Variations in aragonite saturation state and its controlling factors in the South Yellow Sea in spring and autumn.

To assess the progression of ocean acidification in the South Yellow Sea (SYS), the aragonite saturation state (Ω) was determined from dissolved inorganic carbon (DIC) and total alkalinity (TA) in the surface and bottom waters of the SYS in spring and autumn. The Ω exhibited large spatiotemporal variations in the SYS; DIC was a major factor controlling the Ω variations, whereas temperature, salinity, and TA were minor factors. Surface DIC concentrations were mainly influenced by the lateral transport of the DIC-enriched Yellow River waters and DIC-depleted East China Sea Surface Water; bottom DIC concentrations were affected by aerobic remineralization in spring and autumn.

Changes in the characteristics of organic matter associated with hydrodynamics and phytoplankton size structure in the central-eastern Yellow Sea.

The central-eastern Yellow Sea is an important region for transporting organic matter (OM) to the Pacific Ocean, however, there is limited information available regarding the characteristics and sources of OM in this area. The present study investigated the concentrations and stable isotopic compositions of carbon (δC) and nitrogen (δN) for particulate matter and sediment in the central-eastern Yellow Sea during April 2019. The physicochemical properties (i.

Cyanobiont genetic diversity and host specificity of cyanobiont-bearing dinoflagellate Ornithocercus in temperate coastal waters.

Cyanobacteria are ubiquitous in marine environments and play an important role as primary producers. Some cyanobacteria, the so-called cyanobionts (cyanobacterial symbionts), have a symbiotic relationship with unicellular organisms. Among these relationships, in particular, the nature (e.

Heavy metal pollution assessment in coastal sediments and bioaccumulation on seagrass (Enhalus acoroides) of Palau.

Heavy metals in coastal sediments and seagrass (Enhalus acoroides) were studied to assess the pollution level and to understand the bioaccumulation of metals on different organs. The mean of metal concentrations in sediments were in the following order: Cr > Ni > As>Zn > Cu > Co > Pb > Cd > Hg. The results of principal component analysis indicate that Cr, Ni, Cu, Zn, As and Hg are derived from natural sources but Cd and Pb seems to be of anthropogenic sources.

Evolutionary Mechanisms of Long-Term Genome Diversification Associated With Niche Partitioning in Marine Picocyanobacteria.

Marine picocyanobacteria of the genera and are the most abundant photosynthetic organisms on Earth, an ecological success thought to be linked to the differential partitioning of distinct ecotypes into specific ecological niches. However, the underlying processes that governed the diversification of these microorganisms and the appearance of niche-related phenotypic traits are just starting to be elucidated. Here, by comparing 81 genomes, including 34 new , we explored the evolutionary processes that shaped the genomic diversity of picocyanobacteria.

Daily variation in the prokaryotic community during a spring bloom in shelf waters of the East China Sea.

To understand prokaryotic responses during a spring bloom in offshore shelf waters, prokaryotic parameters were measured daily at a station located in the middle of the East China Sea over a six-week period from March 25 to May 19. The site experienced a phytoplankton bloom in late April, triggering changes in prokaryotic abundance and production after a lag of approximately one week. Before the bloom, changes in prokaryotic composition were small.

Draft genome sequence of CL-YJ9 (DSM 18822), isolated from the rhizosphere of the coastal tidal-flat plant .

The genus belongs to the family within the class and was reported in 1997. Currently the genus contains 16 species. CL-YJ9 was isolated from sediment associated with the roots of a plant growing in a tidal flat of Youngjong Island, Korea.

Identification of benthic diatoms isolated from the eastern tidal flats of the Yellow Sea: Comparison between morphological and molecular approaches.

Benthic diatoms isolated from tidal flats in the west coast of Korea were identified through both traditional morphological method and molecular phylogenetic method for methodological comparison. For the molecular phylogenetic analyses, we sequenced the 18S rRNA and the ribulose bisphosphate carboxylase large subunit coding gene, rbcL. Further, the comparative analysis allowed for the assessment of the suitability as a genetic marker for identification of closely related benthic diatom species and as potential barcode gene.

