Impact of melting glaciers on Greenland fjords

The Belgica Documents Climate Change in an Arctic Marine Ecosystem

On the 13th of July 2023 the new Belgian oceanographic research vessel RV Belgica is leaving from Reykjavik, Iceland, for a trip of three weeks to southwest Greenland. The international research team on board will make use of the advanced facilities on board of the ship to investigate how climate change, and more specifically changes in glacial melt, will affect the carbon dynamics, biological communities and food webs in Greenlandic fjords, a typical Arctic marine ecosystem.

Fjords are systems of regional and global importance by supporting highly productive and diverse food webs. As this rich marine life stores a lot of carbon, the fjords play a far more important role as CO2 sinks than one would suspect based on their limited size relative to the vast ocean basin.

From Marine- to Land-terminating Glaciers

These days, global warming significantly impacts fjord systems through the accelerated melting of ice, with the greatest impact in polar areas such as Greenland. Here, coastal glaciers often terminate in the fjord, so called marine-terminating glaciers.

However, especially at Greenland’s marine-terminating glaciers draining 88 % of the ice sheet in the study area, discharge has recently increased sharply caused by increased melting of the ice sheet. As a consequence, many of Greenland’s marine-terminating glaciers are gradually shifting to land-terminating glaciers, a process which will likely intensify in the near future.

Floating icebergs in a Greenlandic fjord originating from a marine-terminating glacier. (©UGent/A. Vanreusel)

Impact on Ecosystem Functioning and Services

Whereas there is increasing evidence that shifts in glacier types cause major changes in the physical, biogeochemical and ecological processes in the associated fjord systems, the consequences for the marine food web and carbon burial in sediments are currently not fully understood. As a result, the impacts of further warming on ecosystem services provided by Arctic fjords (e.g. food provisioning, climate regulation) remain unknown.

This Belgica expedition aims to investigate to what extent changing glacial melts in Arctic fjords may lead to lower primary productivity and a less rich food web. The research is part of the CANOE project (Climate chANge impacts on carbon cycling and fOod wEbs in Arctic Fjords), which is funded by the Federal Science Policy Office (BELSPO).

Study Area

The study area consists of two adjacent fjords with contrasting glacier input, respectively marine- and land-terminating. In both fjords, a gradient from shelf to inner fjord will be sampled. Oceanography and pelagic (water column) biogeochemistry will be described at high resolution in each fjord (oceanographic stations), in addition to the benthic (seafloor) biogeochemistry and biodiversity (basic and medium stations), while the food web will be described and quantified at two contrasting locations in each fjord (full stations).

Research area in South Greenland, with indication of the planned sampling locations and bathymetry. Ikersuaq fjord is influenced by marine-terminating glaciers, while Igaliku fjord is influenced by a land-terminating glacier. (© CANOE)

“With this expedition the team will contribute to major societal concerns for which research-based management strategies are crucial for the future” says Ann Vanreusel, professor at the Department of Biology of Ghent University and chief scientist of the RV Belgica Greenland expedition. “By providing insights into expected climate change effects on coastal marine food webs, important information for a future ecosystem-based management in the Arctic fjords is generated.”

The CANOE project, coordinated by prof. Ulrike Braeckman (RBINS and UGent), will also construct predictive models that will help to anticipate the ongoing and future climate-related shifts in marine ecosystems and the consequences for natural resources and other ecosystem functions such as CO2 mitigation.

The Tradition of Integrated Research

Belgium has a long tradition in marine Arctic research since Adrien de Gerlache set sail with the historical Belgica in 1907 for a scientific expedition exploring parts of the Arctic Ocean. Even at that time, this involved integrating many research disciplines into the expedition, and involving scientists of different nationalities. In the spirit of this tradition, the CANOE-scientists now also use the new RV Belgica for an integrated and international research campaign, linking physical, biogeochemical and biological aspects of the water column with seafloor processes in Greenlandic fjord ecosystems with glacier dynamics under influence of climate change. Such an interdisciplinary campaign requires optimal use of the numerous oceanographic and biological research instruments offered by the RV Belgica.


The multidisciplinary international CANOE team is led by researchers from Ghent University (UGent) (Prof. Ulrike Braeckman) and also consists of researchers from the Royal Belgian Institute of Natural sciences (RBINS), Flanders Marine Institute (VLIZ), University of Antwerp (UAntwerp), Royal Netherlands Institute for Sea Research (NIOZ), University of Southern Denmark (SDU) and University of Bonn (Germany). The research is also carried out in association with Greenland research institutes.

CANOE is funded by the Belgian Science Policy Office (BELSPO) as beneficiary of a specific call that was designed to give an impulsion to the start-up of research on the new RV Belgica and to allow researchers to get to know the ship and her potential. The project runs from 15 December 2021 to 15 March 2026. For more information of the project please visit

The CANOE expedition with RV Belgica follows the DEHEAT expedition that operated in Icelandic waters from 26 June to 11 July. Here, it investigated how the natural weathering of silicate minerals in the sea consumes the greenhouse gas carbon dioxide from the atmosphere, thereby helping to remove it from the atmosphere, and when accelerated could be an ally in the fight against global warming.

More information on RV Belgica can be consulted at the ship’s websites at RBINS (including live position information and webcam images) and BELSPO. The ship and its scientific activities can also be followed on Facebook and Twitter.

DEHEAT 2023/05 – Hvalfjördur – Five ways to sample mud (2)

28 June 2023 – Three down, two to go! As if the Van Veen grab, the box corer and the GEMAX corer don’t provide the DEHEAT-team with enough sediment samples to learn to understand the bottom of Hvalfjördur and the biogeochemical processes taking place in it, the scientists are sending two additional types of devices to the bottom to collect even more sediments.

