Polar Glider team is growing!

Welcome Dr Marcel du Plessis to the Polar Glider group!

Position: Postdoctoral Research Fellow

Contact: marcel.du.plessis@gu.se

Marcel will be working from the GU Marine Science Department at Carl Skottsbergs gata 22B, Gothenburg

Brief Bio: Dr Marcel du Plessis joined the Polar Gliders Group at GU in March 2020 as a SO-CHIC (Southern Ocean Carbon and Heat Impact on Climate) Postdoctoral Fellow. Previously, Marcel was a Postdoctoral Fellow at the Southern Ocean Carbon and Climate Observatory at the CSIR in South Africa and before that completed his PhD and BSc at the University of Cape Town. His doctoral research focused on using both glider observations in the Subantarctic Zone and numerical models to better understand the processes driving mixed layer variability at intra-seasonal time scales. Throughout his PhD and postdoc, Marcel has worked closely with the Polar Glider Group, with 6 visits to GU over the previous 4 years!

Dr du Plessis has joined the SO-CHIC project to work on WP1, where he will utilise autonomous surface vehicles, ships, and gliders to estimate high-resolution air-sea fluxes and upper ocean mixing processes with a focus in the Weddell Gyre, a region strongly linked to upwelling and CO2 outgassing. He hopes his research outcomes will have a positive impact on the scientific community, providing insight about time and space scales of upper ocean variability which are vital for modelling parameterisations that guide future climate modelling efforts. These efforts will support major international scientific assessments of the climate state, such as the IPCC.

Polar Gliders gets new SeaExplorer Training

Four new Autonomous Underwater Vehicles called SeaExplorers have arrived in Gothenburg. They are buoyancy propelled gliders developed by the France based Alseamar-Alcen that yo up and down in the ocean collecting physical and biological measurements. These gliders were brought to Gothenburg by Ola Oskarsson through an initiative called Voice of the Ocean (VOTO; http://voiceoftheocean.org/) and will be used for an oceanographic long-term project to measure oxygenation and the physical ocean dynamics of the Baltic Sea and Skagerak-Kattegatt.

Marcel, Nicolas and Andrew retrieving one of the two SeaExplorer’s deployed overnight on Wednesday! Photo: Seb Swart

Two Polar Gliders members, Seb Swart and Louise Biddle, along with Bastien Queste, a Lecturer in Marine Science at GU, are working closely with VOTO to help set up their glider infrastructure and sampling strategies. The project aims to kick off after the 2020 Swedish summer, but before that can happen, an intense week of SeaExplorer training was had. Estel Font and Marcel du Plessis from the Polar Gliders group joined Seb and Louise at Nya Varvet for the training week. 

The training was run by Nicolas Buisson from Alseamar. Monday was an intense day of theory, while Tuesday we managed to get outside and prep the gliders for their first deployment. Wednesday was the big day when two of the four gliders were deployed in the Kattegat. There was a good mix of nerves and excitement around, and to make things even more interesting, the gliders had to dive across 14 sigma units of density, almost double the units of the SeaExplorer’s “extreme case” scenario!

Seb and Johan inspecting the buoyancy of SEA044. Photo: Marcel du Plessis

After a slight readjustment of the deployment location due to some trawler boats hanging around, the gliders were put in the water at lunchtime, which made for some interesting remote cafeteria piloting. As Nicolas was on the boat, this left Louise, Seb and Marcel, who stayed behind with two others from MMT, as land pilots to navigate the piloting software (albeit with a remote Alseamar pilot looking over our shoulders). Wednesday piloting was a success and we managed to eventually get the gliders to dive across the strong freshwater stratification! 

Thursday morning was recovery day. Marcel and Seb joined the boat team to go pick up the gliders and beautiful conditions meant that spotting them was easy. Upon collecting the first glider (SEA056), we noticed streaks of black paint and two big dents! A big warning that navigating these waters is going to be a challenge for the VOTO pilots! Nonetheless, we had both gliders on board in no time and with the lovely Swedish sunshine, we stopped off for a lunchtime swim in calm 19°C water.

Participants of the SeaExplorer Training course! Photo: Seb Swart

On Friday we consolidated the deployment, went through some case studies for future missions, performed compass calibrations and began work on the other two gliders. The SeaExplorers undoubtedly passed the test (with a few hiccups) and look like they will be a great instrument to monitor the Swedish waters. Overall, it was a fantastic week of training and a huge thanks to VOTO (Ola Oskarsson and Olle Petersson) for the opportunity to learn about a new instrument and to Alseamar for the training course!

