Coordination and dynamics of interfacial living tangles

Living tangled matter is ubiquitous across lengths scales, from chromosomal DNA and fungal filaments to worm blobs. Understanding how the interplay between topology, elasticity and fluid dynamics enables coordination in entangled living systems continues to present fundamental challenges. Here we study the collective dynamics of floating buoy structures made by California blackworms (Lumbriculus Variegatus) in shallow water, which consist of a submerged tangled aggregate of worms suspended from the air-water interface by their tails. By combining experimental and theoretical approaches, we demonstrate that aerotaxis drives worms towards the interface, where surface tension forces constrain their locomotion, resulting in the self-assembly of the buoy state. Structurally, we further show that the interface constrains the buoy to be an anisotropic tangle. We then illustrate how the topological dynamics of the resulting polarized tangles produces emergent collective motions, including vertical lift and horizontal locomotion. Our results provide guidance for designing and assembling functional topological materials.