• Journal of Life Science
• /
• v.10 no.5
• /
• pp.447-455
• /
• 2000

A eight weeks feeding experiment was conducted to investigate the effects of different dietary dimethyl-$\beta$-propiothetin (DMPT) levels on growth and chemical components in red sea bream (Pagrus major). The content of DMPT extracted from Ulva pertusa by auroclaving was 32.5mg%. Body weight gain, feed efficiency and feed intake were significantly increased with dietary DMPT level. After eight weeks of feeding trial, moisture content decreased with supplemented DMPT level, while crude protein and lipid contents increased with dietary DMPT level. Amino acid contents of muscle was elevated in the DMPT added groups compared to control group. Amino acid composition of muscle in fish fed the diets supplemented DMPT was not different to that of control group. Fatty acid contents of muscle in fish increased with dietary DMPT level.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.5
• /
• pp.371-380
• /
• 2008

This study elucidated the floral composition of marine algae and community structure at Hallyeo-haesang National Park, on the southern coast of Korea. In all, 89 species, comprising 10 green, 30 brown and 49 red algae, were identified. The dominant species in terms of importance value were Ulva pertusa, Colpomenia sinuosa, Undaria pinnatifida, Padina arborescens, Hizikia fusiformis, Sargassum sagamianum and Amphiroa dilatata. The vertical distribution of marine vegetation was characterized by Enteromorpha linza - Ulva pertusa - Gelidium divaricatum in the upper intertidal zone, Hizikia fusiformis - Sargassum thunbergii in the middle intertidal zone, and Amphiroa spp. - Hildenbrandtia rubra - Corallina pilulifera in the lower intertidal zone. Functional form group analysis showed that coarsely branched forms comprised 50.3% of the algal community, whereas thick leathery forms, sheet forms and filamentous forms comprised 11.9-13.1%. R/P, C/P and (R+C)/P values were 1.91, 0.74 and 2.64, respectively. A cluster analysis of species occurrence suggested that the number of marine algal species differed greatly among the sampling sites.

• Journal of the korean society of oceanography
• /
• v.31 no.1
• /
• pp.1-6
• /
• 1996

Salinity ecotypes in Ulva pertusa Kjellman were examined for the growth responses of the three isolates taken from different salinity regimes. All isolates showed a broad salinity tolerance, but growth patterns were correlated with the salinity regime of their original habitat. The germlings from Anin exhibited optimum growth at the native salinity of 32%. The germlings from Yongyon which had hypersaline habitats were tolerable to high salinity, i.e. growth rates peaked at 40%, whereas those from Samgando which had low salinities achieved maximum growth rate at 24\%. The germlings of inter-isolate cross demonstrated intermediate growth response between that of their respective parents. Our data also clearly indicated intraspecific differences among the three isolates, which was interpreted as development of different physiological ecotypes. We conclude that U. pertusa may consist of several ecotypes, each of which has some capacity for physiological adaptation to salinity variations.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2002.05a
• /
• pp.199-200
• /
• 2002

• Proceedings of the Korean Society of Life Science Conference
• /
• 2003.10a
• /
• pp.124-124
• /
• 2003

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.47 no.3
• /
• pp.274-282
• /
• 2014

We examined seasonal variation in the structure of marine macroalgal communities at five sites around the Byeonsan Peninsula, Korea, from January to October 2011. Sixty eight species were identified, including 11 green, 17 brown and 40 red algae. Species richness was highest at Gyeokpo (51 species) followed by Sambal (47), Gosapo (34), Byeonsan (33), and Habgoo (18). Seaweed biomass ranged from 12.98 to 145.33 g dry $wt/m^2$, with maximum and minimum biomasses at Gyeokpo and Habgoo, respectively. Sargassum thunbergii was the representative alga species occupying 47.89% of the total biomass. The dominant seaweeds were S. thunbergii, Corallina pilulifera, Ulva spp, Gracilaria vermiculophylla, and Carpopeltis affinis. No distinctive vertical distribution of seaweeds was found because S. thunbergii, Ulva spp, and G. vermiculophylla were all distributed from high to low shore. Community indices were as follows: dominance index (DI), 0.44-0.61; richness index (R), 6.27-10.35; evenness index (J'), 0.38-0.59; and diversity index (H'), 1.48-1.71. Gyeokpo had the most biomass and highest species richness, and the lowest percentage of Ulva species. However, species richness declined at Gyeokpo, from 78 to 51 species within 10 years, implying that eutrophication and sedimentation from Mankyeong and Dongjin rivers have reduced the stability of seaweed communities.

