Acute toxicity of heavy metals, tributyltin, ammonia and polycyclic aromatic hydrocarbons to benthic amphipodgrandidierella japonica     

Jung -Suk Lee  Kyu -Tae Lee  Gyung Soo Park 《Ocean Science Journal》2005,40(2):61-66

Benthic amphipod,Grandidierella japonica widely inhabits the Korean coastal waters and is developed as a standard test species for sediment toxicity tests. We exposedG . japonica to various pollutants including 4 kinds of inorganic metals (Ag, Cd, Cu and Hg), tributyltin [TBT], ammonia and 7 polycyclic aromatic hydrocarbon (PAH) compounds (acenaphthene, chrysene, fluoranthene, fluorene, naphthalene, phenanthrene and pyrene) to estimate the no observed effect concentration (NOEC) and the median lethal concentration (LC50) of each pollutant during the 96-hour acute exposure. Among all tested pollutants, TBT was most toxic toG. japonica, and Hg was most toxic among inorganic metals. The toxicity of pyrene toG. japonica was greatest among PAH compounds, followed by fluoranthene, phenanathrene, acenaphthene, fluorene and naphthalene. The toxicity of PAH compounds was closely related to their physico-chemical characteristics such as K_ow and water solubility.G. japonica responded adequately to pollutant concentrations and exposure durations, and the sensitivity ofG. japonica to various inorganic and organic pollutants was generally comparable to other amphipods used as standard test species in ecotoxicological studies, indicating this species can be applied in the assessment of environments polluted by various harmful substances.  相似文献   

Late Quaternary sediments on the outer shelf of the Korea Strait and their paleoceanographic implications   总被引：1，自引：0，他引：1  

D. I. Lim  S. Kang  H. S. Yoo  H. S. Jung  J. Y. Choi  H. N. Kim  I. H. Shin 《Geo-Marine Letters》2006,26(5):287-296

Sedimentological and micropaleontological characteristics of core sediments from the outer shelf of the Korea Strait, which connects the northern East China Sea and the East Sea (Sea of Japan), were investigated to elucidate the paleoceanographic environment, especially the timing of the Kuroshio inflow, since the last glacial maximum. The core sediments, containing continuous records of the last 15,000 years, are characterized by a relatively high mud content (more than 50%, on average) and well-developed tide-influenced sedimentary structures. Their mineralogy suggests that the material originated from the paleo-Nakdong River system, which extended across the shelf of the Korea Strait during low sea-level periods. Planktonic foraminifers reveal a series of well-defined changes in paleoceanographic conditions during the late Pleistocene–Holocene. Down-core variations in the abundance of four foraminiferal assemblages, i.e., cold, coastal, tropical–subtropical, and Kuroshio water groups comprising characteristic planktonic species, suggest the occurrence of a distinct paleoenvironmental change in the surface water at 7,000 years b.p., i.e., from 15,000 to 7,000 years b.p., the area was influenced by coastal waters whereas since ca. 7,000 years b.p., it has been under the influence of open-sea water related to the Kuroshio Current flow, associated with both higher temperature and higher salinity. In particular, Pulleniatina obliquiloculata increased markedly in abundance at this time, documenting the inflow of the Kuroshio into the study area. These data indicate that the coastal water stage terminated at ca. 7,000 years b.p. when the warm Kuroshio and its major branch, the Tsushima Current, began to flow into the East Sea, as is the case today. The intrusion of the Tsushima Current through the Korea Strait after ca. 7,000 years b.p. resulted in abrupt changes in sedimentation rates and a dramatic increase in abundance of the Kuroshio indicator species, P. obliquiloculata.  相似文献   

An analytical solution for the local suspended sediment concentration profile in tidal sea region   总被引：1，自引：0，他引：1  

Kyung Tae Jung  Jae Youll Jin  Hyoun-Woo Kang  Ho Jin Lee 《Estuarine, Coastal and Shelf Science》2004,61(4):657-667

