• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.45 no.6
• /
• pp.694-703
• /
• 2012

To understand the characteristics of sedimentary and benthic environments in habitats of naturally-occurring intertidal benthic macroalgae, various geochemical parameters of sediment (grain size, ignition loss [IL], chemical oxygen demand [COD], and acid volatile sulfur [AVS]) and pore water (temperature, salinity, pH, and nutrients) were measured in the southern intertidal zone of Hampyeong Bay at two month intervals from April to October 2009. Ecological characteristics including the distribution and biomass of benthic macroalgae were also investigated. Benthic macroalgae were distributed below 4 to 5 m depth from mean sea level near the lower portion of the intertidal zone where air exposure time is relatively short. The distribution area and biomass of benthic macroalgae gradually decreased during the study period. The surface sediments in the benthic algal region were mainly composed of finer sediments, such as slightly gravelly mud and mud. The temperature, salinity, pH, and nutrient concentrations (except dissolved inorganic nitrogen) in pore water did not differ in regions with and without benthic macroalgae, whereas the mean grain size and the concentrations of IL, COD, and AVS in sediments were much higher in regions harboring benthic macroalgae. The correlation between mean grain size and IL in sediments displayed two distinct gradients and the slope was much steeper in regions harboring benthic macroalgae, indicating that the content of organic matter in benthic algal region is not solely dependent on mean grain size. Our results indicate that the benthic macroalgae in the southern intertidal zone of Hampyeong Bay play an important role in the accumulation of organic matter in sediment.

• Journal of Fisheries and Marine Sciences Education
• /
• v.29 no.2
• /
• pp.612-625
• /
• 2017

To grasp the algal vegetation using the occurred species number, biomass and dominant species, this study was performed in the subtidal zone of Muan-gun, in the intertidal zone of Jindo-gun and in the intertidal zone and subtidal zone of Geomundo, the south-eastern coast of Jeollanamdo, Korea in the spring 2014. The total occurred species was 140 ones including 10 chlorophytes(7.14%), 54 phaeophytes(38.57%) and 76 rhodophytes(54.29%); the biomass was $70,484g{\cdot}w{\cdot}w/m^2$ in total. The flora charateristic using R/P ratio, geographical distribution pattern of algae, at the Station 9-1(intertidal zone) in Geomundo was tropical; the flora at the Station 6 (Maengseong-ri, Sanjodo, Jindo-gun) and the Station 9-2(subtidal zone) in Geomundo were mixed; the others were arctic to temperate. The physiognomic types were also shown. Each species was classified into six functional-form groups, and two ecological state groups(ESG) were evaluated based on these groups. The coarsely branched-group of functional-form groups was 44% of total occurred species. The ESG II in all study sites was high, and this is maybe due to the environmental stress such as pollution and disturbance, etc.

• The Journal of the Convergence on Culture Technology
• /
• v.5 no.4
• /
• pp.467-472
• /
• 2019

Seaweeds are rich in in minerals, vitamins, proteins, and fiber, and are classified as green algae, and they are distributed on the coasts of Korea, East Asia, Oceania, etc. and are used as a health function material as well as food ingredients in our countries and countries. In this study, Codium fragile was extracted from ethanol and concentrated to confirm DPPH radical scavenging activity, SOD activity, FRAP and ABTS cation radical scavenging ability. As a result, DPPH scavenging activity was 0.83, 22.83, 38.27, 40.93, 45.60% at 6.25, 12.50, 25, 50 and $100{\mu}g/mL$, SOD-like activity were 23.13, 33.63, 33.93, 44.07 and 59.07%. FRAP and ABTS showed antioxidant activity in a concentration-dependent manner, as in the previous experiment. Therefore, this study confirmed that it can be used as a cosmetic material using Codium fragile, a natural material.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.52 no.5
• /
• pp.534-538
• /
• 2019

