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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
The Korean Society of Oceanography
Editor in Chief :
Volume & Issues
Volume 13, Issue 4 - Nov 2008
Volume 13, Issue 3 - Aug 2008
Volume 13, Issue 2 - May 2008
Volume 13, Issue 1 - Feb 2008
Selecting the target year
Future Natural Resource for Sustainable National Economic Growth: Development of Deep-sea mineral resources
Park, Cheong-Kee ;
The Sea, volume 13, issue 3, 2008, Pages 165~167
Physical Properties of Surface Sediments of the KR(Korea Reserved) 1, 2, and 5 Areas, Northeastern Equatorial Pacific
Lee, Hyun-Bok ; Chi, Sang-Bum ; Park, Cheong-Kee ; Kim, Ki-Hyune ; Ju, Se-Jong ; Oh, Jae-Kyung ;
The Sea, volume 13, issue 3, 2008, Pages 168~177
Trafficablility of a miner and potential environmental impacts due to mining activities should be considered in the selection of a commercial manganese nodule mining site. These two factors can be evaluated comparatively with physical properties and shear strength of sea-bed sediments. For the qualitative comparison of potential minig sites in terms of these two factors, physical properties such as water contents, void ratios, porosities, and grain densities, and shear strengths of surface sediments were determined for the three potential manganese nodule mining sites(KR1, KR2, and KR5) in the Korean manganese nodule contract area, northeast Pacific. For the study, sediment samples were collected from 107 stations from 2004 to 2006. The physical properties of surface sediments showed more significant differences between northern(KR1, KR2) and southern(KR5) blocks than between northern blocks(KR1 vs. KR2). Water content, void ratio, and porosity of sediments from KR5 were relatively higher than those from KR1 and KR2. Grain density of sediments from KR5 was relatively lower than those from KR1 and KR2. Shear strengths of the top 10cm sediments were higher in KR1 and KR2, whereas those of the deeper part were highest in KR5 block. Generally, sediments of high water contents are less suspendible than those of the low water contents by benthic disturbances, thus less disturbance is expected in the sediments of high water content by mining activities. In terms of trafficability, the shear strength of sediment below 10 cm deep is more important than shallower part because miner will disturb at least top 10 cm interval of the surface sediments. Base on these results, we conclude that KR5 area will be the best site for commercial mining among three investigated sites in this study.
Distribution and Remineralization Ratio of Inorganic Nutrients in the Divergence Zone(
), Northeastern Pacific
Son, Ju-Won ; Kim, Kyeong-Hong ; Kim, Mi-Jin ; Son, Seung-Kyu ; Chi, Sang-Bum ; Hwang, Keun-Choon ; Park, Yong-Chul ;
The Sea, volume 13, issue 3, 2008, Pages 178~189
The distribution of inorganic nutrients and their remineralization ratio in the divergence zone (
) of the northeastern Pacific were investigated from July 2003 to July 2007. A divergence zone along the boundary of the North Equatorial Counter Current (NECC) and North Equatorial Current (NEC) at
was observed in July 2007 when the La Nina event and divergence-related upwelling was strong. The mean depth of oligotrophic surface mixed layer in the divergence zone was 46, 61, and 30 m in July 2003, August 2005, and July 2007, respectively. Below the surface mixed layer, a nutricline was clearly observed. The depth integrated value of nitrate including nitrite (DIVn) in the upper layer(
m depth) ranged from 5.51 to 21.71
) in July 2003, from 5.62 to 8.46
) in August 2005, and from 8.98 to 27.80
) in July 2007. The maximum DIVn was observed at the divergence zone. The distributions of phosphate(DIVp) and silicate(DIVsi) were similar to that of DIVn and the DIVn/DIVsi ratio was
in the upper layer. The limiting nutrient for phytoplankton growth in the study area was identified as nitrogen(N/P ratio=14.6). The nitrate (including nitrite) concentrations were lower in the region mainly affected by NEC than in the region affected by NECC. The study area of low silicate concentrations was also considered to be Si-limiting environment. The remineralization ratios of nutrients were
in the study area. These ratios suggested remineralization process in the surface layer of divergence zone.
