• 환경생물
• /
• 제36권3호
• /
• pp.260-270
• /
• 2018

A study describing unrecorded and taxonomically undescribed indigenous species is in progress since 2006. Samples were collected from many sites in coastal waters and offshore of Korea as well as from Jeju Island. Since 2008, we have found ten unrecorded species of four genera belonging to family Dinophysaceae, Gonyaulacaceae, Gymnodiniaceae, and Heterocapsaceae. The species are as follows, Dinophysis elongata (2016 winter), D. nasuta (2016 winter), Gonyaulax alaskensis (2016 winter), G. diegensis (2017), G. monospina (2008), Amphidinium flagellans(2017), Heterocapsa circularisquama (2017), H. horiguchii (2017), H. lanceolata (2017), and H. pygmaea (2017) (note; The numbers in the parenthesis refer to the year in which the species was reported as unrecorded indigenous species by National Institute of Biological Resources, NIBR hereafter). Among them, seven species were described as newly recorded species in Korean waters, and three have been re-described in this study.

• ALGAE
• /
• 제18권4호
• /
• pp.281-288
• /
• 2003

To study the environmental features causing a bloom of the novel dinoflagellate Heterocapsa circularisquama (Dinophyceae), hydrographic and chemical aspects were measured in the Uranouchi Bay, Kochi Prefecture, Japan, from January to December, 1997. The cell density of H. circularisquama increased rapidly in early October, and dropped sharply in mid-October. Growth rate of H, circularisquama during bloom period appeared 1.50 division day$^{-1}$ under high water temperature (25$^{\circ}C$) and salinity (32 psu) conditions. Althought the result from hydrographic aspect indicated good condition for their growth, dissolved inorganic phosphorus (DIP) concentration in surface layer before bloom formation was less than 0.70uM, which is lower than their half saturation constant(Ks). Dissolved inorganic nitrogen(DIN): DIP ratio was > 30, indicating potential P-limitation. However, before bloom formation period of H. circularisquama, DIP concentrations were high in bottom layer (> 4.0 uM). Some studies reported that H. circularisquama had the ability to migrate vertically and to utilize dissolved organic phosphorus (DOP). Thus, DIP in bottom layer might have been utilized by H. circularisquama for their growth.DOP might have weakly affected their growth because of low reactive DOP concentrations owing to low DOP concentration (ca. 0.39 uM). Thus, if nutrient condition of bottom layer in Uranuchi Bay is not improved, the outbreaks of H. circularisquama red tides may became an annual feature.

• The Plant Pathology Journal
• /
• 제28권4호
• /
• pp.433-438
• /
• 2012

Dinoflagellates are considered one of the most abundant and diverse groups of marine microplankton and viruses are recognized as one of the significant factors affecting the plankton dynamics. Here, we report basic characteristics of a new dinoflagellate-infecting virus, Heterocapsa pygmaea DNA virus (HpygDNAV) which infects a toxic dinoflagellate, H. pygmaea. HpygDNAV is a polyhedral large virus (ca. 160-170 nm in diameter) propagating in its host's cytoplasm. Because of the virion size, appearance in thin sections, and propagation characteristics, HpygDNAV is assumed to harbor a large double-stranded DNA genome; i.e., HpygDNAV is most likely a nucleocytoplasmic large DNA virus (NCLDV) belonging to the family Phycodnaviridae. Its infectivity is strain-specific, rather than species-specific, as is the case for other algal viruses. The burst size and latent period are estimated to be roughly 100-250 infectious units $cell^{-1}$ and < 96 h, respectively.

• ALGAE
• /
• 제22권4호
• /
• pp.287-295
• /
• 2007

Infection of free-living dinoflagellates by endoparasitic dinoflagellates of the genus Amoebophrya are thought to have significant impacts on host population dynamics and have long been proposed to be a potential biological agent for controlling harmful algal bloom (HAB). To understand the impact of Amoebophrya on particular host species, however, it is necessary to quantify aspects the parasites life cycle. Here we used cultures of Amoebophryahost systems from Jinhae Bay, Korea to determine, parasite generation time, and dinospore survival and infectivity. The proportion of host cells infected by Amoebophrya sp. changed sharply from 5% to 87% with increasing dinospore:host inoculation ratios. In the absence of H. triquetra, most free-living dinospores died within 72 hours and their ability to infect host cells decreased remarkably in a day. The relatively short free-living phase of Amoebophrya suggests that the spread of infections is most likely to occur during seasons of high host abundance, as that is when dinospores have the greatest chance of encountering host cells. Infection of host cells inoculated with dinospores during the day was higher than when inoculated during the night, suggesting that infection rates might be related to environmental light conditions and/or diurnal biological rhythm of host species. Total generation times of parasite strains from a thecate dinoflagellate Heterocapsa triquetra were nearly the same regardless of dinospore:host inoculation ratios, representing 54 ± 0.5 h in a 1:1 ratio and 55 ± 1.2 h in a 20:1 ratio. Dinospore production of Amoebophrya sp. infecting Heterocapsa triquetra was estimated to be 125 dinospores per a strain of Amoebophrya sp. There is a growing need to maintain a variety of host-parasite systems in culture and to examine their autecology under various environmental conditions. Such studies would be very helpful in understanding ecological role of these parasites, their overlooked importance in the flow of material and energy in marine ecosystem, and their practical use as biological control agents applied directly to areas affected by HAB.

