• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.43-50
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• 2000

The obseuations on the seasonal fluctuations of phytoplankton community in Haechang Bay of the Korean southern sea were carried out during four seasons from 1997 to 1998. A total of 77 species of phytoplankton including 10 freshwater species, belonging to 51 Benera was identified. Seasonal succession of dominant species was evident in Haechang Bay; Chaetoceros cunisetus, Skeletonema costatum, Eurampia zodiacus, Dictyocha fibula and Ceratium furca in summer, C. curisetus in autunm, C. cunisetus Rhizosoienia setigera and E. zodiacus in winter and S. costatum in spring. The phytoplankton community in Haechang Bay showed various species composition and was occupied with centric diatoms all the year round, Densities of the phytoplankton cell number by the samples of Haechang Bay ranged from $8.4{\times}10^3\;cells/l\;to\;2.0{\times}10^5\;cells/l$ with the mean value of $9.2{\times}10^4\;cells/l$ in summer, from $3.2{\times}10^3\;cells/l\;to\;4.6{\times}10^6\;cells/l$ with mean of $6,2{\times}10^4\;cells/l$ in autumn, from $8.4{\times}10^3\;cells/l\;to\;4.3{\times}10^4\;cells/l$ with mean $2.2{\times}10^4\;cells/l$ in winter and from $1.0{\times}\;10^3\;cells/l to\;4.6{\times}10^4\;cells/l$, with mean of $1.1{\times}10^4\;cells/l$ in spring. Phytoplankton standing crops fluctuated with an annual mean of $4.7{\times}10^4 cells/l$ between the lowest value of $1.0{\times}10^3\;cells/l$ in spring and the highest value of $4.6{\times}10^5 cells/l$ in autumn, That is, phytoplankton standing crops was high in summer and autumn, while it was very low in winter and spring.

• The Korean Journal of Ecology
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• v.24 no.5
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• pp.297-301
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• 2001

The objectives of this study were to evaluate the extent of heavy metals(As, Pb, Cd, Hg)accumulated in sediments of the Kwangyang Bay, and to investigate bioaccumulation of heavy metals(As, Pb, Cd, Hg) in shellfish(Ruditapes philippinarum) commonly found in the intertidal zone of the Kwangyang Bay. The data was also compared with that of Namhae and Kohung intertidal zones, which were regarded as control stations in this study. Substantial geographical variations in heavy metal concentrations in the sediment samples were found. However, heavy metal concentrations in the sediment collected from the intertidal zones of Yochon(stations I, J) and Myodo(stations G, H) close to Yochon Industrial Area exhibited relatively higher heavy metal concentrations, compared to those from other intertidal zones(stations A, B, C) adjacent to POSCO at Kwangyang Bay. In addition, stations A, B, C showed lower heavy metal concentrations in the sediments than controls(K, L). The annual mean concentrations of the heavy metals in the shellfish from the stations(G, H, I, J) were significantly higher than those from other stations(A, B, C, D, E, F). Nevertheless, heavy metal accumulation in sediments was not reflected in bioaccumulation of heavy metals in shellfish, probably indicating that interactions between the heavy metals in sediment and shellfish might be poor in the current study area, Kwangyang Bay.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.753-763
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• 2022

In coastal and inland bays, where most of Korea's aquaculture is located, massive aquaculture damage occurs every year due to frequent anomalous high water temperatures. The interannual fluctuations of water temperature in July over the past four years (2018-2021) were the second largest since 1990 (after the period of 1994-1997) due to anomalous high temperatures, rainy seasons, and typhoons. Through analysis of heat flux and heat balance in areas of concern for high water temperatures (i.e., Cheonsu Bay, Gamak Bay, Guryongpo), the occurrence of high water temperatures in Cheonsu Bay and Gamak Bay in the summer seasons was confirmed to derive mainly from heat inflow through the sea surface from the air. Based on estimations of the average ocean heat transport rate in July for the four-year period of 2018-2021, Cheonsu Bay and Gamak Bay accounted for 13.5% and 62.3% outflow of the net heat flux, respectively. However, the ocean heat transport rate in Guryongpo Hajeong differed significantly from -174.5% to 132.5% of the net heat flux by year depending on the occurrence of cold water mass.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.462-472
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• 2023

