• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.101-105
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• 2020

Ralfsia longicellularis is known as an endemic species in Far East Asia. In this study, we report R. longicellularis as a new record from Korea based on morphological and molecular analyses. Molecular analyses based on plastid-encoded rbcL gene sequences and morpho-anatomical studies were undertaken on Ralfsia species, a poorly studied genus from Korea. Ralfsia longicellularis is mainly characterized by a dark brown thallus; 770-1200 ㎛ thick, curved cells in the creeping and ascending parts of the filaments; basal layer and erect filament cells with a width-to-length ratio of 1 : 1.5 to 10; narrowshaped sporangia on-stalk cells at the base of the paraphyses; and mostly uniseriate plurilocular reproductive organs capped with 1-2 sterile cells. The R. longicellularis samples from Korea in this study were similar to ones collected from the type locality (Peter the Great Bay, Russia) in morphology. The rbcL analyses also revealed that our Korean R. longicellularis samples were placed in the same clade with Russian materials, within a Ralfsia clade but distinct from the congeners.

• Journal of Integrative Natural Science
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• v.4 no.1
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• pp.72-78
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• 2011

Morphological and anatomical characters of Amphiroa misakiensis Yendo are investigated with field materials and taxonomic accounts are given to the species. The plants grow on rocks, mussels or non-articulated corallines from the subtidal zone of Cheju island, and is characterized by recumbent and spreading habit from the substrate. The species is well defined by about 4 cm height, loosely tufted thallus with irregularly dichotomous branches, flat and irregularly broad intergeniculum in upper part, geniculum developing by cracking and sloughing of calcified cortical tissue overlying uncalcified genicular tissue, five to thirteen-tiered geniculum with unequal length, and conceptacles buried in cortices of intergeniculum. Reproductive structures in tetrasporangial, male and female plants are typical of Amphiroa. The structure and developmental patterns of conceptacles are very similar to those shown in previous studies.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.4
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• pp.196-205
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• 2011

To investigate the contribution of macroalgae to biogeochemical nutrients and carbon cycles, we measured the uptake rates of nutrients and $CO_2$ and characteristics of fluorescence of Saccharina japonica (Laminaria japonica Areschoug) using an incubation method in an acrylic chamber. From January to May 2011, S.japonica was sampled at Ilkwang, one of well-known macroalgae culture sites around Korea and ranged 46~288 cm long and 4.8~22.0 cm wide of whole thallus. The production rate of dissolved oxygen by S. japonica (n=25) was about $6.9{\pm}5.8{\mu}mol\;g^{-1}$ fresh weight(FW) $h^{-1}$. The uptake rate of total dissolved inorganic carbon ($TCO_2$), calculated by total alkalinity and pH, was $8.9{\pm}7.9{\mu}mol\;g^{-1}\;FW\;h^{-1}$. Mean nutrients uptake were $175.6{\pm}161.1\;nmol\;N\;g^{-1}\;FW\;h^{-1}$ and $12.7{\pm}10.1\;nmol\;P\;g^{-1}\;FW\;h^{-1}$. There were logarithmic relationships between thallus length and uptake rates of nutrients and $CO_2$, which suggested that younger specimens (<100-150 cm) were much more efficient at nutrients and $CO_2$ uptake than old specimens > 150 cm. There was a positive linear correlation ($r^2$=9.4) existed between the dissolved oxygen production rate and the $TCO_2$ uptake rate, suggesting that these two factors may serve as good indicators of S. japonica photosynthesis. There was also positive linear relationship between maximal quantum yield ($F_v/F_m$) and production/uptake rates of dissolved oxygen, $TCO_2$ and phosphate, suggested that $F_v/F_m$ could be used as a good indicator of photosynthetic ability and $TCO_2$ consumption of macroalgae. Maximum relative electron transport rate ($rETR_{max}$) of S. japonica increased as thallus grew and was high in distal part of thallus which may be resulted from the increase of photosynthetic cell density per area. The annual $TCO_2$ uptake by S. japonica in Gijang area was estimated about $1.0\sim1.7{\times}10^3C$ ton, which was about 0.02-0.03% of carbon dioxide emission in Busan City. Thus, more research should be focused on macroalgae-based biogeochemical cycles to evaluate the roles and contributions of macroalgae to the global carbon cycle.