Beautiful warm conditions upon retrieval! Photo: Marcel du Plessis

Written by: Marcel du Plessis, Seb Swart & Louise Biddle.

Penguin bukta!

Just in time for Christmas, we arrived in penguin bukta. Actually, this is more the save parking spot for the boat at night, when no offloading or fuel-pumping is taking place. But it is at the same time also a wonderful spot for observation of penguins, whales and seals. To celebrate the first Christmas day, we took a walk on the ice. The penguins were very curious about us, so we were able to take some gorgeous photos of the penguins in front of the massive ice bergs!

In the meantime, we were busy in the lab to fix the underway PCO2 measurement system. Since the start of the journey, we had some bad luck about it and disassembled and replaced its pump and peltier element and fiddled with its software. It seems like it is cursed and it just would not start to work. But eventually we will get there. We still have some time left here in Penguin Bukta until we fly to the fast-land base on the first of January…

Deployment 60°S!

On this cruise, we had the mission to deploy two wave gliders and our brand new Sailbuoy as far as 60°S. In this region, the ice melts only for a few month in summer. Our ocean gliders where stored in stable plastic containers during the first weeks of the cruise, to protect them from rough weathers, swell and unattentive researchers or crew.

Only on the afternoon before deployment, we unpacked the gliders and mounted the wings on them. Then they also had to go out on outer deck for some final function testing. By now the gliders and a Sailbuoy are in the water, sending their updated measurement data to us every day. They will be measuring on their own for the next couple of month, sending us the measurement data via satellite connection. You can follow the incoming data close to real time on our web page http://www.roammiz.com!


Deployment 54°S!

The weather is playing games with us lately. As early as six o clock in the morning we were expected to reach the deployment site for our oceanographic measurement instruments. In the evening before deployment when we tried to get ready and prepared, the wind and the ocean swell picked up. We were getting wet, seawater sprayed all over us on the outer deck, but we also feared our and the measurement instruments safety with the waves roling over the lower deck. But the deployment of our measurement instruments into the southern ocean are what we came here for, and the preparations took us long. So we did our best to strap our measurement instruments in place on the outer deck for some final tests and adjustments.

After the straining day with much time on the outer deck, we were so happy to finally come inside and go to sleep in the evening. The last thing to do was to plug one of the wave gliders into the power supply for charging. But what was that? When we plugged it in for final recharging of the batteries, the battery was rather draining then filling up! The whole measurement mission was in danger, the gliders stay in the ocean for many month at a time and we can not release them only partially charged! So we started digging into the software and plugging/unplugging cables until finally, long after midnight with only a few hours left before deployment we got it working! The charging signal came on and we prayed that the night would be enough to get some substantial charge into the batteries.

The next day early morning after just a short sleep, we were approaching the station for deployment. The Agulhas II is a big vessel on a supply cruise for the antarctic base. As a small group of scientists, we are expected to get the deployment done quickly and not make the ship waiting to long for us. We hoped the deployment could be done in about two hours. Two gliders are configured on deck, picking up satellite communication, receiving answers from the pilots at hour home universities. Then we are watching the instruments going into the water while also coordinating a calibrating CTD cast and taking underway sampling. There is just so much that is supposed to be happening in a very short time, and it requires precise preparation.

Science expedition Antarktica!

On Friday morning, we left the harbor. With the South African ice breaker SA Agulhas II, I am on my way from Cape Town southwards. We are following the Greenwich meridian. Currently, we are between 30°S and 40°S, it is summer on the southern half of the globe and I enjoy the light and the warmth after the Swedish winter darkness. The ship is loaded with antarctic supplies for the base station. Snow cats, fresh food, and new technology that makes the life on this remote place possible for the scientist and engineers. The southern ocean is the roughest and most dangerous ocean. Everything has been fairly calm yet, we are traveling through the long slow swell, that is making the ship going up and down slowly. Half of us scientist is sea sick anyway, but that will get better over time. We brought our measurement instruments also, tomorrow we will reach our first deployment station. More about that later.

