A history lesson on Dronning Maud Land

The first person who set his foot on Dronning Maud Land was a Scottsman William Bruce. After that, the Norwegian ship owner Lars Christensen financed 9 expeditions for whaling and sealing with the ships “Odd”, “Norvegia” and “Troshavn”, as well as aircrafts to map the area. The first expedition was under Hjalmar Riiser-Larsen in 1929-30 when the name Dronning Maud Land was first applied. To claim the area as norwegian territory, a norwegian flag was thrown out of an airplane at the western boundary. In 1938-39, the Germans started an expedition led by Alfred Ritscher with the ship “Schwabenland” and two aircrafts that they used to fly over the territory seven times within 17 days, They photographed an area of 350 000 km² and dropped down several Nazi-flags. They wanted to claim the area as theirs.
Luckily, the norwegian Adolf Hoel came for a visit to Berlin, where he found out that his friend had left to an Antarctic expedition. Adding two and two together, he guessed what the Germans planned and notified the Norwegian government. On 14 January 1939 – five days prior German arrival–, king Håkon VII officially annexed Dronning Maud Land as Norwegian territory.

Beautiful phytoplankton – the basis of the marine food web

On the way to our intensive study area in Dronning Maud Land, the work package leaders on RV Kronprins Haakon constantly have to keep the cruise plan updated with the time schedule and with sea ice conditions, weather and whatever interesting is coming up on the way. Looking at satellite images, Sebastien Moreau (NPI) discovered a large phytoplankton bloom, which could provide a vital source of food to the ecosystem at the onset of winter as well as draw down a lot of atmospheric CO2 before sea ice caps the ocean for winter. We therefore changed the route slightly to cross through the bloom to take measurements and water samples.

Strong bloom (orange area) developing west of Droning Maud Land in our research area (SAR image, March 2019).

While inside the bloom, the observers on board spotted more than 100 whales, compared to about 5 on other days. The whales are there for one reason: food! And the food chain starts all the way down with primary producers that are the food for krill. The Antarctic krill has an estimated biomass of around 389 000 000 tonnes, which is more than the global population of humans! More than 50% of this mass fuels the ecosystem: the whales, seals, penguins, squid and fish.

Primary production in the Southern Ocean is generally low despite high nutrient concentrations. This is due to low iron concentrations. It increases close to islands, coasts, sea ice edge and icebergs. In Dronning Maud Land, many processes that increase primary production come together and green sea ice filaments can even be seen on satellite images.

Inside the giant phytoplankton plume, water samples were therefore taken and analysed with microscopy. It is incredible that nature can create those beautiful pieces of art that are so important for the life on earth!

Microscopy of phytoplankton from a giant plume in Dronning Maud Land. Photos: S. Moreau (NPI)

 

Measuring the ocean with autonomous submarines

On Tuesday, we sent two autonomous submarine on their missions in the water (read about their big sister, the Swedish AUV of Anna Wåhlin here: Rand under Thwaites) ! They are seagliders, autonomous underwater vehicles that measure physical ocean properties automatically. Instead of propellers, they use buoyancy and wings to dive down to about 1000 m depths and up again. This means they move up and down in a zick-zack pattern. Once at the surface, they can communicate via satellite to a remote pilot to send the data and the location. The pilot can then change the route or give new commands. A seaglider can dive over several months without running out of battery, and it measures with very high precision. It is impressive, that even though we are in Antarctica, the pilots can control it from the Geophysical Institute in Bergen and even get data immediately each time the glider comes to the surface!

Glider deployment from RV Kronprins Haakon in Dronning Maud Land. Both sea gliders we are are provided from Ilker Fer’s Norglider team at GFI, UiB in Bergen.

Those gliders will now be diving in the water for about 3 weeks. Until then, they have moved further south and we can pick them up again. Hopefully, everything goes well and they don’t hit the sea ice! We already had to change their routes, because of an increased sea ice cover in the areas where we wanted to go. One of them now dives through an area with very high primary production, where we could find a lot of biological activity!

DIY drifters!

Drifters on their way to be deployed

While Nadine is wathing icebergs drift by in the Southern Ocean, I brought the students in GEOF232 back to Masfjorden, a fjord just North of Bergen.  No icebergs to be seen there (luckily), and the only thing we saw drift by was Our own DIY drifters that we had deployed in the fjord!

A drifter is simply an Object that drifts With the Ocean currents and then on a regular basis reports its position back. Now, you can pay a lot and buy a fancy drifter… or you can build Your own (almost as fancy). That’s what Our handy technician Helge Bryhni did! All you need is some paint trays, a bucket, flotation, some rope and chain – and one of these devices that you are supposed to put on your (expensive) car so that you can find it again if it gets stolen. To be on the safe side, Helge opted for a radar reflector and a water proof container.

Video by Algot Peterson, UiB

The students got to decide where and how to deploy our four drifters – spread out or together? in pairs with different depths*? near a river outlet? on rising tides or sinking tides? – and once they were in the water they could sit back and follow the drift on their mobile phone!

*by adjusting the length of the rope we could Place the bulky plastic part of the drifter on the Depth we wanted, and the drifter would then follow (and show us) the water motion at that Depth.

 

 

 

 

 

 

 

 

 

 

Attachments

The daily life on RV Kronprins Haakon during the transit

Finally, we have reached our study area in Dronning Maud Land. Since we left Punta Arenas 10 days ago, we have been sailing non-stop through the Southern Ocean. You may wonder what we have been doing the whole day on board?

