Day 8

Hello everyone!

My name is Sünnje Basedow, I’m the cruise leader and, together with Meng Zhou, leader of our research project Stressor. We are a great team of scientists from Norway and China, who are working together during this cruise to understand processes on the mesoscale, in particularly those that are important for the formation of zooplankton swarms.

During cruises in the last two years, we observed gigantic aggregations of zooplankton, on scales previously unknown. Those zooplankton patches occurred in surface waters along most of the northern Norwegian coast. In general, during research cruises we are looking at many processes in great detail, and this helps to understand mechanisms. But on the larger scale, we are dependent on observations by satellite and autonomous platforms. During Stressor, we combine both approaches, and hope to learn much more on how and why these large-scale surface zooplankton swarms form.

The Moving Vessel Profiler in less than perfect conditions.

Our cruise started out with beautiful, calm and sunny weather, but during the last two days weather conditions were not that perfect. We were not able to deploy some of our equipment at the stations, due to relatively strong winds and high waves. Nevertheless, we sampled very useful data on water masses and zooplankton with an advanced winch (Moving Vessel Profiler, MVP) that is equipped with instruments contained in a silver body that we call ‘fish’. The MVP takes profiles throughout the water column, while the ship is moving. By tweaking a little bit with the settings of this winch, and thanks to the support of our excellent technicians and the ships’ crew, we were able to run it smoothly even during not so optimal conditions.

Path of the ‘fish’ (blue line) throughout the water column. The winch is set up such that the fish during its profiling always stops 10 m above the bottom (red line) and then returns to the surface.
Hans Dybvik, one of the excellent technicians of the University of Tromsø, in front of the Moving Vessel Profiler.

In addition, two autonomous platforms are surveying the waters around our ship, a Sailbuoy that is equipped with advanced acoustic sensors for zooplankton, and a SeaGlider that amongst other things yields very high resolution of water masses. Those platforms can stay out in all types of weather. All in all, so far the cruise has been very successful. This year, it seems that most of the surface aggregations are located close to the coast.

The SeaGider on deck of R/V Helmer Hanssen, before launching it outside the Vesterålen islands.

On Monday, we will take a short trip to Svolvœr, Lofoten, and take a few pupils, artists and journalists on board for a while to show them a little bit on what we are working with.

Sunset seen from our research vessel Helmer Hanssen.

Wish you all an enjoyable weekend!