• Journal of the Korean Society of Marine Environment & Safety
• /
• v.14 no.2
• /
• pp.111-117
• /
• 2008

We estirmted the yearly and monthly variation in discharge from the Nakdong River Barrage. We studied the total monthly discharge, the mean daily discharge, and the maximum daily discharge based on the observational discharge data for the 11-year period 1996-2006. We also examined the correlation between the discharge and the meteorologiml factors that influence the river inflow. The results from this study are as follows. (1) The total monthly discharge for 11 years at the Nakdong River Barrage was $224,576.8{\times}10^6\;m^3$: The daily maximum was in 2003, with $56,292.3{\times}10^6\;m^3$. The largest daily mean release discharges occurred in August with $52,634.2{\times}10^6\;m^3$ (23.4% of the year), followed by July and September in that order with 23.1 and 17%, respectively. (2) The monthly pattern of discharge could be divided into the flood season for the period July-September (discharge =$1000{\times}10^6\;m^3$/day), the normal season from April to June and October (discharge=$300{\times}10^6\;m^3$/day), and the drought season from December to March (discharge < $300{\times}10^6\;m^3$/day). (3) Periods of high temperature, low evaporation loss, and short sunshine duration produced a much higher discharge in general. Conditions of low rainfall and high evaporation loss, as was the rose in 2003, tended to reduce the discharge, but high rainfall and low evaporation loss tended to increase the discharge as it did in 200l. (4) The dominant wind directions during periods of high discharge were NNE (15.5%), SW and SSW (13.1%), S(12.1%), and NE (10.8%) This results show that it run bring on accumulation of fresh water when northern winds are dominant, and it run flow out fresh water toward offslwre when southern winds are dominant.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.7
• /
• pp.821-828
• /
• 2016

The water quality and phytoplankton presence in the ballast water (BW) of 37 vessels originating from the international ports of China were investigated to facilitate negotiations for exemptions to the Ballast Water Management Convention (BWM Convention). The shortest duration given BW spent in a vessel was $3.91{\pm}4.61days$ in area "A", which included the Bohai Sea. Total suspended solids, dissolved organic carbon, and particulate organic carbon ranged from 1.80 to $266mg\;L^{-1}$, from 1.09 to $5.79mg\;L^{-1}$, and from 0.17 to $3.65mg\;L^{-1}$, respectively. A low average concentration of nutrients was measured in BW from area "C", but the concentration of nutrients in BW from area "B" (around the Changjiang estuary) was high, which may be related to the relevant supply of freshwater. A high chlorophyll-a concentration (> $1{\mu}g\;L^{-1}$) was measured in six vessels, three of which carried BW in the area "A". High abundance of phytoplankton (> $10,000cells\;L^{-1}$) was measured in four vessels, two of which carried BW in the area "C". Vessel No. 37, originating from Hong Kong Bay in area "C", showed a high density of dinoflagellates. The results suggest that BWM Convention exemption negotiations with China should be performed cautiously.

