• Ocean and Polar Research
• /
• 제41권2호
• /
• pp.107-120
• /
• 2019

The frequency analysis of scientific terms using bibliographic information is a simple concept, but as relevant data become more widespread, manual analysis of all data is practically impossible or only possible to a very limited extent. In addition, as the scale of oceanographic research has expanded to become much more comprehensive and widespread, the allocation of research resources on various topics has become an important issue. In this study, the frequency analysis of scientific terms was performed using text mining. The data used in the analysis is a general-purpose scholarship database, totaling 2,878 articles. Hypoxia, which is an important issue in the marine environment, was selected as a research field and the frequencies of related words were analyzed. The most frequently used words were 'Organic matter', 'Bottom water', and 'Dead zone' and specific areas showed high frequency. The results of this research can be used as a basis for the allocation of research resources to the frequency of use of related terms in specific fields when planning a large research project represented by single word.

• 환경생물
• /
• 제40권4호
• /
• pp.510-524
• /
• 2022

2011년 2월부터 2012년 11월까지 진해만에 23개 정점을 선정하여 저서오염지수를 이용하여 대형저서동물의 군집건강도를 평가해 보았다. 그 결과, 거제도 북쪽과 칠천도 부근의 정점을 제외한 모든 진해만 해역에서 저서동물군집의 건강도가 4~5등급으로 매우 오염된 상태인 것으로 나타났다. 특히 마산만과 고성만, 통영만의 일부 정점들에서는 기회종이 속한 4그룹의 비중이 90% 이상으로 나타났는데, 이는 저서환경이 오염되어 있음을 시사한다. 진해만에서는 마산만, 행암만, 통영만, 고현만에서 여름철 hypoxia 현상으로 인해 무생물 상태를 보였고, 종료 후 기회종이 대량 가입하는 양상을 보였다. 하지만 hypoxia 후 기회종이 가입되지 않은 일부 정점들이 관찰되었고, 이로 인해 저서건강도가 과대평가되는 현상에 대한 추가 연구가 필요할 것으로 판단된다. 진해만의 저서건강도는 경기만의 시화호, 부산항만 등 다른 특별관리해역들에 비해서도 매우 낮게 나타나 심각하게 오염된 저서환경임을 시사하였다.

• 한국패류학회지
• /
• 제29권3호
• /
• pp.239-244
• /
• 2013

Mass mortalities of farmed shellfish, mostly in summer season, thus named mass summer mortalities, have been a global issue in shellfish aquaculture. The 2013 mass summer mortalities in the confined waters of Goseong Bay, Goseong, Korea were quite a unique and intensive for two farmed species, the Pacific oysters, Crassostrea gigas, and bay scallops, Argopecten irradians. The mortalities were progressive from the bottom of the suspended oysters and caged scallops in the waters, reaching up to 80% for the oyster and 95% for the scallop in about 20 days after the first occurrence, early August, 2013. We monitored a wide range of environmental factors, including water temperature, dissolved oxygen (DO), salinity, turbidity, acidity (pH), organic and inorganic matters, chemical oxygen demand (COD), suspected pathogenic agent, and phytoplankton composition throughout the water column where the two species were suspended or caged. Our survey concluded that the hypoxia or anoxia might be a major cause of the mortalities. Here, we detailed the mortalities and ways to arrive at the conclusion.

• 한국해양생명과학회지
• /
• 제1권1호
• /
• pp.25-30
• /
• 2016

본 연구는 소형화된 홀 소자를 이용하여 국내 패류 양식 생물 중 가장 많은 생산량을 보이는 참굴(Crassostrea gigas)의 패각운동을 기초로, 연안역에서 빈산소에 대한 생물모니터링 시스템의 적용 가능성을 조사하였다. 정상상태 패각운동의 측정을 위해서 여과해수에서 측정한 결과, 참굴 개체는 평균 5~12 mm 정도의 개각상태를 유지하였으며, 패각운동 시 비교적 빠른 폐각상태를 보였다가 느린 속도의 개각상태의 운동이 관찰되었다. 하지만, 주·야간 사이에는 큰 차이가 없었다(p<0.05). 용존산소 농도를 7 mg l^-1에서 3 mg l^-1까지 감소시키면, 패각운동의 횟수는 증가를 나타내었으며, 파형도 정상상태와 다르게 불안정한 파형을 보였다. 또한 용존산소가 2 mg l^-1로 감소된 후에는 패각운동의 크기가 점차 작아지거나, 폐각상태를 지시하는 파형이 관찰되었다. 이와 같은 생물모니터링 시스템을 패류 양식에 활용하여 빈산소와 같은 해양환경의 이상변동을 신속히 감지할 수 있다면, 어업피해를 감소시킬 수 있을 것으로 기대된다.

