Hello from Wales, more precisely, from the Isle of Anglesey in the north of Wales. Here lies the School of Ocean Sciences (SOS) directly at the Menai Strait, where the ocean changes direction by 180 degrees four times a day. My name is Agnes, and I study Environmental Engineering in Munich and have decided to explore a new scientific topic with the GAME project. For someone like me, who is strongly interested in marine biology, it was quite a piece of luck to end up in a place with this high marine biodiversity. Every day, it seems like the sea breathes in and out – but mostly out as it is quite windy here, like a fresh salty breeze going through your hair.
Before arriving here, I never imagined that the nature in North Wales is such a mysterious beauty. It does welcome you to sit in the forests and watch the wind weave its way through the trees, rustling the leaves and casting shifting patches of sunlight across the moss and undergrowth. Sometimes you can hear the calls of birds echoing above, and the scent of damp earth and pine is carried through the air. Or you might walk across rolling green fields speckled with grazing sheep and wildflowers, then reach the rocky coastline where the sound of waves crashing against cliffs rises to meet you. Within minutes, you can watch the deep blue sea stretching below or observe the silver shimmer of sunlight on the water. If you want to experience some lonely time in nature, that’s your place to be. When the deep-hanging clouds allow it, you can even see the mountains with their peaks often veiled in mist, waiting for your visit. There is a certain calmness to the landscape that envelops you, encourages you to be mindful. But let’s take a break from my romantic view of non-cultured nature and give you some information about the life and work here.
Now, I live in Bangor, right next to a natural reservoir, perfect for running or just a slow walk to say goodnight to the sun and the cows who live there. But be careful, it is hilly in Bangor, even though I love to have a walk, the walk up the hill from the city back home takes a while. With the wind and respect to the hilly topography, I sometimes think about what it would be like to be a bird. It seems a perfect place for it.
Many people asked me about the weather before I came here. Wales has a reputation for rain, wind and clouds, but so far, the reality I experienced has been quite different. April and May had been surprisingly sunny and somehow dry. However, locals keep reminding me that summer is still coming. During a hike, one colleague quoted her mother saying, “There is no bad weather, rain just makes the hike more atmospheric.” As a German, I can only agree to this philosophy.
The people at the School of Ocean Sciences are just as welcoming as you can expect from the British. Everyone is willing to help, answer questions, and share ideas. The technical staff, Pete, Aled, and Steve, already provided invaluable support to me while I was planning and building the experimental mesh cylinder. Alice, a marine biologist who volunteers on the project, has also become a great help. Her expertise in identifying marine organisms perfectly complements my background in environmental engineering. My main supervisor, Svenja, and I meet regularly to discuss the progress of my work and solve the inevitable challenges that arise during a field experiment.
Speaking of challenges, I need to mention that, for me, this year’s GAME project is slightly different from the other participants’, as I do not have a team partner. This year’s project examines how underwater soundscapes, such as boat noise, or natural habitat sounds influence the species composition and abundance of sessile marine invertebrates. Each of the two active sound treatment levels plays at a specific temporal rhythm for 2 or 3 months, depending on site-specific restrictions. If there are two team members, then each chooses one of those treatment levels for their experiment. For comparison, there is always an additional treatment level, the ambient control. To ensure the project is feasible while maintaining research quality, I chose to focus on only two sound treatment levels: anthropogenic noise and the ambient background soundscape as the control. Hence, over the next three months, I will use underwater speakers to play back boat noise to simulate exposure to an anthropogenic soundscape at one of my two study sites. At the other site, no additional sound will be added to the existing ambient soundscape.
This experimental design allows me to examine whether differences in underwater sound conditions influence the settlement and growth of marine sessile organisms that attach to hard surfaces such as rocks or, as a substitute, settlement panels. My two experimental sites are located 500 meters apart to ensure acoustic isolation, meaning that the boat-noise playback will not influence colonisation at the Site of the Control Frame (Raft). However, as I am investigating whether boat noise influences community composition, it is essential to ensure that the two experimental sites do not differ substantially in their initial species pool. To assess this, I deployed larval-pool test panels for two weeks before the start of the experiment and identified the species that colonised them. Statistical analyses of these communities, together with information from previous studies conducted at the same locations and accounting for the unique tidal dynamics of the Menai Strait, enabled me to evaluate whether both sites experience comparable environmental conditions and larval supply.
