Oxford Martin School

Dr Helen Johnson, Associate Fellow at the 21st Century Ocean Institute, recently returned from a month-long trip to the Canadian Arctic Archipelago.

She recounts her experiences below:

A long cold night shift doesn't seem so bad when the sun never sets. And who would want to sleep anyway when there are icebergs all around and the possibility of seeing a polar bear?! I was lucky enough this summer to spend a month aboard the Canadian coastguard icebreaker the CCGS Henry Larsen, engaged in oceanographic research in the narrow channels of the Canadian Arctic Archipelago. It's a magical, inspiring, fascinating place to spend a summer! And the measurements we make are helping us to understand more about the ocean connections between the Arctic and the Atlantic, and their role in the global climate system.

I've been involved with the Canadian Archipelago Throughflow project, funded by the US National Science Foundation and the Canadian International Polar Year, since it began in 2003. The project aims to measure and understand the flow of freshened sea water and ice from the Arctic into the North Atlantic through Nares Strait to the west of Greenland, and the other channels of the Canadian Archipelago. Changes in this fresh water input have the potential to affect global ocean circulation, and hence both European and global climate, yet we know surprisingly little about the ocean circulation in this remote corner of the globe. Partly because this is such a difficult place to do science! Packed with multi-year ice that is land-fast for much of the year, Nares Strait is only accessible, even to icebreakers, for a narrow window of time each summer. Which means that we try to use every hour of time on board the ship to take measurements aimed at understanding the complex ocean dynamics and the atmosphere-ice-ocean interactions in the region.

Our principle goal this year was to recover 12 oceanographic moorings deployed in 2007. These have been taking measurements of ocean temperature, salinity and current, as well as sea-ice thickness, faithfully every 15 minutes over the two years. The instruments are attached to heavy anchors on the seabed by hooks which open when they receive a coded sound signal from the ship. They then pop up to the surface, allowing us to download the data, service the instruments, and re-deploy them for another stint.

Over the month we've also measured more than a hundred vertical profiles of temperature and salinity, taken dozens of water samples which will later be analyzed chemically in the lab, and deployed or serviced several weather stations. The ice team on board have drilled through over 2 km of multi-year sea-ice, measuring the thickness and properties of ice floes as they move southwards and gradually melt. And we've taken some of the first oceanographic measurements at the floating tongue of one of Greenland's outlet glaciers. No wonder I feel as if I haven't slept for a year! Fuelled by east coast Canadian specialities such as salt cod and brewis, and aided by the keen, talented and fun Newfoundland ship's crew, the international science team of 16 people (headed by Dr Humfrey Melling of the Institute of Ocean Sciences, British Columbia, Canada) have worked hard to pack in as much as possible.

Along the way we've seen polar bears, narwhal, walrus and seals. We've broken lots of ice, photographed amazing sunsets and worked under fogbows. We've barbecued steaks on the aft deck of the ship, and played bingo and darts with the crew. Cut-off from the rest of the world, problems and challenges with the instruments have had to be solved by those on board, using whatever we already have with us. That's made for an intense and rewarding research experience with an inspirational team of people, and reminds me of the reasons I became a scientist in the first place. And now, back in Oxford, it's time to look in more detail at some of the data! Understanding how the ocean circulation works, especially in polar regions, is an essential part of understanding the role and response of the ocean in a changing carbon cycle, the key focus of the 21st Century Ocean Institute.

A selection of photographs from Dr Johnson's trip are available to view on the 21School Flickr site.