We investigated the physio-chemical and geochemical parameters in the spraying shellfish aquacultures (Yeoja and Gangjin Bay) to establish the systematic strategy for effective environmental management. Spatial variation of each parameter showed partially significant difference (P<0.05) between Yeoja and Ganjin Bay, inferring the discriminative progress (i.e., accumulation and degradation) of the autochthonous organic matter within the aquaculture environments. We additionally integrated various properties (e.g., water/sediment quality, natural hazard, and biological health) which may affect the biological growth within the aquaculture habitats based on the biogeochemical cycles related to environmental components and aquaculture species. We used a screening approach (i.e., one out-all out; OOAO) which can permit the assessment of the health levels of aquaculture species, the scoring for other parameters (seawater, sediment, and natural hazard) as three levels (excellent, moderate and poor) depending on the complex interactive properties occurring in the aquaculture environments. Actual, discriminative scores obtained via our case studies may confirm that these stepwise processes are effectively evaluated for optimal health conditions within the aquaculture habitats. Thus, this approach may provide valuable insights for effective environmental management and sustainable growth of aquaculture operation.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.153-153
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• 2021

Storm Storm event is one of major issues in South Korea due to devastating damage at its landfall. A series of statistical study on the historical typhoon records consistently insist that the typhoon translation speed (TS) is on slowdown trend annually, and thus provides an urgent topic in assessing the extreme storm surge under future climate change. Even though TS has been regarded as a principal contributor in storm surge dynamics, only a few studies have considered its impact on the storm surge. The landfall angle (LA), another key physical factor of storm surge also needs to be further investigated along with TS. This study aims to elucidate the interaction mechanism among TS, LA, coastal geometry, and storm surge synthetically by performing a series of simulations on the idealized geometries using Delft3D FM. In the simulation, various typhoons are set up according to different combinations of TS and LA, while their trajectories are assumed to be straight with the constant wind speed and the central pressure. Then, typhoons are subjected to make landfall over a set of idealized geometries that have different depth profiles and layouts (i.e., open coasts or bays). The simulation results show that: (i) For the open coasts, the maximum surge height (MSH) increases with increasing TS. (ii) For the constant bed level, a typhoon normal to the coastline resulted in peak MSH due to the lowest effect of the coastal wave. (iii) For the continental shelf with different widths, the slow-moving typhoon will generate the peak MSH around a small LA as the shelf width becomes narrow. (iv) For the bay, MSH enlarges with the ratio of L/E (the length of main-bay axis /gate size) dropping, while the greatest MSH is at L/E=1. These findings suggest that a fast-moving typhoon perpendicular to the coastline over a broad continental shelf will likely generate the extreme storm surge hazard in the future, as well as the slow-moving typhoon will make an acute landfall over a narrow continental shelf.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.329-338
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• 2009

Using physiological data which had been already published, we investigated variation of phytoplankton communities due to changes of marine environmental factor at 2 stations of northern Gamak Bay from November 2007 to September 2008. Dominant species (occupied species above 10%) were dinoflagellates 1 species and diatom 11 species. Diatom Skeletonema costatum was observed as dominant species during the periods except in summer (i.e. July and August), especially, which occupied above 90% in December. On the other hand, dominant species during summer were diatom Eucampia zodiacus and Chaetoceros spp., Considering the results of other physiological studies, S. costatum might be non-dominant species during summer by following reasons 1) growth rate of E. zodiacus might be taster than that of S. costatum under the temperature during summer although both S. costatum and E. zodiacus are eurythermal and euryhaline species. 2) Species as E. zodiacus characterized by low affinity with light might have a chance to be dominant with increasing optical transparency due to low suspended solids in July. 3) In aspect of nutrition, species of growth strategist as S. costatum could be dominant in relatively low concentration of phosphate and species of storage strategist as E. zodiacus could be dominant in relatively high concentration of phosphate during summer in this study area. In order to understand the phytoplankton dynamics in detail, the physiological informations about strains isolated from this study area are necessary because physiological conditions are different depending on isolated area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.520-525
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• 2023

