• Journal of the Korean Society for Marine Environment & Energy
• /
• v.7 no.2
• /
• pp.89-97
• /
• 2004

Recently, Namak New Town is under construction adjacent to Mokpo City, and New Great Harbour Bridge between Mokpo City and Koha Island is designed to be built across Inner Harbour of Mokpo. Citizens' concerns about and participations in 「Campaign for Shaping Mokpo into Beautiful Seaport」 are required to make up the sight of Mokpo harbour beautifully. The of 「Master Plan for the Development of Beautiful Mokpo Seaport」 was reviewed. Citizens' levels of consciousness of and participation in 「Campaign for Shaping Mokpo into Beautiful Seaport」 were ascertained through questionnaire surveys of citizenry opinions, and prerequisites and requirements for the success of 「Master Plan for the Development of Beautiful Mokpo Seaport」 were suggested on the basis of the results of questionnaire surveys. As most of citizens are not satisfied with the existing urban environment in Mokpo City, the urban environment and the view of Mokpo are required to be made up according to the natural, social and environmental characteristics of Mokpo and its adjacent Islands in coastal waters. In order to cultivate citizens' basic cultural consciousness and sense of public kindness, cleanliness and orderliness, various educational programs are required to be developed and executed. Only when local government of Mokpo City collects the public opinions and continues to shape Mokpo into international beautiful seaport in the direction of a reflex of public opinion, Mokpo harbour can be made up into international beautiful seaport successfully with citizens' positive participation in citizenry practicable action plan.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.10
• /
• pp.6388-6398
• /
• 2014

To understand size fractioned chlorophyll a and material cycle characteristics in Jeju marine ranching area (JMRA), 4 times of survey were conducted from April to November 2008. Picoplankton on the surface in JMRA was on average, $0.30{\mu}g/L$(annual mean(M):17.3%) in the $0.03{\sim}0.84{\mu}g/L$ range, accounting for 17.3%. Nannoplankton and picoplankton was on average, $1.35{\mu}g/L$(M:78.0%) in the $0.22{\sim}3.93{\mu}g/L$ range, and $1.73{\mu}g/L$(M:4.7%) in the nd ~ 0.24 range, respectively. The 10m layer was similar to the surface. The measured values changed according to the measurement times but the nanoplankton composition ratio was higher throughout the year. In addition, the size fractioned chlorophyll a distribution in JMRA was similar to that of tropical sea area affected by the Monsoon rather than South Korean offshore coast geographically adjacent to the East China Sea and Japan coastal waters affected by the Kuroshio/Tsushima warm currents. That is, the material cycle of JMRA consists of a microbial food web rather than traditional food chain at a lower trophic levels. Primary production is deemed to have a higher possibility of being adjusted by top-down dynamics, such as micro-zooplankton grazing pressure rather than nutrients supply.

• Journal of Wetlands Research
• /
• v.8 no.3
• /
• pp.29-38
• /
• 2006

Digital Elevation Model (DEM) of intertidal flat can be widely used not only for scientific fields, coastal management, fisheries, ocean safety, military, but also for understanding natural and artificial topographic changes of the tidal flat. In this study, we generated DEM of the Ganghwado southern intertidal flat, the largest tidal flat in the west coast of the Korean Peninsula, using waterline method and interferometric synthetic aperture radar (InSAR). Constructed DEM which applied waterline method to the Landsat-5 TM and Landsat-7 ETM+ images closely expresses overall topographic relief of tidal flat. We found that the accuracy was determined by the number of waterlines which reflect various tidal conditions. The application of InSAR to the ERS-1/2 and ENVISAT images showed that only ERS-1/2 tandem pairs successfully generated DEM in the part of northern Yeongjongdo, but construction of DEM in the other areas was difficult due to the low coherence caused by a lot of surface remnant waters. In the near future, Kompsat-2 will provide satellite images having multi-spectral and high spatial resolution within a relatively short period at different sea levels. Application of waterline method to these images will help us construct a high precision tidal flat DEM. Also, we should develop DEM generation method using single-pass microwave satellite images.

