• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.1
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• pp.8-19
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• 2002

Spatial distribution pattern of macrozoobenthos was studied along the salinity gradient and sedimentary environment in the Watancheon estuary, Beobseongpo, southwest coast of Korea. Ten stations were set from the mouth towards the head of estuary. Three replicate sediment samples were taken using a van Veen grab (surface area $0.1m^{2}$) at each station between June 1998 and January 1999. A total of 114 species were collected during the study period and they are composed of 44 species of polychaetes (39%), 34 of crustaceans (30%), 24 of molluscs (21%) and 12 of miscellaneous. The former two taxa together accounted for 69% in the total number of species. The mean density was 3,053 ind./m$^{2}$, comprising 2,536 ind./m$^{2}$ from polychaetes (83%) and 439 ind./m$^{2}$, crustaceans (14%). Moreover, the mean biomass was 58.23 gwwt./m$^{2}$, consisting of 29.56 gwwt./m$^{2}$ from polychaetes (51%), 23.38 gwwt./m$^{2}$, molluscs (40%). A spionid polychaete Minuspio japonica, two corophiid amphipods Grandidierella japonica and Corophium sinense, a bivalve Potamocorbula amurensis were major dominants at the head of estuary where the salinity was relatively lower compared with contiguous sites. The distributions of M. japonica and G. japonica were significantly related to the salinity and sediment environment, respectively, whereas C. sinense and P, amurensis showed no significance. The nereid polychaete, Hediste japonica, also predominated at the head of the estuary where bottom salinity was relatively low. Species diversity was high at the mouth area whereas low diversity and few species number were seen at the stations in the head of the estuary, influenced by freshwater and sandy sediment. Based on the cluster analysis, the macrobenthic community was classified into four station groups from head (station group A) toward mouth (group D) in the study area. The number of species and abundance between station group B and C were significantly different. And the abundance of between two neighboring station groups (station group A and B, B and C, C and D) was also different. These results suggested that the spatial distribution pattern of macrobenthos in this estuary seemed mainly related to gradients in bottom salinity and sediment grain size among environmental factors.

• Journal of Plant Biology
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• v.16 no.3_4
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• pp.17-34
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• 1973

The physico-chemical factors, the distribution of chlorophyll and the primary production of the lakes Hwajinpo, Yongrangho, Chunchonho, Uiamho, Soyangho and Changjamot have been studied in order to make ecological comparison among these lakes during summer stagnation period of August to September of 1973. On the basis of the characteristics of these lakes, the lake types have been discussed. Thermocline is observed at 3-4m zone in the lake Changjamot and 4-5m zone in the lake Yongrangho. In the case of lake Hwajinpo and impoundments, the distinct thermal stratification is not observed at the summer stagnation period. As to vertical distribution of dissolved oxygen, a positive heterograde curve is obtained in the lakes Hwajinpo and Yongrangho. In the lake Changjamot the typical clinograde curve and the oxygen depletion in hypolimnion are observed. In the case of impoundments, however, the orthograde curve is observed in the lakes Chunchonho and Uiamho. While in the lake Soyangho, any stratification of the disssolved oxygen is not found. In the brackish lakes, such as lakes Hwajinpo and Yongragho, the salinity of hypolimnion is found to be much higher than that of epilimnion. In the lake Hwajinpo, the salinity of hypolimnion is exhibited 32.7$\textperthousand$, which is nearly the same as sea water. The distribution of nitrogenous compounds and phosphates is found to be high in the lake Changjmot. The silicate is also found in high concentration in the lake Chunchonho, and the distribution of nutrients in the brackish lakes is generally low. As to the vertical distribution of chlorophyll level, the lake Changjamot shows a stratum type and the brackish lakes L-type stratification. In the impoundments, lakes Chunchonho and Uiamho appear to be homogeneous type. Seasonal variation of chlorophyll level in the lake Changjamot is examined from January to September 1973. The vertical distribution of chlorophyll during the period of circulation from January to April is homogeneous type and is stratum type thereafter. The maximum chlorophyll level is 277.4mg/$m^2$ on June 23 and the pattern of seasonal variation of chlorophyll level is comparable to the type of eutrophy. The horizontal distribution of chlorophyll level is studied in the brackish lakes, Hwajinpo and Yongrangho. The pattern of distribution is found to be an irregular type. On the basis of measurements of primary production by means of the carbon-14 method and the distribution of chlorophyll level, it is concluded that the interior part of the lake Hwajinpo and Changjamot are eutrophic and the exterior part of the lake Hwajinpo, lake Yongrangho and the impoundments, lake Uiambo and Soyangho are mesotrophic.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.103-111
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• 2013

