Biohybrid Robot Jellyfish act as Buoyancy-Controlled Vertical Profiling Samplers*

In light of a changing climate, monitoring ocean health is more vital than ever. Recent technology has demonstrated the ability to robotically control the unidirectional swimming of moon jellyfish. Here, we assess the potential of biohybrid robot jellyfish to act as vertical ocean profilers, similar to buoyancy-controlled Argo floats routinely used for ocean sampling. Biohybrid jellyfish equipped with positively buoyant microcontrollers and ballasts were deployed in a vertical tank and tracked swimming repeated vertical profiles (1 profile = swim down, float up). Descent speed was found to generally correlate with jellyfish volume. Biohybrid jellyfish were also tested in a coastal ocean environment, equipped with a temperature sensor to monitor the surrounding environment during profiles. The successful demonstration of vertical-profiling biohybrid robot jellyfish is an important first step toward realizing this new ocean monitoring platform. Additionally, this platform would address many of the limitations of current sensing technology due to its low cost, global availability, small size, minimal power demand, and potential scalability.