FORD, D.K.; Ohio University: Sublethal physiological effects of multiple stressors on energy allocation patterns of Malaclemys terrapin

Stress is an environmental condition or external constraint that restricts the rate of resource acquisition and energy allocation that may ultimately reduce survivorship or fecundity. An organism incurs an energetic cost, such as an increase in metabolic rate, when exposed to an environmental stressor. This increase in metabolic rate commonly causes a decrease in growth or reallocation of energy from storage or reproduction. Due to its estuarine natural history, diamondback terrapins are exposed to a wide range of salinities and multiple chemical stressors. Pilot study results suggested that hatchling terrapins exposed to even small amounts of PCBs had significantly reduced growth rates. In order to increase biological realism, I conducted a second study to determine how both the anthropogenic stressor used in the pilot study (PCB 126) and a salinity stress affect resource allocation. Animals held at higher salinities had a higher standard metabolic rate than those that were held in 0ppt saltwater or at their acclimation salinity. Furthermore, individuals held at high salinities that were also exposed to PCBs exhibited an even greater standard metabolic rate and reduced growth. These data suggest that sublethal levels of stress can have far-reaching consequences though their effects on resource allocation and these effects may be amplified by additional stressors.