• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.712-720
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• 2022

In this study, we evaluated the production and photoreactivity of CDOM of two polar phytoplanktons - Phaeocystis antarctica and Phaeocystis pouchetii, in order to find out UV effects on phytoplanktons. In visible region, CDOM in media of both phytoplanktons under UV-R decreased during 48hrs incubation period. However, in UV region CDOM decreased 30 % in the media of P. antarctica, but increased 10% in media of P. pouchetii, compared to CDOM concentrations of control after 48 hr incubation. This result indicates that biota in polar environment would not well protected from UV-R harmful effect when P. antarctica is dominant because of loss of CDOM, but when P. pouchetii is dominant species, production of UV absorbing organic matter could play more efficiently for UV screening for marine biota. Also we confirmed that FDOM of humic substance (C-peak) produced by these phtoplanktons under UV-R stress were well matched with fluorescence characteristics of the UV-protecting compound, MAAs. This finding shows that Phaeocystis pouchetti with low photoreactivity would contribute to DOM pool of polar marine environment under stratification by global warming.

• Journal of Aquaculture
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• v.17 no.2
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• pp.133-138
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• 2004

Haptophyte algae were collected at 67 sites in the East Sea, the Yellow Sea and the South Sea of Korea from October 2002 to April 2003. In the Yellow Sea, the seawater samples occasionally were collected in nearshore pools during low tide events. Haptophyte algae also were observed in samples from lagoons that contained some degree of salts from the East Sea. Haptophyte algae consisted of Prymnesium sp. of. parvum, Chrysochromulina spp. and Phaeocystis globosa.

• Ocean and Polar Research
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• v.32 no.4
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• pp.397-409
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• 2010

Herein, we compared the production rate of UV-absorbing compounds (mycosporine-like amino acids) and carotenoids in two phytoplankton species--Phaeocystis pouchetii and Porosira glacialis--which are the dominant species in Polar Regions under artificial UV radiation conditions. P. pouchetii exposed to UVR and PAR evidenced reductions in the carbon fixation rate, and was not significantly influenced by differing light conditions. However, the concentrations of UV-absorbing compounds and photo-protective pigments of P. pouchetii were increased with increasing exposure time, but P. glacialis maintained constant levels during the UVR exposure experiment. The production rates of MAAs showed a reverse phase between the two phytoplankton species. The carbon fixation rate of P. pouchetii cells was inhibited by exposure to UV radiation, but the production rates of MAAs in P. pouchetii were increased under UV radiation exposure. The carbon fixation rate and production rate of MAAs in P. glacialis were simultaneously inhibited under UV radiation exposure conditions. These results provide us with new information regarding the processes involved in the production of UV-absorbing compounds and photoprotective pigments in two phytoplankton species.

• Journal of Environmental Science International
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• v.20 no.11
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• pp.1357-1371
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• 2011

Suspended and sinking particles were collected during ODP Leg 119 to the Indian Ocean sector of the Antarctic Ocean. Field work was carried out at four sampling sites in Prydz Bay. Two of these sites were located in the Outer Bay, and two in the Inner Bay. At the four locations, a total of ten deployments of a sediment trap array were made. The concentrations of carotenoids both in suspended and sinking particulate matter in Prydz Bay were analyzed using HPLC. Fucoxanthin was the dominant carotenoid pigments both in suspended and sinking particles. The present study also indicates that 19'-hexanoyoxyfucoxanthin-containing prymesiophytes (Phaeocystis spp.) was abundant in the study area. The flux rates of carotenoids were generally highest at 50 m, and approximately double the flux rates at deeper horizons, however, at Inner Bay sites, the mean flux rates of carotenoids were greatest at 200 m, and 3 times greater than that of 50 m. Such anomalous high fluxes at 200 m imply that grazers were locally abundant between 100 m and 200 m at these sites close to land, and this hypothesis is supported by visual evidence of lots of fecal pellets in the 200 m trap. Integrates standing stocks versus sinking pigments data support that particulate material in Prydz Bay was not recycled rapidly.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.127-127
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• 2003

