Carcass of Fin whale in port of Antwerp

A dead fin whale (Balaenoptera physalus) was found in the Deurganckdok in the port of Antwerp on Tuesday 29 August 2023. The carcass was lifted from the water by the crane vessel Brabo.

© RBINS/J. Haelters

The autopsy on Wednesday confirmed that the animal died from a collision and was brought into the port on the bow of a ship. Bruising was found at the level of the pectoral fin, and the spine was also fractured at that location.

“It was a young male measuring 10.5m and weighing about 8-9 tonnes,” said Jan Haelters, marine mammal expert of RBINS. “The animal was not healthy, quite a few parasites were found and the blubber layer was very thin.”

© RBINS/J. Haelters

The autopsy was performed by staff from the universities of Ghent, Antwerp and Liège, and civil protection provided technical support, in cooperation with the Port of Antwerp.

Due to heavy shipping traffic in the Bay of Biscay and the Mediterranean Sea, among others, collisions with large cetaceans are not uncommon. Also in 2009, a 20-metre fin whale ended up in the port of Antwerp after a collision. In 2015, the same happened in the port of Ghent, with an 11-metre fin whale.

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.

Science and industry join hands to investigate environmental challenges of floating solar at sea

To meet our society’s growing need for renewable energy, the potential of offshore solar power generation is being explored today. However, the technology has yet to be further developed, and we must ensure that this is done with respect for the marine environment. In the EcoMPV project, technological developments and environmental research go hand in hand. By working together in this pilot project, science and industry will learn to understand the impact of floating solar panels on the offshore environment and be able to avoid or mitigate their effects as much as possible from the start of potential commercial initiatives. The insights gained will allow positive effects to be immediately reinforced. The installation of three experimental modules at sea was completed on 28 June.

The growing need for the local production of renewable energy and an acceleration of the energy transition, combined with land scarcity, is leading policymakers, industry and scientists to increasingly focus on offshore sites. To date, renewable energy production at sea mainly involves wind farms. Belgium developed into one of the international frontrunners in this field.

Meanwhile, more attention is being paid to emerging opportunities to generate solar power at sea as well. The complementarity of wind and solar technology has been confirmed all over the world. As authorities increasingly promote multi-use of marine space, and the offshore grid infrastructure shows good potential for combined use, the integration of offshore floating solar installations in current and future offshore wind sites presents an opportunity to produce large volumes of additional renewable energy. However, both the technology and the knowledge on environmental impacts of floating solar are still in their infancy.

Artist impression of SeaVolt’s design for offshore floating solar energy

Environmental challenges

In the project EcoMPV (Eco-designing Marine Photovoltaic Installations), scientists and industrial partners work together to deepen the knowledge about environmental challenges related to offshore floating photovoltaic (PV) installations, aiming at technical solutions to mitigate undesired consequences and maximise beneficial impacts.

Knowledge gaps will be addressed about (1) altered underwater light field, hydrodynamics, pelagic biogeochemistry and primary production, (2) the artificial habitat provision for colonising fauna and fish, and (3) effects on carbon fluxes and sequestration. Furthermore, advice for eco-designing offshore PV installations, paving the way to its environmental licensing, will be formulated.

Preparing for the first floating PV installations

On 24 May, 28 May and 28 June 2023, scientists from the Royal Belgian Institute of Natural Sciences (RBINS) installed three experimental ‘littoral modules’ at the edge of the Mermaid offshore wind farm in the operational Belgian offshore energy zone. These floating modules are equipped with settlement plates in various materials, to study the colonisation potential for marine fauna and the habitat provisioning of artificial floating structures, including offshore floating PV systems.

Installation of an experimental ‘littoral module’ at the edge of the Mermaid offshore wind farm on 24 May 2023 with the RV Belgica. (© RBINS/MARECO)

The modules were designed and developed by Jan De Nul Group in collaboration with RBINS, with support of the EMBRC Belgium (European Marine Biological Resource Centre). The installation was carried out on board the RV Belgica and the Zeetijger, and they will remain in the water for around 1.5 year. The modules will be monitored at regular intervals to follow up the colonization process.

The location for the experimental tests has been chosen to be as similar as possible to the Princess Elisabeth Zone (PEZ), which is designated as a new zone for offshore renewable energy production in the Belgian Marine Spatial Plan 2020-2026. Although the focus of the PEZ remains mainly on offshore wind, seeking combination with floating solar panels seems promising.

Vincent Van Quickenborne, Minister for the North Sea: “With EcoMPV, important steps are being taken to also correctly assess the environmental impact of floating solar panels. This is important. The potential of floating solar panels is estimated to be high. If we want to use them later on a commercial scale, it is necessary to also take into account their effects on the marine environment in order to avoid or mitigate them as much as possible. With this, Belgium once again shows that economy and ecology go hand in hand.”