First of all, our instruments and gears were piled up in huge containers and had to be unloaded. Labs had to be prepared and packed into plastic to avoid contamination, bottles had to be sorted and all equipment had to be stored securely to not fly around ones we hit high waves. The group leaders used the transit time to plan our tracks in more detail, decide where to take samples and where to do measurements. Some of us already started taking measurements during the transit!

Otherwise the days are quite similar to home when we work on our computers, just that once in a while someone shouts: Iceberg! Whale! Or, watch that beautiful petrel outside! Of course, we also have to take time to clean our own workspace and do the laundry.

Scientists working hard during the transit on Kronprins Haakon. Photo: Anne Helene Tandberg, UiB

Before we went on board, most people didn’t know each other, and now we have to share the cabin with another person. You better hope for someone who is not snoring! However, we already made new friends and spend some time with social activities. On Fridays it’s quiz-night, on Saturdays we play twister, every evening after dinner we do HIIT on the Helideck and we watch movies together, play table tennis, basketball etc…. The work at the stations will work much better if we know each other well!

Workout on the Helideck. The waves make the training extra difficult. Photo: John Olav Vinje
Quiz-evening with all scientists and crew-members! Photo: John Olav Vinje

Now, we have finally deployed a Seaglider (Autonomous Underwater Vehicle) and took the first CTD (Conductivity-temperature-depth) section, which was our first station. You will soon hear more about that and other work on board!

BTW, there is also more about our adventure on the UiB webpage!

International women day

Back to RV Kronprins Haakon, we celebrate the international women today! While Elin is active in Bergen at Women in Science 14.15 @ Realfagsbygget and Anna gets excellent data from AUV Ran under the Thwaites Ice Shelf, we collected all women for a group picture on the Helideck! About 40% of the scientists on board are women, plus 3 women from the crew!

All women on the Helideck on RV Kronprins Haakon for the international women day.
Photo: Rudi Caeyers, UiT

Ran under Thwaites II!

The new Swedish AUV (autonomous underwater vehicle) heroine Ran has returned from her second mission beneath Thwaites ice shelf! Just in time for the international women’s day tomorrow!

An AUV is sent down in the water with a pre-programmed mission, e.g. “dive down to 500 m depth, swim 2 km to the east while measuring salinity and temperature and then come back here so that I can pick you up”, while a “ROV” (Remotedly operated vehicule) is connected to and steered from the mother ship via cables.

The name Ran is borrowed from Nordic mythology, where she is the goddess of the deep sea. According to the legend (and wikipedia), Ran catches seamen in big nets and then keeps them with her at the bottom of the sea. Luckily Ran escaped both the nets and the sea ice that was closing up around her pick up spot…  and made it safely back to the mother ship were Anna Wåhlin and the rest of the AUV-team was waiting. I bet they were nervous!

On her second trip, Ran ventured three kilometers in under Thwaites, and brought back information on the sub-ice shelf hydrography and currents but also water samples that will be analyzed back in the laboratory.

Ran and I have one thing in common – neither she nor I would be where we are today without Anna’s support and stubborness. I’m so happy Your “baby” is successfull, Anna. You’ve worked so hard for this to happen! Congratulations!

You can read more about Ran and the expeditions (in Swedish) here!

 

Ran in the sea ice (Photo: Gothenburg University)
The Swedish AOV-team. Anna Wåhlin is to the left in the first row. Photo: Gothenburg University

 

Beautiful icebergs!

Huge iceberg that we passed on the 3rd of March. Photo: Karoline Viberg

Look at this beautiful iceberg that we passed during our transect to Dronning Maud Land! In Antarctica, icebergs of very different size and shape calve off ice shelves or marine terminating glaciers frequently. Did you know that the largest iceberg  that has ever calved off was 11000 km² big? It is called B15 and broke off the Ross Ice Shelf in 2000. More recently in July 2017, the iceberg A68 with 5800 km² disintegrated from Larsen C in the Antarctic Peninsula. In the Figure below you can see that icebergs from the Antarctic Peninsula drift northward and enter the Antarctic Circumpolar Current –entering our track to Dronning Maud Land.

This plots shows modeled trajectories of icebergs for 1997-2008. Class 5 is the biggest iceberg type and they travel very far! (from Rackow et al., 2017)

Observing icebergs and their drift trajectories on satellites is important to avoid collisions with ships, but scientists also study them because they interact with the surrounding ocean and influence the ecosystem. Surface winds push sea ice towards the iceberg on one side and away from them on the lee side, where a so-called polynya (ice-free area) develops. This has a strong influence on biological productivity and ventilation of the ocean. In addition, iceberg melt increases phytoplankton growth and sea ice growth due to the strengthened stratification. Very big icebergs such as B15 and A68 are studied because they destabilize the grounded ice and accelerate ice loss into the ocean. Why do they break off in the first place, what do they do to the grounded ice? Also, how does the underlying ecosystem react to the sudden income of sunlight after many centuries of darkness? All these questions are important for the Southern Ocean, but very little studied. It is not our aim to study the impact of icebergs, but we still need knowledge about it, because the icebergs have such a big influence on the surrounding water.

Today we passed by B15, which has traveled since 2000 all the way from the Ross Ice Shelf to the Weddell Sea. It has lost big parts of it on the way, but it is still very big. We were waiting outside with our cameras ready to take pictures of it, but unfortunately it was too foggy to see anything. That was too bad…