The mixing of the oceans is crucial to ensure heat, oxygen, nutrients and pollutants are moved between different layers.

While previous studies have shown how winds and tides drive most of this mixing, until now, little has been known about the contribution made by animals.

In their study, the team monitored water turbulence in Ria de Pontevedra, a bay in the north-west coast of the Iberian Peninsula, for 15 days.