The Menai Strait itself is shaping the local environment and is influencing the practical aspects of my research. Functioning as a channel that separates Anglesey from mainland Wales, it features tidal reversal. During these tidal shifts, water flows in opposing directions at different times, so that as the tide comes in, some water moves toward the strait’s central point. In contrast, simultaneously, other water recedes in the opposite direction as the tide goes out. This situation is comparable to a river that changes direction several times per day in response to the tides. But instead of being one river, the Menai Strait is more like two rivers that meet in the middle of the strait. Furthermore, the Menai Strait experiences some of the largest tidal ranges in the world, with a difference of up to 8 meters between low and high tide. On a personal level, I learned that misjudging the tidal schedule can make it difficult, or even impossible, to retrieve equipment, underscoring how closely the natural dynamics of the Menai Strait are intertwined with the day-to-day realities of conducting fieldwork here.
Alongside the sound experiment, I am deploying additional recruitment panels, which are replaced with empty panels every two weeks. The retrieved panels are transported to the laboratory, where Alice and I identify the newly arrived species. This tracks which colonisers are present in the water column at different times during the experiment, and it is always a surprise which new species are on the panels. One of the most rewarding aspects of the project is the opportunity to see ecological processes unfold over time. Looking at the small, settled organisms through the microscope is like peeking into another world. So far, the panels are full of tiny hydrozoans, barnacles, bryozoans and tunicates.
Being responsible for the experiment in Wales on my own gives me many opportunities to learn and grow as a scientist. I have gained experience in logistics planning, organising fieldwork around tidal cycles, constructing equipment, processing samples, and managing acoustic and biological datasets. I never thought there would be so much planning required for a single site-specific experiment, especially since the theoretical preparation had already been completed during the course in Kiel. Nevertheless, this experience has left me with a long to-do list and many opportunities for further learning. One advantage is the opportunity to work closely with other team members on the GAME project and engage in meaningful exchanges. Whether discussing similar or contrasting challenges, finding solutions, or sharing personal experiences, it is important to both offer advice and share your experience working on an international project, just as much as you receive guidance from others.
At the moment, the experiment is fully underway. The mesh cylinders are in the water, the sound playback is running, and the first settlement panels have been analysed. Over the next few months, I will analyse species, check the sound system, and try to start writing my master’s thesis. Wish me and my little invertebrate’s luck!
I am enjoying life in Wales, learning some new things every day, about British history and environment, and trying to make it up Bangor’s hill. Between the strong tides, the endless shades of green and the ever-changing skies, it is hard not to enjoy the nature of the north of Wales.
Welcome to Cádiz
When we arrived in Cádiz in April, we knew that we would be spending the next months working on an experiment about underwater soundscapes. What we did not yet know was how much of our time would be spent carrying equipment through the city, rebuilding experimental frames, solving technical problems and trying to convince various pieces of equipment not to end up at the bottom of the Atlantic.
Cádiz itself was a pretty good and beautiful place to start.
The city is located at the very tip of a narrow peninsula and is surrounded by the Atlantic on almost all sides. There are beaches almost everywhere, small streets leading through the old town, the harbour with its many boats and plenty of places where you can simply sit down and watch the sea. It did not take us long to understand why Cádiz is sometimes called La Tacita de Plata, the Silver Cup.
Our first evening was still fairly relaxed. After arriving and settling in, we went out together for a drink and explored a little bit of the city. It was a good introduction to our new home. The next morning, however, the relaxed part was over and GAME 2026 officially began for us.
Our project focuses on how underwater soundscapes may influence the colonization of hard surfaces by marine sessile organisms. To investigate this, we used standardized PVC settlement panels mounted on experimental frames and exposed them to different underwater soundscapes.
Over the course of the experiment, we monitored which organisms settle on the panels and checked whether the developing communities differ between the different acoustic conditions. The panels themselves were only 15 x 15 cm in size, but the frames, which were holding them while they were underwater, were much larger and required quite a bit of construction and preparation.