The reduction in the biomass of cyanobacterial N fixer and the biological pump in the Northwestern Pacific Ocean.

The comparison of sediment trap data with physical and biogeochemical variables in the surface water column of the Tropical Northwestern Pacific Ocean (TNWPO) indicated that the magnitude of the springtime biological pump has reduced with time due to a corresponding decrease in the biomass of cyanobacterial N fixer. The decrease in the biomass of N fixer likely resulted from a reduction in phosphate concentrations in response to surface water warming and consequent shoaling of the mixed layer depth during the study period (2009-2014). The same reduction in biological pump was also observed during summer.

Complete mitochondrial genome of biraphid benthic diatom, (Naviculales, Bacillariophyceae).

The complete mitochondrial DNA of biraphid benthic diatom, TA439 was sequenced and characterized. The circular mitogenome contains 67 genes in 48,652 bp (31.1% GC), including 41 protein-coding, 24 transfer RNA (tRNA) and 2 rRNA genes.

High-quality draft genome sequence of Gracilimonas tropica CL-CB462(T) (DSM 19535(T)), isolated from a Synechococcus culture.

Gracilimonas tropica Choi et al. 2009 is a member of order Sphingobacteriales, class Sphingobacteriia. Three species of the genus Gracilimonas have been isolated from marine seawater or a salt mine and showed extremely halotolerant and mesophilic features, although close relatives are extremely halophilic or thermophilic.

Repeat region absent in mitochondrial genome of tube-dwelling diatom Berkeleya fennica (Naviculales, Bacillariophyceae).

The complete mitochondrial DNA of tube-dwelling diatom, Berkeleya fennica was sequenced and characterized. The circular mitogenome contains 63 genes in 35,509 bp (29.7% GC), including 36 protein-coding, 25 tRNA, 2 rRNA genes.

Complete mitochondrial genome of Upogebia yokoyai (Decapoda, Crustacea) from Jejudo, Korea.

The complete mitochondrial DNA of an ecologically important crustacean mud shrimp, Upogebia yokoyai (Decapoda, Crustacea) was sequenced. We used next generation sequencing strategy for total genomic DNA and organelle genome pipeline for mitogenome assembly. A newly determined mitogenome was 16,063 bp in total length with 28% of GC content.

Direct linkage between dimethyl sulfide production and microzooplankton grazing, resulting from prey composition change under high partial pressure of carbon dioxide conditions.

Oceanic dimethyl sulfide (DMS) is the enzymatic cleavage product of the algal metabolite dimethylsulfoniopropionate (DMSP) and is the most abundant form of sulfur released into the atmosphere. To investigate the effects of two emerging environmental threats (ocean acidification and warming) on marine DMS production, we performed a large-scale perturbation experiment in a coastal environment. At both ambient temperature and ∼ 2 °C warmer, an increase in partial pressure of carbon dioxide (pCO2) in seawater (160-830 ppmv pCO2) favored the growth of large diatoms, which outcompeted other phytoplankton species in a natural phytoplankton assemblage and reduced the growth rate of smaller, DMSP-rich phototrophic dinoflagellates.

Draft genome sequence of Rubidibacter lacunae strain KORDI 51-2(T), a cyanobacterium isolated from seawater of Chuuk lagoon.

A photoautotrophic cyanobacterium, Rubidibacter lacunae was reported in 2008 for the first time. The type strain, KORDI 51-2(T), was isolated from seawater of Chuuk lagoon located in a tropical area. Although it belonged to a clade exclusively comprised of extremely halotolerant strains by phylogenetic analyses, R.

Application of pyrosequencing method for investigating the diversity of synechococcus subcluster 5.1 in open ocean.

