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Uptake, Accumlation and Loss of Radioactive Cerium‐144 by Marine Planktonic Algae 1
Author(s) -
RICE T. R.,
WILLIS VIRGINIA M.
Publication year - 1959
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1959.4.3.0277
Subject(s) - cerium , algae , chemistry , particulates , salinity , environmental chemistry , nuclear chemistry , inorganic chemistry , botany , biology , ecology , organic chemistry
Following the uptake of an element by marine planktonic algae is difficult if the element occurs in both the ionic and particulate states. In this investigation the radioactive cerium (Ce 14 4 ) occurred mostly in the particulate state when added to sea water. The rate of formation of particles containing Ce 144 was influenced by dilution, temperature, salinity, added cerium, and the presence of a chelating compound. A culture of Nitzschia closterium containing dividing cells removed all the Ce 144 originally added to the medium. Different species of algae concentrated cerium from 300 to 3000 times over amounts in the medium in a period of 30 minutes. After 24 hours all 6 species tested had concentrated cerium from about 2,000 to 4,500 times. Radioactive cerium continues to be taken up for as long as three days by non‐dividing Nitzschia cells kept in the dark. The amount of cerium taken up by Nitzschia cells increased as the concentration of cerium in the medium was increased. Particulate cerium became associated with the cells at a faster rate than ionic cerium. The presence of a chelating compound in the medium resulted in a reduction in the uptake of Ce 144 by Nitzschia cells. Radioactive Nitzschia cells resuspended in nonactive medium lost about 25 per cent of their contained Ce 144 in 5 hours. More Ce 144 was lost from cells resuspended in 4 portions of nonactive medium, one after the other, than from cells remaining in the first portion of nonactive medium. A larger amount of Ce 144 was lost from cells to medium containing a chelating compound. The greatest loss of Ce 144 per unit of protoplasm in cells in nonactive medium was from “biological dilution.” This loss amounted to ½ of the contained activity of the cells at each division.