• 환경생물
• /
• 제35권3호
• /
• pp.251-264
• /
• 2017

A study searching for unrecorded and taxonomically undescribed indigenous species has been conducted since 2006. Samples were collected from many sites in coastal waters and offshore in Korea as well as around Jeju Island. Since 2008 we have found 13 unrecorded species belonging to family Diplopsaliaceae, Heterocapsaceae, Kolkwitziellaceae, Protoperidiniaceae and Thoracosphaeraceae. The species are as follows, Preperidinium meunieri (2014), Heterocapsa ovata (2015), H. pseudotriquetra (2015), Diplopsalis lenticula (2008), Protoperidinium abei (2009), P. diabolus var. longipes (2010), P. depressum (synonym: P. parallelum (2008)), P. latispinum (2016), P. punctulatum (2010), P. solidicorne (synonym: P. spinosum (2010)), P. subpyriforme (2010), P. pacificum (2013), Scrippsiella hexapraecingula (2009) (note; The numbers in parenthesis refer to the year that the species was reported as unrecorded indigenous species by National Institute of Biological Resources, NIBR hereafter). Among these, 5 species were described as newly recorded species in Korean waters, and 8 were re-described in this study.

• 환경생물
• /
• 제31권3호
• /
• pp.213-224
• /
• 2013

새만금호는 만경강과 동진강에서 유입되는 담수를 통해 영양염을 지속적으로 공급받아 부영양이 가속화되고 있었다. 또한 담수 유입에 따라 구역별로 환경요인들이 차이를 보이고 있었다. 이러한 환경의 차이는 식물플랑크톤 군집의 출현양상의 변화를 가져오고 있었다. 새만금호의 부영양화된 수계에서 식물플랑크톤 군집은 개체수가 증가하고 종 다양성이 감소하고 있었으며, 와편모조류 등의 일부 종이 대발생을 일으키고 있었다. 특히 2009년에는 기존에 크게 출현하지 않았던 Heterocapsa triquetra, Karlodinium veneficum, Heterocapsa rotundata가 우점하여 새만금호 내부의 부영양화에 따른 수환경변화로 식물플랑크톤 군집에 변화가 나타났다. 이와 같이, 새만금호의 서식환경의 변화는 와편모조류의 적조발생 등 식물플랑크톤 군집의 환경 적응력과 연관하여 파악하여야 하며, 이를 위해서는 지속적인 모니터링이 필요하다.

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

• ALGAE
• /
• 제34권1호
• /
• pp.7-21
• /
• 2019

The genus Heterocapsa is one of the major dinoflagellate groups, with some of its species having worldwide distributions. However, prior to the present study, the phototrophic species Heterocapsa minima has been reported only from the northeast Atlantic Ocean. Recently, H. minima was found in the Korean waters, and a clonal culture was established. This culture was used to examine the morphology of the Korean strain H. minima HMMJ1604 through light and scanning electron microscopy, as well as for its genetic characterization. Furthermore, to determine the nationwide distribution of H. minima in Korea, its abundance was quantified in the waters of 28 stations in all four seasons in 2016-2018 using the quantitative real-time polymerase chain reaction method. The overall morphology of H. minima HMMJ1604 was very similar to that of the Irish strain H. minima JK2. However, the Korean strain had five pores around the pore plate, whereas the Irish strain had six pores. When properly aligned, the sequences of the large subunit and internal transcribed spacer regions of the ribosomal DNA of the Korean strain were identical to those of the Irish strain. This species was detected in the waters of 26 out of 28 stations, but its abundance was greater than $1.0cells\;mL^{-1}$ at 8 stations. The highest abundance of H. minima was $44.4cells\;mL^{-1}$. Although this species was found in all seasons, its abundance was greater than $1.0cells\;mL^{-1}$ when the water temperature and salinity were $10.9-25.0^{\circ}C$ and 17.5-34.1, respectively. To the best knowledge, the present study reported for the first time that H. minima lives in the Pacific Ocean and is widely distributed in the Korean waters.

