• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.29 no.5
• /
• pp.727-743
• /
• 1996

To know the floristic composition, vortical distribution and community structure of marine benthic algae inhabiting in the intertidal and subtidal zones of Yongil Bay, east coast of Korea, the study has performed using the quadrat method along a transect line from July, 1995 to June, 1996. In this area, a total of 144 species including 2 new red algae to Korea was found: 5 blue-green, 18 green, 20 brown and 101 red algae. The representative species throughout the year were Ulva pertusa, Gelidium amansii and Symphyocladia latiuscula. Dominant species were Sargassum thunbergii in spring, U. pertusa in summer and autumn. In winter, Chondrus ocellatus and Monostroma grevillei occurred dominantly. The standing crop exhibited mean value as $185.8g/m^2$ dry weight. Maximum value was recorded in spring $(267.3g/m^2)$ and minimum was observed in winter $(93.7g/m^2)$. Shannon's species diversity (H') and evenness (J') as maximum value were recorded in spring, whereas minimum values were shown in winter. Vertical distribution, rerognized by cluster analysis based on relative coverage of the species, could be divided into two or three algal groups except spring. In general, green algae (M. grevillei, Capsosiphon fulvescens, U. pefusa, Enteromorpha compressa) and brown algae (Sargassum fulvellum, S. thunbergii) were represented in the upper and middle zone and red algae (G. amansii, C. ocellatus, S. latiuscula, Crateloupia okamurae, Pachymeniopsis eilliptica) in the lower zone. The algal community varied according to season and environmental conditions. Particularly, seasonal variation of vortical distribution seemed to be affected primarily by water temperature. Also seasonal tidal level and tolerance of algal species to desiccation appeared to be associated with it in this area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.7 no.2
• /
• pp.51-59
• /
• 2002

The seasonal variation in species composition and abundance distribution of zooplankton was studied in the Seomjin river estuary along the salinity gradients. In this estuary, marine taxa predominated in all seasons and very limited number of freshwater species appeared. The total abundances showed a seasonal fluctuation. The highest total abundance appeared in spring with over 3,000 individuals/m$^3$. In summer, the high abundance was sustained although it decreased a little. The abundance was minimal in fall with about 500 individuals/m$^3$. When the study area was divided into three salinity regimes, oligohaline (salinity less than 5 psu), mesohaline (5${\sim}$18 psu), and polyhaline zone (over 18 psu), the zone of high abundance as well as the composition of zooplankton community in each salinity regime changed seasonally. In fall, marine copepods predominated in oligohaline zone while marine species other than crustaceans dominated in polyhaline zone. However, in winter copepods predominated in all area. In spring and summer, holozoic dinoflagellate Noctiluca scintillans dominated in higher salinity regimes. We listed major copepod species of each salinity regime for each season with the ranges of water temperatures (T) and salinities (S) of their occurrence. T, S's of maximum abundances of those major copepod species were also reported. The observed very wide tolerance ranges of major copepod species for salinity suggested that the concept of 'indicator species' should be used in quantitative context rather than qualitative.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.18 no.1
• /
• pp.1-12
• /
• 2013

Acoustic backscatter profiles were measured by Eco-sounder along an east-west section in the mid-eastern Yellow Sea and at an anchoring station in the low salinity region off the Keum River estuary in September 2012, with observing physical water property structure by CTD. Tidal front was established around the sand ridge developed in 50 m depth region. Internal waves measured by Eco-sounder during low tide period in the eastern side of the sand ridge were nonlinear depression waves with wave height of 15 m and mean wavelength of 500 m. These waves were interpreted into tidal internal waves that were produced by tidal current flowing over the sand ridge to the southeast. When weakly non-linear soliton model was applied, propagation speed and period of these internal depression wave were 50 m/s and 16~18 min. Red tides by Dinoflagelates Cochlodinium were observed in the sea surface where strong acoustic scattering layer was raised up to 7 m. Hourly CTD profiles taken at the anchoring station off the Keum River estuary showed the halocline depth change by tidal current and land-sea breeze. When tidal current flowed strongly to the northeast during flood period and land-breeze of 7 m/s blew to the west, the halocline was temporally raised up as much as 2 m and acoustic profile images showed a complex structure in the surface layer within 5-m depth: in tens of seconds the declined acoustic structure of strong and weak scattering signals alternatively appeared with entrainment and intrusion shape. These acoustic profile structures in the surface mixed layer were observed for the first time in the coastal sea of the mid-eastern Yellow Sea. The acoustic profile images and turbidity data suggest that relatively transparent low-layer water be intruded or entrained into the turbid upper-layer water by vertical shear between flood current and land breeze-induced surface current.