So, before we could investigate anything, however, we had to build everything.
Building the experiment
The first weeks in Cádiz were all about getting the experiment ready. Before the panels could go into the water, we had to prepare the equipment, rebuild the experimental frames and organize everything needed for the different parts of the experiment. Our setup consisted of large rectangular frames made from PVC pipes that carried the 15 x 15 cm settlement panels while they were in the water. In addition to this, we had speakers for the sound playbacks and ropes, buoys and weights that kept everything in position.
Although, there were frames left from a previous GAME project that was done in Cádiz, we decided to build new ones, which meant sourcing new material, cutting and assembling PVC pipes, preparing the panels and putting the different parts of the setup together. Some materials were bought locally, while others had to be ordered. This also resulted in one of our first small fieldwork adventures: transporting several metres of PVC pipes in a public transport bus through Cádiz was not exactly an everyday activity. We did not have a car at the time, and the large hardware store, where we bought some of the material, was quite far away, so getting everything back to Cádiz meant taking several buses while carrying long PVC pipes through crowded streets and vehicles. We bumped into things more than once, attracted a fair amount of attention and quickly realized that carrying several metres of PVC through a busy city is not as easy as it sounds. At one point, the combination of researchers, long PVC pipes and a local hardware store became what we jokingly refer to as the “Bus Hardware Store” episode.
Building the frames also taught us quite quickly that fieldwork rarely goes exactly according to plan. Some parts required a bit of improvisation and technical problem-solving, and when we reached a particularly stubborn technical issue, we even called Liam’s father in Germany for some additional advice. Although he was not directly involved in the project, his background in mechanical engineering and his experience with practical technical problems made him a useful person to call when we needed another perspective. A video call across Europe was not exactly part of the original plan, but it turned out to be a useful addition to our fieldwork toolkit.
At the same time as we worked on the set up, we were preparing the recordings of natural underwater soundscapes that would later be used for the experiment. For this, we built a deployment system consisting of a concrete-filled bucket, a wooden pole and a HydroMoth attached to the pole. The idea was simple: the heavy bucket keeps the structure stable on the seafloor, while the hydrophone records the surrounding natural soundscape above it. The practical part was considerably less simple. Several heavy loads of concrete had to be transported through Cádiz, and once the equipment reached the beach, getting the concrete-filled bucket into position was another workout altogether. We used a two-wheeled hand truck to move the heavy bucket across the beach and then into the shallow water. From there, we worked our way out by snorkeling and swimming, carrying and guiding the setup into position. The water was no more than about two metres deep, so there was no need for a boat.
The setup may have looked a little unconventional, but it was based on the plans we deleoped for recording natural soundscapes during the preparative course in March. After plenty of cutting, drilling, tying, carrying and assembling, the first major pieces of the project were finally ready. The frames were taking shape, the equipment was coming together and our first soundscape recordings were underway.
With the construction phase coming to an end, there was only one major question left: where exactly will we put everything?
When the plan changed
Finding a suitable experimental site turned out to be one of the more complicated parts of the project.
Our original plans involved a site in a nearby marina, but the situation changed when we were informed that construction work was planned close to the site. The associated noise would have interfered with the acoustic conditions required for our experiment, making the location unsuitable for our setup. We therefore had to move the experiment to a different location at relatively short notice. This meant adapting the setup and transporting the frames again. In the end, we found our new home at Puerto América, at the north-eastern tip of the city.
The change was a good example of how fieldwork can sometimes require a little flexibility. You can spend weeks discussing the experimental design, the set up and the site selection, but once you actually arrive at the water, there are always things that you could not have predicted from a map.
The new location gave us enough space for the experimental setup and allowed us to continue with the project. Hence, the frames were finally transported to Puerto América, weighted and installed.
Getting the frames into the water was actually much easier than building them in the first place. Once we had transported the frames to the harbour, we were able to get them into position and secure them relatively smoothly. The real challenge had been the preparation on beforehand: assembling the large PVC structures, attaching all the necessary components and making sure that everything was ready for deployment.
After weeks of preparation, the frames were finally in the water. The structures that we had spent so much time building on land were now ready to become the basis of our experiment.
