Ship's log MSM 107

It is Tuesday morning at 9 am. We meet in front of the MARUM in Bremen. Anticipation and a little nervousness are in the air. We will spend the next 18 days on a ship collecting important research data necessary to better understand climate change. We continue by bus to Bremerhaven. First to the Alfred Wegner Institute to pick up the remaining researchers and then to the harbor. There the research vessel MARIA S. MERIAN is already waiting for us. The RV MARIA S. MERIAN is named after the natural scientist and artist Maria Sibylla Merian, who is famous for her impressive drawings and paintings of insects and plants.

There is already a bustle of activity on board the ship. The RV MARIA S. MERIAN has been in the shipyard for almost two months, but should be ready for departure the next day. In order to be allowed to work and live on the ship, there is immediately a safety briefing from Sören, our first officer. After all, safety is a top priority while aboard a ship. Fire is particularly dangerous. Once you're out on the open sea, it's not easy to call the fire department to put out the fire. This is also where Nilu, the ship's doctor and surgeon, comes in. Injuries can quickly occur on deck and the hospital is far away.

After the tour, the container with the scientific equipment comes on board. Immediately, there is a bustle of activity among the researchers. Boxes are unpacked and equipment for research is set up. Everything has to be securely fastened, because the ship is always moving and even a small wave could knock the expensive equipment off the lab bench. And spare parts are also difficult to access on the high seas. In the evening of the day, we enjoy the setting sun from the palm deck and all fall tired into our bunks.

While we are slowly approaching our first station, Thursday and Friday consist of further preparations and many meetings.

The individual groups of researchers need to discuss with each other, the groups of researchers need to discuss with each other, and then the researchers need to discuss with different crew members. All of these meetings are important so that when they arrive at the first station, everything runs smoothly and everyone knows what they have to do. Until the time comes, crew and researchers are already getting along with each other in a light swell.

With record speed to the first research station off the West-Irish shelf

Entering the Atlantic Ocean and leaving the North Sea, which is often called a duck pond, wind and wave conditions change. Surfing on the tidal current, RV MARIA S. MERIAN reached a speed of 21.5 knots between Orkney and the Scottish mainland: a new record for this research vessel, which travels on average speed of about ten to twelve knots. While the RV MARIA S. MERIAN plows through the waves and starts rolling, some of the researchers experience contradictory sensory impressions. The human eye does not perceive the movement of the ship below deck, confusing the brain. The consequences are headaches and nausea. In strong swells, so-called seasickness brings many an experienced ocean explorer to his knees. But everything is only half as bad, because Nilu, our ship's doctor, is well prepared for this phenomenon. With appropriate medication, ship's zwieback and tea, all the explorers are soon on their feet again.

Next, it is the turn of probably the most important research instrument in oceanography. The so-called CTD rosette, which records conductivity, temperature, depth and other important parameters. This creates a profile of measured variables on the way towards the seafloor, giving researchers a good first impression of the station's water.

But there is no time to take a deep breath. While the CTD rosette is still in the water, the next instruments are being prepared for their deployment. At this station, the plankton net, which captures everything larger than 20 micrometers (abbreviated: µm), such as small crustaceans, and ROSINA, a particle camera, are still on the program. But more about that later.

At the speed of sound to the shelf

Even before the first station has been declared finished, Elda, Alice, Tilmann, Britt and Renée are sitting excitedly in the EDP center of the ship, waiting for the FS MARIA S. MERIAN to finally start sailing towards the shelf again. In contrast to the rest of the research team, Elda, Alice, Tilmann, Britt and Renée mainly work with remote sensing and thus with devices that are firmly bolted to the ship. These devices use sound to scan the seafloor and the water column above it. This research area is called hydroacoustics and will be combined with sediment research on this cruise.

The measured current profiles are confirmed by Tilmann with a special focused echo sounder. This can be adjusted so that emitted sound is reflected by water layers with different densities. In this way, surface water can also be distinguished from deep water. At the same time, a different frequency of the echosounder can be used to look up to 100 meters deep into the sediment. As before in the water column, density differences in the sediment can be used here to distinguish sand from clay or other rock layers, for example.