Tinne Van der Straeten, Minister for Energy: “In our country, we have the brainpower and the will to work out solutions to the challenges of the future. With the Energy Transition Fund, we want to kick-start those solutions. The federal government is supporting 21 top projects including EcoMPV. Floating solar panels at sea are part of the solution to make our North Sea the largest green power plant in Europe. EcoMPV shows once again that we can count on Belgian know-how and expertise for those solutions.”

About EcoMPV

EcoMPV is financed by the Energy Transition Fund of the FPS Economy, AD Energy, started in November 2022 and will run for three years. The project is coordinated by the research team ‘Marine Ecology and Management’ of the Royal Belgian Institute of Natural Sciences (RBINS), with Ghent University as a scientific partner and Tractebel, Jan De Nul Group and DEME Group as industrial partners.

The objectives of EcoMPV are the following:

  • Increase the knowledge on the effects of floating PV structures on hydrodynamics and phytoplankton productivity;
  • Investigate the habitat provision by floating structures to marine life, including colonising fauna and attraction by fish;
  • Describe effects of colonising fauna (fouling) of floating structures on the surrounding sediments, including the burial and sequestration (storage) of carbon in sediments;

Provide input on the Nature-inclusive design of floating PV systems, based on the results of the previous objectives, as to ensure the environmental sustainability of these systems.

Installation of an experimental ‘littoral module’ at the edge of the Mermaid offshore wind farm on 24 May 2023 with the RV Belgica. (© RBINS/MARECO)

The Energy Transition Fund saw the light of day in 2017, aiming to support energy transition research, development and innovation. A total of 51 proposals were received following the November 2022 project call. Of these, 21 were selected to be considered for grants. Through the fund, the expertise of companies and start-ups will be tapped to accelerate the energy transition.

Multiple discharges into the North Sea in recent weeks

Over the past few weeks, the surveillance aircraft of the Royal Belgian Institute of Natural Sciences (RBINS) documented a remarkable number of pollutions at sea. Especially in terms of oil pollution, these go against the trend of recent years. The observations illustrate the great importance of aerial surveillance over the sea.

On 20 June, a fishing vessel was caught red-handed while discharging oil in the Belgian Exclusive Economic Zone.

On 27 June, a large oil slick was observed but no polluter could be identified. This is one of the largest oil spills that did not result from an accident in Belgian waters in the past 15 years. The minimum volume discharged was estimated at 1.6 tonnes of oil.

General view of the large oil slick documented on 27 June 2023 (© RBINS/MUMM)
Detail of the large oil slick documented on 27 June 2023 (© RBINS/MUMM)

A day later, two ships were observed carrying out tank cleaning activities, resulting in discharges of vegetable oil and derivatives into the water. Whether or not these were legal will have to be determined by a port inspection. The discharge from one of the two tankers was initially detected in the morning by a European Maritime Safety Agency (EMSA) satellite. When the surveillance aircraft checked the vessel several hours later, it was found that the tanker’s tank cleaning operation was still in progress.

Detail of the contamination found on 28 June 2023 (© RBINS/MUMM)

In none of these cases was there a risk of the contaminants washing up on the coast.

Against the trend

The observed oil spills in recent days are in sharp contrast to the general trend shown by the results of 30 years of Belgian aerial surveillance. These illustrate that marine oil pollution has become a rare observed phenomenon in the last decade. The number of discharges of noxious liquid substances other than oil did experience a slight increase in recent years, with 2022 being the year with the highest number of observed discharges (averaged per flight hour) since observations began in 1991. Despite the fact that most of these discharges are probably legal, in line with international discharge standards, they nevertheless involve fluids that can be harmful to the marine environment to very varying degrees.

The observations in recent weeks should not necessarily cause us concern, as it may be due to coincidence that several offenders were active in Belgian North Sea waters in a short time span. However, these results do show that further close monitoring and enforcement remains required, both at sea and ashore. And so, also in the air, a fast-operating surveillance platform remains an absolute necessity.

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.

North Sea aerial surveillance in 2022

In 2022, the aerial surveillance team of the Royal Belgian Institute of Natural Sciences realised 244 flight hours over the North Sea. 19 cases of operational marine pollution from ships were observed, two involving oil and 17 other harmful substances. Suspicious sulphur levels were measured in the smoke plumes of 47 ships and suspicious nitrogen levels on 35 ships. The aircraft successfully participated in an internationally coordinated surveillance mission of the offshore oil and gas installations and an international chemical pollution detection mission. Furthermore, two seasonal marine mammal surveys were carried out, and the aircraft realised several ‘on call’ flights that included support to rescue transmigrants at sea. Navigation violations, entering prohibited zones and sailing without the mandatory automatic identification system were reported more in 2022 than before.

