• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.687-692
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• 2010

The mass cultivation of Ecklonia cava Kjellman was studied as a potential biomass source for the extract industry in Korea. Experiments were conducted to investigate the optimal conditions for artificial seed production and mass cultivation of this species. Maximum growth and young thalli development in the nursery culture area occurred at 2 m depth, whereas maximum growth of thalli in the main culture area occurred at 1 m depth. Production of E. cava was between 2.6 and 3.6 kg wet wt. $m^{-1}$ after depth control and removal of fouling organism, etc. The relationship between optimal water depth for culture and underwater irradiance during the E. cava cultivation was calculated as: y = -0.718x + 8.042 ($r^2$=0.976). The growth rates achieved in this trial indicate that E. cava cultures could produce and supply sufficient biomass.

• ALGAE
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• v.19 no.2
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• pp.123-127
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• 2004

A more rapid and efficient method to extract RNA from Ecklonia cava Kjellman (Laminariales, Phaeophyceae) was introduced in this study. Each step of the procedure was evaluated and the optimal concentration of each chemical in the lysis solution was determined. Tissue pulverization with PVPP and β-mercaptoethanol in the lysis solution were not essential for RNA extraction of this species. The highest yield and purity of E. cava RNA were obtained by the lysis solution containing 1% CTAB, 1 M NaCl, 0.7% PVP, 10mM EDTA and 100mM Tris-Cl (pH 9.0). Approximately 8μg of RNA was obtained from 200 mg of ground tissue. The ratios of the absorbance at 260 nm and 280 nm were from 1.6 to 1.8 and those of at 230 nm and 260 nm were from 1.8 to 2.0. The extracted RNAs obtained in this study turned out to have a sufficient quality for cDNA synthesis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.704-711
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• 2015

We examined the effects of temperature and light intensity on gametophyte growth of Ecklonia cava Kjellman. The growth of female and male gametophytes was investigated before maturation. Gametophytes prepared from Munseom, Jeju, Korea in October 2014 were separated by sex and maintained under the following conditions: 15℃, 20 μmol·m^-2·s^-1, and a 12-h/12-h light/dark cycle. The experiments were conducted at five temperatures (10, 15, 20, 25, and 30℃) and three light intensities (5, 20, and 40 μmol·m^-2·s^-1). Daily growth rates were estimated by the increase in filamentous frond area. The optimal growth conditions for female gametophytes were 20℃ and 40 μmol·m^-2·s^-1; the optimal conditions for male gametophytes were 15℃ and 20 μmol·m^-2·s^-1. The relative growth rates (RGR) of female and male gametophytes decreased at 25℃ and 30℃, respectively. At 30℃, RGRs of gametophytes decreased by approximately 1.0% day^-1. In addition, RGRs of male gametophytes were higher than those of female gametophytes. These results indicate that female gametophytes were more sensitive to temperature and light intensity than male gametophytes. Moreover, these results suggest that E. cava growth rates could decrease as a result of global warming.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.5
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• pp.381-388
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• 2008

Induction of regeneration and maturation for the free-living gametophytes of Ecklonia cava Kjellman was conducted under various temperature, irradiance and photoperiod conditions. Culture conditions for female or male gametophyte fragments were 4 temperature (5, 10, 15 and $20^{\circ}C$), 4 irradiance (5, 10, 20 and $40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and 3 photoperiod (14:10, 12:12 and 10:14 h L:D). Female and male gametophyte fragments were maintained in active regeneration without reaching sexual maturity under $5{\sim}10^{\circ}C$, $5{\sim}10{\mu}mol{\cdot}m-2{\cdot}s-1$, 12:12h or 10:14h (L:D) and $15-20^{\circ}C$, $20-40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 14:10h (L:D), respectively. Sexual maturation of female and male gametophytes facilitated under $15^{\circ}C$, $20-40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 14:10h (L:D) and $5-10^{\circ}C$, $5-10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 10:14h (L:D), respectively. These results provide basic informations to control the regeneration or maturation of the free-living gametophytes for artificial seed production of E. cava.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.64-70
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• 2011

Nitrate reductase (NR) is activated by nitrogen sources (${NO_3}^-$ and ${NH_4}^+$) and irradiance. This study investigated the effects of these factors on the NR activity of Ulva pertusa (Chlorophyta) and Ecklonia cava (Phaeophyta). In addition, the ammonium (${NH_4}^+$) and nitrate (${NO_3}^-$) uptake rates of the two species were examined. U. pertusa took up most of the ${NO_3}^-$ and ${NH_4}^+$ in the medium during a 3hour incubation, while E. cava had a relatively high uptake rate after 3 hours. The NR activities of the two species were affected by the nitrogen source and irradiance and were highest when they were exposed to ${NO_3}^-$-rich medium and high irradiance. However, the patterns of NR activity differed between the two species. In ${NO_3}^-$-rich medium and high irradiance, U. pertusa achieved the highest NR activity ($2.01{\pm}0.07\;{\mu}mol$ ${NO_2}^-$ $g^{-1}$ DW $h^{-1}$) within the first 3 hours and then this activity decreased drastically. By contrast, the NR activity of E. cava ($0.36{\pm}0.04\;{\mu}mol$ ${NO_2}^-$ $g^{-1}$ DW $h^{-1}$) was constant for 12 hours. When exposed to darkness, the NR activity of U. pertusa decreased dramatically, while that of E. cava increased gradually for 12 hours. Therefore, E. cava is able to maintain NR activity during the dark because of its adequate carbohydrate reserves and substrate.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.347-352
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• 2013