This study aimed to detect Enterococcus spp. strain, a fecal contamination indicator, by PCR assay from short neck clams Venerupis philippinarum in Cheonsu Bay area, Chu Island area and Wonsan Island area, the west coast of Korea, from November 2022 to February 2023 of Enterococcus spp. strain was detected in 19 (79.2%) among 24 samples, and its concentration ranged from <18 to 33,000 MPN (most probable number)/100 g. The 269 isolated Enterococcus spp. strains were identified by PCR assay, and Enterococcus spp. distribution in short neck clams were E. faecium (39.8%), E. faecalis (23.0%), E. hirae (21.9%), E. gallinarum (10.4%), E. casseliflavus (1.5%), E. durans (1.5%) and unidentified strains (1.9%). Thus, E. faecium was the most dominant strain followed by E. faecalis. Overall, these results provide novel insight into the necessity for shellfish sanitation in the sea and could help reduce the fecal contamination risk.

• Asia pacific journal of information systems
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• v.32 no.4
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• pp.890-915
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• 2022

Although existing studies on e-health have usually focused on e-health services adoption intention, there is a dearth of studies on the barriers that affect e-health services retention intention especially in India. Additionally, although studies have mostly focused on utilizing expectation-confirmation model to understand innovation related barriers, innovation resistance theory (IRT) has been overlooked. As Indian e-health service providers face stiff challenges due to customer's unwillingness to continue using the service, there is a need to bridge the research gap that exists in this context. This mixed-method study, based on responses received from 289 participants and 1154 online negative reviews from e-Health providers in India, examines the barriers from the IRT stance. Results of this study reveal a notable negative association between tradition, value and financial barrier and intention to continue using e-health services. Additionally, continuance intention affects recommendation. The study concludes with various implications and scope for future research.

• Structural Engineering and Mechanics
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• v.21 no.4
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• pp.469-494
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• 2005

In order to consider the modified seismic response of framed structures in the presence of masonry infills, proper models have to be formulated. Because of the complexity of the problem, a careful definition of an equivalent diagonal pin-jointed strut, able to represent the horizontal force-interstorey displacement cyclic law of the actual infill, may be a solution. In this connection the present paper, continuing a previous work in which a generalised criterion for the determination of the ideal cross-section of the equivalent strut was formulated, analizes some models known in literature for the prediction of the lateral cyclic behaviour discussing their field of validity. As a support of the discussion, the results of an experimental investigation involving single story-single bay infilled reinforced concrete. Frames under vertical and lateral loads with different kind of infill (actually not yet so much investigated) are presented. Finally, an improvement of a model known in the literature is proposed, taking the results of the experimental tests before mentioned into account.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.908-926
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• 2014

This study investigated the community structure and health assessment of macrobenthic assemblages in Wonmun Bay, in the southern coast of Korea. The total number of species and mean density were 170 species and $1,269\;indivuduals/m^2$, respectively. The major dominant species were the bivalve Theora fragilis ($230{\pm}446\;indivuduals/m^2$) and the polychaetes Lumbrineris longifolia ($180{\pm}339\;indivuduals/m^2$), Sigambra tentaculata ($124{\pm}153\;indivuduals/m^2$), Paraprionospio patiens ($104{\pm}293\;indivuduals/m^2$) and Capitella capitata ($82{\pm}223\;indivuduals/m^2$). Community statistics [cluster analysis and nonmetric multidimentional scaling (NMDS) ordination] revealed that the macrobenthic community structure in the study area was classified into three station groups for both seasons. Several biotic indices based on macrobenthic communities have been developed to assess the ecological quality of coastal ecosystems. In this study, the ecological status was assessed by four biotic indices Shannon's H', the AZTI Marine Biotic Index (AMBI), multivariate-AMBI (M-AMBI) and the Ecological Conservation Index (ECI). The ecological statuses of the macrobenthic communities in Wonmun Bay were poorer in the summer than in the spring. The results of the present study indicate that three biotic indices ( i.e.; Shannon's H', M-AMBI and ECI ) were better correlated with bottom dissolved oxygen than the AMBI in Wonmun Bay.