Oxygen penetration through invertebrate burrow walls in Korean tidal flat     

Bon Joo Koo  Chul-Hwan Koh 《Ocean Science Journal》2013,48(4):329-338

Macrofaunal burrows increase the surface area of the sediment-water interface, which has a great impact on the metabolism of aerobic microbes and the oscillation of reduced metabolites within the sediment. Given the importance of macrofauna in surficial sediments, the aim of this study is to examine the effects of burrow architectures on dissolved oxygen diffusion rates in comparison with unburrowed sediment, and thereby to evaluate the theoretical assumption used for modeling solute distribution in the burrow system using field samples. Employing microsensors, horizontal oxygen profiles were measured on a micrometer scale around burrows of seven invertebrates in tidal flats of the west coast of Korea. Oxygen diffusion distance through the burrow walls of seven invertebrates showed spatio-temporal variation with a range of 0.6 to 2.9 mm. Two groups of burrows were identified based on their oxygen diffusive properties relative to unburrowed sediments: 1) oxygen penetration similar to that of ambient sediments and 2) clearly enhanced oxygen penetration. Differences in the diffusive properties of the burrow wall were related to the burrow depth and diameter, existence of mucus lining on the wall, sediment grain size, and tidal phases. Also inhabitant activity was an important factor affecting oxygen penetration, which is discussed in the paper. These results further demonstrate that simplified assumptions (i.e. burrow structures are viewed as direct biogeochemical extensions of the sediment-water interface) may not be exact representation of the nature.  相似文献   

Combined U-Pb SHRIMP and Hf isotope study of the Late Paleozoic Yaminué Complex, Rio Negro Province, Argentina: Implications for the origin and evolution of the Patagonia composite terrane     

Carlos J.Chernicoff  Eduardo O.Zappettini  Joo O.S.Santos  Neal J.McNaughton  Elena Belousova 《地学前缘(英文版)》2013,4(1)

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Pre-stack sea bottom detection and swell correction within an expected hyperbolic range for noisy high-resolution 8-channel airgun seismic data     

Lee  Ho-Young  Koo  Nam-Hyung  Kim  Byoung-Yeop  Kim  Young-Jun  Son  Woohyun  Joo  Yonghwan 《Marine Geophysical Researches》2021,42(1):1-22

Marine Geophysical Research - The Hugin Fracture, discovered in 2011, is an approximately 3.5 km long seafloor fracture in the North Sea. This fracture was unexpected and, due to the...  相似文献   

Carbon dioxide concentration and flux in an urban residential area in Seoul,Korea   总被引：1，自引：0，他引：1  

Moon-Soo Park  Seung Jin Joo  Soon-Ung Park 《大气科学进展》2014,31(5):1101-1112

The carbon dioxide （CO2） concentrations and fluxes measured at a height of 17.5 m above the ground by a sonic anemometer and an open-path gas analyzer at an urban residential site in Seoul, Korea from February 2011 to January 2012 were analyzed. The annual mean CO2 concentration was found to be 750 mg m-3, with a maximum monthly mean concentration of 827 mg m-3 in January and a minimum value of 679 mg m-3 in August. Meanwhile, the annual mean CO2 flux was found to be 0.45 mg m-2 s-1, with a maximum monthly mean flux of 0.91 mg m-2 s-1 in January and a minimum value of 0.19 mg m-2 s-1 in June. The hourly mean CO2 concentration was found to show a significant diurnal variation; a maximum at 0700-0900 LST and a minimum at 1400-1600 LST, with a large diurnal range in winter and a small one in summer, mainly caused by diurnal changes in mixing height, CO2 flux, and surface complexity. The hourly mean CO2 flux was also found to show a significant diurnal variation, but it showed two maxima at 0700-0900 LST and 2100-2400 LST, and two minima at 1100-1500 LST and 0300-0500 LST, mainly caused by a diurnal pattern in CO2 emissions and sinks from road traffic, domestic heating and cooking by liquefied natural gas use, and the different horizontal distribution of CO2 sources and sinks near the site. Differential advection with respect to wind direction was also found to be a cause of diurnal variations in both the CO2 concentration and flux.  相似文献   

A GIS-based logistic regression model in rock-fall susceptibility mapping along a mountainous road: Salavat Abad case study, Kurdistan, Iran   总被引：1，自引：0，他引：1  

Ataollah Shirzadi  Lee Saro  Oh Hyun Joo  Kamran Chapi 《Natural Hazards》2012,64(2):1639-1656