• ALGAE
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• v.24 no.4
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• pp.239-248
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• 2009

Fluorescence and electron microscopy were used to examine epidermal shedding in the fucoid alga, Ascophyllum nodosum. Mature meristoderm cells are ca. 50-100 x 30-40 ${\mu}m$ and highly polarized, with a single nucleus and chloroplasts near the base of the cell. Nuclei in these cells undergo mitosis when they are dividing to form a new cortical cell towards the middle of the frond, or anticlinal divisions as part of frond elongation. However, cytokinesis also occurs regularly in these cells when a new periclinal wall is deposited at about 30% of the cell length from the apical end. The newly formed distal cells are anucleate and without chloroplasts. Following cytokinesis the tangential walls then break at the thinnest point. The whole process is synchronous in adjoining epidermal cells across large areas of the frond surface, and this layer dehisces from the thallus. This is the only known plant or algal system in which cytokinesis regularly occurs in the absence of mitosis. We consider this process a novel form of programmed cell death.

• ALGAE
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• v.22 no.1
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• pp.17-21
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• 2007

Sargassum filicinum Harvey, a brown alga (Phaeophyceae) native to Northeastern Asia, has been recently reported from the coast of Southern California (USA). Here we report the occurrence and range extension of this introduced species, as we found the alga at La Jolla and Rancho Packard in Todos Santos Bay, Baja California, Mexico. The first collections of S. filicinum correspond to several immature plants, found on September 8, 2005, drifting in the intertidal zone at La Jolla. Later on November 9, 2006, we found a well-established population in Rancho Packard in the middle intertidal zone to 2 m depth. Since S. filicinum is an annual monoecious species with air bladders, the risk there is a high risk of spreading rapidly along the Pacific, as in the case for S. muticum. The population in Rancho Packard extends 500 m along the coast, consisting mainly of young plants with an average length of 30 cm and a density of 5 thallus/m2. This is the first record of this invasive species for the Mexican Pacific coast, and it represents the southern limit along the Pacific coast of North America. This finding suggests that this invasive species has successfully colonized the Pacific coast of North America and its distributional range is still expanding.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.379-388
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• 1983

The subtidal benthic algal communities of Dolsan-island in the southern coast of Korea were surveyed by means of SCUBA diving. The vertical zonation is recognized into three groups; upper, middle and lower subtidal zones. The representative species in each group throughout the year are Ulva pertusa, Codium fragile, Chondria crassicaulis and Gigartina tenera in the upper, Myagropsis myagroides and Sargassum tortile in the middle, and Plocamium telfairiae, Callophyllis japonica and Symphyocladia linearis in the lower zone. According to the normal association analysis by $2{\times}2$ contingency table and chi-square calculation among 29 quadrats, the algal communities are divided into 9 groups which are dominated by Sargassum tortile, Myagropsis myagroides, Chondria crassicaulis, Codium fragile, Pterocladia tenuis, Gigartina tenera, Gracilaria textorii. The thallus length and standing crops of Myagropsis myagroides show the highest value in spring and the lowest in summer.

• ALGAE
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• v.27 no.1
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• pp.33-42
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• 2012

Population ecology of Palmaria palmata is described from the intertidal zone of Digby Neck and adjacent islands of Nova Scotia. The primary objectives were: to evaluate the difference in habitat specialization and population structure of P. palmata between harvest and non-harvest shores, and to characterize differences in thallus structure and frond sizes between epilithic and epiphytic populations. Harvest shores were gently sloping boulder fields with boulders typically about 0.5-1.0 m with dense cover of P. palmata on many of the rocks. Non-harvest shores (with or without P. palmata) consisted of boulders that were smaller or larger than harvest shores, or bedrock; when P. palmata was present on nonharvest sites it was typically epiphytic on other algae (e.g., Fucus spp., Mastocarpus stellatus, Devaleraea ramentacea). Harvestable epiphytic populations occurred only in high current areas. While there was little difference in average cover of P. palmata harvest and non-harvest shores ($31.2{\pm}13.7%$ vs. $19.4{\pm}7.3%$, mean ${\pm}$ standard deviation [SD]), the cover of P. palmata on harvest shores was highly skewed such that individual boulders often had >90% cover while adjacent rocks had little. Frond length of large fronds was greater on harvested shores, and mean frond density ($g\;m^{-2}$) was three times higher than the mean density on the non-harvested shores. Frond lengths of entire epiphytic and epilithic frond complements of 119 thalli from harvest beaches showed no difference in mean size of the largest fronds, and no difference in frond number per holdfast when epiphytic and epilithic thalli were compared.

