Jeong Ha Kim

ACCLIMATION OF PROROCENTRUM MINIMUM (DINOPHYCEAE) TO PROLONGED DARKNESS BY USE OF AN ALTERNATIVE CARBON SOURCE FROM TRIACYLGLYCERIDES AND GALACTOLIPIDS

The dinoflagellate Prorocentrum minimum (Pavillard) Schiller is known to be a major bloom‐causing microalga in the southern ocean of the Korean peninsula. The acclimation of this alga to darkness for 10 days was investigated by analyzing the content of various lipids, such as phospholipid (PL), galactolipid (GL), and triacylglyceride (TAG). Actively growing cultures of the alga under normal growth conditions (14:10 h LD [light:dark] cycle) were transferred to a growth chamber under conditions of no light and no carbon sources in the medium, and the culture was continued for another 10 days. The results showed that the content of TAG and GL decreased gradually during dark incubation, whereas the total PL content changed little; PC, PE, and PG decreased; and PS, PA, and PI increased. An increase in the activity of β‐oxidation and isocitrate lyase (ICL, a glyoxylate cycle enzyme) paralleled the decrease of TAG and GL. These observations strongly suggested that TAG and GL were utilized as alternative carbon sources by the cells under the prolonged dark cultivation. Light treatment of the cells cultivated in the dark for 10 days allowed them to attain the lipid composition that was observed in cells grown in light. These results strongly suggested that the cells maintained their metabolic integrity without unrecoverable cellular damages or cell death during 10 days of dark cultivation.

Community Structure of Benthic Marine Algae at Daejin and Jukbyeon on the Mid-East Coast of Korea

The species composition and variation of benthic marine algae at Daejin and Jukbyeon on the mid-east coast of Korea were investigated seasonally from August 2006 to April 2007. As a result, the total of 85 species, including 8 chlorophytes, 26 phaeophytes, 50 rhodophytes and 1 sea grass were identified. 52 species were found at Daejin and 74 species at Jukbyeon. Dominant species in importance value were Corallina pilulifera, Chondrus ocellatus, melobesioidean algae, Sargassum horneri, Sargassum yezoense and Phyllospadix japonica at Daejin, and Corallina pilulifera, melobesioidean algae, Phyllospadix japonica, Acrosorium polyneurum, Sargassum siliquastrum and Hizikia fusiformis at Jukbyeon, respectively. The vertical distribution of algae were characterized by Corallina pilulifera, Hizikia fusiformis, Sargassum spp. (S. siliquastrum, S. yezoense) and Symphyocladia latiuscula at intertidal zone, Sargassum spp. (S. horneri, S. serratifolium, S. yezoense), melobesioidean algae, Phyllospadix japonica and Corallina pilulifera at 1 m depth, melobesioidean algae, Phyllospadix japonica and Sargassum spp. (S. horneri, S. yezoense) at 5 m depth and melobesioidean algae, Phyllospadix japonica and Sargassum spp. (S. horneri, S. micracanthum, S. yezoense) at 10 m depth.

Temporal Variations in Seaweed Biomass in Korean Coasts: Woejodo and Jusamdo, Jeonbuk

해조류는 이산화탄소(CO2)와 태양에너지를 이용하여 광 합성을 하는 해양생태계의 일차생산자로서 어류 또는 무척 추 동물을 포함하여 다양한 해양생물의 먹이와 산란장, 생육 장 및 은신처 등 생태학적으로 중요한 역할을 수행하여 먹이 사슬의 상위생물량을 조절하는 기반을 제공한다(Worm et al. 2000; 김과 최 2004; 이 등 2007; 김과 신 2007). 이외에도, 해조류는 부영양화 해역에서 영양염을 제거하는 생물정화자 로서의 기능(Hemminga et al. 1999)과 부착 동∙식물의 착 생기질로 사용되므로 해양생태계 생물다양성에 지대한 영향 을 준다(McCall et al. 1999). 또한, 해조류는 아가, 알긴산 및 캐러기난과 같은 해조산업의 원료와 식용 및 약용으로 사용 되고 있으며(Tseng 1981; Oh et al. 1990), 최근에는 유가 상 승과 온실가스의 주범인 화석연료를 대체할 바이오에탄올의 원료와 온실가스인 CO2를 제거하는 나무를 대체할 종이의 원료(예, 우뭇가사리)로도 관심을 받고 있다(Bastianoni et al. 2008). 따라서, 해조류의 생태적 기능, 환경정화 기능, 유용 종의 생물량, 바이오연료와 종이원료로서의 가능성 확인 및 해양 생태계의 안정성을 파악하기 위해서는 연안에 서식하 는 해조류의 생물량과 이들을 구성하는 주요종의 실태를 파 Algae Volume 23(4): 335-342, 2008

