Photo: Scripps Institute of Oceanography
Researchers at the Scripps Institute of Oceanography (UC San Diego) have created an innovative new tool that blends robotic technology with oceanography to answer questions about one of the ocean’s most abundant life forms – plankton.
Planktonic organisms serve many important functions in the ocean, including fueling ocean food webs and cycling essential nutrients. However, there are still much to be discovered about their movement, dispersal, and impacts on larger organisms and ecosystems. Studying the movement of individual plankton has remained particularly elusive to ocean scientists due to their small size. Researchers have hypothesized that plankton may form dense patches under the ocean surface as a way to feed, reproduce, and seek protection from predators. The current study from Jaffe and colleagues at SCRIPPS university sought to answer this question in a unique way.
A new technology – known as “miniature autonomous underwater explorers (M-AUEs), was developed by Jules Jaffe and colleagues at Scripps. M-AUEs are robots approximately the size of a grapefruit and are capable of measuring temperature, depth, and other parameters in the ocean every 12 seconds. They are small, inexpensive, and can be tracked underwater using acoustic signals. M-AUEs are programmed to mimic plankton swimming behavior by adjusting buoyancy in response to the internal, subsurface ocean “waves”.
To test the hypothesis that plankton form aggregations in the ocean, researchers conducted a five-hour experiment and tracked the movement of 16 M-AUEs deployed near La Jolla California. In response to ocean movement, the M-AUEs formed aggregations in the warm waters of internal wave troughs and subsequently dispersed over the wave crests. This research provides evidence that plankton are, in fact, capable of using the physical dynamics of the ocean to congregate into “swarms” that may serve important biological functions.
Innovative research in ocean technologies, like the development of M-AUEs, may provide valuable information on the movement of larvae between habitats, tracking oil spill dispersal, and monitoring pelagic organism populations.
1. Jules S. Jaffe, Peter J. S. Franks, Paul L. D. Roberts, Diba Mirza, Curt Schurgers, Ryan Kastner, Adrien Boch. A swarm of autonomous miniature underwater robot drifters for exploring submesoscale ocean dynamics. Nature Communications, 2017; 8: 14189 DOI: 10.1038/ncomms14189