• ALGAE
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• v.23 no.3
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• pp.241-250
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• 2008

Since seagrasses in the coastal and estuarine ecosystems achieve high levels of production, they require high inorganic carbon and nutrient incorporation. Thus, seagrasses may play a significant role in carbon and nutrient cycling in the coastal and estuarine ecosystems. To examine growth dynamics of Zostera marina L. environmental factors such as underwater irradiance, water temperature, and salinity, and biological parameters such as shoot density, biomass, shoot morphology, and leaf productivity were measured in two bay systems (Jindong Bay and Gamak Bay) on the southern coast of Korea. While underwater irradiance did not show distinct seasonal trend, water temperature at both sites exhibited clear seasonal trend throughout the experimental period. Shoot density increased dramatically during winter due to the increased seedlings through germination of seeds in Jindong Bay and due to the increased lateral shoots in Gamak Bay. Eelgrass biomass increased during winter and decreased during summer. Maximum biomass in Jindong Bay and Gamak Bay was 250.2 and 232.3 g dry weight m–a2, respectively. Carbon incorporation into the eelgrass leaf tissues was estimated from productivity and leaf tissues carbon content. The calculated annual carbon incorporations at the Jindong Bay and Gamak Bay sites were 163 and 295 g C m–`2 y–`1, respectively. This high carbon incorporation into seagrass tissues suggests that seagrass habitats play an important role as a carbon absorber in the coastal and estuarine ecosystems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.37-44
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• 1998

Feeding habits of Pseudoblennius cottoides collected from the eelgrass bed in Kwangyang Bay from January 1994 to December 1994 were studied. Pseudoblennius cottoides was a carnivore which mainly consumed fishes, caridean shrimps, and amphipods. Its diets included small Quantities of tanaids, copepods, isopods, mysids, and polychaetes. It showed ontogenetic changes in feeding habits. Fishes were heavily selected as the body size of P. cottoides increases. Fishes and caridean shrimps were major prey organisms for all seasons.

• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.431-438
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• 2009

The main purpose of this research is to prepare and provide basic materials for the propagational strategy of eelgrass by investigating on the morphological adaptation of Korean Zostera marina to ocean currents. An eelgrass plant mainly consists of rhizome, leaf sheath, leaves and roots. The rhizome is the horizontal stem of the plant that serves as the backbone from which the leaves and roots emerge. The leaf sheath is the bundle at the base of the leaves that holds the leaves together, protecting the meristem, the primary growth point of the shoot. Leaves originate from a meristem which is protected by a sheath at the actively growing end of the rhizome. As the shoot grows, the rhizome elongates, moving across or within the sediment, forming roots as it progresses. The aggregated leaves from the leaf sheath are found to have two cell layers on one side and multiple layers of airy tissues called aerenchyma on the other. The aerenchyma tissues are developed in multi-layered cell structures surrounding the veins which are formed in the leaf sheath. Generative shoots are made of rhizomes, which are circular or ovoidal, stem, and spathe and spadix. The transverse section of rhizome and the stem and central floral axis is found to be circular, ovoid and in the shape of convex respectively, and the vascular bundle, which is a part of transport system, has one large tube in the center and two small tubes on both sides. The layers of collenchyma cells numbered from 12 to 15 in the stem, and from 7 to 12 in the rhizome. The seed coat is composed of sclereids, small bundles of sclerenchyma tissues, which prevent the influx of sea water from the outside and help endure the environmental stress. In conclusion, alternative multi-layer structure in circular, convex type aggregated leaf base are interpreted to morphological adaption as doing tolerable elastic structure through movement of seawater. The generative shoots develop long slim stem and branches in circular or ovoidal shapes to minimize the adverse impacts of sea current, which can be interpreted as the plant's morphological adaptation to its environment.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.4
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• pp.343-355
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• 2021

Eelgrass, Zostera marina L., was widely distributed around Sinyangseopji Beach in Bangdu Bay, on the eastern coast of Jeju Island, until breakwater construction in the late 1990s resulted in its complete loss. Six experimental sites were identified for restoration of the Z. marina bed in Bangdu Bay. Using the staple method, 500 Z. marina shoots were transplanted at each site in January 2019 and 2020. The transplants, along with environmental parameters, were monitored for 10 months following transplantation. There were significant differences in underwater irradiance, water temperature, and salinity among the sites, but all were suitable for Z. marina growth. The Ulva species, an opportunistic alga, appeared in spring and accumulated during summer at all sites; however, there was no significant effect of Ulva species on the survival and growth of the eelgrass transplants. Most of the transplanted Z. marina survived, and after 3 months, the density increased by 112.5-300% due to vegetative propagation, with a rapid rate of increase observed during spring and early summer at all sites. For 1-2 months after transplanting, the Z. marina shoots showed signs of transplant shock, after which the shoot density increased at all sites, confirming that all transplants adapted well to the new environment. However, in both 2019 and 2020, during late summer to early fall, the sites experienced heavy damage from typoons (twice in 2019 and three times in 2020) that hit Bangdu Bay. The transplants at two sites located in the center of Bangdu Bay were completely destroyed, but those at three sites located to the west of the bay showed a 192-312% increase in density. Thus, we confirmed that the Bangdu Bay Z. marina bed can be restored, with the highest probability of success for Z. marina restoration on the western side of Bangdu Bay, which is protected from typhoons.

