Behavior of marine pipelines under seismic faults     

N.Y Kershenbaum  S.A Mebarkia  H.S Choi   《Ocean Engineering》2000,27(5):132

A new study investigates an unburied offshore “snaked” pipeline behavior under various types of seismic faults. The snaking of the pipeline is caused by the thermal/pressure expansion and soil friction. The snaking takes place at a certain distance from the pipeline's unrestrained end and gradually increases towards the restraint. It is shown that longitudinal seismic faults have less effect on a straight pipeline than a snaked pipeline. The new seismic analysis demonstrates that an increase of ground displacement causes a very small change in bending and longitudinal stresses. The new approach results in a safe, subsea pipeline construction and operation with a significant cost reduction.  相似文献   

Nationwide monitoring of nonylphenolic compounds and coprostanol in sediments from Korean coastal waters     

Minkyu Choi  Hyo-Bang Moon  Sang-Soo Kim  Hee-Gu Choi 《Marine pollution bulletin》2009,58(7):1086-1092

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Genesis and Mineralogy of Serpentinite Deposits,West of South Korea     

Song Suckhwan  Choi Seon Gyu  Lee Hyun Koo 《中国地质大学学报(英文版)》2000,11(2)

The serpentinite deposits derived from ultramafic rockswithin the South Korea mainly occur in the west ofChungcheongnam - Do,the south of South Korea,Ulsan andAndong area,and in the middle of South Korea,Gapyeongarea. The present study is on the genesis and m ineral compo-sitions of the serpentinite deposits consisting of abouteighteenmasses in the west of Chungcheongnam- Do. The ultramaficrocks mainly occur as discontinuously isolated lenticular or el-liptical bodies and extend to NNE d…  相似文献   

Laboratory experiment to measure 5-MHz volume backscattering strengths from Red-tide causing microalgae Chattonella antiqua     

Junghun Kim  Jee Woong Choi  Donhyug Kang 《Ocean Science Journal》2012,47(3):173-179

An acoustic laboratory experiment using 5-MHz signals was conducted to measure the volume backscattering strengths of red-tide causing microalgae, Chattonella antiqua, which is one of the species of harmful algal blooms in the coastal waters of Korea and Japan. The measured backscattering strengths increased with cell abundance, with a slope of approximately 10 dB per decade increase in cell numbers. The density and sound speed ratios of the Chattonella cell to the water medium were estimated via the density gradient centrifugation method and the time-travel difference method, respectively. Finally, the measured backscattering strengths were compared to those predicted by a fluid-sphere scattering model, in which the estimated sound speed and density contrasts were used as input parameters.  相似文献   

Characterizing the effect of heavy metal contamination on marine mussels using metabolomics   总被引：1，自引：0，他引：1  

YK Kwon  YS Jung  JC Park  J Seo  MS Choi  GS Hwang 《Marine pollution bulletin》2012,64(9):1874-1879

Marine mussels (Mytilus) are widely used as bioindicators to measure pollution in marine environments. In this study, (1)H NMR spectroscopy and multivariate statistical analyses were used to differentiate mussel groups from a heavy metal-polluted area (Onsan Bay) and a clean area (Dokdo area). Principal component analysis and orthogonal projection to latent structure-discriminant analysis revealed significant separation between extracts of mussels from Onsan Bay and from the Dokdo area. Organic osmolytes (betaine and taurine) and free amino acids (alanine, arginine, glutamine, phenylalanine, and threonine) were more highly accumulated in Onsan Bay mussels compared with Dokdo mussels. These results demonstrate that NMR-based metabolomics can be used as an efficient method for characterizing heavy metal contamination derived from polluted area compared to clean area and to identify metabolites related to environments that are contaminated with heavy metals.  相似文献   

Copepod feeding in a coastal area of active tidal mixing: diel and monthly variations of grazing impacts on phytoplankton biomass   总被引：1，自引：0，他引：1  

Doo B. Lee  Hye Y. Song  Chul Park  Keun H. Choi 《Marine Ecology》2012,33(1):88-105

This study examined monthly feeding rates and grazing impact on phytoplankton biomass, as well as diel feeding rhythms of four key copepod species in a tidally well mixed estuary (Asan Bay, Korean Peninsula). Monthly ingestion rates estimated based on gut pigment analysis were closely associated with their peak densities, but not with phytoplankton biomass, implying high ingestion may be related to reproductive output for population growth. The three smaller copepods, Acartia hongi, Acartia pacifica and Paracalanus parvus, showed feeding preference for smaller phytoplankton (<20 μm) with higher clearance rates, whereas the larger Calanus sinicus preferred larger phytoplankton. Acartia pacifica and P. parvus showed distinct increased nocturnal feeding rates as measured with gut fluorescence, whereas A. hongi showed no significant day–night differences. Copepod diel feeding patterns were not associated with food quantity, and endogenous physiological rhythm might be hypothesized as responsible for the observed diel feeding patterns. Grazing impact on phytoplankton biomass by the four copepods in the estuary was on average 8% (range 0.2–29.8%) of the phytoplankton standing stock, similar to values reported in other coastal waters. Very high copepod abundances but low daily carbon ration (<20% for all copepods) provided by feeding on phytoplankton indicate that copepods also grazed on other non‐phytoplankton foods in Asan Bay.  相似文献   

