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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 9, Issue 4 - Nov 2004
Volume 9, Issue 3 - Aug 2004
Volume 9, Issue 2 - May 2004
Volume 9, Issue 1 - Feb 2004
Selecting the target year
Estuarine Behavior and Flux of Nutrients in the Seomjin River Estuary
The Sea, volume 9, issue 4, 2004, Pages 153~163
In order to estimate the nutrient flux of the Seomjin River into the coastal waters of South Sea, and to understand the estuarine reactions during mixing between river water and seawater, we collected surface water along the salinity gradient in the Seomjin River estuary from Mar. 1999 to Apr. 2001. We found that nitrate and silicate were delivered by fluvial input, while phosphate was, supplied from disposed wastes in the Gwangyang Bay. Mean annual flux of dissolved inorganic nitrogen (DIN), phosphate and silicate into the Gwangyang Bay was estimated 10.9 molesㆍsec
), 0.07 molesㆍsec
), 13.3 molesㆍsec
), respectively. An evident removal of phosphate, silicate and ammonium at the mid-salinity zone during the dry season was attributed to the active uptake of phytoplankton, and consequently nutrient flux into the Gwangyang Bay was low. Whereas, during the flood season in summer, conservative or additional distribution of the nutrients was observed in the estuary. As a rsult nutrient flux into the Gwangyang Bay was maintained high. High concentrations of chlorophyll a and the active removal of nutrient during the dry season at the mid-salinity zone suggest that nutrient distribution in the Seomjin River estuary was mainly controlled by biological processes and nutrient fluxes into the Gwangyang Bay might be significantly modified of by the primary production.
Comparative Population Dynamics of Photosynthetic Ciliate Mesodinium rubrum (=Myrionecta rubra) in Gomso Bay and the Geum River Estuary, Korea
The Sea, volume 9, issue 4, 2004, Pages 164~172
Water temperature, salinity, the phytoplankton community and population of a marine photosynthetic ciliate, Mesodinium rubrum (=Myrionecta rubra), were monitored every 0.5-2 weeks in Gomso Bay and the Geum River Estuary from September 1999 to December 2000. Patterns of temporal variation of the M. rubrum population and phytoplankton community were compared with each other in relation to the differences in temporal fluctuation patterns of the water temperature and salinity in the two study areas. Higher population densities and more frequent blooms of M. rub rum in the Geum River Estuary than those in Gomso Bay could be due to the relatively higher nutrient input by freshwater influx in the Geum River Estuary. In the Geum River Estuary which experience more abrupt and irregular fluctuations of salinity, M. rubrum with its greater tolerance to salinity change exhibited increased dominance while neritic diatoms such as Skeletonema costatum, Asterionellopsis glacialis, A. kariana, Chaetoceros debilis, Eucampia zodiacus, Paralia sulcata, Thalassiosira pacifica, T. nordenskioeldii showed decreased dominance compared with those in Gomso Bay. Thus, it is possible that M. rubrum replaces the dominant diatom species in coastal waters where artificial modification of coast lines as in the case of Saemankeum Reclamation Project should increase the frequency as well as the absolute scale of freshwater discharges.
A thought experiment on the Cochlodinium bloom in Korean waters
The Sea, volume 9, issue 4, 2004, Pages 173~178
Chronic Cochlodinium blooms in the southern waters of Korea have brought about considerable economic losses for about a decade, This paper aims to reframe current perspectives on the outbreak mechanism and the remediation schemes through a thought experiment in a context of mass balance and mathematical ecology. Far different explanations emerge from a careful examination of the scientifically unnoticed clues and a through discussion on the phytoplankton conservation equation. Logic of the eutrophication-induced red tide subjects to criticism. It is strongly recommended that the current remediation scheme to exterminate the target species should be rerouted to an environmentally sound competition enhancement tactics. Finally a novel convergence-float-aggregation hypothesis is proposed as an outbreak mechanism.
