• Title/Summary/Keyword: dominant period

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Community Structure of Macrobenthos in the Subtidal Soft Bottom in Semi- enclosed Youngsan River Estuarine Bay, Southwest Coast of Korea (반폐쇄적인 영산강 하구역 조하대 연성저질의 저서동물 군집)

  • LIM Hyun-Sig;PARK Kyung-Yang
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.3
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    • pp.320-332
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    • 1999
  • Investigations were made on the community structure of macrobenthos in the subtidal soft bottom around semi-enclosed Youngsan River estuarine bay, southwest coast of Korea during the period from April 1995 to February 1996. Three macrobenthos samples were collected at 40 stations using a van Veen grab(0.1 m^2) during the study period. A total of 206 species of macrobenthos was identified. Their mean density and biomass (wet-weight, wwt) were $1,137 ind./m^2$ and $65.28 gwwt/m^2$, respectively. Of these, there were 74 species of polychaetes ($36\%$), 60 molluscs ($39\%$), 51 crustaceans ($25\%$) and 21 miscellaneous taxa. Molluscs were represented as a density- and biomass-dominant faunal group with a mean density of $601 ind./m^2$($53\%$ of the total benthic animals) and biomass of $25.37 gwwt/m^2$($39\%$ of total biomass): It was followed by polychaetes with $405 ind./m^2$($40\%$ of the total density). Total number of species and diversity were Bow in the inner estuarine bay containing high mud content and organic matter, whereas they were high in the outer stations containing low mud content and organic matter. Major dominant species were one biralve, Theora fragilis and three Polychaetes, Tharyx sp., Poeciloceatus johnonni and Lumbrineris lontifolia whose mean densities were $490ind./m^2$, $96ind./m^2$, $74ind./m^2$and $52 ind./m^2$, respectively. Cluster analysis indicated that the study area could be divided into four station groups: two innermost station groups, a central bay and an outer station group. The species diversity increased from the inner station group toward the outer groups. These results were discussed in terms of both the environmental factors and distribution of benthic community.

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fisheries Biology of Shrimps in the South Western Waters of Korea -1. Species Composition of Catches and Spawning Season of Acetes sp. for the Korean Shrimp Fishery- (우리나라 서해남부해역의 새우류 어획물에 대한 자원생물학적 연구 -1. 어획물조성과 젓새우류의 산란시기-)

  • Oh Chul Woong;Jeong In Ju
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.35 no.3
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    • pp.223-230
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    • 2002
  • Investigations were made on catch composition, sex ratio, relationships between carapace length, body weight and fecundity and spawning season of major target shrimps (Acetes chinensis, A. japonicus) in the shrimp fishing areas of south-western coastal waters, accounting for about $45\%$ of annual shrimp landings in Korea. Catches were collected monthly in the fishing areas from March 2000 to February 2001, using single pocket-walled fishing gear, Total 59 species (shrimps 14, fishes 34, other crustaceans 8 and cephalopods 3 species) occurred. During the study period the bycatch-to-shrimp ratio of shrimp fishery was 2.42 in April 2000 and less than 1 for all months except for August 2000 and Febuary 2001. Compared with shrimp fishery of other areas and nations, these results indicate that effect of the fishing gear on catches of other species is minor, suggesting higher gear selectivity for shrimps. Of shrimps, there were two dominant species (A. chinensis, A. japonirus). Average sex ratio was 1.44 $\pm$ 0.42 for A. japonicus and 1,44 $\pm$ 0.43 for A. chinensis, which are dominant females in August. Average fecundity was 4,812 $\pm$ 1,511 for A. japonicus and 5,561 $\pm$ 1,900 for A. chinensis. In the two species mature females were found in the period from May to August. Similarly, the gonadosomatic index (GSI) was higher in July and August, with a peak in July, These results indicate that their main spawning season was summer.