Haptophyta(이하 하프토조로 표기)는 그 일부종이 toxin을 가지며, 더욱이 이들 종들이 원인 생물로 발생하는 bloom으로 인한 경제적 피해 발생 등으로 인해 최근 여러 나라에서 활발한 연구가 이루어지고 있다. 남해안 일대의 몇몇 어ㆍ패류 양식장에서 이용하고 있는 식물먹이생물 및 동물먹이생물의 배양수조 내에서 배양을 목적으로 하는 먹이생물 이외의 혼재 생물의 종류를 조사하던 중 Haptophyta의 Prymnesium속 생물이 혼재하고 있는 것을 발견하였으며, 혼재된 Prymnesium은 양식 패류의 인공 종묘 생산 과정에서 사육 치패의 먹이로 이용되는 식물먹이생물 Isochrysis galbana의 증식을 크게 억제하였고, 더욱이 Prymnesium이 혼재된 Isochrysis galbana를 인공 종묘생산 중이던 치패에 투이한 결과 치패 모두가 폐사에 이르는 것을 관찰하였다. 이에 Isochrysis galbana의 배양 수조내에 Prymnesium이 혼입 하였을 경우 Isochrysis galbana의 증식양상을 알아보기 위해, Isochrysis galbana의 세포밀도를 5,440,000cells/ml로 하고 Prymnesium의 세포밀도를 10,000cells/ml로 하여 혼합 배양한 결과 배양개시 1일 후의 각 세포밀도는 Isochrysis galbana가 1,040,000cells/ml로 급격히 저하하였으며, 이와는 달리 Prymnesium은 50,000cells/ml로 증가하였다. 이들 종 각각의 증가 및 감소추세는 계속되어 배양개시 5일 후에는 Isochrysis galbana가 530,000cells/ml로 처음 배양당시 세포수의 90% 이상 감소하였고, Prymnesium은 43,333cells/ml로 4배 이상 증가하였다. 이 실험에서 Isochrysis galana의 세포수가 감소하는 이유는 정확히 알 수는 없으나, 하프토조의 일부 종에서는 광합성을 통한 유기물합성 이외에도 외부로부터의 DOC(dissolved organic carbon)를 직접 배양수로부터 취하거나 또는 영양염 제한 조건에서는 food particle을 섭취하는 경우가 있는 것으로 보고되고 있다. 한편, 이들 Haptopyta가 양식장에서 이용되어지는 해수를 통해 유입되는지를 알아보기 위해 모래여과조를 통과한 해수를 플랑크톤 배양용 배지의 첨가 없이 배양한 결과, Haptophyta의 Prymnesium, Chrysochromulina 및 Phaeocystis 둥의 수 종이 출현하였으며, 일부 종의 경우는 일정기간 지속적으로 배양되어짐을 알 수 있었다.

• Ocean and Polar Research
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• v.25 no.4
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• pp.625-631
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• 2003

While phytoplankton diversity and productivity in the Southern Ocean has been widely studied in recent years, most attention has been given to elucidating environmental factors that affect the dynamics of micro-plankton (mainly diatoms) and nano-plankton (mainly Phaeocystis antarctica). Only limited effects have been given to studying the occurrence and the potential risks associated with the blooming of dinoflagellates in the relevant waters. This study focused on the appearance and toxicological characteristics of a toxic dinoflagellate, Alexandrium tamarense, identified and isolated from the Drake Passage in a research cruise from November to December 2001 The appearance of A. tamarense in the Southern Ocean indicates the risk of a paralytic shellfish poisoning (PSP) outbreak there and is therefore of scientific concern. Results showed that while the overall quantity of A. tamarense in water samples from 30meters below the sea surface often comprised less than 0.1% of the total population of phytoplankton, the highest concentration of A. tamarense (20 cells $L^{-1}$) was recorded in the portion of the Southern Ocean between the southern end of South America and the Falkland Islands. Waters near the Polar Front contained the second highest concentrations of 10-15 cells $L^{-1}$. A. tamarense was however rarely found in waters near the southern side of the Polar Front, indicating that cold sea temperatures near the Antarctic ice does not favor the growth of this dinoflagellate. One strain of A. tamarense from this cruise was isolated and cultured for further study in the laboratory. Experiments showed that this strain of A. tamarense has a high tolerance to temperature variations and could survive at temperatures ranging from $5-26^{\circ}C$. This shows the cosmopolitan nature off. tamarense. With regard to the algal toxins produced, this strain of A. tamarense produced mainly C-2 toxins but very little saxitoxin and gonyailtoxin. The toxicological property of this A. tamarense strain coincided with a massive death of penguins in the Falkland Islands in December 2002 to January 2003.

• Ocean and Polar Research
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• v.27 no.3
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• pp.265-276
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• 2005

In order to grasp the structure and dynamics of phytoplankton communities, chlorophyll-a (Chl-a) and cell abundance were measured at 20 stations during the period from August 9 to August 21, 2003 in the southeastern Barents Sea on surface and subsurface chlorophyll maximum depth (SCM). Surface temperatures were varied from minimum $-0.7^{\circ}C(st. 18)$ to maximum $10.4^{\circ}C(st.1)$. Salinities were varied from minimum 29.9 psu(st. 18) to maximum 35.8 psu(st.2). The maximum nutrient(phosphate, nitrate, silicate) concentrations were $0.12{\mu}M,\;0.11{\mu}M,\;7.53{\mu}M$ and minimum concentrations were $0.01{\mu}M,\;0.03{\mu}M,\;1.43{\mu}M$, respectively. On SCM physical environmental factor were almost similar. Chl-a concentrations ranged from 0.23 to $2.13{\mu}g\;chi-a\;l^{-1}$ at SCM. Nano- and pico phytoplankton were the important contributors for increase of the Chl-a. It was about seven times difference between highest concentration to lowest. Phytoplankton communities were composed of diatoms, dinoflagellates, cryptophyceae, silicoflagellate, and prymnesiophyceae showing 37 taxa at surface and 38 taxa at SCM. Picophytoplankton was the most dominant in all stations and all layers, but the second groups were 2 and/or 3 taxa. Phytoplankton abundance ranged from minimum $4.3{\times}10^5\;cells\;l^{-1}$ (st. 20) to maximum $2.4{\times}10^6\;cells\;l^{\-1}$. (st. 17) at surface water. As a result, phytoplankton might be controlled by physical factors such as North Atlantic ocean currents and northern melt water among environmental factors in Barents Set h addition the dominant species were nano- and pico phytoplankton such as Phaeocystis, Cryptomonas and Dinobryon in the study area.