• Ocean and Polar Research
• /
• v.25 no.2
• /
• pp.147-154
• /
• 2003

To develop fast and sensitive biomarkers for metal exposures in Antarctic marine organisms we examined histological alterations of an Antarctic sentinel bivalve species Laternula elliptica following a short-term exposure to a sublethal-level of Cd. Distinct histological alterations of tissues and cells of the gills, kidneys, and digestive glands were observed after 8-to 16-hours of exposure to Cd while an increase of Cd concentrations in tissues was not detectable. Most alterations were highly localized in the epithelium of the three tissues; epithelia were found to be detached from the remaining tissue parts. In addition ultra-structural changes such as cytosolic vacuolization, dilation of nucleus and rER membranes were detected in all three tissues, which suggested that the clams are subject to sublethal stresses. Thus, histological and ultrastructural changes on localized tissue parts were rapid and sensitive, suggesting that they may serve biomarkers for Cd exposures. Linkages between the shown ulrastructural changes and higher biological organization level responses are to be established by longer-term exposure experiments.

• The Korean Journal of Malacology
• /
• v.26 no.3
• /
• pp.227-234
• /
• 2010

A comparative analysis of size and age structures of coastal subfossil shell assemblages of the shortnecked clam Ruditapes philippinarum from open and protected bays of Cheju Island (Korea) was carried out. On the whole, taking into account the damage of small fragile shells, size and age structures of the shell assemblages corresponded to the classical curve of bivalve population distribution when its mortality diminishes with age increase up to a certain threshold. It was found that shell samples from open bays of the western, southern and eastern coasts included shells of smaller and younger individuals (L ${\leq}$ 40 mm, ${\leq}$ 4 years) than samples from the eastern protected bay (L ${\leq}$ 54.5 mm, ${\leq}$ 6 years). Evidently, strong wave activity was the reason for a short life-span of the clams from the open areas. Growth was investigated retrospectively by annual growth rings on the shells. Growth rates of the clams from the various coasts of Cheju Island differed. However, growth rates of the clams from different biotopes at the same (eastern) side of the Island were similar. Shell height/length and width/length ratios statistically significantly increased with the clam age increase. Most likely, the reason for such shell shape alteration is that more conglobated individuals more survive being more energy-optimal than oblong specimens.

• Journal of the Korean earth science society
• /
• v.29 no.1
• /
• pp.13-28
• /
• 2008

About 450 specimens of Lockeia were discovered from the lacustrine siltstone of the Early Cretaceous Jinju Formation of Jin Island, southern coast of Korea. They are very elongated, seed-shaped Lockeia characterized by a large size, mostly 60-70 mm long and 15-20 mm wide. They are characteristically sharp longitudinal furrow bounded by steeply inclined both margins, elevated marginal rims and sharp pointed both longitudinal furrow ends. This trace fossil is herein described as Lockeia gigantus ichnosp. nov. Plicatounio, a freshwater bivalve which does not occur occurs occasionally within Lockeia gigantus is regarded as the most-likely producer of this resting trace fossil. This new trace fossil represents the largest Lockeia ever known and the first record of Lockeia from the Cretaceous non-marine deposits in the world. This fossil also represents an unusual example of resting trace fossil (Lockeia) associated with a possible producer (bivalve Plicatounio) lived in community in the shallow lacustrine environment.

• Journal of Food Hygiene and Safety
• /
• v.36 no.6
• /
• pp.455-473
• /
• 2021

In order to aid the researchers who analyze the biotoxins in marine molluscs, this paper introduces the official names and ecological characteristics of the domestically produced or distributed bivalve and gastropods that can be contaminated with marine biotoxins. Also, the paper intends to inform the location and scientific name of each organ of the representative group of species through anatomical maps. In the future, it is necessary to standardize and normalize the names of the species and the research institutions in food codes, scholarly papers and reports on the marine biotoxin analysis.

• The Korean Journal of Malacology
• /
• v.32 no.1
• /
• pp.63-65
• /
• 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.

• The Korean Journal of Malacology
• /
• v.31 no.1
• /
• pp.35-41
• /
• 2015

In order to investigate the live food value of microalgae for efficacious rearing of larvae and spats of bivalve, we studied growth rates of four microalgal species (Isochrysis galbana, Pavlova lutheri, Chaetoceros simplex, Tetraselmis tetrathele) cultured in different environmental conditions. These include changes in temperatures (20, 25, 30 and $35^{\circ}C$), salinities (20, 25, 30 and 33 psu) and light intensities (60, 100 and $140{\mu}mol\;m^{-2}s^{-1}$). The growth rate of I. galbana was faster at $25^{\circ}C$ than that of $20^{\circ}C$. At $25^{\circ}C$ the highest growth rate of I. galbana was observed at 33 psu (0.413) and the lowest at 20 psu (0.368) in 10 days of culture (P < 0.05). The growth rate of I. galbana was lower at 25 psu (0.383) than that of 30 psu and higher than that of 20 psu (P < 0.05). Similar temperature and salinity-dependent changes were also found in P. lutheri and T. tetrathele. C. simplex showed faster growth rate at $30^{\circ}C$ than that of $25^{\circ}C$. The highest growth rate of C. simplex was observed at 33 psu (0.428) and the lowest at 20 psu (0.389) in 10 days of culture (P < 0.05). Upon exposure to the light with different intensities, all four microalgal species showed a significantly faster growth rate at $140{\mu}mol\;m^{-2}s^{-1}$ than at $100{\mu}mol\;m^{-2}s^{-1}$ (P < 0.05).

