Thallium in marine plankton

Abstract

Concentrations of thallium in phytoplankton (0.02 to 0.8 μg g^(−1)), zooplankton (0.03 to 0.5 μg g^(−1)) and ichthyoplankton (0.1 μg g^(−1)) from the central Pacific were comparable (x¯=0.2μg g^(−1)) , as were the atomic ratios of thallium to calcium (∼3x10^(−6)) and to potassium (∼1x10^(−6)) in those organisms. These relatively constant ratios, plus the biounlimited ocean profile of thallium, indicate that it is rapidly cycled through plankton in the same manner as potassium, its principal biogeochemical analogue. The higher atomic ratios of thallium to potassium in pelagic clays (6x10^(−6)) and ferromanganese nodules (4x10^(−3)) suggest that both biological transport processes and abiotic transport processes influence this trace element's oceanic cycle.

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