• ALGAE
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• 제35권4호
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• pp.375-388
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• 2020

Ocean acidification and warming, identified as environmental concerns likely to be affected by climate change, are crucial determinants of algal growth. The ichthyotoxic raphidophytes Chattonella species are responsible for huge economic losses and environmental impact worldwide. In this study, we investigated the impact of CO2 on the thermal performance curves (TPCs) of Chattonella marina and Chattonella ovata grown under temperatures ranging from 13 to 34℃ under ambient pCO2 (350 μatm) and elevated pCO2 (950 μatm). TPCs were comparable between the species or even between pCO2 levels. With the exception of the critical thermal minimum (CTmin) for C. ovata, CTmin for C. marina and the thermal optimum (Topt) and critical thermal maximum (CTmax) for both species did not change with elevation of pCO2 levels. While CO2 enrichment increased the maximum photosynthetic rates (Pmax) up to 125% at the Totp of 30℃, specific growth rates were not significantly different under elevated pCO2 for the two species. Overall, C. ovata is likely to benefit from climate change, potentially widening its range of thermal tolerance limit in highly acidic waters and contributing to prolonged phenology of future phytoplankton assemblages in coastal waters.

• 한국수산과학회지
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• 제42권6호
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• pp.674-682
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• 2009

Recently, the occurrence of harmful algae blooms from the Chattonella group has been increasing and expanding in the southern and western seas of Korea. We investigated the relationship between growth kinetics and nutrients in the harmful algae Chattonella marina and Chattonella ovata of the South Sea, Korea. As a result; high concentrations of ammonium ($30\;{\mu}M$ and above) was not effective to the growth of C. ovata, while C. marina displayed good growth at concentration of $100\;{\mu}M$. The half-saturation constant ($K_s$) of C. marina for ammonium ($2.51\;{\mu}M$), nitrate ($5.36\;{\mu}M$) and phosphate ($0.75\;{\mu}M$) was higher than C. ovata (1.85, 4.01, and $0.61\;{\mu}M$, respectively). This indicates that C. ovata can achieve higher cell densities than C. marina under lower nutrient conditions. These $K_s$ values were comparatively higher than those of diatoms and other flagellates previously reported. Therefore, our results indicate that the growth of C. marina and C. ovata is less adapted to lower nutrient environments than other competition species, such as Skeletonema costatum and Cochlodinium polykrikoides.

• ALGAE
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• 제37권4호
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• pp.281-291
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• 2022

Quantifying the abundance of Chattonella species is necessary to effectively manage the threats from ichthyotoxic raphidophytes, which can cause large-scale mortality of aquacultured fish in temperate waters. The identification and cell counting of Chattonella species have been conducted primarily on living cells without fixation by light microscopy because routine fixatives do not retain their morphological features. Species belonging to the Chattonella marina complex, including C. marina and C. marina var. ovata, had high genetic similarities and the lack of clear morphological delimitations between the species. To estimate the abundance of C. marina complex in marine plankton samples, we developed a protocol based on the droplet digital polymerase chain reaction (ddPCR) assay, with C. marina complex-specific primers targeting the internal transcribed spacer (ITS) region of the rDNA. Cell abundance of the C. marina complex can be determined using the ITS copy number per cell, ranging from 25 ± 1 for C. marina to 112 ± 7 for C. marina var. ovata. There were no significant differences in ITS copies estimated by the ddPCR assay between environmental DNA samples from various localities spiked with the same number of cells of culture strains. This approach can be employed to improve the monitoring efficiency of various marine protists and to support the implementation of management for harmful algal blooms, which are difficult to analyze using microscopy alone.

• 한국해양학회지:바다
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• 제15권3호
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• pp.140-147
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• 2010