From this point on, the focus shifted from building the experiment to monitoring what was happening around it.
Hydrophones, boats and one very expensive swim
Once the experiment was running, the HydroMoths became an important part of our regular monitoring. These small underwater recorders allowed us to record the acoustic conditions around our experimental frames and to measure the sound levels reaching the area of the experiment. This helped us to keep track of the underwater soundscape throughout the experimental period and to verify in hindcast what acoustic conditions the organisms on the settlement panels were actually exposed to.
Of course, regular monitorings also meant regularly getting the equipment in and out of the water. And this was when one of our more memorable fieldwork incidents happened. One day, Liam was alone at the harbour and had a fairly straightforward task: retrieve a HydroMoth, download the data and put it back into the water. Everything went well until the moment when the HydroMoth decided to make the last part of the procedure considerably easier for itself.
It slipped out of his hands and disappeared into the water.
We tried to retrieve it by diving down, but the visibility was extremely poor. Finding a relatively small piece of equipment underwater turned out to be much harder than expected, and despite our efforts, we could not recover it. It was certainly not part of the original plan, but fortunately, the experiment could continue. The lost HydroMoth has since become one of those fieldwork stories that is much easier to laugh about afterwards.
The regular monitorings also revealed how quickly conditions around the experimental site can change. One day, for example, we arrived at the harbour and found a boat parked remarkably close to our experimental setup, almost directly next to our buoys. Luckily, nothing was damaged and the boat did not cause any problems for the frames, but it was certainly an unexpected sight when we arrived.
Working in a harbour means that we are sharing the space with many other users, and sometimes the surroundings have a few surprises in store for us. Fortunately, most of them have been harmless so far.
From PVC panels to marine communities
The most interesting changes, however, did not happen above the water.
They happened on the settlement panels.
At the beginning of the experiment, the panels were simply pieces of PVC. We sanded their surfaces and standardized them so that they would provide suitable settlement substrates for marine sessile organisms. After deployment, there was not much to see.
Then the first organisms started to arrive.
During the first sampling events, we began to see the panels changing. Small organisms had settled on the surfaces, and the communities became increasingly diverse. Ascidians and bryozoans were among those colonizers that became particularly noticeable, together with worms, crustaceans and algae.
Suddenly, the panels that we had spent weeks preparing were becoming real pieces of habitat.
That was probably one of the most rewarding moments of the project. You knew exactly what a panel looked like before it went into the water. Then you retrieve it a few weeks later and had to figure out what has colonized it.
Some organisms were relatively easy to recognize. Others required a microscope, identification guides and considerably more patience.
Our supervisor was a huge help with this part of the project, especially when it came to identifying organisms that were less obvious at first glance. What initially looked like a small patch of something growing on a panel, could turn out to be an entirely different taxonomic group once you took a closer look.
And sometimes the organisms were simply fascinating to look at.
Despite the fauna and flora on the panels, we encountered small crustaceans, fish and other animals using the experimental structures as a habitat. One particularly photogenic shrimp even ended up on Liam’s hand during sampling.
The panels were therefore becoming more than just experimental units. They were small snapshots of the underwater world and the marine biodiversity around Cádiz.
The scientific question remained whether the different acoustic conditions influence the development of the communities. But before we could answer that, we had to document what was actually there.
And that meant sampling.
Sampling in the field
Our first sampling event made another aspect of fieldwork very clear: sometimes there is no perfect laboratory waiting for you at the harbour.
Since our experimental site was relatively far from the university facilities, we transported the equipment we needed directly to the field site by car. This included the microscope and the other equipment needed to examine, photograph and document the settlement panels.
There was no perfect laboratory waiting for us at the harbour. So, we built one.
We set up a small temporary workspace close to the experimental site and arranged everything we needed for the sampling. With the microscope, cameras, laptops, sampling equipment and the panels themselves, we quickly had our own little field laboratory ready to go.
Once everything was set up, the panels came out of the water. One by one, they were photographed, examined and assessed for the organisms that had settled on their surfaces. Some could be identified relatively easily, while others required a closer look under the microscope and a little more time.
