WA5 Making Ecotoxicology Studies Relevant
Room 17A/B, Level 4
8:00 AM - 12:00 PM, Wednesday, 12 November 2003
Chair: Adams, Marshall ,
(365) Adressing the "So What"-question: cellular energy budgets as an extrapolation currency.
Smolders, R.1, De Coen, W.1, Blust, R.1, 1 University of Antwerp, Antwerp, Belgium
ABSTRACT- Toxic exposure of organisms interferes with organismal integrity at the molecular and cellular level of biological organization and ultimately gives rise to effects at the organismal level. This will eventually result in reduced ecologically relevant characteristics such as survival, growth and reproduction. Since organisms exposed to suboptimal conditions face an a priori cost of combating stress in terms of metabolic resources, the energy available for maintenance, growth and reproduction may provide a sensitive measure of stress in organisms. In this work, we will address the use of cellular energy budgets as an extrapolation currency to link different levels of biological organization, and we will illustrate this by providing two case studies. The first case study describes the effect of individual chemicals with different modes of action on the cellular energy allocation (CEA) of Daphnia magna, where the effect of short-term (96h) exposure on CEA was linked to population level parameters (obtained from 21 day life table experiments) such as the intrinsic rate of natural increase and the mean total offspring per female. A second case study describes a chronic toxicity test with zebrafish (Danio rerio), where fish were exposed to different effluent concentrations for 28 days under flow through conditions. Effects of effluent exposure were determined on a cellular (glycogen-, lipid- and protein-budgets), physiological (respiration during swimming), organismal (condition, growth), and reproductive (spawning and hatching) level of biological organization within the same population. Both case-studies illustrate that measurements at different relevant levels of biological organization provide a rational basis to increase the ecological relevance in toxicity testing. Also, cellular energy budgets are a sensitive and fast indicator of pollutant exposure and allow quantitative extrapolation of effects from cellular to higher levels of biological organization.
Key words: ecological relevance, Energy budgets, biological organization