The time-averaged and oscillatory solutions of the one-dimensional vertical (1DV) advection–diffusion equation for the suspended sediment have been derived analytically in a tidal sea region of finite water depth. The basic equation assumes constant eddy diffusivity and settling velocity. No net flux condition is set at the sea surface, while a boundary condition with the erosion rate and depositional velocity is prescribed at the sea bottom. The time-averaged solution has been derived in a straightforward manner, while the advection–diffusion equation governing the oscillatory concentration has been first transformed to a simple diffusion equation and then solved using the Galerkin-eigenfunction method. The former is given in a closed form, while the latter is presented in a series solution.A set of calculations has been performed to examine the change in the vertical structure as well as magnitude of the concentration response function. A possible use of the solution to make an estimate of the erosion rate at the sea bottom based on the concentration information at the sea surface is discussed.  相似文献   

Experiments in ocean circulation modelling     

Ruby Krishnamurti  Jung Yul Na 《地球物理与天体物理流体动力学》2013,107(1):13-21

Abstract

In a laboratory model ocean, fluid in a rotating tank of varying depth is subjected to “wind-stress”, For a certain range of the parameters, Ekman number E and Rossby number R, a homogeneous fluid displays steady, westward intensified flow. For the same range of E and R, a two-layer fluid can have baroclinic instabilities. The parameter range for the various kinds of instabilities is mapped in a regime diagram. The northward transport in the western boundary current is measured as it varies with Rossby number for both homogeneous and two-layer fluid.  相似文献   

Analytical solution for the response of a flexible retaining structure with an elastic backfill     

Chulmin Jung  Antonio Bobet  Gabriel Fernández 《国际地质力学数值与分析法杂志》2010,34(13):1387-1408

An extension of an existing analytical solution for the response of a flexible retaining wall subjected to seismic loading is presented. The solution is based on the assumption that the wall and the soil remain elastic and that there are no shear stresses at the wall–soil interface while the contact remains tied. In addition to the wall displacements due to bending, the wall can experience rigid‐body motions due to rotation and horizontal and vertical movements. The solution is verified by comparing its results with those of a finite element method. Results from the analytical solution together with those of the (FEM) are used to identify and quantify the relative importance of key parameters on the seismic response of a wall. The study shows that wall flexibility and horizontal rigid‐body motions of the wall and frequency content of the seismic input have a significant effect on the wall loads. The pressures behind a rigid wall decrease as the wall rotates about its base, whereas for a flexible wall, the soil pressures decrease as the friction between the backfill and the wall increases. The rigid‐body vertical movements of a wall have little impact on the dynamic pressures induced in the wall, except for a flexible wall where, when prevented, the dynamic loads may be reduced. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Hydrological effects of climate change,groundwater withdrawal,and land use in a small Korean watershed     

Kil Seong Lee  Eun‐Sung Chung 《水文研究》2007,21(22):3046-3056

The effects of variability in climate and watershed (groundwater withdrawal and land use) on dry‐weather streamflows were investigated using SWAT (Soil and Water Assessment Tool). The equation to predict the total runoff (TR) using climate data was derived from simulation results for 30 years by multiple regression analysis. These may be used to estimate effects of various climate variations (precipitation during the dry period, precipitation during the previous wet period, solar radiation, and maximum temperature). For example, if daily average maximum temperature increases by 3 °C, TR during the dry period will decrease by 27·9%. Similarly, groundwater withdrawals strongly affect streamflow during the dry period. However, land use changes (increasing urbanization) within the forested watershed do not appear to significantly affect TR during the dry period. Finally, a combined equation was derived that describes the relationships between the TR during the dry period and the climate, groundwater withdrawal and urban area proportion in a small monsoon watershed. This equation will be effective to predict the water availability during the dry periods in the future since it is closely related to changes of temperature, precipitation, solar radiation, urban area ratio, and groundwater withdrawal quantity. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Application of GRACE to the estimation of groundwater storage change in a data-poor region: A case study of Ngadda catchment in the Lake Chad Basin     

Alla Skaskevych  Jejung Lee  Hahn Chul Jung  John Bolten  John L. David  Frederick S. Policelli  Ibrahim B. Goni  Guillaume Favreau  Soma San  Charles M. Ichoku 《水文研究》2020,34(4):941-955