한국 남해에서 분리한 유해조류 Chattonella ovata의 성장에 미치는 수온과 염분 및 광량의 영향을 조사하였다. C. ovata는 $10{\sim}30\;^{\circ}C$의 수온과 7.5~40 psu의 염분조합 중 $10^{\circ}C$의 모든 염분조합과 $15^{\circ}C$의 7.5 psu와 10 psu, 그리고 $20^{\circ}C$와 $30^{\circ}C$의 7.5 psu를 제외한 모든 조합에서 성장하였다. 최대 성장속도는 $30^{\circ}C$, 30 psu 조합에서 $0.62\;day^{-1}$로 관찰되었다. 이원배치 분산분석(two-way ANOVA) 결과로부터 그들의 성장속도는 수온에 크게 의존할 뿐 염분과 교호작용의 영향은 미약하였다. 이와 같은 결과는 C. ovata가 고수온을 선호하는 광염성종임을 지시하였다. C. ovata는 $30\;{\mu}mol$ photons $m^{-2}s^{-1}$ 이하의 광량에서는 성장이 이루어지지 않았고, 본 연구에서 제공한 최대 광량인 $800\;{\mu}mol$ photons $m^{-2}s^{-1}$서 광 저해현상은 보이지 않았다. 광 조건에 의해 유도된 성장식 $\mu$=0.74(I-16.0)/(I+43.9)으로부터 성장에 대한 반포화광량($K_s$)은 $75.9\;{\mu}mol$ photons $m^{-2}s^{-1}$, 절대광량($I_c$)은 $16.0\;{\mu}mol$ photons $m^{-2}s^{-1}$로 나타났으며, 특히 $K_s$는 규조류인 Skeletonema costatum을 비롯한 다른 여러 편모조류보다 낮았다. 이상의 결과로부터 C. ovata는 하계 한국 내만과 연안해역에서 종간경쟁에 유리한 생리특성을 가진 종으로 판단되었다.

• 해양환경안전학회지
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• 제24권7호
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• pp.967-972
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• 2018

최근 우리나라 연안에서 출현빈도가 점차 늘어나고 있는 침편모조류에 속하는 Chattonella는 대표적인 유해조류 중 하나로, 이들 종은 세포벽이 없어, 단순히 세포의 형태나 크기 등 광학현미경 관찰만으로는 정확하게 동정하는 것이 어렵다. 따라서 본 연구에서는 2017년 득량만에서 발생한 Chattonella 적조 시료를 대상으로 단일 세포를 분리하고, 이들 시료의 28s rDNA, rbcL, psaA 영역을 대상으로 single-cell PCR 기법을 이용하여 종 동정을 실시하였다. 현미경 관찰 결과 장축은 평균 $74.0{\pm}10.1{\mu}m$이고 단축은 평균 $33.1{\pm}3.6{\mu}m$로 일반적인 Chattonella의 형태적 특징을 보였다. 28s rDNA, rbcL, psaA 영역을 대상으로 한 염기서열 비교 결과에서는 세 영역 모두에서 하나의 종으로 명확히 구분되지는 않았다. 하지만 C. marina, C. marina var. antiqua, C. marina var. ovata 그룹과 99~100 % 높은 서열 유사성을 보였다.

• 한국수산과학회지
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• 제43권4호
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• pp.362-372
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• 2010

In order to understand what leads to the appearance of harmful Chattonella algae in the Yeosu coastal waters of Korea, we measured environmental parameters every week at one station from May to November, 2006, and April to October, 2007. Four species of Chattonella appeared during the monitoring period: C. antiqua, C. globosa, C. marina and C. ovata. The range of water temperature and salinity were $15.0-27.9^{\circ}C$ and 17.6~33.0 psu, respectively, when Chattonella appeared, and their maximum cell density (4,840 cells/L) was at $27.1^{\circ}C$ and 33.0 psu. During the monitoring periods, the range of dissolved inorganic nitrogen (DIN), phosphate (DIP) and chlorophyll $\alpha$ (Chl-$\alpha$) concentrations in surface waters were $1.20-52.23\;{\mu}M$ ($8.59{\pm}8.97\;{\mu}M$), $0.03-1.56\;{\mu}M$ ($0.47{\pm}0.31\;{\mu}M$) and $0.45-31.12\;{\mu}g/L$ ($3.58{\pm}4.77\;{\mu}g/L$), respectively. Chattonella occurred at low cell density when the Chl-$\alpha$ concentration increased because of supplied nutrients, whereas their cell density increased during the periods of rapid decrease in Chl-$\alpha$. The results of growth experiments based on batch culture showed that the half saturation constant ($K_s$) of C. antiqua on ammonium (${NH_4}^-$), nitrate (${NO_3}^-$) and phosphate (${PO_4}^{2-}$) were $3.89{\mu}M$, $5.01\;{\mu}M$ and $0.63\;{\mu}M$, respectively. These Ks values are higher than those reported for diatoms and other flagellates at the DIP concentration (average $0.47{\mu}M$) of Yeosu coastal waters. Although the maximum specific growth rate (${\mu}_{max}$) of C. antiqua was lower than diatoms, it was higher than those of other flagellates. Therefore, our results indicate that the DIP level in the study area was too low to support Chattonella blooms, although Chattonella species have physiological characteristics that enable them to grow more rapidly than other flagellates when nutrient levels are higher than their $K_s$.