The same basic procedure was repeated during the following sampling event, allowing us to compare how the panels had changed over time and which organisms had newly appeared or become more abundant.
Working directly at the field site also had its advantages. Instead of transporting the panels back and forth, we could examine and document them close to where the experiment was running and get an immediate impression of how the communities were developing.
Of course, the conditions were not always perfectly calm. Strong winds can make working at the harbour considerably more challenging, and this is where we really began to appreciate the Levante, the strong easterly wind that regularly affects the Cádiz area. By “appreciate”, we mean learning very quickly how much more complicated even a routine sampling day can become when the wind picks up. Even simple tasks require more coordination, especially when working with equipment and panels close to the water.
Nevertheless, the sampling days became one of the most interesting parts of the experiment so far. Every time we brought a panel out of the water, there was something new to discover.
The youngest member of the GAME team
There was also one very important member of the team who deserves a special mention.
During one of our most recent monitoring days, we had some unexpected assistance from a four-year-old.
While we were reading out the equipment, working on the frames and dealing with the usual collection of sampling tasks, our youngest helper decided that watching from the side was not enough. He wanted to participate.
So he did.
For a short time, we had officially found the youngest member of the GAME team. He may not have been able to explain the experimental design or tell us anything about sound pressure levels, but he was very enthusiastic about helping with the work. It was a small moment, but it was also a nice reminder that fieldwork is rarely as isolated as it can sound when described in a scientific paper. People around us had become part of the experience, whether they were helping with equipment, giving advice, asking questions or simply were curious about what two researchers are doing at the harbour with a collection of PVC pipes.
And occasionally, they became part of the team.
Life outside the frames
Of course, our time in Cádiz did not consist entirely of PVC, HydroMoths and sampling.
Living in Cádiz for several months also meant getting to know the city and the surrounding region outside the harbour. We spent a lot of our free time near the sea, whether that means going to the beach, playing sport or simply enjoying the city after a long day of fieldwork. With beaches, the old town and the harbour all within easy reach, there was usually no shortage of places to spend a few hours away from the experiment.
We have also used our time here to explore more of Andalusia. We visited Sevilla, where we could experience one of the region’s larger and more historic cities, and travelled to Tarifa, where we joined a whale watching trip and got to see some of the marine wildlife of the area from a completely different perspective.
Other trips took us to places such as Zahara de la Sierra, a small mountain town overlooking the reservoir, and Ronda, famous for its spectacular location above the deep El Tajo gorge.
These trips were a welcome change from our usual routine and gave us the opportunity to see a little more of the region we called home for the duration of the project.
The weather had certainly helped. Temperatures were regularly around 30 degrees, although the strong winds could make the conditions feel very different. After spending a day working at the harbour, a few hours at the beach were therefore not the worst way to finish the day.
Andalusia has also experienced some major environmental events while we had been here. Large wildfires affected parts of the region during the summer, although Cádiz itself was not directly affected.
Then there was the solar eclipse.
Cádiz experienced a partial solar eclipse, which gave us the opportunity to witness something very different from our usual fieldwork. For a short time, the attention of the two marine biologists was directed away from the water and towards the sky.
It was a nice change from looking down at the panels.
Poco a poco
Looking back at the time in Cádiz, the project had not developed exactly as we imagined it would.
We changed the experimental site. We rebuilt parts of the setup. We carried heavy concrete across the city. We improvised a sampling station outside. We dealt with strong winds, boats appearing where they were not supposed to be and one HydroMoth disappearing into the sea.
But at the same time, the experiment was running.
The frames were in the water. The HydroMoths were recording. The speakers were playing their experimental soundscapes. And the settlement panels slowly became colonized by marine organisms.
That is probably the most satisfying thing about seeing the project now compared with the beginning. In April, most of what we had was equipment, plans and a long list of things that still needed to be done. At the end, there was an actual marine community growing on the structures we built.
And all the observations that we made are now data that can be analysed.
Perhaps the best way to describe fieldwork in Cádiz is with a phrase we have heard and used plenty of times:
Poco a poco.
Little by little, the experiment was coming together.
Hasta luego, Cádiz!
Carlos & Liam
