Going on a Bear Hunt in the Arctic & Fishing for Phytoplankton
Dr David McKee from the Marine Optics and Remote Sensing Group (Department of Physics) returned to the Barents Sea in April-May 2018 for the second leg of three expeditions to study the impact of sea-ice thinning and early retreat on physical and chemical processes that underpin ecosystem function. The aim was to collect data for Arctic PRIZE, one of 4 main projects in the NERC-funded Changing Arctic Ocean Programme. The project is led by colleagues from the Scottish Association of Marine Science in Oban and has partners from the Universities of Edinburgh, St Andrews and Oxford. The major modelling effort is being directed by Dr Neil Banas from the Department of Mathematics and Statistics, University of Strathclyde. One of the key strengths of the project is the very close integration with leading Arctic science experts from Norway, Canada, Germany and the USA.
Setting Sail for a Spring Bloom
The first expedition to the region in January found very low algal biomass surviving through the dark winter months. In the intervening months the PRIZE team anxiously watched data coming back from the underwater glider we deployed in January for signs of the spring bloom forming and bringing new life back to the region. After a long wait, and only shortly before departing for our April-May cruise, we finally got the news we were waiting for. The gliders reported increasing levels of Chlorophyll fluorescence, telling us that the spring bloom had started. We set sail from Tromso at the end of April knowing that the main target of our research was out there waiting for us.
The first few days at sea were pretty ‘lumpy’ as we passed through another low pressure region – quite an introduction for those of the team on their first serious research cruise. However, as we headed up into the marginal ice zone and started collecting data the seas settled and the sun shone. As we were by now anticipating, we found ourselves sampling a very healthy spring bloom. Perfect timing! The massive increase in algal biomass not only provides nutrition at the heart of the marine food web, it is also a lot easier to measure than the vanishingly small values we had previously encountered in January. Lots of happy scientists cheering on the little green guys!
Science and Nature Under the Midnight Sun
Moving further north into the sea ice we quickly found ourselves at sufficiently high latitudes for viewing the midnight sun. The contrast between our previous experience in the dead blackness of winter could not have been more stark. Now we had daylight around the clock and we found ourselves endlessly fascinated by the ever changing light and ice all around us. Even more exciting, we also got our first glimpses of some of the local stars! Seals, walruses and yes, even a polar bear were sighted as we ploughed through the ice fields.
Eventually we had to turn round and head back south as we reached a point where the ice was too thick to penetrate further. Working on the R.V. Helmer Hanssen, operated by our colleagues from the Arctic University in Tromso, is a surprisingly comfortable experience considering the hostile environment we were surrounded by. The skill and knowledge of the captain and crew is very impressive and most reassuring when you are surrounded by tonnes of moving ice!
As the ship turned south and starting the long steam to Longyearbyen on Svalbard, the team assembled on deck to admire our northernmost midnight sun. It is quite a sensation to see the sun shining at you from the north and to realise that you are looking at it across the north pole of the planet.
Sampling continued as we headed round the south tip of Svalbard and into Hornsund, a fjord on the southwest tip of Spitsbergen, the main island of Svalbard. In clear blue skies and blazing sunshine, we found one of the most beautiful unpopulated places that you can imagine. Mountains and glaciers spilling down to the sea. Ice sheets on the water’s edge marked by prints from polar bears and arctic foxes. A truly incredible place to spend a day doing science.
Back to the Future
We eventually pulled into port in Longyearbyen in Svalbard, tired after a heavy stint of making measurements, deploying a new pair of gliders and managing the disorientation caused by having no hours of darkness! The group left the ship full of expectation that we have collected an exceptional data set that covers a wide range of physical, chemical and biological elements of the Barents Sea ecosystem.
The final piece of our puzzle, observing the collapse of the bloom as nutrients are removed from the surface layer, remains to be collected on the next PRIZE cruise which sails from Longyearbyen on the RRS James Clark Ross mid-June. Dr Ina Lefering will join that cruise and report back on what they find then.