• Title/Summary/Keyword: Marine Organisms

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Endobiotic microalgae in molluscan life

  • Sokolnikova, Yulia
    • Fisheries and Aquatic Sciences
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    • v.25 no.10
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    • pp.499-516
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    • 2022
  • Endobiotic microalgae inhabit various groups of organisms, including bivalves. In this group, the association between the giant molluscs Tridacna and Symbiodinium is one of the most recognizable. This consortium allows hydrobionts to survive in oligotrophic waters by regulating their metabolism. The available research has provided an understanding of the interaction and adaptation of these symbionts, but the problem of the beginning of the formation of these relationships remains unresolved. In the case of Tridacninae, symbiosis is essential for the survival of bivalves, in contrast to representatives of the Mytilidae and the Coccomyxa found in them. A few works devoted mainly to the morphological aspects of invasion have shown that endobiont causes inflammation and pathology. Having data to clarify the exact "diagnosis" of the interaction of these organisms is not enough. It is possible that the relationship between bivalves and Coccomyxa is in the early stages of being established, which may lead to mutualism or parasitism in the future. We assume that the analysis of works on the symbiosis of Symbiodinium and bivalves will facilitate the course of research for the less studied Coccomyxa and their hosts. By postulating the Coccomyxa represent a unique evolutionary model for the formation of a symbiotic system, it is possible to use this system to study the interaction of organisms during their initial contact. The identified signalling pathways and mechanisms that allow the photobionts to evade host immunity can be useful for constructing new forms of symbiosystems.

Marine Biodiversity Study and Biotechnology Exploitation in China

  • Liu, J.Y.
    • Journal of Marine Bioscience and Biotechnology
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    • v.1 no.1
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    • pp.40-47
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    • 2006
  • Large scale marine biodiversity studies in China have been carried out for more than half a century since the founding of the Institute of Oceanology, CAS, in 1950. Through a series of coastal and multi-disciplinary oceanographic investigations in the shelf seas and biodiversity studies since the late fifties, a total of 20,278 species of marine biota have been recorded upto 1994. Recent intensive studies have further revealed the richness of marine biota of the China seas,a great number of marine species have been found and many new taxa established. The total species number of main biotic groups increased about 50 % of that estimated in 1994. The results have promoted the fast development of China's marine fisheries, medicine (drug) and biodiversity research, and attracted many scientists, particularly bio-technologists, to join their studies. Environmental deterioration and human activity strongly stressed the sustainable development and conservation of marine bio-diversity, and resulted in the increase of end angered species as record ed in the new published ${\ll}$China Species Red List${\gg}$ with the threatened category of species assessed by adopting the new IUCN criteria. To further reveal the high diversity and their history, present status and future of marine organisms existed in the world ocean, an international Project ${\ll}$Census of Marine Life (CoML)${\gg}$ was established in 2000 in the USA. Scientists predicted that 2 to 3 times of numbers of the known species will possibly be found in various marine habitats, particularly the abyssal ocean. The Research Plan and the Projects were briefly introduced, and the relationship between marine biodiversity and biotechnology was discussed. The Project planned to apply new and high techniques and new equipments on board research vessel and in laboratory. Brief review of recent advances of Chinas' marine biodiversity and biotechnology studies indicated that fascinate results have been achcieved; but further effort should be made to promote the continuous advance of our basic researches and their application in related production and maintain sustainable development.

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Seasonal Dynamics of Marine Benthic Communities in Intertidal Zone of Gwangyang Bay, Southern Coast of Korea

