by Darkness is falling and I am up at the top of the research vessel Maria S Merian, on the bridge. This is her control center, with large windows providing an uninterrupted view of the stormy sea in every direction, and long banks of screens and maps showing funnel details from inside, around, above and below the ship. Out here in the open ocean, it’s vital to keep a close eye on what nature holds in store. The lights are off so dark-adapted eyes can scan the waves, and the first officer is using the speakers to fill the space with smooth, calm jazz.
I am holding the rail under the window with both hands, one leg braced against the desk behind me, as the ship goes up a wave about 8 meters (26 feet) high, then plunges down the other side. It’s like a big rollercoaster; you feel yourself floating just after the peak of the wave and then, as the ship hits the tank, you struggle to withstand the extra force from the floor.
Although the views are dramatic, we are here in the Labrador Sea because of something that no one can see directly. In this northwest corner of the Atlantic, between the southern tip of Greenland and Newfoundland, in winter – in the cold and always stormy weather – we can live inside a particular scientific phenomenon for many weeks. We are here to learn about a process that is fundamental to how our planetary engine works. All around us, the ocean is taking a deep breath – literally. The cooling between late November and February results in deep mixing between surface waters and the waters at depth, which facilitates the transport of vital gases. I am part of the UK delegation to an international team of scientists here to study how that happens.
Our oceans are doing us a huge favor by removing extra carbon from the atmosphere
Our society tends to see the big blue expanses on maps as just filled with liquid and fish in them. Nothing could be further from the truth. The connected global ocean is an engine, a dynamic 3D system with an internal anatomy that is constantly Doing things that shape the world we take for granted. It is a huge reservoir for heat and gas: carbon dioxide (CO2), oxygen, nitrogen and more. And when the vast surface of the sea comes into contact with the atmosphere, these gases can be transferred in both directions, changing their concentration in the water and in the air.
Near the equator, for example, CO2 that comes out of the water to re-enter the atmosphere, and up here in the high latitudes, it goes the other way. These processes are currently unbalanced – additional CO is being taken up by the ocean2 because we have increased the atmospheric concentration by burning fossil fuels and changing the surface of the earth. Our oceans are doing us a huge favor by removing extra carbon from the atmosphere, but we don’t understand all the details of this process on the surface, or how this might change in the future.
The ocean respiration that occurs here in the Labrador Sea is of particular importance because this is one of the few areas where its surface is sometimes directly connected to its depth. Over most of the world’s oceans, the top layer of water (usually a few tens of meters thick) floats on cooler, denser water below, remaining relatively isolated. But in this corner of the north Atlantic in winter, the surface water cools so much that the continuous storms can mix the top layer far down. It’s like a plug hole opening into the deep ocean – anything that goes into the sea here can keep going down – and this is a vital part of what’s called the “undoing cruise”, the global swing slow sea water between the surface and the depth. One of the consequences is that animals that live about two-thirds of a mile below the surface and never see sunlight, from the petite lanternfish to the giant squid, can still breathe oxygen.
Large winter storms at this location add oxygen to the surface water, which flows down, then sideways and on into the rest of the Atlantic, oxygenating the entire mid-ocean layer. But our best computer models of how much oxygen flows this way differ from what we actually measure. This is important, because the entire global ocean is slowly losing oxygen – it is about 2% less now than in the 1960s. To predict what will happen in the future and the implications of it, we need to understand the conveyor belt that finds it there.
The IS Maria S Merian it is a German research vessel, with 22 scientists and 24 crew on board. Each team within this collaboration of researchers from Germany, Canada, the US and the UK is studying a different aspect of the complex breathing process. The only way to make progress is to keep track of ocean physics and chemistry, and what the surface and atmosphere are doing, and then put the data together – put the pieces together puzzles together when we are back on dry land. There have been very few experiments that could directly measure gases moving between the atmosphere and open storm waters, and the last one (which I was also involved in) was 10 years ago.
Ten years later, we have new and more accurate measurement tools and know that we need to study a wider range of interconnected processes. This is a huge opportunity, and we all know (for logistical and resource reasons) that it won’t come again anytime soon. None of this is easy: these are novel experiments in a violent environment; there is no guarantee that anything you put over the side of the ship will return safely, or that the wind and waves will allow us to carry out our plans. Every piece of data we receive is valuable.
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There are two methods of measuring ocean respiration, one from a tall mast located on the bow of the ship that tracks the smallest details of wind direction and CO.2 concentration, and one that depends on the measurement of an inert tracer gas that we injected into the water 10 days ago (I’m writing in late December), now at a concentration of about one in a million billion. Some of them are on board continuously taking water samples, from the surface as the ship passes, and from a range of depths, mapping the 3D structures (water masses of varying temperature or salinity) below us. Others have small underwater or surface vehicles, towed behind the ship or short “fly” missions in the water.
I am measuring the bubbles from waves breaking on the surface – and how their sizes change over time – as these are thought to accelerate the transfer of some gases into the water. The difficulty is that all the interesting bubble processes are happening in the top 2 to 3 meters, but the surface itself is often moving up and down between 5 and 10 meters. To give me access to that top layer, the mechanical engineering workshop at University College London, where I’m based, made me a buoy which is basically a large hollow yellow stick with a heavy base that floats upright and is under mostly water.
Nature is rich and beautiful, but it’s rarely tidy or convenient, and we need to face that
This provides a platform for my eyes and ears just below the waterline: with specialized bubble cameras, acoustic devices and dissolved gas sensors. It can swim freely for several days in heavy seas, tracking everything around it. We only have seven hours of daylight, so the buoy is always used at night. It takes a big crane and seven people to get it safely over the side into the sea, and then you can see above the waves that it is 2 meters high with its bright flashing light.
There is almost always full cloud cover, so the sky is black and the sea is black and you can’t see where they touch. The small glimmer of light fades into darkness, as the years of work and preparation float away and all that remains is confidence in engineering. The beacon on top emails me every half hour to tell me where it is, chatting in the background of my day as I try not to think about what wind speeds of 50mph and wave heights of up to 10 meters will do to the buoy It is a great relief when we recover it a few days later.
Although we live in an age of technological wonder and constant information, data seems to be cheap. But our global ocean is huge and there is no easy way to expand the investigation of its interior. Marine science is still extremely data poor – especially since the sea is at the heart of all climate models. Computer models are incredibly 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 real world, making difficult guesses and trying to challenge our understanding of what’s happening around us. Nature is rich and beautiful, but it is rarely tidy or convenient, and we need to face that.
Related: Why we need to respect Earth’s last great wilderness – 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 that 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 plenty technology to get us most of the way.
But what this will do is help us understand and predict a sea of change 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 a vital step on the way to a better future.
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Blue Machine: How the Ocean Shapes Our World by Helen Czerski published by Transworld (£20). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply
