Hae Jin Jeong

Hae Jin Jeong
Seoul National University | SNU · Department of Earth and Environmental Sciences

PhD, Scripps Institution of Oceanography-UC San Diego

About

307
Publications
59,889
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8,169
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Introduction
Biological Oceanography, Plankton, Aquatic Microbial Ecology, Red tide, HAB, Dinoflagellate, Diatom, Ciliate, Protist, Microalgae, Cyanobacteria, Marine Biotechnology, Useful materials, genes, and functions of plankton, responses by marine ecosystems to diverse scale environmental changes, Cycling of carbon, nitrogen, and oxygen

Publications

Publications (307)
Article
Full-text available
Microalgae fuel food webs and biogeochemical cycles of key elements in the ocean. What determines microalgal dominance in the ocean is a long-standing question. Red tide distribution data (spanning 1990 to 2019) show that mixotrophic dinoflagellates, capable of photosynthesis and predation together, were responsible for ~40% of the species forming...
Article
Full-text available
We report here for the first time that 5 red-tide dinoflagellates (Gymnodinium catenatum, G. impudicum, Lingulodinium polyedrum, Prorocentrum donghaiense, and P. triestinum) which had been previously thought to be exclusively autotrophic dinoflagellates are mixotrophic species. We investigated the feeding behaviors, the kinds of prey species that 1...
Article
Full-text available
Red tides – discolorations of the sea surface due to dense plankton blooms – occur regularly in coastal and offshore waters along much of the world's coastline. Red tides often cause large-scale mortalities of fish and shellfish and significant losses to the aquaculture and tourist industries of many countries. Therefore, understanding and predicti...
Article
Full-text available
Planktonic mixotrophic and heterotrophic dinoflagellates are ubiquitous protists and often abundant in marine environments. Recently many phototrophic dinoflagellate species have been revealed to be mixotrophic organisms and also it is suggested that most dinoflagellates may be mixotrophic or heterotrophic protists. The mixotrophic and heterotrophi...
Article
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Survival of free-living and symbiotic dinoflagellates (Symbiodinium spp.) in coral reefs is critical to the maintenance of a healthy coral community. Most coral reefs exist in oligotrophic waters, and their survival strategy in such nutrient-depleted waters remains largely unknown. In this study, we found that two strains of Symbiodinium spp. cultu...
Article
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Noctiluca scintillans is a heterotrophic dinoflagellate that causes red-colored oceans during the day (red tides) and glowing oceans at night (bioluminescence). This species feeds on diverse prey, including phytoplankton, heterotrophic protists, and eggs of metazoans. Thus, many scientists have conducted studies on the ecophysiology of this species...
Preprint
The key nutrient sources for red-tide species are freshwater and deep cold waters. However, a lack of data on their growth rates at different depths limits our understanding of the effects of deep cold waters on red-tide formation. Offshore water was collected from 0, 20, and 40 m in the South Sea of Korea and the growth rates of major red-tide spe...
Article
Full-text available
Water temperature affects plankton survival and growth. The dinoflagellate Shimiella gracilenta survives using the plastids of ingested prey, indicating kleptoplastidy. However, studies on the effects of water temperature on kleptoplas-tidic dinoflagellates are lacking. We explored the growth and ingestion rates of S. gracilenta as a function of wa...
Article
Full-text available
To explore the ecophysiological characteristics of the kleptoplastidic dinoflagellate Shimiella gracilenta, we determined its spatiotemporal distribution in Korean coastal waters and growth and ingestion rates as a function of prey concentration. The abundance of S. gracilenta at 28 stations from 2015 to 2018 was measured using quantitative real-ti...
Article
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Some species in the dinoflagellate genus Alexandrium are bioluminescent. Of the 33 formally described Alexandrium species, the bioluminescence capability of only nine species have been tested, and eight have been reported to be bioluminescent. The present study investigated the bioluminescence capability of seven Alexandrium species that had not be...
Article
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Dinoflagellates are a major component of marine ecosystems, and very cold and hot water may affect their survival. Global warming has amplified the magnitude of water temperature fluctuations. To investigate the molecular responses of dinoflagellates to very cold and hot water, we compared the differentially expressed genes of the phototrophic dino...
Article
Full-text available
The newly described dinoflagellate, Shimiella gracilenta, is known to survive for approximately 1 month on the plastids of ingested prey cells during starvation, indicating kleptoplastidy. To understand the population dynamics of this dinoflagellate in marine planktonic food webs, its growth and mortality rate due to predation should be assessed. T...
