• ALGAE
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• v.20 no.4
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• pp.299-304
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• 2005

Morphological observation of a unialgal culture of Lingulodinium polyedrum was conducted under light- and scanning electron microscopes. Lingulodinium polyedrum was redefined as having the thecal formula of APC, Q, 5', 6", 6c, 6s, 5'", 2"" using the reinterpreted tabulation system. In our tabulation system, the Q, which is equivalent to the 3' in the strict Kofoidean system, was treated as an auxiliary platelet because of its considerable morphological variations in culture specimens. Subsequently, apical plates were redefined as plates directly connected to the APC and/or the Q. The 1"' and the 1p in the conventional Kofoidean system were treated as a component of the sulcus (the Ssa) and as an antapical plate (the 1""), respectively. Our reinterpreted tabulation system clearly differentiated extant gonyaulacalean taxa.

• ALGAE
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• v.23 no.2
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• pp.115-118
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• 2008

Cells of the dinoflagellate Peridinium were frequently observed in water samples of Togyo reservoir, and some species were responsible for dense blooms. Recently, we could identify them as P. bipes f. occultatum Lindem. and P. aciculiferum Lemm., considering morphology (Ki et al. 2005a; Ki and Han 2005b): However, some unidentified Peridinium cells with different shapes and body sizes were found among the samples collected during early spring. Here we describe their morphological characteristics such as thecal plate and body size to characterize its taxonomic identity by morphological characters. The formula of epithecal plates was recorded as 4 apical, 2 intercalary and 7 precingular plates (i.e. 4’', 2a, 7’'’') and the epicone in an apical view was symmetric. An apical pore was easy to make out under a light microscope. No cingular displacement was observed. The average body size was 33 $\mu$m in length with a range of 26-36 $\mu$m, and average 26 $\mu$m in width with a range of 21-31 $\mu$m, respectively; the cell was, therefore, shown slightly elongated. This way we identified Peridinium umbonatum Stein, 1883 for the first time from Korean freshwaters.

• ALGAE
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• v.22 no.2
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• pp.57-67
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• 2007

We analyzed the nuclear-encoded large subunit ribosomal RNA gene (LSU rDNA) sequences of 19 dinoflagellates occurring in costal waters off Korea and reconstructed a phylogenetic tree containing 74 representative species from 37 distinct genera. Of these, the LSU rDNA sequences of Amylax triacantha (Jörgensen) Sournia, Gonyaulax verior Sournia (= Amylax diacantha Meunier), Gyrodinium fissum (Levander) Kofoid et Swezy, Katodinium glaucum (Lebour) Lebour III, Noctiluca scintillans (Macartney) Kofoid et Swezy, Oxyphysis oxytoxoides Kofoid, and Pyrophacus steinii (Schiller) Wall et Dale are reported for the first time. Our LSU rDNA tree consistently placed Oxyrrhis marina Dujardin and N. scintillans at the most primitive positions, giving rise to a strongly supported monophyletic group of typical dinoflagellate species belonging to the Dinophyceae. The phylogenetic relationships among the typical dinoflagellates, however, were not resolved in the higher taxonomic levels in general. Only genera at terminal branches were usually supported with high confidence. The Dinophysiales, represented by Dinophysis species and O. oxytoxoides, formed a strongly supported monophyletic assemblage. The Gymnodiniales and Peridiniales were recovered as polyphyletic groupings. Members of the Gonyaulacales were consistently grouped together, but lacked statistical support. Within this order, the Ceratiaceae and Goniodomataceae each formed a monophyletic group, but the Gonyaulacaceae was polyphyletic. The phylogenetic relationships of the Gonyaulacaceae were generally congruent with differences in the combinations of the apical pore complex, hypothecal organization and thecal formula.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.1-7
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• 2005

To resolve some of the most pressing uncertainties of Peridinium identity, morphological characteristics of Korean Peridinium were examined using light and scanning electron microscopy. The Peridinium samples were collected from three different regions of Juam, Sang-sa and Togyo Reservoirs, when seasonal blooms occurred. Formula of the epithecal plate was recorded with 7 precingular, 3 intercalary, and 4 apical plates (4', 3a, 7"). An apical pore, 3 ${\sim}$ 5 ${\mu}m$ in size, was apparently present. The cingulum was easily observed under light microscope, and was considerably offset by about 15 ${\mu}m$ (2 ${\sim}$ 3 times per cingulum width). The sulcus was straight longitudinally and widened apparently towards the antapex. None of spine was found on the surface of the thecal plates on scanning electron micrographs. The average body length was 50.4 ${\mu}m$ with a range of 29 ${\sim}$ 63 ${\mu}m$. The geometric dimension, as designated to the body length:width ratio, was found from calculation to be 1.12 with a range of 1.00 ${\sim}$ 1.35, therefore, the cell was shown slightly elongated. Based on their morphology, the causative organisms of red tides in three different Korean waters were identified as P. bipes f. occultatum, which was reported for the first time in Korea.

• Fisheries and Aquatic Sciences
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• v.3 no.1
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• pp.26-32
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• 2000

Monospecific red tide by a toxic dinoflagellate belonging to the genus Alexandrium occurred at Chindong Bay in the southern coast of Korea and continued from April 6th to 15th in 1997. The ratio of its cell number to total phytoplankton cell number was much higher than $95\%$. This organism was identified as Alexandrium tamarense, although slight morphological differences were found comparing to the original and successive descriptions of the species. We found neither anterior nor posterior attachment pores in these cells of the bloom population. The occurrence of red tide caused by A. tamarense was first reported in Korea. Its plate formula is Po, Pc, 4', 6"c, 8s, 5"' and 2"". Thecal plates are thin with pore-like ornamentation. In those plates, the anterior part of the first apical plate (1') is narrower and its posterior end has sometimes a block-like accessory, but this variation was considered within the range of the morphological variability of this taxon. The cell density during the red tide exhibited a wide range of variation by the depth of water column, ranging from $2\times10^6$ cells$l^{-1}$ to $5\times10^6$ cells·$l^{-1}$. Water temperature varied from 11.8 to $12.3^{\circ}C$. Toxicity of A. tamarense during red tide was measured as $8.8\times10^5$. $MU\;\cdot\;cell^{-1}$ by mouse bioassay.