Chemical tracers of bioenergetics and energy acquisition in aquatic ectotherms

点击翻译按钮获取中文摘要

All animals must acquire energy through their feeding activities but obtain food resources from their environment in different ways depending on 1) the species 2) feeding ecology differences among populations living in different environments and 3) individual variation in feeding behavior within a given environment. Bioenergetics and bioenergetic models provide a method to establish the energy balance (kilojoules of food consumed per day relative to total daily energy needs or field metabolic rate) in animals and when coupled with biomass/production estimates allow an assessment of the trophic impacts, or the ecological footprint, of a given population on its environment. This type of information is needed to validate theoretical models of food web structure and to test the relationship between species diversity and ecosystem stability. Developing methods to measure animal bioenergetics in natural environments also has applications to establish the implications of fish stocking programs, invading species or fluctuations in key prey items in an ecosystem. Characterizing bioenergetics parameters (e.g. growth and food consumption) also allows assessment of the relative health of a population. Many stressors (e.g. toxic chemicals, nutrient enrichment, habitat loss and global warming) manifest themselves as bioenergetic effects and can provide an early warning of impacts of stressors on the population. This proposal will evaluate the use of persistent organic pollutants (POPs) as tracers of energy acquisition and feeding rates in free living aquatic amphibians and fish. Legacy pollutants such as the long-banned PCBs are globally distributed, exhibit reduced toxicity on account of decreases in environmental concentrations, and provide good tracers of ecological structure and bioenergetics. The described methods will use laboratory studies, pond-studies (mesocosms) and natural lakes and several indicator species including: leopard frogs, green frogs, bullfrogs, sunfish and rainbow trout to establish the method of POPs as bioenergetic tracers and evaluate the potential application of this technique to ecosystem management and ecosystem health assessment practices.