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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
The Korean Society of Phycology
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Volume & Issues
Volume 11, Issue 4 - Dec 1996
Volume 11, Issue 3 - Sep 1996
Volume 11, Issue 2 - Jun 1996
Volume 11, Issue 1 - Mar 1996
Selecting the target year
Reproduction in Scenedesmus
Trainor, Francis R. ;
ALGAE, volume 11, issue 2, 1996, Pages 183~183
Scenedesmus species are widely distributed in fresh waters throughout the world. Two basic types would include those with fusiform or spindle shaped cells along with those possessing oblong-ovate cells; the latter are often spiny. Inasmuch as the basic form is a simple colony, often consisting of but four cells, one is tempted to believe that we can easily understand Scenedesmus reproduction, as well as to identify specimens encountered. Colonies reproduce asexually by successive divisions of the protoplast within the parent cell wall, and when progeny are released, the parent wall remains. Young spiny colonies have all of their ornamentation upon their release. Daughter colony may be morphologically identical to the parent, or they may exhibit remarkable phenotypic plasticity The plasticity is best kwon within spine-bearing species. Inasmuch as environmental conditions determine what cytological features no displayed, the individual coenobial types for each genotype are termed ecomorphs. Since this plasticity would include production of spiny unicells, there are obvious taxonomic complications. In carefully controlled laboratory experimentation, an ordered sequence of ecomorph development has been detected, with spines produced at predetermined sites. The most spiny morphs, whether unicells or colonies, develop when conditions are optimal. These ecomorphs, which easily remain in the plankton, are recorded early in log growth. In nature one would expect to observe them in the spring. Spineless coenobia, lacking appendages which provide frictional resistance to settling, are detected late in the season or when growth conditions are not optimal. Scenedesmus sexual reproduction has been reported only in the laboratory, although flagellated cells (gametes) have been observed in outdoor fish ponds. Both spiny and spine-less species may reproduce sexually, but species such as S. obliquus (Turp.)
. provide the most favorable material. Gametes are without walls, biflagellated, photosynthetic and heterothallic, however, thus far they have not been produced in large numbers. Once active, gametes clump and pair; fusing gametes soon form a quadriflagellated zygote. The latter enlarges, produces a thick smooth wall and upon germination numerous (up to 32) single cells result. Presumably the mating types are represented by half that number.
Far-UV Action on Growth, Pigmentation and Photosynthesis of Ulva lactuca (Chlorophyta)
Han, Tae-Jun ;
ALGAE, volume 11, issue 2, 1996, Pages 203~203
Growth, pigmentation and photosynthesis were determined for Ulva lactuca L. exposed to far-UV irradiation and non-irradiation treatment. UV-irradiated discs cut from thalli showed a severe growth inhibition in surface area but not in fresh weight compared with control samples. On exposure to 4 min UV the level of chlorophylls fell sharply whereas no such decrease occurred in carotenoid contents. The chlorophyll a/b ratio remained rather constant. The reduction in chlorophylls paralleled with the decrease in photosynthetic activity. UV-photoinhibition was characterised by a significant depression in maximum light-saturated rates of photosynthesis without any change in quantum efficiency. Respiration was not affected by UV as much as photosynthetic oxygen production.
Phytoplankton Community of Alalay Pond, Cochabamba, Bolivia
L., Eduardo A. Morales ; Trainor, Francis R. ;
ALGAE, volume 11, issue 2, 1996, Pages 207~207
The extensive variety of Bolivian aquatic ecosystems has not yet been studied. The geographic richness of the country makes difficult the compilation of data by a limited number of native limnologists. Most of the isolated studies have been conducted by foreign researchers and do not reflect the variations of aquatic conditions even in the Departments of La Paz and Cochabamba, to which such studies are restricted. In the valley region Alalay Pond is one of the few bodies of water that has received attention. This special consideration was driven by the concern for protecting the health of the surrounding population from contaminated and eutrophicated waters. After analysis of the phytoplanktonic community as well as the physico-chemical conditions of the water, we may conclude that the pond was in a eutrophic stage during the period July 1989 to June 1990. The concentrations of nitrates, phosphates, and sulfates reveal such a condition. These factors, as well as temperature, alkalinity, and conductivity are inversely correlated to the hydrological fluctuations in the pond. Hydrogen ion concentrations are very high (pH around 10), but remain fairly constant through the year of study, due to a buffer effect provided by the carbonate-bicarbonate system. The phytoplankton assemblage is characteristic of eutrophic waters. Sixty four species belonging to four Divisions were identified: Cyanophyta (22 species), Chlorophyta (25 species), Euglenophyta (5 species), and Bacillariophyta (12 species). Three species of blue-green algae (cyanobacteria) were dominant, namely Anabaena spiroides, Spirulina laxa, and Oscillatoric obtusa. The number of individuals was influenced mainly by nitrates; differences in their horizontal distribution may be due the fact that the organisms responded differently to varying physico-chemical conditions in each zone. The Shannon species diversity index also confirms the fact that the pond is in a eutrophic stage. Incresases in water level led to high diversity, high richness, and high evenness; while lower diversity and low specific richness and evenness were characteristic during the dry season.
