W7 AM Acclimation / Adaptation of Animals to Metals: Resistance, Tolerance, and Cost
Wednesday, 16 November 2005: 8:00 AM - 11:40 AM in 327-329

(KLE-1117-564015) Adaptation to metals in aquatic organisms: lessons learned from Foundry Cove and beyond.

Klerks, P¹, Xie, L¹, Levinton, J², ¹ University of Louisiana, Lafayette, Louisiana, USA² State University of New York, Stony Brook, New York, USA

ABSTRACT- Individuals of a population may differ genetically with respect to their sensitivity to metal toxicity. The selective pressure exerted by long-term exposure to toxic metal levels may thus result in the evolution of resistance in populations inhabiting metal-contaminated sites. The ultimate fate of such adapted populations can depend on fitness costs associated with the adaptation, while implications for the ecosystem may depend on the resistance mechanisms. These various issues are important when assessing metal risks and when setting environmental quality criteria. This presentation will address the occurrence of adaptation, associated fitness costs, and resistance mechanisms, focusing mainly on the oligochaete Limnodrilus hoffmeisteri inhabiting Cd-contaminated Foundry Cove and on a laboratory selection experiment with the least killifish Heterandria formosa selected during six generations for an increased resistance to cadmium. Results show that resistance can evolve very rapidly (though some populations fail to adapt), and that resistance may also be lost rapidly once a population is no longer exposed to the pollution. Various fitness costs were identified in the laboratory-selected population, but were less evident in the natural population in Foundry Cove. Metal accumulation and detoxification differed between adapted and control populations, indicating that the presence of metal-adapted populations affects the potential for trophic transfer of a metal.

Key words: metal, adaptation, resistance, fitness cost