Eco-friendly remediation and reuse for coastal dredged materials using a bioaugmentation technology (생물증강법을 이용한 오염해양준설토의 환경친화적 정화 및 재활용)

  • Kim, In-Soo;Ha, Shin-Young;Koh, Sung-Cheol
    • Korean Journal of Microbiology
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    • v.51 no.4
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    • pp.374-381
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    • 2015
  • Occurrences of coastal dredged materials are ever increasing due to port construction, navigational course maintenance and dredging of polluted coastal sediments. Ocean dumping of the coastal dredged materials has become virtually prohibited as London Treaty will be enacted as of the year 2012. It will be necessary to treat and recycle the dredged materials that may carry organic pollutants and heavy metals in a reasonable and effective process: collection of the dredged materials, liquid and solid separation, and treatment of organic compounds and heavy metals. In this study we have developed a continuous bioreactor system that can treat a mixture of silt and particulate organic matter using a microbial consortium (BM-S-1). The steady-state operation conditions were: pH (7.4-7.5), temperature ($16^{\circ}C$), DO (7.5-7.9), and salt concentration (3.4-3.7%). The treatment efficiencies of SCOD, T-N and T-P of the mixture were 95-96%, 92-99%, and 79-97%. The system was also effective in removal of heavy metals such as Zn, Ni, and Cr. Levels of MLSS during three months operation period were 11,000-19,000 mg/L. Interestingly, there was little sludge generated during this period of operation. The augmented microbial consortium seemed to be quite active in the removal of the organic component (30%) present in the dredged material in association with indigenous bacteria. The dominant phyla in the treatment processes were Proteobacteria and Bacteroidetes while dominant genii were Marinobacterium, Flaviramulus, Formosa, Alteromonadaceae_uc, Flavobacteriaceae_uc. These results will contribute to a development of a successful bioremediation technology for various coastal and river sediments with a high content of organic matter, inorganic nutrients and heavy metals, leading to a successful reuse of the polluted dredged sediments.

A Baseline Survey on Development of Primary Health Care in the Rural Korea -Sanpuk Village, Kumsa-Myun, Yuju- Gun, Kyunggi-Do- (농촌지역의 일차보건사업 개발을 위한 기초조사 연구 - 경기도 여주군 금사면 산북부락을 중심으로 -)

  • Kim, Myung-Ho;Yun, Suk-Woo;Rhee, Hae-Soak
    • Journal of agricultural medicine and community health
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    • v.12 no.1
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    • pp.5-27
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    • 1987
  • It is widely recognized that primary health care in the community is one of the most important and effective health measures in these days. However, it is reality that unsatisfactory health care system, ineffective utilization of health care by the community people in the rural area are hampering better understanding for primary health care. Therefore promoting health for the rural people and increasing understanding about primary health care, the baseline survey in the community focused in examination for safe community water supply was carried out. The survey was conducted through August 25-31, 1986 in order to find out health problems and relevant factors and to define the demographic characteristics of $^*$Sanpuk village, Kumsa-Myun, Yuju-Gun, Kyunggi-Do, Korea. Household survey was carried out for every home by trained interviewers. The major results are found out as follows : 1) 84.2%(400 houses) of total households were surveyed because 15.8%(75 houses) were unable to survey due to either refusal against interview or absence of family. These 400 households were composed of 1,697 residents(male:830, female 867). Educational level of respondents showed 34.1% as elementary school graduated. Religion distribution showed Buddism(23.8%) as the most dominant. 50.7% of respondents married in the area. 2) Most households(91.5%) have lived in their own house in Sanpuk area. Average family size showed 4.3. More than half of residents(64.2%) have used public supplied water tap. Only 1.5% of the households had a flush toliet. The rest of households have still used primitive insanitary latrines. 3) 32.5% of residents have used gas burner for cooking and for heating in the house, and the coal briquet were used for boiler. Lack of convenient public transportation was the chief complaint for their day life. 4) Each household occupied 1,990 pyungs of rice paddy and 1,170 pyungs of ordinary field in average. Beside farming products, mushroom was the highest product. 5) Sixth percent of households in the survey area regularly participated in community meeting one hand and on the other hand 39.5% never participated. Most of respondents closely contacted with their neighbours and they seemed very friendly each other. 6) The prevalence rate of illness and injury during recent 15 days showed 48.3 per 1,000. The prevalence rate of chronic illnesses during the past one year showed 74 per 1,000. Injury and accident lead the higher portion(22.0%) in the former and in the latter pain(arthritis, back-pain) showed 27.0% as the dominant sickness. 87.8% of the ill residents in the former received medical treatment. As the most frequently utilized medical facility, the clinic or hospital were counted. Among the residents suffering from chronic illnesses, 77.3% in Sanpuk area get some kind of medical treatments and they rarely utilized the clinic or hospital. The reason why the patient did not receive any medical care was found out the fact that symptoms of illness was light or mild and economic problems was serious. 7) Average age of marriage showed 21.6 years old in the women and the average duration of marital period was shown for 15.1 years. The married woman in reproductive age in Sanpuk area had experienced pregnancies 4 times in the aver-age including 0.7 time of pregnancy in average were interrupted by induced abortion and 0.3 time by spontaneous abortion respectively. The practicing rate of the family planning of the married woman during reproductive ages showed 70.7% and the tuballigation was found out as the most frequently used contraceptives. 8) Among woman who has children under 2 years old, 70.0% had received the prenatal care for the last pregnancy. However, the average number of prenatal care visitis per woman showed 3.3 times. Fifty-two % of woman who received the postnatal care for the last delivery showed only 37.5%. 9) Immunization rate of the children under 2 years old showed relatively high and looked successful. The breast feeding for these children showed dominantly in the most. Most of the mothers in Sanpuk area had started the supplementary diet during weaning period of their infants of 6th and 7th month after birth. * : Sanpuk area is a demstration area for community development which has been supported by the Community Development Foundation during the part 10 years. The village is relatively closer to urban area such as Seoul, However, it has a similar characteristics shown as a remote village because of geographical location and inconvenient transportation at present.

