Chemosensory systems are widespread in the Animal Kingdom. However, our understanding of such systems in the marine environment is minimal. Anthropogenic input affects these systems through sub-lethal toxicity to the sensory organs and/or by altering the bioavailability of odorants. However, another effect is possible; chemicals of human origin entering coastal waters via waste-water treatment plants may mimic natural semiochemicals, thereby acting as 'olfactory disruptors'.

The aim of this project is to establish whether such olfactory disruption may be occurring in the Ria Formosa. We will isolate and identify odorants of human origin in wastewater using sentinel species living in the Ria - fish, crustaceans and bivalve molluscs - and compare them to natural semiochemicals.

We will sample wastewaters from treatment plants that discharge into the Ria Formosa. We will use electrophysiological bioassays to lead fractionation, isolation and chemical characterization of odorants. In parallel, we will use the same experimental approach with water conditioned by the study species to identify natural semiochemicals.

The proposed project will make significant advances in the characterization of natural semiochemicals involved in the food-chain of a natural marine ecosystem. The ultimate aim is to explore and evaluate the potential of Contaminants of Emerging Concern (CECs) in the disruption of olfaction, a physiological process of crucial ecological importance in marine environments, in an innovative way.