The present study is to explore the feasibility of GRACE-based estimation of a groundwater storage change in a data-poor region using a case study of the Ngadda catchment in the Lake Chad Basin. Although the Ngadda catchment has only one set of in situ time series data of groundwater from 2006 to 2009 and a limited number of groundwater measurements in 2005 and 2009, GRACE-based groundwater storage change can be evaluated against the in situ groundwater measurements combined with specific yield data. The cross-correlation analysis in the Ngadda catchment shows that maximum rainfall reached in July and August, whereas both the maximum total water storage anomaly and the maximum groundwater storage anomaly occurred 2months later. Whereas the mean annual amplitude of total water storage anomaly is about 17cm from both the average total water storage anomaly from three mascon products and the one from three spherical harmonic products, the mean annual amplitude of soil moisture storage anomaly is substantially varied from 5.58cm for CLM to about 14cm for NOAH and Mosaic. The goodness-of-fit tests show that CLM soil moisture produces the closest estimation of groundwater storage anomaly to the in situ groundwater measurements. The present study shows that GRACE-based estimation for groundwater storage anomaly can be a cost-effective and alternative tool to observe how groundwater changes in a basin scale under the limitation of modelling and in situ data availability.  相似文献   

The anatomy of natural disasters on online media: hurricanes and wildfires     

Olynk Widmar  Nicole  Rash  Kendra  Bir  Courtney  Bir  Benjamin  Jung  Jinho 《Natural Hazards》2022,110(2):961-998

Natural Hazards - Increasing prevalence and scale of natural disasters fuel the need for new approaches to evaluating, and eventually mitigating, their impact. This analysis quantifies and compares...  相似文献   

Sustainable energy transition in developing countries: the role of energy aid donors     

Jung Eun Kim 《Climate Policy》2019,19(1):1-16

Dialogues on global climate policy are increasingly discussing the sustainable energy transition, with Goal 7 of the UN’s Sustainable Development Goals highlighting the importance of affordable and clean energy. This study looks at foreign aid as a carrier of global climate policy and examines donor behaviour in the energy sector. By examining donor behaviour when giving energy aid, one can grasp how the donor community helps recipients achieve a sustainable energy transition. A panel of donor–recipient pairs, covering 29 donors and 99 recipients, was constructed for the period between 1996 and 2013, using data from Organisation for Economic Co-operation and Development Creditor Reporting System (OECD CRS), International Energy Agency (IEA) and World Development Indicators (WDI). The pair-year panel data were empirically analysed using a two-part model to test whether energy aid donors respond to recipients’ needs with regard to renewable energy and residential electricity. The findings demonstrate that donors respond to recipients’ sustainable energy needs, both renewable and residential, when selecting recipients. Moreover, donors tend to increase the amount of aid based on renewable energy needs. The findings also highlight the significant role of international climate policy, as donors have changed their energy aid-giving patterns since the start of the Kyoto Protocol. Contrary to the common belief in the aid-giving literature, this study shows that, with regard to energy aid, donor interests are more weakly related to recipient selection than are recipient needs.

Key policy insights

• Donors are influenced by the residential energy needs of recipients when giving energy aid, which aligns with the Sustainable Development Goals.

• Donors’ energy aid-giving patterns changed between the periods before and after entry into force of the Kyoto Protocol, highlighting the significant role of international climate change policy.

• Policy makers and aid practitioners can steer donors to continue to allocate resources to the development of recipients’ energy policy and to help recipients prepare institutional structures to attract private investment in sustainable energy.

  相似文献   

Doing community geography     

Fischer  Heather  Block  Daniel  Bosse  Amber  Hawthorne  Timothy L.  Jung  Jin-Kyu  Pearsall  Hamil  Rees  Amanda  Shannon  Jerry 《GeoJournal》2021,87(2):293-306

Community Geography offers researchers, community groups, and students opportunities to engage in action oriented applied geographical research. Creating and sustaining these research programs can be challenging, programs can involve many partners from both academic and the community, have different goals and purposes, and utilize a variety of methods to perform research. In this paper we offer a framework of three primary overarching principles for implementing CG projects; (1) Who, (2) Why, and (3) How. (1) “Who” describes who is involved in CG, including researchers, community partners, academic institutions, (2) “Why” describes the justifications and benefits of taking this approach. (3) “How” explains how CG borrows methodologies from many disciplines within geography and beyond. Our examples are not exhaustive; rather, they serve as starting points to inspire researchers interested in CG.

  相似文献