• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2004년도 학술대회
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• pp.33-33
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• 2004

• 환경생물
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• 제31권4호
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• pp.295-301
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• 2013

함평만 갯벌에서 2005년부터 2013년까지의 조사를 통해 동정된 저서규조류 중 가장 우점도가 높은 종은 Paralia sulcata였으며 연간 40종에서 77종의 범위로 동정되었다. 조사가 이루어진 8년 동안 출현종의 분석에서 완만하지만 지속적으로 다양도가 감소하는 경향을 나타냈다. 조사시기에 따른 출현종 분포에서는 전 지점에서 5월과 7월에 비교적 다양했고 3월에 종조성이 가장 단순한 것으로 나타났으나, 유의성이 없는 것으로 분석되었다. 표층 퇴적물의 연 평균 엽록소 a 농도는 21~65 mg $m^{-2}$이었으며 2006년 이후 지속적으로 감소하는 경향을 나타내다가 2011년에는 세 지점 모두에서 일시 증가한 후 다시 감소하는 것으로 나타났다. 계절 분포에서는 봄철에 가장 높고 여름에서 가을로 접어드는 시점에 가장 낮은 것으로 나타났다. 단위면적당 출현 개체수도 세 지점 모두에서 점진적으로 감소하는 경향을 나타냈고, 생물량도 감소하는 경향을 보여주었다. 온도에 따른 저서규조류 출현종수 $Y=-0.0208X^2+0.5264X+19.529(r^2=0.0269)$의 식으로 표현되어 최고의 종 다양도는 $15^{\circ}C$에서 23.1종인 것으로 나타났고, 저서규조류 생물량 $Y=-0.9181X^2+27.011X+310.07(r^2=0.0797)$의 식으로 표현되어 최고의 생물량은 $15^{\circ}C$에서 502.38 ${\mu}m^3cm^{-2}$인 것으로 나타났다.

• 한국지구과학회지
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• 제42권6호
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• pp.677-687
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• 2021

로스해의 Iselin Bank 인근에서 채취한 RS15-GC41코어로부터 규조를 분석한 결과 총 24속 35종의 규조를 감정하였으며, 규조 개체수 농도는 0.2-28.6×10⁶/g 범위에 해당하였다. 규조 군집 조성에 의해 4개의 규조 군집대를 설정하였으며 규조 군집의 변화는 거의 10만년을 주기로 변화 하였다. Marine Isotope Stages 1-11 시기에 RS15-GC41이 퇴적되는 동안 간빙기(Interglacial)에는 open ocean을 지시하는 Rhizosolenia styliformis, Fragilariopsis kerguelensis와 Thalassionema nitzschioides등이 풍부하게 산출되며, 빙기(Glacial)에는 sea-ice종인 Actinocyclus actinocyclus의 산출이 풍부하게 나타난다. MIS 7, 9와 11의 간빙기 동안 MIS 1, 3과 5 시기보다 sea-ice의 분포가 더 넓고 지속 기간이 더 오래 계속되었음을 알 수 있다. Paralia sulcata는 이 시기(MIS 7, 9와 11) 동안 해류에 의한 ice-rafted debris의 유입과 함께 연안지역으로부터 재이동 되었음을 뒷받침 해 준다.

• Journal of Ecology and Environment
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• 제36권4호
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• pp.371-390
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• 2013

Remarkable diversity of diatom taxa occurs in intertidal sand-flats of the Nakdong River estuary, one of the most dynamic and productive ecosystem in Korea. Benthic diatoms were collected from the sandy sediments to clarify the taxonomic accounts and distribution of the old genus Navicula, i.e., the naviculoid flora. Total 92 taxa belonging to Navicula sensu stricto and 22 genera separated from Navicula sensu lato are reported with brief descriptions and micrographs, and many species remain unidentified. The genera are ranked by the number of diatom species: Navicula of 33 species and varieties, Fallacia of 17 species, Placoneis of five species, Fogedia and Parlibellus of four species, Austariella, Hippodonta and Petroneis of three species, Cosmioneis, Diadesmis, Luticola, Moreneis and Sellaphora of two species and variety, Berkeleya, Chamaepinnularia, Cocconeiopsis, Diademoides, Dickieia, Eolimna, Geissleria, Haslea, Lyrella and Mayamaea of one species. Through 32 samplings of the 12 areas, the important species were identified Navicula perminuta, N. gregaria, N. torneensis, Fallacia cunoniae, F. litoricola, F. subforcipata, F. tenera. The naviculoid diatoms constitute an average of 27% (range: minimum to maximum, 5-75%), of the benthic diatom assemblages. The diatom assemblages are characterized by the colonizing of a few dominant or frequent species and many occasional or rare species. The dominant species were observed to fluctuate with sampling site and time. Among the reported naviculoid diatoms, 46 taxa are newly reported in Korea.