• Environmental Engineering Research
• /
• v.25 no.1
• /
• pp.43-51
• /
• 2020

The present study was designed to characterize the bioaccumulation of organochlorine pesticides (OCPs) in marine organisms (zooplankton, oyster, crab, and goby) on different trophic level. In the present study, sedentary bivalve (oyster) showed strong correlations in OCPs levels with surface sediment in the study area. This indicates the two compartments can be used as alternative for pollution monitoring of OCPs even in narrow scale in space. Bioaccumulation and trophic transfer of OCPs was strongly associated with their hydrophobicity (i.e., K_OW). HCHs with log K_OW < 5 did not show any enrichment through food-chain. However, log BAF values of OCPs with log K_OW > 5 positioned over the 1:1 lines of log BAF and log K_OW of the top predator, indicating the greater fugacities in the higher trophic level and thus the occurrence of biomagnification via ingestion. Based on trophic transfer factors (TTF), more hydrophobic OCPs with log K_OW > 5 were enriched by several to several ten times in the highest trophic level relative to the lowest trophic level. This finding can be used in the establishment of marine environmental water quality criteria by considering biomagnification factors (TTF in this study) of OCPs.

• Fisheries and Aquatic Sciences
• /
• v.7 no.3
• /
• pp.141-147
• /
• 2004

Sixteen polycyclic aromatic hydrocarbons (PAHs) were analyzed in seventy marine organisms (40 species) from the Korean coast. PAHs were present in all the organisms. The level of total PAHs in the organisms varied from 0.45 to 224 ng/g dry weight and the carcinogenic PAHs varied from 0.05 to 49.8 ng/g dry weight. The PAHs residues according to the marine organisms showed a highest content in bivalve species, and followed by crustaceans, cephalopods, fish and gastropods. Human dietary intake of total PAHs through marine organism in Korea was estimated to be 4.12 ng/kg body weight/day and 0.67 ng/kg body weight/day for carcinogenic PAHs. The relative contributions of individual species to the total dietary intake of PAHs were in the order of bivalves $(53.4{\%})$, fish $(21.9{\%})$, crustaceans $(15.3{\%})$, cephalopods $(8.8{\%})$ and gastropods $(0.6{\%})$. Daily dietary intake of $PAH_{TEQ}$ expressed as a TEQ value was estimated to be 0.13 pg TEQ/kg body weight/day, which did not exceed a tolerable daily intake (TDI) proposed by the KFDA and the WHO as well as the UK toxicity committee. Lifetime cancer risk due to ingestion of marine species by the Korean adult was evaluated using the equation estimating exposure of food ingestion. Although approximately $23{\%}$ of cumulative frequency of the sampled marine species exceeded the cancer risk guideline, lifetime cancer risk associated with marine organism consumption was negligible. Results indicate that dietary intake of PAHs through the consumption of the Korean marine organisms seems to be safe for human ingestion with negligible cancer risk.

• Korean Journal of Ichthyology
• /
• v.27 no.1
• /
• pp.33-38
• /
• 2015

The diet composition of Leiognathus nuchalis were studied using 350 specimens collected from October 2010 to September 2011 in the coastal waters of Gadeok-do, Korea. L. nuchalis was carnivorous feeder that consumed mainly copepods, crab larvae, and shrimp larvae. Its diet also included small quantities of polychaetes, amphipods, euphausiids, bivalve larvae, and gastropod larvae. The size of L. nuchalis ranged from 3.0 to 9.8 cm in body length (BL). L. nuchalis underwent an ontogenetic dietary shift. 3~5 cm size individuals fed mainly on copepods. 5~7 cm size individuals fed mainly crab larvae and shrimp larvae. 8~10 cm size individuals fed mainly polychaetes. The size increases, the weight of food organisms are constantly increased.

• The Korean Journal of Malacology
• /
• v.32 no.3
• /
• pp.203-209
• /
• 2016

Growth and survival of the hard shelled mussel spat were investigated to confirm the possibe spat culture in seawater pond from September 2014 to April 2015. Also, we measured simultaneously environmental factors including water temperature, salinity, dissolved oxygen, pH, DIN, DIP, chlorophyll a, and abundance and dominant species of phytoplankton in seawater pond every month. Ranges of water temperature and salinity were $4.0-23.4^{\circ}C$ and 18.8-25.2 psu, respectively, which were rather lower than the reported optimal level. Monthly measured survival rates in all the spat cages were over 90%. Concentration of chlorophyll-a and abundance of phytoplankton were very high, and dominant species phytoplankton were cryptomonads and nanoflagellates. These dominant species were considered to be good food organisms for the bivalve spat. The experimental cage stocked 100 individuals per basket ($2,700ind.\;m^{-2}$) hanging in bottom of seawater pond revealed the highest growth in shell height ($7.63{\pm}4.65mm$), but all experimental cages stocked below 200 individuals per basket ($5,400ind.\;m^{-2}$) did not show statistically significant difference. We may expect that seawater pond would be one of the best culture ground for bivalve spats when appropriate measures are available.