Hydrographic Structure Along
in the Northeastern Pacific in July-August 2005
Shin, Hong-Ryeol ; Hwang, Sang-Chul ;
The Sea, volume 13, issue 3, 2008, Pages 190~199
To investigate hydrographic structure and characteristics of the tropical ocean in the eastern and the western Pacific, CTD(Conductivity-Temperature-Depth) data along
in July-August 2005 were analyzed. Sea surface temperature along
in summer is highest in the Equatorial Counter Current(ECC) because of the high-temperature water greater than
moving through the ECC from the western Pacific to the eastern Pacific in spring and summer. Based on the evidence of the presence of low salinity and high dissolved oxygen water in the North Equatorial Current(NEC), we suggested that the low salinity water moved from the Gulf of Panama to the east of Philippine along the North Equatorial Current(NEC). The South Equatorial Current(SEC) had the most saline water from surface to deep layer because the saline water from the Subtropical South Pacific Ocean moved to the north. The salinity minimum layer was observed at 500-1500 m depth along
. The water mass with the salinity minimum layer in the north of
came from the North Pacific Intermediate Water(NPIW) and that in the south of
came from the Antarctic Intermediate Water(AAIW), which was more saline than the NPIW. Cyclonic cold eddy with a diameter of about 200km was found in
. Sea surface temperature along
in the eastern Pacific was lower than along
in the western Pacific; on the other hand, sea surface salinity in the eastern Pacific was higher than in the western Pacific. Subsurface saline water from the Subtropical South Pacific Ocean was less saline in the eastern Pacific than in the western Pacific. Salinity and density(
) of the salinity minimum layer south of
was higher in the eastern Pacific than in the western Pacific.
Seasonal Variations of Particle Fluxes in the Northeastern Pacific
Kim, Hyung-Jeek ; Kim, Dong-Seon ; Hyeong, Ki-Seong ; Kim, Kyeong-Hong ; Son, Ju-Won ; Hwang, Sang-Chu ; Chi, Sang-Bum ; Kim, Ki-Hyun ; Khim, Boo-Keun ;
The Sea, volume 13, issue 3, 2008, Pages 200~209
Particle fluxes were measured with a time-series sediment trap from July 2003 to June 2005 at the St. KOMO(KOMO; Korea Deep-Sea Environmental Study Long-Term Monitoring Station,
) in the northeastern Pacific. Total mass fluxes at a depth of 4,960 m showed distinct seasonal variations with high values in the winter(December-February) and spring(March-May) and low values in the summer(June-August) and fall(September-November). Biogenic origin fluxes also displayed distinct seasonal variations similar to total mass fluxes. Particularly, calcium carbonate fluxes in winter and spring were more than two times greater than those in summer and fall. The prominent seasonal variations of total mass and biogenic fluxes were closely related with the seasonal changes of primary production in the surface waters; in winter and spring, primary production increased due to the enhanced supply of nutrients below the surface mixed layer by strong wind and less stratification, whereas it decreased as a result of the less supply of nutrient by reduced wind speed and strong stratification in summer and fall. The seasonal variations of total mass and biogenic fluxes in this study were higher than the differences of total mass and biogenic fluxes caused by the environmental changes such as El
events in the previous studies. In order to understand the effects of El
on the particle flux, therefore, the seasonal variation of particle flux in the northeastern equatorial Pacific needs to be well defined.