• 한국물환경학회지
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• 제30권6호
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• pp.665-672
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• 2014

Elemental cellular stoichiometry of natural phytoplankton communities was examined in six large dam reservoirs in the Han River system. Carbon (C) and nitrogen (N) contents of the phytoplankton-dominated seston from Lake Soyang was higher than that from other lakes. Phosphorus (P) content showed slight variations among six lakes in the range of $0.04{\sim}0.18{\mu}mol$ P mg $DW^{-1}$. The phosphorus concentrations of lake water showed obvious positive relationship with P and C contents of the phytoplankton-dominated seston. In all six lakes, N:P ratios and C:P ratios in the phytoplankton-dominated seston were more than 23 and 133 respectively, indicating the phytoplankton communities in six lakes have been exposed in phosphorus limited condition. The relative abundance of diatoms showed significant negative correlation with C, N, P contents of the phytoplankton-dominated seston and that of cyanobacteria showed significant positive correlation. Elemental stoichiometry of diatoms-dominated seston showed distinctive less content than that of cyanobacteria-dominated seston. The cellular N:P ratios of diatoms- and cyanobacteria-dominated seston indicate that both main classes of phytoplankton in six lakes are in phosphorus deficiency. Elemental stoichiometry of the phytoplankton-dominated seston in this study could be used for the further ecological stoichiometric studies in six lakes.

• Preventive Nutrition and Food Science
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• 제13권3호
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• pp.166-175
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• 2008

In this study, we focused on natural water-soluble antioxidants from the Jeju benthic diatoms, Achnanthes longipes, Navicula sp. and Amphora coffeaeformis. They were prepared by enzymatic digestion using five carbohydrases (Viscozyme, Celluclast, AMG, Termamyl and Ultraflo) and five proteases (Protamex, Kojizyme, Neutrase, Flavourzyme and Alcalase) and their potential antioxidant activity was assessed. Among the enzymatic digests, Neutrase digest from A. coffeaeformis exhibited the highest effect in DPPH radical scavenging. Flavourzyme (48.7%), Viscozyme (47.4%) and Celluclast (45.7%) digests from Navicula sp. exhibited higher $O^{{\cdot}-}_2$ radical scavenging activity. Viscozyme digest from A. coffeaeformis (45.9%) possessed the highest effects in hydroxyl radical scavenging. Termamyl (89.3%) and Protamex (88.8%) digests from A. coffeaeformis had strong metal chelating activity. Lipid peroxidation was significantly inhibited in Termamyl and Kojizyme digests from A. longipes, AMG and Termamyl digests from Navicula sp. and Kojizyme digest from A. coffeaeformisi. These data suggest that enzymatic digests of the Jeju benthic diatoms might be valuable sources of antioxidant which can be applied in food and pharmaceutical industry.

• Journal of Species Research
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• 제10권3호
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• pp.237-245
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• 2021

Tidal flats are well developed in and around the Yellow Sea of Northeast Asia, and benthic diatoms are the most important primary producers in corresponding habitats. In the present study, the taxonomy and distribution of small negligible diatom species from Northeast Asian tidal flats are investigated for better understanding of the diversity of Korean marine benthic diatoms. The presence of Plagiogrammopsis minima and Diploneis aestuarii, which may have been ignored and/or misidentified due to their small size, were identified by both means of light microscopy (LM) and scanning electron microscopy (SEM). Plagiogrammopsis minima has never been reported from Korea before the present study, while Diploneis aestuarii was only once mentioned without any photographic information. Accordingly, we provide the morphological characteristics of the two species in detail with LM and SEM observation. Information on the regional distribution of the two species is also provided. Results of the present study contribute to the better understanding of the biodiversity of the Korean marine benthic diatoms.