The distribution and characteristics of spawning beds of the Pacific herring Clupea pallasii, were observed by scuba diving in Jinhae Bay, Korea, with a focus on marine vegetation as adhesive substrates and egg density during the spawning season. In 2017, the fertilized eggs of C. pallasii were mainly found attached to the leaves of algae species Carpopeltis cornea, Gracilaria textorii, and Acrosrium polyneurum at the rocky shore in Wonpo-dong and Jeodo. The mean density of fertilized eggs in C. pallasii spawning beds was $153,776eggs/m^2$ off Wonpo-dong and $856,430eggs/m^2$ off Jeodo, giving an estimated total of $5.345{\times}10^9$ eggs in Wonpo-dong and $3.3074{\times}10^{10}$ eggs in Jeodo. We examined spawning beds with an area of $38,619m^2$ off Wonpo-dong and $34,760m^2$ off Jeodo. The choice of spawning bed may be affected by the composition of marine vegetation, such as the algal diversity of rocky shore environments, which could affect adhesive substrates and egg density during the spawning season. The results of the present study suggest that the spawning season of C. pallasii in Jinhae Bay is in January to mid-February.

• Journal of Species Research
• /
• v.11 no.3
• /
• pp.133-142
• /
• 2022

In 2020, 24 bacterial strains were isolated from algae, kudzu leaf, mud, pine cone, seashore sand, sea water, soil, tidal flat, and wetland from the Republic of Korea. Isolated bacterial strains were identified based on 16S rRNA gene sequences, and those exhibiting at least 98.7% sequence similarity with known bacterial species, but not reported in Korea, were highlighted as unrecorded species. These isolates were allocated to the phyla Bacteroidetes and Proteobacteria as unrecorded species in Korea. The four Bacteroidetes strains were classified into the families Chitinophagaceae, Flavobacteriaceae, and Sphingobacteriaceae (of the orders Chitinophagales, Flavobacteriales, and Sphingobacteriales, respectively). The 20 Proteobacteria strains belonged to the Aeromonadaceae, Marinobacter, Microbulbiferaceae, Enterobacteriaceae, Erwiniaceae, Morganellaceae, Yersiniaceae, Lysobacteraceae, Halomonadaceae, Moraxellaceae, Pseudomonadaceae, Steroidobacteraceae, Xanthomonadaceae, and Myxococcaceae (of the orders Aeromonadales, Alteromonadales, Cellvibrionales, Enterobacterales, Lysobacterales, Oceanospirillales, Pseudomonadales, Steroidobacter, Xanthomonadales, and Myxococcales). This study focused on the description of 24 unreported bacterial species in Korea in the phyla Bacteroidetes and Proteobacteria belonging to six classes.

• Ocean and Polar Research
• /
• v.33 no.spc3
• /
• pp.349-358
• /
• 2011

In order to ascertain latitudinal variation of lipid contents and compositions in copepods, we collected warm water copepod species (Euchaeta sp. and Pleuromamma spp.) from four different regions from low (sub-tropical) to mid (temperate) latitudes in the Northwest Pacific Ocean. Total lipid contents of Pleuromamma spp. were about 11 $ug{\cdot}ind^{-1}$ with little latitudinal variation, whereas Euchaeta sp. showed slightly higher lipid content (20 $ug{\cdot}ind^{-1}$) than Pleuromamma spp. with latitudinal gradient (low at subtropic and high at temperate). Wax esters, known as the major storage lipid classes, were found to be the dominant lipid classes (accounting for more than 35% of total lipids) in Euchaeta sp., whereas in Pleuromamma spp., phospholipids, known as cellular membrane components, were the dominant lipid classes. However, the exception was specimens from warm pool region exhibiting dominance in storage of lipids as a form of triacylglycerols. Among fatty acids, polyunsaturated fatty acids (PUFA), especially docosahexaenoic acid (DHA : 22:6(n-3)) (about 35% of total fatty acids), were most abundant in Euchaeta sp., while saturated fatty acids (SAFA), specially hexadecanoic acid (16:0) (about 30% of total fatty acids), were most abundant in Pleuromamma spp.. Among the neutral fraction of lipids, phytol, originated from the side chain of chlorophyll, was found in all samples which generally indicate active copepods feeding on algae. While only trace amounts of short-chain fatty alcohols were found in Pleuromamma spp., significant amounts of fatty alcohols were found in Euchaeta sp.. Particularly, significant amounts of long chain monounsaturated fatty alcohols (20:1 and 22:1), generally found in cold water species, were found in Euchaeta sp. from low latitudes. The latitudinal variation of trophic lipid markers in these copepods could be significantly related with in-situ food availability and species-specific diet preference. The result of this study suggests that the lipid contents and compositions in copepods may not only indicate their nutritional condition and feeding ecology but also provide insight into species-specific living strategies under different environmental conditions (i.e. water temperature, food availability).

