• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.19 no.4
• /
• pp.232-242
• /
• 2014

We investigated the interspecific competition between the harmful dinoflagellate Cochlodinium polykrikoides and diatom Skeletonema sp. based on the utilization and uptake of dissolved organic nutrients. C. polykrikoides and S. costatum were able to grow using dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) as well as dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP). This result indicates that the utilization of dissolved organic nutrients may play a role in surviving strategy in the DIN or DIP-limited environments. The half-saturation constants (Ks) of urea and glycerophosphate (glycero-P) calculated from uptake kinetics experiment of C. polykrikoides was lower than those of Skeletonema sp. This result indicates that Skeletonema sp. have higher affinity for dissolved organic nutrients, such as urea and glycero-P, than C. polykrikoides. Although Skeletonema sp. have higher affinity of dissolved organic nutrients, C. polykrikoides could effectively uptake for urea and glycero-P at sub-saturating nutrient concentrations (${\alpha}$ (${\rho}_{max}/Ks$) of C. polykrikoides was higher than Skeletonema sp.. Therefore, C. polykrikoides by utilization and effectively uptake of dissolved organic nutrients under monoculture may have an advantageous position in the interspecific competition with Skeletonema sp. in the low nutrient environments.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.20 no.2
• /
• pp.92-101
• /
• 2015

We investigated cause of non-outbreak of Cochlodinium polykrikoides blooms in the western coast of Jaran Bay during summer, 2013, based on the species competition among C. polykrikoides and Skeletonema sp. using a mathematical model. As a result of the model simulation where the nutrient conditions in Jaran Bay was applied during summer, the cell density of Skeletonema sp. was higher than that of C. polykrikoides. In the sensitivity analyses by doubling and halving the parameters, any parameter had little effect on the cell density of C. polykrikoides. The cell density of Skeletonema sp. was significantly affected by changes in the parameter values. These results indicated that the growth of C. polykrikoides could be unaffected by rapidly changing environments. However, the growth of Skeletonema sp. may have been promoted by the changing nutrient supply of coast environments. Therefore, C. polykrikoides might have been suppressed by diatom blooms, such as Skeletonema sp., in changing nutrient supply condition of Jaran Bay.

• 한국해양학회지
• /
• v.15 no.2
• /
• pp.100-107
• /
• 1980

1974년 9월부터 1980년 1월까지 6년간 진해만에서 식물성플랑크톤 개체군의 생태적 천이에 관하여 조사하였다. 1974년 9월∼1975년 5월에는 천이계열이 Skeletonema costatum-Eucampia zodiacus Chaetoceros spp.-Nitzschia pungens- Leptocylindrus danicus, 1976년 7월-1978년 5월 Skeletonema costatum-Thalassiosira hyalina- Chaetoceros spp. -Leptocylindrus danicus(Nitzschia pungens), 1978년 7월-1980년 1월 Chaetoceros socialis-Skeletonema costatum-Chaetoceros spp. -Leptocylindrus danicus-Skeletonema costatum(Biddulphia mobiliensis)으로 천이계열이 바뀌어가고 있으며 이들은 계절에 따라 수온의 변화와 밀접한 관계가 있었다. 최근에는 이 해역에서 Skeletonema costatum이 계절에 관계없이 대량출현하여 이 종에 의해 점점 성숙한 천이계열을 형성해 가고 있다.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.21 no.1
• /
• pp.1-8
• /
• 2015

We investigated the effect of monochromatic light emitting diode (LED) on the growth of diatoms Nitzschia sp., Phaeodactylum tricornutum, Skeletonema sp. and green algae Chlorella vulgaris. The four microalgae species were cultured under blue LED (450 nm), yellow LED (590 nm), red LED (650 nm) and fluorescent lamp (mixed wavelengths). The maximum growth rates and cell densities of Nitzschia sp., P. tricornutum and Skeletonema sp. were highest under blue LED, followed by fluorescent lamp, red LED and then yellow LED, however those of C. vulgaris were highest under red LED. This result indicates that blue LED is favorable for the growth of diatoms. Thus, the growth of microalgae under monochromatic light might be species-specific or taxon-specific. Also, these results could be used as an important information in future for remediation of heavy metal contamination in the sediments using LED and microalgae.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.5
• /
• pp.514-522
• /
• 2020

To understand the ecotoxicological differences between representative Skeletonema sp. and Dunaliella tertiolecta, both producers as international standard test species for marine ecotoxicity testing, we compared each standard test method, and comparatively analyzed the suitability of the species for environmental assessment and their sensitivity to various test substances. Although most of the test conditions were the same in each method, there were differences in limitation of pH changing and the initial inoculation density in the validation criteria, which is supposed to originate from the low growth rate of D. tertiolecta. In terms of suitability, both species showed consistency in test performance by repeatedly meeting the validation criteria required by the standard test methods. The salinity ranges available for testing were 20 and 10 psu for Skeletonema sp. and D. tertioelecta, respectively. Finally, regarding sensitivity, the toxicity sensitivity of Skeletonema sp. was relatively higher than that of D. tertiolecta for the reference toxicant, actual polluted water discharged (ballast water), and other chemicals. This implies that using at least two species of microalgae from different classification groups could help increase the reliability and objectivity of test results in the performance of marine ecotoxicity tests using producers.

