Rotation and Deformation Dynamics of Analog EPS Particles in Turbulent Flow

Marine snow particles are organic particle aggregates that occur in the ocean, consisting primarily of detrital material, stabilized by extracellular polymeric substances (EPS). These aggregates mediate key processes in the marine carbon cycle through their aggregation, deformation, and fragmentation under turbulence. This study examines the deformation and rotational dynamics of EPS-like viscoelastic particles composed of Xanthan Gum (XG), suspended in controlled turbulence, to further understand the role of turbulence on the transport dynamics of marine snow. XG particles with concentrations ranging from 0.3125 g/L to 2.5 g/L in water exhibit non-Newtonian shear-thinning behavior and morphological transformations driven by fluid stresses. The evolving geometry, quantified via aspect ratio, deformation dynamics, and the emergence of necking structures are correlated with shear intensity and particle viscosity. Rotational kinematics are resolved by tracking particle orientation over time, revealing time-dependent re-orientation and angular displacement. Internal particle motion is investigated by embedding neutrally buoyant tracers to assess bulk motion and viscoelastic stress localization, providing new insights into turbulence-driven breakup mechanisms and EPS-mediated carbon flux in aquatic systems.