• The Korean Journal of Malacology
• /
• v.24 no.2
• /
• pp.143-151
• /
• 2008

We studied the management policy for Haliotis diversicolor fisheries in the coastal area of Sungsanpo using Yield-per-recruit model from 2004 to 2006. The age at first capture($t_c$) and fishing mortality(F) annually estimated during the study period decreased and increased, respectively. The maximum yield-per-recruit in 2004 was increased by increasing $t_c$ from the 2.012 year of current $t_c$ to 2.7 year or increasing F from the 0.574/year of current F to 0.800/year, and that in 2005 was increased by increasing $t_c$ from the 1.946 year of current $t_c$ to 2.5 year or increasing F from the 0.578/year of current F to 0.880/year. In 2006, the maximum yield-per-recruit was increased by increasing $t_c$ from the 1.926year of current $t_c$ to 3.1 year or decreasing F from the 1.088/year of current F to 0.810/year. Further, although the current F in 2004 and 2005 was lower than the estimated $F_{MAX}$, that in 2006 was higher than the estimated $F_{MAX}$. These results indicate that the likelihood of growth overfishing with increasing catch of smaller H. diversicolor in 2006 was greater than in 2004 and 2005. As action that could prevent growth overfishing in fisheries management of H. diversicolor, increasing for the current $t_c$ could be a more appropriate policy because the artificial decrease of the number of woman divers related F is actually difficult.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.16 no.4
• /
• pp.196-205
• /
• 2011

To investigate the contribution of macroalgae to biogeochemical nutrients and carbon cycles, we measured the uptake rates of nutrients and $CO_2$ and characteristics of fluorescence of Saccharina japonica (Laminaria japonica Areschoug) using an incubation method in an acrylic chamber. From January to May 2011, S.japonica was sampled at Ilkwang, one of well-known macroalgae culture sites around Korea and ranged 46~288 cm long and 4.8~22.0 cm wide of whole thallus. The production rate of dissolved oxygen by S. japonica (n=25) was about $6.9{\pm}5.8{\mu}mol\;g^{-1}$ fresh weight(FW) $h^{-1}$. The uptake rate of total dissolved inorganic carbon ($TCO_2$), calculated by total alkalinity and pH, was $8.9{\pm}7.9{\mu}mol\;g^{-1}\;FW\;h^{-1}$. Mean nutrients uptake were $175.6{\pm}161.1\;nmol\;N\;g^{-1}\;FW\;h^{-1}$ and $12.7{\pm}10.1\;nmol\;P\;g^{-1}\;FW\;h^{-1}$. There were logarithmic relationships between thallus length and uptake rates of nutrients and $CO_2$, which suggested that younger specimens (<100-150 cm) were much more efficient at nutrients and $CO_2$ uptake than old specimens > 150 cm. There was a positive linear correlation ($r^2$=9.4) existed between the dissolved oxygen production rate and the $TCO_2$ uptake rate, suggesting that these two factors may serve as good indicators of S. japonica photosynthesis. There was also positive linear relationship between maximal quantum yield ($F_v/F_m$) and production/uptake rates of dissolved oxygen, $TCO_2$ and phosphate, suggested that $F_v/F_m$ could be used as a good indicator of photosynthetic ability and $TCO_2$ consumption of macroalgae. Maximum relative electron transport rate ($rETR_{max}$) of S. japonica increased as thallus grew and was high in distal part of thallus which may be resulted from the increase of photosynthetic cell density per area. The annual $TCO_2$ uptake by S. japonica in Gijang area was estimated about $1.0\sim1.7{\times}10^3C$ ton, which was about 0.02-0.03% of carbon dioxide emission in Busan City. Thus, more research should be focused on macroalgae-based biogeochemical cycles to evaluate the roles and contributions of macroalgae to the global carbon cycle.

