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524726 
Journal Article 
Contrasting transfer of polonium-210 and lead-210 across three trophic levels in marine plankton 
Stewart, GM; Fowler, SW; Teyssie, JL; Cotret, O; Cochran, JK; Fisher, NS 
2005 
1 
Marine Ecology Progress Series
ISSN: 0171-8630
EISSN: 1616-1599 
INTER-RESEARCH 
OLDENDORF LUHE 
290 
27-33 
English 
WOS:000229079800003 
The naturally occurring radionuclides Po-210 and Pb-210 can be used as geochemical tracers in marine systems, but their interactions with biota in surface waters need to be understood before oceanographic data can be interpreted unambiguously. We compared the food chain dynamics of these radionuclides in plankton assemblages by measuring the uptake and trophic transfer of Po-210 and Pb-210 from phytoplankton to brine shrimp Artemia sp. to euphausiids Meganyctiphanes norvegica under controlled laboratory conditions. The ratio of Po-210:Pb-210 within organisms increased 5- to 12-fold with each trophic level (phytoplankton to grazer to carnivore), reflecting a preferential bioaccumulation of Po-210 over Pb-210. M norvegica assimilated 44 % of the polonium ingested but only 3.5% of the Pb-210 ingested. Because Pb-210 was unassimilated, the ratio of Po-210:Pb-210 was 1 to 2 orders of magnitude smaller in zooplankton fecal pellets than in the animals producing them. These results suggest that in surface waters Po-210 has the potential to build up in food chains and be biologically recycled, whereas Pb-210 would not build up in marine food chains and would display shorter residence times. Since euphausiids comprise an important link between small plankton and larger predatory animals in many marine ecosystems, they may serve as an important conduit of Po-210 to those predators consumed as seafood by humans. 
polonium; lead; trophic transfer; plankton; bioaccumulation; residence; time; Artemia; krill; krill meganyctiphanes-norvegica; mussel mytilus-edulis; northern krill; ligurian sea; trace-metals; mediterranean-sea; euphausia-superba; antarctic krill; food; accumulation