In this study, field measurements were conducted in the section about 7 km from sea dike to westward. The observations of along channel current were carried out, and water temperature and salinity were measured simultaneously at 10 stations during one tidal cycle, and sampling interval is 1 hour. The maximum ebb current is about 1.5 m/s at the surface layer but flood current is 0.4 m/s at the bottom layer during discharge period. Residual current during river discharge shows two layer structures which is typical characteristic of the estuary system. On the other hand, residual current during a period with no discharge has shown multi-layer structure different from general estuarine systems. The distribution of high salinity can be seen at the bottom layer as the effect of discharge does not reach down to the bottom layer during discharge. As a result, freshwater is not effected at the bottom layer during observation, and mixing of surface layer to bottom layer is reduced by stratification.

• Ocean and Polar Research
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• v.30 no.4
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• pp.379-399
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• 2008

Spatial-temporal variations in physiochemical water qualities (temperature, salinity, DO, SPM, POC and nutrients) of surface and bottom waters were investigated along the mid-western coastal area (Taean Peninsula to Gomso Bay) of Korea. Spatial distribution patterns of temperature and salinity were mostly controlled by the physical mixing process of freshwater from Geum River and/or Gyunggi Bay with nearby coastal water. A strong tidal front is formed off Taean Peninsula during spring and summer. Seasonal variations in nutrient concentrations, lower in spring and summer and higher in fall and winter, are primarily regulated by magnitude of phytoplankton occurrence rather than freshwater loadings into the bay. Based on seasonal and spatial variability of physicochemical parameters, water quality of the study area can be divided into four water masses; Gyunggi Bay-influenced Water Mass (GBWM), Geum River-influenced Water Mass (GRWM), Yellow Sea Bottom Cold Water Mass (YSBCWM) and Cheonsu Bay Water Mass (CBWM). Water quality of the GBWM (Taean Peninsula coastal area), which has relatively low salinity and high concentrations of nutrients, is strongly controlled by the Gyunggi Bay coastal water, which is under influence of the Han River freshwater. In this water mass, the mixed layer is always developed by strong tidal mixing. As a result, a tidal front is formed along the offshore boundary of the mixed layer. Such tidal fronts probably play an important role in the distribution of phytoplankton communities, SPM and nutrients. The GRWM, with low salinity and high nutrients, especially during the flood summer season, is closely related to physiochemical properties of the Geum River. During the flood season, nutrient-enriched Geum River water mass extends up to 60 km away from the river mouth, potentially causing serious environmental problems such as eutrophication and unusual and/or noxious algal blooms. Offshore (<$30{\sim}40m$ in water depth) of the study area, YSBCWM coupled with a strong thermocline can be identified in spring-summer periods, exhibiting abundant nutrients in association with low temperature and limited biological activity. During spring and summer, a tidal front is formed in a transition zone between the coastal water mass and bottom cold water mass in the Yellow Sea, resulting in intensified upwelling and thereby supplying abundant nutrients to the GBWM and GRWM. Such cold bottom water mass and tidal front formation seems to play an important role in controlling water quality and further regulating physical ecosystem processes along mid-western Korean coastal area.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.2
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• pp.57-65
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• 2003

