• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.4
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• pp.301-304
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• 2008

For bioremediation of the benthic layer uptake kinetics of phosphate by microphytobenthos Nitzschia sp.(JFH200406) were investigated. A short-term phosphate uptake revealed that the maximum uptake rate(${\rho}_{max}$) and half-saturation constant($K_s$) were 0.132 pmol/cell/hr and 502.6 ${\mu}M$, respectively. The maximum specific uptake rate calculated between ${\rho}_{max}$ and the phosphorus cell quota($Q_p$), calculated from Strathmann equation, was 14.4/day. The values of these parameters indicate that Nitzschia sp. accommodates well to surroundings of high phosphate, and can uptake over 14-times more than the phosphorus cell quota. Thus, microphytobenthos Nitzschia sp. may be a useful species for bioremediation of the benthic layer.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.2
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• pp.130-137
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• 2011

To improve sediment quality in eutrophic coastal areas using benthic microalgae, we examined the effects of temperature and salinity on the growth of benthic microalgae Achnanthes sp., Amphora sp., Navicula sp. and Nitzschia sp. isolated from Sujeong Bay, Korea, using batch cultures. The maximum growth rates were obtained under the combined temperature and salinity conditions of $25^{\circ}C$ and 25 psu for Achnanthes sp. (0.60 /day), $15^{\circ}C$ and 25 psu for Amphora sp. (0.56 /day), $20^{\circ}C$ and 30 psu for Navicula sp. (0.53 /day), $20^{\circ}C$ and 25 psu for Nitzschia sp. (0.48 /day). Considering these results of temperature and salinity conditions required for optimum growth (${\geq}$ 70% of maximum specific growth rate), Amphora sp. Navicula sp. and Nitzschia sp. were characterized as eurythermal and euryhaline species, while Achnanthes sp., which exhibited extremely low survival at low temperature. In conclusion, Amphora sp., Navicula sp. and Nitzschia sp. may be useful species for phytoremediation, to control eutrophication and hypoxic water and thus improve environmental conditions of polluted coastal areas.

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

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.1-7
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• 2010

We were successfully reared young marine ornamental larva fish in a unique process of microalgae blooming culture tank. The marine fish larva was grown and survived in this method. Generally, we called this method as natural mixed culture. Observed planktonic microalgae were 34 species with 19 diatoms (Detonula pumila, Nitzschia sp., Fragilaria oceanica, Chaetoceros curvisetus, Stephanodiscus sp., Chaetoceros decipies, Chaetoceros sp., Thalassiosira rotula, Eucampia zodiacus, Diploneis splendica, Nitzschia longissima, Surirella cuneata, Asterionella glacialis, Nitzschia spp., Chaetoceros debile, Thalassionema nitzschioides, Nitzschia closterium, Skeletonema costatum and Licmophora sp.), 14 flagellates (Euglena, sp., Gonyaulax sp., Pyramimonas sp., Protoperidinium sp., Eutreptia sp., Parapedinella sp., unidentified micrc-flagellate, Gyrodinium sp., Scrippsiell trochoidea, Gymnodinium sanguineum, Chrysochromulina sp., Gymnodinium sp., Prorocentrum triestinum and Micromonas sp.) and 1 ciliate (Mesodinium rubrum) in this culture tank. Dominant microalgae were Chrysochromulina sp. during the larval rearing periods. Blooming condition maintained continuously and stably from 10 to 60 days in this microcosm.