The first is the long gravity corer, that essentially consists of a narrow corer of 3m in which a sampling tube is fitted – or two such corers and tubes combined, totaling 6m – and a huge weight to drive the corer into the seafloor (hence ‘gravity’ corer). This way, much deeper sediment layers are cut than with the other techniques, with deeper meaning older. The long cores allow the sedimentological history of the seabed to be reconstructed and to unravel a host of secrets from the past. In the case of DEHEAT and of the biogeochemists on board, this is obviously done with attention to how silicate weathering has evolved over time here, and how historical changes can be linked to climate-relevant processes.

A 6m long gravity core arrives safely back on deck after a successful sampling event.

Christian März, Professor for General Geology at the University of Bonn, is especially interested in the deeper part of the sediments, and therefore depends on the long cores. By studying these, he can determine how the composition of the sediment changed over time and how these changes affected the cycling of essential elements like carbon, metals and nutrients in the seafloor. By studying past environments from the sedimentary records, climate change signals can also be extracted.

“It is also exciting to dive deeper into the topic of silicate weathering, a new and quite hip topic due to the need to stop and reverse global warming. Through this link, my colleague Katrin Wagner and I got offered the opportunity to join the expedition with RV Belgica in Iceland as collaboration partners of the DEHEAT project. As such, we bring in our expertise both for the benefit of our and the DEHEAT research” Christian explains.

However, deploying and retrieving the long gravity corer is anything but an easy task. And once in the water, the actual sampling of the bottom does not prove to be easy either. Indeed, the multi-purpose and interdisciplinary RV Belgica is not perfectly equipped for this particular type of sampling. It takes a lot of inventiveness and advancing insight to get the procedure right, but the highly motivated crew succeeds and regularly delivers usable ‘long cores’ to the scientists.

An elated Christian after several attempts to get a good long core.

Christian: “The long gravity corer cannot be deployed over the sides of RV Belgica, so this has to be done from the stern. If swell causes the amplitude of the movement of the stern to be bigger than the accuracy with which the position of the corer in relation to the depth of the seabed is known, it is nearly impossible to successfully apply this method. We sometimes have to try several times but in the end manage to secure good cores thanks to the crew”. He adds laughingly: “This is why I like working in the central arctic so much. There, the ice prevents the ship from moving and allows us to work more accurately”.

Finally, there is a fifth way by which sediment is brought to the surface during the DEHEAT cruise: the benthic lander. However, it would be irreverent to wear this unit down as a simple ground grabber. After all, the lander does much more than that. It is a platform that is sent down in the deep to take measurements on the seafloor itself, and that is equipped with so-called ‘benthic flux chambers’ that measure the flow of substances between the seafloor and the water above it. It stays on the seafloor for one or several days while the DEHEAT-scientists proceed and sample at another station, and carries out the pre-programmed actions while storing the resulting data in a battery-driven data logger.

The benthic lander that is used during the DEHEAT-expedition belongs to the University of Gothenburg,  Sweden, that employs a true benthic lander guru in the form of Mikhael Kononets. It is almost inconceivable that the lander would be deployed without Mikhael being present to oversee the operation, so the Royal Belgian Institute of Natural Sciences arranged a contract for him for the duration of the RV Belgica adventure in Iceland, as well as for the subsequent expedition in Greenland. He boarded in Galway, Ireland, and was continuously engaged with the lander throughout the transit to Iceland as well as during the two-day stay in Reykjavik. Mikhael and the lander seem intertwined, and he did not even set foot on Icelandic soil but kept busy with making sure that the lander is fully ready for its duties on the RV Belgica. “It’s only concrete, that’s the same everywhere, isn’t it?” he jests.

Retrieval of the benthic lander.

There is some work involved in deploying the lander from RV Belgica, and especially in retrieving it. Mikhael explains how this works: “Deploying the lander is not so much the problem. It can be lifted over the side, after which ballast causes it to sink to the seabed. Old pieces of railway track, which were donated to us by the Swedish company Stena Recycling, are used as ballast in this case. After the lander has done its job, we activate the decoupling mechanism with an acoustic signal via a hydrophone, whereupon the styrofoam-filled compartments cause it to rise back to the surface. The railway tracks remain behind, which is not a problem as primary production in the sea is limited by the availability of iron”.

Only then does the hardest work begin, getting the lander back on board. Mikhael: “First, the floating lander must be spotted. We usually know its position very accurately, but if we cannot see it immediately – due to wave action, for example – we can still determine in which direction to look using a simple radio signal. Once found, the lander is then carefully towed by RHIB (rigid-hulled inflatable boat) to near the stern of the RV Belgica, from where he can then be hoisted on board. The time elapsing during the calling and ascent of the lander through the water column can sometimes be nerve-wracking … after all, there are known cases of landers lost for eternity …”.

Mikhael working on the benthic lander.

For launching this wide variety of sampling equipment, for the actual sampling of the water column and the bottom, and for retrieving the equipment again, it is obviously very important that the platform on which these operations take place is very stable and remains very accurate on site. For the first, the RV Belgica is indeed a very stable vessel but wind and wave action are also important and one also depends on the swell. For the second, the so-called Dynamic positioning system comes into play. Dynamic positioning is a computer-controlled system to automatically maintain a vessel’s position and heading by using its own propellers and thrusters. The DEHEAT-team is blessed: all sampling is proceeding as planned in Hvalfjördur thanks to favourable conditions and the RV Belgica’s Dynamic Positioning. Fingers crossed that this will continue to be the case later on the continental shelf.

Now, don’t get us wrong, the soil sampling techniques mentioned are not only used on the day they are described in this blog but are part of the routine of every day. The same goes for the CTD reviewed earlier, and for many of the operations and analyses that will follow.

And the fjord? It remains its picturesque self!

Beautiful Hvalfjördur.