• Journal of Aquaculture
• /
• v.11 no.2
• /
• pp.133-140
• /
• 1998

A 20-week growth trial was conducted in flow-through aquarum system to investigate the practical dietary carbohydrate sources for juvenile abalone (Haliotis discus hannai). Four replicate grops of the abalone averaging 0.125g were fed one of eight diets containing 24.2% wheat flour (WF), 20% dextrin (DEX), 20% sucorse (SUC), 10% $^{\alpha}$-potato starch+10% $^{\beta}$-potato starch (ab-S), 15% $^{\alpha}$-potato starch (a-S15), 20% $^{\alpha}$-potato starch (a-S20), 25% $^{\alpha}$-potato starch (a-S25), or mixture (MIX) with practical ingredients such as soybean meal, corn gluten meal, cotton seed meal and heat flour. In addition, these formulated diets were compare with macroalgae such as dried sea mustard Undaria (D-SM) or dried sea tangle Laminaria(D-ST). Survival rate, weight gain, shell growth and soft body weight of abalone were not significantly affected by the different dietary carbohydrate sources (P>0.05), whereas those fed a-S15 diet were slightly low. These values of abalone fed D-ST were lowest (P<0.05), followed by those fed D-SM. Lipid contents of soft body from abalones fed a-S25, D-ST or D-SM were significantly lower than those of abalone fed other diets (P<0.05). These data indicate that abalone can equally utilize any carbohydrate sources used in this study.

• Journal of Marine Life Science
• /
• v.5 no.2
• /
• pp.99-106
• /
• 2020

To investigate effect of variation in physiochemical conditions due to river discharge on phytoplankton, field surveys were conducted in the Seomjin and Yeongsan River estuaries from April to November 2016. The concentrations of DIN and DSi in Seomjin River estuary were gradually low as distance from upstream. On the other hands, the concentrations of DIN and DSi in Yeongsan River estuary were critically high at upstream, due to which is characterized as semi-enclosed eutrophic area. A total of 12 phytoplankton pigments were analyzed, and the distribution of each taxa was investigated using indicator for each phytoplankton taxa. Fucoxanthin, an indicator pigment of diatoms, showed an average of 0.61±1.00 ㎍ l^-1 and 0.76±1.22 ㎍ l^-1 in the Seomjin and Yeongsan River estuaries, respectively. Concentration of fucoxanthin was more than twice that of other pigments except chlorophyll a., indicating that diatoms were dominant taxa. Peridinin, an indicator pigment of dinoflagellate, showed some similar tendency to the microscopic observation, but mismatch results were also present, indicating a technical limitation of pigment analysis. Chlorophyll b, alloxanthin, and zeaxanthin, which are indicator pigments of green algae, cryptomonads, and cyanobacteria, were detected in both estuaries even though those taxa were not detected in microscopic observation. This indicates that the two estuaries were affected by freshwater species. Here, we can suggest that phytoplankton composition in estuary was directly influenced by the inflow from upstream. In particular, the phytoplankton population dynamics in Yeongsan River estuary was greatly associated with a large-scale artificial dyke, especially in summer rainy season. On the other hands, the seasonal and horizontal distribution of phytoplankton in Seomjin River estuary has changed along the salinity gradients and inflow-related changes.

