• ALGAE
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• 제37권2호
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• pp.123-133
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• 2022

Genetic diversity and distribution patterns of marine macroalgae are increasingly being documented in Southeast Asia. These studies show that there can be significant levels of genetic diversity and isolation between populations on either side of the Thai-Malay Peninsula. Bostrychia tenellla is a common filamentous red seaweed in the region and the entity is represented by at least two cryptic species. Despite being highly diverse and widespread, genetic variation and population structure of this species complex remains understudied, especially around the Thai-Malay Peninsula. We analyzed genetic diversity and inferred the phylogeographic pattern of specimens identified as B. tenella using the plastid RuBisCo spacer from samples from the Andaman Sea and the Gulf of Thailand. Our genetic analysis confirmed the occurrence of the two cryptic B. tenella species (B and C) along both coasts. Cryptic species B was more common in the area and displayed higher genetic diversity than species C. Historical demographic analyses indicated a stable population for species B, but more recent population expansion for species C. Our analyses also revealed that both cryptic species from the Andaman Sea possessed higher genetic diversity than those of the Gulf of Thailand. We also detected moderate to high levels of gene flow and weak phylogeographic structure of cryptic species B between the two coasts. In contrast, phylogeographic analysis showed genetic differences between populations of both cryptic species within the Andaman Sea. Overall, these results suggest that cryptic B. tenella species around Thai-Malay Peninsula may have undergone different demography histories, and their patterns of genetic diversity and phylogeography were likely caused by geological history and regional sea surface current circulation in the area.

• ALGAE
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• 제38권2호
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• pp.127-139
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• 2023

Cryptic stages of diverse macroalgae present in natural substrata, "the bank of microscopic forms", were isolated into clonal cultures and identified based on both morphological characteristics and DNA barcoding. Approximately 120 clonal isolates from 308 natural substratum samples were collected from the entire coastline of Kuwait. Amongst these isolates, 77 (64%) were identified through DNA barcoding using the nuclear ribosomal small subunit, RuBisCO spacer (ITS2, tufa, rbcL, psaA, and psbA) and sequencing. Twenty-six isolates (34%) were identified in the division Chlorophyta, 18 (23%) as Phaeophyceae, and 33 (43%) as Rhodophyta. For all DNA sequences in this study, species-level cut off applied was ≥98% homology which depend entirely on the markers used. Three putative new records of Chlorophyta new for the Arabian Gulf were made: Cladophora laetevirens (Dillwyn) Kützing, Ulva torta (Mertens) Trevisan and Ulvella leptochaete (Huber) R. Nielsen, C. J. O'Kelly & B. Wysor in Nielsen, while Cladophora gracilis Kützing and Ulva ohnoi M. Hiraoka & S. Shimada are new records for Kuwait. For Phaeophyceae, Ectocarpus subulatus Kützing and Elachista stellaris Areschoug were new records for the Gulf and Kuwait. In the Rhodophyta, Acrochaetium secundatum (Lyngbye) Nägeli in Nägeli & Cramer, Ceramium affine Setchell & N. L. Gardner, Gelidium pusillum var. pakistanicum Afaq-Husain & Shameel and Dasya caraibica Børgesen are new records for the Gulf and Kuwait, while the red alga Stylonema alsidii (Zanardini) K. Drew is a new record for Kuwait. Several isolates identified corresponded to genera not previously reported in Kuwait and / or the Arabian Gulf, such as Porphyrostromium Trevisan, a new genus from the Bangiales, and two unidentified species for the Planophilaceae Škaloud & Leliaert. The isolates cultivated from substrata enhance understanding of the marine macroalgal diversity in the region and confirmed that the Germling Emergence Method is suitable for determining the actual diversity of a given study area through isolation from cryptic life-history phases.

• ALGAE
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• 제29권2호
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• pp.137-152
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• 2014

Mixotrophic protists play diverse roles in marine food webs as predators and prey. Thus, exploring mixotrophy in phototrophic protists has emerged as a critical step in understanding marine food webs and cycling of materials in marine ecosystem. To investigate the feeding of newly described mixotrophic dinoflagellate Ansanella granifera, we explored the feeding mechanism and the different types of species that A. granifera was able to feed on. In addition, we measured the growth and ingestion rates of A. granifera feeding on the prasinophyte Pyramimonas sp., the only algal prey, as a function of prey concentration. A. granifera was able to feed on heterotrophic bacteria and the cyanobacterium Synechococcus sp. However, among the 12 species of algal prey offered, A. granifera ingested only Pyramimonas sp. A. granifera ingested the algal prey cell by engulfment. With increasing mean prey concentration, the growth rate of A. granifera feeding on Pyramimonas sp. increased rapidly, but became saturated at a concentration of $434ngCmL^{-1}$ (10,845 cells $mL^{-1}$). The maximum specific growth rate (i.e., mixotrophic growth) of A. granifera feeding on Pyramimonas sp. was $1.426d^{-1}$, at $20^{\circ}C$ under a 14 : 10 h light-dark cycle of $20{\mu}Em^{-2}s^{-1}$, while the growth rate (i.e., phototrophic growth) under similar light conditions without added prey was $0.391d^{-1}$. With increasing mean prey concentration, the ingestion rate of A. granifera feeding on Pyramimonas sp. increased rapidly, but slightly at the concentrations ${\geq}306ngCmL^{-1}$ (7,649 cells $mL^{-1}$). The maximum ingestion rate of A. granifera feeding on Pyramimonas sp. was 0.97 ng C $predator^{-1}d^{-1}$ (24.3 cells $grazer^{-1}d^{-1}$). The calculated grazing coefficients for A. granifera feeding on co-occurring Pyramimonas sp. were up to $2.78d^{-1}$. The results of the present study suggest that A. granifera can sometimes have a considerable grazing impact on the population of Pyramimonas spp.

