Se-Jong Ju

Korean Institute of Ocean Science and Technology | KIOST · Deep-sea and Seabed Resources Research Division

Abyssal seafloor communities cover more than 60% of Earth’s surface. Despite their great size, abyssal plains extend across modest environmental gradients compared to other marine ecosystems. However, little is known about the patterns and processes regulating biodiversity or potentially delimiting biogeographical boundaries at regional scales in t...

Energy sources and trophic interactions among vent fauna were investigated in deep-sea hydrothermal vents in the North Fiji Basin (NFB), Southwest Pacific, using stable sulfur, carbon, and nitrogen isotopes. A Bayesian isotope mixing model (MixSIAR) was used to quantify the proportions of energy sources for symbiont-bearing taxa. Based on these res...

A comprehensive understanding of the deep-sea environment and mining’s likely impacts is necessary to assess whether and under what conditions deep-seabed mining operations comply with the International Seabed Authority’s obligations to prevent ‘serious harm’ and ensure the ‘effective protection of the marine environment from harmful effects’ in ac...

Imbricaverruca and Neoverruca are two genera of hydrothermal vent asymmetrical barnacles in Neoverrucidae, but found in vents of the Southwest Pacific and Northwest Pacific Oceans, respectively. Imbricaverruca has a flattened operculum and the shell base with multiple whorls of imbricating plates, while Neoverruca has an inclined operculum and the...

We examined the biogenic and lithogenic particle composition and radiocarbon content of sinking particulate organic carbon to investigate sediment resuspension and its contribution to sinking particles on the deep abyssal plain of the Eastern Tropical Pacific Ocean. Samples were collected using sediment traps from August 2011 to July 2012 at depths...

Host–symbiont relationships in hydrothermal vent ecosystems, supported by chemoautotrophic bacteria as primary producers, have been extensively studied. However, the process by which densely populated co‐occurring invertebrate hosts form symbiotic relationships with bacterial symbionts remains unclear. Here, we analyzed gill‐associated symbiotic ba...

Balanomorph Eochionelasmus species are hydrothermal vent endemic barnacles. In the genus Eochionelasmus, three species are known to date and they distribute at three different vent fields in Pacific and Indian Oceans, E. ohtai in the Southwest Pacific Ocean, E. paquensis in the East Pacific Ocean, and E. coreana in the Indian Ocean. Therefore, Eoch...

The workshop aimed to identify coherent, collaborative, and scientifically robust solutions to addressing taxonomic knowledge gaps in various stages from collection, preservation and archiving of biological samples and taxonomic data to identification and description of species. Specifically, the workshop focused on: (i) identifying specific needs...

A new species of chionelasmatid sessile vent barnacle, Eochionelasmus coreana sp. nov., is described and illustrated on the basis of specimens collected from the Solitaire hydrothermal vent field in the Central Indian Ridge of the Indian Ocean. This new species is morphologically very similar to E. ohtai , the type species of the genus Eochionelasm...

The family Provannidae is endemic to chemosynthetic environments in the deep-sea. Here, we report the complete mitogenome of a provannid vent snail Alviniconcha boucheti from the North Fiji Basin for the first time. The length of mitogenome was 15,981 bp, with 67.7% AT content. The mitogenome content and its protein-coding gene organization resembl...

Isaacsicalanus paucisetus Fleminger, 1983, a monotypic species of the family Spinocalanidae Vervoort, 1951, was first reported from a hydrothermal vent field in the East Pacific Rise off the mouth of the Gulf of California. The mitochondrial cytochrome oxidase I (mtCOI) DNA barcodes are considered a useful tool to assist traditional taxonomy and sp...

Since deep-sea hydrothermal vents have been targeted for mining mineral resources, concerns about the potential impacts of mining on vent ecosystems have gradually increased. The vent alvinocaridid shrimp is one of the dominant endemic vent organisms. We collected an experimental species, Nautilocaris saintlaurentae, from the Tonga Arc in the South...

The family Eolepadidae is the only stalked barnacle in hydrothermal vent regions. Here, we determined the mitogenome of the eolepadid Vulcanolepas fijiensis. The mitogenome was 17,374 bp long, with 76.6% AT content. Its protein-coding gene organization was identical to that of the deep-sea scalpellid Arcoscalpellum epeeum. On the mitogenomic tree,...