• Korean Journal of Environment and Ecology
• /
• v.36 no.6
• /
• pp.627-638
• /
• 2022

This study was conducted at a village fishing farm on 4 peaks on the main island of Jeju Island and 2 peaks on an inhabited island to compare the distribution characteristics of seaweeds along the coast of Jeju Island from May to December 2018. A total of 101 species of seaweeds were surveyed, including 13 species (12.9%) of green algae, 24 species (23.8%) of Phaeophyta, and 64 species (63.4%) of Rhodophyta. The largest number of seaweeds appeared in May and the fewest in October, showing typical features of a temperate sea area. The number of seaweed species that appeared was 66 and 65 species at the water depths of 5 m and 8 m, respectively, and the largest was 74 species at 12 m. The number of seaweeds that appeared by area was the largest at 66 species on Udo Island, an eastern island near Jeju Island, and the lowest at 27 species in Pyoseon-ri, an eastern part of Jeju Island. The important values of emerging species were high in the order of, Ecklonia cavaand Corallina crassissima at 21.1% and 20.3%, respectively, Corallina aberransat 9.2%, Amphora ephedraeaat 6.2%, and Sargassum macrocarpumat 4.4%. Among seaweeds, an average of 11.2 species of coralline algae appeared, and the mean importance value was 32.6% in the sear area. The lowest importance value was 14.7% on Udo Island, and the highest was 41.0% in Pyoseon-ri. The mean ecological evaluation index (EEI) of seaweed colonies ranged from 2.1 to 10. It was the lowest at the water depth of 12 m in Pyoseon-ri in May and June and was 7.3 or higher in other areas, indicating good condition. This study rated the standardized ecological grade I for the water depth of 12 m on Udo Island and grade II for the water depths of 5 m and 8 m in Sagye-ri and on Chujado Island. Grade III was the water depth of 5 m and 12 m in Pyoseon-ri and Guideok 2-ri and the water depth of 5 m and 8 m in Pyeongdae-ri, and grade IV was the water depth of 8 m in Guideok 2-ri.

• The Korean Journal of Malacology
• /
• v.32 no.3
• /
• pp.231-240
• /
• 2016

Techniques were developed for holding and conditioning of Pacific oysters, Crassostrea gigas, in a closed recirculating system. Experimental adults were used 500 oysters ( x two system, total 1,000 oysters) which were collected in $20^{th}$ March 2016 from long-line aquaculture farm at the south coast of Korea. During conditioning periods concentrated live microalgae as Isochrysis sp. $15{\times}10^7cells/mL$, Tetraselmis sp. $2{\times}10^7cells/mL$ and Pheaodactylum sp. $18{\times}10^7cells/mL$ were added 5 L every day, respectively which micro algae were functioned as diets and biological filter. Over all experimental periods total water exchange rate was 21.3% (daily 0.5%). Over 42 days conditioning, female and male oysters were maturated 90.9% and 94.4%, respectively. Survival rate was 98.7%. Mean shell hight (8.3 mm), total wet weight (19.2 g), meat wet weight (5.0 g) and shell wet weight (13.6 g) were significantly increased (P < 0.05). Water quality parameters including the water temperature ($22.1{\pm}0.4^{\circ}C$), salinity ($24.9{\pm}04$), dissolved oxygen (5.1-7.9 mg/L) and pH ($7.93{\pm}0.15$) were kept stable. Concentration of dissolved inorganic nutrient as ammonia (1.96-0.35 mg/L), nitrite (0.03-0.16 mg/L), nitrate (1.34-0.47 mg/L), DIP (0.42-0.03 mg/L) and silicate (3.83-0.00 mg/L) were significantly decreased throughout experiment except nitrite which was increased (P < 0.05), but nitrogenous components stayed below toxic levels (ammonia 0.0-5.5 mg/L, nitrite 0.0-460.0 mg/L) which indicated that closed recirculation system with microalgae based bio-filter could supply sufficiently environment condition to holding and conditioning of oyster.