• 해양환경안전학회지
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• 제26권6호
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• pp.674-680
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• 2020

적조가 처음 시작되는 해역을 조기에 파악하기 위하여 Quantitative real-time PCR (qPCR)을 경남해역 적조현장에 활용하였다. 2019년 경남해역을 대상으로 Cochlodinium polykrikoides를 qPCR로 정량분석한 결과, 6월 초에 저밀도로(0.0015~0.0058 cells mL^-1) 검출되기 시작하여 8월 중순에는 최대 0.163 cells mL^-1 밀도로 증가하였고, 주로 남해도 주변에서 높게 검출되었다. 8월 말에는 현미경 검경으로 남해도 주변에서 높게 출현함이 확인되었고(최대 24 cells mL^-1), 9월 2일에는 남해도에서 적조주의보가 발령되었고(최대 200 cells mL^-1), 9월 1일에는 최대 12,000 cells mL^-1까지 남해도 해역에서 발생하였다. 위 결과는 극미량의 C. polykrikoides이 적조발생 전에 남해도에서 검출되었고 이후 같은 해역에서 적조가 발생되었음을 보여준다. 이는 qPCR이 극미량의 C. polykrikoides을 조기검출하는데 유용한 방법임을 보여준다.

• 한국수산과학회지
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• 제19권3호
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• pp.265-273
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• 1986

본 연구는 한국 남해안 동부해역의 해조군집 특성을 정량적으로 분석하고, 그 변동을 파악하기 위하여 일차적으로 이 해역을 대표 할 수 있다고 보여지는 경남 통영군 욕지면 연화도에 선정한 8개 지점에서 1984년 12월부터 1986년 1월사이에 수행되었고, 그 결과는 다음과 같았다. 1. 출현 해조류는 남조류 2종($1.8\%$), 녹조류 18종($15.8\%$), 갈조류 25종($21.9\%$) 그리고 홍조류 69종($60.5\%$)으로 모두 114종이었다. 2. 홍조류 종수에 대한 갈조류 종수의 비 (R/P 값)은 2.8로 남해안 연안쪽보다 높게 나타났다. 3. 해조류의 기능형군별 구성비는 계절적으로는 봄 겨울에는 사상형과 막상형이 우세하고, 여름과 가을에는 직립분기형과 다육질형이 우세하였다. 그리고 지점별로는 파도가 적은 내만쪽에서 막상형과 각상형이 우세하고, 파도가 강한 쪽에서 직립분기형과 다육질형이 우세하였다. 4. 군집의 유사도 분석 결과, 유사도 $30\%$ 수준에서 봄에는 5개군, 여름, 가을 및 겨울에는 3개군으로 나타났고, 이들은 파도의 강약, 계절풍의 영향정도에 따른 특성을 갖는 것으로 추정되었다. 5. 전 조사기간을 통하여 전 지점에서 중요도 10이상인 종은 Porphyra suborbiculata (30.1), Corallina pilulifera (27.8), Hizikia fusiforme (27.7), Sargassum thunbergii, (27.5), Undaria pinnatifida (22), Ishige okamurai (20.6), Chondria crassicaulis (20), Ulva pertusa (16), Pseudulvella consociata (15.7), Urospora penicilliformis (15), Sargassum sagamianum (14.9), Caulacanthus okamurai (12.8), Gloiopeltis furcata (12.7), Sargassum micracanthum (11.7), Myelophycus simplex (11.2) 이었고, Melobesioideae가 25.7이었다. 6. 무절석회조 순군집의 빈도 및 피도는 각각 $44.6\%$ 및 $75\%$였고, 무절석회조와 다른 해조가 혼생하는 군집의 빈도 및 피도는 각각 $55.4\%$ 및 $65.8\%$로서 혼생하는 군집의 피도가 약간 낮았다. 7. 무절석회조와 다른 해조류가 혼생하는 군집의 출현빈도나 피도가 높은 종은 Corallina pilulifera, Gelidium amansii, Sargassum sagamianum, S. thunbergii, Hizikia fusiforme, Laurencia spp. 등으로 기능형으로는 주로 직립분기형이나 다육질형이었다. 8. 점심대지역에서의 무절석회조의 높은 피도율은 명확하지는 않으나 식해의 영향 때문인 것으로 추정되었다.