A Study on the Phytoplankton in the Paldang Dam Reservoir II. The Changes of Phytoplankton Species Composition
Chang, Yoon-Kyung ; Jeon, Sook-Lye ;
ALGAE, volume 11, issue 2, 1996, Pages 217~217
Changes of phytoplankoun species composition in the Paldang Dam Reservoir were investigated and compared with the data reported since the construction of the Paldang Dam in 1972. Collections were made at four stations in the Paldang Dam Reservoir from April 1994 to October 1995. Diatoms were not included in this report. A total of 112 taxa belonging to 6 phyla, 7 classes, 11 orders, 22 families, 54 genera, 107 species and 5 varieties were identified. The most abundant algal group was Chlorophyta with 88 taxa, followed by Cyanophyta with 9 taxa, 5 taxa of Chrysophyta exclusive of diatoms, 4 taxa each of Euglenophyta and Pyrrophyta and 2 taxa of Cryptophyta. Species of Chlorophyta such as Pandorina morum, Chlorella vulgaris, Sphaerocystis schroeteri, Scenedesmus maximus, Scenedesmus grahneisii, Coelastrum polychorum, Micractinium pusillum, Dictyosphaerium anomallum dominated during the spring and summer in 1994. Species of Cyanophyta; Anabaena spiroides, Merismopedia tenuissima, Aphanocapsa sp. were abundant from June to August. The total cell number was highest in August 1994 and dropped sharply in October which became lowest in December through February, then gradually increased from April to August. Aphanocapsa, Merismopedia, Oscillatoria, Coelastrum and Scendesmus contributed to the highest cell number in August 1994. The dominant algal group during 1980's was Bacillariophyceae but Chlorophyta and Cyanophyta increased rapidly and shifted the component of dominant species from Bacillariophyceae to Bacillariophyceae-Chlorophyta and Cyanophyta complex in 1990's. This indicates the gradual eutrophication of the Paldang Dam Reservoir.
Contribution of Primary Production of Phytoplankton to Organic Pollution in a Eutrophic River, the Naktong River
Kim, Bom-Chul ; Kim, Dong-Sup ; Hwang, Gil-Son ; Choi, Kwang-Soon ; Heo, Woo-Myung ; Park, Won-Kyu ;
ALGAE, volume 11, issue 2, 1996, Pages 231~231
To evaluate the contribution of phytoplankton to organic pollution in the Maktong River, biomass and production of phytoplankton and COD were measured at 10 sites of the main stream and 6 of tributaries from May to October in 1994. Chlorophyll a concentration and COD ranged
and 4-24 mg/l, respectively, at study sites of the main stream. Contribution of algal COD to total COD showed positive correlation with chlorophyll a concentration, and the ratios of algal COD to total COD varied 4-65% (average: 24%). Allochthonous organic carbon loading into the Naktong River was contributed by 36.5% from the main stream (Kangjong), 23.0% from the Nam River and 19.5%, of the Kumho River. Autochthonous organic carbon loading by production of phytoplankton ranged 24-69% (average: 49%) of the total loading. The results indicate that phosphorus, which is a key nutrient of the phytoplankton growth, as well as organic carbon loading must be controlled for improving the water quality of the Naktong River.
Bloom-forming Blue-green Alga, Microcystis flos-aquae, in the Lake around Reclaimed Area of Seosan
Kim, Gwang-Hoon ; Cho, Sam-Rae ; Mun, Hyeong-Tae ;
ALGAE, volume 11, issue 2, 1996, Pages 239~239
Effect of nutrient on growth characteristics of bloom-forming blue-green alga, Microcystis flos-aquae were investigated in the lake around reclaimed area of Seosan. Bloom of M. flos-aquae was observed during June 14 1994 through October 12 1994. The temperature ranged
during the time. Maximum cell concentration reached as high as
at August 10. The blooming area spread entire lake for two months. During the bloom, pH of the water stayed alkaline (pH 8.1-8.7), and
concentration was close to 0.05 mg/l. The thermophilic property of this species and high concentration of
in the water appear to be the main causes of bloom of the species in the lake.
Increase of in vivo Nitrate Reductase Activity in Ulva pertusa Kjellman during Early Exposure
Jun, Bang-Ook ; Chung, Ik-Kyo ;
ALGAE, volume 11, issue 2, 1996, Pages 243~243
In vivo nitrate reductase activity increased up to 3-fold when the thalli of Ulva pertusa were exposed at low tide. But in vitro activity, nitrate uptake rate and the nitrogen content did not significantly change. The results suggest that increase of in vivo nitrate reductase activity does not come from thallus dehydration. Rather it seems that increase of in vivo nitrate reductase activity is the process that occurs before thallus dehydration during exposure and may allow quick metabolism of restored nitrate in the resubmerged thallus of Ulva pertusa.