Emergence of Collective Behaviour in Motile Marine Organisms

Collective dynamics of motile entities is one of the primary areas within the field of 'active matter', where large-scale coordination emerges from energy input at the smallest scales. The twin goals of this broad area of research, still open, involve understanding the physical mechanisms behind the emergence of coordinated motion, and the development of partial differential equations that capture that physics. As such, the work fits squarely within the EPSRC research
areas of (i) Biological Physics and Soft Matter, (ii) Mathematical Biology, and (iii) Complexity Science. In this project, the focus is on eukaryotic organisms known as plant-animal worms, whose large size (millimetres) and distributed
source of motility (ciliary carpets) enable experimental characterisation of the fluid dynamics of inter-organism interactions that drive the formation of remarkable macroscopic circulating vortices of coherent swimming. It will involve experimental investigations of the swimming of individual organisms, novel methods of fluid dynamics to characterise their pairwise interactions, and new experimental methods to elucidate the transition to collective behaviour as a function
of the concentration of organisms. Concurrently, the transition to collective behaviour will be described by a theoretical model derived from kinetic theory, accounting for those individual and pairwise dynamics.