DEHEAT 2023/04 – Hvalfjördur – Five ways to sample mud (1)

27 June 2023 – How many ways can one think of to bring mud from the seabed to the surface? As many as five are applied during the DEHEAT campaign with RV Belgica, all designed in different ways but with one common goal: bringing samples of the precious mud, its inhabitants and chemical gradients, to the scientists without them having to get wet! However, avoiding them getting dirty cannot be guaranteed! Admittedly, it is better to speak of ‘sediment’ instead of mud, because technically it is not always mud that is brought to the surface. Just as one water was not the other, neither is one sediment the other.

Let’s start with the simplest low-tech method, which is usually the first sediment sampler deployed on any new sampling station during the DEHEAT campaign: the Van Veen grab (or simply the Van Veen). Once the CTD is back on board, that is. This tool is nothing more than a clamshell bucket made of stainless steel that is spread open like scissors while it is let down through the water column. The locking mechanism is released when it touches the sea bottom, making the bucket halves close and grab a sediment sample when the device is pulled back upwards.

Van Veen grab

In the extended sampling scheme, a box corer is usually sent towards the seafloor when the Van Veen grabbing has been completed. This can be done once or multiple times, depending on the sampling needs. From a technical perspective, the box corer is also a rather simple sediment coring device, essentially consisting of a cylindrical core that relies on a weight to aid the cylinder to penetrate into the bottom and on a spade that seals the core from below to prevent the sample from being lost when the unit is lifted back to the surface.

Box corer

Next on the programme comes deploying the GEMAX corer. This one looks a bit like a double torpedo with wings (see photo, showing the device before it is lowered to the seafloor) where tubular sampling containers are inserted into the two cores to be taken out – hopefully filled with sediment – after retrieval.

GEMAX corer

Unlike the Van Veen grab and the box corer, the GEMAX is not deployed just once or a couple of times at every sampling station, but up to 22 cores are collected per location.

Per Hall, marine biogeochemist and emeritus professor at the University of Gothenburg, explains: “The GEMAX takes more undisturbed cores and therefore delivers a more representative sediment sample than for example the box corer. The latter disturbs the sediment more, for several reasons. One is that it has a very big ‘bow wave’ which may blow away particles from the sediment surface. Also, the sediment within the box may be more disturbed, there may be cracks in it, there may be water coming between the box wall and the sediment. That is often fine, like if you’re going for fauna samples, but if you want undisturbed chemical gradients in your cores as is needed for many of the DEHEAT biogeochemical analyses, the GEMAX is a far better choice. So, the choice of corer all depends on the purpose of your sampling.”

Per is a senior academic who is not averse to dirty hands. “Although I am officially retired, I still do part-time research because I remain interested in it and excited about it. Today, I am participating in this expedition on invitation of Sebastiaan, where I try to bring my expertise in throughout the entire chain from the practical aspects of the sampling to the discussions on the data“.

Per with a sample container from the GEMAX corer.

Saheed Puthan Purayil of the Royal Belgian Institute of Natural Sciences helps Per with the different sediment corers. He is a PhD in physical oceanography, and has extensive experience in ocean research, forecasting and modelling. But rolling up his sleeves was less of a part of these experiences.

Saheed hosing down the GEMAX corer in between sampling sessions.

“I have been a part of many scientific expeditions at sea, and in some cases I had the position of chief scientist, but it is the first time that I am actually helping with taking sediment cores. I find it extraordinary to see how the cores are processed after we hand them over to other scientists, and how some data are already appearing during the expedition” he says.

Saheed clearly enjoys being part of the DEHEAT expedition: “It’s also a fun and engaging expedition, with scientists of so many different fields of expertise, institutes and nationalities, and a wonderful ship and crew. And everybody is very friendly!”

All the abovementioned sediment corers, as well as the CTD, are deployed over the starboard side of RV Belgica, using a crane and winch specially installed for deploying such instruments.

The CTD actually has it’s own hangar and deployment system, as you don’t want the sediments flying around contaminating the valuable water samples. Just kidding! Of course, the sediments are also handled with great care. But when hosing down the corers between sampling sessions (as even residual sediments from one sampling must not affect the next) it is not inconceivable that some sediment could get onto the CTD-rosette or into the water samples. And for the scientists carrying out the accurate and clean CTD sampling, it is also more correct and pleasant work in bad weather conditions.

Talking about the weather, we were warned that the weather in Iceland can take any form in summer too. Today we witnessed that, with alternating sunshine, clouds, fog, a gust of rain and even a flake of snow. But Hvalfjördur remained as dramatically beautiful in all these conditions!

It is a pleasure to work in the fantastic scenery of the Hvalfjördur.

DEHEAT 2023/03 – Hvalfjördur – In search of water

26 June 2023 – There is pleasant excitement on the RV Belgica this morning, as the ship leaves Reykjavik harbour and steams to the first sampling station. No far journey ahead, as the first days of the expedition will be spent in a fjord just north of the Icelandic capital. The fjord in question is the Hvalfjördur, literally translated as the ‘whale fjord’. It only takes less than two hours to arrive at station HF3, which gets the scoop of being the first to be sampled. That first sampling is always a crucial moment, as it is definitely better for morale to start with a success. However, only one thing is certain at this point: the weather will certainly not be a killjoy! The water is calm, the wind absent, and there is pleasant sunshine.

RV Belgica sails into Hvalfjördur.

The DEHEAT campaign kicks off with a CTD deployment, which will become the regular start of activities at each sampling site. CTD stands for conductivity, temperature and depth, parameters that are measured by sensors that are incorporated in a construction that further includes 24 so-called Niskin bottles arranged in a rosette. For simplicity, we refer to the whole thing simply as ‘CTD’.

The rosette with 24 Niskin-bottles and CTD-sensors leaves the dedicated CTD-hangar of RV Belgica.

