Oceaniglobus Trochenteri sp. nov., Isolated from the Gut Microflora of top Shell (Trochus Maculatus Linnaeus).

A Gram-stain negative, non-flagellated, beige-pigmented, circular, catalase-positive, oxidase-positive bacterium, designated G4T, was isolated from gut microflora of top shell (Trochus maculatus Linnaeus) collected from Diwanggong market, Weihai, PR China. The novel isolate was able to grow at 4–42°C (optimum 25–33°C), pH 7.0–9.0 (optimum 6.5–7.0) and with 0.0–11.0% NaCl (optimum 2.0–3.0%, w/v). Analysis of 16S rRNA gene sequence revealed that strain G4T shared the highest 16S rRNA gene sequence similarities with Oceaniglobus YLY08T (96.6%), followed by Oceaniglobus indicus 1-19bT (95.3%). The genome of strain G4T, with 32 assembled contigs, was 4.5 Mb long with a G + C content of 65.3 mol%. DNA–DNA hybridization values of the isolate against the closely related type strains were far below the 70% limit for species delineation. The average amino acid identity, average nucleotide identity and digital DNA-DNA genome hybridization relatedness between strain G4T and the closely related members of the genus Oceaniglobus, Oceaniglobus indicus1-19bT and Oceaniglobus ichthyenteri YLY08T were 71.3, 76.4 and 20.0%, and 75.0, 76.3 and 19.4%. The major cellular fatty acid was summed feature 8 (C18:1ω7c and/or C18:1ω6c). The sole respiratory quinone detected was Q-10. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and phosphatidyldimethylethanolamine. The results of phenotypical, phylogenetic and biochemical analyses indicated that strain G4T represents a novel species in genus Oceaniglobus within the family Rhodobacteraceae, for which the name Oceaniglobus trochenteri sp. nov. is proposed. The type strain is G4T (= MCCC 1K04356T = KCTC 82506T).

The Northward Habitat Expansion of the Korean Top Shell Turbo sazae (Gastropoda: Vetigastropoda: Turbinidae) in the Korean Peninsula: Effects of Increasing Water Temperature

Recent global climate change often leads to poleward expansions of habitat range of marine organisms in response to increasing water temperature at high latitude. This study investigated latitudinal distribution patterns of Turbo sazae from 2009 to 2018 along the southern and eastern coasts of Korea to verify whether gradual increases in seawater temperature in the East Sea/Sea of Japan (hereafter East/Japan Sea) accelerate changes in the geographic distribution of T. sazae. Between 2009 and 2018, underwater SCUBA surveys were conducted at 19 subtidal rocky shore habitats from the southern and eastern coast of the Korean Peninsula, including Jeju Island. Additionally, long-term seawater temperature records over the last 40 years (between 1980s and 2010s) from the East/Japan Sea were analyzed to verify how changes of water temperature corresponded to geographical distributions of T. sazae. The habitat range of T. sazae was found to have extended from latitude 34°02′ N to latitude 37°06′ N from 2009 to 2018. Although seawater temperature has gradually increased since the 1990s in the East/Japan Sea, habitat expansion was particularly evident during the rapid rise of coastal seawater temperature in the 2010s. Because the strong northward expansion of the Tsushima Current can accelerate the rise of seawater temperature in the East/Japan Sea, studies of the effects of climate change on marine ecosystems of the Korean Peninsula should include data from monitoring the dynamics of the Tsushima Current.