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Autonomous underwater vehicles observing ocean physics and ecosystems.
Autonomous underwater vehicles observing ocean physics and ecosystems.
Glider on R/V Nanuq.
Glider inspection by an albatross.
Glider near R/V Sikuliaq.
The Slocum Glider is an autonomous underwater vehicle (AUV) designed for long-duration missions at sea. Gliders are buoyancy-driven: they adjust their buoyancy to slowly sink or rise through the water column. Small wings convert this vertical motion into forward movement, allowing the glider to travel efficiently for weeks to months at a time on very little energy.
Each glider is equipped with a suite of scientific sensors that measure key ocean properties such as temperature, salinity, dissolved oxygen, chlorophyll, and currents. As the glider repeatedly dives and climbs, it collects a vertical profile of the water column, building a three-dimensional picture of ocean conditions over time.
Every few hours, the glider surfaces to determine its position via GPS and transmit its location and collected data through satellites. This real-time connection allows researchers to monitor the mission, update the glider’s path, and immediately apply the observations to ongoing studies of ocean circulation, climate, and ecosystems.
How do gliders work? Watch this animation to learn more!
How do gliders work? Watch this animation to learn more!
A Snapshot of our Projects
A Snapshot of our Projects
Glide-365
Through the Glide-365 project, we monitored the mid-shelf Gulf of Alaska Ecosystem Observatory continuously for over a year using Slocum gliders. To achieve this, gliders were rotated in and out like a relay team, ensuring uninterrupted observations across all seasons.
Each glider carried sensors to measure temperature, salinity, dissolved oxygen, and chlorophyll throughout the water column. A full year of uninterrupted, high-resolution measurements allows us to capture short-term events—such as storms, mixing, and phytoplankton blooms—while also revealing the slower, seasonal cycles that shape the ecosystem. This kind of record is rare in oceanography, where ship-based sampling often provides only brief snapshots in time. Glide 365 demonstrates how autonomous vehicles can transform our ability to study ocean variability and long-term change.
Spring Bloom in the NGA
Spring Bloom in the NGA
Each year in the Northern Gulf of Alaska (NGA), the transition from winter to spring triggers one of the ocean’s most important events: the spring phytoplankton bloom. With increasing sunlight and favorable conditions, microscopic algae grow rapidly, fueling a burst of productivity that supports the entire marine food web—from tiny zooplankton to fish, birds, and whales.
To study this critical event, we deploy a glider during the winter–spring transition to capture the timing, magnitude, and structure of the bloom. This glider carries a shadowgraph, which takes high-resolution images of plankton in the water column, along with an EK80 echosounder, which provides acoustic data to detect and quantify plankton distributions. By combining these advanced measurements with physical and chemical observations, we can better understand how spring blooms vary from year to year, what drives their dynamics, and how they shape the broader ecosystem.
Shadowgraph plankton image collected by a glider.
Chuckchi Sea Mammal Observing
Chuckchi Sea Mammal Observing
In addition to measuring ocean conditions, one of our gliders is specially equipped with a hydrophone that allows it to listen to underwater sounds. This glider records the sounds produced by whales, walrus, and other marine mammals. The recordings are later analyzed by acoustic experts to identify species, track their movements, and better understand how marine mammals use different parts of the ecosystem.
This approach allows us to monitor marine life in areas and seasons where direct observations from ships or aircraft are difficult. Long-duration glider missions provide a unique opportunity to document animal presence alongside the physical and biological conditions of the ocean, giving us a more complete picture of the ecosystem. Learn more about our 2025 deployment and explore archived missions here
Alaska Ocean Observing System provides real time data visualizations of our glider deployments.
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