• 환경생물
• /
• 제33권4호
• /
• pp.412-418
• /
• 2015

$12^{\circ}C$에서 DO 농도가 $0.7mg\;L^{-1}$일 때 조피볼락의 폐사가 발생하였으며, 소요시간은 274분이었다. $20^{\circ}C$에서는 DO 농도가 $0.8mg\;L^{-1}$일 때 조피볼락의 폐사가 발생하였으며, 소요시간은 148분이었다. DO 농도의 감소는 스트레스 요인으로 작용하여 $12^{\circ}C$와 $20^{\circ}C$에서 1차적으로 코티졸 및 글루코스 농도를 상승시켰다. 또한 Ht, Hb, AST, ALT, 이온 농도, 삼투질 농도도 $12^{\circ}C$와 $20^{\circ}C$에서 폐사 직전에 증가하는 경향을 보였다.

• Toxicological Research
• /
• 제19권2호
• /
• pp.99-104
• /
• 2003

This study was aimed to evaluate the effect of oxygen on motor activity and toxicity in male mice. The modified Porsolt forced swim test (FST) was used and the distance and time of movement by mice were analyzed in 15。C water bath for 20 minutes using the automatic Ethovision videotracking system. Analyses were carried out before and after 20 minutes of exposure to 10％-70％ concentration of normobaric oxygen. The effects of inspired oxygen tension on the distance and time of movement showed the similar trends, but changes in distance were more prominent. Both the distance and time of movement increased after exposure to 30％ and 40％ oxygen concentration. The distance and time of movement also increased upon exposure to 50％ and 60％ oxygen. In contrast, increases En movement and time under exposure to 21％ oxygen concentration were suppressed when exposed to over 50％ oxygen concentration. With exposure to 10％ oxygen, there was a significant decrease in the distance of movement and a slight suppression of movement time. During the swim test, 12.5％, 37.5％, and 87.5％ of the mice drowned after exposure to 10％, 60％, and 70％ oxygen concentration, respectively. These results suggest that motor activity can be enhanced by inspired oxygen up to 40％ concentration. When hypoxic and hyperoxic oxygen exposure over 50％, motor activity is reduced and toxicity may be induced.

• 동의생리병리학회지
• /
• 제17권6호
• /
• pp.1433-1440
• /
• 2003

This research was performed to investigate protective effect of Sophorae subprostratae Radix and each fractions against ischemic damage using PC12 cells. To observe the protective effect of Sophorae subprostratae Radix on ischemia damage, vibility and changes in activities of Superoxide dismutase (SOD), Glutathione Peroxidase (GPx), Catalase and Production of Malondialdehyde (MDA) were observed after treating PC12 cells with Sophorae subprostratae Radix during ischemic insult. Groups were divided into five groups: no treated (Normal), hypoxia chamber for 48hrs followed by 6h at normoxic chamber (H/R), Sop horae subprostratae Radix total phase treated group with H/R (Total), Sophorae subprostratae Radix water phase treated group with H/R (Water), Sophorae subprostratae Radix BuOH phase treated group with H/R (BuOH), Sophorae subprostratae Radix alkaloid phase treated group with H/R (Alkaloid). The results showed that (1) in hypoxiajreperfusion model using PC12 cell, the Sophorae subprostratae Radix has the protective effect against ischemia in the dose of 0.2 ㎍/㎖, 2 ㎍/㎖ and 20 ㎍/㎖, (2) Sophorae subprostratae Radix increased the activities of glutathione peroxidase and catalase. (3) the activity of Superoxide Diamutase(SOD) increased by ischemic damage, which might represent the self protection. This study suggests that Sophorae subprostratae Radix has neuroprotective effect against neuronal damage following hypoxiajreperfusion cell culture model using PC12 cell and dose dependency effects. In conclusion, Sophorae subprostratae Radix has protective effects against ischemic oxidative damage at the early stage of ischemia.

