INVESTIGADORES
DIEGUEZ Maria Del Carmen
congresos y reuniones científicas
Título:
Inorganic Mercury Uptake By Plankton In Ultraoligotrophic Lakes Of Patagonia (Argentina): Does The Quality Of Dissolved Organic Carbon Matter?
Autor/es:
DIEGUEZ, M.C., RIBEIRO GUEVARA, S., QUEIMALINOS, C.P., MARVINDIPASQUALE, M., SOTO C¨¢RDENAS, C., ARRIB¨¦RE,M.A.
Lugar:
GANDST, POLONIA
Reunión:
Congreso; 15Th International Congress on Heavy Metals in the Environment; 2010
Institución organizadora:
ICHMET
Resumen:
The concentration and quality of dissolved organic carbon (DOC) have been implied as factors controlling the transformation of inorganic mercury (Hg2+) to organic Hg in Andean lakes (Patagonia, Argentina). In the current study, we further hypothesize that DOC also partially controls Hg2+ uptake into the plankton in these environments as well. This project goal was to analyse the effect of DOC quality on the uptake of Hg2+ by algae and zooplankton in waters from Lakes Moreno, Morenito, El Tr¨¦bol and Escondido, which represent a gradient in DOC quality and concentration. A series of experiments simultaneously assessed DOC quality via fluorescence spectrometry, and Hg2+ bioaccumulation in the algae Crytomonas erosa, the rotifer Brachionus calyciflorus and the calanoid copepod Boeckella antiqua. Bioaccumulation was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. the rotifer Brachionus calyciflorus and the calanoid copepod Boeckella antiqua. Bioaccumulation was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. the rotifer Brachionus calyciflorus and the calanoid copepod Boeckella antiqua. Bioaccumulation was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. the rotifer Brachionus calyciflorus and the calanoid copepod Boeckella antiqua. Bioaccumulation was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. the rotifer Brachionus calyciflorus and the calanoid copepod Boeckella antiqua. Bioaccumulation was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. the rotifer Brachionus calyciflorus and the calanoid copepod Boeckella antiqua. Bioaccumulation was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. Crytomonas erosa, the rotifer Brachionus calyciflorus and the calanoid copepod Boeckella antiqua. Bioaccumulation was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible. Brachionus calyciflorus and the calanoid copepod Boeckella antiqua. Bioaccumulation was evaluated by adding radioisotopically enriched 197Hg2+ into flasks containing the various lake waters (pre-filtered through 0.2 ¦Ìm) with the organisms. After incubating for 24 hours in darkness, 197Hg specific activity was measured in the organisms recovered from the water. The uptake of Hg2+ by pelagic organisms was found to be highly variable as a function of the natural DOC gradient. The use of killed controls also suggested that the passive Hg2+ uptake appears as the dominant mechanism in the accumulation of Hg2+ from the environment by live algae. In herbivorous zooplankton, the highest uptake of Hg2+ was found to be dietary while the passive uptake of dissolved Hg2+ was almost negligible.