• Journal of Korean Society for Atmospheric Environment
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• v.16 no.4
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• pp.415-420
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• 2000

The daily mean concentrations of PM2.5 mass ionic species carbonaceous species and HNO3, HCl, and NH3 were analyzed at three background sites in Korea : Kangwha, Kosan, and Dongbaik during two intensive field studies between December 1996 and January 1997, Four-day backward trajectory analysis was also carried out. The mean concentrations of anthropogenic species were higher at Kangwha and Dongbaik than Kosan. At these two sites themean concentrations of nitrate and ammonium/ammonia were higher than those of Kosan. It was suggested that these two sites be considered as the background sites of the Seoul Metropolitan Area and Pusan respectively. Major chemical components in fine particles were sulfate organic carbon nitrate and ammonium for all the sites. More than 90% of sulfate were non-sea-salt(nss) sulfates and most of the nss sulfate in PM2.5 might be present as ammonium sulfates at all sites. Most of air parcels arriving a Kangwha and Dongbaik were from the northern China. At Kosan during the measurement period half of air parcels were from the northern China and the other half from the southern China. At Kosan the concentrations of anthropogenic air pollutants originated from the southern China were higher than those typically observed from the northern China.

• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.268-277
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• 2019

Severe damages will result in human society, when several different critical natural phenomena coincide. One example relates to the resting cysts of Alexandrium species (dinoflagellates that cause paralytic shellfish poisoning), which are preserved in surface sediments throughout Osaka Bay, Japan. These cysts have been found to accumulate particularly densely in shallow areas in the inner parts of Osaka Bay, where a tsunami caused by an earthquake could occur any time. Damage by a tsunami could cause a change of the coastal ecosystems at Osaka Bay including the resuspension of surface sediments containing resting Alexandrium tamarense cysts and the subsequent redistribution of the cysts in newly deposited sediment. Under certain environmental conditions, these cysts could germinate and form dense blooms, leading to paralytic shellfish poisoning. Such a scenario could also affect other coastal areas, including the southern coast of the Korean Peninsula.

• Journal of fish pathology
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• v.19 no.3
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• pp.215-225
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• 2006

Viral and bacterial pathogens of the wild marine fishes were monitored in 176 wild fish and 15 wild shrimp from 13 and 1 species, respectively, which were captured by a trawl net in the southern sea of Korea during June 2006. Viral pathogens that are common etiologically agents to cultured fish in Korea were not isolated. One and 5 bacterial strains were affiliated to the genus Proteus and Pseudomonas, respectively, but these bacteria do not seem to be associated with mortality of aquacultural fish. An extended monitoring on wild marine fishes were necessary for identification of agents responsible for the cultured fish infections.

• Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.167-171
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• 1999

This study was designed to develop biomarkers of coastal pollution using biochemical indices of flounder (Paralichthys olivaceus) by changes in lactate dehydrogenase (LDH) activity in the serum and cholinesterase activities in brain membranes. For this purpose acetylcholiesterase (AChE) activity, butyrylcholinesterase (BChE) activity, LDH/AChE ratio and LDH/BChE ratio of cultured flounders at 5 different sites on the southern coast of Korea were compared to those of wild flounders caught in the Pohang, eastern coast of Korea as a control group. Relatively high LDH activities were measured in the serum of flounders cultured on the southern coast of Korea (0.101-0.145 unit) than those in the Pohang control group (0.093 unit). AChE activities were significantly low $(about\;10-20\%)$ in brain membranes of cultured flounders compared to those in the Pohang control group. The ratios of LDH/AChE and LDH/BChE were consistently higher $(136-178\%,\; 155-214\%)$ in cultured flounders than those of Pohang control group. Thus, we propose that the ratios of LDH/AChE and LDH/BChE in flounders could be applicable for the diagnosis of marine pollution.

• Animal Systematics, Evolution and Diversity
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• v.33 no.1
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• pp.8-16
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• 2017

We firstly described a box jellyfish, Carybdea brevipedalia collected from the southern coasts of Korea. It is morphologically characterized by gastric phacellae, a special digestive system of cubozoan jellyfish, and velarium, the thin muscle flap forming the opening of the subumbrellar cavity. The phacellae are linear-shaped, comprising numerous cirri branched from multiple roots. Each root also has multiple numbers of cirrus bundles. Basis of velarial cannels parts into two branches in each octant of velarium. Its geographic distributions were limited to Jeju-do and the middle-southern coasts where the organisms are seriously hazardous to bathers in summer. Numerous individuals and/or large-sized populations were observed specifically from beaches at Jeju-do, Namhae-do and a small fishing port of Namildae, while only a small amount of the individuals was observed in Gamak Bay, Jaran-Goseung Bay, and Geoje-do. We confirmed molecular identity of the Korean C. brevipedalia with comparison of nuclear ribosomal DNA sequences. Until now, Carybdea brevipedalia is the only cubozoan species reported to be distributed in Korean waters.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.291-299
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• 2006

The observed ocean barotropic circulation is not completely explained by the classical wind-driven circulation theory. Although it is believed that the thermohaline forcing plays a role in the ocean barotropic circulation to some degree, how much the thermohaline forcing contributes to the barotropic circulation is not well known. The role of thermohaline circulation driven by changes in temperature and salinity in the Southern Ocean (SO) water masses on the Antarctic Circumpolar Current (ACC) transport is investigated using a coupled ocean - atmosphere - sea ice - land surface climate system model in a Last Glacial Maximum (LGM) context. Withthe implementation of glacial boundary conditions in a coupled model, a substantial increase in the ACC transport by about 75% in 80 years of integration and 25% in the near LGM equilibrium is obtained despite of the decreases in the magnitude of wind stresses over the SO by 33% in the transient time and 20% in the near-equilibrium. This result suggests that the increase in the barotropic ACC transport is due to factors other than the wind forcing. The change in ocean thermohaline circulation in the SO seems to play a significant role in enhancing the ACC transport in association with the change in the bottom pressure torque.

