• ALGAE
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• 제23권1호
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• pp.53-61
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• 2008

In order to understand variation and relationship between standing crops and biomass of phytoplankton dominant species for the long term periods, this study was seasonally investigated in the marine ranching ground of Tongyeong coastal waters from 2000 to 2007. Total 268 taxa representing 217 Bacillariophyceae, 46 Dinophyceae, 4 Dictychophyceae, 1 Euglenophyceae were observed in phytoplankton communities. Dominant species consisted of 5 species as standard in standing crops: Chaetoceros curvisetus (18.01%), Chaetoceros socialis (12.95%), Skeletonema costatum (8.39%), Chaetoceros compressus (6.87%), Asterionellopsis glacialis (5.02%). However, to determine dominant species as biomass concept, Ditylum brightwellii, Guinardia striata, Rhizosolenia spp. and Skeletonema costatum were occupied with dominant species (19.67%). As determining for cell sizes, dominant species were divided with two groups such as micro- and nanophytoplankton (standing crops) and mesophytoplankton (biomass). However, Skeletonema costatum in anophytoplankton was associated to affect fluctuation between standing crops and biomass.

• 한국수산과학회지
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• 제23권6호
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• pp.468-474
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• 1990

휴안포자를 형성하는 과편모조류중 우리나라 남해동부와 동해남부의 연안수역 특히 진해만에서 1982년 이래 3월부터 9월에 걸쳐 적조를 일으킨 종은 8종이었으며 이들은 6종의 과편모조류와 2종의 녹색편모조류로 구성되었다. 계절별로는 이른 봄철에 Scrippsiella trochoidea와 Heterocapsa triquetra종이, 늦봄에 Heterosigma akashiwo가 그리고 여름철에는 Gyrodinium instriatum과 Pheopolykrikos hartmannii가 적조를 일으켰다. 한편 Cochlodinium sp.와 Alexandrium affine는 늦여름부터 가을철에 적조를 일으켰다. 이중 Heterosigma akashiwo는 매년 같은 곳에서 같은 시기에 발생하는 경향을 뚜렷히 나타냈으며 Cochlodinium sp.에서도 이와 같은 특성을 발견할 수 있었다. 한편 적조발생시의 밀도는 $10^3\~10^5\;cells/ml$ 수준이었으며, 밀도변화는 환경특성 보다는 오히려 세포의 크기에 따라 변화하고 있었다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2000년도 정기총회 및 봄 학술발표회
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• pp.251-254
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• 2000

In this study, we investigated vertical distribution and seasonal changes of phytophlankton community in the Hae-Dong Reservoir from March 1999 to Feburary 2000. This reservoir is relativly small (surface area, 2.7 $km^2$) and is the source of drinking water supply to the eastern part of Pusan City. Samples were collected at 2 sites (1, 3, and 6 m; site 1, in front of the dam; site 2, inlet). The dominant group was Bacillriophyceae at both sites (over 63%), and other groups exhibited seasonal changes (high cyanobacterial density in summer; green algal communities in winter). Chrysophyceae and Dinophyceae were maintained lower level during the study period. Along the water depth, all classess of phytoplankton did not show distintive vertical distribution at both sites except during the blue-green algal bloom in the middle of July and late September. The phytoplankton community dynamics in the Hoe-Dong Reservoir was strongly affected by the hydrological factors such as concentrated precipitation and short retention time.

• 환경생물
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• 제36권1호
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• pp.82-89
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• 2018

남해 중앙부의 가막만 입구해역에 설치된 sediment trap의 와편모조 시스트 및 시스트에서 발아된 유영세포에서 국내 미기록 와편모조 시스트 9종을 관찰하였기에 형태적 특징을 고찰하였다. 미기록 와편모조 시스트는 모두 종속영양종으로 와편모조문 (Dinophyta), 와편모조강 (Dinophyceae), 페리디니움목 (Peridiniales)에 속하였다. 미기록 종은 Brigantedinium majusculum (Protoperidinium sinuosum), cyst of Diplopsalis lebourae, cyst of Protoperidinium excentricum, cyst of Pt. sp. cf. nudum, cyst of Pt. obtusum, cyst of Pt. ventricum, cyst of Protoperidinium sp.1, cyst of Protoperidinium sp.2 및 미동정된 cyst of Peridinales 등이었다.