Distribution Patterns of Carbon and Nitrogen Contents in the Sediments of the Northeast Equatorial Pacific Ocean
Kim, Kyeong-Hong ; Hyun, Jung-Ho ; Son, Ju-Won ; Son, Seung-Jyu ;
The Sea, volume 13, issue 3, 2008, Pages 210~221
The mesoscale environmental surveys were conducted between
mainly along the
meridian from 1997 to 2002 to investigate controlling factors of carbon and nitrogen contents in bottom sediments. Sediments of the study area showed zonal distribution pattern depending on latitudinal position and can be classified into four types; calcareous ooze(
), siliceous sediments(
), pelagic red clay(
), and mixed sediments(
). Inorganic carbon(IC) contents varied depending on water depth and carbonate compensation depth(CCD). Carbonate materials were well preserved in the low latitude region, where water depths are shallower than CCD. In contrast, the higher latitude region dominated by siliceous sediment and pelagic red clays has low productivity in water column as well as the water depths deeper than CCD. Thus, most of carbonate materials were dissolved, which resulted in IC contents of less than 0.05% in the sediments. Organic carbon(OC) and total nitrogen contents(TN) in siliceous sediments were higher than in pelagic red clay sediments simply because of higher primary productivity in the siliceous sediment dominated area. The contents of OC and TN were lower in the calcareous ooze than in the siliceous sediments. It is attributed to the high input of calcareous material to the bottom due to relatively shallow water depth of the area, which diluted organic matter contents in the sediment. Overall results indicated that water depth relative to CCD, primary production in water column, and sedimentation rate largely controls the large-scale distribution of carbon and nitrogen contents in the study area.
Dynamic Analysis of Underwater Test Collector on Extremely Soft Soil
Kim, Hyung-Woo ; Hong, Sup ; Choi, Jong-Su ; Yeu, Tae-Yeong ;
The Sea, volume 13, issue 3, 2008, Pages 222~228
We conducted a dynamic analysis of an underwater test collector, which operates on extremely soft soil of deep-seafloor. The underwater test collector consists of nodule pick-up device, vehicle tracks, nodule crusher, loading frame and electric-electronic system. The weight of underwater test collector is about 8600 kg. The average normal pressure, that the underwater test collector supports, is about 6.0 kPa. The dynamic analysis model of underwater test collector is developed using commercial software RecurDyn-LM and Visual Fortran 90. A terramechanics model of extremely soft soil is implemented to the software based on user-written subroutine and applied to the dynamic analysis of the underwater test collector model. The dynamic responses of test collector are studied with respect to track velocities, terrain conditions, and coefficients of added mass and drag.
Development of Operating S/W and DBMS for Deep-sea Manganese Nodule Miner
Park, Soung-Jae ; Yeu, Tae-Kyeong ; Yoon, Suk-Min ; Hong, Sup ; Kim, Hyung-Woo ; Choi, Jong-Su ; Kim, Sang-Bong ;
The Sea, volume 13, issue 3, 2008, Pages 229~236
The deep-sea miner is the tracked vehicle system which drives on the deep-seabed and gathers a manganese nodules. The miner is operated by remote control in real-time by the station of surface vessel. So operating S/W is a important part of miner remote operating. At present, the test miner has been designed and manufactured for near-shore sea-test. The test miner consists of mechanical parts, and electric-electronic parts. Because those parts should be controled and monitored remotely, operating S/W for control and monitoring is necessary by all means. In this paper, real-time operating S/W for a control and monitoring of the test miner was designed and developed using PXI, embedded controller and LabVIEW. This real-time operating S/W was developed for an efficient test of test miner in a near seabed area. Moreover, database management system(DBMS) was developed too for the data management of test miner monitoring using MS SQL and LabVIEW.
Coupled Dynamic Analyses of Underwater Tracked Vehicle and Long Flexible Pipe
Hong, Sup ; Kim, Hyung-Woo ;
The Sea, volume 13, issue 3, 2008, Pages 237~245
We developed a computational method on coupled dynamics of tracked vehicle on seafloor and long flexible pipe. The tracked vehicle is modeled as rigid-body vehicle, and the linked flexible pipe is discretized according to a lumped-parameter model. The equations of motion of the rigid-body vehicle on the soft seafloor are combined with the governing equations of flexible pipe dynamics. Four Euler parameters method is used to express the orientations of the vehicle and the flexible pipe. In order to solve the nonlinear coupled dynamics of vehicle and flexible pipe an incremental-iterative formulation is implemented. For the time-domain integration
method is adopted. The total Jacobean matrix has been derived based on the incremental-iterative formulation. The interactions between the dynamics of flexible pipe and the mobility of the tracked vehicle on soft seafloor are investigated through numerical simulations in time domain.
