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.

An Alterative Effect by the Tropical North Atlantic SST in Intraseasonally Varying El Niño Teleconnection over the North Atlantic

Abstract: It is known that there is a distinct intraseasonal variation in wintertime atmospheric responses to El Nino over the North Atlantic, namely a positive North Atlantic Oscillation (NAO)-like response during early winter (November to December) and a negative NAO-like response during late winter (January to March). In this article, we suggest that the tropical North Atlantic (TNAL) sea surface temperatures (SSTs) significantly alter the North Atlantic atmospheric response to El Nino: the warm TNAL SST condition intensifies the negative NAO-like response and vice versa. During late El Nino winters, the TNAL SST tends to increase due to the atmospheric bridge between the tropical Pacific and the Atlantic oceans. The warm tendency in the TNAL SST can intensify the height contrast in the El Nino teleconnection between early and late winter. During early winter (when the response of the TNAL SST to El Nino has not been established yet), atmospheric circulation over the North Atlantic varies widely under various TNAL conditions. Consequently, the average influence of El Nino over the North Atlantic region becomes weaker in the early winter. By contrast, the overall warming over the TNAL region during the late El Nino winter is conducive to the formation of a negative NAO pattern. As a result, the climatic impact becomes stronger during the late winter. Keywords: ENSO teleconnection; NAO; tropical North Atlantic SST (Published: 15 March 2013) Citation: Tellus A 2013, 65 , 19863, http://dx.doi.org/10.3402/tellusa.v65i0.19863

Insight into Antioxidant and Photoprotective Properties of Natural Compounds from Marine Fungus.

Abstract: This computational and experimental work aims to elucidate physicochemical and photophysical natures of free radical scavenging and ultraviolet radiation (UVR) filtering activities of five terpenoids available in the extract of marine fungus. The antioxidant activities of ochraceopone F (C1), aspertetranone D (C2), cycloechinulin (C3), wasabidienone E (C4), and mactanamide (C5) are evaluated by using density functional theory (DFT) at the M05-2X/6-311++G(d,p) level of theory in the gas phase, water, and pentyl ethanoate (PEA). Double antioxidant mechanisms allowing the second (H+/e-) donation such as double hydrogen atom transfer (dHAT), double single electron transfer-proton transfer (dSET-PT), and double sequential proton loss-electron transfer (dSPL-ET) are considered. Reaction enthalpies (ΔrH0), standard Gibbs free energies (ΔrG0) and potential energy surfaces of reactions toward HOO• radical are then established to evaluate the hydrogen transfer (HT) and radical adduct formation (RAF) mechanisms. The computational results are supported by DPPH• and ABTS•+ antioxidant essays. Results show that all compounds C1-C5 are able to scavenge two free radicals via dHAT, dSET-PT, and dSPL-ET mechanisms. Among the compounds, C3 and C4 represent the most potential antioxidants, especially via HAT and RAF mechanisms in all the reaction media. Their rate constants for both HAT and RAF reactions are remarkably higher than that of Trolox and ascorbic acid. The kinetic calculations on activation Gibbs free energies (ΔG⧧) and rate constants (kTST) based on conventional transition state theory (TST) reveal that HAT and RAF processes are in competition in solvents. Photophysical processes occurring during UVR exposure are investigated using the time dependent density functional theory (TD-DFT) combined with UV-vis experiments. The obtained results highlight the promising activities of C1-C5 in UVR absorption in the ranges of UVA and UVB. Among them, C3 and C4 also show better UV absorption properties with the easiest excitations (band gaps equal to 4.06 and 3.65 eV). This study suggests the natural candidates possibly used in organic sunscreen.

Contribution of the development of the stratification of water to the expansion of dead zone: A sedimentological approach

Abstract: To test a hypothesis that the development of the stratification of water enhances the phytoplankton blooming and hypoxia without any increase in the nutrient loading in an enclosed bay, the present study examines the spatial relationship among the hydrographic structures, physico-chemical conditions of the sediments, and macrobenthic communities at 21 stations in the inner part of Ariake Bay, Kyushu, Japan in August 2010, and compares the distribution of the mud content of the sediment in 2014 with those of last few decades focusing on the succession of sedimentary environment. The stratification of water developed in the innermost part of Ariake Bay, and hypoxia occurred below the well-stratified water. The distribution of the muddy bottom with high content of organic matter derived from phytoplankton almost overlapped with the stratified water. Cluster analysis concerning the grain size composition of the sediment corresponded greatly to that of the macrobenthic communities. These results indicate that the development of the stratification of water strongly influences the sedimentary environments and the community structure of macrobenthic animals in the inner part of Ariake Bay. Comparison with the past distribution of mud content revealed eastward expansion of the muddy sediment, and it suggests the distribution of the well-stratified water has expanded recently. The results of the present study show the possibility that the development of the stratified water causes a series of phenomena, which closely resemble ones following the development of the eutrophication of the water, without any increase in the nutrient loading in an enclosed bay or estuary.