W9 AM Biomonitoring
Wednesday, 16 November 2005: 8:00 AM - 11:40 AM in 339-340

(NGU-1117-821742) Testate amoebae as indicators of atmospheric metal pollution: a combined approach of field/laboratory experiments.

Nguyen-Viet, Hung¹, Bernard, Nadine¹, Mitchell, Edward², Badot, Pierre-Marie¹, Gilbert, Daniel¹, ¹ Laboratoire de Biologie Environnementale, USC INRA, EA 3184, Université de Franche-Comté, Besançon, France² Laboratoire des Systèmes Ecologiques – LECOS, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland

ABSTRACT- We studied the effect of heavy metals on testate amoebae by a combined approach of field and laboratory experiments to assess their potential use as bioindicators of atmospheric pollution by heavy metals. In the field experiment we studied the relationships between testate amoebae and heavy metal concentrations in mosses sampled at 29 sites in Hanoi (city, 19 sites; surroundings, 10 sites). The concentrations of heavy metals (Lead, Cadmium, Zinc, Nickel and Copper) in the moss were higher and the testate amoebae species richness and abundance were lower in the city than in the surroundings. Species richness was positively correlated to abundance and both were negatively correlated to lead concentration. The abundance of several species was negatively correlated with lead, cadmium, zinc, nickel but at the community level, lead emerged as the only significant variable in a redundancy analysis. In the second experiment we studied the effect of lead on testate amoebae communities living in mosses under controlled conditions. Mosses were grown in the laboratory with 0 (C: control), 625 (treatment E625) and 2500 (E2500) microgram.L-1 of Pb2+ diluted in a standard nutrient solution and were sampled after 0 (T0), 6 (T6), 12 (T12) and 20 (T20) weeks of exposure. The total abundance of active amoebae was positively correlated to the number of species in E2500 and E625 but not in C. Species richness was significantly lower at T16 for E2500 and T20 for both E625 and E2500 as compared to the control. At T20, testate amoebae abundance was significantly higher in C than in E2500. Species richness and total abundance were negatively correlated with lead concentrations. Species-specific responses to lead pollution were also observed. Our results showed that testate amoebae are sensitive to, and could therefore potentially be good bioindicators of, heavy metal pollution, especially lead.

Key words: Heavy metals, Testate amoebae, Mosses, Bioindication