As we approach our first station on the western Irish shelf, many of the researchers have to crawl out of their bunks, having used the early evening hours to get some sleep. It is 12 o'clock in the night from Saturday to Sunday. By now, we have arrived on the shelf and again, the first CTD rosette of seawater is already back on deck. But the work has just begun. During the night and the next morning, water samples have to be processed again and various equipment has to be launched. 

After our first comprehensive station on the West-Irish shelf and the use of nearly all scientific equipment, the following experiments run well into the morning hours. Then, in the course of Sunday, a little calm returns. From 3 p.m., the mandatory wearing of masks also falls, after all persons on board the FS MARIA S. MERIAN have tested negative for Covid-19 over the first five days. As the weather continues to calm and the sun peeks out of the clouds from time to time, the deck comes alive. There is to be a barbecue in the evening to allow researchers and crew to get to know each other. This was previously hampered by mask and distance. The two excellent ship's cooks Matze and Georg as well as Silvia, our stewardess and "good soul" on board, serve up various salads and the finest grilled food. The food tastes delicious and everyone is happy to chat and enjoy the evening. Unfortunately, not everyone on board a research vessel like the FS MARIA S. MERIAN can spend the evening carefree. On the one hand, part of the crew must always be on call and on the other hand, such a ship must also be steered. Especially when the hydroacoustics research team wants to sail transects at a stable eight knots on the continental slope of the shelf during and after the barbecue.  

It seems that Alex knows every single plankton species personally by name. Through a microscope, she looks at a certain amount of the plankton sample at a time to determine the species diversity there, as different plankton species can vary greatly geographically. After Alex identifies a species, she notes the name and snaps a photo. You can find a small selection of the plankton Alex found on and off the West Irish shelf as photos in this blog.

The sea is sweet

During the first major research station on the open ocean off the western Irish shelf, experiments in the laboratories of the FS MARIA S. MERIAN are in full swing. Aman, Nguyen and Lennart, who work at the Max Planck Institute for Marine Microbiology in the Marine GlycoBiology (sugar biology) research group, are in the wet lab searching for multiple sugars in the sea. Because the sea can also be sweet at times. Just as plants on land store energy in the form of starch, marine plants, like algae, store their energy in polysaccharides. Similar to how a cube of sugar dissolves in coffee, these polysaccharides also dissolve in seawater. Polysaccharides are found in the ocean in such small quantities that they must be concentrated, i.e. enriched, before researchers can study them.

Aman, Nguyen and Lennart want to perform experiments with these polysaccharides: so-called incubations. In an incubation, they try to mimic the conditions in the ocean as closely as possible in order to then change individual environmental conditions in a controlled manner. In our case, the researchers want to determine how different amounts of polysaccharides affect the eating behavior of marine bacteria. This is because researchers have previously found that high amounts of polysaccharides can cause bacteria to stop eating altogether. This discovery could become interesting because it could keep bacteria and other marine organisms from converting the organic material into carbon dioxide. Thus, carbon could get out of the carbon cycle and be stored in the long term.

On the bridge of the RV MARIA S. MERIAN

Today, Wednesday, May 25, we are finishing the largest open ocean station to date. During the past 30 hours, all researchers and crew members have been working day and night. Samples were taken and all research equipment was in the water.

The procedure at a research station is first created by the chief scientist and then checked and approved by Captain Ralf for feasibility and permissibility according to the diplomatic approvals. Everything that happens on the ship goes through Captain Ralf and the bridge, where Senior Officer Ralf, 1st Officer Sören and 2nd Officer Bastian are on shift duty aboard the RV MARIA S. MERIAN.