  • Yoo, Jong-Su
    • Ocean and Polar Research
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    • v.25 no.4
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    • pp.519-528
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    • 2003
  • Species composition and community structure of marine benthic community were studied in the intertidal zone of Jijindo Island, Gwangyang Bay. A total of 85 species of benthic marine plants including the 5 Cyanophyta, 9 Chlorophyta, 13 Phaeophyta, 56 Rhodophyta and 2 Magnoliophyta that were listed. The community structure was represented by Gelidium divaricatum in the upper zone, Celidium divalicatum and Ulva pertusa in the middle, and Ulva pertusa, Chondria crassicaulis, Chondracanthus intermedia and Sargassum thunbergii in the lower intertidal zone. The dominant species in the rnscro-zoobenthic community were Chthamalux challengeri in the upper and middle, Littorina brevicula between the upper and middle, and Mytilus edulis and Crassostrea gigas in the middle and lower intertidal zones. The economic benthic organisms such as Undaria pinnatifida, Mytilus edulis, and Crassostrea gigas found in the lower intertidal zone were frequently disturbed due to their collection by local resident. Therefore, it is necessary to record the correct information pertaining to these cases. The species diversity indices estimated kom different sources were quite different. They were 2.22 derived from frequency, 1.67 based on coverage, 2.17 based on sum of frequency and coverage and 2.04 derived from importance value. Species diversity and number of algal species in Gwangyang Bay have noticeably decreased, compared with their previously reported status. It is estimated that their decreases were caused by changes in the marine environment, especially pertaining to the polychaete community resulting from reclamation and dredging activity undertaken for the industrial development.

Prediction of Effect Zone for Marine Organisms Using Distance Attenuation Equations for Oceanic Noise (수중소음 거리감쇠 특성식을 이용한 해양생물 피해영향범위 예측)

  • Ha, Jeong-Min;Lee, Jong-Myeong;Lee, Jeong-Hoon;Gu, Dong-Sik;Choi, Byeong-Keun
    • Journal of Ocean Engineering and Technology
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    • v.26 no.2
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    • pp.14-19
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    • 2012
  • There are insufficient data to consider the effect zone for the marine life of coastal fisheries, because no standard has been defined for the sound level of marine life. In this study, equations for distance attenuation were used to determine the effect zone for oceanic noises. A reference noise level was divided into 4 parts to consider the characteristics of the fishes, and the effect zone of each reference noise level was determined. To increase the reliability of the effect scope, approximately 100 repetitions of blasting work split into several parts by the boring depth, the sound level of the source caused by an increase in weight, and the effect zone were calculated using the prediction equation. According to the prediction, the maximum distance of the effect zone was 4.92 km.

Effects of Environmental Factors on the Growth of Gametophytes and Young Sporophytes of Eisenia bicyclis (Kjellman) Setchell (대황(Eisenia bicyclis) 배우체와 아포체의 생장에 미치는 환경 인자의 영향)

  • Lee, Min-Jeong;Kim, Nam-Gil
    • Journal of Marine Bioscience and Biotechnology
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    • v.12 no.2
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    • pp.115-122
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    • 2020
  • Eisenia bicyclis, a perennial macroalga is a primary producer of in the ocean, It has been identified as a key species that plays a vital role in maintaining the ecosystem stability. Also, it is an important target in marine afforestation projects and useful marine organisms. In addition, E. bicyclis is used as a health food for humans. This study investigated the effect of water temperature, light (photon irradiance), and duration of light (photoperiod) on the growth of gametophytes and young sporophytes of E. bicyclis. The germination and growth of the zoospores of E. bicyclis were examined at five temperatures (5℃, 10℃, 15℃, 20℃ and 25℃), four intensities of photon irradiance (10, 20, 40, and 80 μmol m-2s-1), and photoperiods (14:10 and 10:14 light/dark cycles). The zoospores released from mature plant germinated into the gametophytes under all experimental conditions. The gametophytes were able to grow at water temperature 5℃-25℃ and mature at 10℃-20℃. The optimal range of water temperature for the maturation of the gametophyte was 15℃-20℃. At 25℃, E. bicyclis gametophytes grew rapidly but did not mature. The optimal culture conditions for the growth of young sporophytes grew slowly in low temperature and photon irradiances.

MICROMORPHOLOGICAL ASPECTS OF HARDWOODS DETERIORATED IN THE SEA-WATER FROM WRECKED SHIP'S TIMER (수침목재의 재질분석에 관한 연구-미시형태적 변화를 중심으로)

