The First Record of Long Headed Eagle Ray, Aetobatus flagellum (Pisces: Myliobatidae) from Korea

Oh, Ji-Na,Kim, Sung,Kim, Choong-Gon,Soh, Ho-Young,Jeong, Da-Wa,Lee, Youn-Ho The Korean Society of Oceanography 2006 Ocean science journal Vol.41 No.1

A specimen of Aetobatus flagellum was collected at Uljin in June 2005 for the first time in Korea. This specimen is characterized by the cephalic fin, the long snout, the dorsal fin between pelvic fins, spiracles on the dorsal side of the disc, the deeply notched nasal curtain and the one row of the teeth in the lower and the upper jaws. And unlike Aetobatus narinari, it does not have any spots on the its dorsal side of the disc. We report this specimen as the first record from Korea and name it 'Bak-jui-ga-o-ri' in Korean.

Description of the Post Larva of Star Pipefish, Halicampus punctatus (Syngnathidae, Gasterosteiformes) First Found in the Southwestern East Sea, Korea

Kim, Sung,Lee, Youn-Ho,Oh, Ji-Na The Korean Society of Oceanography 2006 Ocean science journal Vol.41 No.4

Larval specimens of Halicampus punctatus were collected off Ulsan and Uljin in December 2002 (three specimens) and off Ulsan in December 2003 (one specimen). These specimens are characterized by the following morphological characteristics: rings, 14 + 35 = 49; subdorsal rings, 1 + 3 = 4; dorsal fin rays, 19 - 20; pectoral fin rays, 14 - 15; anal fm rays, 9; head length (HL), 5.8 - 6.7 in the standard length; snout length, 1.9 in HL; snout depth, 3.7 - 5.2 in snout length. The number of caudal fin rays 9 is less than those of the other species in the same genus 10. Wide stripe bands composed of small pigments are shown in the trunk and the tail. Melanophores are not found in the dorsal fin, the pectoral fin, and the anal fin except the caudal fin. The supraoccipital crest is on the head. The frontal ridge is on the dorsal side of front trunk. The blanched ridges on the opercular are fused with a main ridge like a tree branch. A few branched ridges that are small and narrow on the trunk and the tail are fused with the main ridges. We report these specimens as the first record in Korea and name them 'Byeol-sil-go-ki' in Korean.

Injection of an Intermediate Fluid into a Rotating Cylindrical Container Filled with Two-layered Fluid

Na, Jung-Yul,Hwang, Byong-Jun The Korean Society of Oceanography 1996 Journal of the Korean Society of Oceanography Vol.31 No.4

A median-density fluid was injected into the upper layer of a two-layered fluid in a rotating cylindrical container. Several sets of the top and bottom boundary configurations were employed and the flow pattern of each layer including the injected fluid was observed to determine the factors that affect the path of the injected intermediate fluid. The axisymmetric path of the intermediate fluid when the upper layer had a free surface, changed into the asymmetric path with bulged-shape radial spreading whenever either the upper layer or the lower layer had ${\beta}$-effect. The internal Fronds number that controls the shape of the interface turned out to be the most important parameter that determines the radial spreading in terms of location and strength. When the upper and lower layer had the ${\beta}$-effect, convective overturning produced anticyclonic vortices at the frontal edge of the intermediate fluid, and that could enhance the vertical mixing of different density fluids. The intermediate fluid did not produce any topographic effect on the upper-layer motion during its spreading over the interface, since its thickness was very small. However, its anticyclonic motion within the bulged-shape produced a cyclonic motion in the lower layer just beneath the bulge.

Paleoceanographic Records from the Northern Shelf of the East China Sea since the Last Glacial Maximum

Li, Bao-Hua,Park, Byong-Kwon,Kim, Dong-Seon The Korean Society of Oceanography 1999 Journal of the Korean Society of Oceanography Vol.34 No.3

Both benthic and planktonic foraminifera from Core 97-02 obtained in the northern East China Sea are quantitatively analyzed for reconstructing the paleocenography of late Quaternary. Since the earliest time of the core sediment (last not older than 18000 yr B.P.), the paleo-water depth has changed from less than 20 m to near 100 m at present, which is reflected by the benthic foraminiferal assemblages: before 14000 yr B.P., the water depth was shallower than 20 m; from 14000 to 7500 yr B.P., water depth was 20-50 m; and after 7500 yr B.P., water depth was 50-100 m. The foraminiferal fauna also disclose the water mass history: during the last glacial maximum, the water that dominated the study area might be the coastal water; at the end of the last glacial maximum(14000-9500 yr B.P.), the Yellow Sea Cold Water mostly affected this area; then it gave way to the Yellow Sea Warm Current after 9500 yr B.P.; and finally, the warm water has dominated this area since 9500 yr B.P. because of the westward shift and enhancement of the Kuroshio Current.