The CTD-construction is an essential oceanography instrument. As the CTD descends through the water column to just above the bottom, the depth and the changes in temperature, salinity and oxygen content of the water can be monitored in real time on a computer screen. Depending on the course of these parameters, the scientists will decide at which depths water samples will be taken. That is where the Niskin bottles come in, as they can be closed remotely one by one with a simple mouse click. This is done during the rosette’s journey back to the surface.

Real-time monitoring of temperature, salinity and oxygen content to determine at what depths the various Niskin bottles will be closed.

During the first trip of the CTD to the bottom and back up, the wet lab where the computer on which the CTD parameters are monitored was particularly crowded. Everyone wanted to personally witness the very first data that appeared during the DEHEAT expedition. In the following days, this moment will be much less attended. Of course, this has nothing to do with a loss of interest but is entirely due to the fact that during the very first CTD, no other activities had yet started. Things will be very different at subsequent stations, and the timing of activity from different scientists will also be increasingly divergent as a result.

A very busy wet lab during the first CTD measurements.

Later, it will therefore mainly be some regular faces who will be present at every CTD, make the decisions on water sampling and close the Niskin bottles. Besides DEHEAT chief scientist Sebastiaan van de Velde, the permanent CTD team consists of Kate, Lei and Felipe. It is also they who will eventually sample the contents of the Niskin bottles in different ways for different purposes.

A decent administration is involved as everyone on board wants their share of the water, and one water turns out not to be the other … There is a need to collect samples for determining alkalinity, dissolved inorganic carbon, nutrients, Silicium, metals, oxygen, Magnesium & Strontium, salinity, … and all of these samples are needed in different volumes, need to be stored in different recipients, require different processing and need to be brought to different places on the ship. To complicate matters further, some samples have to be collected only in the fjord, or later only on the shelf, or only at certain depths, and various expedition participants come with large or even larger bottles to get their share of water as well …

The important task of keeping record, not only for CTD sampling but for just about all samples taken during the expedition, falls to Kate Hendry. Kate is an ocean climate scientist, chemical oceanographer or biogeochemist at the British Antarctic survey. She is part of the science and steering groups of DEHEAT, and has also been designated as the expedition’s second chief scientist.

Kate Hendry (British Antarctic Survey) serves as co-chief scientist and general data manager during the DEHEAT expedition with RV Belgica.

Kate explains what that means: “The co-chief scientist position involves being there as a sanity check and a sounding board for the chief scientist. On an expedition like this, there is a lot to think about and keep an eye on, and there are a lot of important decisions to be made. My task is to come up with ideas, suggestions, alternatives, solutions to any problems that may arise. But to be honest, Sebastiaan is doing such a great job, so it’s not been too bad for me at all, it’s all running very smoothly”.

On the task of keeping track of all that’s going on, she adds: “Next to the science, I’m focusing on the data management, looking after the paperwork, making sure everything is archived. The last thing you want is some critical paperwork going missing, so I make sure everything is scanned and archived. This sometimes turns out to be even useful months or years after a cruise, when something confuses or puzzles people, creating a need to go back to the vital original logs”.

Back to the CTD sampling now. Felipe Sales de Freitas, chemical/geochemical oceanographer and postdoctoral researcher at the Université Libre de Bruxelles, is directly involved in the DEHEAT project and takes care of what can be considered the ‘small volume CTD sampling’ for a whole range of goals, most of which require the water from the Niskin bottles to be filtered.

“But first we have to go through the sacred ritual of rinsing every recipient or sampling tool three times with the actual water that is going to be sampled” he laughingly explains. “Next, we squeeze water through syringes and filters until our thumbs are completely cramped”.

Felipe further explains his role in the DEHEAT Belgica expedition as follows: In this expedition, I am basically an extra pair of hands in various sampling actions because of my experience in field sampling and analysis. Later on, I will use a lot of the output data of the sediment coring and water analysis for the DEHEAT geochemical modelling”.

Felipe Sales de Freitas (ULB) during the processing of CTD water samples.

Lei Chou, meanwhile, drags larger containers back and forth between the Niskin bottles and a more sophisticated filter setup that she provided herself, that is better suited to filtering larger volumes. She is a marine biogeochemist and emeritus professor of the Université Libre de Bruxelles and remains active and connected to both research and training of students.

Lei had very little time to prepare for the DEHEAT expedition but is making the most of it: “I was offered a berth on RV Belgica only weeks before the start of the expedition when a place suddenly opened due to the cancellation of another participant. I had to move quickly, sending two suitcases of equipment to Reykjavik as the Belgica had already left its home port of Zeebruges. After all, I want to take the opportunity to collect additional samples for suspended matter content, nutrients, metals and chlorophyll to complement the already very ambitious DEHEAT plan”.

Lei Chou (ULB) during the processing of CTD water samples.

We can rest assured that Icelandic seawater will hold far fewer secrets after the analysis of the DEHEAT samples.

DEHEAT 2023/02 – Prepping for Iceland

25 June 2023, 17h00 – It would be untrue to claim that preparations for an expedition at sea begin on the day participants embark. In reality, the preparations have been going on for a very long time, from thinking out the concept, writing the project proposal, preparing and submitting the application to use the chosen ship, to the concrete practical preparation of the expedition.

That last step is a titanic task, especially for an expedition with a large international character like the DEHEAT expedition. After all, materials had to be sent from various European locations to Zeebrugge and Reykjavik, everything had to be given a logical place on board, and a whole range of sampling equipment and laboratories also had to be prepared and set up so that they could be fired up into action immediately after the start of the actual expedition. In fact, a number of scientists already came on board in Galway for this purpose, to make the necessary preparations during transit from Ireland to Iceland.