Applying Axiomatic Design to Design Evaluation of a Deep-Sea Manganese Nodule Miner
Choi, Jong-Su ; Hong, Sup ; Kim, Hyung-Woo ; Yeu, Tae-Kyung ; Lee, Tae-Hee ;
The Sea, volume 13, issue 3, 2008, Pages 246~251
The conceptual design evaluation of Deep-Sea Manganese Nodule Miner(DSNM) based on Axiomatic Design was preformed. Functional Requirements(FRs) in functional domain and Design Parameters(DPs) in physical domain were embodied for the given concept design of DSNM. Interactions between FRs and DPs were sequentially analyzed from the first level hierarchy to the lower level hierarchy. The interactions were expressed as design matrices which showed the dependence or independence between FRs and DPs. The results showed that the design of DSNM was not a coupled one, but a decoupled. Finally, it was conceptually verified that DSNM was a good design satisfying the independence axiom of the Axiomatic Design.
Design of a Decentralized Controller for Deep-sea Mining System
Yeu, Tae-Kyeong ; Park, Soung-Jea ; Hong, Sup ; Kim, Hyung-Woo ; Choi, Jong-Su ;
The Sea, volume 13, issue 3, 2008, Pages 252~259
The deep-sea mining system is generally composed of surface vessel, lifting system, buffer, flexible pipe and miner. The mining system can be regarded as a large-scale system in which each subsystem is interconnected to other ones. In order to control a large-scale system, decentralized control approaches have been proposed recently. In this paper, as a basic study on application of decentralized control, firstly, the mining system was modeled in a simplified way. Lifting system and buffer were regarded as a spherical pendulum and the flexible pipe was taken as a two-dimensional linear spring connection. Based on the simplified model dynamics, the mining system can be decentralized two subsystems, the one consisting of surface vessel, lifting system and buffer, and the other, the miner. Next, this paper proposed the design of controller for each decentralized subsystem by regarding the interacting terms as disturbances. The controllers kept the constant distance between two subsystems during the miner was moving on the specified track. Finally, the efficiency of proposed controller was proven through the numerical simulation of the derived model.
Economic Assessment of Manganese Nodules Mining
Hwang, Seog-Won ; Hwang, Jung-Tae ;
The Sea, volume 13, issue 3, 2008, Pages 260~270
The economics of manganese nodules mining was assessed based on 36 scenarios which reflect recent changes of the metal market. Those scenarios included optimistic/neutral/pessimistic prospect for the cost, 2 production scales(1.5 MT and 3 MT) and 6 assumptional paths of future metal prices. A large part of scenarios, in which optimistic or neutral prospect for the cost and metal prices were assumed, showed good economic feasibility of the project. For example, 37.12% of Internal Rate of Return(IRR) was obtained in the scenario of 3 MT production, neutral cost prospect and present metal price maintained in the future.
Strategies for Development of Seafloor Polymetallic Sulphides in Consideration of International Progress
Park, Seong-Wook ; Yang, Hee-Cheol ; Jeong, Hyeong-Su ;
The Sea, volume 13, issue 3, 2008, Pages 271~279
Polymetallic sulphides means hydrothermally formed deposits of sulphide minerals which contain concentrations of metals including, inter alia, copper, lead, zinc, gold and silver. Nautilus is the first company to commercially explore the seafloor polymetallic sulphide deposits. The Company holds exploration licences and exploration applications for more than 370,000
in the jurisdictional seas of Papua New Guinea, Fiji, Tonga, the Solomon Islands and New Zealand along the western Pacific Ocean's Rim of Fire. Neptune Minerals is also a leading explorer and developer in this field, with exploration licences awarded totalling more than 270,000
in the territorial seas or EEZ of New Zealand, Papua New Guinea and the Federated States of Micronesia. These two companies now carry out the most active investment activities for seafloor polymetallic sulphide deposits with a goal of commercial production by 2010. China and Japan carry out exploration activities for the seafloor polymetallic sulphide deposits to secure supplies of strategic metals. China carries out national R&D projects relating to deep sea mineral resources in the world ocean through China Ocean Mineral Resources R&D Association(COMRA). And Japan investigates her own EEZ for exploration of the seafloor polymetallic sulphide deposits. In consideration of aforementioned international activities of coastal nations as well as private companies for exploring the sulphide deposits, Korea shall prepare strategic plans : First, consolidation of the authorities concerned and legislative support; second, determination of main entity of the project; third, securing government's decisive investment of sufficient budget; and lastly, establishment of the mid, long-term plan for development of seafloor polymetallic sulphides deposits.
