Dr. Peter Franks, Scripps Institution of Oceanography
Patch formation is a ubiquitous and important strategy influencing
fundamental biological processes such as sex, predation and infection.
Patches can be formed slowly through growth and reproduction, or more
rapidly through behavior. In the ocean, patches of plankton can be so
dense that they color the water, often with sharp, dynamic boundaries. The
formation of such dense patches by organisms with only limited knowledge
of their immediate surroundings has intrigued scientists for a century.
Because the measurement of plankton swimming behaviors in situ is
difficult, the dynamics underlying the formation of such patches have been
conjectural. Using a swarm of 16, non-interacting, plankton-mimicking
robots programmed with a simple vertical swimming behavior we show the
spontaneous formation of patches of robots through their response to
internal waves in the ocean. This work demonstrates that simple swimming
behaviors can combine with ambient currents to create predictable patches,
and advances our understanding of the time and space scales governing the
intensity of biological dynamics in the ocean.