• Korean Journal of Environmental Biology
• /
• v.23 no.2 s.58
• /
• pp.191-199
• /
• 2005

The community structure, vertical distribution and harpacticoids composition of the meiofauna community were observed from five stations in Marian Cove, King George Island and one station on the northeastern side of Nelson Island. Sample was taken by a free-fall corer in December 2002. Generally, 11 taxa of meiofauna were found, and meiofauna abundance ranged from 322 to 1575 indiv. $10cm^{-2}$ (mean 781 indiv. $10cm^{-2}$). Nematodes were the most dominant group, making up $89\%$ of total meiofauna, followed by harpacticoids $(6.8\%)$. Benthic harpacticoids appeared 19 species of nine families at all the stations, and most various taxa appeared at station B (13 species of seven families). For vertical distribution, more than $70\%$ of meiofauna was concentrated in the upper $0\~2cm$ sediment layers, and the density abruptly decreased with depth in all the stations. Total biomass of meiofauna varied between 41 and $360{\mu}gC\;10cm^{-2}$, and overall mean biomass was $205{\mu}gC\;10cm^{-2}$. Also nematodes had the highest percentage of total maiofauna biomass $(62.4\%)$. The analysis results of Canonical Correspondence Analysis between meiofauna community and sediment grain size showed that polychaets, oligochaets and cumaceans were influenced by silt&cray, and sand, granule and pebble had a influence on harpacticoids, kinorhynchs and ostracods respectively. But nematodes were not affected by sediment grain size.

• Journal of Fisheries and Marine Sciences Education
• /
• v.7 no.2
• /
• pp.182-200
• /
• 1995

Thirty two vessels of the Korean purse seiner had been operated in the Western Pacific Ocean for mainly skipjack tuna, Katsuwonus pelmis LINNAEUS and yellowfin tuna, Thunnus albacares BONNATERRE from January to December in 1991. Among them, fourteen vessels were chosen for this research. During the year their daily operated vessels totalled 4,153 vessels, their total casting net were 2,982 times, in caught 1,798 times, and their total catch was 106,300 M/T. We investigate the distribution of their catch by species, by body size, and by surfance water temperature, and also investigate the distribution of their catch by month and section of the sea, where the sections are separated by 30' of longitude and latitude from the monthly operated sea. We summarize these as follows : 1. The rate of catch by species is 75r/o skipjack tunas, 22.3% yellowfin tunas, and 2.7% bigeye and other tunas. 2. Of the caught skipjack tunas, those of weight 2.0~10kg are most and 68%, those of 1.5~8kg are 11.6%, and those of 3.0~8kg are 9.9%. Of the caught yellowfin tunas, those of weight 5~50kg and 10~50kg are most and 23.1%, and 28.3% respectively, those of 20~50kg are 15.8%, weight 30~50kg are 12.5%, and weight 2~50kg are 9.7%. 3. On the distribution of catch by surface water temperature, 49% of catch are taken between $29.0^{\circ}C$ and $29.4^{\circ}C$, 37% are taken between $29.5^{\circ}C$ and $29.9^{\circ}C$, and about 6% are taken between $28.5^{\circ}C$ and $28.9^{\circ}C$, but very little, only about 1% are taken below $28.4^{\circ}C$ and above $30.5^{\circ}C$. 4. On the distribution of catch by month and section of sea, skipjack tunas are most caught 10,618M/T in August and 10,412M/T in September in the section of Lat. $3^{\circ}{\sim}6^{\circ}S$ and Long. $174^{\circ}E{\sim}176^{\circ}W$, caught much 8,825M/I' in June and 8,057M/T in January in section of Lat. $1^{\circ}S{\sim}3^{\circ}N$ and Long. $142^{\circ}{\sim}151^{\circ}$E, but caught very little in May, November and December in the costal area of New Guinea. Yellowfin tunas are mostly caught 4,070M/T in June in the section of Lat. $0^{\circ}{\sim}4^{\circ}$N and Long. $142^{\circ}{\sim}151^{\circ}$E, and caught much over 2,000M/T in February~April and October~December in the section of coastal area and near islands, but caught very little in distant water area.

• Journal of the Mineralogical Society of Korea
• /
• v.32 no.4
• /
• pp.235-247
• /
• 2019