The surveillance aircraft in action over the navy vessel P902 POLLUX during a national pollution response exercise POLEX. (© Belgian Navy)

As part of the national aerial surveillance programme, 244 hours were flown over the North Sea in 2022. This programme is organised by the Scientific Service MUMM (Management Unit of the Mathematical Model of the North Sea) of the Royal Belgian Institute of Natural Sciences, in collaboration with Defence.

The majority of flight hours were national flights (220 hours). Of these, 211.5 hours were performed in the context of the Belgian Coast Guard. Pollution control came convincingly first (164 hours), with both monitoring of discharges of oil, other harmful substances and waste into the water (MARPOL Annex I, II and V respectively) and monitoring of sulphur and nitrogen emissions from ships into the air (enforcement of MARPOL Annex VI). Fisheries monitoring was also covered (42.5 hours on behalf of the Flemish Sea Fisheries Service), the aircraft was called up several times to verify marine pollution, to support transmigration rescue operations in French waters, and to locate lost Search-and-Rescue equipment (3 hours), and two hours of air support was provided during pollution control exercises. 8.5 hours were devoted to marine mammal monitoring.

International flights under the Bonn Agreement accounted for 24 flight hours in 2022 (see below: a Tour d’horizon mission and participation in the MANIFESTS Sea Trials).

Spills from ships

In August 2022, a few oil slicks were observed in the UK waters off Ramsgate during several flights, likely from a spill in the fuel tank of an old shipwreck. The case thus qualified as an accidental spill, and several British ships were involved in the clean-up. There was no direct impact on Belgian waters.

Two operational oil spills were identified in 2022, confirming the decreasing trend of the last decade (see graph). The first, very weathered, oil spill was observed at the estuary of the Western Scheldt in Dutch waters. The oil slick was not combatable and could not be linked to a polluter. The second oil slick was more limited and was observed in the Westhinder Anchorage area. It appeared to be linked to a bulk carrier at anchor. However, a check at sea by the Maritime Police revealed no new elements that could confirm the suspicion of infringement.

The number of observed oil spills per flight hour has dropped to almost zero. (@ RBINS/MUMM)

2022 resulted in no violations against the requirements of Annex V of the MARPOL Convention which covers the discharge of garbage and solid bulk substances. However, as many as 17 cases of operational pollution by noxious liquid substances other than oil (MARPOL Annex II) were observed. One of these could be linked to a ship in UK waters. The case was handed over to the relevant UK authorities for verification and follow-up.

In contrast to oil pollution, other noxious liquid substances are still a common problem, even on a slight upward trend (see graph). Although these are often, but not always, authorised ship discharges in accordance with international discharge standards, stricter discharge standards have been in force since 2021. This is particularly so for so-called ‘persistent floaters’ such as paraffin-like substances. However, no violations were detected on these in 2022.

Contaminants with other noxious substances follow a slight upward trend. (@ RBINS/MUMM)

Three oil slicks were also observed in Belgian ports: two in the port of Antwerp and one in that of Ostend. The two oil slicks in the port of Antwerp were observed during transit flights from Antwerp airport (the home base of the aircraft) to the North Sea. One of these two detections involved a group of three smaller slicks with five different ships in the vicinity. The spots could not be clearly linked to any of these ships. The other slick was spotted at the Antwerp gas terminal during a bunkering operation. The oil slick observed in the port of Ostend concerned a small slick with no polluter and was too limited to combat. All observations were immediately reported to the competent authorities to ensure follow-up.

Oil pollution in the port of Antwerp. (© RBINS/MUMM)

Monitoring of emissions to the air from ships at sea

By using a sniffer sensor in the aircraft, our country is considered a pioneer in the international fight against the air pollution from ships at sea (monitoring and enforcement of annex VI of the MARPOL convention). The sensor allows the measurement of various air pollutants in the exhaust of ships in real conditions.

The measurement of sulphur emissions has already been part of the programme since 2016. In order to monitor the strict sulphur limits that apply to ship fuel in the North Sea Emission Control Area (ECA), 61 sniffer flights (for a total of 91 hours) were carried out by the aircraft in 2022 over the Belgian monitoring area. Of the 965 ships whose sulphur emissions were measured, 47 had a suspiciously high sulphur content. These ships were duly reported to the relevant maritime inspection services and 13 were subsequently inspected on shore.