• 한국해양학회지:바다
• /
• 제12권4호
• /
• pp.359-369
• /
• 2007

Amoebophrya는 숙주생물에 기생하여 이들을 단기간에 사멸시키는 내부기생성 진핵와편모류로서 숙주 특이성과 숙주 생물의 개체군 동태에 미치는 막대한 영향으로 인해 오래 전부터 유해적조생물에 대한 생물학적 제어 가능성이 제기되었다. 그 동안 숙주 - 기생생물 시스템 배양이 어려워 수 십 년간 연구가 답보상태에 빠졌으나, 최근 소수 종의 숙주 - 기생생물 시스템 배양에 성공하여 새로운 전기를 맞았다. 본 연구는 Amoebophrya가 숙주생물의 개체군 동태에 미치는 영향을 탐색하기 위한 예비연구로서 진해만에서 2년 동안 숙주 와편모류에 기생하는 Amoebophrya spp.의 출현 시기를 관찰하고 Heterocapsa triquetra의 숙주 - 기생생물 시스템 배양을 통하여 이들의 숙주특이성을 평가하였다. 연구기간 동안 9종의 와편모류, Akashiwo sanguinea, Ceratium fusus, Dinophysis acuminata, Heterocapsa triquetra, Oblea sp., Prorocentrum minimum, P. triestinum, Scrippsiella spinifera, S. trochoidea에서 내부기생 Amoebophrya에 의한 감염을 관찰하였으며, 이 중 무각 와편모류 A. sanguinea와 유각 와편모류 H. triquetra 2종에 대한 숙주 - 기생생물 시스템의 실내 배양체 확립에 성공하였다. 연구해역이나 이전에 Amoebophrya가 관찰 또는 보고된 6종의 숙주생물에 H. triquetra에 기생하는 Amoebophrya를 교차 접종하여 이들이 다른 와편모류보다 자기 숙주에 매우 큰 선호도를 가짐을 확인하였다. 앞으로도 우리나라 주변 해역에 출현하는 기생성 와편모류 Amoebophrya를 탐색하여 다양한 숙주 - 기생생물 시스템 배양체를 지속적으로 확보할 필요가 있다. 이러한 기생성 와편모류 Amoebophrya에 대한 생리 생태 특성 연구를 통하여 해양생태계 내에서 그들의 역할을 이해하고 생물학적으로 적조를 제어하는 데에 크게 도움을 얻을 수 있다.

• 한국해양학회지
• /
• 제25권2호
• /
• pp.106-116
• /
• 1990

본 연구는 마산만 일대의 와편모조류 군집의 구조와 동태 및 계절적 천이 그리고 환경요인과의 상호관계를 포괄하고자 1986년 4월부터 1987년 3월까지 일년 동안 제정 된 6개 정점에서 매월 실시하였다. 와편모조류에 현존량의 분포는 44-2,798,900 cella-/l, 저층에서 52-165,714 cells/l로서 층별, 월별, 정점별 차이가 매우 크게 나 타났으며 대발생(500,000 cells/l)의 양상은 표층의 4월부터 8월까지로써 춘·하계에 집중되어 있으며 정점별 외만보다 내만의 정점에서 더욱 두드러지게 나타났다. 출 현종의 세포크기에 의한 현존량의 분포를 조사한 결과 대부분의 우점종이 20-40 um 크 기로 대표할 수 있었으며, 이들 종류들은 내만에 더욱 우점하는 특이한 경향을 나타내 었다. 출현종 중 우점종은 육속 구종 이며, 우점종의 계절적인 천이는 Gyrodinium fissum이 년중 전 계절에 걸쳐 우점하였으며 5월에 Scrippsiellat trochoidea가 6월 에서 9월까지 Prorocentrum minimum, Protoperidinium bipes가 9월에서 12월까지 Ceratium fusus, Prorocentrum micans, Prorocentrum triestinum이 12월에 4월까지 Heterocapsa triquetra가 우점하는 천이의 양상을 나타내었다. 와편모조류의 현존량의 변화와 분석된 환경요인과의 상관관계를 단계식 중회귀식에 의해 분석한 결과 pH, 연 분 투명도, 실소등이 영향을 미치는 것으로 나타났다.