But today the big day has finally arrived: all the scientists who will take part in the DEHEAT Iceland expedition are now casting their first glance at the RV Belgica, discovering the ship on which they will spend 17 nights and spend the intervening days giving their best.

RV Belgica in the harbour of Reykjavik, Iceland, 24 June 2023 (© RBINS/K. Moreau)

There are 22 of them, coming from universities and institutes from Belgium, the UK, Germany, Denmark and Sweden, but representing many more different nationalities. Some have worked together before during previous collaborations, but there are also many new faces.

No superfluous luxury to compile a photo overview with names, which immediately also makes it clear to the RV Belgica’s regular crew who is who. The overview is hung in the mess, just about the only place on board where everyone passes a few times every day. That way, everyone should see it regularly and be able to quickly connect names to the many faces!

The motley crew taking care of scientific duties during the DEHEAT adventure in Icelandic waters with the RV Belgica (© RBINS/K. Moreau)

Setting sail is not scheduled until tomorrow morning, but the first evening on board is immediately filled with great meaning. First of all, there is the necessary safety briefing by chiefmate Sam, during which everyone is informed on the various safety procedures and the expected conduct on board. We also all had to squeeze ourselves into a rescue suit, which at times produced hilarious scenes.

Also DEHEAT chief scientist Sebastiaan does not escape fitting the rescue suit 😉 (© RBINS/K. Moreau)

Next: the scientific order of the day. Chief scientist Sebastiaan summarises the set-up of the DEHEAT project, focusing of course on the crucial role of the RV Belgica expedition. Also the course and activities of the first sampling day are reviewed in detail.

Detailed review of the plans for the first sampling day of the expedition (© RBINS/K. Moreau)

Not only the deck, but also the RV Belgica’s labs will be fully staffed during this expedition. Proper organisation is indispensable to ensure everyone can work efficiently. Laboratory manager Astrid therefore takes the floor to explain the procedures and make proper arrangements.

Lab manager Astrid explains lab procedures (© RBINS/K. Moreau)

Enough for the first evening now! Let’s all take advantage of the last night which we can be sure is set in a stable environment.

DEHEAT 2023/01 – Using the ocean to reduce carbon dioxide concentration in the atmosphere

First RV Belgica Mission to the Far North

On 26 June 2023, an international team of scientists embarked on the first arctic mission of the new Belgian oceanographic research vessel RV Belgica. They boarded in the Icelandic capital Reykjavik and will spend 16 days in the fjords and on the continental shelf of Iceland investigating the possibilities of reducing the concentration of atmospheric carbon dioxide by enhancing the weathering of silicates in the ocean. This process has potential to contribute to the active mitigation of the ongoing global warming.

RV Belgica (© Freire Shipyard)

Climate change is one of the biggest global challenges of the 21st century and urgently requires ambitious, transformative, and collective action to limit global warming. In 2015, representatives from 196 countries gathered at the United Nations Climate Change Conference in Paris and signed a historic agreement to limit the increase in global average temperature to below 2 degrees Celsius compared to pre-industrial levels.

Meanwhile, however, emissions of carbon dioxide (CO2) still continue to rise and have reached atmospheric concentrations that are unprecedented in at least the last 800.000 years. Humanity is now at the point where preventing emissions of carbon dioxide and other greenhouse gases to the atmosphere – the “conventional mitigation” – is no longer enough to achieve the ambitious goal. We also need to actively remove carbon dioxide from the atmosphere using negative emission technologies to meet the targets set in the 2015 Paris Agreement.

Enhanced Silicate Weathering

One promising approach among negative emission technologies is Enhanced Silicate Weathering. This process takes advantage of the natural weathering of silicate minerals, whereby silicate dissolution consumes atmospheric carbon dioxide and therefore helps to remove it from the atmosphere.

The concept of marine Enhanced Silicate Weathering involves distributing silicate minerals onto the seafloor of coastal oceans. Recent experiments have indicated that weathering can be accelerated in this way. The idea is that the increased availability of silicates, leading to a higher alkalinity of the ocean (a higher capacity of the water to resist acidification), will enhance the uptake of carbon dioxide, thereby reducing atmospheric carbon dioxide concentrations.


However, it is still uncertain whether the high weathering rates observed in experiments actually occur in natural environments and how efficient the process would be in drawing down carbon dioxide. To address these uncertainties, a group of researchers from the Royal Belgian Institute of Natural Sciences (RBINS), University of Antwerp and Université libre de Bruxelles joined forces in the project DEHEAT ‐ Natural analogues and system‐scale modeling of marine enhanced silicate weathering.

“We aim at examining, for the first time, the feasibility and efficiency of Enhanced Silicate Weathering under marine conditions, taking advantage of the coastal ocean as a large‐scale, natural biogeochemical reactor” says DEHEAT-coordinator Sebastiaan van de Velde, of University of Antwerp and RBINS. “A second critical issue concerns the potential side‐effects on marine ecosystems, both positive and negative”, he adds.

With RV Belgica to Iceland

To shed light on these critical knowledge gaps, the DEHEAT-team put together a dedicated scientific expedition aboard the new Belgian research vessel RV Belgica to quantify the sediment geochemistry and mineralogy at a site that serves as a natural analogue for Enhanced Silicate Weathering: the continental shelf of Iceland, which is rich in basalt. Basalt is a volcanic rock that is suitable for the envisaged research in terms of silica content and weathering speed, so Iceland is an ideal place to visit in order to reach the objectives of DEHEAT.

DEHEAT sampling locations around Iceland during the 2023 Belgica expedition (© Google Maps 2023 – TerraMetrics 2023, DEHEAT)

The team, led by Sebastiaan van de Velde and expanded with scientific expertise under the form of colleagues and equipment of Ghent University, the British Antarctic Survey (United Kingdom), Universität Bonn (Germany), University of Southern Denmark (Denmark) and University of Gothenburg (Sweden), embarked on RV Belgica on Monday 26 June in the Icelandic capital Reykjavik. They will spend 16 days in fjords and on the Icelandic continental shelf and will return to Reykjavik on 11 July 2023.

