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 areseagliders, 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!
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!
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.
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!
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!
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.
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…
After a delayed departure, we are rapidly heading towards the Drake Passage and into the Antarctic Circumpolar Current to reach our measurement area. The captain is giving his best and keeps a velocity of 9-10kn (instead of the 8kn that we expected). Maybe we’ll catch up! You can follow our track at http://havstraum.no/dml where you can also see our stations and satellite images.
Until we are at the first station, people are preparing their labs and observations are going on. The observers have the best spot on the ship and get a lot of company up there. We have already seen a lot of birds, whales, dolphins, penguins etc!
Finally the ship has arrived and we could check in to our cabins! It is beautiful with big windows, meeting rooms, many labs, gym, sauna, hottop, great views and so far a lot of containers with instruments standing around. We are still sorting out all the equipment and getting it in place. The plan is to leave today after lunch (we are 4h behind Norwegian time), so cross the fingers we’ll manage. So far we are already one day delayed because the ship had to leave to pier the whole day on monday, but the mood is good and everyone is amazed by how efficient the crew is working. Let’s hope we can leave soon!
Yesterday after arriving in Punta Arenas, I took Maudy with me to check out the ocean and to look for RV Kronprins Haakon. It was nice to get some fresh air after a 28h travel, but we couldn’t spot the ship yet. We’ll have to wait a bit longer, so in the meanwhile I will go kayaking. See you soon!
… obviously because we want to gain more scientific knowledge about the ocean in Dronning Maud Land – both about the biodiversity (fish, mammals, plankton, benthos) and the physical aspects (water masses, currents, sea ice).
However, there is also a political reason behind it. Antarctica is nobodies land and divided into territories from different nations. To avoid exploitation of the land and the Southern Ocean, an Antarctic Treaty was signed in 1959 by the 12 nations that were scientifically active. Today, it consists of 53 parties. Within the Antarctic Treaty, there is a Convention on the Conservation of Antarctic Marine Living Resources, that started in 2008 to regulate fisheries in Antarctica and to adopt Marine Protected Areas (MPA). It is part of the global objective of UN Convention on Biological Diversity to protect 10% of coastal & marine areas by 2020.
The biggest MPA today is in the Ross Sea in Antarctica. Further MPAs are under development, but are not consensus yet. One of the discussed MPAs is in the Weddell Sea and partly contains Dronning Maud Land, under Norwegian claim. A science-based management is crucial for the planning of the extent and conditions of the MPA, which is the reason for why we are going there with people from different scientific backgrounds.
Only a few days left until I am taking off to Punta Arenas in Chile from where I will take you on a new science adventure. Me– that’s Nadine, Elin’s PhD student, I will be on the ocean for seven weeks and explore Dronning Maud Land, the Norwegian territory in Antarctica, together with scientists from different marine science disciplines. The area is far away from any civilization and the transit from Punta Arenas takes about 11 days. At the moment, I am arranging the last details for the travel and the suitcase is slowly filling up. What’s in there? A warm working suit, safety shoes, gloves, hand warmers, sea sickness medicine, chocolate, an ebook reader stuffed with books, movies, a camera, my computer and most important, Maudy my mascot! The instruments that we’ll use are already sent down, among them a mooring (long chain of instruments) that will be anchored at the ocean floor in front of Fimbul ice shelf. In two years, we will hopefully be able to get back there to pick up the instruments full of data that tell us what influences ice shelf melt, ocean currents, changes in water masses with time and much more. The other scientists on board will be looking at sea ice, mammals, fish, benthos, zooplankton and micronekton. What this all is? To be honest, I am not so sure myself, but I have a lot of time to find out and I will keep you posted. You can follow my stories about the area, the measurements, the life on board here or on twitter (@DareliusElin) and facebook (EDarelius&Team) during the next weeks. Hopefully there will be some nice pictures of penguins and ice bergs!
Maybe you remember the blog posts I wrote a year ago about the cruise to the Amundsen Sea onboard the South Korean icebreaker Araon? (If not, see here!) Maybe you have even been wondering what we have been doing with all the data we recovered? About two weeks ago we had our first paper using these data published in a journal called Geophysical Research Letters: Warm Circumpolar Deep Water at the Western Getz Ice Shelf Front, Antarctica
Our two years of data show that there is a constant flow of warm water towards the western Getz Ice shelf and that this flow is pretty fast (20 cm/s). The distance from the shelf break, where the warm water comes from, to the ice shelf front is just 110 km so it takes only about a week to get from the deep ocean basin to the ice shelf front and the water does not have time to cool down much along its way. Temperatures in the inflow reach up to 1.59°C at the ice shelf front which makes this water the warmest that has been observed at any ice shelf front in the Amundsen Sea. The water reaching the Getz ice shelf cavity is hence warmer than the water reaching the fast melting Pine Island and Thwaites Ice Shelves further east!
To investigate what drives changes in the temperature and thickness of the warm bottom layer, we compared our ocean observations to wind data from the area and found that stronger easterly winds in the area make it harder for the warm water to reach the ice shelf front, because they depress the warm bottom layer over the shelf break. Climate projections indicate that these easterlies will weaken in future, making it easier for the warm water to get to the ice shelf base. We also find that gradients in the wind field over the shelf break control the thickness of the warm layer on longer time scales. This is a mechanism that previous studies have used to link changes in the wind field to changes in ice shelf flow velocities and melt rates, but these studies have lacked oceanic observations to support their hypothesis. Our observations close that gap and prove that the ocean does indeed react in the way that these studies imply
There is more science using these and the other mooring at the western Getz Ice Shelf moorings in the pipeline, so watch this space!