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[en] Variation of environmental parameters and copepods population were studied in the Oum Er Rbia estuary (Atlantic - Moroccan coast) according to the seasons, ( August 1995 to August 1997), tides and reservoir release events. Environemental variability influences copepods diversity and abundance. Salinity (5 to 20 g l-1) appears as the main controlling factor. Among the 27 copepod species recorded, only three marine species (Oithona helgolandica, Euterpina acutifrons, Acartia clausi) and one freshwater species (Acanthocyclops robustus) are able to maintain significant populations due to their large degree of tolerance to salinity changes. (author)

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[en] The radioactivities of beta rays of the caught shrimps at the coastal area in Inchon are investigated. The samples of the shrimps were taken randomly on the six places for three months period for two years. The overall average radioactivity is 21.9x10^-2 pci/gr. Especially the radioactivity of one of the places is 29.6x10^-2 pci/gr and this is the most highest value, However, this value is lower than the values of fishes and sea weeds of the places. Therefore, the radioactivity of caught shrimps in this area are almost he level of the natural radioactivities and the results of the study seem not contaminated of the fallout. (Author)

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[en] To date, the phenomenon of radiation-induced transgenerational inheritance has been extensively analyzed by studying the progeny of irradiated Daphnia. According to the results of our studies, compromised survival of the directly irradiated Daphnia magna was observed following exposure to a wide range of doses of acute exposure to γ-rays. The survival of D. magna exposed to 10 mGy of γ-rays does not significantly differ from that in controls, whereas it is significantly compromised at 0.1, 1 and 10 Gy. The life expectancy of irradiated animals was 20-30% lower than in the control. According to our data, parental exposure to 1 and 10 Gy significantly compromised the first viability. The magnitude of transgenerational effects was close to the direct effects on the parental generation. On the other hand, the survival of second-generation progeny of irradiated parents does not significantly differ from that in controls. We have shown significantly elevated cytotoxicity in D. magna exposed to 0.1, 1 and 10 Gy. We found that the toxic effect also manifested in the F1 progeny of irradiated D. magna. We also found that in D. magna the level of free radical is significantly elevated following exposure. It would therefore appear that the abovementioned cytotoxic effects may explain the compromised viability of irradiated D. magna. According to our results, parental acute exposure of D. magna at doses of 0.100-10 Gy significantly compromise the main components of total fertility – the number and size of broods. The effect was maintained in the F1 generation and almost leveled in F2 and remains compromised following parental high-dose exposure to 10 Gy. The decrease in the number of broods in F0 is attributed to the cytotoxic effect of radiation on the germ cells. Given that we analyzed parthenogenetic strain of D. magna, we irradiated of primordial diploid eggs, the results of abovementioned studies provide a plausible explanation for the compromised fertility of irradiated exposed D. magna. The described transgenerational effects can only be explained by epigenetic mechanisms. The main argument for this is the very high incidence of mortality among the progeny of irradiated parents, which cannot be attributable to a Mendelian segregation of radiation-induced mutations.

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