• ALGAE
• /
• v.32 no.1
• /
• pp.57-66
• /
• 2017

The red alga Gracilaria vermiculophylla, a species native to the waters of Korea and Japan, has invaded marine coastal areas of Europe and the Americas, thriving in conditions that differ from those of its native habitat. In recent years, G. vermiculophylla has been discovered in the Long Island Sound (LIS) estuary growing alongside the native congener Gracilaria tikvahiae. The goal of this study was to determine whether the two strains of G. vermiculophylla from different regions of the world have evolved genetic differences (i.e., ecotypic differentiation) or if the physiological performance of the strains simply reflects phenotypic plasticity. Two strains of G. vermiculophylla (isolated in Korea and LIS) and a strain of the LIS native G. tikvahiae were grown for four weeks under temperatures ranging from 20 to $34^{\circ}C$ using a temperature gradient table (all other environmental conditions were kept constant). At the end of each week, wet weight of each sample was recorded, and thalli were reduced to the original stocking density of $1gL^{-1}$ (excess biomass was preserved for tissue carbon and nitrogen analysis). Generally, the growth rates of Korean G. vermiculophylla > LIS G. vermiculophylla > G. tikvahiae. After one week of growth G. tikvahiae grew 9.1, 12.0, 9.4, and 0.2% $d^{-1}$, at temperatures of 20, 24, 29, and $34^{\circ}C$, respectively, while G. vermiculophylla (LIS) grew 6.6, 6.2, 5.7, and 3.6% $d^{-1}$. G. vermiculophylla (Korea) grew 15.4, 22.9, 23.2, and 10.1% $d^{-1}$, much higher than the two strains currently inhabiting the LIS. On average, the LIS G. vermiculophylla strain contained 4-5% DW N, while the Korean strain and G. tikvahiae had more modest levels of 2-3% N DW. However, tissue N content declined as temperature increased in LIS and Korean G. vermiculophylla. The non-native haplotype may have evolved genetic differences resulting in lower growth capacity while concentrating significantly more nitrogen, giving the non-native a competitive advantage.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.8 no.2
• /
• pp.59-69
• /
• 2003

As part of study on the microbial food web in the southern Jeju Island of Korea, Planktonic tintinnids and aloricate oligotrichs were investigated from July 1998 to June 2000 to understand seasonal variation and water mass indication with environmental factors. 39 species of tintinnids were identified representing 1 order, 11 families, 20 genera. Tintinnid abundance ranged from 100 to 5,400 cells.1$^{-1}$ (mean 314 cells.1$^{-1}$ ), and oceanic species were mainly dominant in fall and winter season, while neritic species were a little pre- dominant in spring and summer season. 15 species of aloricate oligotrichs were identified representing 1 order, 5 families, 7 genera, and many belonged to genus Strombidium which was most abundant and most frequently occurred in many months. Abundance of aloricate oligotrichs ranged from 140 to 21,000 cells.1$^{-1}$ (mean 2,356 cells.1$^{-1}$ ). Species diversity and standing crops of tintinnids were quite different according to seasons, but few seasonal variations were detected in aloricate oligotrichs. In terms of water mass indication tintinnids represented obvious characteristics which were affected by marine environmental factors, but alor- icate oligotrichs had no such apparent indication as tintinnids. Ciliates were more abundant and more diverse in inshore than in offshore station. Total carbon biomass of ciliates ranged from 0.01 to 136.06 $\mu\textrm{g}$C.1$^{-1}$ (mean 5.01 $\mu\textrm{g}$C.1$^{-1}$ ). The carbon biomass, however, did not coincided with seasonal variations of abun- dance Vertical profiles of mean abundance of both tintinnids and aloricate oligotrichs were similar, and had same trend as those of mean chlorophyll o concentration. It suggests that phytoplankton and ciliates reflected the prey-predator relationship in the study area.

• Korean Journal of Remote Sensing
• /
• v.16 no.3
• /
• pp.243-260
• /
• 2000

Ocean remote sensing reflectance of just above water level was modeled using inherent optical properties of seawater contents, total absorption (a) and backscattering(bb) coefficients ($R_{rs}$=0.046 $b_b$/(a+$b_b$). This modeling was based on the specific absorption and backscattering coefficients of 5 optically active seawater components； phytoplankton pigments, non-chlorophyllous suspended particles, dissolved organic matters, heterotrophic microorganisms, and the other unknown particle components. Simulated remote sensing reflectance($R_{rs}$) and water leaving radiance(Lw) spectra were well agreed with in-situ measurements obtained using a bi-directional fields remote spectrometer in coastal waters and open ocean. $R_{rs}$ values in SeaWiFS bands from the model were analyzed to develop 2-band ratio ocean color chlorophyll with those observed insitu. Also, chlorophyll algorithm based on remote reflectance developed in this study fell in those obtained by a SeaBAM working group. The model algorithms were examined and compared with those observed insitu. Also, chlorophyll algorithm based on remote reflectance developed in this study fell in those obtained by a SeaBAM working group. The remote reflectance model will be very helpful to understand the variation of water leaving radiances caused by the various components in the seawater, and to develop new ocean color algorithm for CASE-II water using neural network method or other analytical method, and in the model of fine atmospheric signal correction.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.7
• /
• pp.902-908
• /
• 2017

To determine the horizontal and temporal distribution of firefly squid, Watasenia scintillans (W. scintillans), larvae, we conducted surveys using IKMT (mesh size: $500{\mu}m$) and CTD (SBE9plus) with Fisheries Research Vessel (FRV, TAMGU 21) in the southern part of the East Sea in summer (August) and autumn (September and November) 2015. A total of 238 larvae, ranging in mantle length (ML) from 0.6 mm to 18.5 mm, were collected at 28 stations. Abundance and larval distribution density were significantly higher in summer than in autumn during the study period. Especially, the highest density of W. scintillans was observed in the coastal waters of the East Sea from Pohang to Pyunghae where cold water masses were distributed in summer. Optimum embryo survival temperature ($6-16^{\circ}C$) 40 to 180 m depth ranges for stations which larvae were collected.