This study describes the application of logistic regression to rock-fall susceptibility mapping along 11?km of a mountainous road on the Salavat Abad saddle, in southwest Kurdistan, Iran. To determine the factors influencing rock-falls, data layers of slope degree, slope aspect, slope curvature, elevation, distance to road, distance to fault, lithology, and land use were analyzed by logistic regression analysis. The results are shown as rock-fall susceptibility maps. A spatial database, which included 68 sites (34 rock-fall point cells with value of 1 and 34 no rock-fall point cells with value of 0) was developed and analyzed using a Geographic Information System, GIS. The results are shown as four classes of rock-fall susceptibility. In this study, distance to fault, lithology, slope curvature, slope degree, and distance to road were found to be the most important factors affecting rock-fall. It was concluded that about 76?% of the study area can be classified as having moderate and high susceptibility classes. Rock-fall point cells were used to verify results of the rock-fall susceptibility map using success curve rate and the area under the curve. The verification results showed that the area under the curve for rock-fall susceptibility map is 77.57?%. The results from this study demonstrated that the use of a logistic regression model within a GIS framework is useful and suitable for rock-fall susceptibility mapping. The rock-fall susceptibility map can be used to reduce susceptibility associated with rock-fall.  相似文献   

Palustrine calcretes of the Cretaceous Gyeongsang Supergroup, Korea: Variation and paleoenvironmental implications   总被引：2，自引：0，他引：2  

In Sung Paik  Hyun Joo Kim 《Island Arc》2003,12(2):110-124

Abstract Mostly siliciclastic lacustrine deposits from five stratigraphically different formations (Jinju Formation, Jindong Formation, Geoncheonri and correlative Hwasan Formations and Dadaepo Formation, in ascending order) in the Cretaceous Gyeongsang Basin, Korea, were examined for aspects of lithofacies and pedogenesis to evaluate the relative influence of geological controls on the development of palustrine calcretes (calcretes formed from palustrine deposits). The pedogenic carbonate development of palustrine deposits in the Gyeongsang Supergroup varies from formation to formation. The highest development is in the Dadaepo Formation and the second is in the Jindong Formation. The lowest development of palustrine calcretes is in the Geoncheonri and Hwasan Formations and the Jinju Formation shows intermediate development. The more negative d¹³C values and the less negative d¹⁸O values of the Dadaepo palustrine calcretes confirm greater pedogenic development in the Dadaepo Formation. That the highest development was in the Dadaepo Formation was attributed to it having the smallest lake size, indicating that lake size is critical to palustrine calcrete development in non‐carbonate lakes under semi‐arid climate. In spite of having the largest lake size, the higher development in the Jindong Formation could have resulted from its lowest lake gradient and most arid paleoclimate. The higher development of palustrine calcretes in the Late Cretaceous deposits (Jindong Formation) than the Early Cretaceous deposits (Jinju Formation) reflect overall increase in aridity throughout the period during the deposition of the Gyeongsang Supergroup. Consequently, the diverse development of the palustrine calcretes in the Gyeongsang Supergroup indicates that the lacustrine settings varied in time and space throughout the evolution of the Cretaceous Gyeongsang Basin. Such variation in palustrine calcrete development according to the change in paleoenvironments may provide a basis to interpret the relative paleoenvironmental condition of lacustrine deposits including paleoclimate, lake size and gradient.  相似文献   

Temporal, Spatial and Geochemical Discriminations of Granitoids in South Korea     

Yong–Joo JWA 《Resource Geology》1998,48(4):273-284

Abstract: Five groups of the Phanerozoic granitoids in South Korea can be deduced from their temporal and spatial distributions: (1) Jurassic granitoids in the Gyeonggi massif, (2) Permo-Jurassic granitoids in the Ogcheon belt, (3) Permo-Jurassic granitoids in the Yeongnam massif, (4) Cretaceous granitoids in the Ogcheon belt, and (5) Cretaceous granitoids in the Gyeongsang basin. Though the granitoids of each group generally show calc-alkaline and orogenic natures, the petrological, geochemical and genetical features are different with each other. The Permo-Jurassic granitoids in the Ogcheon belt have lower contents of Al₂O₃, Fe₂O₃, CaO, P₂O₅, but higher of FeO, FeOT, MgO, K₂O than those in the Yeongnam massif. From higher feature of K₂O, Na₂O+K₂O and K₂O/Na₂O, the Ogcheon belt seems to have been located at closer continent side relative to the Yeongnam massif during Permo-Jurassic time. From lower values of Fe₂O₃/FeO and magnetic susceptibility the granitoids of the Ogcheon belt had been solidified under more reducing environment than those of the Yeongnam massif. The Cretaceous granitoids in the Ogcheon belt have lower contents of TiO₂, Fe₂O₃, FeO, FeOT, CaO and P₂O₅, but higher of MgO, K₂O, Na₂O+K₂O and K₂O/Na₂O than those in the Gyeongsang basin. This feature indicates that the Ogcheon belt would correspond to the continental environment of magma genesis during Cretaceous time. Higher values of Fe₂O₃/FeO and magnetic susceptibility in the Cretaceous granitoids in the Gyeongsang basin suggest that the granitoids had been solidified under highly oxidizing environment. From the particular chemical features of K₂O, Na₂O+K₂O and K₂O/Na₂O, the Permo-Jurassic granitoids in the Ogcheon belt, the Yeongnam massif as well as the Cretaceous ones in the Gyeongsang basin can be categorized to the continental margin type granite. The Jurassic granitoids in the Gyeonggi massif are possibly of collision type, and the Cretaceous granitoids in the Ogcheon belt of post–orogenic, intra–conti–nent type. The Jurassic granitoids in the Gyeonggi massif had been possibly generated by crustal melting during the collision of Gyeonggi massif to the northern Pyeongnam basin block. The Cretaceous granitoids in the Ogcheon belt had been emplaced at the hinterland of the continental margin during post-orogenic stage of the Honam Shear Zone. The Cretaceous granitoids in the Gyeongsang basin are often compared with Japanese Cretaceous?Paleogene granitoids in their geochemical and genetical natures. For the granitoid composition, the granitoids in the Gyeongsang basin are higher in Fe₂O₃, Fe₂O₃/FeO, Na₂O, K₂O, Na₂O+K₂O and K₂O/Na₂O, but lower in Al₂O₃, FeO, MnO, CaO and P₂O₅ than the Japanese granitoids. The contents of TiO₂, FeOT and MgO are similar in both granitoids. This geochemical contrast would imply that the Cretaceous granitoid magmas in the Gyeongsang basin had been originated at closer place to the continent side under more tensional field, and solidified under more oxidizing environment than the coeval Japanese granitoid magmas.  相似文献   

