<i>Islandinium minutum</i> subsp. <i>barbatum</i> subsp. nov. (Dinoflagellata), a New Organic-Walled Dinoflagellate Cyst from the Western Arctic: Morphology, Phylogenetic Position Based on SSU rDNA and LSU rDNA, and Distribution

Potvin, É,ric,Kim, So-Young,Yang, Eun Jin,Head, Martin J.,Kim, Hyun-cheol,Nam, Seung-Il,Yim, Joung Han,Kang, Sung-Ho Wiley (Blackwell Publishing) 2018 JOURNAL OF EUKARYOTIC MICROBIOLOGY - Vol.65 No.6

Feeding by heterotrophic protists and copepods on the photosynthetic dinoflagellate Azadinium cf. poporum from western Korean waters

Potvin, E.,Hwang, Y.J.,Yoo, Y.D.,Kim, J.S.,Jeong, H.J. INTER-RESEARCH 2013 Aquatic microbial ecology Vol.68 No.2

Morphology, molecular phylogeny, and pigment characterization of an isolate of the dinoflagellate Pelagodinium bei from Korean waters

Potvin, Eric,Jeong, Hae Jin,Kang, Nam Seon,Noh, Jae Hoon,Yang, Eun Jin The Korean Society of Phycology 2015 ALGAE Vol.30 No.3

The dinoflagellate genus Pelagodinium is genetically classified in distinct sub-clades and subgroups. However, it is difficult to determine whether this genetic diversity represents intra- or interspecific divergence within the genus since only the morphology of the type strain of the genus Pelagodinium, Pelagodinium bei, is available. An isolate associated with the genus Pelagodinium from Shiwha Bay, Korea, was recently cultured. This isolate was clustered with 3 to 4 strains from the Atlantic Ocean, Mediterranean Sea, and Indian Ocean. This cluster was distinct from the subgroup more closely associated with P. bei. The morphology of the isolate was analyzed using optical and scanning electron microscopy and was almost identical to that of P. bei except that this isolate had two series of amphiesmal vesicles (AVs) in the cingulum, unlike P. bei that has one series. When the pigment compositions of the isolate and P. bei were analyzed using high-performance liquid chromatography, these two strains had peridinin as a major accessory pigment and their pigment compositions were almost identical. In addition, the swimming behaviors of these two strains were very similar. The reexamination of the type culture of P. bei revealed two series in the cingulum as for the isolate. The new findings on the number of series of AVs in the cingulum, the pigment composition, and the swimming behaviors suggest that P. bei and the isolate are conspecific despite their genetic divergence. This study provides a basis to further understand the molecular classification within Pelagodinium combining genetic, morphological, pigment, and behavioral data.

Morphology, molecular phylogeny, and pigment characterization of a novel phenotype of the dinoflagellate genus Pelagodinium from Korean waters

Éric Potvin,정해진,Nam Seon Kang,JAE-HOONNOH,양은진 한국조류학회I 2015 ALGAE Vol.30 No.3

The dinoflagellate genus Pelagodinium is genetically classified in distinct sub-clades and subgroups. However, it is difficult to determine whether this genetic diversity represents intra- or interspecific divergence within the genus since only the morphology of the type strain of the genus Pelagodinium, Pelagodinium bei, is available. An isolate associated with the genus Pelagodinium from Shiwha Bay, Korea, was recently cultured. This isolate formed a subgroup with 3 to 4 strains from the Atlantic Ocean, Mediterranean Sea, and Indian Ocean. This subgroup was distinct from the subgroup containing P. bei. The morphology of the isolate was analyzed using optical and scanning electron microscopy and was almost identical to that of P. bei except that this isolate had two series of amphiesmal vesicles (AVs) in the cingulum, unlike P. bei that has one series. When the pigment compositions of the isolate and P. bei were analyzed using high-performance liquid chromatography, these two strains had peridinin as a major accessory pigment and their pigment compositions were almost identical. In addition, the swimming behaviors of these two strains were very similar. The re-examination of the type culture of P. bei revealed two series in the cingulum as for the isolate. The new findings on the number of series of AVs in the cingulum, the pigment composition, and the swimming behaviors suggest that P. bei and the isolate may be conspecific despite their association to genetically different subgroups. This study provides a basis to further understand the molecular classification within Pelagodinium combining genetic, morphological, pigment, and behavioral data.