Mapping of salinity distribution in the reclaimed lands was attempted by using the electromagnetic inductance technique. Field study was conducted to monitor ground conductivity with an electromagnetic inductance, EM 38 (Geonics), and electrical conductivity of the saturated extract, ECe of the soils, at the Daeho reclaimed land. EM values of horizontal mode, EMh, and vertical mode, EMv, mode were recorded at the interval of $2m{\times}2m$ from the ground. Soil samples were taken through the profile down to 100cm for calibration. ECe of poor drained area of Daeho, were in the range of $19.50-91.50ds\;m^{-1}$, while ECe of well-drained area ranged from $1.10-34.40ds\;m^{-1}$. Multiple regression equations for the measured EMv, EMh, and ECe were highly significant. The EMh showed higher correlation with ECe than EMv. With the multiple equation, ECgM could be calculated. Correlation between ECe and ECgM was the highest ($r=0.753^{***}$), when EMI readings were taken on the ground. The relationships were highly significant below 30 cm height of measurement, With the EM38 measurement, the salinity distribution was effectively expressed for the experimental filed in Daeho reclaimed land.

• Journal of Marine Life Science
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• v.1 no.1
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• pp.1-7
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• 2016

In order to assess seasonal and geographical characteristics of pollutant Escherichia coli, we investigated its distribution in Nakdong River mouth and Busan coastal water from February 2013 to November 2015. The coastal area was divided into five different zones (I-V) based on the pollutant level and geographical characteristics. During the study periods, water temperature and salinity varied from 7.50 to 27.64℃ and 16.82 to 34.82 psu, respectively. The annual water temperature variation was characterized in temperate zone. The salinity was significantly (p<0.05) decreased in zone IV and zone III after heavy rain during summer season in 2014, resulting led to elevated E. coli biomass. The highest colony formation of E. coli was recorded at 6,000 cfu l^-1 during autumn at station 1 (zone I). On the other hands, during all seasons of 2015, E. coli abundances were kept to be low level in zone III. The E. coli was not significantly (p>0.05) correlated with water temperature. However, the salinity was significantly (r=-0.53, p<0.05) correlated with the E. coli, implying that salinity plays a crucial role in the proliferation of E. coli. Consequently, E. coli in western Busan coastal water might have been significantly promoted by pollutant sources from Nakdong Rive discharge during the spring and summer rainy seasons depending on annual rainfall variations. On the other hands, E. coli in station 1 (i.e., Suyeong Bay) was obviously high due to influences of discharge water from municipal wastewater treatment plant. However, there was no clear seasonality of E. coli.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.115-121
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• 2009

In order to elucidate the mechanisms affecting plant distributions in the reclaimed dredging area in the Gwangyang steelworks, in the Gwangyang Bay, Korea, we examined soil characteristics and plant distributions in four study sites and a control site in the study area. Desalination occurring along a gradient with increasing elevation, resulting in decrease of soil pH, EC, P, K, Cl, Ca, Mg, and salt and an increase in soil T-N, silt, clay contents. From site 1 (the lowest-elevation site) to site 5 (the highest-elevation site), halophytes decreased in abundance and nonhalophytes increased. The dominant species in each site were: Phragmites communis, Limonium tetragonum, and 12 additional species at site 1, Carex pumila, Suaeda japonica, and 15 additional species at site 2, Spergularia marina, Scirpus planiculmis, and 22 additional species at site 3, Miscantus sinensis, Lespedeza bicolor, and 26 additional species at site 4 and Pinus thunberii, Rhododendron mucronulatum, and 39 additional species at site 5, which resembled a naturally-occurring P. thinbergii community. Cluster analysis of the vegetation data matrix grouped the 35 plots into 5 major groups, and cluster analysis using the soil environment data matrix revealed 4 major groups. CCA of the floristic and environmental data matrix showed a positive relationship of SAR, EC, Na, Cl, and Ca, which are related to salt, in the $1^{st}$ axis and $2^{nd}$ axis, but negative relationships for altitude, organic contents, silt, and clay contents. Notably, plant species in the reclaimed dredging area that were separated along the $1^{st}$ axis showed strong relationships with factors that related to salt. Long-term exposure to natural rainfall in the reclaimed dredging area changed the soil characteristics, such as salinity. This change in soil characteristics might alter the SAR, which affects plant survival strategies in a given habitat. These results strongly indicated that factors related to salt and elevation play important roles in determining the overall plant distribution in the reclaimed dredging area.

