• Journal of Environmental Science International
• /
• v.6 no.3
• /
• pp.231-238
• /
• 1997

The community of phyloplankton and water quality were Investigated 5 times from October, 1994 to October, 1995 In the east area of Chinhae Bay. Seasonal changes of enoronmental parameters were shown general pattern and related to the red tide mechanism of phytoplankton community. Seasonal variations of dissolved oxygen concentrations were affected by the photosynthetic activity of phytoplankton community and the Increase of COD at the bottom water was occurred after the red tide. The standing stocks of phytoplankton In this study area ranged 202 - 1616 Cells . ml-1 and the bloom(red tide) was formed from April to July. The diatom species, Skeletonema costahm was a dominant species all the year round and the dinoflagellate species, Alexandrium tmuense and prorocentrum triestinum were red tide species Increased standing stocks in phytoplankton bloom.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.934-934
• /
• 2012

우리나라는 계절의 특성상 변동성이 심하고 경향성이 뚜렷한 특징으로 여름철에는 물이 풍부하여 홍수피해를 걱정하고 봄, 겨울에는 물 부족으로 걱정하는 것이 현실이다. 따라서 수자원 확보 및 관리를 위해서 정확한 유량을 측정하고 자료를 관리하는 것은 대단이 중요하다. 하천의 유량 산정시 실측유량을 통해 연속적인 하천의 유량자료를 산정하면 좋으나, 자연적, 외부적인 요건으로 인하여 기간분리가 발생한다. 이러한 경우 비유량을 적용하여 연속적인 유량자료를 생산해 내는 것이 하나의 대안으로 간주된다. 본 연구에서는 낙동강 유역을 중심으로 분석대상지점을 선정하고, 각각의 지점의 실측유량과 비유량을 각각 산정하여 비교분석을 실시하였다. 또한 상 하류간의 유역반응시간을 고려하여 비유량을 적용하고 적합도 평가를 실시함으로써 더욱 신뢰도 높고 안정된 유량자료의 산정과 평가를 실시하였다.

• Journal of the Speleological Society of Korea
• /
• no.88
• /
• pp.51-62
• /
• 2008

동굴내부의 지형변형은 동굴내의 외인적인 요인과 내인적인 요인에 의하여 발달된다. 외인적인 요인으로서 기후변동에 의한 기온의 변화와 침출수의 증감 및 외부 이입물질 등을 들 수 있으며, 내인적인 요인으로서는 암석의 공극율, 지질환경, 단층 및 습곡면의 형상, 절리 및 균열면의 유무, 동굴지천의 구배 및 유속, 층리간의 이종의 암석게재 여부 등을 들 수 있다. 동굴 시스템은 수문 물리화학적 요소에 의해 형성되며 외부 기준면 통제에 의해서 암석학, 구조학, 기후학, 생물학, 토양학 등과 밀접한 상태에서 의존적인 발달 과정을 가진다. 동혈 내부의 침식은 유수의 입력 경우 유출과정에서 형성되며, 또한 유수의 비 입력 경우유출 및 액체용액의 분출에 의해서 형성된다. 다수의 동굴학자들은 동굴은 계절마다 침수되거나 빨리 흐르는 홍수에 의한 폭우에 의해 epiphreatic 상태에서 간헐적으로 포화되는 과정을 거치며 선택적으로 발달한다고 주장하고 있다. 혼합지대 동굴의 가장 좋은 예는 현재의 카르스트 지역에서 나타나는 것이 아니라 과거 제4기의 200만년전 동안보다 해수면이 더 안정적이었던 때에 이루어진 고 카르스트(Paleo Karst)에서 발견되고 있다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.179-183
• /
• 2010