• ALGAE
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• v.22 no.4
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• pp.319-323
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• 2007

This study was conducted with using chlorophyll a fluorescence (indicated as photosynthetic activity) to examine the toxic effect of 96 h exposure of heavy metals and herbicides on the benthic diatom Nitzschia sp. which was isolated from pristine sediment in Pamquat Harbour, Nova Scotia, Canada. Samples of benthic diatom were exposed to 0, 0.01, 0.1 and 1 mg L–1 of copper, 0, 1, 10 and 100 mg L–1 of chrome (VI), 0, 2.45, 24.5 and 245 mg L–1 of paraquat dichloride, and 0, 4.37, 43.7 and 437 mg L–1 of alachlor during 96 hours. The effective quantum yield of photochemistry (ΔF/Fm’) was evaluated by subjecting light acclimated samples to saturating pulses of light using a pulse amplitude modulated (PAM) fluorometer. The impact of heavy metals on Nitzschia sp. photosynthesis was not severe in < 1 mg L–1 but in the high concentrations (> 1 mg L–1) clearly increased toxic stress during 96 h. Herbicides had a limited impact during the exposure period but clearly increased stress on the benthic diatom with increasing concentrations. Acute response of Nitzschia sp. to selected heavy metals and herbicides was characterized, and the capacity of a benthic diatom to tolerate and recover from toxic stress was assessed.

• Journal of Environmental Science International
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• v.21 no.1
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• pp.105-111
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• 2012

The effects of substrate size on the growth of microphytobenthos Achnanthes sp., Amphora sp., Navicula sp. and Nitzschia sp. were examined using glass beads in order for phytoremediation in the benthic layer of coastal waters. The glass beads used in this study were 0.09~0.15 mm (G.B 1), 0.25~0.50 mm (G.B 2), 0.75~1.00 mm (G.B 3) and 1.25~1.65 mm (G.B 4). No addition of glass bead used as control. The specific growth rate and maximum cell density of four microphytobenthos species were increasing with decreasing size of glass beads. Moreover, the control experiment without added attachment substrates showed the lowest specific growth rate and maximum cell density. Therefore, the suitable attachment substrates for mass culture of microphytobenthos seems to be important in order for phytoremediation using microphytobenthos.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.2
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• pp.91-95
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• 2009

To understand the effect of attachment substrate on the growth of benthic microalgae, we experimentally investigated the growth of benthic microalgae Nitzschia sp. (Jinhae Bay strain) with additions of glass beads in different sizes. The glass beads used in this study are 0.09-0.15 mm (G1), 0.25-0.50 mm (G2), 0.75-1.00 mm (G3) and 1.25-1.65 mm (G4). No addition of glass beads used as controls. Highest specific growth rate (0.37/day) and maximum cell density ($9,232{\pm}840$ cells/mL) of Nitzschia sp. showed at the smallest glass beads (G1), and the specific growth rate and maximum cell density were decreasing with increasing size of glass beads (specific growth rate and maximum cell density of G4 was 0.24/day and $6,397{\pm}524$ cells/mL, respectively). Moreover, specific growth rate of the control experiment (0.23/day) was significantly lower than their of G1 to G3 experiment. The results indicated that the attachment substrate for benthic microalgae as Nitzschia sp. is important factor which affecting the growth rate as well as cell density. Therefore, the physiological experiment of benthic microalgae seems to be necessary to preliminary experiment, which is addition or not of the attachment suitable substrate and the grain size for the target species of benthic microalgae.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.4
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• pp.205-212
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• 2009

To suggest possible to bioremediation by benthic microalgae Nitzschia sp. isolated from the Jinhae Bay, the studies investigated the effects o flight quality and quantity on the growth of Nitzschia sp. and its growth kinetics for phosphate investigated. The Nitzschia sp. was cultured under blue (450 nm), yellow (590 nm) and red wavelength (650 nm) using light emitting diode (LED) and mixed wavelengths using a fluorescent lamp. The maximum specific growth rate showed the Nitzschia sp. under blue wavelength, although photoinhibition was observed above $100\;{\mu}mol\;m^{-2}\;s^{-1}$. Mixed wavelengths were also observed by decreasing the maximum cell density from high irradiances (>$100\;{\mu}mol$ photons $m^{-2}\;s^{-1}$). The compensation photon flux density ($I_0$) calculated from the mixed wavelengths equated to a depth of 4-10 m in Jinhae Bay, and was lower in the summer season than the depth due to suspended matter (ca. 4 m). Thus, the suitable depth for maximum growth of Nitzschia sp. might be extremely limited. In the growth kinetics for phosphate, half-saturation constant ($K_s$) was similar among different wavelengths, although the maximum growth rate was varied among different wavelengths. Because the $K_s$ was high than that of the phytoplankton, Nitzschia sp. might have adapted to the high nutrient concentrations, and have effective nutrient storage in the cell quota. Thus, Nitzschia sp. may be a useful species for bioremediation of the benthic layer in polluted inner bays by means of irradiated specific wavelength as blue.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.2
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• pp.93-101
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• 2007

