• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.10 no.1
• /
• pp.79-91
• /
• 2005

In order to understand growth characteristics of ten major species of microalgae responsible for frequent harmful algal blooms in Korean coastal waters, the growth rates of the isolates were examined in relation with the impacts of water temperature, salinity and irradiance. In addition, their bloom events since 1990 as well as monthly abundance of vegetative cells were analyzed. Heterocapsa triquetra, Eutreptiella gymnastica and Alexandrium tamarense were considered as relatively mid temperature adapted species in that growth rates were comparatively high at low water temperatures of $10{\sim}16^{\circ}C$ and drastically decreased at above $22^{\circ}C$. Prorocentrum micans and Pyramimonas sp. were categorized as relatively high temperature adapted species by showing comparatively better growths at high water temperatures above $25^{\circ}C$. Akashiwo sanguinea, Heterosigma akashiwo, Prorocentrum minimum and Scrippsiella trochoidea were eurythermal species with relative high growth rates in a broad ranges of water temperature, $16{\sim}25^{\circ}C$ were slightly halophobic, showing better growths at low salinities of $10{\sim}30$ psu than at above 35 psu. H. akashiwo, P. minimum and H. triquetra were euryhaline species with remarkable growths in a broad ranges of salinity, 15-40 psu. Frequent algal blooms by these three species at extremely low salinities below 25 psu after rainfall were attributed to their euryhaline and slightly halophobic physiological characteristics. Growth rates of H. akashiwo, P. minimum and Pyraminonas sp. increased with the increase of irradiance within the experimental ranges of $2{\sim}150\;{\mu}E{\cdot}m^{-2}{\cdot}s^{-1}$. However, A. sanguinea, A. tamarense and H. triquetra showed better growths at comparatively low irradiance of $50{\sim}100\;{\mu}E{\cdot}m^{-2}{\cdot}s^{-1}$ and drastic decreases in growth rates above $150\;{\mu}E{\cdot}m^{-2}{\cdot}s^{-1}$ of irradiance. Overall, relatively high temperature adapted species make blooms frequently in high water temperature season with strong natural irradiance, and relatively low temperature adapted species grow better at low water temperature with relatively weak natural irradiance.

• 한국해양학회지
• /
• v.28 no.3
• /
• pp.186-191
• /
• 1993

Scrippsiella trochoidea is a dinoflagellate responsible for red tide in early spring in southern coastal water. Marine bacteria appear to exert critical roles on the development and decay of phytoplankton bloom in marine ecosystem. It is likely that marine bacteria, Pseudomonas spp., share some metabolic processes with S. trochoidea. To investigate interactions between S. trochoidea and Pseudomonas spp. directly, cysts of S. trochoidea isolated from the bottom mud in Masan Bay have been germinated and cultured. From the S. trochoidea cultured medium, we have isolated Pseudomonas spp., a dominant and cultured. From the S. trochoidea cultured medium, we have isolated Pseudomonas spp., a dominant species. Both of Pseudomonas spp. and S trochoidea have been simultaneously inoculated into the sterilized sea water and cultured to examine the change of fatty acids. The major fatty acids that showed increases in composition during the dispecific culture were $C_{18:0/},{\;}C_{20:5}{\;}and{\;}C_{22:5}$ in S. trochoidea, and in Pseudomonas spp. Especially, $C_{20:5}{\;}and{\;}C_{18:0}$ were increased in S. trochoidea but decreased in Pseudomonas spp. These results strongly suggest that two species share some processes in their fatty acid metabolism.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.23 no.4
• /
• pp.303-309
• /
• 1990

