The primary production at 10 stations around the coast line of Cheju Island has been investigated from the viewpoint of standing crops(cells/e), chlorophyll-a concentration and CO₂ fixation of phytoplankton during the period from June, 1987 to March, 1989. Phytoplankton standing crops ranged from 2,025 to133,734 cells/ethrough the year, increasing from June and showing a peak in August. The distribution of standing crops was the highest in the eastern area and the lowest in the northern area. Chlorophyll-a concentration ranged from 0.45 to 2.59 ㎎/㎥ during the study period, which was much lower than that in the other Korean coastal waters. To estimate the CO₂ fixation of phytoplankton, daily primary production (㎎C/㎥/day) has been determined using C-14 method. It ranged 1.31-7.15, 34.54117.04, 22.283.64, 8.53-11.95㎎㎎/㎥/㎥/day in winter, summer, fall, and spring, respectively, and showed the highest in the western area. The carbon assimilation number(㎎C/㎎ chl-a/hr)was also higher in summer than in other seasons. The general characteristics of primary production of phytoplankton around the coast line of Cheju Island was high in the eastern and western regions during the summer season.

한국 제주도와 대마도 주변해역을 중심으로 고등어와 정어리를 주어획대상으로 선단조업을 하고 있는 건착망어업의 어선의 성능, 어패의 크기, 어획성능, 조업해역별 단위노력당 어획량등을 조업어선의 톤급별로 분석, 검토한 결과는 다음과 같다. 1. 망선의 총톤수(x)와 건착망의 면적(y)간에는 y=538.8x+99657.3의 관계가 있었다. 2. CPUE의 계절변동지수는 11~4월은 기분보다 높고, 5~10월은 낮은 현상을 나타내었다. 3. 각 해역에 있어서 톤급별 어획성능지수는 톤급별, 해역별 CPUE는 1%의 유음수준에서 차가 인정되었다. 4. 톤급별 망어패의 효율은 A와 D급선 보다 B와 C급선이 높은 현상을 나타내었다

In order to know sea water characteristics around coast line of Cheju Island, physical and chemical environmental factor analyses have been performed with data observed from June 1987 to April 188. Water temperature was over 10℃ even in winter with highest value of 14.7℃ in the southern part over the whole study area. Concentrations of DO, COD and SS were as low as those in the standard sea-water-quality classes [I] and [II]. Nutrient concentration was higher in the present study region than on the coastal areas by previous works, suggesting influx of materials from land. The ratio of N/P ranged from 21.6 to 67.4 (mean : 38.8). Concentration of Chlorophgll-a was high in eastern and southern part throughout the year, except a special high value of 3.89㎎/㎥ at Gosan, western part of the study area, in August.

The characteristics of the anomaly level, variability and distribution of monthly mean precipitation have been investigated at 4 different weather stations on Cheju Island, Korea. The results of this study are as follows : 1) The SE area of Cheju Island turns out to be the heavy rain area from February to July than the NW area of the island. The heavy rain area migrates from the SE area to the NE area during the period from August to January. 2) The rainy season, in which monthly mean precipitation is more than 180mm, appears in Cheju City and Sungsan from June to August, in Seoguipo from April to August, and in Daejung from June to July. On the other hand, the dry season, in which monthly mean precipitation is less than 100㎜, appears in Cheju City from October to May, in Sungsan from December to February in Seoguipo from October to February, and in Daejung from October to March. 3) The variability of precipitation on Cheju Island appears high during the 'Changma' spell and it is also high in autumn, particularly in October, and appears low in March and April. 4) The frequency of the anomaly level shows maximum not only on the normal level but the lower normal level and the upper normal level in monthly precipitation. The annual frequency distribution of each anomaly level shows maximum on the normal level, and the frequency of the lower normal level is a lot higher than the lower normal level. 5) The precipitation of the summer season acts as an important variable in deciding between the dry year and the moisture year. In particular, this applies to the large precipition of June in the moisture year and the small precipitation of July and August in the dry year.