• ALGAE
• /
• v.34 no.3
• /
• pp.237-251
• /
• 2019

The dinoflagellate genus Alexandrium is known to often form harmful algal blooms causing human illness and large-scale mortality of marine organisms. Therefore, the population dynamics of Alexandrium species are of primary concern to scientists and aquaculture farmers. The growth rate of the Alexandrium species is the most important parameter in prediction models and nutrient conditions are critical parameters affecting the growth of phototrophic species. In Korean coastal waters, Alexandrium affine and Alexandrium fraterculus, of similar sizes, often form red-tide patches together. Thus, to understand bloom dynamics of A. affine and A. fraterculus, growth rates and nitrate uptake of each species as a function of nitrate ($NO_3$) concentration at $100{\mu}mol\;photons\;m^{-2}s^{-1}$ under 14-h light : 10-h dark and continuous light conditions were determined using a nutrient repletion method. With increasing $NO_3$ concentration, growth rates and $NO_3$ uptake of A. affine or A. fraterculus increased, but became saturated. Under light : dark conditions, the maximum growth rates of A. affine and A. fraterculus were 0.45 and $0.42d^{-1}$, respectively. However, under continuous light conditions, the maximum growth rate of A. affine slightly increased to $0.46d^{-1}$, but that of A. fraterculus largely decreased. Furthermore, the maximum nitrate uptake of A. affine and A. fraterculus under light : dark conditions were 12.9 and $30.1pM\;cell^{-1}d^{-1}$, respectively. The maximum nitrate uptake of A. affine under continuous light conditions was $16.4pM\;cell^{-1}d^{-1}$. Thus, A. affine and A. fraterculus have similar maximum growth rates at the given $NO_3$ concentration ranges, but they have different maximum nitrate uptake rates. A. affine may have a higher conversion rate of $NO_3$ to body nitrogen than A. fraterculus. Moreover, a longer exposure time to the light may confer an advantage to A. affine over A. fraterculus.

• Korean Journal of Ichthyology
• /
• v.33 no.3
• /
• pp.184-190
• /
• 2021

Since the original description of new species, Eumicrotremus jindoensis, we confirmed the first occurrence of E. jindoensis based on a single specimen (22.3 mm SL) caught by inshore stow net at the coastal waters of Boryeong of Korea. However, our specimen slightly differed from type specimens in having more vertebrae (26 vs. 21~24), longer snout (17.4% vs. 8.1~9.1%), longer preanus length (67.5% vs. 58.0~58.3%) and shorter second dorsal fin base (15.3% vs. 20.2~20.8%). Comparing with mtDNA COI and Cytb sequences, we could not find any differences in mtDNA Cytb sequences between our specimen and type specimens, which suggest that those morphological differences may belong to local variation by habitat and environmental condition between off Jindo Island and off Boryeong in Korea. Eumicrotremus uenoi is known from the southern sea of Korea narrowly (Busan, Tongyeong, and Jeju Island), the other congeneric species (E. asperrimus, E. pacificus, and E. taranetzi) from only the eastern sea of Korea, but E. jindoensis from the central coast to southern coast of western Korea.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.1
• /
• pp.29-37
• /
• 2021

In the event of a marine pollution accident, Korea, which is bordered by the sea on three sides, would suffer tremendous damage. According to an analysis of marine pollution accidents in Korea, most pollutants were small fishing boats and tugboats. In particular, urgent safety measures are required due to the high incidence of marine pollution accidents caused by stranded tugboats. This study aims to decrease secondary marine pollution accidents by preparing measures to prevent accidents by stranded tugboats, the main source of pollution accidents. To this end an experiment was conducted to mark 63 locations where stranded accidents have occurred on the GPS plotters of 61 tugboats operating in Boryeong sea area. Its effectiveness was then investigated. The result showed that there was no stranded accident by the subject ship during the 20-month experiment period. As a result of survey of the captains, 36 out of 40 respondents (90%) stated that the experiment was significantly helpful in ensuring safe navigation, thus confirming its effectiveness. Various measures were proposed to prevent stranded accidents, including providing information to manufacturers and users by marking the location of grounded accidents on GPS plotters and posting the location information of unknown reefs on the official website of institution Korea Hydrographic and Oceanographic Agency.