Seasonal Water-Column Structure Drives the Trophic Niche of Fish Communities on a Temperate Continental Shelf.

In seasonally stratified marine environments, the dynamics of benthic-pelagic coupling plays a crucial role in shaping food web structures and fisheries production. We examined fish food web structures across three distinct shelf areas in the Southern Sea of Korea (SSK) during both stratified (summer) and mixed (spring) water conditions using stable isotopes of carbon (δC) and nitrogen (δN). In spring, fish communities exhibited a broader range of δC values compared with summer, indicating more diverse feeding strategies.

Improvement of succinate production from methane by combining rational engineering and laboratory evolution in Methylomonas sp. DH-1.

Recently, methane has been considered a next-generation carbon feedstock due to its abundance and it is main component of shale gas and biogas. Methylomonas sp. DH-1 has been evaluated as a promising industrial bio-catalyst candidate.

Monsoonal impacts on the community trophic niches in two temperate headwater tributaries across a land use continuum.

Pulsed flows following heavy monsoon rain events alter riverine food webs, but their impact on headwater stream food webs across the continuum from forested canopy to open agricultural land use remains unclear. We investigated carbon and nitrogen stable isotopes in macroinvertebrates and fish in two tributaries of the Suyeung River, Korea, before and after heavy monsoon rains to assess changes in community trophic niches. Basal resources (leaf litter and biofilms) exhibited consistent δC and δN values across seasons, with biofilms showing higher δC values.

Trophic niche overlap in coralline algae- and coral-dominated rocky-bottom subtidal communities.

We investigated trophic structures in rocky subtidal ecosystems transitioning from canopy-forming to barren states across coastlines with varying oceanographic conditions. We examined stable isotopes and functional traits of common invertebrate and fish taxa to understand the food-web consequences. We hypothesized that resource exploitation patterns of functional guilds would result in distinct isotopic niches, defining trophic diversity and niche.

Microbial upcycling of methane to phytoene using metabolically engineered Methylocystis sp. MJC1 strain.

Methane, a potent greenhouse gas, requires sustainable mitigation strategies. Here, the microbial upcycling of methane to phytoene, a valuable colorless carotenoid with applications in the cosmeceutical industry was demonstrated. To achieve this goal, a stepwise metabolic engineering approach was employed in Methylocystis sp.

Spatial-temporal impacts of invasive Spartina anglica on the rates and pathways of organic carbon mineralization and resulting C-Fe-S cycles in the intertidal wetland of the Han River Estuary, Yellow Sea.

To elucidate the spatial-temporal impact of invasive saltmarsh plant Spartina anglica on the biogeochemical processes in coastal wetlands, we investigated the rates and partitioning of organic carbon (C) mineralization in three representative benthic habitats: (1) vegetated sediments inhabited by invasive S. anglica (SA); vegetated sediments by indigenous Suaeda japonica; and (3) unvegetated mud flats. Microbial metabolic rates were greatly stimulated at the SA site during the active growing seasons of Spartina, indicating that a substantial amount of organic substrates was supplied from the high below-ground biomass of Spartina.

Spatiotemporal variation of sterols in sediment as markers of primary production and ocean sewage dumping in the southwestern East Sea (Japan Sea).

The sedimentation of organic carbon in the Ulleung Basin, in the southwestern East Sea (Japan Sea) was investigated using radiocarbon and sterols. The accumulation rates of organic carbon and the contents of brassicasterol and dinosterol were higher on the slope than in the central basin, reflecting the surface water productivity, whereas cholesterol showed similar or higher contents in the central basin. The coprostanol concentration in surface sediments reflected the dispersion of sewage dumped in this region.

Trophic assessment of red seabream (Pagrus major) as a possible bioindicator of human activities in the South Sea of Korea using stable C and N isotopes.

To assess the impact of sand mining on resource utilization by the red seabream (Pagrus major) and the trophic structure of fish assemblages two years after mining activities, we compared stable isotope ratios (δC and δN) and isotopic niches between aggregated mining and control sites in April and August 2022. Our results showed no spatial differences in the δC and δN values of red seabream between the sand mining and control sites, suggesting that the mining did not affect their dietary resources. Furthermore, the considerable overlap among fish consumers suggested that the fish food web in mining areas has trophic functions similar to those in natural habitats after mining activities.

Fibrinous pleuritis associated with in a leopard cat ().

Leopard cat () is a small wild cat assessed as an endangered wildlife in Korea. There have been very few reports of their diseases. Herein, we describe fibrinous pleuritis caused by infection with excessive pleural effusion, hydropericardium, mild ascites, and liver fibrosis in a leopard cat.

Effects of microfiber and bead microplastic exposure in the goldfish Carassius auratus: Bioaccumulation, antioxidant responses, and cell damage.

We confirmed antioxidant-related gene expression, bioaccumulation, and cell damage following exposure to various microplastics in vivo and in vitro in the goldfish Carassius auratus. Exposure of C. auratus to a 500 µm fiber-type microplastic environment (MF; 10 and 100 fibers/L) and two sizes (0.

Micro-polystyrene plastic and benzo[α]pyrene exposure affects the endocrine system and causes physiological stress in Carassius auratus.

Microplastics, owing to their hydrophobic properties and the various chemicals used in their production, can act as carriers of persistent organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs). In this study, we exposed the goldfish Carassius auratus to benzo[α]pyrene (BaP, 10 μg/L), a representative PAH, and micro-polystyrene plastic (MP; 10 and 100 beads/L), of size 1.0 μm, as a single or complex environmental stressor, and evaluated the stress response and the resulting DNA damage.

Coupling and decoupling of marine stramenopiles and cyanobacteria in eutrophic coastal waters of Korea.