탄소 배출 시나리오를 통한 고등학생들의 탄소 순환에 대한 질량 보존의 개념 분석

서정욱,김형범,Patrice Potvin 한국지구과학회 2014 한국지구과학회지 Vol.35 No.3

The purpose of this study was to investigate high school students’ conception of conservation of mass throughthe scenario of carbon emission in terms of carbon cycle. Seventy six high school students of 11th grade wereparticipated in this study. Participants were provided with two scenarios that showed a gradual increase and decrease ofatmospheric CO2 amount from the level recorded in 2013 up to 450 ppm and to 340 ppm by 2110, which is the changesof around 15%. We asked participants to explain the reason after having them draw the emissions trajectory of CO2according to scenario. Most participants thought that carbon emission would continue to increase despite the two scenariosof carbon emission making sense in terms of conservation of mass between emissions and the natural removal of carbondioxide. This implies that participants came to think of pattern matching that carbon emission would continue to increaseas they used correlation graphs of carbon emission: that is, the graphs of the evolution of anthropogenic emissions, ofatmospheric CO2, and of global mean temperature, from the beginning of the Industrial Revolution up to date, all ofwhich are shown in high school earth science textbooks. 이 연구의 목적은 탄소 순환 관련 탄소 배출 시나리오를 통해 고등학교 학생들의 질량 보존의 개념을 확인하는것이다. 이 연구를 위해 총 76명의 고등학교 2학년 학생들이 참여하였다. 연구 참여자들에게 2013년의 대기 중 이산화탄소 값이 2110년까지 ±15%의 변화로 450 ppm와 340 ppm으로 점진적으로 증가 또는 감소되는 두 개의 시나리오를제시하였다. 시나리오에 따라 연구 참여자들에게 이산화탄소의 배출량 궤적을 그리게 한 후, 이를 설명하게 하였다. 그결과는 다음과 같다. 대부분의 연구 참여자들은 탄소 배출 시나리오에 따른 이산화탄소 배출량과 자연적 순수 제거량에대한 질량 보존의 추론보다는 이산화탄소 배출량은 앞으로도 계속해서 증가할 것이라는 결과를 나타내었다. 이는 연구참여자들이 고등학교 지구과학 교과서의 탄소 배출과 관련된 그래프들 즉, 산업혁명 이후 최근까지의 인위적 이산화탄소 배출량 그래프, 대기 중 이산화탄소 농도 그래프, 평균 지구의 온도에 대한 그래프를 통해 이산화탄소 배출량이 계속해서 증가할 것이라는 패턴 매칭(pattern matching)을 생각하게 되었다는 것을 의미한다.

How to Maximize the Effectiveness of Prompts in Assistive Technologies According to the Particular Cognitive Profile of People with Alzheimer’s Disease?

Jessica Lapointe,Julie Bouchard,Alexandra Verreault,Audrey Potvin,Bruno Bouchard,Abdenour Bouzouane 보안공학연구지원센터 2013 International Journal of Smart Home Vol.7 No.5

Ansanella granifera gen. et sp. nov. (Dinophyceae), a new dinoflagellate from the coastal waters of Korea

Jeong, Hae Jin,Jang, Se Hyeon,Moestrup, Ojvind,Kang, Nam Seon,Lee, Sung Yeon,Potvin, Eric,Noh, Jae Hoon The Korean Society of Phycology 2014 ALGAE Vol.29 No.2

A small dinoflagellate, Ansanella granifera gen. et sp. nov., was isolated from estuarine and marine waters, and examined by light microscopy, scanning electron microscopy, and transmission electron microscopy. In addition, the identity of the sequences (3,663-bp product) of the small subunit (SSU), internal transcribed spacer (ITS) region (ITS1, 5.8S, ITS2), and D1-D3 large subunit (LSU) rDNA were determined. This newly isolated, thin-walled dinoflagellate has a type E eyespot and a single elongated apical vesicle, and it is closely related to species belonging to the family Suessiaceae. A. granifera has 10-14 horizontal rows of amphiesmal vesicles, comparable to Biecheleria spp. and Biecheleriopsis adriatica, but greater in number than in other species of the family Suessiaceae. Unlike Biecheleria spp. and B. adriatica, A. granifera has grana-like thylakoids. Further, A. granifera lacks a nuclear fibrous connective, which is present in B. adriatica. B. adriatica and A. granifera also show a morphological difference in the shape of the margin of the cingulum. In A. granifera, the cingular margin formed a zigzag line, and in B. adriatica a straight line, especially on the dorsal side of the cell. The episome is conical with a round apex, whereas the hyposome is trapezoidal. Cells growing photosynthetically are $10.0-15.0{\mu}m$ long and $8.5-12.4{\mu}m$ wide. The cingulum is descending, the two ends displaced about its own width. Cells of A. granifera contain 5-8 peripheral chloroplasts, stalked pyrenoids, and a pusule system, but lack nuclear envelope chambers, a nuclear fibrous connective, lamellar body, rhizocysts, and a peduncle. The main accessory pigment is peridinin. The SSU, ITS regions, and D1-D3 LSU rDNA sequences differ by 1.2-7.4%, >8.8%, and >2.5%, respectively, from those of the other known genera in the order Suessiales. Moreover, the SSU rDNA sequence differed by 1-2% from that of the three most closely related species, Polarella glacialis, Pelagodinium bei, and Protodinium simplex. In addition, the ITS1-5.8S-ITS2 rDNA sequence differed by 16-19% from that of the three most closely related species, Gymnodinium corii, Pr. simplex, and Pel. bei, and the LSU rDNA sequence differed by 3-4% from that of the three most closely related species, Protodinium sp. CCMP419, B. adriatica, and Gymnodinium sp. CCMP425. A. granifera had a 51-base pair fragment in domain D2 of the large subunit of ribosomal DNA, which is absent in the genus Biecheleria. In the phylogenetic tree based on the SSU and LSU sequences, A. granifera is located in the large clade of the family Suessiaceae, but it forms an independent clade.