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The Effect of Drought Simulated by Discharge Control on Water Quality and Benthic Diatom Community in the Indoor Experimental Channel (인공하천에서 유량감소로 모사한 가뭄효과가 수질 및 부착돌말류 군집에 미치는 영향)

  • Park, Hye-Jin;Kim, Baik-Ho;Kong, Dong-Soo;Hwang, Soon-Jin
    • Korean Journal of Ecology and Environment
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    • v.45 no.1
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    • pp.129-138
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    • 2012
  • We investigated an ecological impact of drought simulated by discharge depletion on the water quality and benthic diatom community in the indoor experimental channel. As artificial substrates slide-glass was installed in acrylic channel for 16 days. Channels were supplied continuously with eutrophic lake water with a discharge rate of 6 L $min^{-1}$ in duplication during the colonized period. And then during the discharge depletion period, three discharge rates were provided: NDF (No depletion of flow rate (Control): 6 L $min^{-1}$), LDF (Low depletion of flow rate: 3 L $min^{-1}$) and HDF (High depletion of flow rate: 1 L $min^{-1}$). Environmental factors in the water, such as suspended solid, Chl-$a$ and nutrients concentration, were measured with periphytic algae including AFDM (ash free dry matter), Chl-$a$ concentration and cell density at 1-day intervals. Light intensity increased significantly with discharge depletion (F=229.5, p= 0.000). $NH_4$-N concentration was highest at HDF. Suspended solid in outflowing water decreased at HDF (88%), LDF (97%) and NDF (99%), compared to inflowing water (100 %). Chl-$a$ in substrates increased more than two times at LDF and HDF than NDF (F= 8.399, p=0.001). Also AFDM and benthic diatom density increased significantly at LDF and HDF than NDF (F=9.390, p=0.001; F=6.088, p=0.007). In all experimental groups, $Aulacoseira$ $ambigua$, $Achnanthes$ $minutissima$ and $Aulacoseira$ $granulata$ were dominant species accounting for greater than 10% of benthic diatom density. The most dominant species, $A.$ $ambigua$ was highest at LDF, followed by HDF and NDF (F=8.551, p=0.001). In conclusion, the effect of drought simulated by discharge depletion in an artificial stream ecosystem caused significant changes on water quality and benthic diatom biomass. This result provides a useful data to understand the effect of draught on stream ecosystem in situ.