The Central South Sea Mud (CSSM), developed in the Seomjin River estuary, is known to be supplied with sediments from Heuksan Mud Belt (HMB) and Seomjin River. However, in order to form a mud belt, more sediments must be supplied than supplied in the above areas. Therefore, research on additional sources should be conducted. In this study, clay minerals, major elements analyzes were performed on cores 16PCT-GC01 and 16PCT-GC03 in order to investigate the transition in the provenance and transport pathway of sediments in CSSM. The Huanghe sediments are characterized by higher smectite and the Changjiang sediments are characterized by higher illite. Korean river sediments contain more kaolinite and chlorite than those of chinese rivers. Korean river sediments have higher Al, Fe, K concentraion than Chinese river sediments and Chinese rivers have higher Ca, Mg, Na than those of Korean rivers. Therefore, clay minerals and major elements can be a useful indicator for provenance. Based on our results, CSSM can be divided into three sediment units. Unit 3, which corresponds to the lowstand stage, is interpreted that sediments from Huanghe were supplied to the study area by coastal or tidal currents. Unit 2, which corresponds to the transgressive stage, is interpreted to have a weaker Huanghe effect and a stronger Changjiang and Korean rivers effect. Unit 1, which corresponds to the highstand stage when the sea level is the same as present and current circulation system is formed, is interpreted that sediments from Changjiang and Korean rivers are supplied to the research area through the current.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.5 no.3
• /
• pp.208-215
• /
• 2000

The estimated total material transports through the Cheju Strait using all data which investigated in 1997 and 1999 are as follows; A large amount of suspended sediments and dissovted inorganic nutrients are carried tothe South Sea through the Cheju Strait by a persistent eastward flow (Cheju Current) from the Y311ow Sea andthe East China Sea. The annual material Oanspous by the Cheju Current are as follows; 22.9${\times}$10$^6$ ton yr$^{-1}$(SS), 0.52${\times}$10$^{10}$ mol yr$^{-1}$ (NH$_4\;^+$), 6.05${\times}$10$^{10}$ mol yr$^{-1}$ (NO$_3\;^-$), 0.36${\times}$10$^{10}$ mol yr$^{-1}$ (PO$_4\;^{3-}$), 10.27${\times}$10$^{10}$ mol yr$^{-1}$ (Si(OH)$_4$). The annual suspended sediment flux per water transport in the Cheju Strait (44.48${\times}$10$^6$ ton yr$^{-1}$ Sv$^{-1}$) is about 1.7 larger than that in the Korean Strait (26.08${\times}$10$^6$ ton yr$^{-1}$ Sv$^{-1}$). The annual nitrate flux per water transport (11.60${\times}$10$^{10}$ mol yr$^{-1}$ Sv$^{-1}$) is about 1.2 larger than that in the Korean Strait (9.72${\times}$10$^{10}$ mol yr$^{-1}$ Sv$^{-1}$) and 2/3 of that by Kuroshio in the East China Sea (18.55${\times}$10$^{10}$ ton yr$^{-1}$ Sv$^{-1}$). It suggests that chemical rich Cheju Current will play a significant role in the biogeochemical processes in the South Sea where the huge land-based waste are introduced.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.9 no.3
• /
• pp.160-167
• /
• 2006

Harpacticoid copepod Tigriopus japonicus is widely distributed in coastal waters of Korea and plays important role in marine trophic structure as a first consumer. In this study, a series of experiment were conducted to test the potential of the species as a standard test species for marine bioassay. Tolerance on salinity and pH, sensitivity on the reference materials(copper sulfate and cadmium chloride) and response on the ocean dumping materials(waste sludge) we re tested to identify if the species satisfy the basic criteria as standard species for marine bioassay. The nauplius of the species($100{\sim}200{\mu}m$) showed wide tolerance on salinity with >90.0% survival rates exposed to $5.0{\sim}35.0psu$ for 48 h. Wide adaptability on pH's were also observed from 6.3 to 8.2 with >90.0% survival rates during the test. $LC_{50}$ values for copper sulfate and cadmium chloride were $3.6{\pm}0.7ppm,\;1.7{\pm}0.8ppm$, respectively. The variations in mortality between replicates were less than 10.0%. Comparison of $LC_{50}$ values indicated that T. japonicus nauplius was lower sensitive to copper sulfate than the most marine crustaceans included copepods, however, the sensitivity of test animal to cadmium chloride higher than the adults of copepod T. japonicus, Paracalanus parvus, and marine rotifer Brachinonus plicatilis. There were significant concentration-response relationship in the mortality of T. japonicus nauplius using the elutriates of three ocean dumping materials(industrial waste sludge). 48 h $LC_{50}$ values we re $31.1{\pm}1.1%$ for the elutriate of sludge from leather processing company and $54.4{\pm}15.1%$ for that of dye production company. Based on the above experimental results, bioassay using benthic harpacticoid T. japonicus nauplius must be a good estimation tool for marine ecotoxicological assessment of waste or chemicals. Wide tolerance on the salinity and pH, and significant linear relationship between concentration and response(mortality) supported the high potential of the species as a standard test species.