• Korean Journal of Environmental Biology
• /
• v.32 no.2
• /
• pp.118-128
• /
• 2014

The growth rate of Skeletonema marinoi-dohrnii complex isolated from Gyeonggi Bay was studied in on axenic batch cultures, under non-nutrient limited condition to determine the growth rate over a wide range of light intensities ($5{\sim}500{\mu}mol\;m^{-2}s^{-1}$) and temperature ($2{\sim}35^{\circ}C$). This species exhibited its maximum specific growth rate of $2.48d^{-1}$ at a combination of $26.1^{\circ}C$ and light intensity of $197{\mu}mol\;m^{-2}s^{-1}$ as associated to optimal conditions of light and temperature. The results supported that S. marinoi-dohrnii complex are more likely to occur in late winter-spring blooms in the western and southern Korea as well as Gyeonggi Bay due to relatively high growth rates ($0.79{\sim}1.61d^{-1}$), considering the effect of temperature on nutrient competition among Skeletonema species. This study might be helpful to improve the precision and reality of a coastal ecosystem model.

• Korean Journal of Environmental Biology
• /
• v.38 no.1
• /
• pp.21-29
• /
• 2020

Morphology of a strain of unspecified Skeletonema species established from Korean coast was examined by light, fluorescence and scanning electron microscopy, and SSU(small subunit) and LSU(large subunit) rDNA of the strain were also sequenced. The specimen was characterized by solitary or short chains, and each cell contained 1-2 chloroplasts. The valve face was slightly convex, and the terminal fultoportula processes (TFPPs) were open and showed narrow distal ends that could be truncated or spiny with claw-like protrusions. The basal part of the TFPPs was tubular and oblique to the cell axis. The intercalary fultoportula processes (IFPPs) were also narrow, completely open, and joined in a 1 : 1 junction. Occasionally, one IFPP was connected with two opposing IFPPs. The morphological features of the specimen were identical to those of Skeletonema pseudocostatum. Molecular phylogeny based on SSU rDNA revealed that the Korean strain is nested within a clade comprising S. pseudocostatum and S. tropicum. However, based on D1-D2 LSU rDNA sequences, a clade including S. pseudocostatum and a Korean strain was separated from the S. tropicum clade. This indicates that the Korean strain can be identified as S. pseudocostatum. This species represents the first record from Korean coastal waters.

• ALGAE
• /
• v.24 no.4
• /
• pp.195-203
• /
• 2009

Most Skeletonema species have been identified under the name of S. costatum. To assess the morphological species diversity in the genus Skeletonema, we surveyed the nine localities in the coastal waters of South Korea. The light microscopy (LM) and scanning electron microscopy (SEM) observations in this study showed that ultrastructural features of genus Skeletonema discriminated among four species: S. dohrnii Sarno & Kooistra, S. marinoi Sarno & Zingone, S. subsalsum (Cleve) Bethge, and S. tropicum Cleve. In S. dohrnii, cell diameters were 3-6 ${\mu}m$ and the pervalvar axes were 13-19 ${\mu}m$. One or two partial chloroplasts were visible in a cell. Cells of S. marinoi were 4-10 ${\mu}m$ and the pervalvar axes were 8-18 ${\mu}m$. Each cell contained one chloroplast. Cells of S. subsalsum which contained 1-2 chloroplasts were 8-13 ${\mu}m$ and the pervalvar axes were 11-20 ${\mu}m$. Cells of S. tropicum were 10-18 ${\mu}m$ and the pervalvar axes were 4-9 ${\mu}m$. 2-4 chloroplasts were seen in each cell. Tip width of fultoportula in S. dohrnii and S. marioni was flared and flat, but that in S. subsalsum and S. tropicum was narrow. Morphological groups among them, S. dohrnii and S. marinoi were the most widely distributed in all seasons, while S. tropicum was only occurred in a summer season.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.6
• /
• pp.805-811
• /
• 1995

Final biomass yields (peak optical density) and growth rates (divisions/day) of seven clones of Skeletonema costatum from Korean coastal waters were measured to understand their intraspecific variations in the light intensity niche component under $25^{\circ}C$ condition. Daily growth rates of 6 of 7 S. costatum, clones were maximum at 6000 lux while that of YS4, a neritic clone, was maximum at 9000 lux. The final biomass yields of 4 of the 7 S. costatum clones were maximum at the lowest light intensity of 2000 lux. Minimum final biomass yields were found at 9000 lux in all the S. costatum clones other than an estuarine clone, HDC9. The intraspecific variations of the mean growth rate and mean final biomass yield under each of the three different light intensity in terms of the coefficient of variation were not greater than 10% in any of the 7 S. costatum clones.

• The Plant Pathology Journal
• /
• v.31 no.2
• /
• pp.186-191
• /
• 2015

Diatoms are a major component of the biological community, serving as the principal primary producers in the food web and sustaining oxygen levels in aquatic environments. Among marine planktonic diatoms, the cosmopolitan Skeletonema costatum is one of the most abundant and widespread species in the world's oceans. Here, we report the basic characteristics of a new diatom-infecting S. costatum virus (ScosV) isolated from Jaran Bay, Korea, in June 2008. ScosV is a polyhedral virus (45-50 nm in diameter) that propagates in the cytoplasm of host cells and causes lysis of S. costatum cultures. The infectivity of ScosV was determined to be strain- rather than species-specific, similar to other algal viruses. The burst size and latent period were roughly estimated at 90-250 infectious units/cell and <48 h, respectively.