  The world's oceans are in constant motion, transporting the sun's heat from
the equator to the poles, bringing marine life fresh supplies of oxygen and
nutrients, and sequestering nearly half of our carbon dioxide emissions since
the Industrial Revolution. Within this dynamic aquatic milieu exists another
type of motion: the perpetual teeming of trillions of swimming animals. Are
these organisms simply along for the ride, carried by the prevailing ocean
currents and occasionally using their powers of locomotion to explore their
surroundings; or could their propulsion result in dynamical feedbacks that
influence the physical and biogeochemical structure of the ocean itself?