• Journal of Plant Biology
• /
• v.15 no.s
• /
• pp.1-32
• /
• 1972

In order to utilize for the prevention and preservation of the Han River from the environmental pollution the present studies were carried out to clarify the microflora and estimation of the water pollution levels of the Han River. In addition to the above regional and seasonal fluctuation of the phytoplankton was also examined. Samples of phytoplankton were collected from 6 stations in the South Han River during the period from December, 1971 to October, 1972. The results obtained during the present studies are as follows: 1. The phytoplankton samples collected from 6 stations, Yeoju, Hajapo-ri, Yangpyeong, Daruraegi, Giduwon and Paldang were identified and classified by Engler's classification system(1954). It resulted in 2 phylum, 2 classes, 7 orders, 10 families, 29 genera, 137 species, 1 sub-species, 49 varieties, 6 forma and 2 variety-forma. The total numbers of phytoplankton identified were 195 species, of which 7 families, 27 species, 26 varieties, 4 forma and 2 variety-forma are new to Korea, that of 54 species are first described in Korea. 2. In lower area of the Han River it is found 53 species from Paldang and in middle area it is found 114 species from Giduwon, 95 species from Daruraegi, 66 species from Yangpyeong, 71 species from Hajapori and 81 species from Yeoju. In standpoint of seasonal fluctuation of phytoplankton, the total numbers of the plankton is more abundant in summer than in winter season and it shows bimodal pattern. 3. As compared with previous data which obtained from 30 stations covering estuary to upper area, both South and North Han River, during the period from 1965-1972 it is shown that 10 species of the South Han River and 11 species of the North Han River are found throughout all seasons. Among the above species two are common in both area. In the other hand it is found that 9 species in spring season and 6 species in fall season in the South Han River and 10 species in spring, 23 species in summer, 4 species in fall and 15 species in winter season in the North Han River shows their seasonal fluctuation in this area. Among the seasonal occurrence of phytoplankton 10 species were consider to be indicator for the estimation of biological water pollution levels. 4. According to Fjerdingstad's water pollution level system (1963) the total numbers of 1, 230 species which have been collected from the Han River since 1965 includes 27 species of phytoplankton as indicator; 3 species of blue-green algae, 20 species of diatom, and 4 species of green-algae. 5. With 27 indicator species new estimation of water pollution level system was arranged for water pollution in the Han River. 6. The lower part of the central area of the Han River indicates mesosaprobic. In central area of the Han River shows mesosaprobic and oligosaprobic, but predominant in mesosaporobic. And it is indicated that mesosaprobic, oligosaprobic, and polysaprobic factors mixed up in the North Han River. Compare with their water pollution level in the South and North Han River, with author's new system, it is estimated that North Han River is more polluted than South Han River. 7. The reason why North Han River is more polluted suggested that the selfpurification action was limited by their circulation speed. The rapid speed of water in the North Han River is mainly caused by their topography and water-drainage from waterpower plant. In conclusion the central area of the Han River consist of mesosaprobe zone, as a part with oligosaprobe zone. But the presence of polysaprobe zone in the North Han River gives us many problems in future for the nationa development programme and natural conservation in this area.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.6
• /
• pp.720-728
• /
• 2001

Cercaria yamagutii Ito, 1957 (C. yamagutii) was found in Lunatia fortuni (L. fortuni) and Neverita didyma (N. didyma) collected from the tideland of Sim-po located at the estuary of the Mankyong River, Chonbuk. It was finally confirmed that the parasite is Acanthoparyphium tyosenense Yamaguti, 1939 (A. tyosenense) and its life history was clarified in this study. Mactra veneriformis (M. veneriformis) was artificially infected with C. yamagutii isolated from L. fortuni and N. didyma. It began to intrude into M. veneriformis through the inhalent canal. Five hours after infection, the tails of the cercaria began to be separated from the main body and the cercaria started to form cysts. Mature cysts were formed 340 hours (14 days) after infection. The cysts were $300\sim360{\mu}m$ in diameter and the encysted metacercarias were $790\sim800\times300\sim310{\mu}m$ in size. The metacercarias were administered orally to Larus crassiostris (L. crassiostris), and adult worms of $84.5\sim112.5\times55\sim65{\mu}m$ were found full of eggs with $2.20\~3.70$ mm long and $0.40\~0.59$ mm wide after 10 days. In a field study, it was observed that the infection rate of A. tyosenense is $99.5\%$ in M. venerifomis, $76.3\%$ Solen strictus (S. strictus), and $37\%$ Ruditapes philippinarum (R. philippinarum), No difference was found among different host sizes, It was concluded that the first intermediate hosts of A. tyosenense Yamaguti were L. fortuni, N. didyma, Tympanotonus microptera, Cerithidea (Cerithidea) largillierti, Cerithidea (Cerideopsilloa) cingulata, the second intermediate hosts M. venerifomis, S. strictus and R. philippinamn, and the final hosts L. crassiostris and Melanitta fusca stejnegeri.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.6
• /
• pp.691-696
• /
• 2001

