Abstract:
Filamentous cyanobacteria can show fascinating patterns of self-organization, which however are not well-understood from a physical perspective. We investigate the motility and collective organization of colonies of these simple multicellular lifeforms. As their area density increases, linear chains of cells gliding on a substrate show a transition from an isotropic distribution to bundles of filaments arranged in a reticulate pattern. Based on our experimental observations of individual behavior and pairwise interactions, we introduce a model accounting for the filaments' large aspect ratio, fluctuations in curvature, motility, and nematic interactions. This minimal model of active filaments recapitulates the observations, and rationalizes the appearance of a characteristic lengthscale in the system, based on the Peclet number of the cyanobacteria filaments.
Biography:
Prof Lucas Goehring is a Professor of Physics in Nottingham Trent University, UK. He is an expert in non-linear dynamics and pattern formation, with a focus on multi-phase flows and interdisciplinary research. He has a proven talent for working at the interface between soft matter physics and other areas including biology, the earth sciences and heritage science. He is most proud of his work on geophysical patterns, where his research has helped explain:
the scaling of columnar joint, such as the Giant's Causeway,
the dynamics of permafrost crack patterns on Earth and Mars,
the formation of Precambrian fossils as hydrodynamic instabilities,
the patterning of salt crusts in dry lakes, and
the failure of materials from artificial sandstone to avalanches.