A model experiment of purse seine by the circulating water tank was carried out on the changes of net shape and the tension of purseline under operation in two layer current. In the circular tank, the two layer current was made by cutting off the current of upper layer and producing the bottom current by the equipment shown in Fig. 1. The model experiment of purse sein was made on a reduced scale 1 :400, and the experiment was carried out according to the Tauti's model law. When the bottom current of O. 5 knot flows to lower part of three-eighths of net, following results are derived. The depth of sinkerline reached only about 80% of that of no current set. The horizontal shift of sinker line caused by the bottom current is maximized in tight set. The enclosed area by the floatIine immediately after the completion of set net is 61. 5% in tight set, 50. 0 % in loose set and 54. 1 % in lateral set of those in the case of no current. In the first half period of pursing, the tension of the purseline is enhenced by the bottom current and the pattern of increasing is irregular in the tension curves.

In order to investigate the performance for the mackerel purse seine of one boat purse seiner using in the sea area of Cheju Island, a model net is made of the scale of 1/400 of its full scale, and model test on the shape of net and the tension of purse line is carried out in the stagnant water channel of the circulating water tank. Designing and testing for the model net are based on the Tauti's law. The obtained results are as follows; 1. The sinking rate of net is maximized the value of 6.40 m/min from 5 to 10 minutes after shooting net, and the mean value is 6.13 m/min. 2. The enclosed area formed with the float line after pursing operation is 76-84% of the area which is formed immediately after the shooting operation. At that time, purse seine is pulled inward the circle of surrounding net about 26.5% of the diameter. 3. In operating, when longitudinal section area of the central part of the net is maximized, the split area of both the wing-ends is 31-32% of the former. 4. When the time for the completing of pursing is 20 minutes, the maximum tension of the purse line is about 10.2 tons.

조립질 퇴적물의 근원지에 관한 정보를 제공할 뿐만 아니라 유용 광물자원으로서의 가치를 지 니는 황해남동니질대와 제주남서니질대 표층퇴적물 내 중광물의 특성을 비교 연구하였다. 두 지역에 서 각각 28개씩 시료를 선정하여 중광물을 분리한 후 실체현미경과 주사전자현미경 관찰, 에너지 분 산형 분광분석과 전자현미분석을 실시하였다. 각섬석과 녹염석은 연구지역에서 주된 중광물로서 두 광물의 합계 함량이 70% 이상을 점유한다. 저어콘과 스핀은 황해남동니질대에서, 인회석과 금홍석은 제주남서니질대에서 상대적으로 많은 함량을 나타내며, 모나자이트는 황해남동니질대 일부 지역에서 만 산출된다. 스핀과 모나자이트 함량은 황해남동니질대 북부에서 남부로 갈수록 감소하는 경향을 보 여준다. 황해남동니질대는 낮은 석류석-저어콘 지수와 금홍석-저어콘 지수를 가지는데 반하여, 제주남 서니질대는 높은 석류석-저어콘 지수와 금홍석-저어콘 지수를 가진다. 각섬석의 경우 황해남동니질대 는 대부분 보통각섬석에 해당되지만, 제주남서니질대는 파가사이트, 처마카이트, 보통각섬석, 투각섬 석 등 다양한 조성을 가진다. 황해남동니질대 지역의 석류석은 높은 Mg와 낮은 Ca 함량을, 제주남서 니질대 지역 석류석은 낮은 Mg와 다양한 Ca 함량을 가진다. 이와 같이 두 지역의 중광물 특성이 서 로 다른 것은 두 지역의 퇴적물 기원지가 다르다는 것을 지시한다. 황해남동니질대의 퇴적물 기원지 는 인접한 한반도의 서해안으로 유입되는 하천 퇴적물인 것으로 여겨지나, 추후 황해로 유입되는 강 퇴적물과 해양 퇴적물에 대한 추가적인 중광물 연구가 진행되어야만 정확한 기원지와 퇴적과정에 대 한 해석을 할 수 있을 것으로 판단된다.

