https://www.sciencedaily.com/releases/2021/02/210226103816.htm

Researchers from the USC Viterbi School of Engineering found that sea stars effectively stay attached to surfaces under extreme hydrodynamic loads by altering their shape. The researchers, including the Henry Salvatori Early Career Chair in Aerospace and Mechanical Engineering Mitul Luhar and doctoral student Mark Hermes, found sea stars create a "downforce" due to their shape. This mean that instead of being lifted by the flow forces, the sea stars are pushed downward toward the rock or floor surface they are on.

Sea stars are incredibly adaptive, said Luhar, assistant professor in the USC Viterbi Department of Aerospace and Mechanical Engineering. "When there is high wave activity and high water forces, sea stars will grow skinnier and take on a lower profile. When the sea star is transported to a sheltered environment with lower hydrodynamic forces, they pop up a bit and their cross sections get bigger."