Factors Affecting the Wintering Habitat of Major Fishery Resources in Southwestern Korean Waters     

Jin Yeong Kim  Il Su Choi  Joo Il Kim  Seok Gwan Choi  Young Yull Chun 《Ocean Science Journal》2007,42(1):41-48

We investigated the temperature and salinity effects on the major fish species in the wintering grounds based on trawl surveys and oceanographic observations in the southwestern waters of Korea during March-early April in 2002-2003. The influence area of warm Kuroshio water was limited to the southwestern area of Korea in 2003 with a range of 7.7-16.3°C, 32.54-34.70 of salinity, wider than that of 2002. The number of fish species and density of major fish species in 2003 were higher than in 2002. Geographical estimation showed high proportions of species number and catches in the areas around Jeju Islands, southwestern waters and the southeastern coast of Korea. Five species; silver pomfret (Pampus echinogaster), hairtail (Trichiurus lepturus), anchovy (Engraulis japonicus), small yellow croaker (Larimichthys polyactis) and yellow goosefish (Lophius litulon) were most abundant, composing above 60% of the total catch in 2002 and 2003. More than 50% of catch in the major fish species were mostly distributed in the range of 9.5-11.0°C of temperature and 33.1-33.9 of salinity. Non-parametric estimation for the major species showed the 1st mode around 10°C and the 2nd mode at 8-9°C in 2002 and 11-14°C in 2003. A m o n g major fish species, hairtail was principally composed of juveniles, and larger individuals were caught in southeastern waters. These results are considered to be helpful for the areabased fishery management strategy for the wintering grounds of the Yellow Sea and coastal waters of Korea.  相似文献   

Changes in benthic communities along a presumed pollution gradient in Vancouver Harbour     

Je JG  Belan T  Levings C  Koo BJ 《Marine environmental research》2004,57(1-2):121-135

Samples of macrobenthic organisms were obtained at seven stations on a presumed pollution gradient from the head of Vancouver Harbour through to outer Howe Sound. Polychaetes (83 apparent species) and molluscs (43 apparent species) were the most abundant faunal groups numerically (44.8 and 47.9%, respectively). Molluscs accounted for most of the biomass (87.9%). The following univariate and multivariate methods were used to investigate structural changes in the benthic communities: ANOVA, Abundance-Biomass Comparisons and related statistics, cluster analysis, multidimensional scaling, and the BIOENV procedure. Most of the analyses divided the seven stations into three groups: Port Moody Arm (Inner Harbour): two stations; Inner and Outer Harbour: four stations, and Gibsons (Howe Sound): one station. Further cause-effect investigations are needed to determine the sensitivity to organic pollution of indicator species identified in the survey. However our data correlating benthic community changes to sediment chemistry suggest the inner harbour was dominated by pollution-tolerant species. Depth and sediment grain size were confounding factors for the interpretations.  相似文献   

Effects of several salt marsh plants on mouse spleen and thymus cell proliferation using mtt assay     

Youngwan Seo  Hee-Jung Lee  You Ah Kim  Hyun Joo Youn  Burm-Jong Lee 《Ocean Science Journal》2005,40(4):209-212

In the present study, we have tested the effects of 21 salt marsh plants on cell proliferation of mouse immune cells (spleen and thymus) using MTT assay in culture. The methanolic extracts of six salt marsh plants (Rosa rugosa, Ixeris tamagawaensis, Artemisia capillaris, Tetragonia tetragonoides, Erigeron annus, and Glehnia littoralis) showed very powerful suppressive effects of mouse immune cell death and significant activities of cell proliferationin vitro. Especially, the methanolic extract ofRosa rugosa was found to have fifteen times compared to the control treatment, demonstrating that Rosa rugosa may have a potent stimulation effect on immune cell proliferation. These results suggest that several salt marsh plants includingRosa rugosa could be useful for further study as an immunomodulating agent.  相似文献