Numerical Experiments of Ocean Acoustic Tomography in the East Sea of Korea

Han, Sang-Kyu,Na, Jung-Yul,Lee, Jae-Hak The Korean Society of Oceanography 1996 Journal of the Korean Society of Oceanography Vol.31 No.2

Numerical experiments of OAT (Ocean Acoustic Tomography) are carried out in the East Sea of Korea where the canonical ocean has been perturbed by a mesoscale warm eddy and a thermal front. In order to estimate the horizontal and vertical structure of water temperature of the perturbed ocean, the experimental area is divided into 16 cells with 8 pairs of sources and receivers for a horizontal slice and the water column is divided into 8 layers for a vertical slice. The inversely estimated temperature field by using SVD (Singular Value Decomposition) method reveals the eddy and frontal structure clearly. The rms errors of the two horizontal slices are less than $0.4^{\circ}C$ and $1.7^{\circ}C$ at 400 m and 200 m depths, respectively, while the error in the vertical slice is less than $1.0^{\circ}C.$ For better estimation of temperature by OAT method, particularly for the East Sea, a range-dependent ray model should be used to solve the forward problem. At the same time, improvement in computing the refracted ray path between vertical layers is required to obtain more accurate travel time information. The results of the present experiment give rise to a possibility of application of OAT in remote sensing of the ocean thermal structure.

Nutrients and Phytoplankton Blooms in the Southern Coastal Waters of Korea: I. The Elemental Composition of C, N, and P in Particulate Matter in the Coastal Bay Systems

Kang, Chang-Keun,Kim, Pyoung-Joong,Lee, Won-Chan,Lee, Pil-Yong The Korean Society of Oceanography 1999 Journal of the Korean Society of Oceanography Vol.34 No.2

An investigation was conducted to determine limiting nutrients in the bay systems of the southern coastal area of Korea. The elemental composition of C, N, and P in suspended particulate matter was monitored nearly monthly in Chinhae and Koje Bays and seasonally in Deukryang Bay for 2 years. Atomic C:N ratio in particulate matter ranges from 4.3 to 9.6, typical of marine phytoplankton. C:P and N:P ratios vary from the Redfield ratio to 229 (C:P) and 37 (N:P). A constant C:N ratio of 6.87 from regression of particulate C and N concentrations demonstrates that the particulate matter in the systems originates from primary production. C:P and N:P ratios from regression of C on P and N on P are well associated with changes in salinity. The low N:P ratio of 13.1 implies N limitation in the environments of the systems. This seems to result from the low N:P ratio of nutrients released across sediment-water interface. Phytoplankton response, expressed here as the increase of chlorophyll a, to N addition also verifies N limitation for phytoplankton communities. In heavy rainfall season (from June to September), the addition of excessive N via streams into the stratified coastal water proliferates phytoplankton greatly. During the phytoplankton blooms, C:P and N:P ratios are much higher than the Redfield ratio, implying P limitation. This results from the high N:P ratio in nutrients supplied from stream waters. Strong stratification during the blooms also interrupts the supply of nutrients, particularly p, from bottom waters. Dependent upon precipitation, this tendency shows great inter-annual variation.

Observations of the Cheju Current

Suk, Moon-Sik,Pang, Ig-Chan,Teague, William J.,Chang, Kyung-Il The Korean Society of Oceanography 2000 Journal of the Korean Society of Oceanography Vol.35 No.3

