• ALGAE
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• 제20권3호
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• pp.207-216
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• 2005

Myrionecta rubra, a mixotrophic ciliate, is a cosmopolitan red tide species which is commonly found in neritic and estuarine waters. M. rubra had long been listed as an “nculturable protist”until 2 different laboratory strains were finally established in 2 research groups at the beginning of this century, enabling us to perform initiative investigation into various aspect of the live M. rubra strains (Gustafson et al. 2000; Yih et al. 2004b; Johnson and Stoecker 2005). Field sampling was carried out on high tide at 2 fixed stations around Kunsan Inner Harbor (St.1 near the Estuarine Weir and St.2 off Kunsan Ferry Station) every other day for 4 months from mid-February 2004 to understand detailed figure of the recurrent spring blooms of M. rubra following the onset of the water gates operation of the Keum River Estuarine Weir on August 1994. With its maximum abundance of 272 cells mL$^{-1}$ in St.1, fluctuation pattern of the M. rubra population at the 2 stations was strikingly similar. Notable growth of M. rubra population started on late April, to cause M. rubra red tides during one month from mid-May in which “xceptionally low salinity days”without its red tide were intermittently inserted. High abundance of M. rubra over 50 cells mL$^{-1}$ was recorded at samples with their water temperature and salinity higher than 15${^{\circ}C}$ and 4.0 psu, respectively. During pre-bloom period when salinity fluctuation is moderate and the water temperature is cooler than 15°C, Skeletonema costatum, a chain-forming centric diatom, was most dominant. Cyanobacterial species such as Aphanizomenon flos-aquae and Phormidium sp. replaced other dominant phytoplankters on the days with “xceptionally low salinity”even during the main blooming period of M. rubra. To summarize, M. rubra could form spring blooms in Keum River Estuary when the level of salinity fluctuation was more severe than that for the dominant diatom Skeletonema costatum and milder than that for the predominance by freshwater cyanobacteria. Therefore, optimal control of the scale and frequency of freshwater discharges might lead us to partially modify the fluctuation pattern of M. rubra populations as well as the period of spring blooms by M. rubra in Keum River Estuary. Sampling time interval of 2 days for the present study or daily sampling was concluded to be minimally required for the detailed exploration into the spring blooms by M. rubra populations in estuaries with weirs like Keum River Estuary.

• 환경생물
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• 제35권1호
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• pp.6-12
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• 2017

본 연구는 흰다리새우 초기유생이 (Postlarvae 15) 4 psu 저염분 순치 시 생리학적 변화에 관한 연구로서 순치방법, 즉 일반 해수를 비교구로 하고 8시간마다 빠르게 염분을 50%씩 감소를 한 실험구 (fast acclimation; F.A.)와 하루에 50%씩 천천히 염분을 감소시킨 실험구 (slow acclimation; S.A.)를 설정하여 생리학적 변화를 비교하였다. 생존율, gloucose와 혈중 요소성 질소의 함량이 순치방법에 따라 유의적인 차이를 보이지 않았으나 이온의 조성은 순치방법에 따라 차이를 보였다. 저염분에 순치된 새우의 체액 조성 중 마그네슘과 나트륨은 염분 32 psu에서 보다 낮은 농도를 보였다. 특히 나트륨 농도는 직접적으로 새우의 삼투압 조절에 영향을 미치는데 빠르게 순치를 시킨 F.A. 실험구에서 급격히 나트륨 농도가 감소하는 것으로 나타났다 (염분 32 psu에서 16 psu로 감소). 순치과정에서 새우의 스트레스를 줄이기 위해서는 처음 50% 염분을 감소시키는 과정은 8시간 이상으로 유지하고 그 이후에는 빠르게 순치하는 방법을 적용하는 것이 바람직할 것으로 파악되었다.

• Fisheries and Aquatic Sciences
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• 제3권3_4호
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• pp.222-227
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• 2000

Fabrea salina living at salt pond is an interesting ciliate in the research of photobiology and live food for aquaculture. This study was carried out to understand the natural habitat of F. salina at salt pond, which would be a basic biological knowledge for the indoor mass culture of this ciliate. In this research, the water quality as temperature, salinity, dissolved oxygen, and chlorophyll-a was examined with the population density of the ciliate at salt pond. The highest population density of F. salina occurred at 109 ppt and $31^{\circ}C$with 2,390 inds./L in August, and the distribution of the ciliate was positively correlated with salinity, temperature, and chlorophyll­a. Even though F. salina is a very euryharine ciliate, it did not occur at the salinity below 47 ppt in this study. Its reason is able to be explained with the occurrence of many predators as small fish and food competitors as zooplankton living at low salinity of salt pont. While F. salina occurred with Anemia at the same habitat using the same food source, the optimum salinity for the ciliate was a little higher than that of Anemia, and the optimum temperature for the former was a little lower than that of the later. This should be a reason for that these two species have different ecological nich at the same habitat using the same food source.