• 생명과학회지
• /
• 제19권1호
• /
• pp.21-33
• /
• 2009

대황(Rhei Rhizoma; RR, 대황(大黃))은 Rheum officinale Baill.와 Rheum palmatum L.(polygonaceae)의 땅속부분으로 남아시아의 민속의학에서 간 및 신장의 손상을 치료하는데 널리 이용되고 있다. 본 연구에서는 배양한 흰쥐 해마신경세포의 저산소증모델을 이용하여 대황의 물추출물이 유전자 표현에 미치는 영향을 microarray 방법을 이용하여 조사하였다. 배양 후 10일 (DIV10)에 추출물을 배지에 $2.5{\mu}g/ml$ 농도로 첨가하고, DIV13에 저산소증(2% $O_2$/5% $CO_2$, $37^{\circ}C$, 3 h)을 유발한 후 24 시간 후에 total RNA를 분리하여 microarray에 사용하였다. MA-plot에 의하면 표현이 연화된 대부분의 유전자는 ${\pm}2$배 이내로 증감되었다. 이 가운데 Global M 값이 0.2(즉, 15%)보다 더 증가한 유전자는 472종, Global M 값이 -0.2(즉, -15%)보다 더 감소한 유전자는 725종이였다. 세포의 생존과 관련된 유전자 가운데 세포자연사 억제유전자인 Tegt(2.4배), Nfkb1 (2.4배), Veg (1.8배), Ngfr (1.6배) 등이 크게 증가하였으며, 반면에 자연사 촉진유전자인 Bad (-64%), Cstb (-66%)는 감소하였다. 스트레스를 극복하는데 필요한 유전자인 Defb3 (2.7배), Cygb (2.2배), Ahsg (2.18배), Alox5 (2배) 등도 크게 증가하였다. 그리고 세포 성장을 촉진하는 유전자인 Erbb2 (1.84배), Mapk12 (1.8배)도 크게 증가하였다. 따라서 대황의 물추출물은 세포생존에 필요한 유전자를 증가시키고, 세포사를 유도하는 유전자는 감소시킴으로서 저산소층 스트레스에서 신경세포의 사망을 억제하는 것으로 해석된다.

• 생태와환경
• /
• 제38권spc호
• /
• pp.39-43
• /
• 2005

The dynamics of water quality with the storm events were analyzed in a small reservoir for irrigation, Lake Wangkung. Water quality of the inflowing stream fluctuated seasonally with the variation of flow rate. Thermal stratification was consistent from April to October below 2 m depths and anoxic layer was developed below 2 m depth in summer. The unique feature of temperature showed that thermal stratification was disrupted by a heavy rain event during monsoon, but hypolimnetic hypoxia were reestablished after a few days. Phosphorus and nitrogen increased immediately following storm events. The marked increase may be due to the input of P-rich storm runoff from the watershed. Internal phosphorus loading can be one of the explanations for TP increases in summer. When there was a storm, total populations of phytoplankton and zooplankton was reduced immediately following the storm, indicating possible flushing of algae and zooplankton. After a lag period of low-density the plankton population bloomed to a peak again within five days after the storm. Turbid water in lake became clear again which coincided with the time of the phytoplankton buildup. The results demonstrate that water quality is regulated greatly by rainfall intensity in Lake Wangkung.

• 한국물환경학회지
• /
• 제37권6호
• /
• pp.425-432
• /
• 2021

A tidal power plant (TPP) has been in operation since the end of 2011 to improve the water quality of Shihwa Coastal Reservoir (SCR). Tidal mixing rate increased 5.6 times after the TPP operation so that in this study, its effects on water quality was assessed through statistical analysis of long-term water quality monitoring data. It was found that the increased tidal mixing contributed to solving the hypoxia problem in the bottom water by preventing the summer stratification. The analysis also showed that the increased tidal mixing had different effects depending on the relative concentration difference for each water quality substances between the SCR and the outside of SCR. The average concentrations of some substances (chemical oxygen demand, total phosphorus, chlorophyll-a) with higher concentrations than the outside of SCR decreased due to the dilution effect, but the other substances (total nitrogen, dissolved inorganic nitrogen, dissolved inorganic phosphorus) with lower concentrations compared to the outside ones increased on the contrary. Factor analysis also showed a consistent result that the first factor accounting for the water quality was changed from the organic-related substances to the nutrient-related substances after the increased tidal mixing. These results imply that the focus of future water quality management needs shifting from the organic substances to the nutrients, particularly dissolved inorganic nutrients. Considering the effect of inflow seawater on the nutrients, the management area should be extended to cover not only SCR but also a certain area outside of SCR.