The deployment of the research equipment is then coordinated from the bridge. Before we arrive at the research station, we will first "park" by hand to get the exact coordinates, but also a less wave-prone position of the ship. When we are on station, i.e. the ship is to hold the position, the bridge switches on the so-called "dynamic positioning". In this process, the POD drives align themselves with the propeler blades in such a way that the force of current and wind is perfectly balanced and the RV MARIA S. MERIAN remains in place. This is an important feature of a research vessel so that water and sediment samples can be taken within several hours at the same location. The RV MARIA S. MERIAN is very good at holding position, which provides us researchers with good samples. While Captain Ralf is in overall charge of the RV MARIA S. MERIAN, the engine is managed by Chief Engineer Benjamin and the deck by Boatswain Sebastian. Especially the communication and coordination between bridge and deck is important for the researchers on station, so that the station procedure is kept and the necessary safety is ensured when launching the equipment.

The day before, the "drift trap" was set. A sediment trap that drifts with the current and is collected again after about 24 hours. The drift trap sends out a GPS signal and can thus be located exactly. These coordinates are then entered into the navigation system on the bridge and the course of the RV MARIA S. MERIAN is aligned accordingly.

While we are sailing to the drift trap, some researchers are up on the bridge to ask Ralf and Sören some questions. To be allowed to sail as a crew member on sea, one way is to complete a training as a ship's mechanic (formerly sailor and engine keeper). After that, you can get a national patent at the maritime school, which qualifies you for further positions.

Apart from the official rules on board, there are also some customs, some of which you even take home with you. Even if you are not on duty. For example, it can happen that a shelf is chained up in one's own home to protect it from supposed swell. Although modern seafaring has almost nothing to do with the clichés of the old days, some peculiarities have survived. For example, "On deck, only the boatswain or the wind whistles," and an unburst champagne bottle at the ship's christening means bad luck.

When Christian, one of the researchers, discovers the drift trap, the excitement is great. Indeed, there is a competition on the bridge for the first sighting of equipment or targets. The drift trap is expertly navigated by Ralf and Bastian on the starboard side (i.e. on the right, for all non-seafarers) and then hoisted aboard by the explorers with a lot of help from the deck crew.

From big to small

Over the past few days, researchers have been able to observe one of the largest creatures in the sea from the deck of the RV MARIA S. MERIAN. In the early morning hours, the lack of sleep seems to cause hallucinations in some researchers.

When a particle is large and heavy enough, it begins to sink and starts its journey to the depths of the oceans. Morten, Christian, Lilli, Sandra and Onur use a variety of equipment to track down particles.

If ROSINA is now slowly lowered into the depths on a wire rope, it takes two pictures per second, giving the researchers a particle profile with the size and number of particles in the water column below the ship. Via a cable woven into the wire rope, Christian can view the images that ROSINA shoots directly in the laboratory of the RV MARIA S. MERIAN. This gives him a direct impression of what is going on beneath us.

From transport and degradation

We are approaching the end of the MSM107 research cruise. By now almost all research stations are behind us and we are heading for the last major station on the West Irish shelf. While we are on station, many gannets, fulmars, kittiwakes and skuas gather around the RV MARIA S. MERIAN. Presumably the birds are hoping for a quick bite of fish, which we cannot offer. So far only small snails, cold water corals or mussels came on board the ship with the sediment samples, but after a short observation they were immediately released back into their natural environment.

The degradation of this material is done by the very small organisms of the sea: the bacteria and archaea that feed and live on organic material. The speed of degradation depends on the prevailing environmental conditions in the surroundings. For example, bacteria and archaea find it difficult to eat organic material in oxygen-poor regions and easier in oxygen-rich regions. Both in the water column and in the seafloor, it can lead to low-oxygen conditions.

During decomposition, some of the organic material is converted to carbon dioxide, as it is in humans. Organic material, for example dinoflagellates, in the form of cysts or dead dinoflagellate shells, stick together to form aggregates or even particles. We call these aggregates and particles particulate organic material. These now sink driven by currents and gravity and are degraded in the seawater, but especially in the sediment.