Belgian Coast Guard aircraft in operation during a ‘sniffer’ flight. (© RBINS/MUMM)

Thanks to the successful integration of a NOx sensor in 2020, MUMM’s aircraft can also measure the concentration of nitrogen compounds (NOx) in the exhaust plumes of ships in order to monitor and enforce the stricter limits that apply from 1 January 2021 in the North Sea Emission Control Area. Belgium has thus become the first country ready to monitor these stricter restrictions. Of the 963 ships for which nitrogen emissions were monitored in 2022, 35 suspicious values were reported.

Since 2021, a new sensor has been added to the sniffer set-up, namely the black carbon sensor. This sensor measures the amount of black carbon in the exhaust plumes of ships, which is a measure for the soot concentration. The soot concentration of 182 ships was measured in 2022. When exceptionally high soot concentrations are measured, the competent maritime port authorities are asked to take a sample of the fuel used. In 2023, these fuel samples will be analysed in the OD Nature laboratories in Ostend.

Exhaust plume of a container ship. (© RBINS/MUMM)

International missions

During the annual international ‘Tour d’Horizon‘ mission to monitor marine pollution from oil rigs in the central North Sea (in Dutch, Danish, British and Norwegian offshore waters), carried out under the Bonn Agreement in September 2022, the surveillance aircraft detected a total of 16 spills, of which 15 were oil spills and 1 was a spill of an unknown substance that could not be visually verified due to a low cloud ceiling. 13 spills could be directly linked to an oil platform. The three remaining slicks were observed without ships or platforms in the vicinity. All these observations were systematically reported to the competent coastal State for further follow-up, in accordance with international procedures.

Oil spill connected to an offshore oil installation during the Tour d’Horizon in 2022. (© RBINS/MUMM)

From 30 May to 2 June, the Belgian air surveillance participated in the international MANIFESTS Sea Trials for the detection of chemical pollution in Brittany (France). Participation in such exercises is crucial as pollution by substances other than oil appears to be increasing in frequency (see above), a large number of different chemicals are transported, each with a specific behaviour at sea, and regulations are very complex. During the MANIFESTS Sea Trials, various sensors on ships and flying units were tested at sea for their ability to identify different substances. The Belgian aerial surveillance aircraft made a constructive contribution, on which scientists can further optimise the sensors to better monitor chemical discharges in the future.

The mission in Brittany was combined with air emission monitoring at the border of the Emission Control Area, located at the entrance to the English Channel. Among other things, ships here have to switch to low-sulphur fuels. Sixty-two were checked, 18 of them in the immediate vicinity of the ECA border. Six of these 18 ships showed suspicious sulphur levels, and two high NOx emissions. These preliminary results illustrate that more monitoring at the ECA border is needed to improve MARPOL Annex VI enforcement.

Chemical slick. (© RBINS/MUMM)

Monitoring of Marine Mammals

In 2022, the RBINS conducted marine mammals surveys in March and October. Respectively, 235 and 45 harbour porpoises were observed, resulting in average concentrations of 3.3 and 0.8 animals per km² of observed area. This is a lot of harbour porpoises for a surface area similar to that of Belgian waters, yet largely overlapping: over 11,000 in March and over 2,000 in October. A relatively high number of seals were also observed in 2022: 20 in March and 40 in October. There has never been so many.

Observations during the March 2022 campaign: harbour porpoises in red and seals in yellow. (© RBINS/MUMM)

Extended maritime surveillance in the framework of the Coast Guard

Within the framework of the cooperation within the Belgian Coast Guard, the surveillance aircraft also contributes to broader missions of enforcement of maritime regulations and safety at sea. For example, in 2022, air operators reported 46 navigation violations to the Coast Guard Centre and the Directorate-General of Shipping (FPS Mobility and Transport). These mainly involved vessels ‘ghost sailing’ or anchoring in shipping lanes. As this type of infringement is on the rise, resulting in an increased risk of collisions, DG Shipping has been providing specific legal follow-up since January 2023.

In addition, 11 violations were also reported last year regarding entering areas at sea surrounded by a safety perimeter (e.g. the wind farms). This is also an increasing number, which can be explained, among other things, by the introduction of some new prohibited areas, such as the aquaculture farm (sea farm) off the coast of Nieuwpoort and the calibration area for scientific instruments off Ostend.

Intrusion of three fishing vessels into the safety perimeter of the Oostdyck radar tower. (© RBINS/MUMM)

Finally, in 2022, no less than 17 ships were also observed sailing without Automatic Identification System (AIS), which, among other things, helps to prevent collisions. 16 of these cases involved fishing vessels. Again, this is a further increase in a regrettable trend.