• Ocean and Polar Research
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• v.27 no.2
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• pp.231-235
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• 2005

The European Iron Fertilization Experiment EIFEX studied the growth and decline of a phytoplankton bloom stimulated by fertilising $10km^2$ in the core of a mesoscale $(80{\times}120km)$ cyclonic eddy south of the Antarctic Polar Front with about 2 times 7 tonnes of iron sulphate. The phytoplankton accumulation induced by iron fertilization did not exceed $3{\mu}g\;chl\;a\;l^{-1}$ despite a draw down of $5{\mu}M$ of nitrate that should have resulted in at least double to triple the amount of phytoplankton biomass assuming regular Redfield-ratios for draw down after phytoplankton growth in the Southern Ocean. During EIFEX the fertilized core of the mesoscale eddy evolved to a hotspot for a variety of small and medium sized mesozooplankton copepods. In contrast to copepods, the biomass of salps (Salpa thompson)) that dominated zooplankton biomass before the onset of our experiment decreased to nearly extinction. Most of the species of the rnosozooplankton community showed extremely hiか feeding rates compared to literature values from Southern Ocean summer communities. At the end of the experiment, massive phytoplankton sedimentation reached the sea floor at about 3800m water depth.

• Ocean and Polar Research
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• v.24 no.3
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• pp.189-196
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• 2002

A multichannel seismic survey was conducted in the southern Ayu Trough which is the only spreading boundary between the Philippine Sea and Caroline plates. The seismic system used in this study comprises of 2.46-l sleeve gun and a 12-channel streamer with a group interval of 6.25m. Migration technique was used to analyze seismic velocity, and poststack depth migration was applied to the stacked data. The sediment thickness obtained from the depth section tends to increase with distance from the spreading axis. Sedimentation rates are poorly constrainted in the study area. The apparent half-spreading rates estimated from the sediment thickness and sedimentation rate from DSDP hole on the caroline plate are 4.7mm/yr and 7.9mm/yr at $1^{\circ}24'N\;and\;0^{\circ}42'N$, respectively, which are fester than Previously suggested. On the basis of new oblique spreading geometry, the recalculated spreading rates are 5.4mm/yr and 9.1mm/yr at $1^{\circ}24'N\;and\;0^{\circ}42'N$, respectively. Seismic sections show that the topography is asymmetric across the Ayu Trough and the acoustic basement is rough. These features are consistent with the earlier suggestion that the Ayu Trough is a slow-spreading divergent boundary. A detailed examination of seismic profiles away from the axis shows that sediments can be divided into two layers which implies a possible change in the spreading rate anuor sedimentation condition during the formation of the trough.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.295-301
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• 2011

We investigated the genetic structure of Korean and Japanese ayu Plecoglossus altivelis populations by examining 669 individuals from 14 populations using three microsatellite loci. Genetic variation did not differ significantly among the populations examined in terms of allelic number and heterozygosity. Korean populations were genetically close to each other, implying that persistent gene flow has occurred in these populations. This suggests that eastern populations in Korea form a single large population and all of the Korean populations are distinct from the Japanese populations. Pairwise population $F_{ST}$ estimates, principal component analyses, and a neighbor-joining tree showed that genetic separation between the southern and pooled eastern coast populations was probably influenced by restricted gene flow. Hierarchical analysis of molecular variance (AMOVA) revealed a weak but significant genetic structure among three ayu groups (eastern and southern coasts of Korea and the Japan coast), and no genetic variation within groups. The estimated genetic population structure and potential applications of microsatellite markers may aid in the proper management of ayu populations.

• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.37-42
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• 2001

The biomass of Ulva mats was surveyed in a lower rocky shore of the southern coast of Korea during the 1998-1999 winter. The population selected for the present study was located on the tidal zone ranging from 118 cm to 130 cm below mean sea level (MSL), where abundance of Ulvu species was highest. The biomass of Ulva species increased gradually from December 1998 until February 1999, reaching the maximum of 374 g dry wtㆍm$^{-2}$ in February. The biomass varied little among the sampling quadrats for each sampling time. Over the course of the study a total of 16 taxa were sampled from Ulva mats, of which 5 were macrophytes and 11 were macroinvertebrates. Rodophyta comprised 3 taxa, followed by Phaeophyta of 2 taxa, but there was no Chlorophyta except for Ulva species. The macrofaunal assemblage was consisted of 8 taxa of Mollusca, 2 Arthropoda and 1 Annelida. There was a dramatic increase in Mytilus sp. in February. Moreover, the trend of biomass were similar between some macroinvertebrates and Ulva species. The results suggested that macroinvertebrates may play an important role in nutrient dynamics as well as food web. Further experimental evidence may be necessary to explain the correlation between Ulva mats and abundance of coexisting macroinvertebrates.