Temporal Variations of Seaweed Biomass in Korean Coasts: Daejin, Gangwondo

Seaweed biomass was estimated using a nondestructive sampling method in the rocky intertidal and subtidal zone in Daejin on the mid-east coast of Korea from August 2006 to April 2008. Seasonal sampling were done at the depth of 0, 1, 5, 10 m using 50 x 50 cm quadrat. A total of 95 species, including 11 chlorophytes, 26 phaeophytes, 57 rhodophytes and one sea grass were identified. Mean biomass was comprised of 1,292 g wet wt m and the biomass values varied seasonally from 904 g to 1,945 g. Dominant species in biomass were Sargassum spp. (S. horneri, S. yezoense), Corallina pilulifera, Phyllospadix japonica, Symphyocladia latiuscula, Hizikia fusiformis, Codium arabicum and Chondrus ocellatus at Daejin. The vertical distribution of algae were characterized by Corallina pilulifera, Symphyocladia latiuscula, Sargassum spp. (S. confusum, S. yezoense), Hizikia fusiformis and Grateloupia elliptica at intertidal zone, Sargassum spp. (S. fulvellum, S. horneri, S. yezoense), Phyllospadix japonica, Codium arabicum, Undaria pinnatifida and Corallina pilulifera at 1 m depth, Sargassum spp. (S. horneri, S. micracanthum, S. yezoense), Phyllospadix japonica, Grateloupia elliptica, Gelidium amansii and Codium arabicum at 5 m depth and Phyllospadix japonica, Codium arabicum, Sargassum spp. (S. horneri, S. micracanthum, S. yezoense) and Undaria pinnatifida at 10 m depth.

Species Composition and Biomass of Intertidal Seaweeds in Chuja Island

The marine benthic algal flora and biomass of Chuja Island, southern coast of Korea, was investigated. The collections of intertidal marine algae were made at two sites, Yecho of Hachujado and Hupo of Sangchujado, from October 2006 to July 2007. A total of 162 species, including 15 green, 47 brown and 100 red algae, were identified in this study. The occurrence of species according to season was abundant during spring to summer and less in autumn. The vertical distribution of intertidal zone in Chujado was characterized by Gloiopeltis spp., Myelophycus simplex, Ishige okamurae, Chondrus ocellatus, Grateloupia elliptica, Hizikia fusiformis and Sargassum spp. The average biomass of macroalgae was measured as 400 g wet wt m. The dominant species based on the biomass were Sargassum yezoense, S. coreanum and Hizikia fusiformis. ESG II (ecological state group) as an opportunistic species, including sheet form, filamentous form, and coarsely branched form, occurred 85.8% in the intertidal seaweeds. These results provide a baseline for future monitoring studies in the Chuja Island.

Efficient isolation of intact RNA from the soft coral Scleronephthya gracillimum (Kükenthal) for gene expression analyses

Abstract A rapid, simple and efficient method to extract RNA from the adult polyps of a soft coral, marine cnidarian, Scleronephthya gracillimum (Kükenthal), was developed in this study. The highest yield and purity of RNA was obtained with the lysis solution containing 35 mM EDTA, 0.7 M LiCl, 7.0% SDS, and 200 mM Tris‐Cl (pH 9.0). Approximately 40 μg of total RNA was extracted from 200 mg of liquid nitrogen‐pulverized polyp tissue. The ratio of absorbance at 260 nm and 280 nm ranged from 1.8 to 2.0. The results of the reverse transcription polymerase chain reaction (RT‐PCR) with β‐actin gene specific primers and Northern blot analysis using the same gene probe revealed that the RNA extracted by our method had high quality, and was sufficient for subsequent molecular biological analyses. This method was effective for RNA extraction from other soft coral species which belong to the genus Dendronephthya.

The importance of substratum and elevation in recruitment and persistence of ulvoid algal blooms on rocky intertidal shores of the southern Korean coast

Abstract Patterns in the recruitment, distribution, and persistence of three Ulva species, which can form green tides, were investigated in relation to surface roughness using artificial substrates on intertidal rocky shores of the southern coast of Korea. The vertical distributions of Ulva pertusa, Ulva linza, and Ulva compressa were well separated: U. compressa usually dominated in the upper zone and U. pertusa and U. linza in the lower zone. Ulva pertusa recruitment was observed during autumn, when inorganic nitrogen concentrations in the surface water column were highest. However, the recruitments of U. linza usually occurred during early winter and spring and that of U. compressa during summer–autumn. Ulva pertusa showed highest settlement on rough surfaces in both zones, whereas this pattern only appeared in the upper zone for U. linza and U. compressa. These results indicate that settlement patterns may be affected by desiccation in the upper zone and waves in the lower zone. Once blooms occurred, U. pertusa persisted for about twice as long as the other two Ulva species, suggesting that U. pertusa played an important role in community change. This is the first documentation of persistence periods related to recruitment in bloom-forming green macroalgae.

Changes in gene expression in the brown alga Undaria pinnatifida (Harvey) Suringar (Laminariales, Pheophyceae) between natural populations

Genes involved in defense mechanisms can be used as efficient biomarkers of physiological changes in organisms caused by both endogenous and exogenous stress. Thus, the expression levels of such genes serve as a critical ‘early warning system’ for the environmental assessment and health of biological organisms. In this study, the transcription levels of Hsp70 and vBPO in Undaria pinnatifida sporophytes were quantitatively compared between two distinct natural populations collected from uncontaminated Mijo (Namhae, Korea) and industrially-polluted Myodo Is. (Yeosu, Korea) in order to verify their potential as biomarker genes and the applicability of this macroalga for assessing the health status of a local marine ecosystem. The results found that the two tested genes were highly expressed in the Myodo population. The results suggest that U. pinnatifida itself and the selected two genes could be applicable to monitoring of marine environments in coastal regions.