• 환경생물
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• 제37권3호
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• pp.268-277
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• 2019

Severe damages will result in human society, when several different critical natural phenomena coincide. One example relates to the resting cysts of Alexandrium species (dinoflagellates that cause paralytic shellfish poisoning), which are preserved in surface sediments throughout Osaka Bay, Japan. These cysts have been found to accumulate particularly densely in shallow areas in the inner parts of Osaka Bay, where a tsunami caused by an earthquake could occur any time. Damage by a tsunami could cause a change of the coastal ecosystems at Osaka Bay including the resuspension of surface sediments containing resting Alexandrium tamarense cysts and the subsequent redistribution of the cysts in newly deposited sediment. Under certain environmental conditions, these cysts could germinate and form dense blooms, leading to paralytic shellfish poisoning. Such a scenario could also affect other coastal areas, including the southern coast of the Korean Peninsula.

• ALGAE
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• 제23권2호
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• pp.115-118
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• 2008

Cells of the dinoflagellate Peridinium were frequently observed in water samples of Togyo reservoir, and some species were responsible for dense blooms. Recently, we could identify them as P. bipes f. occultatum Lindem. and P. aciculiferum Lemm., considering morphology (Ki et al. 2005a; Ki and Han 2005b): However, some unidentified Peridinium cells with different shapes and body sizes were found among the samples collected during early spring. Here we describe their morphological characteristics such as thecal plate and body size to characterize its taxonomic identity by morphological characters. The formula of epithecal plates was recorded as 4 apical, 2 intercalary and 7 precingular plates (i.e. 4’', 2a, 7’'’') and the epicone in an apical view was symmetric. An apical pore was easy to make out under a light microscope. No cingular displacement was observed. The average body size was 33 $\mu$m in length with a range of 26-36 $\mu$m, and average 26 $\mu$m in width with a range of 21-31 $\mu$m, respectively; the cell was, therefore, shown slightly elongated. This way we identified Peridinium umbonatum Stein, 1883 for the first time from Korean freshwaters.

• ALGAE
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• 제30권1호
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• pp.49-58
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• 2015

In September 2007, reports of respiratory irritation and fish kills were received by the Florida Fish and Wildlife Conservation Commission (FWC) from the Jacksonville, Florida area. Water samples collected in this area indicated a bloom of Karenia brevis, the dinoflagellate that produces brevetoxin, which can cause neurotoxic shellfish poisoning. For the next four months, K. brevis was found along approximately 400 km of coastal and Intracoastal waterways from Jacksonville to Jupiter Inlet. This event represents the longest and most extensive red tide the east coast of Florida has experienced and the first time Karenia species other than K. brevis have been reported in this area. This extensive red tide influenced commercial and recreational shellfish harvesting activities along Florida's east coast. Fourteen shellfish harvesting areas (SHAs) were monitored weekly during this event and 10 SHAs were closed for an average of 53 days due to this red tide. The length of SHA closure was dependent on the shellfish species present. Interagency cooperation in monitoring this K. brevis bloom was successful in mitigating any human health impacts. Kernel density estimation was used to create geographic extent maps to help extrapolate discreet sample data points into $5km^2$ radius values for better visualization of the bloom.