During the expedition, the highly international and interdisciplinary team not only samples water, drills into the seafloor of Iceland and measures weathering rates in the sediment but also employs computer models to simulate seafloor weathering rates around Iceland. The collected data will then inform a large-scale virtual application of Enhanced Silicate Weathering in the Belgian North Sea using the COHERENS shelf sea model, that is designed for a wide range of applications in coastal and shelf areas and of which the development is led by researchers of RBINS.

During daily briefings in the conference room of RV Belgica, DEHEAT lead researcher Sebastiaan van de Velde (central back) evaluates the work of the day and informs all scientists on the sampling actions and experiments that are planned for the next day.

A Northern First

The scientific team’s ability to carry out this mission follows from the fact that the new research vessel Belgica is equipped for such interdisciplinary research and has a high enough autonomy to remain at sea uninterrupted for a sufficiently long time. From the moment the ‘new RV Belgica’ concept was conceived, bringing Arctic waters within the scope of Belgian and European research was an important objective. In this context, the documentation and research of climate change and the development of climate change mitigation measures were obviously key objectives, among other goals. To enable operations at the edge of the pack ice during the summer season, the RV Belgica even has light ice reinforcement.

RV Belgica’s northern journey to Iceland does not stand alone. Indeed, the ship left her home port of Zeebrugge as early as 6 June, first completing an expedition led by Ghent University’s Renard Centre of Marine Geology in which the sedimentary processes (past & present) offshore southwestern Ireland were studied, including in the area of the Belgica mounds (steep-flanked underwater mountains that were discovered using the previous Belgica). After a short stop in Galway (Ireland) and the transit to Reykjavik, the DEHEAT-leg of the international adventure kicked off. Next, RV Belgica will transit to Greenland where yet another scientific team will embark under the lead of the Marine Biology Research Group of Ghent University. They will investigate how climate change, and more specifically changes in glacial melt, will affect the carbon dynamics, biological communities and food webs in Greenlandic fjords, a typical Arctic marine ecosystem (project CANOE). The return of RV Belgica to Zeebrugge is foreseen for 13 August.


DEHEAT (as well as CANOE) is funded by the Belgian Science Policy Office (BELSPO) as beneficiary of a specific call that was designed to give an impulsion to the start-up of research on the new RV Belgica and to allow researchers to get to know the ship and her potential. DEHEAT runs from 15 December 2021 to 15 March 2026.

More information on RV Belgica can be consulted at the ship’s websites at RBINS (including live position information and webcam images) and BELSPO. The ship and its scientific activities can also be followed on Facebook and Twitter.

SEADETECT: Reducing ship strikes with whales

As part of the SEADETECT project financed by the EU LIFE programme, the Royal Belgian Institute of Natural Sciences will contribute to the development and validation of an automated detection system of marine mammals to prevent collisions between ships and cetaceans.

A fin whale gets stuck on the bulbous bow of a ship after a collision, arriving in the port of Ghent with it in November 2015. (© RBINS/J. Haelters)

Today, global economy is mainly based on maritime traffic which represents 80% of world trade in volume and 70% in value. This intense traffic involves a growing number of ships moving ever faster through the world’s seas and oceans, which markedly increases the risk of collision with cetaceans.

Collisions between vessels and whales often result in the death of the animals. In recent decades, shipping traffic in combination with the increased speed of individual ships has led to a doubling of the number of fatal collisions. Several studies have shown ship strikes to be the leading cause of death of cetaceans in some areas. For instance, ship strikes are the highest form of mortality for fin whales and sperm whales in the Pelagos Sanctuary in the Mediterranean Sea, an area for which France, Monaco and Italy concluded an agreement to protect marine mammals.

In the arctic, climate change is predicted to result in increased exposure of vulnerable cetacean species to collision risk. Worldwide, reductions in collision mortality will benefit whale populations which are still recovering from the effects of historic over-hunting, and continue to suffer from human induced habitat degradation.

Faced with this situation, the SEADETECT project is developing a new solution that should enable vessels to reduce collisions with cetaceans by 80%.

Preventing ship strikes

Collisions are often due to a combination of three factors: the ability to detect, the reaction time of the crew and the time it takes to maneuver the ship, all depending on the size and speed of the ship and the state of the sea. The SEADETECT project will develop three systems to reduce such collisions:

  • A system on board ships that will detect unidentified objects, in particular marine mammals, in real time.
  • A network of passive acoustic monitoring buoys located in high-risk areas at sea that will determine and triangulate the position of cetaceans in real time.
  • Detection data sharing software, fed by the future detections, to inform vessels in the area about the risk of hazards.
Set-up of the SEADETECT project for automated detection of marine mammals and obstacles, and anti-collision system for vessels. (© SEADETECT)

RV Belgica as pilot platform

“The automatic detection and anti-collision system will be used in the existing multi-sensory infrastructure of the national oceanographic research vessel RV Belgica and will be validated by scientists of the Royal Belgian Institute of Natural Sciences during the expeditions and monitoring campaigns of the ship”, Bob Rumes of the RBINS Marine Ecology and Management team (MARECO) clarifies.

The automatic detection and anti-collision system will autonomously detect cetaceans but also obstacles or floating objects such as containers to prevent collisions with ships. Thanks to a high-performance data fusion and processing system, this solution will make it possible to detect in real time a 2-metre long object on the surface at a distance of 1km, by day and night, even in complex maritime conditions (strong sea states or bad weather conditions). In addition, the researchers will also investigate the impact of a general application of this detection and anti-collision system on several target species as an alternative to other possible measures.

