Biological clocks in pelagic systems

forthcoming

Coordinated vertical migrations of animals in open waters (pelagic zone) are among the largest biomass movements on Earth. They structure marine ecosystem and are thereby essential to humans (e.g. fisheries, carbon-cycle). Yet, the mechanisms of these migrations are hardly understood, especially the impact of endogenous clocks vs. direct responses to environmental cycles. Endogenous clocks are central to various organismal rhythms. Importantly, they maintain organismal rhythmicity even under constant environmental conditions, clearly distinguishing clock-driven processes from those that are directly environmentally-controlled. Pelagic vertical migration behavior, environment and clocks strongly feed back onto each other, but molecular mechanistic functioning under these conditions is at present not understood at all, largely due to the lack of a pelagic lab animal model. BICLOPS will determine the role of endogenous clocks and different environmental cues in shaping pelagic vertical migrations, using the copepod Calanus finmarchicus – a Northern Atlantic ecological key species – as a lab model system. I will combine my expertise with this species and with ecological and functional molecular approaches to address four objectives: – determine how light affects the circadian clock and define neural clock centers and light receptors. – determine circadian clock functional interactions and effects of temperature/oxygen cycles. – identify external/internal regulators of copepod seasonal diapause. – determine how individual clock components affect diel and seasonal rhythmicity by functional clock interference. By determining clock functioning in a representative pelagic key species under environmental cycles shaped by the migrations themselves, BICLOPS will transform our knowledge of pelagic rhythm mechanisms. Understanding the processes that structure pelagic ecosystems is essential to predict their responses to climate change and implement measures to preserve them.