Top image: Bjørnehiet in Rijpfjorden. The cabin was set up by the Norwegian Polar Institute in 1967 in connection with polar bear research. This picture was taken in August 2007 and shows drift ice from the Polar ocean in the background. In the last few years, there has been very little drift ice in the fjord, which is reflected in the fact that we now find much smaller ice fauna in the fjord. Photo: Geir Johnsen (NTNU and UNIS).
Rijpfjorden is a unique place. On 4 September 1945, the last armed German soldiers in Europe surrendered there. 6000 years ago, blue mussels grew on the shore, and in the 1990s cod was caught in a lake that has since been called the “cod lake” (Torskevatnet). And since 2006 we have used Rijpfjorden as a large and natural climate laboratory.
13 September 2018
Text: Professor Jørgen Berge (UiT The Arctic University of Norway, UNIS and NTNU) and Professor Stig Falk-Petersen (Akvaplan-niva and UiT The Arctic University of Norway).
On this year’s UNIS cruise with the research vessel Helmer Hanssen we had a somewhat sad task – we had to remove the station we established in Rijpfjorden in connection with the International Polar Year. In the first half of August 2006, in collaboration with the Governor of Svalbard, a cabin and equipment were set up which we would use as a base for our research the following year. At the same time, an ocean observatory was also deployed.
Later, in February 2007, the rest of the station was set up in collaboration with the coast guard ship KV Svalbard. From the official opening of the International Polar Year in March 2007, we lived and worked for the rest of the team for extended periods through 2007 and 2008. UNIS researcher Janne Søreide also organized a longer expedition to Rijpfjorden in the winter of 2013. However, while the station has been manned for shorter and longer periods, the ocean observatory has been in continuous operation since 2006. The ocean observatory is still in operation, and will be for at least five more years.
But now it was time to remove the land station. Therefore, there are two somewhat wistful professors who will share some thoughts about what we have learned, both about Rijpfjorden, about the effects of climate change and, not least, the importance of using East Svalbard actively as a climatic laboratory.
Following in Barentsz’ footsteps
Rijpfjorden is named after Jan Cornelisz Rijp, the captain of the second ship in Barentsz’ fleet, who discovered Spitsbergen in 1596. The expedition was aimed at exploring the northern seas. In this way we follow in Barentsz’ footsteps when we have used Rijpfjorden as a laboratory to study Arctic marine ecosystems.
Since we started working in Rijpfjorden in 2006, 15 PhD students have written their dissertation based entirely or partly on data from there, and more than 50 scientific articles have been published. In addition, a number of Master’s degree students have used Rijpfjorden as a study subject, and student courses from both UNIS and UiT have worked annually either in Rijpfjorden or used data from the ocean observatory.
Rijpfjorden has therefore been widely used, and is an important part of the marine research carried out in Svalbard over the last 12 years. In particular, the cooperation with UNIS and all the student courses we have had in Rijpfjorden, have almost given a whole generation of new Arctic marine biologists access and knowledge about this special and very interesting fjord.
The Svalbard fjords are affected by the Gulf Stream. This applies to most of Svalbard, albeit to varying degrees. On the west coast of Spitsbergen this phenomenon is particularly noticeable, where hot (compared to Arctic waters) water flows into the fjord. This hot water not only keeps the fjords on the west coast free of ice, it also brings a whole host of more southern species, such as blue mussels, mackerel, cod, haddock and herring, to name a few.
In Rijpfjorden, on the other hand, we see few signs of this. Admittedly, there is an annual influx in the spring of relatively hot water, but the fjord has an annual ice cover and a winter temperature that has largely remained unchanged since we started the measurements in 2006. An interesting fact of the influx of hot water in Rijpfjorden is that it exclusively happens in the upper 100 meters of the water column.
Atlantic water is saltier and warmer than Arctic water, and thus heavier, which would indicate that it would come into the deeper parts of the water column. We have also done calculations that show that the heat that comes into Rijpfjorden annually is too high to just be the result of solar heating. The heat must therefore come from that Atlantic water masses are mixed with colder Arctic water masses on the shelf area outside Rijpfjorden. The water entering Rijpfjorden is thus modified Atlantic waters that bring a mixture of Arctic and more southern species. For example, there is often a lot of jellyfish in Rijpfjorden, something we more often see on the west coast of Spitsbergen. However, the big picture is that Rijpfjorden has a clear dominance of typical Arctic species – this is the Polar and the marine amphipod Themisto libellula’s kingdom!
In both Kongsfjorden (west coast of Spitsbergen) and Rijpfjorden we operate an ocean observatory that continuously measures temperature, salinity, currents, biological production, day- and night migration of zooplankton, sounds from whales and much more. The observatory in Kongsfjorden has been in operation since 2002 in collaboration with our colleagues in Scotland (SAMS).
The measurements show that Kongsfjorden has been, and still is, in great change. The average temperature in the summer has increased by 0.07°C per year since 2002, while the corresponding increase for winter is 0.16°C. Over a period of 17 years, this is a significant increase, especially in the winter. In Rijpfjorden, however, both summer and winter temperatures have been stable since the measurements started there in 2006. While Rijpfjorden, as opposed to Kongsfjorden, is cooled to the freezing point (-1.8°C for seawater) annually, we begin to see the outlines of a significant change in how long the ice cover lasts.
The variation in ice cover is indeed large between years. However, in the first part of the observation period, there was ice cover in the fjord up to 200 days per year. In the winter 2017/2018 there has only been ice cover in the fjord for around 20 days. This change will, if it continues, be of major importance to the marine system in Rijpfjorden. Already now we see changes: while we previously found a lot of ice fauna (ie. animals that live all or most of their life in the ice) that came drifting into Rijpfjorden with sea ice from the north, now it is a rarity to see such a thing.
This change is probably linked to a reduced ice cover in the Arctic Ocean and the Fram Strait, there is simply more open water around Svalbard today than a few decades ago. A shorter winter will also be of great importance to the production in Rijpfjorden, especially if the ice cover lasts shorter in the spring.
But overall, this makes Rijpfjorden a perfect climate laboratory. Rijpfjorden will continue as a climatic laboratory based on data from the ocean observatory and expeditions with research vessels, but at the closure of the land station, there is at least a temporary stop for the studies of the marine ecosystem during the ice covered time of the year. Nevertheless, we will do our outmost to continue following the ecosystem developments here, as Rijpfjorden still has a lot to teach us about Arctic marine ecosystems!