• Korean Journal of Ichthyology
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• v.24 no.1
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• pp.11-19
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• 2012

Seasonal fish species composition in the sandy shore adjacent to eelgrass bed was determined. Monthly samples were collected by a beam trawl from August 2009 to July 2010. A total of 38 species, 1,232 individuals and 5,277.7g of fishes were collected. The dominant species were $Favonigobius$ $gymnauchen$, $Takifugu$ $niphobles$, $Hypodytes$ $rubripinnis$, and $Rudarius$ $ercodes$. These four dominant fish accounted for 73.2% of the total number of individuals, and 53.9% of the biomass of collected fish. During the survey, the water temperature ranged from 11 to $25^{\circ}C$, and the salinity ranged from 29 to 35 psu. The monthly species diversity index showed the lowest value of 0.89 in March and highest value of 2.35 in June 2010. Fish species composition and abundance in Myeongsa sandy shore, were similar to that the adjacent eelgrass bed, but were different from those of Gujora sandy shore open the sea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.5
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• pp.461-467
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• 2014

The growth and production of Pseudoblennius cottoides (1.80~10.01 cm TL) were investigated in an eelgrass bed of Dongdae Bay, Korea throughout 2006. A total 702 P. cottoides were collected with a small beam trawl. Growth in fish total length was expressed as: $TL=0.0539d^{0.9105}$. The relationships between total length body weight was estimated as $W=0.0079TL^3.1103$. The densities, biomass, daily, annual production, and P/B ratio were $0.06{\pm}0.062/m^2$, $0.10{\pm}0.144g/m^2$, $0.0005{\pm}0.0006g\;AFDW/m^2/day$, $0.1833g\;AFDW/m^2/year$, and 1.813, respectively. Monthly production of P. cottoides were greatly peak in May, July and September (0.0029, 0.0031 and $0.0019g\;AFDW/m^2/day$) when the biomass was high, and the lowest value in December (0.00004g AFDW/m^2/day) when the biomass was low. Monthly change in production of P. cottoides was positively correlated with biomass and temperature.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.2
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• pp.176-182
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• 2016

The feeding habits of juvenile Chaenogobius annularis were examined based on gut content analysis of 281 individuals, collected from May to June 2011 in the coastal water of Geoje, Korea. Copepods were the main source of food for C. annularis, which constituted 61.6% in IRI. Barnacle larvae was the second largest dietary component. Graphical analysis of the diet composition showed that C. annularis was a specialized predator characterized by strong individual feeding specialization. Both small and large size class of C. annularis mainly consumed harpacticoida and cirripedia cypris.

• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.22-29
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• 1997

Feeding habits of Pholis nebulosa collected from a eelgrass bed in Kwangyang Bay from January 1994 to December 1994 were studied. Pholis nebulosa was a carnivore which mainly consumed epiphytal amphipods. Its diets included minor quantities of caridean shrimps, isopods, copepods, tanaids and polychaetes. It showed ontogenetic changes in feeding habits. In an initial feeding stage, copepods were major food organisms. However, gammarid and caprellid amphipods were heavily selected with increasing fish size. Although gammarid and caprellid amphipods were major prey organisms for all seasons, the relative proportion of these two food items changed with season.

• Journal of Marine Bioscience and Biotechnology
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• v.13 no.1
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• pp.58-65
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• 2021

In 2012, fishes caught by three-side fyke net in the coastal waters of Jedo were assessed for species composition and seasonal fluctuation in their abundance. The fish were caught at two research stations (St.) and were found to comprise 53 species, 39 families, and 9 orders. The dominant species were Takifugu niphobles, Lateolabrax maculatus, and Acanthopagrus schlegelii. To gain a measure of their biodiversity, all the species were assessed for their number, richness, diversity, evenness, and dominance. The highest and lowest number of total caught fish individuals was recorded in summer and winter, respectively. The diversity index was the highest in summer and lowest in winter. The evenness index was the highest in summer and lowest in spring. The richness index was highest in summer and lowest in winter. Furthermore, the dominance index was highest in spring and lowest in autumn.

• Ocean and Polar Research
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• v.34 no.4
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• pp.385-394
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• 2012

In this study, crude extracts of the marine eelgrass Zostera japonica and their solvent-partitioned fractions were evaluated for their inhibitory effect against AGS, HT-1080 and MCF-7 human cancer cells using MTT assay. Each of the crude extracts (acetone/methylene, chloride, and methanol) of Z. japonica showed a significant inhibitory effect on the growth of human cancer cells. The combined crude extracts were partitioned between $CH_2Cl_2$ and water. The organic layer was further partitioned between 85% aq. MeOH and n-hexane, and the aqueous layer was then fractionated into n-BuOH and $H_2O$, successively. Growth inhibition effects of solvent-partitioned fractions from Z. japonica on human cancer cells increased in a dose-dependent manner. Among these tested samples, the 85% aq. MeOH fraction revealed good inhibitory effects on the growth of AGS and HT-1080 human cancer cells, while the n-hexane fraction exhibited good inhibitory effects on the growth of AGS and MCF-7 human cancer cells. In addition, 85% aq. MeOH and n-hexane fractions enhanced mRNA expression of p53 gene. These results suggest that there is further scope for the isolation of active compounds from Z. japonica, which should show much stronger anticancer activity.