Karin and Nicole can use various methods to determine which organism the organic material came from and how much of it has already been degraded. That's why the researchers sample the water column with four large in-situ pumps that filter between four hundred and one thousand liters of water and deposit the particulate organic material on a large filter. Because much of these particles end up in marine sediment, the researchers also take sediment cores using a device called a multicorer, or MUC.

On the MUC there are eight large and four small tubes made of metal and hard plastic slightly sharpened on the walls. As soon as the frame of the MUC with the tubes sinks into the seafloor, a sophisticated mechanism is triggered and a small flap snaps shut, sealing the tubes tightly. As it is pulled up, the trapped sediment can no longer slip out the bottom due to a sustained vacuum. However, for safety, another shutter is closed at the bottom of the tubes as soon as the MUC is pulled out of the seafloor. Sometimes it happens that the sediment is too hard or the device touches down crookedly on the seafloor. Then, unfortunately, the researchers come up empty.

Recently, Karin and Nicole have been researching the transport and fate of plastic in our oceans, in addition to the organic material of known origin. Plastic is introduced into the oceans by humans in a wide variety of forms. Larger pieces of plastic are transformed into smaller, so-called microplastics in the surface water mainly by sunlight, i.e. UV radiation. Like particles of organic material, microplastics sink to the bottom of the ocean through currents and gravity. But what happens to the plastic in the sediment is largely unexplored.

Not only carbon

We have finished our last stop and are about to leave the research area for Tromsø, where researchers of the next exit will replace us. Since the hydroacoustics researchers are still measuring as long as they are allowed to, the RV MARIA S. MERIAN initially sails at eight knots. Only at the border of the research area, the measuring instruments will be turned off, until the RV MARIA S. MERIAN has reached international waters.

Now the research vessel also picks up speed. In territories of other nations, such as the West-Irish shelf, a research permit must always be obtained in order to be allowed to conduct research. As the last experiments are slowly being completed, many are already beginning to pack their boxes. Materials and expensive research equipment are stowed tightly and securely for transport in the designated crates. The crates are stacked on pallets for mooring on the deck of the RV MARIA S. MERIAN. 

(nitrogen-loving) microorganisms and converted into nitrogen compounds biologically available to other organisms. Absorbed by microorganisms, nitrogen compounds and nitrogen-containing material are now distributed through the food web in the oceans. This is also how it reaches the seafloor and sediments, largely as particulate organic material. In the sediments, the organic nitrogen is either converted into elemental nitrogen or nitrate by bacteria and archea, or it is deposited in the long term. These intercalations can sometimes still be detected after hundreds of thousands of years and give us important clues about the climate of past times.

The researchers want to understand the ways in which nitrogen-containing compounds formed on the western Irish shelf change and degrade as they are transported to deeper parts of the ocean in the water, as well as in the sediment. Bingbing's research is similar to Hannah's and Jördis'. Bingbing is looking at the change and degradation of organic compounds in sandy sediments. However, again focusing on carbon and the carbon cycle. To do your research, Hannah, Jördis and Bingbing need to get to the sandy sediment. Here, the hydroacoustics researchers can provide crucial clues, as they can sense the soil properties with their instruments. Like other researchers before them, Hannah, Jördis and Bingbing take sediment cores using the MUC.

In the night from the first to the second of June, the RV MARIA S. MERIAN stops briefly in international waters. Christian lowers ROSINA one last time to previously unimagined depths of almost 3000 meters.

Afterwards, Captain Ralf and his crew set course for Tromsø. In doing so, we also cross the Arctic Circle. What is everyday life for polar explorers in summer comes as a surprise to some of them. The sun no longer sets here, and even at midnight the deck of the RV MARIA S. MERIAN is bathed in golden light.

At this point, the researchers would like to express their sincere thanks to the crew of the FS MARA S. MERIAN, without whose active support this cruise, but also marine research in general, would not be possible. A big thank you also goes to the cooks Matthias and Georg and our stewardess Sylvia, who made our stay on the RV MARIA S. MERIAN as pleasant as possible, both in terms of cuisine and hospitality. At the end we would also like to thank our readers. See you next time. Ahoy!