The family Alvinocarididae is the monophyletic taxon which lives restrictively at chemosynthesis-based environments in the deep-sea. Here, for the first time, we report the complete mitogenome of the alvinocaridid vent shrimp Rimicaris variabilis from the North Fiji Basin. The mitogenome was 15,909 bp in length, with 65.6% AT content. Its protein-c...

To understand the origin, migration, and distribution of organisms across disjunct deep-sea vent habitats, previous studies have documented the population genetic structures of widely distributed fauna, such as gastropods, bivalves, barnacles, and squat lobsters. However, a limited number of investigations has been conducted in the Southwest Pacifi...

Information about A. alayseae specimens used in this study. Classification, sampling locations, sample IDs, and DNA sample IDs of the species and GenBank accession numbers of genetic sequences used in this study. (XLSX)

Information about Bythograeidae specimens used for phylogenetic analysis. Classification and sampling locations of the species and GenBank accession numbers of genetic sequences used. (XLSX)

Information about Bythograeidae specimens used for distance calculation. Classification and sampling locations of the species and GenBank accession numbers of the COI gene sequences used. (XLSX)

Understanding the fate of terrestrial plant waxes from source to sink is critical for improving paleoclimate interpretations from sedimentary plant waxes. However, there is limited knowledge about the controls on plant wax integration and transport in large catchments with multiple biomes and climates. To address this lack of understanding, we inve...

A new species of eolepadid stalked barnacle, Vulcanolepas fijiensis sp. nov., was collected from a hydrothermal vent in the North Fiji Basin, Southwestern Pacific Ocean, at a depth of 1988 m. Based on morphological characteristics, this new species was distinguished from its relatives, V. osheai Buckeridge, 2000, V. parensis Southward, 2005, V. sco...

Non-monophyletic Poecilasmatids are deep-water epibiotic barnacles and are classified as five-capitular-plate members of the Lepadiformes. Here, we offer the first characterization of the mitogenome of a Poecilasmatid barnacle (Glyptelasma annandalei). The mitogenome was 16,107 bp long, with 72.3% AT content. Its gene arrangement was identical to t...

We investigated seasonal variations in the abundance of the adults and the resting eggs of copepods to understand the role of copepod resting eggs for maintaining their population inhabiting the coastal area of Dadaepo, Korea. Adults and resting eggs of copepods were collected bimonthly with a conical net (45 cm mouth diameter, 330 µm mesh size) an...

Euphausia pacifica (E. pacifica) is an important food source for fish and other organisms in marine ecosystems. We analyzed the carbon- and nitrogen-stable isotope ratios in potential diet sources to determine the feeding characteristics of E. pacifica in the Yellow Sea Cold Water Mass (YSCWM), a habitat for oversummering. E. pacifica was collected...

Thoracican barnacles are common in hydrothermal vent fields. Here, we characterized the first mitogenome of a hydrothermal vent barnacle. The mitogenome of Eochionelasmus ohtai was 15,585 bp in length and had the typical pancrustacean gene arrangement. Its protein-coding genes (PCGs) were very similar in terms of length, AT content, and start and s...

The hitherto suborder Verrucomorpha contains asymmetrical barnacles of two groups: the true Verrucomorpha (Eoverruca + Verrucidae) and the Neoverrucidae. Here, we determined the mitochondrial genome (mitogenome) of Altiverruca navicula, a true Verrucomorpha species. The mitogenome was 15,976 base pairs in length and had the typical pancrustacean ge...

The spatial distributions of δ13C, δ15N, and n-alkanes were investigated to determine the source and transportation of allochthonous organic matter from the mouth of the Seomjin River to the southern inner shelf break of Korea. Total organic carbon (%) ranged from 0.3% to 1.6% (average = 0.80%, n = 81), and the C/N ratio varied from 2.4 to 12.4 (av...

This study reports the first finding of tropical blacklip pearl (BLP) oyster, Pinctada margaritifera, in Korean waters. One BLP oyster was found and sampled from Beom-seom islet (33°13'N, 126°33'E) in the southern coast of Jeju Island, Korea in February, 2011. The taxonomic status of the specimen was confirmed by nucleotide sequences of the mitocho...