본 연구는 낙동강 중류 지역의 경북 구미시, 경북 왜관읍, 경북 성주군과 하류 지역의 경남 함안군, 창원시 북면과 대산면, 김해시 생림면의 하성충적층 내 지하수와 낙동강물의 연관성을 파악하였다. 중류와 하류지역에서 하성충적층의 주 대수층(모래자갈층)의 두께는 10m 내외로서 공간적으로 큰 차이를 보이지는 않는다. 하성충적층의 수리전도도는 $10^{-5}{\sim}10^{-3}$m/sec를 나타낸다. 하성충적층의 지하수위는 지역에 따라 해수면 기준으로 1.40~11.5m에서 변동하며, 지하수위와 낙동강 수위는 높은 상관성을 보인다. 지하수와 낙동강물의 화학분석 결과, 칼슘, 마그네슘, 나트륨, 칼륨, 염소, 규산, 중탄산, 망간, 철과 같은 무기성분의 농도는 지하수에서 더 높게 나타나고 있으나, 질산염의 농도는 낙동강물에서 더 높게 나타난다. 지하수내의 유기물질의 농도는 계절에 관계없이 비교적 일정하나, 낙동강물의 유기물질 농도는 우기보다 건기에 더 높은 경향성을 보이고 있다. 이러한 연구결과는 4대강 살리기 사업이나 하천주변지역의 수자원 개발에 활용될 수 있을 것이다.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.2
• /
• pp.252-263
• /
• 1997

Temperature and salinity were observed in Kugum Suro Channel in February, April, August and October 1993. Temperature ranged from $7.0^{\circ}C\;to\;25.0^{\circ}C$ throughout the year and its variation was about $18^{\circ}C$. The maximum temperature difference between surface and bottom was less than $0.75^{\circ}C$ for a year, which meant that the temperature stratification in Kugum Suro Channel was considerably week. Salinity had also a small variation range of less than $0.5\%_{\circ}$. Salinity varied from $34.0\%_{\circ}$ in April to $30.0\%_{\circ}$ in August and its fluctuation patterns were quite similar to the seasonal variations of the precipitation and the duration of sunshine observed at Kohung Weather station. Seasonal variation of sea water density in T-S diagram showed that the water mass in Kugum Suro Channel could be largely affected by regional atmospheric conditions. Temperature increased in ebb tide and decreased in flood tide, but salinity decreased in ebb tide and increased in flood tide for a day. The period of fluctuations in temperature and salinity measured for 25 hours was nearly coincident with the semi-diurnal tide which was predominant in that region. Stratification parameters computed in Kugum Suro Channel areas were less than $4.0J/m^3$ the year round, which indicated that vortical mixing from the bottom boundary caused by tidal current played an important role in deciding the stratification regime in Kugum Suro Channel. In estimating the equation which defines stratification and mixing effects in the observed areas, the tidal mixing term ranged from $4.7J/M^3\;to\;14.1J/m^3$ was greater than any other terms like solar radiation, river discharge and wind mixing.

• Korean journal of applied entomology
• /
• v.48 no.4
• /
• pp.447-451
• /
• 2009

Locust gall midge (LGM), Obolodiplosis robiniae (Haldeman) (Diptera: Cecidomyiidae), is a cecidomyiid insect forming roll-up galls on leaves of Robinia pseudoacacia Linnaeus (Fabaceae). LGM, known as native to North America, was reported from Korea and Japan in 2002. LGM was observed weekly or biweekly to clarify their voltinism and distribution within the crown of the host tree in two sites of Osan and Siheung in Korea from May to August, 2007. Density of LGM was investigated based on the number of larvae per leaf. Two generations of LGM were observed in Siheung site whereas three generations in Osan site during the present study. The result indicated that LGM had at maximum three generations per year. The density of LGM in Osan was higher in the upper crown of the host trees than middle or lower part. In Siheung, LGMs were distributed more on the exterior of the lower crown than the interior. The average number of larvae per gall was $3.3{\pm}0.1$ and $2.8{\pm}0.1$ individuals per leaf in Osan and Siheung, respectively.

• Economic and Environmental Geology
• /
• v.41 no.4
• /
• pp.393-403
• /
• 2008

Hydrogeochemistry of groundwater was studied in order to identify the influence of cow manure, distributed to a farmland as organic fertilizer, on nitrate concentrations in shallow groundwater and its spatio-temporal variations. From monitoring wells, water levels were measured using automatic data loggers, and water samples collected and analyzed in Feb., April, June and Oct. 2007. The average electric conductivity and concentration of nitrate in the groundwater show the highest levels in April and decline in subsequent sampling times. Decreases in dissolved oxygen(DO) and nitrate concentrations from April to Oct. and corresponding increases in $HCO_3$ concentrations indicate denitrification processes by microorganisms. Spatial variation of nitrate concentration appeared to be affected by the redox conditions of groundwater controlled by geochemical reactions of Mn, Fe and DOC contents.