• 환경생물
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• 제31권3호
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• pp.213-224
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• 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.

• 한국미생물·생명공학회지
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• 제45권3호
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• pp.243-249
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• 2017

An agar-degrading bacterium, designated as the GNUM08123 strain, was isolated from samples of red algae collected from the Yongil Bay near East Sea, Korea. The isolated GNUM08123 strain was gram-negative, aerobic, motile, and beige-pigmented, with $C_{16:0}$ (25.9%) and summed feature 3 (comprising $C_{16:1}{\omega}7c/iso-C_{15:0}2-OH$, 34.4%) as its major cellular fatty acids. A similarity search based on the 16S rRNA gene sequence revealed that it belonged to class Gammaproteobacteria and shared 97.7% similarity with the type strain Vibrio chagasii $R-3712^T$. The DNA G+C content of strain $GNUM08123^T$ was 46.9 mol%. The major isoprenoid quinone was ubiquinone-8. The results of DNA-DNA relatedness and 16S rRNA sequence similarity analyses, in addition to its phenotypic and chemotaxonomic characteristics, suggest that strain GNUM08123 is a novel species within genus Vibrio, designated as Vibrio sp. GNUM08123. Agarase production by strain GNUM08123 was induced by agar and sucrose, but was repressed probably owing to carbon catabolite repression by glucose and maltose.

• 한국양식학회지
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• 제2권1호
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• pp.1-7
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• 1989

양식 해조류인 큰방사무늬김에 대한 조직배양을 종자 세포 보존 및 장차 세포수준의 내저 염성 품종개량을 목적으로 시도하였다. 김 엽체의 영양 성장부위를 무균적으로 PES-한천배지 상에 배양함으로서 callus의 형성을 유도하였으며 이 적갈색의 연약한 callus를 $16^{\circ}C$에서 12시간 주기로 2000 lux의 형광등 하에서 1개월마다 이식하면서 배양하였다. 총 탄수화물 및 단백질 함량을 측정하였으며, 최적 배양온도는 $14^{\circ}C\~18^{\circ}C$였다. PES-한천배지 상에서 $2.0\%$의 NaCl 농도가 callus의 성장에 가장 우수하였다.

• 한국수산과학회지
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• 제47권5호
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• pp.522-526
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• 2014

Pyropia, economic red algae species, have been cultivated in Korea (referred to as 'gim'), Japan ('nori'), and China ('zicai') for over 300 years. Vegetable seaweed Pyropia species are sold in the public markets in various forms as commercial seafoods. In Korea, two kinds of Pyropia seafood made with species of Pyropia and Ulva (sea lettuce, referred to as 'parae') are also sold. These are referred to as 'parae-gim' (with Pyropia spp. and U. linza) and 'gamtaegim' (with Pyropia spp. and U. prolifera). There is currently no method for identifying the seaweed species that comprise Pyropia seafood products. Therefore, we developed novel molecular markers to identify Ulva species in commercial Pyropia seafoods. Based on rbcL molecular markers, we identified informative characteristics to discriminate U. linza and U. prolifera as seafood ingredients. Moreover, PCR with 3'-end mismatch primers successfully isolated the specific rbcL sequences of U. linza and U. prolifera from Pyropia seafoods. Therefore, our novel molecular markers will be useful for identifying the ingredient species of commercial seafoods.

• 한국수산과학회지
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• 제47권3호
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• pp.274-282
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• 2014

We examined seasonal variation in the structure of marine macroalgal communities at five sites around the Byeonsan Peninsula, Korea, from January to October 2011. Sixty eight species were identified, including 11 green, 17 brown and 40 red algae. Species richness was highest at Gyeokpo (51 species) followed by Sambal (47), Gosapo (34), Byeonsan (33), and Habgoo (18). Seaweed biomass ranged from 12.98 to 145.33 g dry $wt/m^2$, with maximum and minimum biomasses at Gyeokpo and Habgoo, respectively. Sargassum thunbergii was the representative alga species occupying 47.89% of the total biomass. The dominant seaweeds were S. thunbergii, Corallina pilulifera, Ulva spp, Gracilaria vermiculophylla, and Carpopeltis affinis. No distinctive vertical distribution of seaweeds was found because S. thunbergii, Ulva spp, and G. vermiculophylla were all distributed from high to low shore. Community indices were as follows: dominance index (DI), 0.44-0.61; richness index (R), 6.27-10.35; evenness index (J'), 0.38-0.59; and diversity index (H'), 1.48-1.71. Gyeokpo had the most biomass and highest species richness, and the lowest percentage of Ulva species. However, species richness declined at Gyeokpo, from 78 to 51 species within 10 years, implying that eutrophication and sedimentation from Mankyeong and Dongjin rivers have reduced the stability of seaweed communities.