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Accumulation of Th, Pb, U, and Ra in marine phytoplankton and its geochemical significance 1
Author(s) -
Fisher N. S.,
Teyssié J.L.,
Krishnaswami S.,
Baskaran M.
Publication year - 1987
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.1987.32.1.0131
Subject(s) - picoplankton , phytoplankton , plankton , bioaccumulation , environmental chemistry , exopolymer , nuclide , oceanography , artemia salina , volume (thermodynamics) , biology , chemistry , geology , ecology , nutrient , physics , paleontology , organic chemistry , toxicity , quantum mechanics , bacteria
The bioaccumulation of U, Th, Ra, and Pb in four diverse nanoplanktonic algal species and a picoplanktonic blue‐green alga was determined with radiotracers. Among the nanoplankton, differences of 1–2 orders of magnitude in volume/volume concentration factors (VCFs) were observed for a given nuclide, but larger differences were observed among the four nuclides, with VCF values of Th > Pb > Ra ≃ U. The picoplankton cells, with greater surface: volume ratios, had significantly higher VCF values. The mean VCF values in the nanoplankton of Th and Pb were 1.5 × 10 5 and 3.6 × 10 4 in the light and 2.8 × 10 5 and 7.3 × 10 4 in the dark. The VCFs of Th and Pb in the picoplankton were both about 2 × 10 6 , irrespective of light. Retention half‐times of 228 Th and 210 Pb in fecal pellets of Artemia salina , fed radiolabeled diatoms, were 20–50 d, but >120 d for 228 Th at 4°C. The results suggest that sinking plankton and their debris could account for most of the natural series radionuclides sedimenting out of oceanic surface waters.