The effect of iron (Fe) fertilization on biological productivity and community structure in the equatorial Pacific, a region with high nutrient and low chlorophyll concentrations, has been debated for many years. Here we present lipid biomarker and geochemical proxy records in a sediment core from the central equatorial Pacific spanning from 1100 t...

Although the response unit of living organisms to environmental changes is at the individual level, most experiments on the adaptation responses of ciliates have been conducted in batches, comprising multiple-individuals, due to their microscopic size. However, here, we confirmed that individuals undergo different division cycles in monocultures of...

A new species of callianassid ghost shrimp, Paraglypturus tonganus sp. nov., is described and illustrated on the basis of five specimens that were collected from sediments in a vent field of the Tonga Arc, south western Pacific Ocean. This new species is morphologically very similar to P. calderus Türkay & Sakai, 1995, the type species of the genus...

Studies of sinking particles associated with hydrothermal vent fluids may help us to quantify mass transformation processes between hydrothermal vent plumes and deposits. Such studies may also help us understand how various types of hydrothermal systems influence particle flux and composition. However, the nature of particle precipitation out of hy...

Zooplankton plays a key role in marine ecosystems as an energy link between primary producers and higher trophic levels in the pelagic food web. In the East Sea (Japan Sea), some studies of zooplankton in terms of their species and distribution have been conducted in selected regions, but there is a lack of reviews and/or summaries of zooplankton s...

To track the diet of minke whale (Balaenoptera acutorostrata) in the East Sea (Japan Sea), a conjoint analysis of fatty acids and C and N stable isotopes was performed on blubber and skin from the whale and its potential prey. The total lipid content in the blubber of minke whales ranged from 37.9% to 82.7% of wet mass (mean ± SD, 63.1 ± 17.2%), wi...

Little is known regarding how harmful algal bloom species respond to different temperatures in terms of fatty acid production. This study examined the effects of temperature on the growth rates, cell volumes, and fatty acid concentrations and compositions of four harmful algal bloom species (HABs), Akashiwo sanguinea, Alexandrium tamarense, Chatton...

To understand the diet of chaetognaths, the gut content and fatty acid trophic makers (FATMs) of Sagitta crassa and S. nagae, which are the most predominant species of chaetognath in the Yellow Sea, were analyzed. Gut contents of the two species examined by microscopic analysis revealed that copepods are the major components of the diet (> 70% of g...

Abstract Ghost shrimps are burrowing decapods that serve as bioturbators and habitat providers in seafloor environments. The hydrothermal vent ghost shrimp, Paraglypturus tonganus, was collected from a hydrothermal vent in the Tonga Arc. This species has a mitochondrial genome (mitogenome) of 15,924 bp in length with an AT content of 66.1%. The mit...

Corals reefs and communities support a wide range of flora and fauna. The complete richness and abundance of faunal communities in either coral reefs or communities is not fully understood. This is especially true for high-latitude coral communities. In this work, we carried out an analysis of Alveopora japonica, which is associated mollusk assembl...

Corals reefs and communities support a wide range of flora and fauna. The complete richness and abundance of faunal communities in either coral reefs or communities is not fully understood. This is especially true for high-latitude coral communities. In this work, we carried out an analysis of an Alveopora japonica associated mollusk assemblage, in...

The mid-Pleistocene climate transition (MPT), is a complex climatic change which brought about the Late Pleistocene ice age around 0.9Ma and shift in the dominant periodicity of glacial-interglacial oscillations from 41 to 100kyr. The MPT marks a change in the climate system in response to external forcing, bringing about changes in the deep water...

The brachyuran crab Gandalfus puia is a species endemic to the hydrothermal vent fields in the Tonga-Kermadec Arc. In order to understand G. puia at the genomic level, we sequenced its mitochondrial genome (mitogenome) and then compared to other bythograeids. The mitogenome is 15,548 bp in length and exhibits brachyuran-typical gene arrangement. It...

Microalgae hold promise as producers of sustainable biomass for the production of biofuels and other biomaterials. However, selection of strains with efficient and robust production of desirable resources remains challenging. In this study, we isolated a green microalga from Korea and analyzed its morphological, molecular and biochemical characteri...

