• 제목/요약/키워드: Brackish

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한강 하구역 자치어 종조성의 계절 변동 (Seasonal Variation in Species Composition of the Larval Fish in the Han River Estuary, Korea)

  • 김지혜;김병기;한경남
    • 한국어류학회지
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    • 제26권2호
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    • pp.125-132
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    • 2014
  • 한강 하구역에서 출현하는 자치어의 시공간적 분포 특성을 파악하고 해양환경요인과 자치어의 분포 및 출현양상과의 연관성을 평가하기 위해 한강 하구역을 대표하는 염하수로, 석모수로, 장봉수로에서 2007년 5월에서 2008년 8월 사이 계절별로 자료를 수집하여 분석하였다. 연구기간 동안 자치어는 총 13개 분류군 총 3,642개체가 출현하였고, 웅어속이 48.8%로 우점하였다. 장봉수로에서 총 11개 분류군이 출현하여 가장 많았다. 석모수로에서는 웅어속이 대량 채집되어 채집량이 2,428개체로 가장 높았다. 춘계와 하계에 출현량이 증가하였으며, 동계에는 흰베도라치만이 출현하였다. 염하수로 및 석모수로에서는 기수종이 주를 이루었고 장봉수로에서는 연안성 어종, 연안 회유성 어종, 연안정착성 어종 등 다양하게 출현하였다. 정준대응분석(CCA) 결과 자치어는 수온 및 염분과 유의한 상관관계를 보였다. 한강 담수유입에 따른 염분에 따라 주요 자치어는 2개의 그룹(염하 석모수로, 장봉수로)으로 구분되었다.

국내에서 채집된 뱀장어 Anguilla japonica (Anguillidae)의 Silvering index와 생식소 발달 단계가 서로 다른 Pseudo-silver eels의 출현 (The Occurrence of Pseudo-silver eels with Different Silvering Index and Gonadal Development Stages in Anguilla japonica (Anguillidae) from Korean waters)

  • 홍양기;송미영;박희원;강정하;이완옥
    • 한국어류학회지
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    • 제29권2호
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    • pp.94-100
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    • 2017
  • 2014년 9월부터 2015년 8월까지 국내 9개 지점에서 채집된 Anguilla japonica 454개체의 생물학적 특성을 조사한 결과, silvering index (SI) 구분과 GSI의 차이가 큰 pseudo-silver eel이 소양호에서 2개체(PS1~PS2)와 금강하구에서 1개체(PS3)가 확인되었다. Pseudo-silver eel은 외부형태 기준으로는 S2 단계였으나, GSI, 소화관지수 (Gut index) 및 안경지수 (Eye index)에서는 모두 yellow eel 단계인 Y1 및 Y2였고, 생식소발달단계와 난경에서도 Y2 단계였다.

Development of the Pilot System for Radioactive Laundry Waste Treatment Using UV Photo-Oxidation Process and Reverse Osmosis Membrane

  • Park, Se-Moon;Park, Jong-Kil;Kim, Jong-Bin;Shin, Sang-Woon;Lee, Myung-Chan
    • Nuclear Engineering and Technology
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    • 제31권5호
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    • pp.506-511
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    • 1999
  • The pilot system for radioactive liquid laundry waste was developed with treatment capacity, 1ton/hr and set up in the Yong Kwang unit #4. The system is composed of tank module, RO systems and a UV/$H_2O$$_2$photo-oxidation unit. The RO system consists of the BW unit (low-pressure RO for brackish water desalination) and the SW unit (high-pressure RO for seawater desalination). The BW unit possesses 4 RO membranes and it can reduce the feed water volume down to 1/10. This concentrated feed water can be reduced again up to 1/10 in its volume in the SW unit composed of 4 RO membranes. The UV/$H_2O$$_2$ photo-oxidation process unit was used for the detergent degradation. The operation of the pilot system was carried out and verified in its capability through the continuous operation and concentration operation using the actual liquid waste from the power plant. The design criteria and data for industrialization were yielded. The efficiency of the UV/$H_2O$$_2$ photo-oxidation process and the optimum operational procedure were evaluated. The decontamination factors for radioactive cobalt and cesium were measured. This on-site test showed the experimental result in the DF$\geq$300 and volume reduction factor$\geq$100.