Characteristics of Fish Fauna and Community Structure in Wangpicheon (왕피천 어류상 및 어류군집의 특성)

  • Hong, Yang-Ki;Kim, Kyeong-Hwan;Kim, Kyeong-Moo;Lim, Gwang-Ho;Song, Mi-Young;Lee, Wan-Ok
    • Korean Journal of Environment and Ecology
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    • v.30 no.5
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    • pp.874-887
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    • 2016
  • We surveyed bimonthly from April to October 2015 to understand the fish fauna and community structure in Wangpicheon. The collected species during the survey period were 40 species belonging to 15 families. Dominant species by number were Zacco koreanus (31.3%) and Rhynchocypris oxycephalus (14.7%). In biomass, the dominant species were Z. koreanus (29.2%) and Coreoperca herzi (8.6%). Also, nine endemic species (22.5%) including Squalidus multimaculatus and two endangered species (Lethenteron reissneri, Cottus koreanus) were identified. It was identified one introduced species (Oncorhynchus mykiss) from foreign countries for aquaculture. Compared with previous data, nine species were newly identified including L. reissneri, S. gracilis majimae, Pseudobagrus fulvidraco, O. mykiss, Chelon haematocheilus, Siniperca scherzeri, Acanthogobius lactipes, Luciogobius guttatus and Channa argus. Seven species (Rhodeus ocellatus, S. gracilis majimae, Hemibarbus longirostris, Pseudogobio esocinus, Microphysogobio yaluensis, Hemiculter eigenmanni and Cobitis hankugensis) introduced from other native waters in Korea were estimated. According to the analysis of the habitat characteristics of major migratory species (Tribolodon hakonensis, O. keta and Plecoglossus altivelis), O. keta was observed at station 11 and T. hakonensis at station 7, 10 and 11. These fishes have been mainly identified in the downstream. However P. altivelis was widely distributed from station 3 to 11. In the comparison of average standard length of P. altivelis at each station during the same period, populations collected from station 3 and 5 which are mid-upper area of the stream were $125.8{\pm}34.2mm$. Their growth was good compared with those collected from station 8 and 11 (mid-lower area): $80.2{\pm}16.6mm$. This difference in length comes from the artificial structures including weir, thus it is necessary to create a fishway that enables P. altivelis to pass around barriers for free movement and resource management.

A Study of Fish Community on Up and Downstream of Hwabuk Dam Under Construction in the Upper Wie Stream. (위천 상류에 건설 중인 화북댐 상 하류 어류군집에 관한 연구)

  • Seo, Jin-Won;Kim, Hee-Sung
    • Korean Journal of Ecology and Environment
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    • v.42 no.2
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    • pp.260-269
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    • 2009
  • Hwabuk Dam has been under construction to reduce flood damage in Nakdong River watershed and to supply stable water for middle area of Gyeongbuk Province. Therefore, fish investigation in up and downstream of the dam was conducted from 2004 to 2008 in order to determine any negative effect on fish community due to dam construction and to use as fundamental data for conserving species diversity and maintaining stream health. According to data analysis on water quality, temperature, dissolved oxygen, pH, suspended solids, and total E-coli had seasonal variation, but they did not significantly differ in sites. However, biological and chemical oxygen demand, chlorophyll-a, nitrogen, and phosphorus representing organic matter and nutrient concentration were higher in upper site and decreased to lower site so that they differed by site. Concentration of arsenic among the heavy metals was less than 0.05 mg $L^{-1}$, which is regulated for protection of human health in water quality standard, except for 0.092 mg $L^{-1}$ in June 2005. During the study period, the total number of fish caught from the 6 sites was 10,263 representing 7 families 19 species. Among them, dominant and subdominant species were Korean chub (Zacco koreanus, 62.5%) and Chinese minnow (Rhynchocypris oxycephalus, 10.6%) which inhabit mostly in mid and upper streams, Korea. Among the 19 species, Korean endemic species were 9 species (47.4%) including Korean slender gudgeon (Squalidus gracilis majimae), Korean dark sleeper (Odontobutis platycephala), and Korean shiner (Coreoleuciscus splendidus). There was several individuals of the $1^{st}$-class endangered species, Naktong nose loach (Koreocobitis nahtongensis), caught in 2005${\sim}$2007, and no introduced species of fish was found in entire sampling period. According to result of community analysis, dominance index decreased toward lower site, but diversity and richness indices increased toward lower site. The equation of length-weight relationship on the dominant species was TW=0.000003$(TL)^{3.2603}$. The parameter b in the equation was greater than 3.0 indicating good nutritional condition in the populations. Compared to populations of Korean chub in other streams, the population in Hwabuk Dam watershed had higher mean of condition factor by size indicating better growth rate. With fish fauna and multi-metric health assessment model in each sampling attempt, index of biotic integrity (IBI) was evaluated and it resulted mostly in good (26${\sim}$35) and excellent (36${\sim}$40) condition in all sites, and the mean of IBI was the highest in site 5. The results indicate that it is very important to study not only environmental impact assessment with fish composition but also stream health assessment in order to conserve healthy aquatic ecosystem.