The RV Belgica will also be used as a test platform in SEADETECT. (©Belgian Navy/J. Urbain)

The SEADETECT project, led by the French Group Naval, will last four years and brings together ten partners from three European countries: Belgium, France and Italy. More information can be found on the project website:

The LIFE programme is a financial instrument of the European Commission, dedicated to supporting innovative private and public projects in the fields of environment and climate.

Photo exhibition RV Belgica, Nieuwe Gaanderijen, Ostend

From 10 May until 4 July 2023, you can visit the Nieuwe Gaanderijen in Ostend for the photo exhibition ‘Christian Clauwers: on the front line of global warming’, which focuses on the RV Belgica and marine science. All the images were made by explorer-photographer Christian Clauwers during an expedition on the Belgica, the Belgian research ship of the Federal Science Policy and the Royal Belgian Institute of Natural Sciences.

Address: Nieuwe Gaanderijen, Koning Boudewijnpromenade (Zeedijk) z/n – 8400 Ostend

Price: free

A floating laboratory

Christian Clauwers is not only a photographer, but also an explorer, speaker and author. He has already sailed around the world twice, visited no fewer than 114 countries on all seven continents, and explored some of the planet’s most remote islands. His work focuses on the fragile relationship – and potential conflict – between humans and nature.

Scientists on the front line

Christian Clauwers was given the unique opportunity to sail on the TalPro22 expedition that set sail for the Tyrrhenian Sea.  Aboard the Belgica, he captured both scientific research and the impact of the relationship between man and nature on film. The ship has more than 400 square metres of laboratory space and carries several high-tech oceanographic measuring instruments. For example, the rozette, a cylindrical structure from which sampling tubes and measuring equipment hang, can be lowered to a depth of up to 5,000 metres. It takes two hours to bring the measuring instrument back up, and this in conditions that can change rapidly. The ship is equipped with satellite technology that allows it to hold position to within a metre, even in the most difficult weather conditions. The photos let us take a look behind the scenes of these impressive experiments.

A must-see for anyone concerned about the future of our planet

But the expo is more than just looking at pretty pictures. Facing the sea, it is a call-to-action to take the fragility of our planet seriously.

Christian Clauwers: ” I want to give people the chance to witness what nature has to offer us and at the same time show them how precious it is. The series on the Belgica expresses this very nicely, because the scientific research carried out there makes that fragility of nature measurable. The scientists on board measure what I try to photograph, and now I photograph what they measure. It’s an exchange where the arrow goes both ways and that’s what makes it so fascinating.”

The expo shows the consequences of the human footprint and what is at stake if we do not act to tackle climate change. It is an impressive and inspiring example of how images can be used to raise awareness and change the world.

Research vessel Belgica meets white-beaked dolphins twice in 2022

After White-beaked dolphins were observed more frequently in Belgian waters in the early 21st century, the species recently became rarer again locally. Indeed, sightings of groups on 23 June and 14 December 2022 represent the first sightings of living White-beaked dolphins in Belgian waters since April 2018. On both dates, the animals were seen from the new research vessel RV Belgica.

White-beaked dolphins (© Diederik D’Hert)

On Thursday 23 June 2022, a group of around ten White-beaked dolphins was spotted from the research vessel RV Belgica in the Belgian part of the North Sea. The dolphins were seen about 5 km off the coast of Knokke, while the ship was en route to her baptizing ceremony in the god city of Ghent. The animals swam in a westerly direction, regularly emerging above the water. Present ILVO researchers identified the dolphins as White-beaked dolphins, which was confirmed by a video that Belgian Navy Lieutenant-Commander Ilja Van Hespen was able to record showing the distinctive white snout and light flank markings with dark saddle.

On Wednesday 14 December 2022, researchers from INBO and RBINS were the privileged witnesses. Initially, some ten dolphins were spotted about 42 km from the Belgian coastline (measured perpendicular to the coast, this was at the level of Ostend), and they were already suspected to be White-beaked dolphins. Only when two individuals approached the ship closer a while later could this be substantiated, and also photographically documented by Hilbran Verstraete (INBO).


The White-beaked dolphin (Lagenorhynchus albirostris) occurs in cold temperate and subarctic waters of the North Atlantic, mostly confined to zones less than 1,000 m deep. Its range extends from the east coast of North America (northwards from Cape Cod), through southern Greenland and the waters around Iceland, to the European west coast from northern France to Svalbard. In the North Sea, they are found almost exclusively in the central and northern parts, where the population was estimated at 20,000 animals in 2016 (Hammond et al.; 2017). In the southern North Sea, the species leans towards the limit of its range and White-beaked dolphins are a more irregular occurrence. The White-beaked dolphin is rare in the English Channel.

More numerous and rare again

In the early 21st century, particularly between 2003 and 2011, the species seems to have been less rare in the southern North Sea for a while (Haelters et al.; 2018). In the period 2009-2018, 62 sightings of White-beaked dolphins were recorded in the Belgian part of the North Sea (Haelters et al.; 2019), with undoubtedly some double-counting, but in the last years of this time interval, the number of sightings experienced a sharp decrease to only 1-3 cases per year, with also some sightings just outside the Belgian North Sea area (Haelters et al.; 2016a, 2016b, 2017, 2018, 2019, 2020, 2021). Within the Belgian dataset, a clear peak can be observed in the first half of the year (January – May), but observations from almost all other months are also known. For the years 2019, 2020 and 2021, however, no more certain Belgian sightings of live White-beaked dolphins are known (Haelters et al.; 2020, 2021, 2022), two specimens on 19 April 2018 concerned the last sighting. Until the groups of 23 June and 14 December 2022. The White-beaked dolphin thus seems to have retreated more northwards again, possibly a consequence of climate change and its associated effects on the distribution of their prey (IJsseldijk et al.; 2018).