The first bloom of Cochlodinium polykrikoides was observed in the estuary of Nak-dong river near Pusan in Korea in 1982. Since then, there have been irregular blooms, sometimes spread over the adjoining .to Jinhae Bay even though it was confined to the bay and its vicinites until 1988. It had been outbroken frequently in the adjacent to Tongyeong, Geoje, Namhae and Yeosu coast since 1989. It became widespread along the coast of the South Sea to the East Sea of Korea in 1995. And in October in 1998 and 1999, the bloom had been taken place in Kunsan coast of Yellow Sea. According to the observations in situ, the frequency of occurrence has been increased year by year. The prevailing bloom season was from July to October with peak in September. The duration of the bloom became longer with the year, and sometimes lasted more than one month. The density of the bloom did not exceed 5,000 cells $mL^{-1}$until 1991, but it increased year by year to the highest of 43,000 cells $mL^{-1}$ in 1999. With respect to the assembleges of species in dinoflagellate blooms, C. polykrikoides was one of the important species with diatoms and the other dinoflagellates in 1980s. But since then, C. polykrikoides made an almost monospecific bloom. Based on two decadal observations of C. polykrikoides blooms, it became widespread throughout whole coast of the Korea, persistent for about one or two month long in some year, and monospecisc high density blooms. It was reported that significant fish mortalities were caused by this harmful dinoflagellate blooms especially in the fishfarms accomodating intensive fish cages such as Tongyeong, Namhae-do, Geoje, Yeosu and Geomun-do fishfarming yards. This widespread and persistent harmful algal blooms impede the development of marine aquaculture industries.

• Korean Journal of Agricultural Science
• /
• v.26 no.2
• /
• pp.77-93
• /
• 1999

This study is aiming at identifying the foreward and backward lingkage effects of the farm land base development project. Korean Government has continuously carried out farmland base development projets including the integrated agricultural development projects. large and medium scale irrigation projects and the comprehensive development of the four big river basin including tidal land reclamation and estuary dam construction for the all weather farming since 1962. the starting year of the five year economic development plans. Consequently the irrigation rate of paddy fields in Korea reached to 75% in 1998 and to escalate the irrigation rate, the Government had procured heavy investment fund from IBRD. IMF and OECF etc. To cope with the agricultural problems like trade liberalization in accordance with WTO policy, the government has tried to solve such problems as new farmland base development policy, preservation of the farmland and expansion of farmland to meet self-sufficiency of foods in the future. Especially, farmland base development projects have been challanged to environmental and ecological problems in evaluating economic benefits and costs where the value of non-market goods have not been included in those. Up to data, in evaluating benefits and costs of the projects, farmland base development projects have been confined to direct incremental value of farm products and it's related costs. Therefore the projects'efficiency as a decision making criteria has shown the low level of economic efficiencies. In estimating economic efficiencies including Leontiefs input-output analysis of the projects could not be founded in Korea at present. Accordingly this study is aimed at achieving and identifying the following objectives. (1) To identify the problems related to the financial supports of the Government in implementing the proposed projects. (2) To estimated backward and foreward linkage effects of the proposed project from the view point of national economy as a whole. To achieve the objectives, Hwangrak benefited area with reservoir which is located in Seosan-haemi Disticts, Chungnam Province were selected as a case study. The main results of the study are summarized as follows : a. The present value of investment and O & M cost were amounted to 3,510million won and the present value of the value added in related industries was estimated at 5.913million won for the period of economic life of 70 years. b. The total discounted value of farm products in the concerned industries derived by the project was estimated at 10,495million won and the foreward and backward linkage effects of the project were amounted to 6,760 and 5,126million won respectively. c. The total number of employment opportunities derived from the related industries for the period of project life were 3,136 man/year. d. Farmland base development projects were showed that the backward linkage effects estimated by index of the sensitivity dispersion were larger than the forward linkage effect estimated by index of the power of dispersion. On the other hand, the forward linkage effect of rice production value during project life was larger than the backward linkage effect e. The rate of creation of new job opportunity by means of implementing civil engineering works were shown high in itself rather than any other fields. and the linkage effects of production of the project investment were mainly derived from the metal and non-metal fields. f. According to the industrial linkage effect analysis, farmland base development projects were identified economically feasible from the view point of national economy as a whole even though the economic efficiencies of the project was outstandingly decreased owing to delaying construction period and increasing project costs.