• Journal of Aquaculture
• /
• v.11 no.1
• /
• pp.31-38
• /
• 1998

A 20-week growth trial was conducted in flow-through aquarium system to investigate the effects of supplemental macroalgae and spirulina in the diets on growth and body cmposition in juvenile abalone (Haliotis discus hannai). Four replicate groups of the abalone averaging 65mg were fed one of ten isonitrogenous (34%) and isolipidic (7.5%) diets containing 8.1% Ulva, 7.5% Undaria, 11% Laminara, 11% Sargassum, spirulina (5, 10 and 15%), or dried Undaria powder (10 and 20%). In addition, these formulated diets were compared with natural food(dried Undaria). Survival rate of abalone were not significantly affected by the different dietary macoralgae sources, spirulina or dried Undaria powder levels (P>0.05). Weight gain and soft body weight of abalone fed the diet containing Sargassum was significantly higher (P<0.05) than those of abalone fed the diets containing Laminaria, 20% dried Undaria powder and natural food. Survival rate, weight gain, soft body weight and shell length of abalone fed natural food were lowest (P<0.05) among all diet. Moisture, protein and lipid contents of soft body were not influenced by experimental diets except natural food. Lipid content of abalones fed natural food was significantly lower than those of abalone fed other diets (P<0.05). These data indicate that abalone can more efficiently utilize Sargassum than Ulva, Undaria, Laminaria or spirulina.

• ALGAE
• /
• v.32 no.4
• /
• pp.325-336
• /
• 2017

Intertidal community recovery and resilience were investigated with quantitative and qualitative perspectives as a function of disturbance timing. The study was conducted in a lower intertidal rock bed of the southern coast of South Korea. Six replicates of artificial disturbance of a $50cm{\times}50cm$ area were made by clearing all visible organisms on the rocky substrate in four seasons. Each of the seasonally cleared plots was monitored until the percent cover data reached the control plot level. There was a significant difference among disturbance timing during the recovery process in terms of speed and community components. After disturbances occurred, Ulva pertusa selectively preoccupied empty spaces quickly (in 2-4 months) and strongly (50-90%) in all plots except for the summer plots where non-Ulva species dominated throughout the recovery period. U. pertusa acted as a very important biological variable that determined the quantitative and qualitative recovery capability of a community. The qualitative recovery of communities was rapid in summer plots where U. pertusa did not recruit and the community recovery rate was the lowest in winter plots where U. pertusa was highly recruited with a long duration of distribution. In this study, U. pertusa was a pioneer species while being a dominant species and acted as a clearly negative element in the process of qualitative recovery after disturbance. However, the negative effect of U. pertusa did not occur in summer plots, indicating that disturbance timing should be considered as a parameter in understanding intertidal community resilience in temperate regions with four distinct seasons.

• ALGAE
• /
• v.31 no.1
• /
• pp.49-59
• /
• 2016

Ulva pertusa, a common bloom-forming green alga, was used as a model system to examine the effects of elevated carbon dioxide (CO₂) and temperature on growth and photosynthetic performance. To do this, U. pertusa was grown under four temperature and CO₂ conditions; ambient CO₂ (400 μatm) and temperature (16℃) (i.e., present), elevated temperature only (19℃) (ET; i.e., warming), elevated CO₂ only (1,000 μatm) (EC; i.e., acidification), and elevated temperature and CO₂ (ET and EC; i.e., greenhouse), and its steady state photosynthetic performance evaluated. Maximum gross photosynthetic rates (GP_max) were highest under EC conditions and lowest under ET conditions. Further, ET conditions resulted in decreased rate of dark respiration (R_d), but growth of U. pertusa was higher under ET conditions than under ambient temperature conditions. In order to evaluate external carbonic anhydrase (eCA) activity, photosynthesis was measured at 70 μmol photons m⁻² s⁻¹ in the presence or absence of the eCA inhibitor acetazolamide (AZ), which inhibited photosynthetic rates in all treatments, indicating eCA activity. However, while AZ reduced U. pertusa photosynthesis in all treatments, this reduction was lower under ambient CO₂ conditions (both present and warming) compared to EC conditions (both acidification and greenhouse). Moreover, Chlorophyll a and glucose contents in U. pertusa tissues declined under ET conditions (both warming and greenhouse) in conjunction with reduced GP_max and R_d. Overall, our results indicate that the interaction of EC and ET would offset each other’s impacts on photosynthesis and biochemical composition as related to carbon balance of U. pertusa.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.15 no.2
• /
• pp.99-104
• /
• 2009

The species composition and seasonal patterns in marine benthic algal community at intertidal zone in Jinhae Bay were investigated seasonally throughout 2007. A total of 45 species, 6 Chlorophyta, 10 Phaeophyta, and 29 Rhodophyta, were recorded, and dominant species were Ulva pertusa, U. conglobata, Sargassum horneri, Gelidium divaricatum, Gracilaria textorii, and Polysiphonia morrowii during study periods. The number of species were differed with seasons and stations; Higher number of algal species was 42 species in winter, whereas 33 species was lower in summer. The number of algal species were higher at station 1,7,8, while the lower value was at station 2, 3 than other stations. The differences of marine benthic algal composition at each station in MDS ordination due to the physical characteristics and local topography.