Conference Paper
The Global Harmful Algal Blooms (GlobalHAB, www.global hab.info) Program is aimed at fostering international cooperative research directed toward improving the prediction of harmful algal bloom (HAB) events in aquatic ecosystems, and providing sound knowledge for policy- and decision-making to manage and mitigate HAB impacts in a changing planet. G...
Article
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Phytoplankton blooms can cause imbalances in marine ecosystems leading to great economic losses in diverse industries. Better understanding and prediction of blooms one week in advance would help to prevent massive losses, especially in areas where aquaculture cages are concentrated. This study has aimed to develop a method to predict the magnitude...
Article
Vitamins are an important growth factor for the majority of microalgae. Although the effects of light and prey availability on the growth and feeding of mixotrophic dinoflagellates are relatively well understood, the effects of vitamins are currently poorly understood. We investigated the effects of vitamin conditions on feeding by the red tide-for...
Article
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The occurrence of benthic dinoflagellates, many of which are known to be toxic, is a critical concern for scientists, government officers, and people in the aquaculture, dining, and tourism industries. The interest in these dinoflagellates in countries with temperate climate is increasing because tropical or subtropical species introduced into temp...
Article
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Marine plankton comprise the largest portion of the marine biomass, and play critical roles in the global carbon cycle. The carbon retention of marine-plankton communities is as important as their primary production; however, data on the annual carbon retention of marine-plankton communities based on daily sample analysis are limited. Using our pub...
Article
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Heterotrophic dinoflagellates Gyrodinium spp. are one of the major grazers of phytoplankton in many coastal waters. Gyrodinium dominans, G. jinhaense, and G. moestrupii have similar morphologies but different edible prey species. To explore the variations in the ecological niches of these three species, we investigated their spatial-temporal distri...
Article
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The mixotrophic dinoflagellate Tripos furca causes red tides in the waters of many countries. To understand its popu-lation dynamics, mortality due to predation as well as growth rate should be assessed. Prior to the present study, the heterotrophic dinoflagellates Noctiluca scintillans, Polykrikos kofoidii, Protoperidinium steinii, and mixotrophic...
Article
Full-text available
Heterotrophic dinoflagellates are major grazers of microalgae in marine food webs. The feeding of the newly-described heterotrophic dinoflagellate Gyrodinium jinhaense was explored by providing 19 common microalgal prey species and the ciliate Mesodinium rubrum as prey. Furthermore, the specific growth and ingestion rates of G. jinhaense feeding on...
Article
Full-text available
Omega-3 fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are polyunsaturated fatty acids beneficial to human health. A limited number of microalgae have been used for commercial omega-3 production, which necessitates the identification of new microalgae with high omega-3 contents. We explored the fatty acid composi...
Article
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Gymnodinium smaydae is a newly described mixotrophic dinoflagellate that feeds on only Heterocapsa spp. and Scrippsiella acuminata among 19 tested algal prey. It is one of the fastest growing dinoflagellates when feeding, but does not grow well without prey. To investigate its spatial-temporal distributions in Korean waters, we quantified its abund...
Article
Full-text available
Water temperature is known to affect the growth and feeding of marine dinoflagellates. Each dinoflagellate species grows well at a certain optimal temperature but dies at very cold and hot temperatures. Thus, changes in water temperatures driven by global warming and extremely high or low temperatures can affect the distribution of dinoflagellates....
Article
Members of the genus Cladocopium are the most ecologically dominant and geographically widespread group of mutualistic dinoflagellates. Formal species descriptions of this newly erected genus should improve scientific investigations and communication about the biology of these important symbionts. Here we combine morphology and genetic evidence wit...
Article
A small dinoflagellate, ~13 um in cell length, was isolated from Jinhae Bay, Korea. Its morphology under a light microscope was similar to that of the kleptoplastidic dinoflagellate Gymnodinium gracilentum, whose genetic characterization and morphology under an electron microscope have not been reported yet. In this study, the rDNA sequences were d...
Article
Full-text available