• ALGAE
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• 제22권2호
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• pp.57-67
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• 2007

We analyzed the nuclear-encoded large subunit ribosomal RNA gene (LSU rDNA) sequences of 19 dinoflagellates occurring in costal waters off Korea and reconstructed a phylogenetic tree containing 74 representative species from 37 distinct genera. Of these, the LSU rDNA sequences of Amylax triacantha (Jörgensen) Sournia, Gonyaulax verior Sournia (= Amylax diacantha Meunier), Gyrodinium fissum (Levander) Kofoid et Swezy, Katodinium glaucum (Lebour) Lebour III, Noctiluca scintillans (Macartney) Kofoid et Swezy, Oxyphysis oxytoxoides Kofoid, and Pyrophacus steinii (Schiller) Wall et Dale are reported for the first time. Our LSU rDNA tree consistently placed Oxyrrhis marina Dujardin and N. scintillans at the most primitive positions, giving rise to a strongly supported monophyletic group of typical dinoflagellate species belonging to the Dinophyceae. The phylogenetic relationships among the typical dinoflagellates, however, were not resolved in the higher taxonomic levels in general. Only genera at terminal branches were usually supported with high confidence. The Dinophysiales, represented by Dinophysis species and O. oxytoxoides, formed a strongly supported monophyletic assemblage. The Gymnodiniales and Peridiniales were recovered as polyphyletic groupings. Members of the Gonyaulacales were consistently grouped together, but lacked statistical support. Within this order, the Ceratiaceae and Goniodomataceae each formed a monophyletic group, but the Gonyaulacaceae was polyphyletic. The phylogenetic relationships of the Gonyaulacaceae were generally congruent with differences in the combinations of the apical pore complex, hypothecal organization and thecal formula.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2005년도 봄 학술발표회지 제14권(제1호)
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• pp.241-244
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• 2005

The aim of this study was to determine the first outbreaks of nontoxic Gonyaulax polygramma Stein in Yeosu waters in place of harmful Cochlodinium polykrikoides Margalef, which has occurred annually in the same coastal region since 1995. The observation of cellular arrangement and structure by electron microscopy showed that G. polygramma isolated from Yeosu waters had a few spines connecting with mem-branes and prominent longitudinal ridges on the cell surface, with a cingular dis-placement 1.5 times their cell width. Furthermore, the location of the nucleus wasposterior of large oval formation according to electron microscopy. On 6 August, 2004,the first bloom of G. pozygramma occurred, the date of own its disappearance was with a maximum cell density of 8,000 cells ml$^{-1}$ on 21 August, 2004. During the period of this study, the horizontal distribution of sea water temperature and salinity showed a strong coastal front, whereas the front of DIN (Dissolved Inoganic Nitrogen) was significantly different between the occurrence and disappearance of G. polygramma blooms. These results suggested that the process of the breakdown of stratification by wind and a low level of inorganic nitrogen play important roles in the rapid growth of G. polygrmma, which is associated with a greater robustness in growth against DIN than that of C.polykrikoides in nature.

• ALGAE
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• 제21권4호
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• pp.433-443
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• 2006

This study was performed to understand the morphological and ecological characteristics of Peridinium bipes var. occultatum Lindem., which is the organism responsible for freshwater red tides in Sangsa dam and Miryang dam reservoirs. The samples were collected from April to July 2004 when the freshwater red tides occurred. In the study, we were able to differentiate P. bipes var. occultatum from P. bipes, a closely related species, by its smaller antapical horn size. In Miryang dam reservoir the red tide occurred only within the area of the upstream, but it was well developed in all of the water area in Sangsa dam reservoir. In 2004 average LTSI (Lake Trophic Status Index; Yang and Dickman, 1993) of Miryang dam reservoir was 3.53 of mesotrophic state and Sangsa dam reservoir was 8.59 of eutrophic state. It was determined, through culture experiments under various conditions that vitamins, trace elements, phosphorus and nitrogen were important contributing factors to the growth of P. bipes var. occultatum. A rapid toxic effect of P. bipes var. occultatum on aquatic organisms such of Daphnia magna and Oryzias latipes was not identified in this study.