Meeting Abstract
In their natural environment, organisms typically encounter natural stressors throughout their lifetime. Although these organisms are well-adapted to succeed in their habitat, “non-optimal” conditions can require costly physiological adjustments. These physiological responses are still poorly understood. Harmful algal blooms are a common stressor for herbivorous copepods that ingest toxic phytoplankton such as the saxitoxin-producing dinoflagellate, Alexandrium fundyense.The effect of this toxic alga on the physiology of the calanoid copepod, Calanus finmarchicus was investigated using transcriptomics. Gene expression in C. finmarchicus was determined after 2 and 5 days feeding on A. fundyense and compared with females on a control diet. A significant time and dose response was observed in C. finmarchicus with over 1,000 genes being identified as differentially expressed (DE) in response to A. fundyense . At 2 days, the response was similar to the cellular stress response with genes involved in chaperone and redox reactions, intracellular signaling, protein degradation and energy metabolism (lipid and carbohydrate). At 5 days, the transcriptional response reflected a physiological adjustment towards the new environmental conditions. Transcripts encoding proteins involved in energy metabolism were significantly regulated, suggesting a difference in the energy balance between the control and experimental females. Surprisingly, detoxification was not a major component of the copepod response to the dinoflagellate. Overall, the results suggest that the copepod is able to consume the toxic dinoflagellate with little effect on survival, but its energy budget is affected and fewer resources are available for growth.