Although coral reefs are facing severe challenges from a variety of natural and anthropogenic stresses, there is anecdotal evidence that the high-latitude coral species Alveopora japonica Eguchi, 1968, has increased its population over the past two decades around Jeju Island, off the southern coast of Korea. The present study provides the first eco...

Verifying the similarity of environmental characteristics between an artificial impact site and a preserved or reference site is necessary to quantitatively and qualitatively evaluate the environmental impact of mining activity. Although an impact site (BIS station) and a preserved site (called KOMO station) that have been selected in the Korea man...

A unicellular red microalga was isolated from environmental freshwater in Korea, and its morphological, molecular and biochemical properties were characterized, respectively. Morphological analysis revealed that the isolate was biflagellated unicellular green microalga with forming a non-motile, thick-walled palmelloid or red aplanospore. To determ...

At an international symposium on the marine systems of the Pacific region of East Asia, scientists concluded that changes in the ocean environment are having a significant effect on biogeochemical cycles and ecosystems and, consequently, on humans and the food supply. The meeting, the 6th China-Japan-Korea (CJK) Integrated Marine Biogeochemistry an...

Carbon cycling and productivity within Weno Island of Micronesia enclosed by the coral reef may be likely self-maintained and insignificantly affected by the open ocean. Therefore, it is important to understand the role of the mangrove known as providing the organic matter and habitats for many organisms in this enclosed area. In order to trace the...

We investigated gonad development and reproductive effort (RE) of the Manila clam Ruditapes philippinarum at Jeju Island, Korea. Gonad maturation and RE were determined using histology and an indirect enzyme-linked immunosorbent assay (ELISA). In June 2006, most of the clams (80%) in the lagoon were in the resting stage. Spawning clams first appear...

Abstract We determined the mitochondrial genome (mitogenome) of Nautilocaris saintlaurentae, sampled at vent fields of the Tofua Arc in the southwestern Pacific. The genome was 15,928 bp in length and had the typical mitogenome structure of the infraorder Caridea. Its protein-coding genes were very similar to other alvinocaridid species in respect...

Euphausia pacifica occupy a remarkably wide range of ecosystems. We examined the differences in brood sizes from eight regions of the North Pacific to explore how variation in the brood size might contribute to their success over such a range. We show a compilation and analysis of short-term E. pacifica brood size incubations from around the North...

According to the Intergovernmental Panel on Climate Change (IPCC), ocean warming and acidification are accelerating as a result of the continuous increase in atmospheric . This may affect the function and structure of marine ecosystems. Recently, changes in marine environments/ecosystems have been observed (increase in SST, decrease in the pH of se...

Abstract The brachyuran crab Austinograea alayseae is one of the most common species found in hydrothermal vent fields of the southwestern Pacific Ocean. In this study, we found that the mitochondrial genome (mitogenome) of A. alayseae from Tofua Arc is 15,611 bp in length and has the typical gene arrangement of a brachyuran. We also compared the m...

Members of the brachyuran crab family, Bythograeidae, are among the most abundant and common crabs in vent fields. However, their identification based on morphological characteristics often leads to incorrect species recognition due to a lack of taxonomic factors and the existence of sibling (or cryptic) species. For these reasons, we used DNA barc...

a b s t r a c t Mining seafloor massive sulfides for metals is an emergent industry faced with environmental manage-ment challenges. These revolve largely around limits to our current understanding of biological variability in marine systems, a challenge common to all marine environmental management. VentBase was established as a forum where academ...

a b s t r a c t Mining seafloor massive sulfides for metals is an emergent industry faced with environmental manage-ment challenges. These revolve largely around limits to our current understanding of biological variability in marine systems, a challenge common to all marine environmental management. VentBase was established as a forum where academ...

Mining seafloor massive sulfides for metals is an emergent industry faced with environmental management challenges. These revolve largely around limits to our current understanding of biological variability in marine systems, a challenge common to all marine environmental management. VentBase was established as a forum where academic, commercial, g...

Mining seafloor massive sulfides for metals is an emergent industry faced with environmental management challenges. These revolve largely around limits to our current understanding of biological variability in marine systems, a challenge common to all marine environmental management. VentBase was established as a forum where academic, commercial, g...

Name: Austinograea alayseae TA26A01, cytochrome oxidase subunit I (COI) gene, partial cds; mitochondrial.