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A Gram-negative, nonmotile, aerobic and oxidase- and catalase-positive bacterium, designated D25T, was isolated from the deep-sea sediments of the southern Okinawa Trough area. Phylogenetic analyses of 16S rRNA gene sequences showed that strain D25T fell within the genus Myroides, with 99.2%, 96.0% and 93.4% sequence similarities to the only three recognized species of Myroides. However, the DNA–DNA similarity value between strain D25T and its nearest neighbour Myroides odoratimimus JCM 7460T was only 49.9% (<70%). Several phenotypic properties could be used to distinguish strain D25T from other Myroides species. The main cellular fatty acids of strain D25T were iso-C15:0, iso-C17:1ω9c, iso-C17:03-OH and Summed Feature 3 (comprising C16:1ω7c and/or iso-C15:02-OH). The major respiratory quinone was MK-6. The DNA G+C content was 33.0 mol%. The results of the polyphasic taxonomy analysis suggested that strain D25T represents a novel species of the genus Myroides, for which the name Myroides profundi sp. nov. is proposed. The type strain is D25T (=CCTCC M 208030T=DSM 19823T). [ABSTRACT FROM AUTHOR]

Sinking particles were collected using time-series sediment traps deployed at 350 and 20 mab at Site SB (34° 58.5’N, 139° 20.9’E, 1544 m depth) near the center of Sagami Bay, off Japan with high time resolutions of 5–8 days (March 1997 to August 1998) and 3–4.5 days (March 1998 to August 1998), respectively. The major components (CaCO3, OM, opal, and clay) of these sinking particles and surface bottom sediments were determined using a stepwise leaching method combined with gravimetry. Average total mass fluxes were 1480, 5560 and 3068 mg/m2/year at 350 mab, at 20 mab, and in the surface sediments, respectively, indicating an enhanced collection of sinking particles at 20 mab. Clay was the dominant component and biogenic components (opal+OM+CaCO3) were dominated mainly by opal and secondly by OM. On average, opal and CaCO3 contents decreased gradually as clay content increased with increasing depth from 350 mab–20 mab and in the surface sediments, indicating dissolution of opal and CaCO3 through sinking, rebound, resuspension or sedimentation processes. Thirteen total mass flux peaks at 17-–40-day intervals were observed at 350 mab during the period from March 1997 to August 1998 except for winter, while eight peaks were observed at 20 mab for the period from March 1998 to August 1998. Two types of total mass peaks can be distinguished: one with a clear increase in biogenic flux (opal+OM+CaCO3) and little or no increase in clay flux and termed a bloom type (B-type), and the other with a clear increase in clay flux, little increase in biogenic flux and termed a resuspension type (R-type). Some R-type peaks, but not all, coincided with total mass flux peaks observed at the mouth of Tokyo Bay and suggested the possibility of the effect of particulate materials transported from Tokyo Bay to site SB. The enormously large peak observed at 20 mab in late May 1998 and that at 350 mab in early June 1998 were considered to be due to some physical perturbations from an earthquake swarm near site SB during the period from April to June 1998. The 17-–40-day periodicity was associated clearly with the change in biogenic flux dominated by opal flux and is thought to reflect the periodicity of biological productivity dominated by diatoms in the euphotic zone of Sagami Bay. [Copyright &y& Elsevier]

Abstract: The Gyeongsang Basin is the largest exclusively non-marine sedimentary basin in Korean Peninsula, located in southeastern part of the Peninsula. Its sedimentary setting, magma source, tectonic nature, and formation age are important to understand the Mesozoic tectonic evolution of not only the Sino-Korea Craton, but also the entire Northeast Asia. The Gyeongsang Supergroup, the basin fill, is divided into the Sindong, Hayang, and Yucheon Groups in ascending order. The Sindong and Hayang Groups are composed of sandstone, shale, minor amounts of conglomerate, and marl deposited in a non-marine environment, whereas the Yucheon Group is characterized by the dominance of volcanic rocks. Precise isotopic ages and geochemical analyses are scarce for the volcanic elements of this basin, restricting our understanding of its geodynamic setting and evolution. In this study, we present new U–Pb zircon ages from the volcanic rocks of the Yucheon Group and associated granites in the Gyeongsang Basin. Thirteen volcanic samples yielded ages ranging from 94.4 to 78.4Ma, and four granite samples give ages ∼72Ma. These data confirm that a major magmatic event occurred during Late Cretaceous, and the Gyeongsang volcano-sedimentary complex represents a rock association representing a Late Cretaceous island arc. In comparison with the Sambagawa metamorphic belt, the Jurassic Chichibu accretionary complex (AC) with Cretaceous strike-slip basin sediments, and the Cretaceous Shimanto mélange zone in southwest Japan, it is likely that above-motioned complexes constitute the trace of a continuous subduction-related island arc system in SE Korea extending from SW Japan. Although the peak ages of the magmatic rocks in the eastern part of the North China Craton (NCC) are 130±10Ma, indicating an important time of continental lithospheric thinning under the NCC, the ages of the Gyeongsang magmatic rocks are markedly younger. Late Cretaceous magmatism was very weak in the eastern NCC. Therefore, it is probable that Early–Middle Mesozoic lithospheric thinning beneath the eastern NCC is triggered by multiple tectonic factors, not only by the subduction of the Pacific plate suggested by some previous studies. In addition, 20 inherited/xenocrystic zircons from these volcanic rocks give Archean ages ranging from 2.5 to 2.6Ga, suggesting the existence of late Archean rocks in the Yeongnam Massif. The Yeongnam Massif is predominated by the latest Archean crustal growth at ∼2.50Ga, consistent with the characteristics of the North China Craton. [Copyright &y& Elsevier]