제주 남서 이질대에서 채취된 138개의 해양표층퇴적물 시료와 황하와 양쯔강 하천퇴적물 시료에 대하여 반정량 X선회절분석법에 의한 점토광물 상대조성을 바탕으로 주성분분석을 이용하여 퇴적물의 기원지를 연구하였다. 제1주성분과 제2주성분이 전체 자료의 90% 이상을 설명하기 때문에 두 주성분만을 가지고 R프로그램을 이용하여 주성분분석을 실시하였다. 제주 남서 이질대 내 각각의 점토광물의 분포양상은 매우 복잡하지만, 전체적인 분포양상을 고려할 때, 스멕타이트와 카올리나이트는 서부지역에서 높은 함량을 보였고 일라이트와 녹니석은 동부지역에서 상대적으로 높은 값을 나타냈다. 제주 남서 이질대의 동부지역에서 보여주는 상대적으로 높은 일라이트와 녹니석 함량은 양쯔강 퇴적물과, 서부지역에서의 높은 스멕타이트와 카올리나이트 함량은 황하 퇴적물과 더 유사한 양상을 나타낸다. 이러한 통계 처리 결과를 바탕으로 제주 남서 이질대의 동부지역은 양쯔강에서 유래하였고 서부지역은 황하로부터 기원했음을 추정할 수 있다. 추후 퇴적물 기원지 연구에 주성분분석이 유용하게 활용될 것으로 기대한다.

Butyltin compounds (BTs) in seawater, sediments and organisms (Thais clavigera, Liolophura japonica and Cellana nigrolineata), were quantitatively determined to evaluate their distribution inside Songsan Harbor of Cheju Island. In addition, imposex in T. clavigera was used to assess the effect on organisms of BTs. Analysis of the samples collected in seawater, sediments (March, June and August) and organisms (May, July and August) in 1998, confirmed the contamination of BTs in the aquatic environment inside Songsan Harbor. The main BTs species in seawater and sediments was monobutyltin (MBT), tributyltin (TBT), respectively, irrespective of survey time. In organisms, TBT and dibutyltin (DBT) were detected in similar concentrations for T. clavigera and L. japonica, but for C. nigrolineata, DBT concentration was the highest. TBT, the most toxic to aquatic organisms among BTs, was found at concentrations which were sufficient to have a serious effect on the sensitive organisms upon chronic exposure. The relatively high correlations (r>0.83) between BTs indicated that DBT and MBT were mainly degraded from TBT based on antifouling paint and their sources were negligible. The sedimentary organic matters did not have influence on the distribution of BTs in marine environment, and lipid content in T. clavigera did not show a correlation with TBT concentrations. The rate of occurrence of imposex in T. clavigera was 100 %, and the relative penis length index (RPLI) and the relative penis size index (RPSI) which represent the degree of imposex were 79.7%, 58.1%, respectively. Measurement of imposex in T. clavigera was expected to be a very helpful tool for preliminary survey of BTs prior to trace analysis of BTs.

