• Title/Summary/Keyword: Bivalves

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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.

A Study on Polybrominated Diphenyl Ethers and Organochlorine Compounds Residues Persistent in Korean Coastal Bivalves (한국 연안 이매패류에 잔류하는 PBDEs 및 OCs에 관한 연구)

  • Min, Byung-Yoon
    • Journal of Environmental Health Sciences
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    • v.36 no.2
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    • pp.118-127
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    • 2010
  • Bivalve samples from 30 locations Korean coastal waters were analyzed to characterize the contamination with and distribution of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). The congeners of PBDE in 30 bivalve samples were analyzed by high resolution gas chromatography with a high resolution mass detector. The levels of PBDEs in bivalve samples ranged from 0.092 to 13.5 ng/g wet weight. These values for PBDEs concentrations in bivalves from Korea were higher than or comparable to available values for bivalves from other countries. In the congener profiles, BDE-47 (mean contribution=42.2%) was predominant, followed by BDE-99 (23.1%), BDE-100 (11.9%) and BDE-154 (3.5%). Among the OCs analyzed, $\Sigma$PCBs and $\Sigma$DDTs levels were highest, followed by $\Sigma$HCHs, $\Sigma$CHLs and HCB. The wet weight based $\Sigma$PCBs and $\Sigma$DDTs ranged from 0.28 ng/g to 19.4 ng/g, and from 0.19 ng/g to 4.86 ng/g, respectively. The $\Sigma$PCBs and $\Sigma$DDT slevels in bivalves along the entire Korean coast were lower than those of the USA, and below the Food and Drug Administration (USA. FDA) limits for fish and shell fish. However, the human health criteria and wild life criteria of the USA. Environmental Protection Agency (USA. EPA) were exceeded for DDE and $\Sigma$HCHs at most of the sampling points.

Comparison of hemocytic carbonic anhydrase activity of bivalves

  • Cho, Sang-Man;Jeong, Woo-Geon;Choi, Young-Joon
    • The Korean Journal of Malacology
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    • v.32 no.1
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    • pp.63-65
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    • 2016
  • Carbonic anhydrase (CA), which is involved in shell formation processes in bivalves, is one of the major biocatalysts for carbon capture and storage. In this study we investigated CA activity in the total hemocytic proteins of five bivalves. The highest CA activity was observed in Scapharca broughtonii, which had more than twice the activity found in Crassostrea gigas. No CA activity was observed among the total hemocytic proteins of Pinctada fucata and Saxidomus purpuratus. The results suggest that marine invertebrates may provide a better source of CA, as an alternative to mammalian sources.

Mollusk Species Associated with the Scleractinian Coral Alveopora japonica Eguchi, 1968 Forming a Coral Carpet in Northwestern Jeju Island

  • Ronald G., Noseworthy;Hyun-Ki, Hong;Se-Jong, Ju;Hyun-Sung, Yang;Kwang-Sik, Choi
    • Ocean and Polar Research
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    • v.44 no.4
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    • pp.331-338
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    • 2022
  • The high latitude scleractinian coral Alveopora japonica Eguchi, 1965 occurs in high density in the shallow rocky subtidal in Jeju Island, forming coral carpets. Despite its ecological role providing a unique habitat for other benthic organisms, the benthic fauna associated with the A. japonica coral carpet is poorly known. To identify fauna associated with the coral carpet, we explored three sites dominated by A. japonica and one control site on northwestern Jeju Island in May 2013. Using SCUBA, we collected A. japonica and the epibenthic mega-fauna associated with the colonies in 1×1 m2 and identified them to the species level. At a depth of 10 to 15 m, A. japonica colonies heavily covered the seafloor, forming a layer called a coral carpet, with a density of 94 (Keumneung-ri), 133 (Biyangdo), and 155 (Gwidok-ri) colonies/m2. Thirty-four molluscan species were identified from the four sites, including 20 bivalves and 14 gastropods. The coral carpets were enriched with sessile bivalves compared to the control site, as we identified twenty bivalve and eight gastropod species from the coral carpets. Most bivalve species associated with the coral carpets had tropical-subtropical affinities, while gastropods were mainly subtropical and subtropical-low boreal species. Leiosolenus lischkei M. Huber, 2010, in the family Mytilidae and Barbatia steamsi (Pilsbry, 1895), in the family Arcidae, were the two most abundant bivalve species in the coral carpet, L. lischkei being a borer, and B. stearnsi a nestler. The tropical to subtropical Pacific star shell Astralium haematragum (Menke, 1829)was the most abundant gastropod at the study sites. The bivalves and gastropods associated with the coral carpet were small-sized juveniles or sub-adults, suggesting that the coral carpet provides a micro-habitat for the bivalves and gastropods.

Feeding Ecology of Sillago japonica in an Eelgrass (Zostera marina) Bed

  • Kwak Seok Nam;Baeck Gun Wook;Huh Sung-Hoi
    • Fisheries and Aquatic Sciences
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    • v.7 no.2
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    • pp.84-89
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    • 2004
  • Feeding habits of Sillago japonica collected from in an eelgrass (Zostera marina) bed in Jindong Bay, Korea were studied. S. japonica was a carnivore which consumed mainly gammarid amphipods, polychaetes, bivalves, caridean shrimps and crabs. Its diets also included a small amount of fishes, copepods and caprellid amphipods. The diet of S. japonica underwent significant size-related changes; small individuals (<5cm SL) fed mainly on gammarid amphipods and crab larvae, while proportion of polychaetes and bivalves increased with increasing fish size and gammarid amphipods were also important prey for medium size individuals (5.1-9.9cm SL). The large individuals (>10cm SL) ate polychaetes, caridean shrimps and crabs. The dietary breadth of S. japonica were varied with size. The diet of S. japonica also underwent seasonal changes that could be related to differences in prey availability; gammarid amphipods were mainly consumed in spring and polychaetes in summer.