Fish Fauna and Community Structure in the Deogyusan National Park, Korea (덕유산국립공원의 어류상과 군집구조)

  • Yun, Seung Woon;Park, Jong Young
    • Korean Journal of Ichthyology
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    • v.33 no.2
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    • pp.126-141
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    • 2021
  • Fauna of freshwater fish and community structure were investigated at 13 sites in the Deogyusan National Park, Korea from 2014 to 2018. During the period, a total of 8 families, 21 species, and 8,716 individuals of fishes were collected. The number of fish collected over the past five years from 2014 to 2018, were 17 species and 2,280 individuals, 17 species and 1,579 individuals, 17 species 1,905 individuals, 17 species and 1,384 individuals, and 15 species and 1,568 individuals, respectively. There were 13 Korean endemic species including Iksookimia koreensis and Coreoleuciscus splendidus, etc. Only in Wondangcheon Stream, two endangered species were identified, and Hemibarbus mylodon was collected continuously except in 2015, and Pseudopungtungia nigra was observed every year. And two exotic species such as Oncorhynchus masou masou and Oncorhynchus mykiss occurred in Gucheongdongcheon Stream sites. The dominant species was Rhynchocypris oxycephalus and the sub-dominant species was Zacco koreanus and there was no difference by year. The fish community structure of Deogyusan National Park was varied depending on the sites and the year. Most of the survey sites located upper stream where the river structure is Aa river type showed poor community analysis results. On the other hand, the upper-mid stream sites including the Bb type showed better results. As a result, the Wondangcheon Stream sites had the most diverse and stable community structure. Similarity dendrogram was divided into 4 groups, mainly reflecting the characteristics of the habitat. The flagship species of the Deogyusan National Park, Rhynchocypris kumgangensis, was constantly observed during the investigation period. Compared to the previous survey, the number of species increased from 2004 (12 species) and decreased from 2009 (22 species).

Rates and Factors of Path Widening in Seongpanak Hiking Trail of Mount Halla, Jeju Island (한라산 성판악 등산로 노폭의 확대 속도와 요인)

  • Kim, Tae-Ho
    • Journal of the Korean Geographical Society
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    • v.43 no.3
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    • pp.296-311
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    • 2008
  • In order to examine the rates and factors of path widening in Mount Halla, the retreat of path sidewalls was monitored at 32 sites of Seongpanak Hiking Trail located between 875 m and 1,400 m in elevation. The mean rate of sidewall retreat for the period 2002-2008 is 50.6 mm, equivalent to 10.0 mm/yr. The retreat rate of frozen period is 19.3 mm/yr, while the rate of unfrozen period is 4.3 mm/yr. The latter is divided into the rainy and dry periods that exhibit the retreat rates of 5.9 mm/yr and 2.9 mm/yr, respectively. The retreat rate of sidewalls is also varied with seasons; winter shows the maximum rate of 42.2 mm/yr, while summer exhibits the minimum rate of 1.3 mm/yr. Spring and fall show the intermediate rates of 13.9 mm/yr and 6.4 mm/yr, respectively. Soil hardness and elevation are not closely related to the retreat rate of sidewalls, even though the retreat rate is larger at the north-faced sidewalls than the south-faced sidewalls during the frozen period. Pipkrake is likely to be the most important factor contributing to the path widening in that the retreat of winter months accounts for 76.7% of the total retreat. The hiking trail is placed under the climatic conditions which develop pipkrake in 85 days annually. In addition, it is usual to observe the path sidewall covered with pipkrake in the freezing month of December and the thawing months of March and April. On the other hand, deflation and rainsplash erosion are not important due to the weak wind speed and the forested trail. Rainwash is also insignificant in that the path has been almost paved to mitigate trampling effects. Although biological activity is not dominant, hikers cause a large retreat of sidewalls in the thawing months since they would walk on the sidewalls to avoid snow-melting pools on the path.