The Assessment of Trophic State and the Importance of Benthic Boundary Layer in the Southern Coast of Korea
The Sea, volume 9, issue 4, 2004, Pages 179~195
The trophic state of the coastal waters of the southern part of Korea was assessed using biogeochemical data obtained from the National Marine Environmental Monitoring Program conducted by the National Fisheries Research and Development Institute for six years. The trophic state of different areas, analyzed by non-metric multi-dimensional scaling (MDS) analysis, could divide the areas into three groups. Masan Bay, with suboxic water masses and/or the highest concentrations of dissolved inorganic nitrogen and phosphorus occurred, was assessed as being in a hypertrophic state. Ulsan Bay, Onsan Bay, Busan and Jinhae Bay, located near strong point sources, were in a eutrophic state. Other areas, including Tongyong, Yosu, Mokpo and Jeju island, were evaluated as being in a mesotrophic state. During 1997 to 2002, the average values of excess nitrogen, which is the difference between the measured dissolved inorganic nitrogen (DIN) and the corrected DIN using the Redfield ratio, were positive at Ulsan, Onsan, and Busan, where there were inflows from polluted rivers. In contrast, those were negative values in Haengam Bay, Gwangyang Bay and nearby Yosu. This suggests that the limiting element for phytoplankton growth differed among sites. The time series data of excess nitrogen showed gradual decrease over time in the hypertrophic waters, but the opposite trend in the mesotrophic waters. This indicated that the ratio of nitrogen to phosphate varied according to the trophic state of the coastal waters. The enrichment of organic matter in sediment in eutrophic waters would disturb the normal pattern of biogeochemical cycling of nitrogen and phosphate. In order to assess the condition of the coastal environment, the benthic boundary layer should be considered.
Characteristics of Geochemical Processes along the Salinity Gradient in the Han River Estuary
The Sea, volume 9, issue 4, 2004, Pages 196~203
To understand the geochemical processes in the Han River Estuary, distributions and behaviors of nutrients, dissolved organic matters, and uranium were investigated and analyzed during estuarine tidal mixing in June 2000 and February 2001. The distribution of inorganic nutrients showed very dynamic distributional patterns implying an apparent nitrification process and a concave non-conservative mixing along the salinity gradient. Dissolved organic carbon was high in the upstream region and decreased sharply in the low salinity region of around 5 psu. The 3-D fluorescence characteristic of dissolved organic matter showed two distinct fluorophores in the study area. Biomacromolecules originated mainly from the indigenous biochemical processes and geomacromolecules from terrestrial humic materials. In the study area, the distribution of geomacromolecule showed a concave non-conservative property along the salinity gradient presumably due to the flocculation and removal processes in the estuary. Meanwhile, distribution of the dissolved uranium, mainly in the form of stable uranium carbonate complex, also showed a concave non-conservative property along the salinity gradient in the Han River Estuary. From this study, the removal rate of dissolved uranium in the Han River Estuary was estimated to be about 7.1 ton per year.
Accuracy and Stability of Temperature and Salinity from Autonomous Profiling CTD Floats (ARGO Float)
The Sea, volume 9, issue 4, 2004, Pages 204~211
Autonomous profiling CTD floats are a useful tool for observing the oceans. We, however, cannot perform post-deployment calibration of the CTD's attached to the floats, and the assessment of the accuracy and stability of the profile data from the floats is one of the important issues in the delayed mode quality control of the profiles. Variations in salinity in the intermediate level of East Sea is comparable to the accuracy of salinity data required by the international Argo Program, which is 0.01. Therefore, we can assess the credibility of salinity data from the floats deployed in the East Sea using three independent methods while considering the East Sea as a salinity calibration bath. The methods utilized here are 1) comparison of high quality CTD data and float data obtained at similar locations at similar time, 2) comparison of float data obtained at similar locations at similar time, and 3) investigation of long term stability and accuracy of salinity data from parking depths. All three methods show that without any calibration, the salinity data satisfy the accuracy criterion by the Argo Program. While assuming that the intermediate level temperature in the East Sea is as homogeneous as the salinity, we have applied the three methods to temperature data. We found that the accuracy of temperature reading is 0.01
, which is about twice larger than the requirement by the Argo Program, 0.005
. This does not mean that the temperature readings are inaccurate, because the intermediate level temperature does vary spacially and temporally more than the accuracy interval required by the Argo Program. If we take into account the variation in the intermediate level temperature, the accuracy of temperature data from the floats is not significantly different from that proposed by the Argo Program. Therefore, one could use both temperature and salinity profiles from the floats assessed in this study without calibration.