Outdoor cultivation experiment was conducted with artificial seeds using free-living gametophytes and zoospores of Ecklonia cava to develop FLG (free-living gametophyte) seeding technique. Growth of thalli between FLG and zoospore seeding groups was compared monthly from May to October 2009 at culture farm in Wando, Korea. In September 2009, thalli in the FLG seeding experimental group were $35.9{\pm}0.8$ cm in length, $24.1{\pm}2.62$ g in weight, $2.32{\pm}0.26$ kg $m^{-1}$ in biomass and $22.0{\pm}2.8$ individuals $m^{-1}$ in density. There were no significant differences in length, weight, biomass and density between FLG and zoospore seeding group. Therefore, the FLG seeding technique could replace the zoospore seeding method which would eventually contribute in restoration and conservation of natural resources.

• Korean Journal of Veterinary Research
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• v.56 no.4
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• pp.255-260
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• 2016

The Ecklonia cava Kjellman by-product (ECBP) as a feed additive was evaluated in improvement of productivity and immune enhancement against Salmonella Gallinarum (SG). Lohmann Brown chickens proved SG-free were randomly divided into 3 groups of 8 chickens each. Chickens were fed with the experimental diet treatment: T0, Non treatment-commercial feed; T1, commercial feed with 0.5% ECBP; T2, commercial feed with 0.1% Lactobacillus plantarum. In this study, we evaluated the effect of T1 and T2 groups on the body weight and protective efficacy against SG in chickens. The results demonstrated that treatment of T1 group as a feed additive affected significantly body weight gaining in chickens. In addition, T1 group showed a significant different colonization of SG when compared to T2 and T0 groups. We also studied that serum IgG and $interferon-{\gamma}$ levels were significantly different compared with other treatment groups. Therefore, we suggest that ECBP can be used as a good candidate of feed additives in chicken industry.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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• pp.523-526
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• 2009

Biodegradable polybutylene succinate (BPS) multifilament were designed to degrade upon disposal by the action of afforestration of Ecklonia cava. Matured thalli of E. cava were collected at Jeju for zoospore collection and the substrate for zoospores were BPS multifilament (12 mm, 500 Td/96). The materials were made as nets of $1\;m^2$ with a cross stripes of 10 cm. The unit biodegradable nets bearing germlings of E. cava was moved into Wando where the place is conducting intensive seaweed cultivation in Korea for 5 months of nursery culture until they grew to 10 cm in length after which the nets were transplanted into the sea bed at Jeju at a depth of 12 m and the algal growth was monitored from May 2007 to December 2008. This is the first instance of using the BPS materials for seaweed afforestation to avoid any environmental problems.

• ALGAE
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• v.30 no.2
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• pp.89-101
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• 2015

Ecklonia cava Kjellman is a common kelp found in shallow subtidal in warm-temperate waters in the northwest Pacific Ocean. This species has shown substantial morphological variation along with subsistence in different locations and local environments. We quantified the magnitude of morphological variation of E. cava from six populations along ~700 km of coastline from Jeju Island to Dokdo in Korea. In addition, we examined genetic distance among the populations using random amplified polymorphic DNA (RAPD) analysis. Most morphological characteristics investigated were significantly different among locations. Multivariate analyses indicated two phenetically distinct groups (nearshore, sheltered vs. offshore, exposed), indicating wave exposure with turbidity are presumably major factors for the separation. With RAPD data, results of Nei's diversity (H) and AMOVA showed considerable variations in within- and between-populations. Pairwise ${\Phi}_{ST}$ and $N_m$ values indicated moderate gene flow between the six locations. Results of Nei's analysis revealed three genetically distinct groups, not consistent with the morphological groupings, indicating that a time gap may exist between morphological and genetic variations. This study also suggests dispersal distance of this kelp may be longer than what is commonly thought and genetic similarity in the populations was largely reflected by the direction of ocean current rather than just geographical distance.

• ALGAE
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• v.28 no.4
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• pp.365-369
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• 2013

The objective of this study was to determine the optimal blade size and timing to transplant seed-stock of Ecklonia cava Kjellman onto the reef structure. We used the modified artificial stepped reef structure. A total of 14 units (3.0 m length ${\times}$ 3.5 m width ${\times}$ 1.1 m height) were deployed 7-8 m deep under the water to examine the optimal blade size and timing to transplant seed-stock of E. cava onto the structures. Sporophytes of E. cava <1 cm in length were all died within 1 month of transplantation. The blades of 5-10 cm in length which were transplanted in March 2007 survived and grew well on the artificial reefs. Growth rates of 5-10 cm size class were higher than those of longer blade sporophytes (20-30 cm size class, transplanted in April) while the survival rates showed no difference between the classes of blade size. Both classes of 5-10 and 20-30 cm in length grew until July, and a reduction in size had occurred in September. These results indicate the importance of the blade size of E. cava and timing for successful transplantation of the seaweed on artificial reef structures.