Deep-diving robots to study carbon absorption of "marine snow" algae
As tiny carbon-hungry organisms, algae play an important role in removing CO2 from the atmosphere, and a first-of-a-kind research expedition is set to highlight just how important that role might be. With a fleet of advanced deep-diving robots, scientists will pay a visit to the seafloor to investigate the load carried by dead algae falling to the depths of the ocean as “marine snow.”
Algae such as phytoplankton are a key cog in the natural climate cycle machine, converting sunlight and carbon dioxide into energy to keep things in balance. This new research expedition will focus on algae that has reached the end of its life and has sunk from the upper layers of the ocean to its depths, taking a portion of carbon along for the ride.
“The microscopic algae in the ocean are responsible for removing carbon dioxide from the atmosphere as much as the forests on land are,” says Voyage Chief Scientist, Professor Philip Boyd, of the Australian Antarctic program Partnership. “When they die, these tiny carbon-rich particles fall slowly to the ocean floor like a scene from a snow globe. We are excited about how this combination of new imaging sensors will allow us to get a larger and much clearer picture of how ocean life helps to store carbon. It’s a bit like an astronomer who has only been able to study one star at a time suddenly being able to observe the galaxy in three-dimensions.”
These advanced sensor systems will be fitted to robotic floats that plunge to the depths of the Southern Ocean to image the algae. Combined with observations from a research vessel and satellite measurements, this will provide a clearer picture of the density of the algae at various depths, and in turn increase our understanding of what scientists call the “carbon pump,” or the transfer of carbon from the atmosphere into the ocean.
“We are just beginning to understand how the biological carbon pump works, but we know it helps in the removal of about a quarter of all the carbon dioxide that humans emit by burning fossil fuels,“ says Boyd. “During the voyage, we will deploy a fleet of deep-diving robotic floats and gliders that use new bio-optical sensors to ‘photograph’ the density of the algae at different depths. When they return to the ocean surface, these floats will immediately transmit their data back to us via satellite. It is a major step forward in our ability to measure carbon uptake by marine life.”
Named the Southern Ocean Large Areal Carbon Export voyage, the expedition departed last Friday, and will wind up on January 16, 2021.