The purpose of this study is to investigate the physicochemical characteristics of salinization of groundwater at the estern area of Cheju island. For this purpose, the major ions of groundwater. spring water are analyzed. The concentration of Cl- and Na-+K- contained in the groundwater at near the coastline are higher than those at inland area away from the coastline. The water quality components of groundwater observed at this area can be classified into 4 types such as Na-Cl, HCO3, Na-Cl-HCO3 and Ca-HCO3. The concentration ratio of SO4- to Cl- is 0.1354(R2=0.972) at this area. This value is very similar with Dittomer's ratio of 0.13. For Na-, K-, and Mg2+ versus Cl-, their ratios also show a significant relationship between sea water and groundwater in this area. From the chloride-bicarbonate ratio, it can be estimated that the intrusion distance of seawater from coastline to inland area is 2.8km at Onpyung-Nansan, Sangdo and Pyungdae areas, and 5.4㎞ at Kosung-Susan area. The mixing ratio between seawater and fresh water by the intrusion of seawater is decreased with the distance toward inland from coastline. This ratio(fresh water : seawater) is 80:20 in spring water adjacent the coastlines, Onpyung area and 99.8:0.2 in the well at No.3 of Susan located at inland away from the coastline. The concentration of Na- observed at field is 25∼45% lower than that theoretically calculated by this mixing ratio. Based on the data of EC, the equipotential line of 500μmhos/㎝ is located at 4∼5㎞ point at Kosung-Susan area and 2.5㎞ point at the other area. The equation of correlation between Cl- concentration and EC values is Cl-=0.1927EC-16.683 for the area lower than 500μmhos/㎝ and Cl-=0.2773EC for the area beyond 500 μmhos/㎝.

The purpose of this paper is to present the environment change of Cheju Island as land development process using GSIS(Geo-Spatial Information System) technique. We implemented the process based on the maps of soil color, underground water pollution points, land use, land development planning and land sight seeing supported by Cheju Province Office. To use the maps for GSIS data, first we transformed the picture data of the office into raster structured picture data using scanner. Second, the coordinate system was added to raster data using 1/50000 geographic map. Third, we estimated land planning process using GSIS technique(overlay and reclass technique). The results showed that land development effected the natural environment(forest, green field, farm land). However, the chemical pollution and land sight seeing was not so much effected by the land development that was found.

To study the residue of organophosphorus pesticides in the ocean environment on the Cheju island, EPN[O-ethyl-O-4-nitrophenyl phenylphosphonothioate] and monocrotophos [Dimethyl-1-methyl-2-methy] carbamoylvinylphosphate] of organophosphorus pesticides are surveyed on coastal environment of Cheju city and Wimi in May and October 1996. The qualified limit detection of EPN and monocrotophos are 0.005ng/mL and 0.006ng/mL., in the water by GC-FPD, respectively. The qualified limit detection of EPN and monocrotophos are 0.010ng/g and 0.012ng/g in the solid such as sediment and sea organism by GC-FPD, respectively. EPN and monocrotophos are not detected in seawater and sediment. Moreover EPN and monocrotophos are neither detected in seaweed cava (Ecklonia cava), Agar (Gelidium amansii), turban sell(Batillus cornutus) and sea urchin(Anthocidaris Crassispina). EPN, monocrotophos used in the farm on the Cheju island are not residued in the coastal environment in the Cheju island.

The adsorption and leaching of organophosphorus pesticides (phenthoate, diazinon, methidathion) were investigated in Namwon soil(black volcanic soil), Aewol soil(very dark brown volcanic soil) and Mureung soil(dark brown nonvolcanic soil) sampled in Cheju Island. The Freundlich constant, K value, was 52.4, 31.3 and 27.7 for phenthoate, diazinon and methidathion in Namwon soil, respectively and decreased in the order of phenthoate, diazinon and methidathion among the pesticides. The K value of phenthoate was 52.4, 15.9 and 5.9 for Namwon, Aewol and Mureung soil, respectively and was the highest for Namwon soil with very high organic matter content and cation exchange capacity(CEC). The Freundlich constant, 1/n, showed a high correlation with organic matter content, i.e., its value was less than unity for organic matter rich soil(Namwon soil) and greater than unity for organic matter poor soil(Mureung soil). Total recoveries of pesticides in soil and leachate with leaching in soil column, were in the range of about 74∼86%. The leaching of pesticides was less for phenthate with high K values, and more for methidathion with low K values among the pesticides. It was slower for Namwon soil with high K values, and faster for Mureung soil with low K values among the soils.