  • KIM, Yoon-Soo;CHOI, Kwang-Nam
    • 보존과학연구
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    • s.7
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    • pp.246-264
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    • 1986
  • Micoromorphological alterations of sea-waterlogged woods by marinemicro-oragnisms were investigated by the light and scanning electron microscopy as a part of serial investigations on the shipwrecked materials which were excavated at the sea shore of Wando-Kun, southern coast of Korea in 1984.Deterioration of sea-waterlogged wood by marine microorganisms were varied with the wood species. The degree of deterioration even in the same wood specieswas different according to the part where it was in mud of sea-water. However, the resistance of Torreya nucifera over the marine organisms was marked. Deterioration in cell wall may be classified into three types; thinning of cell wall, separation of secondary wall from compound middle lamella and tunneling of cell wall. Thinning and separation were frequently observed, while the tunneling was rare. Among the wood cell elements of hardwoods, vessel wall was the least deteriorated. The difference degree of degradation of cell wall constituents and the accumulation of inorganic substances in cell lumen indicate that some factors to be considered for the conservation treatment were discussed. The kinds of marine microorganisms invading and/or inhabiting in wrecked wooden ship were also discussed.

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Antifouling Activity of Coumarin and its Derivatives Isolated from the Cinnamon Tree Cinnamomum loureiroi (계피식물(Cinnamomum loureiroi)에서 분리한 coumarin과 유도체의 방오효과)

  • Kim, Young Do;Shin, Hyun Woung;Cho, Ji Young
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.46 no.1
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    • pp.53-58
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    • 2013
  • The active antifouling compounds coumarin and its derivatives were isolated from the cinnamon tree Cinnamomum loureiroi. The antifouling activities were determined using representative soft fouling organisms: the seaweed Ulvapertusa and diatom Navicula annexa. The chemical constituents with antifouling activities were identified as coumarin, hydroxylcoumarin, coumaric acid, and cinnamaldehyde by interpreting nuclear magnetic resonance, and high-resolution mass spectroscopy data. These compounds were isolated from 1.09 g of crude Cinnamomum sp. methanol extract, yielding approximately 18.4, 6.3, 9.8, and 14.7 mg of coumarin, hydroxylcoumarin, coumaric acid, and cinnamaldehyde, respectively. The compounds inhibited U. pertusa zoospores with $EC_{50}$ values of $0.13-0.25{\mu}g/mL$, and the diatom N. annexa with $EC_{50}$ of $0.21-0.81{\mu}g/mL$.

Marine Molluscan Fauna of Jindo Island

  • Lee, Yucheol;Choe, Yeongjae;Shin, Youngheon;Kim, Taeho;Park, Jina;Park, Joong-Ki
    • Animal Systematics, Evolution and Diversity
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    • no.spc9
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    • pp.30-36
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    • 2016
  • As a part of the commemorative joint faunal survey for the 30th anniversary of the Korean Society of Systematic Zoology, the molluscan fauna of Jindo Island was investigated based on sample collection from 6 localities from the 6 to the 8 of Jul 2016. A total of 114 molluscan species from 47 families were collected and identified. Among these, 42 species from 11 families are newly reported from Jindo Island and combining the previous records with the present study totals 157 species from 57 families. Distribution of species records indicates that marine biogeography of Jindo Island represent an overlapping zone for marine organisms which dwell in the Yellow sea and the southern sea areas of Korean waters.

Types of Parasites in the Manila clam, Ruditapes philippinarum From Shi-Heung Ri on the West Cost of Jeju, Korea

  • Thao T.T. Ngo;Ko, Gwang-Jong;Park, Kwang-Sik
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • 2003.05a
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    • pp.388-388
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    • 2003
  • Parasitic organisms in the Manila clam Ruditapes philippinarium were investigated from May 2001 to April 2002 from a population of clam inhabiting intertidal zone of Shi-Heung Ri on the west coast of Jeju. Perkinsus atlanticus and Cecaria tapidis were the two main parasites that occurred firequently among the clams. Occurrence of P atlanticus varied seasonally with lowest level in late September 2001 (6.0%) and highest infection level in March 2002 (86.0%). (omitted)

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Note on the Prey Items of Marine Cladocerans (해산지각류의 먹이에 관한 보고)

  • KIM, SE-WHA;YOON, YANG-HO;ONBE, TAKASHI
    • 한국해양학회지
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    • v.28 no.1
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    • pp.69-71
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    • 1993
  • Food items of the five species of marine cladocerans were reported to be largely confined to centric diatoms. Reexamination of the prey items, however, revealed that flagellar organisms were also well fed by cladocerans. This additional finding suggests that marine cladocerans might extend their food items to weakly motile flagellates e.g., Prorocentrum micans, Protoperidinium sp. and unidentified flagellates.

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