Synechococcus are distributed throughout the world's oceans and are composed of diverse genetic lineages. However, as they are much less abundant than Prochlorococcus in oligotrophic open oceans, their in-depth genetic diversity cannot be investigated using commonly used primers targeting both Prochlorococcus and Synechococcus. Thus, in this study, we designed a primer specific to the 16S-23S rRNA internal transcribed spacer (ITS) of the Synechococcus subcluster 5.

Minke whale genome and aquatic adaptation in cetaceans.

The shift from terrestrial to aquatic life by whales was a substantial evolutionary event. Here we report the whole-genome sequencing and de novo assembly of the minke whale genome, as well as the whole-genome sequences of three minke whales, a fin whale, a bottlenose dolphin and a finless porpoise. Our comparative genomic analysis identified an expansion in the whale lineage of gene families associated with stress-responsive proteins and anaerobic metabolism, whereas gene families related to body hair and sensory receptors were contracted.

Gracilimonas rosea sp. nov., isolated from tropical seawater, and emended description of the genus Gracilimonas.

A Gram-staining-negative, non-motile, spore-forming, rod-shaped, marine bacterial strain, CL-KR2(T), was isolated from tropical seawater near Kosrae, an island in the Federated States of Micronesia. Analysis of the 16S rRNA gene sequence of strain CL-KR2(T) revealed a clear affiliation with the genus Gracilimonas. Based on phylogenetic analysis, strain CL-KR2(T) showed the closest phylogenetic relationship to Gracilimonas tropica CL-CB462(T), with 16S rRNA gene sequence similarity of 96.

Phylogenetic diversity of Synechococcus strains isolated from the East China Sea and the East Sea.

Phylogenetic relationships among 33 Synechococcus strains isolated from the East China Sea (ECS) and the East Sea (ES) were studied based on 16S rRNA gene sequences and 16S-23S rRNA gene internal transcribed spacer (ITS) sequences. Pigment patterns of the culture strains were also examined. Based on 16S rRNA gene and ITS sequence phylogenies, the Synechococcus isolates were clustered into 10 clades, among which eight were previously identified and two were novel.

Pelagibius litoralis gen. nov., sp. nov., a marine bacterium in the family Rhodospirillaceae isolated from coastal seawater.

A Gram-negative, strictly aerobic, slightly curved rod-shaped bacterial strain, designated CL-UU02(T), was isolated from coastal seawater off the east coast of Korea. 16S rRNA gene sequence analysis revealed a clear affiliation of this novel strain with the family Rhodospirillaceae. Strain CL-UU02(T) formed a robust cluster with the type strains of species of the genus Rhodovibrio at 16S rRNA gene sequence similarity levels of 89.

Rubidibacter lacunae gen. nov., sp. nov., a unicellular, phycoerythrin-containing cyanobacterium isolated from seawater of Chuuk lagoon, Micronesia.

A unicellular cyanobacterium, designated KORDI 51-2(T), was isolated from surface seawater of Chuuk lagoon, Micronesia. The cells were wine-coloured rods and emitted red fluorescence under green excitation of an epifluorescence microscope. Thus, morphologically, the strain resembled Synechococcus species.

Nocardioides salarius sp. nov., isolated from seawater enriched with zooplankton.

A rod-shaped marine bacterium, designated CL-Z59(T), was isolated from seawater enriched with zooplankton. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain CL-Z59(T) belongs to the genus Nocardioides, the highest level of sequence similarity (99.2%) being found with respect to Nocardioides marinisabuli KCCM 42681(T).

Nocardioides marinus sp. nov.

A Gram-positive, slightly halophilic, rod-shaped bacterium, designated CL-DD14(T), was isolated from seawater of the East Sea, Korea. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain CL-DD14(T) belongs to the genus Nocardioides. Levels of 16S rRNA gene sequence similarity between strain CL-DD14(T) and the type strains of recognized species of the genus Nocardioides were low (94.