Dead White-beaked dolphins washed ashore (or floating at sea) have also recently become rarer in the southern North Sea. While between 2000 and 2013 an average of one White-beaked dolphin washed ashore annually in Belgium, only three cases have been known since then (29 November 2017 Oostduinkerke, 17 May 2018 De Panne and 4 March 2020 at sea off Middelkerke) (Haelters et al.; 2018, 2019, 2021). A decrease in strandings was also observed in the Netherlands (Keijl, 2016), after it was previously noted that the Bottlenose dolphin (Tursiops truncatus) disappeared from stranding lists at the beginning of the 21st century, coinciding with the increasing frequency of the White-beaked dolphin (Camphuysen & Peet; 2006). Whether in the southern North Sea there is actually a link between the opposite trends of the Bottlenose dolphin (which has recently also been noted more regularly in Belgium) and the White-beaked dolphin, however, we do not wish to infer from this.


Camphuysen, C.J. & Peet, G.H., 2006. Whales and dolphins of the North Sea. Fontaine Uitgevers BV, ’s Graveland, The Netherlands.

Haelters, J., Kerckhof, F., Jauniaux, T., Potin, M., Rumes, B. & Degraer, S., 2016a. Zeezoogdieren in België in 2014 [Marine mammals in Belgium in 2014]. MARECO rapport 16/01. 29 pp.

Haelters, J., T. Jauniaux, F. Kerckhof, M. Potin & T. Vandenberghe, 2016b. Zeezoogdieren in België in 2015 [Marine mammals in Belgium in 2015]. Rapport BMM 16/01 – MARECO 16/03. 26 pp.

Haelters, J., F. Kerckhof, B. Rumes, M. Potin & T. Jauniaux, 2017. Strandingen en waarnemingen van zeezoogdieren en opmerkelijke vissen in België in 2016 [Strandings and sightings of marine mammals and some remarkable fish species in Belgium in 2016]. Koninklijk Belgisch Instituut voor Natuurwetenschappen (KBIN), Brussel. 30 pp.

Haelters, J., F. Kerckhof, K. Moreau, M. Potin, M. Doom & T. Jauniaux, 2018. Strandingen en waarnemingen van zeezoogdieren en opmerkelijke vissen in België in 2017 [Strandings and sightings of marine mammals and some remarkable fish species in Belgium in 2017]. Koninklijk Belgisch Instituut voor Natuurwetenschappen (KBIN), Brussel. 30 pp.

Haelters, J., F. Kerckhof, K. Moreau, B. Rumes, M. Potin, T. Jauniaux & D. Vercayie, 2019. Strandingen en waarnemingen van zeezoogdieren en opmerkelijke andere soorten in België in 2018 [Strandings and sightings of marine mammals and remarkable other species in Belgium in 2018]. Koninklijk Belgisch Instituut voor Natuurwetenschappen (KBIN), Brussel. 34 pp.

Haelters, J., F. Kerckhof, K. Moreau, B. Rumes, Team SeaLife, T. Jauniaux & P. Cornillie, 2020. Strandingen en waarnemingen van zeezoogdieren en opmerkelijke andere soorten in België in 2019 [Strandings and sightings of marine mammals and remarkable other species in Belgium in 2019]. Koninklijk Belgisch Instituut voor Natuurwetenschappen (KBIN), Brussel. 34 pp.

Haelters, J., F. Kerckhof, K. Moreau, Team SeaLife, E. Lambert & T. Jauniaux, 2021. Strandingen en waarnemingen van zeezoogdieren en opmerkelijke andere soorten in België in 2020 [Strandings and sightings of marine mammals and remarkable other species in Belgium in 2020]. Koninklijk Belgisch Instituut voor Natuurwetenschappen (KBIN), Brussel. 34 pp.

Haelters, J., Moreau, K., Team SeaLife, Jauniaux, T. & Kerckhof, F., 2022. Strandingen en waarnemingen van zeezoogdieren in België in 2021 [Strandings and sightings of marine mammals in Belgium in 2021]. Koninklijk Belgisch Instituut voor Natuurwetenschappen (KBIN), Brussel.

Hammond, P.S., Lacey, C., Gilles, A., Viquerat, S., Börjesson, P., Herr, H., Macleod, K., Ridoux, V. & Santos, M.B., 2017. Estimates of cetacean abundance in European Atlantic waters in summer 2016 from the SCANS-III aerial and shipboard surveys. Sea Mammal Research Unit, University of St Andrews, Scotland, UK.

IJsseldijk, L.L., Brownlow, A., Davison, N.J., Deaville, R., Haelters, J., Keijl, G., Siebert, U. & ten Doeschate, M.T.I., 2018. Spatio-temporal trends in white-beaked dolphin strandings along the North Sea coast from 1991-2017. Lutra 61(1): 153-163.

Keijl, 2016. Jaaroverzicht walvisstrandingen 2016. Gedownload van, 28 maart 2017. Naturalis, Nederland.

North Sea Monitoring with RV Belgica – 2022/28

Some compiled images of colleagues from RBINS/ODNature, Ghent University and VLIZ on board of our brand new floating office ‘RV Belgica’ during the 2022/28 monitoring and sampling campaign on 7-8 November. These monitoring campaigns are conducted monthly.

The activities included collecting (and bottling) seawater samples at different depths during a tidal cycle, filtering for further analysis in the laboratory (BGCMon, BGPart), using eDNA for the detection of marine species (ZEROIMPACT), launching the LISST-Video Plankton Recorder (TURBEAMS) and testing of the EARS application (Eurofleets Automatic Reporting System), an event logger developed by the Belgian Marine Data Centre (BMDC) of RBINS.

Pictures by Marianne Schlesser (RBINS/BMDC)