EAGER: Characterizing vertical swimming, payload capacity, and performance envelope of biohybrid robot jellyfish as future ocean monitoring platforms

In light of a changing climate, the need to monitor, map, and model the health of the ocean and its closely associated ecosystems is more vital than ever. Biologging, i.e., the use of animal-attached sensors to collect data on animal behavior, physiology, and their surrounding environment, has become an important input for many climate change and ocean assessment models, providing environmental data on regions of the ocean that would be otherwise inaccessible.

However, a major limitation of biologging is that it only provides data at locations where the animal actively swims or is passively carried. Biohybrid robotic control, or the ability to steer a living animal along a desired trajectory, would address current limitations in both biologging and traditional robotic sensing systems. Recent technology developed at Caltech has demonstrated the ability to robotically control the unidirectional swimming of a moon jellyfish (Aurelia aurita) in the laboratory and ocean.

A small microcontroller with two electrodes inserted into the center of the jellyfish induces electrical stimulation that allows for these biohybrid robotic jellyfish to swim on command and at speeds 3 times their natural abilities. These biohybrid robot jellyfish have to the potential to expand vertical ocean profiling missions in particular, where existing technology is especially constrained.

The deep ocean is vastly under-sampled due to limitations associated with immense pressure and depth and their associated technological expense. However, deep sea measurements are extremely important for understanding the interplay between the ocean and climate. Jellyfish are naturally suited to the harsh conditions of the deep, and biohybrid robot jellyfish swim at speeds an order of magnitude larger than background vertical currents due to upwelling and downwelling.

Biohybrid robotic jellyfish platforms would address many of the limitations of current ocean profiling technologies, due to their: 1) low cost, 2) global animal availability and open-source technology, 3) energy-efficient, long-duration propulsion, 4) limited environmental disturbance (small size and minimal wake), and 5) potential for deployment in large swarms. The societal broader impacts for this work include the creation of a more economically accessible, vertical profiling ocean sensing platform.

Once the performance envelope of this platform is characterized in this project, new biologging tags with additional sensors, antennas, and GPS can be incorporated. Because this technology will be open source, other researchers will be able to modify and further optimize this platform. On a local scale, this research will engage with the community through the direct mentorship of underrepresented students, as well as researcher participation in workshops focused on increasing the diversity of this research community.

The first-generation prototype of the biohybrid robotic jellyfish has demonstrated significant but unrealized potential to act as a future ocean sensing platform that can supplement and enhance existing ocean sensing technologies. However, further research and development is needed to optimize the protocol for equipping biohybrid jellies with environmental sensing tags for long-term, vertical ocean profiling under realistic field conditions.

This project will characterize the capabilities of a modified version of biohybrid robotic jellyfish for the specific application of vertical ocean profiling. Research activities will include: 1) simplifying the swim controller interface for a more plug-and-play, globally scalable controller, 2) quantifying the scaling of maximum payload versus body size for biohybrid robot jellyfish, 3) integrating an off-the-shelf biologging tag (iTAG) with the swim controller interface, 4) assessing the achievable measurement duration and spatial range of biohybrid jellyfish for long-term deployments, and 5) demonstrating successful onboard control and data retrieval of equipped biohybrid robot jellyfish for vertical ocean profiling in coastal and open ocean environments in southern California.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.