Korean Art from the view of foreigners in Korea from the period of independence to 1950s (광복 후부터 1950년대까지 한국에서 활동한 외국인이 본 한국미술)

  • Cho, Eun-Jung
    • The Journal of Art Theory & Practice
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    • no.4
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    • pp.123-144
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    • 2006
  • Foreigners who arrived in Korea after the age of enlightenment were Japanese, Chinese and 'Westerners' who were Europeans and Americans. The westerners were diplomats who visited Korea for colonization or for increasing their economical profits by trading after the spread of imperialism, and tourists curious of back countries, artists, explores and missionaries to perform their roles for their religious beliefs. They contacted with Korean cultural and educational people as missionaries and instructors during Japanese colonial period. In 1945, the allied forces occupied Korea under the name of takeover of Japanese colony after Japan's surrender and the relation between foreigners and Korean cultured men enter upon a new phase. For 3 years, American soldiers enforced lots of systems in Korea and many pro-American people were educated. This relationship lasted even after the establishment of the government of Korean Republic and especially, diplomats called as pro-Korean group came again after Korean War. Among them, there were lots of foreigners interested in cultures and arts. In particular, government officials under American Forces who were influential on political circles or diplomats widened their insights toward Korean cultural assets and collected them a lot. Those who were in Korea from the period of independence to 1950s wrote their impressions about Korean cultural assets on newspapers or journals after visiting contemporary Korean exhibitions. Among them, A. J. McTaggart, Richard Hertz and the Hendersons were dominant. They thought the artists had great interests in compromising and uniting the Orient and the West based on their knowledge of Korean cultural assets and they advised. However, it was different from Korean artist's point of view that the foreigners thought Korean art adhered oriental features and contained western contents. From foreigners' point of view, it is hard to understand the attitude Korean artists chose to keep their self-respect through experiencing the Korean war. It is difficult to distinguish their thought about Korean art based on their exotic taste from the Korean artists' local and peninsular features under Japanese imperialism. We can see their thought about Korean art and their viewpoint toward the third world, after staying in Korea for a short period and being a member of the first world. The basic thing was that they could see the potentialities through the worldwide, beautiful Korean cultural assets and they thought it was important to start with traditions. It is an evidence showing Korean artists' pride in regard to the art culture through experiencing the infringement of their country. By writing about illuminating Korean art from the third party's view, foreigners represented their thoughts through it that their economical, military superiority goes with their cultural superiority. The Korean artist's thought of emphasizing Korean history and traditions, reexamining and using it as an original creation may have been inspired by westerners' writings. 'The establishment of national art' that Korean artists gave emphasis then, didn't only affect one of the reactions toward external impact, 'the adhesion of tradition'. In the process of introducing Korean contemporary art and national treasure in America, different view caused by role differences-foreigner as selector and Korean as assistant-showed the fact evidently that the standard of beauty differed between them. By emphasizing that the basis to classify Korean cultural assets is different from the neighborhood China and Japan, they tried to reflect their understanding that the feature of Korean art is on speciality other than universality. And this make us understand that even when Korean artists profess modernism, they stress that the roots are on Korean and oriental tradition. It was obviously a different thought from foreigners' view on Korean art that Korean artists' conception of modernism and traditional roots are inherent in Korean history. In 1950s, after the independence, Korea had different ideas from foreigners that abstract was to be learned from the west. Korea was enduring tough times with their artists' self-respect which made them think that they can learn the method, but the spirit of abstract is in the orient.

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