An Ocean without Barriers

By Ewa Karczewska

‘It’s still dark. I looked at my watch. It’s only 2.30am. I can’t sleep. The ship is rolling so much. I am constantly moving up and down in my bed. I have hit my head on the wall a few times already! I’m tired. To try to get back to sleep, I listen to an audio book, but it doesn’t help. Eventually, I fall asleep again at 5am only to wake up again to start my shift at 8am – I’m on the Southern Ocean, crossing one of the most turbulent parts of the Ocean, the Drake Passage, off Antarctica. No wonder it’s rolling so much!’

st_DSC00599_rMy name is Ewa Karczewska. I’m a PhD student working jointly with the University of Cambridge and the British Antarctic Survey. The focus of my research is to get a better understanding of the dynamics of the Southern Ocean, off Antarctica, which is the key to understanding the past, present and future Carbon Dioxide (CO2 ) uptake by the ocean. This is very important for understanding the processes involved in climate change. One of the major characteristics of the Southern Ocean is that it has no land barriers and therefore links the Pacific, Atlantic and Indian oceans together. This link plays a crucial role in the circulation of the Southern Ocean around Antarctica and hence on the global transport of water masses with climatologically important tracers such as CO2.

As part of my research project, I had an opportunity to conduct ocean studies for two months off the coast of Antarctica in the Southern Ocean. This research cruise was part of the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES), which is a joint US and UK project (

st-PathA group of scientists  (the lucky ones) set off from London to Punta Arenas, Chile. We then flew to Rothera, the UK Research Station located on the Antarctic Peninsula, on the De Havilland Canada Dash-7 (DHC-7), which makes regular flights to Antarctica.

The view from the plane was spectacular. When we landed, I couldn’t believe that I had come as far south as Antarctica, a place where not many people have ever had the chance to travel. It was surprisingly warm, zero degrees – the end of the summer season. We had the chance to spend two days at the base, admiring the wildlife (penguins, seals, sea lions) before the ship, the James Clark Ross, came to collect us to begin our work. There are webcams mounted on the ship which make it possible to follow its journey. The images are updated every 15 minutes and can be seen here:


When sailing through the channels and islands up to the north of the Antarctic Peninsula, we had the chance to appreciate the spectacular view of white and uninhabited mountains. At the very top of the Peninsula, we passed by the famous island, Elephant Island, where Ernest Shackleton and his crew found refuge after losing their ship, Endurance, in the ice of the Weddell Sea. Once we got on the open ocean, we began our work.

st_DSC02332_rWe would work 8 hours a day, 7 days a week, with some breaks, depending on the schedule and the weather conditions. During my shift, I was responsible for operating the CTD, which measures the Conductivity, Temperature and Depth of the ocean in real time, integrated into an array of 24, 10-litre bottles. The CTD would reach the bottom of the ocean and collect the water into the bottles from predetermined depths. Water samples would be used for analysis of different tracers.

The DIMES experiment began in 2009, when an inert chemical compound was released 1.5km below the sea surface, west of the Drake Passage into the Antarctic Circumpolar Current. Since then, the concentration of the tracer has been measured every year to see how it has spread horizontally and vertically. As a result, we now have a better understanding of the mixing dynamics occurring in the Southern Ocean.


In my everyday work in Cambridge I run theoretical ocean models with observational data to study the dynamics of the Southern Ocean, unlike the work on the cruise. Therefore, I am especially grateful for such an opportunity. I have learned a great deal about the instruments used on the ship for different research projects, data analysis and data processing. The experience of working on the ship also enabled me to see how vast the Southern Ocean really is! It has shown me how challenging it might be to collect observational data.


During the storms it was impossible to work, and even during calmer periods, the ship would roll and pitch a lot which would make the work very difficult. The surrounding environment was continuously changing. One day we would be sailing through the stormy seas, the next day it would be calm. Some days we would be going through an icy Weddell Sea, where the temperature reached -23 degrees (with a cold wind it felt even colder) and other days, sailing south of South Georgia, the temperature reached 10 degrees.

st_DSC00759_rFor some people those contrasts, simple routine, having only 40 people on board and a very slow internet access (meaning no internet access!) would be a challenge, but for me it was enjoyable and very much appreciated. Being far away from the busy cities and constant flow of information, I could find more time for reflection and found it easier to better appreciate the little things in everyday life.

During the cruise we had the chance to see many beautiful sunsets and sunrises which are not easily seen in cities where the buildings stand in the way of the horizon. The beauty and gentleness of the wildlife captivated me every day: a constant line of albatrosses or petrels behind the ship’s stern, humpback whales coming close to the ship and flipping their fins or showing their noses, penguins graciously fighting against the waves.


Even though at times it was not easy to work on the ship, as it rolled and pitched quite a lot, the beautiful views and the rare wildlife made me forget about those difficulties very quickly. The cruise was an incredible place to learn about the science of the Southern Ocean. This adventure of a lifetime was educational and personally enriching, and left me with some great memories.


‘It’s still dark. I looked at my watch. It’s only 2.30am. The ship is very stable, not moving from side to side or up and down. But there is that constant noise, cracking and squeaking. I can’t sleep. It’s too loud. I’m tired. To get back to sleep I listen to an audio book, but it doesn’t help. Eventually, I fall asleep again at 5am only to wake up again to start my shift at 8am – we are on the Weddell Sea, no wonder it’s calm and loud, we are sailing through ice!’