In order to manage the water quality from the flowing streams in Cheju Island, the characteristics of water quality was investigated from August, 1996 to May, 1997 and the pollutant loadings for future were estimated from the watershed at each stream. Comparing the mean concentrations of each water quality with the criterion of water quality in river, it was under I class except for Changgo Stream, for DO, under I class at the whole station for SS and under Ⅱ class for BOD. As the pollutant loadings at each stream in 2020 is compared with those in 1996, the estimated results are as follows : 1) for BOD, 59% at Donghong Stream, 24% at Yeonoe Stream, 44% at Ohngpo Stream and 57% at Changgo Stream. 2) for T-N, 91% at Donghong Stream, 76% at Yeonoe Stream, 63% at Ohngpo Stream and 89% at Changgo Stream. 3) for T-P, 69% at Donghong Stream, 42% at Yeonoe Stream, 45% at Ohngpo Stream and 73% at Changgo Stream The point source loadings discharged through combined sewer could be treated at sewage treatment plant. However, the expected slow decreasing rate of BOD, T-N, and T-P loadings is due to the part of untreated nonpoint source loadings. Nonpoint source loading overflow typically occurs when the flow of stormwater combined with sewage exceeds the capacity of the interceptor sewers. Since most of the sewers used in Cheju Island are the combined sewers, the combined overflow sewage is bypassed into the receiving water area after a rainstorm. Therefore, a means to control nonpoint source loadings should be considered for the river and marine water quality management.

Soybean [Glycine max (L.) Merr.), mungbean [Vigna radiata (L.) Wilcz.], cowpea [V. unguiculata (L.) Walp.], adzuki bean [V. angularis (Willd.) Ohwi & Ohashi], maize [Zea mays L.], sorghum [Sorghum bicolor (L.) Moench], sorghum ~times sudangrass [So bicolor intraspecific hybrid], and Japanese millet [Echinochloa crusgalli var. frumentacea (Link) W.F. Wight] were grown at two planting dates (18 June and 15 July) at Cheju in 1997 to select the best forage legumes adapted to Cheju Island for grass-legume forage rotation. Averaged across planting dates and cultivars, dry matter (DM), crude protein (CP), and total digestible nutrient (TDN) yields were 5,646, 1,056, and 3,637 kg/ha for soybean, 4,458, 676, and 2,661 kg/ha for mungbean, 3,289, 553, and 2,055 kg/ha for cowpea, 3,931, 674, and 2,489 kg/ha for adzuki bean, 12,695, 969, and 7,642 kg/ha for maize, 17,071, 1,260, and 8,857 kg/ha for sorghum, 16,355, 1,163, and 8,543 kg/ha for sorghum ~times sudangrass hybrid, and 8,288, 929, and 4,091 kg/ha for Japanese millet. Soybean was higher in CP, ether extract (EE), and TON content but was lower in nitrogen free extract content compared with the three other legumes. The legumes had much higher CP (13.7 to 21.9%), EE (2.42 to 6.23%), and TDN (58.7 to 69.9%) content but lower in crude fiber (CF) content (17.3 to 25.3%) than did the grasses tested except maize which had relatively lower CF content but higher TDN content. These results suggest that soybean could be the best forage legume for grass-legume forage rotation in the Cheju region.

