Efficient survival strategy for zooplankton in turbulence

TL;DR

This paper presents a simple, robust strategy for zooplankton to avoid turbulence by sensing strain gradients, leading to spatial clustering and flow alignment that enhance survival and reproductive success.

Contribution

It introduces a novel, efficient hydrodynamic sensing strategy based on strain gradient sign detection for zooplankton in turbulent environments.

Findings

Zooplankton cluster strongly when following the strategy.

They align against local flow velocity, aiding mate finding and feeding.

The strategy helps reconcile predator detection with turbulence avoidance.

Abstract

Zooplankton in a quiescent environment can detect predators by hydrodynamic sensing, triggering powerful escape responses. Since turbulent strain tends to mask the hydrodynamic signal, the organisms should avoid such regions, but it is not known how they accomplish this. We found a simple, robust, and highly efficient strategy, that relies on measuring the sign of gradients of squared strain. Plankton following this strategy show very strong spatial clustering, and align against the local flow velocity, facilitating mate finding and feeding. The strategy has the potential to reconcile competing fitness pressures.