John Dabiri, bioengineer at Caltech, has developed new techniques for studying the motion of aquatic animals. In a recent study in the journal Nature, Dabiri and colleagues explain how swimming animals mix the ocean. Ocean mixing is important for the distribution of gases and nutrients throughout the sea, and can even affect global climate. Video courtesy of Nature John Dabiri, Kakani Katija, John H. Costello and Sean P. Colin. Music by Aaron Kerr and Swallows. Produced by Flora Lichtman.