by It’s getting dark and I’m on top of the research ship. From Maria merian, On Bridge. This is your control center, with large windows providing an uninterrupted view of the stormy sea in all directions, and long banks of screens and maps showing data channeled from inside, around, above and below the ship. Here in the open sea, it is essential to be attentive to what nature is doing. The lights are off so dark-adapted eyes can scan the waves, and the first mate uses the speakers to fill the space with smooth, calm jazz.
I hold on to the railing below the window with both hands, one leg braced against the desk behind me, as the boat rides up a wave about 26 feet (8 meters) high and then sinks on the other side. It’s like a big roller coaster; You feel yourself floating just after the peak of the wave and then, as the boat hits the trough, you tense up to resist the additional force from the ground.
While the views are spectacular, we are here in the Labrador Sea for something no human can see directly. In this northwestern corner of the Atlantic, between the southern tip of Greenland and Newfoundland, in winter – in a cold and continually stormy climate – we can live within a particular scientific phenomenon for many weeks. We are here to learn about a process that is fundamental to the functioning of our planetary engine. Around us, the ocean breathes deeply, literally. The cooling between late November and February causes deep mixing between surface waters and deep waters, facilitating vital gas transport. I am part of the British contingent of an international team of scientists who are here to study how that happens.
Our seas are doing us a huge favor by removing additional carbon from the atmosphere.
Our society tends to see the large blue expanses on maps as mere liquid fill with fish. Could not be farther from the truth. The connected global ocean is an engine, a 3D dynamic system with internal anatomy that is constantly doing things that shape the world we take for granted. It is a huge reserve of heat and gases: carbon dioxide (CO2), oxygen, nitrogen and more. And when the vast surface of the sea touches the atmosphere, these gases can transfer in both directions, changing their concentrations in the water and air.
Near the equator, for example, CO2 It leaves the water to rejoin the atmosphere, while up here, in high latitudes, it goes in the opposite direction. Currently, these processes are not balanced: the ocean is absorbing additional CO2 because we have increased the atmospheric concentration by burning fossil fuels and altering the earth’s surface. Our seas are doing us a huge favor by removing additional carbon from the atmosphere, but we don’t understand all the details of this process at the surface, or how this may change in the future.
The ocean respiration that occurs here in the Labrador Sea is particularly important because it is one of the few areas where its surface is sometimes directly connected to its depths. In most of the global ocean, the top layer of water (usually a few tens of meters thick) floats on colder, denser water below, remaining quite separate. But in this corner of the North Atlantic, in winter, the surface water cools so much that continuing storms can mix the top layer down. It’s like an open drain in the deep ocean (anything that enters the sea here can continue to go down) and this forms a crucial part of what is called the “overturning circulation”, the slow global movement of seawater between the surface and depths. One consequence is that animals that live about two-thirds of a mile below the surface and never see sunlight, from small lanternfish to giant squid, can still breathe oxygen.
Large winter storms here add oxygen to surface water, which sinks downward, then sideways, and forward toward the rest of the Atlantic, oxygenating the entire middle layer of the ocean. But our best computer models of how much oxygen flows this way don’t match what we actually measure. This is important, because the entire global ocean is slowly losing oxygen: there is now about 2% less than in the 1960s. To predict what will happen in the future and its implications, we need to understand the conveyor belt that takes it to over there.
He Maria S Merian It is a German research vessel that has 22 scientists and 24 crew on board. Each team within this collaboration of researchers from Germany, Canada, the United States and the United Kingdom is studying a different aspect of the complex respiratory process. The only way to make progress is to track the physics and chemistry of the oceans, and what the surface and atmosphere are doing, and then put the data together – putting the puzzle together once we’re back on dry land. There have been relatively few experiments that could directly measure gases moving between the atmosphere and stormy, open waters, and the last one (in which I also participated) was 10 years ago.
A decade later, we have new, more precise measurement instruments and know that we need to study a broader range of interrelated processes. This is a great opportunity and we are all aware that (for logistical and resource reasons) it will not happen again for a long time. None of this is easy: these are novel experiments in a violent environment; There is no guarantee that anything you place over the side of the boat will return intact, or that the wind and waves will allow us to carry out our plans. Every data we obtain is valuable.
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There are two methods of measuring ocean respiration, one from a tall mast placed on the bow of the ship that tracks the minutest details of wind direction and CO.2 concentration, and that depends on the measurement of the inert tracer gases that we injected into the water 10 days ago (I write at the end of December), now at concentrations of approximately one in a million trillion. Some on board continually take water samples, both from the surface as the ship zigzags, and from a variety of depths, mapping the 3D structures (masses of water distinguished by temperature or salinity) beneath us. Others have small underwater or surface vehicles, which are pulled behind the ship or “fly” short missions in the water.
I’m measuring bubbles from breaking waves at the surface (and how their sizes change over time) because they are thought to speed up the transfer of some gases to the water. The difficulty is that all the interesting bubble processes occur in the upper 2 or 3 meters, but the surface itself frequently moves up and down between 5 and 10 meters. To give me access to that awkward top layer, the mechanical engineering shop at University College London, where I work, made me a buoy that’s basically a big hollow yellow stick with a heavy base that floats upright and is mostly submerged.
Nature is rich and beautiful, but it is rarely orderly or convenient, and we have to face that.
This provides a platform for my eyes and ears just below the water line: with specialized bubble chambers, acoustic devices and dissolved gas sensors. It can float freely for several days in rough seas, following everything around it. We only have seven hours of daylight, so the buoy is always deployed at night. It takes a large crane and seven people to lift it safely into the sea, and then all you can see above the waves is the top 2 meters and its flashing white light.
There is almost always complete cloud cover, so the sky is black and the sea is black and you can’t see where they touch. The little flashing light fades into darkness, as years of work and preparation fade away and all that remains is confidence in the engineering. The beacon at the top emails me every half hour to tell me where it is, chatting in the background about my day while I try not to think about what the 50 mph wind speeds and up to 10 wave heights are like. meters can affect the buoy. The relief when we get it back a few days later is immense.
While we live in an age of technological wonder and constant information, data seems cheap. But our global ocean is gigantic, and there is no easy way to expand research into its bowels. Marine science remains incredibly data-starved, especially given that the sea is at the center of every climate model. Computer models are enormously powerful, but their job is to match the measurements we make in the real world, so we only know how well the models work if we have these critical numbers. That’s why it’s important to be here, in the messy real world, taking difficult steps and trying to challenge our understanding of what’s going on around us. Nature is rich and beautiful, but it is rarely orderly or convenient, and we have to face that.
Related: Why we should respect the last great desert on Earth: the ocean
I hope that the result of this project will be a much better understanding of the mechanisms that cause gases to move across the surface in stormy seas, and that this will mean we can calculate much more robust carbon and oxygen budgets for the ocean. This will add nothing to the strong arguments against burning fossil fuels: we already have more than enough science to know what we need to do to avoid the worst climate outcomes, and enough technology to get there.
But what this will do is help us understand and predict a changed ocean and make better decisions about how to manage the consequences of our past actions. We live on a water planet and any honest assessment of our own identity must reflect that. Ignoring the sea is not an option, so increasing our understanding of it is an essential step on the path to a better future.
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Blue Machine: How the Ocean Shapes Our World by Helen Czerski is published by Transworld (£20). to support the guardian and Observer Order your copy at guardianbookshop.com. Delivery charges may apply