To provide essential information of the role of marine bacteria on the dinoflagellate blooms, distribution of marine bacterial flora and dinoflagellate species was investigated in Chinhae Bay located in southern part of Korea from August 1989 to April 1990. Two hundred and fifty one strains of marine bacteria were isolated from seawater samples collected from the study area. Among them, Flavobacterium spp. and Acinetobacter spp. were the most dominant in bacterial flora. Another 32 strains which comprised 13 percent of total strains were Erythrobacter spp.. Based on the physiological character, Erythrobacter spp. were identified as Erythrobacter longus, Erythrobacter sp.(J-2) and Erythrobacter sp. (J-8). From the phytoplanktonic community, fourteen genera and twenty nine taxa of dinoflagellate species were identified. Based on the spatio-temporal frequence and abundance Gymnodinium sanguneum, Prorocentrum micans and Prorocentrum minimum were the aestival dominent species. However, Heterocapsa triquetra was appeared as predominant species in April. Cell density of about 2,000 cells/ml was prevailed in the bloom of August, but it developed into more intensive bloom of above 500 cells/ml in September. The water quality showed eutrophic or hypereutrophic condition, which was proved by high concentration of dissolved inorganic nitrogen, ortho-phosphate and chemical oxygen demand. Oxygen deficient water mass was found in the bottom overlying waters in August and September. High relationship between abundant bacterial flora and persistent dinoflagellate blooms in eutrophic condition would be approvable.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2000.10a
• /
• pp.133-134
• /
• 2000

최근 한국의 연안해역은 육상으로부터 오염물질의 다량유입과 자가오염으로 인하여 빈산소 수괴가 형성되고 있을 뿐만 아니라, 영양염류의 용출량 증가에 따라 부영양화가 가속화되고 있는 실정이다. 특히, 양식어장으로 장기간 사용되고 있는 내만 해역의 해저 퇴적물 오염은 적조발생과 같은 2차적인 문제를 야기 시키고 있어 해양환경 보존 및 수산생물 생산에 커다란 장해가 되고 있다. (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2000.10a
• /
• pp.148-149
• /
• 2000

연안해역은 육상환경과 해양환경이 상호작용하는 완충지역으로서, 양식어장, 항만, 해수욕장 등으로 이용되고 있다. 남해안과 같은 연안해역은 기초생산력이 아주 높고, 해면양식업에 적합한 지형적 여건을 갖추고 있어 옛부터 어패류 양식장으로 널리 이용되고 있다. 연안환경 특성에 따라 크게 2가지 유형 즉, 진해만과 같이 외부 부하량 증가로 적조가 상습적으로 발생하는 부영양화된 해역, 한산ㆍ거제만과 같이 외부 부하량 유입이 적고 기초생산력이 낮은 빈영양 해역으로 나누어진다. (중략)

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2003.08a
• /
• pp.194-198
• /
• 2003

내만(inner bay)과 내해(inland sea)에 다량의 질소, 인이 유입하면 식물플랑크들의 증식(적조현상)과 빈산소 수괴 현상 등의 수질문제가 발생한다. 이 때문에 본 연구가 대상으로 하는 Kitan(기담) 해협을 포함하는 Seto(뇌호)내해(inland sea)에 있어서는 1973년 Seto내해 환경임시조치법이 제정된 이후 정부차원에서 수질오탁의 원인이 되는 COD, 인 등의 총량규제가 실시되어 왔다. (중략)

• The Science & Technology
• /
• v.32 no.4 s.359
• /
• pp.76-77
• /
• 1999

과총의 Brain Pool 제도에 의해 97년 11월부터 성균관대 생물학과에서 이우성교수와 함께 공동연구를 진행중인 인도 과학자 마노하란박사는 '해양적조 유발성 조류의 환경적응에 관한 연구'로 좋은 성과를 얻고 있다. 마노하란박사는 "한국학자들은 실험테크닉을 비롯해 연구방법론에 대해서는 아주 우수한 것 같은데 정작 연구 자체에 대한 개념정립은 안돼 있는것 같다"고 지적하기도 했다.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.7 no.1
• /
• pp.13-21
• /
• 2004