• Journal of Environmental Science International
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• v.14 no.11
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• pp.1063-1069
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• 2005

In order to investigate the distribution of suspended particulate matter of the surface water in the South Sea of Korea in early winter, the cruise results during 2 to 8 December 2004 were analyzed in relation to the hydrography. The front was formed along the line connecting between Tsushima and Cheju Islands, which divided the water into two water masses; the coastal water with for temperature and for salinity, and the Tsushima Warm Current Water with high temperature and high salinity. In the coastal water the suspended particulte matter was 5.0-6.5 mg/l, while in the oceanic water suspended particulate matter was 4.5-5.0 mg/l. The coastal water showed higher mixing effects, compared to the oceanic area where vertical stratification was clearly formed. These indicate that the distribution of suspended particulate matter was affected by the stratification or mixing of the water column. Also it is suggested that the mixing effects of sea surface cooling and rind play an important role on the distribution of suspended particulate matter in the South Sea of Korea in winter time.

• Proceedings of the KSRS Conference
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• v.1
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• pp.122-125
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• 2006

The distribution of phytoplankton pigments were studied bimonthly at four stations from the mouth of Mahanadi River at Paradip to the 36.7km off coast in Bay of Bengal during April 2001 to December 2002. Bottom depth was shallower than 40m in all stations. The pigment concentration of Chl-a was measured. It increased from surface to bottom in the water column. The water column integrated chlorophyll-a concentration (Chl-a) varied between 6.1 and $48.5mg{\cdot}m-^2$ with peaks during monsoon period (Aug & Oct). Spatial distribution of salinity depended strongly on freshwater runoff. The salinity was 5psu at river mouth and 25.15psu at offshore in monsoon period; however it was 30psu at the river mouth in summer. We found a linear relationship between the amount of river discharge and integrated Chl-a in coastal region from 2 years observations. Extending this result, we analyzed rainfall and coastal Chl-a using satellite data. The relationship between the river discharge and monthly accumulated rainfall estimated from TRMM and others data sources was analyzed in 2001 and 2002 using Giovanni infrastructure provided by NASA. The result depended on the specified area on TRMM images; the river delta area had sharper relationship than wider rain catchments area. Moreover, the relationship between monthly averaged Chl-a derived from SeaWiFS and monthly accumulated rainfall estimated from TRMM was analyzed from 1998 to 2005. It was clear that the broom in monsoon period was strongly controlled by rainfall on river delta.

• Spatial Information Research
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• v.14 no.2 s.37
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• pp.223-234
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• 2006

In order to examine spatio-temporal characteristics of coastal water quality, we applied GIS spatial analysis to the water quality data collected from observation points located on Korean coastal area during 1997$\sim$2004. The water quality parameters measured included: chlorophyll-a, pH, DO, COD, SS, dissolved inorganic nitrogen, dissolved inorganic phosphorous, salinity, temperature. The water quality data used in this paper was obtained only at selected sites even though they are potentially available at any location in a continuous surface. Thus, it is necessary to estimate the values at unsampled locations so as to analyze spatial distribution patterns of coastal water quality, Owing to this reason, we applied IDW(inverse distance weighted) interpolation method to water quality data and evaluated the usefulness of IDW method. After IDW interfolation method was applied, we divided the Korean coastal area into 46 sections and examined spatio-temporal patterns of each section using GIS visualization technique. As a result of evaluation, we can blow that IDW interpolation and GIS are useful for understanding spatial and temporal distribution characteristics of coastal water quality data which is collected from a wide area far many years.