• Journal of Life Science
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• v.16 no.5
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• pp.723-728
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• 2006

The species of Grateloupia filicina, Grateloupia divaricata in East Sea were investigated taxonmically in order to clarify taxonomic position. The ecological character, external morphology, anatomy of vegetative structure. Blade length are $15{\sim}40\;cm$, erect from discoidal holdfast of $3{\sim}10\;mm$ in diameter. Stipe $1{\sim}2.5\;cm$ long, narrowly cylindrical below, compressed above Grateloupia filicina. Main axis are long and compressed, $3{\sim}7\;mm$ broad in broadest part. Colors are scarlet to light red. Blade length are $10{\sim}25\;cm$, erect from discoidal holdfast of $3{\sim}8\;cm$ in diameter Grateloupia divaricata. Stipe are single and simple $2{\sim}5\;mm$ broad. Thallus composed of cortex and medulla in section ; cortex composed of $9{\sim}10$ layers of anticlinally arranged cortical cell, divided into outer, middle and inner parts. Partial fragments of nuclear 18S rDNAs from the two species of Grateloupia (Rhodophyta) were amplified using the PCR reaction and sequenced to compare their similarity. The partial sequences showed 98.9% similarity each other. Grateloupia filicina has 371 bp sizes and Grateloupia divaricata has 372 bp size. The G+C contents of Grateloupia filicina is 54.3% and Grateloupia divaricata is 53.64%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.57-64
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• 2004

Effects of light and temperature on the nitrate uptake and germling growth of Enteromorpha compressa (L.) Greville (Chlorophyta) were studied based on samples from Cheongsapo near Busan, Korea. In addition, their effects on fatty acids composition in thallus were examined. Nitrate uptake showed saturation kinetics. $V_{max}$ (maximal uptake rate) and its $K_s$ (half-saturation constant) at $20^{\circ}C,\;80\;{\mu}mol\;m^{-2}s^{-1},$ white light were $1.571\;{\mu}mol{\cdot}g\;fr\;wt^{-1}{\cdot}h^{-1}$ and 3.56 ${\mu}M$, respectively. In nitrate uptake with irradiance, wavelength and temperature, its rate represented respectively the highest value as $1.405\pm0.020,\;0.623\pm0.040,\;1.422\pm0.022\;{\mu}mol{\cdot}g\;fr\;wt^{-1}{\cdot}h^{-1}\;at\;100\;{\mu}mol\;m^{-2}s^{-1},$ red light, $20^{\circ}C$ and exhibited significant difference among the examined conditions (p<0.001). Germling growth of E. compressa also showed saturation kinetics, and $V_{max}$ and its $K_s$ value at $20^{\circ}C,\;100\;{\mu}mol\;m^{-2}s^{-1},$ 12:12 h were $56.18\%\;day^{-1}$ and 0.33 ${\mu}M$, respectively. SGR (specific growth rate) recorded a maximal value as 49.33-54.80, 39.07-50.72, $47.20-54.53\%\;dat^{-1}$ at $120\;{\mu}mol\;m^{-2}s^{-1},$ blue light and $18^{\circ}C$ respectively, and showed significant difference (p<0.001). Red light made the effective nitrate uptake, but germling growth was largely limited by the light. In fatty acids analysis, PUFAs (polyunsaturated fatty acids) were high at blue light, $18^{\circ}C,\;100\;{\mu}M\;NO_3^-.$ However, irradiance did not affect the production of PUFAs. In conclusion, nitrate uptake and germling growth of E. compressa showed saturation kinetics to external nitrate concentration, and were significantly affected by irradiance, wave length and temperature. Fatty acid composition was also influenced by the factors except for irradiance. Their maximal values, together with the highest production of PUFAs, were found at blue light band, $20^{\circ}C,\;100\;{\mu}mol\;m^{-2}s^{-1},\;and\;100\;{\mu}M\;NO_3^-.$