Two determinate soybean cultivars, 'Baegunkong' and 'Namhaekong', were planted on 8 Jone, 23 June, and 8 July 1996 at Cheju at planting densities of 33, 43, 53, 63 plants per m2 to determine the optimum planting density of double crop soybean for recently recommended cultivars in Cheju area at various planting dates. The plant height, and the diameter and node number of main stems decreased as planting was delayed. The plant height increased but the stem diameter and node number decreased with increasing planting density. Pod number per plant was greater for Namhaekong than for Baegunkong and was not affected by planting date. Pod number per plant decreased but pod numbers per ~textrmm2 increased with increasing planting density. The number of seeds per pod was greater at the two later plantings and fewer at the highest planting density. 100-seed weight decreased with delaying planting. The seed weight was lighter at the highest planting density for Baegunkong but there was no difference for Namhaekong among the planting densities. The seed yield of Baegunkong was greater for 23 June and 8 July plantings (2,280 and 2,420 kg/ha) than for 8 June planting (1,450 kg/ha) while that of Namhaekong was greatest at 23 June planting (2,690 kg/ha) compared with 8 June and 8 July plantings (1,890 and 2,080 kg/ha). Across the planting dates and cultivars, seed yield increased from 1,860 to 2,290kg/ha as the planting density increased from 33 to 53 plants/~textrmm2 and then leveled off with a further increase in planting density.

Based on the X-ray powder diffraction (XRD) and M ssbauer spectroscopy, the thermal behavior and phase transformations of two clays are investigated for raw and fired conditions, which are collected from Kwangryeongli and Ildo district in Cheju Island. M ssbauer spectra at room temperature and 20for two clays show that paramagnetic Fe3- is the structural iron of the layer silicate and ferrihydrite, and superparamagnetic goethite has about 50% of total iron contents. The XRD peaks of hematite for the fired clays appear from 800℃ in Kwangryeongli clay and from 600℃ in Ildo district clay, respectively. The structural Fe2+ was completely oxidized into Fe3- at 400℃ for Kwangryeongli clay and 500℃~600℃ for Ildo district clay, respectively. The structural Fe2+ was completely oxidized into Fe3- at 400℃. For the temperature ranging from 400℃ to 700℃~800℃, two fired clays exhibit the dehydroxylation of the clay mineral. A disintegration of the clay mineral structure is observed from 700℃~800℃ to 1100℃, followed by the onset and spread of vitrification process. It is also shown that well-crystallized hematite phase is formed at the temperature higher than 1100℃ and the relative absorption area decreases, which might be related to the recrystallization of alluminosilicate matrix.

The characteristics of spring machanism in the Cheju Island were analyzed by statistical techniques. Basic characteristics, areal and altitudinal variations, and correlations of spring data were ivestigated. In this study, however, the subjects of the study are the 451 springs, the whole basin of Cheju Island devided into four groups. In this study, analyzed the spring phenomena on the basis of both the geologic elements and the topographic elements. Also, the spring zone in Cheju Island are classified into three types that the mountain area, the middle area, the coastal area in spring distribution by altitude. The quentity of spring and variability show subvariety on the average according to Meinzer`s classification and the whole basin of spring shows various distributions from Third to Sixth. The results of this study can be utilized to evaluate the condition of groundwater development in Cheju Island.

In order to investigate the adsorption characteristics of organochlorine pesticides chlorothalonil and dicofol with soil colors and regions for soils of an orange orchard, the soils were sampled at 3 regions, respectively, among black volcanic, dark brown volcanic, and brown nonvolcanic soils. Every soil has a higher clay proportion (49-75%) in soil texture and the organic carbon content and cation exchange capacity with soil decreased in the following sequence: Black volcanic > Dark brown volcanic > Brown nonvolcanic soils. Especially those in black volcanic soils were much higher than others. The retention time, quantitative detection limit, and extractian, efficiencies of chlorothalonil and dicofol were 2.82min, 1.5ng/mL, 93.6% and 3.64min, 4.5ng/mL, 94.2%, repectively. The Freundlich constant, Kd, was higher in dicofol compared to chlorothalonil and in the black volcanic soils that have higher organic carbon content and cation exchange capacity. The Freundlich constant, 1/n, was in the range of 0.76-0.89 in the black volcanic soils that have a higher organic matter(16.4-19.8%), whereas it was in the range of 1.02-1.13 in the brown nonvolcanic soils that have a lower organic matter(2.4-3.4%), and so it was considered that 1/n was dependent on the organic matter.