• Ocean and Polar Research
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• 제27권3호
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• pp.341-349
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• 2005

Temporal variation of the natural planktonic community in the Southern Sea of Korea was investigated by using low floating enclosed bags (3.2m deep and 2,500 liter) in order to understand the effect of enriched nitrate on the planktonic community in the spring (March-April) of 2002. Prior to beginning the incubation, the bags were placed in two different concentrations of nitrate, which consisted of control (ambient water) and experimental mesocosms (final concentration of $12{\mu}M$). The nitrate concentration in the experimental mesocosms remained significantly higher than those in control mesocosms throughout the study period (ANOYA, p<0.001). Following the addition of nitrate, abundance and chi-a concentration of phytoplankton peaked on Day 1, when diatoms established the peak in the experimental mesocosms. Diatoms consisted mainly of Thalasxiosira decipiens, Pseudo-nitzschia pungem, Leptocylindrus danicu, Thalassionema nitzschioides, Chaetoceros pseudocrinitus and Actinoptychus senariu. However, the peak did not lead to the difference in abundance and composition of phytoplankton between control and experimental mesocosms during the study period. The dinoflagellates began to increase soon after the diatoms decreased in all mesocosms. Copepods, as a dominant group in the rnosozooplankton community, showed no immediate peak in relation to the nitrate addition, but only their own developmental process from the eggs to adult stage during the study period. The bottom-up control from enriched nitrate via phytoplankton to adult copepods was not distinguished in terms of the abundance of the planktonic community. This might stem from the relatively low nitrate availability of phytoplankton at no N-limited seawater and the weak coupling between rapidly sunken diatoms and copepods through the water column.

• ALGAE
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• 제24권1호
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• pp.47-55
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• 2009

Recently, interest in plant-derived food additives has developed natural antioxidants, in order to alternate syn-thetic antioxidants with several disadvantages. In the present study, different organic fractions from solvent parti-tions of 80% methanol extract from Jeju benthic diatoms, Achnanthes longipes, Navicula sp. and Amphora coffeaeformis was assessed for their potential antioxidant effects. Among the solvent fractions tested, n-hexane (80.4%) and 80% methanol extract (76.6%) from A. longipes, chloroform (63.2%) from Navicula sp. and n-hexane (67.4%) from A. cof-feaeformis were effective in DPPH free radical scavenging. Fractions of chloroform (53.4%) and n-hexane (53.1%) from A. longipes exhibited higher activities on $H_2O_2$ scavengin. Fraction of n-Hexane from A. longipes exhibited the highest hydroxyl radical scavenging activity and NO. scavenging activity (56.5% and 75.6%, respectively). Aqueous residue from A. coffeaeformis (75.6%) showed the highest metal chelating effect. chloroform and ethyl acetate frac-tion of all the diatoms exhibited significant antioxidant activities in lipid peroxidation inhibitory activity. In particu-lar, both chloroform and the ethyl ecetate fraction from A. longipes and A. coffeaeformis exhibited lipid peroxidation inhibitory activity significantly higher than that of $\alpha$- tocopherol. These data suggest that the Jeju benthic diatoms tested are rich in hydrophilic and hydrophobic antioxidative compounds with different antioxidative properties that can be applied in food industry.

• 한국수산과학회지
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• 제36권6호
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• pp.591-595
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• 2003

Settlement of larvae, growth, and survival of juvenile abalone (Haliotis discus hannai) were examined after feding of 5 species of benthic diatoms (Cocconeis suctellum, Navicula sp Nitzschia longissima Bacillavia paxillifera, Licmophora flabellata). All of the benthic diatoms were isolated from natural populations on plastic plates for the abalone. The settlement of larvae, shell growth, and survival rate of juvenile abalone varied by diatoms species. The highest settlement rate of larvae was $43.1\%$ with the Cocconeis suctellum diet. Daliy growth rate reached a maximum at 64.1 ${\mu}m/day$ with the Navicula sp. diet and a minimum at 22.4 ${\mu}m/day$ with the Licmophora flabellata diet. Survival rate of the juvenile abalone was highest at $62.0\%$ with the Navicula sp., Cocconeis suctellum , and Nitzschia longissima diets. Survival rate of the Juvenile abalone was significantly higher than the control group with mixed diatom population diets (P<0.05). Therefore, diatom . species composition in diets can be a controling factor for the settlement, growth, and survival rates of Juvenile abalone.