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The ocean twilight zone could store vast amounts of carbon captured from the atmosphere – but first we need to build a 4D system to track what's going on down there

Peter de Menocal, Director, Woods Hole Oceanographic Institution, The Conversation on

Published in Science & Technology News

We envision a central hub in the middle of an ocean basin where a dense network of intelligent gliders and autonomous vehicles measure ocean properties including carbon and other vital signs of ocean and planetary health. These vehicles can dock, repower, upload data they’ve collected and go out to collect more. The vehicles would be sharing information and making intelligent sampling decisions as they measure the chemistry, biology and environmental DNA for a volume of the ocean that’s really representative of how the ocean works.

Having that kind of network of autonomous vehicles, able to come back in and power up in the middle of the ocean from wave or solar or wind energy at the mooring site and send data to a satellite, could launch a new era of ocean observing and discovery.

We’re already doing much of this engineering and technology development. What we haven’t done yet is stitch it all together.

For example, we have a team that works with blue light lasers for communicating in the ocean. Underwater, you can’t use electromagnetic radiation as cellphones do, because seawater is conductive. Instead, you have to use sound or light to communicate underwater.

We also have an acoustics communications group that works on swarming technologies and communications between nearby vehicles. Another group works on how to dock vehicles into moorings in the middle of the ocean. Another specializes in mooring design. Another is building chemical sensors and physical sensors that measure ocean properties and environmental DNA.

This summer, 2023, an experiment in the North Atlantic called the Ocean Twilight Zone Project will image the larger functioning of the ocean over a big piece of real estate at the scale at which ocean processes actually work.

We’ll have acoustic transceivers that can create a 4D image over time of these dark, hidden regions, along with gliders, new sensors we call “minions” that will be looking at ocean carbon flow, nutrients and oxygen changes. “Minions” are basically sensors the size of a soda bottle that go down to a fixed depth, say 1,000 meters (0.6 miles), and use essentially an iPhone camera pointing up to take pictures of all the material floating down through the water column. That lets us quantify how much organic carbon is making its way into this old, cold deep water, where it can remain for centuries.

For the first time we’ll be able to see just how patchy productivity is in the ocean, how carbon gets into the ocean and if we can quantify those carbon flows.

 

That’s a game-changer. The results can help establish the effectiveness and ground rules for using CDR. It’s a Wild West out there – nobody is watching the oceans or paying attention. This network makes observation possible for making decisions that will affect future generations.

Humanity doesn’t have a lot of time to reduce carbon emissions and to lower carbon dioxide concentrations in the atmosphere.

The reason scientists are working so diligently on this is not because we’re big fans of CDR, but because we know the oceans may be able to help. With an ocean internet of sensors, we can really understand how the ocean works including the risks and benefits of ocean CDR.

This article is republished from The Conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts. Like this article? Subscribe to our weekly newsletter.

Read more:
Nations are pledging to create ocean preserves – how do those promises add up?

Geoengineering the ocean to fight climate change raises serious environmental justice questions

Peter de Menocal is the president and director of Woods Hole Oceanographic Institution.


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