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가뭄 시 광역자치단체 별 물 비용 분석 및 해상 이동형 담수화 플랜트 이용 대응 방안 연구 (Cost analysis of water supply and development of desalination vessel as a drought response)

  • 양하연;구재욱;황태문;정성필
    • 상하수도학회지
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    • 제34권1호
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    • pp.53-60
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    • 2020
  • Due to global climate change, Korea is experiencing flooding and drought severely. It is hard to manage water resources because intensive precipitation during short periods and drought are commonly occurred in Korea, recently. Severe drought occurred in 2015 and 2017 in the islands, and coastal and inland areas in Korea, and the citizens experienced decreased water supply and emergency water service by using bottled water. Therefore, the Korean government provided additional governmental funds such as the grant of drought disaster. In this study, we tried to calculate the cost of water for drought response based on the cost of tap water for the regional local governments in Korea and the grant of drought disaster by the Ministry of the Interior and Safety in Korea, etc. The estimated costs of water for drought responses in coastal and inland areas which have a chance to apply alternative water sources such as brackish or seawater desalination and water reuse in Korea were higher than in other areas in Korea. Additionally, as the novel approach of drought response, the 300 ㎥/day-scale desalination vessel was suggested to provide desalinated water for the islands in Korea. The estimated expenses of water supply for the target island areas (Sinan-gun and Jindo-gun) by the desalination vessel was lower than those by emergency water service by using bottled water.

유해이형흡충(Heterophyes nocens)의 우리 나라 첫 유행지 발견 보고 (The first discovery of an endemic focus of Heterophyes nocens (Heterophyidae) infection in Korea)

  • 채종일;남형근
    • Parasites, Hosts and Diseases
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    • 제32권3호
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    • pp.157-162
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    • 1994
  • 전라남도 신안군 도서지역의 한 작은 해안 마을이 유해이형흡충(Heterophyes nocens)의 농후한 인체 감염 유행지임이 우리 나라에서 최초로 확인되었다. 1989년부터 1990년에 걸쳐 마을 주민 230명 중 98명의 대변을 수집하여 셀로판후층도말법 및 포르말린-에테르 집란법을 병행하여 검사한 바 이형홉충류(heterophylds) 충란이 42명(42.9%)에서 검출되었다. 그러나 충란만으로는 이형흡충류의 종(species)을 진단할 수 없어 충란 양성자들에 대해 praziquantel 10mg/kg과 하제를 투여한 후 설사변으로부터 성충을 회수하였다. 충란 양성 자 42명 중 프라지콴텔 및 하제 투여에 협력한 18명 전원으로부터 충체 회수를 완료할 수 있었고, 유해이형흡충 충체 1-1, 124마리(총 4,730마리)를 수집할 수 있었다. 감염자들은 대부 분 다른 이형흡충류(Pygidiopsts summa, Stictodora fuscatum 등) 및 큰입흡충류 (gymnophallid) 특히 Gymnophalloides seoi에 중복 감염되어 있었다. 이번 연구 결과로 미루어 보아 유해이형흡충은 중간숙주인 숭어. 문절망둑 등을 즐겨 생식하고 있는 우리 나라 남 해안 및 서해안의 해안 마을에 널리 분포하고 있을 것으로 추측되었다.