Examination of Correction Factor for Manganese Nodule Abundance Using the Free Fall Grab and Box Corer
Lee, Gun-Chang ; Kim, Jong-Uk ; Chi, Sang-Bum ; Ko, Young-Tak ; Ham, Dong-Jin ;
The Sea, volume 13, issue 3, 2008, Pages 280~285
Manganese nodule abundance estimated based on operation of a Free Fall Grab(FFG) needs to be corrected to make up for its incomplete recovery of nodule, because FFGs can not recover all the nodules distributed on seabed. The correction factor for nodule abundance was proposed as 1.29 and 1.13 in 1994 and 2002, respectively, mainly based on the analyses of seabed images. In this study we collected manganese nodules using both FFG and Box Corer(BC) at same stations to examine the accuracy of the previous correction factors. It was found that the nodule recovery of the BC was 1.4 times greater than that of the FFG at the same sampling station, suggesting the necessity of re-evaluation of the previously proposed correction factor for FFG. More extensive sampling and improvement of image analysis method are required to improve the precision of nodule abundance correction factor for FFG.
Geotechnical Properties of Pelagic Red Clay in Northeast Equatorial Pacific
Chi, Sang-Bum ; Lee, Hyun-Bok ; Hyeong, Ki-Seong ; Ju, Se-Jong ; Lee, Gun-Chang ; Ham, Dong-Jin ;
The Sea, volume 13, issue 3, 2008, Pages 286~294
In order to understand the physical properties of deep-sea sediments, which mainly consist of pelagic red clays, sediment samples were collected at 24 stations using a multiple corer in the Clarion-Clipperton fracture zone of the northeast equatorial Pacific. The sampled sediment cores were examined for the mass physical properties(i.e. grain size distribution, mean grain size, water content, specific grain density, wet bulk density, void ratio, and porosity) and the geotechnical properties(i.e. shear strength and consistency limits) with the content of biogenic opal and mineral composition. Although KR1 and KR2 areas on the same latitude are logitudinally far from each other, the mass physical properties of these areas are not distinctly different except for shear strengths. The maximum shear strength of surface sediments in KR2 area is higher than that in KR1 due to the appearance of a consolidated lower layer(Unit 3) in the sediment core from KR2.
Effect of Sound Velocity on Bathymetric Data Aquired by EM120(multi-beam echo sounder)
Ham, Dong-Jin ; Kim, Hyun-Sub ; Lee, Gun-Chang ;
The Sea, volume 13, issue 3, 2008, Pages 295~301
Bathymetric data collected using a multi-beam echo sounder during marine scientific survey is essential for geologic and oceanographic research works. Accurate measurment of sound velocity profile(SVP) in water-column is important for bathymetric data processing. SVP can vary at different locations during the survey undertaken for wide areas. In addition, an observational error can occur when different equipments(Sound Velocity Profiler, Conductivity Temperature Depth, eXpendable BathyThermograph) are used for measuring SVP at the same water column. In this study, we used an MB-system software to show changes in bathymetry caused by variation of SVP. The analyses showed that the sound velocity(SV) changes due to the depth and thickness of thermocline had more significant effects on the resulting bathymetric data than those of surface mixed layer. The observational errors between SVP measuring instruments did not cause much differneces in the processed bathymetric data. Bathymetric survey line is better to be established to the direction that the change of temperature can be minimize to reduce the variation of SVP during the data acquisition along the survey line.