Gymnodinium smaydae is a fast–growing mixotrophic dinoflagellate. This study investigated whether light intensity (0–346 µmol photons m-2 s-1) and temperature (5–35 oC) affect the autotrophic or mixotrophic growth rate or ingestion rate of Gymnodinium smaydae GSSH1005. At all light intensities tested, G. smaydae GSSH1005 showed negative autotrophic...
Article
A ubiquitous dinoflagellate, Alexandrium, produces paralytic shellfish toxin (PST), and its outbreaks have negative impacts on aquaculture, fisheries, human health, and the marine ecosystem. To minimize such damages, a routine monitoring program of toxic species must be implemented with a suitable analytical technique for their identification and q...
Article
Full-text available
Mixotrophy in marine organisms is an important aspect of ecology and evolution. The discovery of mixotrophic abilities in phototrophic dinoflagellates alters our understanding of the dynamics of red tides. In the phototrophic dino-flagellate genus Alexandrium, some species are mixotrophic, but others are exclusively autotrophic. There are differenc...
Article
Full-text available
The dinoflagellate genus Alexandrium is known to often form harmful algal blooms causing human illness and large-scale mortality of marine organisms. Therefore, the population dynamics of Alexandrium species are of primary concern to scientists and aquaculture farmers. The growth rate of the Alexandrium species is the most important parameter in pr...
Article
Full-text available
Dinoflagellates are often responsible for harmful algal blooms. Many dinoflagellates move quickly to capture prey cells, escape from predation, and conduct diurnal vertical migrations, but they form cysts (non-motile stage) when growth conditions are not favorable. To investigate differences in gene expression between vegetative cells and cysts of...
Article
Takayama helix is a mixotrophic dinoflagellate that can feed on diverse algal prey. We explored the effects of light intensity and water temperature, two important physical factors, on its autotrophic and mixotrophic growth rates when fed on Alexandrium minutum CCMP1888. Both the autotrophic and mixotrophic growth rates and ingestion rates of T. he...
Article
Full-text available
The newly described phototrophic dinoflagellate Alexandrium pohangense, APPH1409, fed only on the dinoflagellate Margalefidinium polykrikoides among 16 potential algal prey species tested. To explore the ecophysiology of A. pohangense, its growth and ingestion rates with and without added M. polykrikoides prey were determined as a function of light...
Article
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The species in the dinoflagellate order Suessiales have 5-24 latitudinal paraplate series and include many fossil and extant species. There have been a few studies on the ecophysiology of the phototrophic species Biecheleriopsis adriatica, and no study on its predators. Thus, we explored the feeding occurrence by common heterotrophic protists on B....
Article
The dinoflagellate genus Scrippsiella is known to cause red tides. Mortality due to predation should be assessed in order to understand the population dynamics of Scrippsiella species. However, predation has been explored only in a few species. In this study, we examined feeding by common heterotrophic dinoflagellates Oxyrrhis marina, Gyrodinium do...
Article
Full-text available
On land, plants make their own food by photosynthesis and animals live by eating. However, in the microscopic world in the oceans, it is not that simple. Many microscopic so-called plants (phytoplankton) can also eat like animals and many microscopic so-called animals (microzooplankton) can also photosynthesize like plants! More amazingly, some of...
Article
Full-text available
The genus Heterocapsa is one of the major dinoflagellate groups, with some of its species having worldwide distributions. However, prior to the present study, the phototrophic species Heterocapsa minima has been reported only from the northeast Atlantic Ocean. Recently, H. minima was found in the Korean waters, and a clonal culture was established....
Article
Four unarmored heterotrophic dinoflagellates were isolated from the coastal waters of southern Korea. The rDNA sequences of four clonal cultures were determined, and the morphology of one of the four strains was examined using light and scanning electron microscopy. The large subunit (LSU) and small subunit (SSU) rDNA sequences of each of the strai...
Article
Aim Most protist plankton are mixotrophic, with potential to engage in photoautotrophy and phagotrophy; however, the ecology of these organisms has been misdiagnosed for over a century. A large proportion of these organisms are constitutive mixotrophs (CMs), with an innate ability to photosynthesize. Here, for the first time, an analysis is present...
Article
A phototrophic dinoflagellate belonging to the genus Scrippsiella was isolated from a water sample collected from Masan Bay, Korea. Using a clonal culture of this dinoflagellate, its morphology was analysed with light, scanning and transmission electron microscopy, and the sequences of SSU, LSU, and ITS rDNA were studied. The dinoflagellate had a p...