• The Journal of Engineering Geology
• /
• v.14 no.1
• /
• pp.1-20
• /
• 2004

This study focuses on the hydrochemical characteristics in goundwater affected by reclamation at 2000 Sydney Olympic Games site, Sydney, Australia. The Olympic Games site can be divided into three areas, i.e. reclaimed areas; landfill areas and non-infilled areas. In the current work, 'reclaimed areas' were previously estuarine, and were filled with waste materials and are now above present high tide level, whereas 'landfill areas' are areas where deposition of waste materials occurred above sea level. No deposition of waste took place in 'non-infilled areas'. This study was also evaluated by three different types such as deep boreholes, shallow boreholes and standpipes. The hydrochemishy of groundwaters in reclaimed and non-in-filled areas is characterized by Mg- and Ca-enrichment, whereas groundwaters in landfill areas are elevated in K and NO₃. Na, K and Mg are the dominant cations in groundwater from reclaimed areas and Na and K are the dominant cations in groundwater in landfill areas. Na and Mg are the dominant cations in groundwater in deep boreholes, whereas Na and K are the dominant cations in groundwater in shallow boreholes and standpipes. There is no distinct trend in heavy metals with electrical conductivity in the groundwater between the re-claimed, landfill and non-infilled areas. Fe and Mn in landfill areas with respect to reclaimed areas and non-infilled areas show a distinct increase in concentration with declining pH. Mean electrical conductivity values in the deep and shallow boreholes are higher than that of standpipes, but the minimum and maximum value of electrical conductivity in groundwater in standpipes shows remarkably different value, probably due to perched pond. There is no correlation between Cu, Pb, Zn, Cr concentrations in groundwater with pH, from deep boreholes, shallow boreholes and standpipes, except for Fe and Mn, which demonstrate increasing concentrations with declining pH. The results revealed a close association between elevated concentrations in groundwater and the presence of fill materials at the site. Trace metals teachability from re-claimed soils adjacent to estuary plays a significant role in determining their potential environmental risk to surrounding environment.

• Korean Journal of Environmental Biology
• /
• v.35 no.4
• /
• pp.549-556
• /
• 2017

Rivers continuously transport terrestrial organic carbon matter to the estuary and the ocean, and they play a critical role in productivity and biodiversity in the marine ecosystem as well as the global carbon cycle. The amount of terrestrial organic carbon transporting from the rivers to ocean is an essential piece of information, not only for the marine ecosystem management but also the carbon budget within catchment. However, this phenomenon is still not well understood. Most large rivers in Korea have a well-established national monitoring system of the river flow and the TOC (Total Organic Carbon) concentration from the mountain to the river mouth, which are fundamental for estimating the amount of the TOC flux. We estimated the flux of the total terrestrial organic carbon of five large rivers which flow out to the Yellow Sea, using the data of the national monitoring system (the monthly mean TOC concentration and the monthly runoff of river flow). We quantified the annual TOC flux of the five rivers, showing their results in the following order: the Han River ($18.0{\times}10^9gC\;yr^{-1}$)>>Geum River ($5.9{\times}10^9gC\;yr^{-1}$)>Yeongsan River ($2.6{\times}10^9gC\;yr^{-1}$)>Sumjin River ($2.0{\times}10^9gC\;yr^{-1}$)>>Tamjin River ($0.2{\times}10^9gC\;yr^{-1}$). The amount of the Han River, which is the highest in the Korean rivers, corresponds to be 4% of the annual total TOC flux of in the Yellow River, and moreover, to be 0.6% of Yangtze River.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.5
• /
• pp.680-687
• /
• 1999

