Hydrodynamic entanglement in the abyss: Morphological adaptations of groups of E. <i>aspergillum</i>

Abstract Euplectella aspergillum is a deep-sea glass sponge that has attracted the interest of the scientific community for almost 150 years, for its surprising adaptations to the asperities of the abyss. The state-of-the-art on this organism focuses on specimens in isolation, but field observations question this premise. Footage from the abyss shows instances in which E. aspergillum live in bouquets comprising several organisms. Through high performance computing of the flow physics of E. aspergillum, we discover a complex hydrodynamic entanglement that favors downstream organisms at no cost to upstream ones. Such an interaction benefits the nutrition, reproduction, and resilience of the bouquet – the first instance of a hydrodynamic advantage that emerges due to purely passive interactions in a group.