• 한국해양학회지:바다
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• 제27권1호
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• pp.17-32
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• 2022

2020년 8월 한국 남부해역 해양 조사를 통해 수집된 수온, 염분, 용존무기탄소(DIC), 총알칼리도(TA) 자료를 사용해서 표층수의 완충역량을 정량화하였다. 기존의 Revelle 인자의 문제점을 보완한 여섯 가지 완충 인자의 지리적 분포와 변동성을 분석하고, 수문학적 요인인 수온, 염분과의 관계를 논의하였다. 모든 완충인자들은 수괴에 따른 공간적 분포를 보였다: 완충역량은 용승이 발생했던 동해표층혼합수(ESMW)와 남해표층혼합수(SSMW)에서 낮았으며, 황해표층수(YSSW)에서는 중간값을 보였다. 또한 고온인 대마난류수(TWC)와 장강희석수(CDW) 순으로 크게 나타났다. 이는 하계의 장강유출수가 연구해역의 완충역량을 강화하는 것을 의미하며, 높은 수온과 생물학적 생산력, 하계의 성층화에 의한 혼합 약화가 원인으로 판단된다. 수온-완충역량은 수괴와 상관없이 유의한 양의 상관관계(R²=0.79)를 보였으나 염분-완충역량은 약한 음의 상관관계(R²=0.30)를 보였다. 높은 수온은 열역학적 과정인 기체 교환과 탄산계 화학종 분배를 통해 완충역량을 강화한다. 염분의 경우는 연구해역의 표층 염분이 증발이나 강수가 아닌 국지적인 담수의 유입과 용승수와의 혼합에 의해 변하므로 염분과 완충역량의 관계가 역전된다.

• 한국물환경학회지
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• 제34권1호
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• pp.77-83
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• 2018

This paper aims to evaluate the results of toxicity testing with Daphnia magna and Vibrio fischeri on wastewater samples which might be influenced by ion imbalance. The effluents from factories were found to be more toxic with high salinity levels than those from public wastewater treatment plant (WTP) and sewage treatment plant (SWP). Clion composition was highest in the effluent, in terms of percentage, which was followed by $Na^+$, $SO_4^{2-}$ and $Ca^{2+}$. $K^+$ and $Mg^{2+}$ ion was relatively low. The sensitivity of D. magna test results was higher than V. fischeri. Among samples which were proved by V. fischeri testing to be nontoxic, the composition ratio of each ion whether toxic samples or nontoxic samples which were decided by D. magna toxicity testing, were compared. $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$ ion composition ratio showed high level in nontoxic samples whereas $SO_4^{2-}$ and $Cl^-$ ion composition ratio was high in toxic samples. Accordingly, $SO_4^{2-}$ and $Cl^-$ ion seemed to be considered the ions causing toxicity in effluent. Toxicity from some categories of industries (Mining of non-metallic minerals, Manufacture of basic organic petrochemicals, Manufacture of other basic organic chemicals, Manufacture of other chemical products etc.) seemed to be influenced by salinity. The Ion concentration in influent and effluent were similar. Concentration of $Na^+$, $Cl^-$, $K^+$, $Ca^{2+}$ ions were high in influent, however $Mg^{2+}$ and $SO_4^{2-}$ ions were high in effluent.

• 한국농공학회논문집
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• 제60권3호
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• pp.113-121
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• 2018

The objectives of the research were 1) to develop the low-cost and high efficient desalination system to treat brackish water having high salt contents for irrigation at greenhouses near coast, and 2) to monitor and assess the effects of the brackish water desalination system on soil environment and growth in squash greenhouse cultivation area. The monitoring site was one of the squash greenhouse cultivation farm at Choengam-ri, Jinsang-myun, Gwangyang-si, Jeonnam-Do Monitoring results for groundwater irrigation water quality, and salinity showed a remarkable difference between control and treatment group. The salinity of soil at treatment group was less than at control group. While, the system made possible to increase the squash quantity from 4.7 ea to 6.3 ea at each and the average weight of the harvested squash was increased from 277.2 g to 295.1 g. The applied brackish water desalination system may be appled to reclaim sea or brackish irrigated area as alternative water resources, although long-term monitoring is needed to get more representative results at different level of salinity.

