Korean Ocean Research and Development Institute

About: Korean Ocean Research and Development Institute is a facility organization based out in Busan, South Korea. It is known for research contribution in the topics: Sea surface temperature & Gene. The organization has 1770 authors who have published 3032 publications receiving 50142 citations.

Frontal Circulation and Westward Transversal Current at the Yellow Sea Entrance in Winter

Abstract: [1] During the wintertime monsoon, a tongue-shaped thermohaline front is established at the Yellow Sea (YS) entrance where the Cheju Warm Current (CWC) water, originating in the Kuroshio, and the YS cold water meet. The frontal circulation as well as the frontal structure has been investigated by analyzing comprehensive conductivity-temperature-density data, float tracks, current data, and wind data. The front develops by the westward advance of the CWC water, but it is bounded by the shallow Changjiang Banks (CB) that acts like a stopper in the deep part of the YS entrance. The northern part of the tongue-shaped front displays a wave-like motion of 20 km in amplitude and 80 km in wavelength and isotherms, isohalines, and isopycnals are declined downward toward the north. The geostrophic current field indicates formation of a cyclonic circulation along the front which consists of a westward transversal current (TC) along 34°N and a southeastward outflow along the 50 m isobath of the CB. The westward trajectories of floats along the northern front support existence of the TC and a superposition of float tracks evidences cyclonic frontal circulation. The new observational findings of the TC and the cyclonic circulation do not match the classical paradigm of a northerly wind-driven circulation which consists of the northward inflow through the central trough and the southward outflow on the coastal sides. The cyclonic turning of the cold water around the warm tongue stands in contrast with the anticyclonic rounding of the warm CWC water around Jeju-do.

Experimental and numerical study of a dual configuration for a flapping tidal current generator

Abstract: In this study, we conduct experimental and consecutive numerical analyses of a flapping tidal current generator with a mirror-type dual configuration with front-swing and rear-swing flappers. An experimental analysis of a small-scale prototype is conducted in a towing tank, and a numerical analysis is conducted by means of two-dimensional computational fluid dynamics simulations with an in-house code. An experimental study with a controller to determine the target arm angle shows that the resultant arm angle is dependent on the input arm angle, the frequency, and the applied load, while a high pitch is obtained simply with a high input arm angle. Through a parametric analysis conducted while varying these factors, a high applied load and a high input arm angle were found to be advantageous. Moreover, the optimal reduced frequency was found to be 0.125 in terms of the power extraction. In consecutive numerical investigations with the kinematics selected from the experiments, it was found that a rear-swing flapper contributes to the total amount of power more than a front-swing flapper with a distance of two times the chord length and with a 90° phase difference between the two. The high contribution stems from the high power generated by the rear-swing flapper, which mimics the tail fin movement of a dolphin along a flow, compared to a plunge system or a front-swing system, which mimics the tail fin movement of a dolphin against a flow. It is also due to the fact that the shed vorticities of the front-swing flapper slightly affect negatively or even positively the power performance of the rear-swing system at a given distance and phase angle.

Ligulate Desmarestia (Desmarestiales, Phaeophyceae) revisited: D. japonica sp. nov. and D. dudresnayi differ from D. ligulata.

Abstract: The phylogeny of ligulate and sulfuric-acid containing species of Desmarestia, occurring worldwide from polar to temperate regions, was revised using a multigenic and polyphasic approach. Sequence data, gametophyte characteristics, and sporophyte morphology support reducing a total of 16 taxa to four different species. (1) D. herbacea, containing broad-bladed and highly branched forms, has dioecious gametophytes. The three other species have monoecious gametophytes: (2) D. ligulata which is profusely branched and, except for one subspecies, narrow-bladed, (3) Japanese ligulate Desmarestia, here described as D. japonica sp. nov., which is morphologically similar to D. ligulata but genetically distant from all other ligulate taxa. This species may have conserved the morphology of original ligulate Desmarestia. (4) D. dudresnayi, including unbranched or little branched broad-bladed taxa. A figure of the holotype of D. dudresnayi, which was lost for decades, was relocated. The taxonomy is complemented by a comparison of internal transcribed spacer and cytochrome c oxidase subunit I (cox1) as potential barcode loci, with cox1 offering good resolution, reflecting species delimitations within the genus Desmarestia.

Cytotoxic psammaplysin analogues from a Suberea sp. marine sponge and the role of the spirooxepinisoxazoline in their activity.

Abstract: Seventeen bromotyrosine-derived metabolites, including eight new compounds, were isolated from a Micronesian sponge of the genus Suberea. Four of the new compounds were psammaplysin derivatives (10–13), and the other four were ceratinamine derivatives (14–17). Of the compounds obtained, the psammaplysins exhibited cytotoxicity against human cancer cell lines (GI50 values down to 0.8 μM), while the ceratinamine and moloka’iamine analogues showed almost no activity. These results suggest that the spirooxepinisoxazoline ring system is a requirement for cytotoxicity and, therefore, may serve as an attractive molecular scaffold for the development of a potent anticancer agent.