A diverse array of interactions in forest ecosystems are mediated by biological signalling chemicals. These chemicals include information-laden volatile odours and distasteful toxins that constitute defences. Recent research has found that air pollution has complicated effects on chemically-mediated interactions. Importantly, it was found that secondary organic aerosols derived from oxidation of volatile chemicals, can convey nuanced information to plants. These observations suggest that information encoded in chemical cues may have time and distance dimensions, which have not before been documented. How these interactions function in forest ecosystems is completely unknown. In this project, we will work at all scales at which biochemicals function above and belowground, from the defensive polyphenols in plants, via volatile odours, to their atmospheric reaction products. Our vision is to open a new branch of chemical ecology that incorporates biosphere-atmosphere feedback processes.

2026

2028