UH at MBAR Fleet of robots successfully tracks, monitors marine microbes
January 20, 2021
years of development and testing, researchers from the University of Hawai‘i
(UH) at Mānoa, Monterey Bay Aquarium Research Institute (MBARI) and Woods Hole
Oceanographic Institution have successfully demonstrated that a fleet of
autonomous robots can track and study a moving microbial community in an
open-ocean eddy. The results of this research effort were recently published in
Edward DeLong and David Karl, oceanography professors in the UH Mānoa School of
Ocean and Earth Science and Technology (SOEST) and co-authors of the study, have
been researching open ocean microbes for decades using research vessels, buoys,
satellite observations, automatic samplers and on-shore laboratories.
Two LRAUVs (Aku and Opah) and one Wave Glider (Mola) formed a coordinated system
to study the DCM. Opah and Mola followed the primary sampling robot, Aku, by
Autonomous robotic fleets enable researchers to observe complex systems in ways
that are otherwise impossible with purely ship-based or remote sensing
Tracking a moving target
Phytoplankton, photosynthetic microbes, are essential players in the global
climate system, producing roughly half of the world’s oxygen, removing carbon
dioxide and forming the base of the marine food web. There is a sweet spot in
the ocean, where light from above and nutrients from below converge to create an
ideal environment for phytoplankton. The plethora of microbes in this layer form
a ubiquitous open-ocean feature called the deep chlorophyll maximum (DCM).
Open-ocean eddies, swirling pools of water, can be over 60 miles across and last
for months. Phytoplankton thrive when these eddies spin counterclockwise in the
Northern Hemisphere and bring nutrient-rich water from the depths up toward the
“The research challenge facing our interdisciplinary team of scientists and
engineers was to figure out a way to enable a team of robots—communicating with
us and each other—to track and sample the DCM,” said Brett Hobson, a senior
mechanical engineer at MBARI and co-author of this study.
The DCM is typically found at depths of more than 300 feet, so it can’t be
tracked with remote sensing from satellites, and it’s position can shift more
than 100 feet vertically in just a few hours. This variability in time and space
requires technology that can embed itself in and around the DCM and follow the
microbial community as it drifts in the ocean currents.
DeLong noted that these teams of coordinated robotic vehicles offer a vital step
toward autonomous and adaptive sampling of oceanographic features. “Open-ocean
eddies can have a huge impact on microbes, but until now we haven’t been able to
observe them in this moving frame of reference,” he explained.
Testing robots’ tracking abilities
During the Simons Collaboration on Ocean Processes and Ecology (SCOPE) Eddy
Experiment in March and April 2018, researchers used satellite imaging to locate
an eddy north of the Hawaiian Islands. They deployed a high-tech team of three
robots—two long-range autonomous underwater vehicles (LRAUVs) and one Wave
Glider surface vehicle—from the Schmidt Ocean Institute’s (SOI) research vessel
The LRAUVs were programmed to locate, track, and sample the DCM. Using an
onboard 3rd-Generation Environmental Sample Processor (3G-ESP), on robot
collected and preserved seawater samples, allowing researchers to capture a
series of snapshots of the organisms’ genetic material and proteins.
The researchers determined that over the course of its multi-day sampling
missions, one of the LRAUVsaccurately and consistently tracked the DCMand
maintained its position within the DCM even as this biological feature moved as
much as 118 feet vertically in four hours.
Collaboration fulfilled the vision
an LRAUV with an integrated ESP that could track this feature was a milestone.
Combining that sampling power with the agility of three different robots
autonomously working together over the course of the experiment is a significant
engineering and operations achievement,” said Yanwu Zhang, a senior research
engineer at MBARI and the lead author of this study.
“This work is really the fulfillment of a decades-long vision,” said co-author
and MBARI President and CEO Chris Scholin. “Coordinating a robotic fleet to show
how microbial communities react to changing conditions is a game-changer when it
comes to oceanographic research.”
These robotic fleets are now also being used to monitor other key disturbances
to ocean health—like harmful algal blooms and oil spills.
“There is no limit to what can be achieved when you mate a team of collaborative
scientists and engineers with a co-ordinated fleet of smart robots,” said Karl.
“The future is today!”
This research is supported by the National Science Foundation, the Simons
Foundation, the Gordon and Betty Moore Foundation, the Schmidt Ocean Institute,
the David and Lucile Packard Foundation, and the State of Hawai‘i.