In order for bioremediate the benthic layer in polluted inner Bay, the effects of irradiance and wave-length irradiated from light emission diode (LED) on the growth of benthic diatom Nitzschia sp. (Hakozaki Bay strain of Japan) were investigated. The Nitzschia sp. was cultured under blue LED (450 nm), yellow LED (590 nm), red LED (650 nm) and fluorescent lamp (mixed wavelengths). At $25^{\circ}C$ and 30 psu, the growth of Nitzschia sp. showed its peak at $20\;{\mu}mol\;m^{-2}\;s^{-1}$ (blue LED) and $40\;{\mu}mol\;m^{-2}\;s^{-1}$ (fluorescent lamp), and was inhibited at the irradiance higher than that irradiance. Nitzschia sp. in yellow LED and red LED is fitted by a rectangular hyperbolic curve because no photoinhibition was observed under maximum irradiance used in this study. The irradiance-growth curves were described as ${\mu}=-0.46{\exp}(1-I/6.32)+0.46-0.00043I,\;(r^2=0.98)$ under blue LED, ${\mu}=0.42(I+7.87)/(I+58.9),\;(r^2=0.99)$ under yellow LED, ${\mu}=0.39(I+3.39)/(I+21.6),\;(r^2=0.94)$ under red LED, ${\mu}=-0.38{\exp}(1-I/7.23)+0.38-0.00016I,\;(r^2=0.96)$ under fluorescent lamp. Maximum specific growth rate of blue LED, yellow LED, red LED and fluorescent lamp was $0.44\;day^{-1},\;0.42\;day^{-1},\;0.39\;day^{-1}$ and $0.37\;day^{-1}$, respectively. The absorption coefficient ($a_{ph}$) of Nitzschia sp. was similar under all the wavelengths (400 nm-700 nm), although maximum $a_{ph}$ was $0.0224\;m^2\;mg\;chi.\;{\alpha}^{-1}$ in 472 nm and $0.0179\;m^2\;mg\;chi.\;{\alpha}^{-1}$) in 663 nm. The results may indicate the possibility of environmental improvement around the benthic layer in polluted coastal area because microphytobenthos growth is stimulated by means of irradiated blue LED at the benthic boundary layer during both autumn and winter, and yellow LED, which might have been suppressed growth of harmful algae, at the layer during both spring and summer.

• 한국해양학회지
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• v.30 no.3
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• pp.163-169
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• 1995

A total of 190 phytoplankton taxa was identified in southern waters of the East Sea of Korea in May 1988, July 1989 and November 1991. Leptocylindrus danicus, Nitzschia pungens and Bacteriastrum delicatulum were the dominant species in spring. In summer, Skeletonema costatum was dominant all around the study area but Chaetoceros socialis and Rhizosolenia alata f. gracillima were locally dominant. On the other hand, the dominant species in autumn shifted to Chaeotoceros socialis, Nitzschia delicatissima, Nitzschia sp. and Gymnodinium sp. The average species diversities of the phytoplankton community were low in spring, summer and autumn, being 1.24, 1.69 and 2.12 respectively. The result of cluster analysis in summer suggested that the surface water of this study area could be divided into three phytohydrographic regions which consisted of the oceanic water region affected by Tsushima current, the east Korean neritic water region and the proper water region adjacent to Ulleung island. Compared with the surface phytohydrographic regions, one more region might be recognized at the 40m depth waters. It was appeared in the middle of study area and seemed to be affected by both Tsushima current and water mass of 10$^{\circ}C$ located deeper than 50m.