• Korean Journal of Environmental Biology
• /
• v.22 no.1
• /
• pp.75-82
• /
• 2004

Surface and bottom sea water samples were harvested from the 5 stations in the marine ranching ground of Tongyeong coastal water from year 2000 to 2002. Cell number of heterotrophic bacteria was determined by using the plate counting method to explore the variation of the cell population of heterotrophic bacteria. Sea water samples collected in summer (in July and August) contained much larger number of heterotrophic bacteria than those harvested in spring, autumn and winter. Heterotrophic bacteria were usually more abundant in surface sea than in bottom sea water. However the reverse was true for sea water collected in December 2001 and February 2002 due to suspended solids accumulating more abundantly in seabed area because of the slower convective current of the sea water in winter. Number of heterotrophic bacteria did not have a strong relationship with frequency of typhoon indicating that the path and powerfulness of the typhoon, localized torrential downpour and temperature variation accompanying the typhoon should be considered all together at the same time as well as the frequency of typhoon to explain clearly the variation of cell number of heterotrophic bacteria. The dominant species isolated from the marine ranching ground of Tongyeong were identified to be Pseudomonas fluorescens, Pseudomonas stutzeri, Acinetobacter lwoffii and Sphingomonas paucimobilis.

• Journal of Conservation Science
• /
• v.29 no.4
• /
• pp.311-320
• /
• 2013

The showcase has insufficient temperature control, but it has excellent humidity control. The annual average temperature and relative humidity inside the showcase was $18.8^{\circ}C$ and 60.3%, respectively, and the showcase showed lower temperature and higher humidity than the exhibition room. The temperature inside the showcase appeared with high variation according to the seasons, while relative humidity was ranging from 59% to 61% regardless of the seasons. The showcase showed high temperature and humidity likewise the exhibition room in summer. In addition, lowering of temperature was elevated relative humidity according to the operation of air conditioner in summer. A moisture problem occurred because the temperature and humidity differences between the exhibition room and showcase were large according to the operation of air conditioner in winter. PI for temperature and relative humidity inside the showcase is 18.0%, and it means conservation environment for exhibition is unsuitable. In particular, continuous management of temperature and humidity inside the showcase is required because PI in the summer and winter is less than 1.0%.

• Journal of Aquaculture
• /
• v.8 no.1
• /
• pp.47-58
• /
• 1995

Field studies on the seasonal succesion of phytoplankton population were carried out at the 25 stations of the breeding ground in Kogum-sudo, Southern coast of Korean peninsula in Feburuary, April, August and October, 1993. Sixty four species belonging to 40 genera were identified. Predominant species were mainly centric diatoms throughout the four seasons, two centric diatoms, Skeletonema costatum and Thalassiosira sp. and a pennate diatom, Thaiassionema nitzschioides in the winter; two pennate diatoms, Thaiassionema nitzschioides and Asterionella kariana, and especially a dinoflagellate, Heterocapsa triquetra (station 10) in the spring, two centric diatoms, S. costatum and Chaetoceros diadema in the summer; and a centric diatom, Rhizosolenia alata and a pennate diatom, Bacillaria paxillifer in the fall. The main red tide organisms in the breeding ground were dinoflagellates, Prorocentrum dentatum, P. minimum, P. triestinum, Ceratium furro, Gymnodinium sanguineum, Noctiluca scintillans, H. triquetra, Scrippsiella trichoidea and a diatom S. costatum in the Kogum Sudo. Seasonal phytoplankton cell numbers were in a wide range between $8.8\times10^3$ cells/l and 1.4\times10^6$ cells/l; The seasonal average cell numbers were $12.2\times10^4\pm5.9\times10^4$ cells/l $(mean\;\pm\;standard\; diviation)$ in the winter, $3.3\times10^4\pm1.4\times10^4$ cells/l in the spring, $48.4X10^4\pm40.0\pm10^4$ cells/l in the summer, and $3.6\times10^4\pm1.9\times10^4$ cells/l in the fall, respectively.