Tabular Iceberg in the Antarctic Ocean
My name is Damien Guihen and I work for the British Antarctic Survey in Cambridge, UK. I am an oceanographer and study the interaction of physical processes with biological systems. At the moment I am part of a project called GENTOO, which stands for Gliders: Excellent New Tools for Observing the Ocean. The project is named after a species of penguin and is a partnership between the University of East Anglia (UEA), the British Antarctic Survey, Caltech in the US and the University of Cambridge. Together we are trying to use special robots that dive as deep as 1000 m underwater to learn more about how the ocean works in the Antarctic and particularly around the Antarctic Peninsula, that part of land that juts out of the frozen continent and stretches towards South America.
The robots being used are called ocean gliders. These gliders use changes in an oil bladder to sink or float and have short wings that move them forwards. We put the gliders in the water for periods as short as a day or as long as six months. They are very efficient and can take measurements for long periods using a range of sensors. A glider uses a satellite to call home every time it comes to the surface. It phones a computer in the UK and uploads its data. Then it asks for new instructions. This way, we can see the data very quickly and can control it from anywhere in the world.
Damien with an ocean glider
Ocean glider deployment map shows the path taken by the ocean glider, west of the South Orkney Islands. The breaks between the red lines are when the glider is at the surface
The partners in the project are investigating different aspects of the ocean. UEA are using the high resolution temperature and salinity data from gliders to understand the different layers of water and how they interact. The Southern Ocean is very cold and dotted with countless icebergs, great and small. The cold causes water to sink and this sinking drives a lot of ocean flows. Using the glider allows UEA to take hundreds of thousands of measurements that help them to build a better picture of what is happening. Caltech are using the gliders, along with some floating instruments called drifters, to measure how the water in the southern ocean is mixing and moving. They have tracked some drifters for thousands of kilometres, from the Antarctic Peninsula to South Georgia. The University of Cambridge team are using the data collected to help build better mathematical models of how the water moves so that they can better describe and predict the mixing, particularly on slopes and near the icebergs.
At the British Antarctic Survey, we are using a special instrument that has been built into the glider. The instrument, called an echo sounder, sends little pings of sound. It then listens to the echo that comes back from small animals in the ocean. As the glider moves around, we collect a lot of data from the pings in different locations and at different depths. We can then use this data to build a picture of the distribution of these animals throughout the ocean. Using the data from the other groups, we can get a better idea how the ocean currents push the animals about and how a changing climate might effect the Antarctic marine ecosystem.
Working on a ship or a base in the Antarctic is always fascinating. Sometimes we have to crash our way through thick ice to get to where we need to go. We see a lot of ice bergs too and each one looks different. We often see large storms that keep us up at night as the ship rolls its way through big waves. We are fortunate too to see a lot of wildlife such an albatross, giant petrels, cape petrels, skuas, orca (killer) whales, elephant seals, crab-eater seals, Weddell seals, fur seals, and penguins such as gentoo, chinstrap, king, Adele and Magellanic. It’s a wonderful experience and each time I come back I count the days until I can go again.
Albatross in the sunset
A very big thank you goes out to Dr Damien Guihen of the British Antarctic Survey for sharing his experiences and photographs from the Antarctic with us the readers of this blog! The post has given a fascinating insight into the work of BAS in one of the most remote and undiscovered continents on the planet.