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Overview of the Fisheries and Aquaculture Resources in the Democratic Republic of Congo

  • Ekoma, Christian Ngunda;Mangala, Rapael Bukura
    • 한국해양바이오학회지
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    • 제3권1호
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    • pp.13-17
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    • 2008
  • The Congo has a maritime coastline of 40 km, covering an area of $2,345,409km^2$. The fluvial system covers around $34,000km^2$ in a network of more than 33,000 km of rivers, principal tributaries, and streams. There are around 1,000 known species of fish, essentially freshwater and some brackish. The lakes of the Rift Valley contain the richest lacustrine fauna in the world. The family of Cichlidae alone has more than 900 species. At the same time, the lakes are profoundly different. Lake Tanganyika has 250 species of fish, of which 216 are endemic, whereas Lake Kivu contains only 32 and 16, respectively. A dense hydrographic network of water surfaces, inundated plains and lakes cover around $86,080km^2$ (3.5% of the national area) and have a considerable aquatic potential. The large peripheral lakes of the East cover around $48,000km^2$ of which 47% are under Congolese jurisdiction. The respective areas belonging to the Congo are: Lake Tanganyika, $14,800km^2$; Lake Albert, $2,420km^2$; Lake Kivu, $1,700km^2$; Lake Edward, $1,630km^2$; Lake Mo$\ddot{e}$ro, $1,950km^2$. Another two important lakes in the interior, Lake Tumba and Lake Mai-Ndombe, cover (between them) 2,300 and $7,000km^2$, depending on season (less in the dry season and more in the rainy season). There are also the lakes of the Kamalondo depression ($6,256km^2$), Lake Tshangalele ($446km^2$) and Lake N'Zilo ($280km^2$).

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한반도 고해수면 변동 복원을 위한 규조-환경변수 상관관계 연구: 곰소만 동부 조간대 지역을 대상으로 (Study of the Correlation Between Diatom and Environmental Variables for Palao-Sealevel Reconstruction in the Korea Peninsula: Case Study of the Eastern Tidal Flat of Gomso Bay)

  • 김정윤;윤순옥;양동윤;황상일
    • 한국지형학회지
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    • 제24권2호
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    • pp.79-90
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    • 2017
  • This study investigated the correlation between the diatom community and the environmental variables on the tidal flat surface of the eastern part of Gomso Bay in the West coast of Korea in order to utilize the quantitative sea level record as a basic data. 24 sediment samples at 10cm intervals downstream of the Galgok Stream were used for diatom analysis, grain size analysis and CCA. As a result of diatom analysis, marine diatoms dominated at lower altitudes and the ratio of diatoms to fresh water diatoms and brackish diatoms increased toward upland. As a result of CCA, the contribution of environmental variables was analyzed as 25.3% at altitude, 21.6% at sand, 13.3% at skewness, etc. This means that altitude above sea level has the greatest influence on the diatom composition in the tidal flat surface. It suggests that the contribution of environmental variables at altitude above sea level can be used as a basic data for the quantitative records for reconstruction of paleo-sea level.

Environmental and Ecological Characteristics Influencing Spatial Distribution of Halophytes in Hampyeong Bay, Korea

  • Han, Sang-Hak;Choi, Chulhyun;Lee, Jeom-Sook;Lee, Sanghun
    • Proceedings of the National Institute of Ecology of the Republic of Korea
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    • 제2권4호
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    • pp.219-228
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    • 2021
  • During our observations of changes in halophyte distribution in Hampyeong Bay over a period of five years, we found that the distribution area showed a maintenance for Phragmites communis community, a tendency of gradual increase for Zoysia sinica community, gradual decrease for Suaeda maritima community, and disappearance for Limonium tetragonum community during the studied period. The Phragmites communis community stably settled in areas adjacent to land and appeared not to be significantly affected by physical factors (such as tides and waves) or disturbances caused by biological factors (such as interspecific competition). Among studied species, germination time was shown to be the fastest for Suaeda maritima. In addition, this species showed certain characteristics that allowed it to settle primarily in new habitats formed by sand deposition as its growth was not halted under conditions with high amounts of sand and high organic matter content. However, in areas where Zoysia sinica and Suaeda maritima resided together, the area inhabited by Suaeda maritima gradually decreased due to interspecific competition between the two species. This was believed to be the result of a sharp decrease in the germination of Suaeda maritima since May, while the germination of Zoysia sinica was continuously maintained, indicating that the latter had an advantage in terms of seedling competition. In the case of the Limonium tetragonum community, its habitat was found to have been completely destroyed because it was covered by sand. The study area was confirmed to have undergone a large change in topography as tides and waves resulted in sand deposition onto these lands. Hampyeong Bay is considered to have experienced changes in halophyte distribution related to certain complex factors, such as changes in physical habitats and changes in biological factors such as interspecific competition.

