominant, group 2 was the area where shorebirds were dominant, and group 3 was the area where seagulls were dominant. It was evident that there were differences in species composition depending on the regional environments.