A turbulent journey

I would be lying if I told you that I am on this cruise just because of science. My name is Espe Broullón and I am part of the IMAGE cruise because of the science, the good food and the people.

From left to right: Landscape of a fogbow and icebergs; Tony from the crew writing the delicious menu for the day; part of the scientific team having a break during the ecplise.

I am a physical oceanographer based in the University of Southampton, in the UK. My research focuses on understanding how different properties of the ocean, such as heat, freshwater and nutrients, are affected by ocean mixing. To understand how these properties are redistributed, we study turbulence: chaotic motions in the ocean that occur across a huge range of scales, from large ocean currents down to the smallest scales that we can measure.

Here in the Arctic, freshwater from rivers, melting ice and rain, entering the ocean by the surface layer, interact with the saltier and warmer Atlantic waters underneath. Turbulence and mixing play a key role in exchanging of properties between the two layers, in the same way as a spoon mixing sugar and coffee. This interaction makes the Arctic a key region for the large-scale ocean circulation and, in turn, for global climate.

To measure how turbulent the ocean is, we use a VMP—vertical microstructure profiler—which allow us to detect tiny variations in the properties of the ocean, an imprint of turbulent waters.

Deployments for turbulence measurements. From left to right: Hugo from the crew and me, next to the vertical microstructure profiler, VMP (picture by Javier Arístegui); Manuel from the crew, Manuel from UTM, myself, Camilo from UTM and Isaac from the crew, during a VMP deployment (picture by Mar Nieto Cid); Camilo from UTM, me, and Hugo and Fran from the crew, during the turbulence float deployment (Photo: María Fernanda Montero).

Another way to study turbulence, is deploying autonomous floats equipped with similar sensors to those on the VMP. Unlike us, these floats can continue working after we leave. This is particularly useful for understanding how the ocean changes throughout the year, including during stormy periods when it is difficult—or even impossible—for us to sail through these rough waters.

The floats travel down to the deep ocean (~2000 m) and return to surface every day, drifting in the ocean following the water flow. Every time they are at surface, the floats send us data via satellite. This means that, even when we are back home, we can continue to follow what is happening in the ocean.

Yesterday, we deployed one of these floats. Before sending it into the water, we all signed it with messages of love and luck for its journey. During the deployment, I was surrounded by the whole team on board. I have never felt so supported during a deployment!

Although we will leave this place soon, the float will stay behind observing the Arctic ocean for us, long after the ship has gone. We will keep in touch with it from home, receiving its messages from the Arctic and, hopefully, learning something new from them.

So, perhaps I am here for the science, the good food and the people —but I think I will also leave with a new member of the team: a little float somewhere out there in the Arctic, carrying our messages with it as it begins its own journey.