Mixotrophy in the newly described dinoflagellate Ansanella granifera: feeding mechanism, prey species, and effect of prey concentration

Lee, Sook Kyung,Jeong, Hae Jin,Jang, Se Hyeon,Lee, Kyung Ha,Kang, Nam Seon,Lee, Moo Joon,Potvin, Eric The Korean Society of Phycology 2014 ALGAE Vol.29 No.2

Mixotrophic protists play diverse roles in marine food webs as predators and prey. Thus, exploring mixotrophy in phototrophic protists has emerged as a critical step in understanding marine food webs and cycling of materials in marine ecosystem. To investigate the feeding of newly described mixotrophic dinoflagellate Ansanella granifera, we explored the feeding mechanism and the different types of species that A. granifera was able to feed on. In addition, we measured the growth and ingestion rates of A. granifera feeding on the prasinophyte Pyramimonas sp., the only algal prey, as a function of prey concentration. A. granifera was able to feed on heterotrophic bacteria and the cyanobacterium Synechococcus sp. However, among the 12 species of algal prey offered, A. granifera ingested only Pyramimonas sp. A. granifera ingested the algal prey cell by engulfment. With increasing mean prey concentration, the growth rate of A. granifera feeding on Pyramimonas sp. increased rapidly, but became saturated at a concentration of $434ngCmL^{-1}$ (10,845 cells $mL^{-1}$). The maximum specific growth rate (i.e., mixotrophic growth) of A. granifera feeding on Pyramimonas sp. was $1.426d^{-1}$, at $20^{\circ}C$ under a 14 : 10 h light-dark cycle of $20{\mu}Em^{-2}s^{-1}$, while the growth rate (i.e., phototrophic growth) under similar light conditions without added prey was $0.391d^{-1}$. With increasing mean prey concentration, the ingestion rate of A. granifera feeding on Pyramimonas sp. increased rapidly, but slightly at the concentrations ${\geq}306ngCmL^{-1}$ (7,649 cells $mL^{-1}$). The maximum ingestion rate of A. granifera feeding on Pyramimonas sp. was 0.97 ng C $predator^{-1}d^{-1}$ (24.3 cells $grazer^{-1}d^{-1}$). The calculated grazing coefficients for A. granifera feeding on co-occurring Pyramimonas sp. were up to $2.78d^{-1}$. The results of the present study suggest that A. granifera can sometimes have a considerable grazing impact on the population of Pyramimonas spp.

Effects of light intensity, temperature, and salinity on the growth and ingestion rates of the red-tide mixotrophic dinoflagellate <i>Paragymnodinium shiwhaense</i>

Jeong, Hae Jin,Lee, Kyung Ha,Yoo, Yeong Du,Kang, Nam Seon,Song, Jae Yoon,Kim, Tae Hoon,Seong, Kyeong Ah,Kim, Jae Seong,Potvin, Eric Elsevier 2018 HARMFUL ALGAE Vol.80 No.-

<P><B>Abstract</B></P> <P>Among mixotrophic dinoflagellates, the maximum mixotrophic growth rate of the red-tide dinoflagellate <I>Paragymnodinium shiwhaense</I> is relatively high, whereas mortality due to predation is low. To investigate the effects of major environmental parameters on <I>P. shiwhaense</I>, growth and ingestion rates of one strain of <I>P. shiwhaense</I> on the algal prey species <I>Amphidinium carterae</I> (also a dinoflagellate) were determined under various light intensities (0–500 μE m<SUP>−2</SUP>s<SUP>-1</SUP>), water temperatures (5–30 °C), and salinities (5–40). Cells of <I>P. shiwhaense</I> did not grow well in darkness but grew well at light intensities ≥ 10 μE m<SUP>−2</SUP>s<SUP>-1</SUP>. There were no significant differences in either growth or ingestion rates of <I>P. shiwhaense</I> fed <I>A. carterae</I> at light intensities between 10 and 500 μE m<SUP>−2</SUP>s<SUP>-1</SUP>. Furthermore, <I>P. shiwhaense</I> did not grow at 5 °C or ≥ 28 °C. Its growth rates between 7 and 26 °C were significantly affected by temperature, and the optimal temperature for maximal growth was 25 °C. With increasing salinity from 5 to 20, the growth rate of <I>P. shiwhaense</I> fed <I>A. carterae</I> increased and became saturated at salinities between 20 and 40, while the ingestion rate at salinities between 10 and 40 did not significantly change. Thus, overall, the growth and ingestion rates of <I>P. shiwhaense</I> fed <I>A. carterae</I> were affected by temperature and salinity, but not by light intensity other than darkness. These findings provide a beginning basis for understanding the ecology of this potentially harmful algal species in marine coastal ecosystems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effects of environmental factors were assessed on <I>Paragymnodinium shiwhaense</I> growth. </LI> <LI> This mixotroph did not grow in the dark but grew at light intensity >10 μE m<SUP>−2</SUP>s<SUP>-1</SUP>. </LI> <LI> Its growth and ingestion rates were strongly affected by temperature 5 °C or >28 °C. </LI> <LI> Growth rates increased from salinity 5–20, and remained saturated up to salinity 40. </LI> <LI> This study provides a beginning basis for understanding the ecology of <I>P. shiwhaense</I>. </LI> </UL> </P>

Effects of warming and eutrophication on coastal phytoplankton production

Lee, Kyung Ha,Jeong, Hae Jin,Lee, Kitack,Franks, Peter J.S.,Seong, Kyeong Ah,Lee, Sung Yeon,Lee, Moo Joon,Hyeon Jang, Se,Potvin, Eric,Suk Lim, An,Yoon, Eun Young,Yoo, Yeong Du,Kang, Nam Seon,Kim, Kwan Elsevier Science B.V., Amsterdam. 2019 HARMFUL ALGAE Vol.81 No.-

<P><B>Abstract</B></P> <P>Phytoplankton production in coastal waters influences seafood production and human health and can lead to harmful algal blooms. Water temperature and eutrophication are critical factors affecting phytoplankton production, although the combined effects of warming and nutrient changes on phytoplankton production in coastal waters are not well understood. To address this, phytoplankton production changes in natural waters were investigated using samples collected over eight months, and under 64 different initial conditions, established by combining four different water temperatures (i.e., ambient T, +2, +4, and + 6 °C), and two different nutrient conditions (i.e., non-enriched and enriched). Under the non-enriched conditions, the effect of warming on phytoplankton production was significantly positive in some months, significantly negative in others, or had no effect. However, under enriched conditions, warming affected phytoplankton production positively in all months except one, when the salinity was as low as 6.5. These results suggest that nutrient conditions can alter the effects of warming on phytoplankton production. Of several parameters, the ratio of initial nitrate concentration to chlorophyll <I>a</I> concentration [NCCA, μM (μg L<SUP>−1</SUP>)<SUP>−1</SUP>] was one of the most critical factors determining the directionality of the warming effects. In laboratory experiments, when NCCA in the ambient or nutrient-enriched waters was ≥1.2, warming increased or did not change phytoplankton production with one exception; however, when NCCA was <1.2, warming did not change or decreased production. In the time series data obtained from the coastal waters of four target countries, when NCCA was 1.5 or more, warming increased phytoplankton production, whereas when NCCA was lower than 1.5, warming lowered phytoplankton production, Thus, it is suggested that NCCA could be used as an index for predicting future phytoplankton production changes in coastal waters.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Four temperatures and two nutrient conditions in 8 months were combined. </LI> <LI> Under non-enriched conditions, warming affected positively, negatively, or negligibly. </LI> <LI> Under the enriched conditions, warming in all months except one affected positively. </LI> <LI> Thus, nutrient conditions can alter warming effects on phytoplankton production. </LI> <LI> Ratio of initial nitrate to chlorophyll-a concentration was a critical factor. </LI> </UL> </P>