We almost reached the 0-meridian. Then we will only continue southwards. First we are going to cross the “roaring forties” only to proceed into the “screaming fifties”. After that the sea should calm down again. In the moment, it is summer on the southern side of the earth, but we expect to get into sea ice at around 60°S. From there, it will be few more hundred kilometers to the antarctic continent. In winter, the Weddell Sea is covered by thick sea ice but now in summer we can make our way through. The SA Agulhas II is one of the worlds biggest advanced ice breakers, and with the help of current satellite images and our experienced captain Knowledge we will arrive eventually the ice shelf to supply for the South African Antarctic base station.
On Christmas eve, we will already be in Antarctica. That is going to be a weird Christmas, with 24 hours of daylight, but white Christmas is almost guaranteed for the first time! The whole journey is going to take three and a half month for me. So long, it has been quite hectical. Some of hour scientific instruments were misbehaving in the very last hours of preparation, but as soon as we are coming closer to Antarctica it will get calmer for us oceanographers. Then I can finally spend more time with admiring the awesome nature, taking photos and enjoying the environment. I hope we will meet some curious penguins along the way!


SEAmester – South Africa’s class afloat!

IMG-20180716-WA0001SEAmester is a South African initiative to take students and scientists to the sea. The scientists are sampling the water in front of the south African coast along the ASCA array, to gain more knowledge about the Agulhas current. At the same time, we students have the opportunity to learn right where the science happens! Spotting birds and mammals, taking water samples, doing CTD casts, the program is just as diverse and colorful as the participants.

This year, Isabelle and me have the chance to be on board during the 11 days trip. Having never been to Africa before, for me the adventure began even earlier. Making all the way from the University of Gothenburg (SE) to Cape Town (SA), it was a long journey and luckily I had a couple of days before to discover the beauties of Cape Town. And what a great town it is! Close to the southern end of Africa, it is very exposed to the weather and the climate is influenced by the two ocean currents on either side.
The table mountains and Cape point are two of the places to go in Cape town, and the long powerful waves are a reminder how exposed Cape town lies to the open ocean.

The currents here, especially the Agulhas current are very strong. With a velocity of up to 10 km/h, it is way faster than people can swim. And it is a nice warm ocean current, making the evening on deck cozy even after sunset. The wind and swell, even though being gentle with us, made some of our friends onboard turn green and sick. 😦

I feels good to get some hands on experience with different sampling methods. Even though most sampling methods are fairly easy, I is good to know (as an oceanographer) how a Niskin sampling-bottle works, and not having to learn it when a team of scientist are actually relying on the data and that bit of water that is sampled in the depth using a CTD rosette.

The sea-life here in front of South Africa is amazing! Today we spotted seals, Humpback whales, and a whole lot of different birds already! The scientists, watching the marine mammals, working for the south African weather service or researching the currents are also giving lectures and sharing their knowledge – about the ships weather station and measurements, balloon starts and simple forecast strategies.

During the SEAmester programme, we are also recording a short video clip of the experience. It will be linked here once it goes public, so stay tuned!

Davos, Switzerland – the highest town in Europe, sitting at an altitude of ~1800m, saw the meeting of researchers with a focus on all things arctic, antarctic and the high altitude at Polar2018. The #polarglider team had a busy week, which kicked off with a trail run to 2700m: setting the scene for clear minds and new perspectives on polar science.

A successful SOFLUX (Southern Ocean Fluxes) meeting was facilitated by Dr. Sebastiaan Swart, show-casing the Southern Ocean Observing System tools available of their website,  which encourages collaboration, and highlighting the absolute sparsity of observations in the Southern Ocean – especially during winter.


Dr. Sebastiaan Swart presents on the Southern Ocean Observing System as the COMNAP session during Polar2018

Amidst the 25 000 croissants that were served throughout the week at Polar2018, Dr. Louise Biddle updated the scientific community on the ability of satellite-tagged seals to measure submesoscale processes and Marcel du Plessis presented a poster of his recent work on the role of wind driven submesoscale processes in delaying the onset of restratification after winter in the Sub-Antarctic Zone.


Dr. Louise Biddle presenting progress in the analysis of submesoscales in the Marginal Ice Zone using seal tag data

I attended the Polar2018 meeting as a PhD student at the beginning of my journey in the field of physical polar oceanography. It was inspiring to get first hand exposure to the latest progress, discoveries and plans of the global polar oceanography community. Some exciting technology was presented. Particularly

With new advances in technology, previously inaccessible polar regions are getting closer to the reach of the human mind and our scientific understanding is accelerating as demonstrated during the Polar2018 meeting – ever more important in an era of uncertain climate change.