Biomass and trophic structure of the plankton community in subtropical and temperate waters of the northwestern Pacific Ocean     

Chang-Rae Lee  Keun-Hyung Choi  Hyung-Ku Kang  Eun Jin Yang  Jae Hoon Noh  Dong Han Choi 《Journal of Oceanography》2012,68(3):473-482

This study examined the biomass structure of autotrophic and heterotrophic plankton along a trophic gradient in the northwestern Pacific Ocean in an attempt to understand planktonic food web structure. Autotrophic biomass exceeded that of heterotrophic organisms in all sampling regions, but with lesser contribution to total planktonic biomass at stations of higher phytoplankton biomass, including the northern East China Sea, compared to the regions of lower phytoplankton biomass. The proportion of the biomass of heterotrophic bacteria, nanoflagellates (HNF), and dinoflagellates (HDF) relative to that of phytoplankton was all inversely related to phytoplankton biomass, but positive relationships were observed for both ciliates and mesozooplankton. Mesozooplankton biomass inclined greater than phytoplankton along the gradient of phytoplankton biomass, with biomass rise being most closely associated with ciliate and HDF biomass and, to a lesser degree, with large phytoplankton (>3?μm). Both bacteria and picophytoplankton were significantly and positively related to the biomass ratio of mesozooplankton to the sum of HDF and ciliates (i.e., proxy of mesozooplankton predation on protozoans), but no positive relationship was apparent either for HNF or for large phytoplankton. Such relationships may result from predation relief on lower food webs associated with mesozooplankton feeding on protistan plankton.  相似文献   

Effect of the North Atlantic Oscillation on the Pattern of Lake Ice Phenology in Poland     

Dariusz Wrzesiński  Adam Choiński  Mariusz Ptak  Rajmund Skowron 《Acta Geophysica》2015,63(6):1664-1684

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Effects of the modified Huanglian Jiedu decoction on the disease resistance in grey mullet (Mugil cephalus) to Lactococcus garvieae     

W.M. Choi  C.L. Lam  W.Y. Mo  Z. Cheng  N.K. Mak  Z.X. Bian  M.H. Wong 《Marine pollution bulletin》2014

Lactococcosis is prevalent on grey mullet (Mugil cephalus) in Hong Kong aquaculture resulting in serious economic loss. A compound formulation of Traditional Chinese Medicines (TCM) (modified Huanglian Jiedu decoction (HLJDD)) comprising Rhizoma coptidis, Radix scutellaria, Cortex phellodendri, Fructus gardeniae, Fructus forsythiae and Flos lonicerae japonicae (in a ratio of 3:2:2:3:3:5) were applied as feed supplements to deal with the disease. The Nitroblue tetrazolium activity in blood, bactericidal activity and total immunoglobulin in plasma were significantly enhanced after feeding 1% of this TCM for 28 days. The disease resistances to Lactococcus garvieae in 1% and 2% TCM feeding groups were significantly enhanced. In the in vitro study, the modified HLJDD also activated the plasma bactericidal activities (p < 0.01). Based on this study, 1% modified HLJDD feeding for 28 days may be an optimal dose to prevent L. garvieae infection and could be used in aquaculture industries.  相似文献   

Magnetic characteristics of sediment grains concurrently contaminated with TBT and metals near a shipyard in Busan,Korea     

Jin Young Choi  Gi Hoon Hong  Kongtae Ra  Kyung-Tae Kim  Kyoungrean Kim 《Marine pollution bulletin》2014

Bottom sediments near shipyards are often susceptible to receiving accidental spills of TBT and metals or their degradation products from hull scraping of antifouling system paints applied prior to 2008, when the AFS Convention 2001 was not in force. We investigated TBT and metal contamination of sediments near the shipyards of a small marina located in Busan, Korea and found that they were highly contaminated with TBT, Cu, and Zn. To better understand the environmental impacts and to make an optimal remediation plan, we characterized individual antifouling fragments in terms of metal and TBT contents, magnetic properties, and grain-size. Coarse-sized individual antifouling fragments exhibited simultaneously high levels of TBT, metals and high magnetic susceptibility, and appeared to be a major source of pollution in the sediment. Therefore, magnetic separation in combination with size-separation appears to be a cost-effective remediation method to remove the TBT and metals from contaminated shipyard sediments.  相似文献