The spatiotemporal distribution of MASTs (MArine STramenopiles), mostly affiliated with heterotrophic protists, and their interactions with Synechococcales were investigated in an anthropogenically polluted bay of the East Sea using 18S rRNA and 16S rRNA gene sequences. The bay was characterized by strong stratification between the surface and bottom layers and cold and nutrient-rich water intrusion in summer, whereas the bay water was well mixed in winter. MAST-3, MAST-6, MAST-7, and MAST-9 were the major MAST clades, whereas the dominance of MAST-9 declined from >80 % in summer to <10 % in winter and the diversity of MAST communities increased in winter.

Estuarine dam water discharge enhances summertime primary productivity near the southwestern Korean coast.

The gate opening of estuarine dams discharge a large amount of freshwater into coastal zones during the summer monsoon in northeast Asia. We investigated seasonal and spatial variations in primary productivity (PP) and community structures of phytoplankton on a downstream macrotidal flat and examined the dam discharge effects. Our harmonic analysis of the PP revealed a clear seasonality with a unimodal peak in summer, possibly driven by high ammonium loading through internal recycling.

Machine learning-guided prediction of potential engineering targets for microbial production of lycopene.

The process of designing streamlined workflows for developing microbial strains using classical methods from vast amounts of biological big data has reached its limits. With the continuous increase in the amount of biological big data, data-driven machine learning approaches are being used to overcome the limits of classical approaches for strain development. Here, machine learning-guided engineering of Deinococcus radiodurans R1 for high-yield production of lycopene was demonstrated.

Phylogenetic diversity and spatiotemporal dynamics of bacterial and microeukaryotic plankton communities in Gwangyang Bay of the Korean Peninsula.

Nutrient dynamics function globally, flowing from rivers to the ocean (estuarine-coastal zone), and are vulnerable to climate change. Microbial habitats can be affected by marine nutrient dynamics and may provide a clue to predict microbial responses to environmental heterogeneity in estuarine-coastal zones. We surveyed surface seawater in Gwangyang Bay, a semi-enclosed estuary in Korea, from 2016 to 2018 using a metabarcoding approach with prokaryotic 16S and eukaryotic 18S rRNA genes.

Variability in blue carbon storage related to biogeochemical factors in seagrass meadows off the coast of the Korean peninsula.

Coastal vegetated habitats such as mangroves, salt marshes, and seagrasses, referred to as blue carbon ecosystems, play an important role in climate change mitigation by an effective CO capture from atmosphere and water columns and long-term organic carbon (C) storage in sediments. Although seagrass meadows are considered intense carbon sinks, information on regional variability in seagrass blue carbon stock and factors influencing its capacity still remain sparse. In the present study, seagrass blue carbon storage by measuring C stocks in sediments and living seagrass biomass, and carbon accumulation rates (CARs) in seagrass meadows were estimated along the Korean coast.

Trophic Enrichment Factors of Carbon and Nitrogen Isotopic Ratios (ΔC and ΔN) in Four Marine Ciliates.

Understanding the magnitude and causes of isotopic fractionation between organisms and their dietary resources is crucial for gaining knowledge on stable isotope ecology. However, little is known regarding the diet-tissue fractionation values of marine ciliates, which play a critical role in the reconstruction of microbial food webs. In the present study, we conducted experiments on two benthic ( and ) and two pelagic ( and ) marine ciliates, where they were fed with isotopically constant foods ( and ) under laboratory culture conditions to determine their carbon and nitrogen isotopic fractionation values (ΔC and ΔN).

Immune-metabolic receptor GPR84 surrogate and endogenous agonists, 6-OAU and lauric acid, alter Brucella abortus 544 infection in both in vitro and in vivo systems.

Brucella abortus, one of the most important members of the genus Brucella responsible for human disease, is an intracellular pathogen capable of avoiding or interfering components of the host immune responses that are critical for its virulence. GPR84, on the other hand, is a seven-transmembrane GPCR involved in the inflammatory response and its induced expression was associated with B. abortus infection of RAW264.

Trophic structures of artificial reef communities off the southern coast of the Korean peninsula as determined using stable isotope analyses.

The deployment of artificial reefs (ARs) has become a popular technique for creating new hard-bottom habitats, and for enhancing biodiversity and resource abundance for fisheries. We compared colonizing faunal assemblages and reef-associated food-web structures between ARs and nearby natural reefs (NRs) off the Korean coast using stable isotope techniques. Reef communities showed high compositional disparities in colonizing assemblages.

Formyl peptide receptor 2 (FPR2) antagonism is a potential target for the prevention of Brucella abortus 544 infection.

Here, we explore the potential role of formyl peptide receptor 2 (FPR2) during Brucella abortus infection. FPR2 manipulation affected B. abortus internalization but not its growth within macrophages.

Characteristics of Different Size Phytoplankton for Primary Production and Biochemical Compositions in the Western East/Japan Sea.

The current phytoplankton community structure is expected to change, with small phytoplankton becoming dominant under ongoing warming conditions. To understand and evaluate the ecological roles of small phytoplankton in terms of food quantity and quality, the carbon uptake rates and intracellular biochemical compositions (i.e.

Shifting resource utilization of the lacustrine shrimp Palaemon paucidens in temperate coastal lagoons of Korea as revealed by stable isotopes.

The spatial and seasonal variations in resource use of the lacustrine shrimp Palaemon paucidens were investigated in three different Korean lagoon systems in June and October 2018 by measuring their carbon and nitrogen stable isotope ratios. P. paucidens had much higher δC values at the permanently open lagoon (PL) as compared to the intermittently open lagoons (ILs), revealing a disparity in resource utilization.