• 한국수산과학회지
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• 제54권4호
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• pp.456-466
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• 2021

The distribution and abundance of euphausiids were investigated in Korean waters in 2016. Euphausiids were sampled with a Bongo net. A CTD (Sea Bird Electronics 9 plus) measured the water temperature and salinity while sampling. Mean water temperature ranged from 4.2-31.0℃. The highest temperatures occur in September and lowest temperatures in February. The mean water salinity ranged from 27.9-34.8 psu, with the highest salinities in March and lowest in September. Euphausiid species in group W consisted of four species. Among the euphausiid species, Euphausia pacifica was the dominant species with peak densities in September. The E. pacifica from group W was distributed in the bottom cold water during summer when a thermocline was formed. Five euphausiid species occurred in group S. E. pacifica and E. nana were the dominant species. In group S, E. nana was located in the warm and saline Tsushima Warm Current, a branch of the influential Kuroshio Current. Five euphausiid species occurred in group E. E. pacifica and T. longipes were the dominant species. In group E, E. pacifica and T. longipes were distributed in the deep and cold waters, these species prefer low water temperatures and perform vertical migration. The distribution of euphausiids in Korean waters were highly influenced by mass water characteristics, such as temperature and salinity.

• 한국해양학회지:바다
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• 제18권4호
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• pp.178-185
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• 2013

해수의 염분 및 라돈($^{222}Rn$) 추적자를 이용하여 부산 인근의 동부와 남부 연안해역(문동리, 이천리, 죽성리, 대변리, 연화리, 다대포) 그리고 일광만 내에서 2009년과 2010년에 해저 용천수 유출 가능성을 조사하였다. 해양조사 전에 기본적으로 육상으로부터 해양으로 연장된 선구조 분석을 통하여 해저 용천수의 유출 유망지점을 선정하였다. 선정된 지점들을 포함하여 해안에서 바다쪽으로 약 1~2 km 이내에서 해수의 염분과 라돈을 측정하였다. 부산 인근의 동부 및 남부 연안해역에서 라돈 농도는 연안에서 외양쪽으로 갈수록 낮아지는 경향을 보였다. 또한, 염분의 수직분포에서는 일부 정점의 중간 수층에서 낮은 염분을 가진 수괴의 수평 유입이 관측되었다. 부산 인근의 동부 연안해역에서 유일한 만의 형태를 보이는 일광만 내에서 측정한 염분 수직분포에서도 저층에서 낮은 염분의 수괴가 출현하였다. 이번 조사에서 나타난 연구결과는 부산 인근 연안해역에서 해저 용천수 형태의 담지하수 유출 가능성을 시사하며, 앞으로 해저 용천수 탐사 방법과 미래의 대체 수자원으로서 활용 가능성에 대한 집중적인 연구가 필요할 것으로 판단된다.

• 한국수산과학회지
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• 제54권5호
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• pp.761-768
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• 2021

This study was carried out to identify an effective method to acclimate low-salinity (4 psu) bred Litopenaeus vannamei (mean body weight 16±3.3 g) to sea water. The fast acclimation group (FA) was directly exposed to filtered sea water (32 psu) while the slow acclimation group (SA) was exposed to a slow increase in salinity. Shrimps were sampled at 0, 1, 3, 6, 12, 24 and 48 h for plasma analyses. The plasma components between experimental groups did not show significant differences. The hemolymph osmolality (HO) in FA increased significantly after 1 h (P<0.05), while in SA it started to increase slowly only at 24 h and reached a similar level to that of FA at 48 h. The levels of Na⁺ and Mg²⁺ ions were significantly different between the two treatments (P<0.05), but there was no significant difference in Ca²⁺ ion levels. We found that the different methods of acclimation of L. vannamei to sea water do not affect the plasma components significantly, but lead to changes in the HO and ion levels, it is considerable to acclimate gradually for at least two days.

• 한국식품영양학회지
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• 제12권4호
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• pp.380-386
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• 1999

Fermented sausages inoculated with starter cultures which were combined Lactobacillus curvatus and Staphylococcus carnosus(LCSC), Lactobacillus plantarum and Staphylococcus carnosus(LPSC) were manufac-tured. changes in chemical composition salinity weight loss fatty acids inosine monophosphate(IMP) and hypoxanthine (Hx) and fee amino acids during ripening of fermented sausages were investigated. Due to drying the water content was decreased while the protein and fat contents salinity and weight low were increased during ripening. No significant differences between LCSC and LPSC were found for chemical composition salinity and weight loss. During ripening unsaturated fatty acid contents was dec-reased while saturated fatty acid contents was increased. At the end of the ripening the levels of mon-oenes were slightly higher in the LPSC than in the LCSC. In both treatments IMP contents were dec-reased but no changes were observed in Hx contents during ripening. Due to ripening the increase in total and individual free amino acids were observed and contents of glutamic acid alanine leucine and lysine were greatly increased.