The Cheju Current (CC), defined here as a mean eastward flow in the Cheju Strait, mostly carries water of high temperature and salinity originating from the Kuroshio in winter and spring, the Cheju Warm Current Water (CWCW). The strong core of the eastward component of the CC is found close to Cheju Island (Cheju-Do, hereafter) in winter and spring with a peak speed of about 17.0 cm/s. The eastward flow weakens towards the northern Cheju Strait, and a weak westward flow occurs occasionally close to the southern coast of Korea. The volume transport ranges from 0.37 to 0.45 Sv(1 Sv=10$^6$ m$^3$/s) in winter and spring. Seasonal thermocline and harocline are formed in summer and eroded in November. The occurrence of the CWCW is confined in the southern Cheju Strait close to Cheju-Do below the seasonal thermocline in summer and fall, and cold water occupies the lower layer north of the CWCW which is thought to be brought into the area from the area west of Cheju-Do along with the CWCW. Stratification acts to increase both the speed of the CC with a peak speed of greater than 30 cm/s and the vertical shear of the along-strait currents. The strong core of the CC detached from the coast of Cheju-Do and shifted to the north during the stratified seasons. The volume transport in summer and fall ranges 0.510.66 Sv, which is about 1.5 times larger than that in winter and spring. An annual cycle of the cross-strait sea level difference shows its maximum in summer and fall and minimum in winter and spring, whose tendency is consistent with the annual variability of the CC and its transport estimated from the ADCP measurements. Moored current measurements west of Cheju-Do indicate the clockwise turning of the CC, and the moored current measurements in the Cheju Strait for 1530 days show the low-frequency variability of the along-strait flow with a period of about 37 days.

New findings from CREAMS Observations: Water Masses and Eddies in the East Sea

Kim, Kuh,Kim, Kyung-Ryul,Kim, Young-Gyu,Cho, Yang-Ki,Chung, Jong-Yul,Choi, Byung-Ho,Byun, Sang-Kyung,Hong, Gi-Hoon,Takematsu, Masaki,Yoon, Jong-Hwan,Volkov, Yuri,Danchenkov, Mikhail The Korean Society of Oceanography 1996 Journal of the Korean Society of Oceanography Vol.31 No.4

CREAMS (Circulation Research of the East Asian Marginal Seas) is an international research program, which began in 1993 in order to understand the water mass structure and circulation in the East Sea. Since the beginning of CREAMS, there have been four cruises in the summer and two in the winter, covering most parts of the East Sea for the first time in more than 60 years since the historical survey reported by Uda (1934). CREAMS investigations have provided many new insights into the various aspects of oceanographic problems in the East Sea such as water masses, deep sea currents and circulation, eddies, particle fluxes and so on. In this paper, we briefly review understandings before CREAMS and summarize initial new findings from CREAMS expeditions in terms of water masses and currents.

Oxygen Isotope Data of Winter Water in the Western Weddell Sea: Preliminary Results

Khim, Boo-Keun,Park, Byong-Kwon,Kang, Sung-Ho The Korean Society of Oceanography 1998 Journal of the Korean Society of Oceanography Vol.33 No.1

In the western Weddell Sea, winter mixed layer is characterized by near-freezing temperature and higher salinity due to brine injection through sea-ice formation. This layer becomes Winter Water being capped by warmer and less saline Antarctic Surface Water during the sea-ice melt-ing season. In this study, Winter Water was preliminarily identified by the oxygen isotopic com-positions. The ${\delta}^{18}$O values of Winter Water show the progressively increasing trend from south to north in the study area. It presumably reflects the enhanced mixing with Antarctic Surface Water due to the extent of influence by low S'"0 value of sea-ice/glacier meltwater. Correlations between salinity and 6'"0 values of seawater can be used to more generally characterize Winter Water with a view to identification. However, the prediction on the degree of mixing from these relationships needs more detailed isotope data, although this study allows the oxygen isotopic composition of seawater as a tracer to identify the water mass.

Comparative lectin binding patterns of Cochlodinium polykrikoides Margalef

Rhodes, Lesley L.,Cho, Yong-Chul,Cho, Eun-Seob The Korean Society of Oceanography 2000 Journal of the Korean Society of Oceanography Vol.35 No.3

Four different FITC-conjugated lectins were used to visually evaluate lectin binding activity by optical staining quality using confocal laser scanning microscopy (CLSM) of Cochzodinium polykrikoides in nature (wild type) and culture (cultured type). Cells from the field and cultures treated with ConA fluoresced only at the outer cell wall, and the abundance and distribution of the fluorescent signal were similar. Treatment with PWM and HPA did not elicit fluorescence at the cell surface, but the wild type exposed to HPA showed greater binding than did the cultured cells, possibly due to greater concentrations of glucosamine. The wild type cells treated with LBL lectin showed a strong green fluorescence on the cell surface, whereas cultured cells did not. Signal intensity and abundance were greater than for any other lectins tested in this study. These results suggest that wild type and cultured type are significantly different based on surface sugar production. In particular, the wild type cells apear richer in galactosamine-like moieties. Neither glucose nor mannose-like moieties were present in either wild types or cultured cells.