“School” of Robots

Current methods of capturing reliable three-dimensional data on ocean currents and marine life are limited — not to mention expensive. But oceanographers at UC San Diego have designed a swarm of low-cost, underwater robots to study small-scale environmental processes and answer important questions about the most abundant form of ocean life — plankton.

Dubbed miniature autonomous underwater explorers (M-AUEs), the grapefruit-sized robots are equipped with a variety of sensors to monitor surrounding conditions while they swim up and down by adjusting their buoyancy. In a recent experiment, 16 M-AUEs were programmed to study how plankton form dense patches, which often surface as harmful red tide blooms. It has been theorized that the free-floating organisms increase their concentrations to better protect themselves from predators, as well as aid feeding and reproduction, by utilizing the giant, slow-moving internal waves below the surface of the ocean.

The M-AUEs were deployed over a 300-meter (nearly 1,000-foot) diameter area, collecting three-dimensional location data every 12 seconds. Over the course of five hours, the swarm formed a tightly packed patch in the internal wave troughs, which dispersed over the crests of waves, similar to the way red tides are observed. This confirms that plankton use the physical dynamics of the ocean to increase their concentrations, and opens up a whole new field of exploration for studying marine life, as well as monitoring oil spills, sewage outlets and small-scale circulation in rivers or coastal areas.