Temporal changes of Chl-α, physical and chemical factors were investigated by diurnal observation at 2-hour interval at three fixed stations in the western Chinhae Bay from 12 Aug. to 13 Aug. 1999. Difference of dissolved oxygen between surface and bottom layer was maximum when the thermocline were strong. Organic distribution such as COD was affected by the growth of phytoplankton. Limitting factor was nitrogen, that is, inorganic nitrogen plays a significant role on regulating the algal growth. Surface distribution of dissolved inorganic nitrogen was very low compared to bottom layer by uptake of organisms. Maximum value of Chl-α at station C2 and C11 were observed from subsurface layer, ranges of which exceeded possibility concentration of red tide outbreak, 10 mg/㎥. On the other hand, that of C15 exist at surface layer. In this area, DIN and DIP concentrations increased by input sources such as rainfall and benthic flux before the bloom of phytoplankton. Accumulation of phytoplankton occurred at subsurface layer by the rapid uptake of DIN, especially nitrate ion, when strong thermocline existed as approach to the afternoon, which led to the increase of organics in water column and oxygen deficiency water mass at bottom layer until late at evening. Since then, DIN increases gradually as water temperature decrease to minimum. The quantitative understanding of nitrogen of fluxed to and from the various sources is necessary for environmental management.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.4
• /
• pp.331-338
• /
• 2000

The algicidal effects of marine bacteria were investigated and a strain, which had the strongest algicidal activity against the harmful dinoflagellate, Cochiodinim polykrikoides was selected. The bacterium was isolated in seawater during the period of blooming of C. polykrikoides in Masan Bay. This algicidal bacterium was identified as Micrococcus sp. LG-5 by means of morphological and biochemical tests. The optimal culture conditions of Micrococcus sp, LG-5 were $25^{\circ}C,\;pH 7.0\;and\;3.0{\%}$ NaCl concentration. The algicidal activity of Micrococcus sp. LG-5 was significantly increased to maximum value in the late of logarithmic phase of cell cuture. In addition, the culture filtrate ($pore size,\;0.1{\mu}m$) of Microcoocus sp. LG-5 showed strong algicidal effects. The cell numbers of C. polykikoides were decreased from $1.2{\times}10^4 cells/ml\;to\;less\;than\;2{\times}10^3\;cells/ml$ within 3, 6, 30 hours at the concentrations of culture filtrate $10{\%},\;5{\%}\;and\;1{\%}$, respectively. These results indicated that the algicidal effect was mediated by certain substances released from Microooccus sp. LG-5.

• Journal of Environmental Science International
• /
• v.8 no.1
• /
• pp.83-94
• /
• 1999

A Study on the choice of proper region for moving cage culture facilities were carried out in the South Sea of Korea. Optimum temperatures of habitats for cage culture fishes, Sebastes schlegeli, Paralichthys olivaceus, Seriola quinqueradiata, Lateolabrax japonicus, Pagrus major, Takifugu vermicularis, and Mugil cephalus were 18~26$^{\circ}C$, 10~$25^{\circ}C$, 15~29$^{\circ}C$, 15~29$^{\circ}C$, 15~3$0^{\circ}C$, 15~$25^{\circ}C$, and 19~27$^{\circ}C$, respectively. In winter, wintering regions for continuous growth of fishes were proper around Komundo, Sorido, Soimal, Gadukdo and Chejudo for Paralichthys olivaceus and Lateolabrax japonicus, while Seoguipo and Udo for Seriola quinqueradiata, Pagrus major and Takifugu vermicularis. Sanji was not proper for wintering region because variation of water temperature is large by effect of strong northwestern wind. Wintering regions of Sebastes schlegeli and Mugil cephalus were not in the south of Korea. In summer, proper regions for fishes to avoid from damage by red tide were Komundo and around Chejudo. No red tide has occurred in these regions for 6 years. Mokpo and Yoja Bay were not proper for moving region because the former had strong tides and the latter had only one exit out of the bay which made it impossible to move cages in other route when dangerous red tides burst into.