Journal of the Marine Biological Association of India

Uptake and loss of radioactive Zinc-65 by two species of marine chlorophycean flagellates.

Volume 21 Issue 1&2

K. V. K. Nair and C. D. Mulay

Abstract

Uptake and loss of 65Zn was followed in laboratory cultures of two species of marine chlorophycean flagellates, Dunaliella primolecta and Chlamydamonas sp. In both the species the uptake of activity in the cells closely followed the population growth pattern. Chlamydomonas sp. removed almost all the added 65Zn within a period of about 20 days, whereas 40% of the initial activity remained in the medium even after 28 days in the case of Dunaliella primolecta.

Radioactive cells lost only less than 2% of the activity when washed four times in nonactive medium. Chlamydomonas sp. cells resuspended in nonactive medium lost about 28 % of the activity to the medium in 14 days, whereas Dunaliella sp. lost very little activity to the medium during the same period. With the addition of EDTA to the medium, Chlamydomonas sp. lost 50 % of the activity within five hours and all the activity within 14 days. Dunaliella sp. lost 6.6% within five hours and it took 14 days to lose 50% of the activity.

At apparent equilibrium, Chlamydomonas sp. showed a concentration factor of 14,400 whereas Dunaliella primolecta showed a concentration factor of only 8,000. If the assimilated fraction of 8 B Zn is only taken for the calculation of concentration factor the figures are not significantly different for both the species.

Date : 31-12-1979