To understand the role of shelf sediment in phosphorus biogeochemical cycle, we carried out sequential sediment extraction (SEDEX) of P and porewater analysis on 14 core samples collected in the South Sea of Korea, SEDEX classified P-pools into 5 phases and results are grouped into two categories: reactive P (loosely sorbed-P and Fe bound-P) and refractory P (detrital inorganic-p, authigenic mineral-P and organic-P). Total P concentrations are decreased with sediment depth in all samples as a result of dissolution to porewater. Reactive P comprises about $20\~50\%$ of total P, and iron bound-P is the major form consisting $70\~80\%$ of reactive P-pool. Iron bound-P decreases sharply with depth. Depth profiles of dissolved P concentration in porewater show mirror image of iron bound-P, revealing the role of FeOOH as a regulator of reactive P supply to overlying water column. Authigenic mineral-P consists less than $5\%$ of total P, thus removal of reactive P by converting into refractory P seems inefficient in shelf sediment. This implies that continental shelf sediment sequesters P temporarily rather than permanently. Results show local variation. Nakdong estuary receiving large amount of terrigenous input shows the highest concentration of total P and reactive P. Here iron oxyhydroxides at the surface sediment control the water column flux of P from sediment. Although total P content at the surface is comparable (500$\~$600 ${\mu}g{\cdot}g^{-1}$) between the South Sea and East China Sea, the former contains more iron bound-P and less derital inorganic-P than the latter. Reasons for the difference seem due in part to particle texture, and to biological productivity which depends roughly on the distance from land.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.24 no.3
• /
• pp.483-494
• /
• 2019

From the cosmopolitan superiority of the as the first world map completed in 1402 with surprisingly detailed images and contents on the Africa Continent it is reasonable to think that the Koreans in early fifteen century were already with highly up-to-date perspectives on the universe and world history and cultures. However, some 490 year later the first phytohydrographic plankton investigation in the neritic seas of Korea was performed by a Japanese company with sampling points covering from Tokyo Bay through Jeju neritic waters to Shanghai estuary, which was in turn preceded by the first oceanographic investigation other than the simple mapping Koreans seas by using two French sailboats. The first phytohydrographic plankton investigation in Korean seas were behind the world first oceanic plankton exploration, the German Plankton Expedition, by 25 years. Starting from the oceanographic investigation including phytohydrographic samplings in the whole Yellow Sea in 1915 the full-scale phytohydrographic plankton studies were tried in Korean seas which is well represented by the 1921 oceanographic investigation on the whole East Sea with 80 sampling stations. In 1932 two separate oceanographic investigations followed, one in the East Sea where 78 stations from Busan to southern Sakhalin Island were simultaneously visited by 50 research vessels for the physical, chemical, and biological oceanographic studies, and the other one in southern coast and western East Sea of Korea where ocean current observation as well as plankton sampling were made in 120 stations to understand the relationship between the ocean current and plankton distribution in the region. In 1933-1934 more intensified investigations on phytohydrography were carried out particularly in the East Sea as an integral part of the basic marine ecosystem studies for the Myeong-Tae (Alaska Pollock) resources estimation. Scientists' attitude for the marine investigation and research activities seemed to be almost unchanging even to the year 1943, which could be reflected by the fact that publication of the results from the investigations performed in 1945 were finally done in 1967 at Tokyo. Some 70 years later from the mid-twenty century we might be standing on the turning-point of "need to be prepared" for the new era of changing paradigm by reviewing, archiving, and analyzing the prior information big data from the previous ocean observation and biohydrographic investigations. At the same time each professional societies for the above mentioned sciences might trigger a continuous project to reorganize and update the records on related bibliography and its history every 30 years.