Developing a Virus-Binding Bacterium Expressing Mx Protein on the Bacterial Surface to Prevent Grouper Nervous Necrosis Virus Infection

  • Lin, Chia-Hua;Chen, Jun-Jie;Cheng, Chiu-Min
    • Journal of Microbiology and Biotechnology
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    • 제31권8호
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    • pp.1088-1097
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    • 2021
  • Grouper nervous necrosis virus (GNNV) infection causes mass grouper mortality, leading to substantial economic loss in Taiwan. Traditional methods of controlling GNNV infections involve the challenge of controlling disinfectant doses; low doses are ineffective, whereas high doses may cause environmental damage. Identifying potential methods to safely control GNNV infection to prevent viral outbreaks is essential. We engineered a virus-binding bacterium expressing a myxovirus resistance (Mx) protein on its surface for GNNV removal from phosphate-buffered saline (PBS), thus increasing the survival of grouper fin (GF-1) cells. We fused the grouper Mx protein (which recognizes and binds to the coat protein of GNNV) to the C-terminus of outer membrane lipoprotein A (lpp-Mx) and to the N-terminus of a bacterial autotransporter adhesin (Mx-AIDA); these constructs were expressed on the surfaces of Escherichia coli BL21 (BL21/lpp-Mx and BL21/Mx-AIDA). We examined bacterial surface expression capacity and GNNV binding activity through enzyme-linked immunosorbent assay; we also evaluated the GNNV removal efficacy of the bacteria and viral cytotoxicity after bacterial adsorption treatment. Although both constructs were successfully expressed, only BL21/lpp-Mx exhibited GNNV binding activity; BL21/lpp-Mx cells removed GNNV and protected GF-1 cells from GNNV infection more efficiently. Moreover, salinity affected the GNNV removal efficacy of BL21/lpp-Mx. Thus, our GNNV-binding bacterium is an efficient microparticle for removing GNNV from 10‰ brackish water and for preventing GNNV infection in groupers.

넙치자어에 대한 cyclopoid copepod, Paracyclopina nana 의 먹이효과 (Food Value of Cyclopoid Copepod, Paracyclopina nana for Flounder Paralichthys olivaceus Larvae)

  • 이균우
    • 한국산학기술학회논문지
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    • 제19권11호
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    • pp.682-687
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    • 2018
  • 본 연구는 넙치 (Paralichthys olivaceus) 자어에 대한 요각류 Paracyclopina nana의 먹이가치를 평가하기 위해 두섭식 단계 (rotifer 섭식 단계와 Artemia 섭식 단계)로 나누어 각각 12일 및 16일 동안 수행되었다. Rotifer 섭식 단계 실험에서, 넙치 자어의 생존과 성장은 부화 12일째 rotifer만 공급했을 때 보다 P. nana (nauplii) 단독으로 공급했을 때 더 높게 나타났다. Arteima 섭식단계 실험에서, 부화 30일째 넙치자어의 성장은 P. nana (C4-adult) 단독 공급실험구와 혼합공급(P. nana+Artemia) 실험구가 다른 실험구에 비해 높게 나타났으나 넙치 자어의 생존은 모든 실험구가 유의적인 차이를 보이지 않았다. P. nana nauplius와 성체(C4-adult)의 n-3 HUFA 함량은 각각 4.0%와 5.4%였다. 결과적으로, 기수산 요각류 P. nana는 해수어 종묘생산을 위한 초기생먹이로 효과적인 것으로 판단된다.