NanoMare expedition: nanoplastics in the North Atlantic

Written by Helge Niemann 

We’re back on land. The pilot for Angra Harbour on the Azorean island of Terceira navigated our vessel to the pier, and the customs officers have also just left the boat. Everyone is itching to explore Terceira, to stretch out, see some other faces… But I have to say this: it feels a bit strange to leave this ship so soon. Anna Weber-van Bosse has been our home for the last four weeks, crossing the Atlantic Ocean from the polar regions north of Iceland and then always heading south… to 32°N, almost 1,000 km southwest of the Azores.

We spent about 150 hours on station, launching a series of instruments: CTD, high-pressure samplers, different nets, box corer… watching the first data come back from the sensors. And then countless hours in the labs afterwards, starting one set of incubations, finishing another—night shifts to modify and repair gear. We fell into the rhythm of the ship, the daily routine of changing watches, mealtimes structuring the day like a metronome.

It feels like yesterday that we boarded the ship in Reykjavík, but almost 6,000 km are behind us—an entire ocean basin. And you can see that: those who were at sea for the first time walked with slightly wobbly legs when the first waves rocked us… back then, still in Icelandic waters. Now everyone has sea legs. Our equipment is, for the most part, packed up and stored in boxes and containers. Colleagues are embracing each other, and you can sometimes even see a tear glistening… In a way, that is a good sign - a team has been forged.

It was a fantastic cruise, with a nice atmosphere among the scientists and also with Anna Weber’s crew. Smaller and bigger technical problems were solved, and we were able to collect a wealth of samples and data. I can’t wait to see what we found. How much nanoplastic is there in the Atlantic? What effect does it have on microbes and algae? But the answers to these questions must wait.

It’s good to relax now, to get out of the 24/7 working mode, not to plan the next station or discuss data and instrument problems. I’ll spend a few days in the Azores, hiking and slowly coming back down to earth.

Written by Yu-Hsin Huang

A gentle breeze brushed against my cheeks, while warm sunlight spilled softly across my face, leaving it tingling as though gently tickled. I sat on the deck, reflecting on the days that had passed. It felt as if everything had happened in an instant, yet somehow, it also felt like we had already been out at sea for quite some time. We are almost there, approaching our final destination: Terceira, Azores.

The expedition really started for me at Station 1, in the Denmark Strait east off Greenland. We collected seawater using High Pressure Incubators (HPI), in a way a bottle that is made of titanium and designed to collect seawater from targeted depths (ranging from 4,000 meters to 50 meters). These bottles preserve the original pressure of the targeted depth, allowing me to carry out incubation experiments with nanoplastics under in situ conditions.
The goal of this project is to understand what happens to nanoplastics during microbial degradation and whether marine microbial communities from different environments, i.e., varying in depth and climate, are capable of degrading nanoplastics.

Our work usually began several days before sampling. We prepared the HPI bottles and loaded everything onto the CTD rosette, so that it was ready for deployment early the next morning. Preparation often lasted until midnight, so my teammates, Zakiya and Isabella, and I started calling ourselves the “Nanococktail” team. To keep our spirits up during these late nights, we created our own chant, played loud music, did Taiwanese morning exercises, and planned our next movie night. Although this was my third research cruise, it was my first time leading a team as a PhD student. I learned that maintaining team spirit is one of the best ways to work efficiently, especially during long and demanding days. Of course, I was also very lucky to have such a wonderful team; this work would not have been possible otherwise.

We recently completed our final sampling station, collecting 144 HPI bottles and 72 glass bottles. During the busiest period, we worked almost continuously from 8 AM until midnight for two days. There were many changes to the plans, which is something that often happens during a research cruise, so staying flexible became another important lesson. Despite the shifting schedules, we managed to adapt our sampling times, stayed focused, and still enjoyed the process.

We did it!

We are proud, but at the same time, a little sad to see this journey coming to an end. Although there is still laboratory work waiting for us in the coming days, it feels as if the expedition itself is nearly over.

Besides the late nights in the lab, we were also able to enjoy ourselves in this vast blue mystery. We saw pilot whales and countless flying fish; the latter reminded me of home, Taiwan. My first two cruises were in the Pacific Ocean, while this time I had the chance to sail across the North Atlantic.
That is the beauty of oceanography: it allows you to see the world from different perspectives. Places may seem far apart, but when you look more closely, you realize how deeply connected they are. At the same time, you also realize how small we are, or perhaps, how “nano” we are in comparison to this immense blue mystery.

Yet everything adds up. Every observation, every phenomenon, every question. And I hope that one day, together, we can reveal a little more of this God’s blue creation.

Written by Georgina Panagiotounakou

I am writing this halfway through our expedition with the research vessel Anna Weber van Bosse from Iceland to the Azores. There hasn’t been a moment when I didn’t feel incredibly lucky to be part of it, even when God Poseidon was angry, making the boat roll like we were being stirred in a big pot. Only a bit annoying that I cannot always enjoy Mihai’s (our cook) tasty food…But what makes this cruise an unforgettable experience is mostly the people. It brings me so much joy that we are such a good team, both among crew members and fellow scientists.

I have two sampling methods to accomplish in this expedition: A Manta Trawl to capture particles from surface waters and a Multinet for deeper waters, all the way to 300 meters. While I am mostly investigating the mass distribution of microplastic particles, my nets catch many plankton species as well -after all, both the Manta and Multinet are traditionally used for plankton, anyway. For my work, it is important to investigate the plastic-to-organism ratio, which describes, in simple words, how much life there is in comparison to microplastics and how harmful these particles might be for plankton. And believe me, there’s plenty of life under threat!!! However, for exact results, I will have to wait until I am on shore to process my samples. Until then, I can only enjoy the sample collection, which I must say is probably the most fun part of my journey! After this expedition, I can actually share stories about the dangers our oceans are probably facing because of the man-made plastic pollution, which I have now seen with my own eyes. 

Fast forward: My first sampling day is here, the 17th of August, and I’m stressed: Is everything prepared? Are the cod ends for collecting the samples well attached to the nets? How are my samples going to look like?

All these questions are running in circles in my head. The first Manta trawl was successful; such a relief. Sadly, the Multinet seemed to have other plans. Three hours of staring at the software screen just to realize that no sample had been taken because we forgot to unlock the nets. Luckily, we had time to do it all over again. As my supervisor Peter said through a video call while he was all the way sailing the Pacific for the same reason as me, “the first sampling is like the first pancake you bake, always a little miehhh” … After that, everything has been running smoothly!

Manta sampling is a lot of fun, as the monitoring of the net (checking if it flows well) is accompanied by sea gazing, a bit of Vitamin D absorption, and nice music from the beautiful hand-made speaker that René (electrical engineer) and Jacco (one of the sailors) made. Based on René’s idea and design, they literally glued together old pieces of wood to create the box and then added a grill grate from the kitchen, a piece of metal winch, and a few good electrical components fixed together by René. We can put on music streamed from our phones, and often listening to music comes along with singing or even dancing!

At other times, we just talk with each other while waiting to recover the manta net. On the contrary, multinets are less fun as I am staring at a screen all the time during their deployment. However, good company in the lab and watching the depth of the Chlorophyl maximum on the screen make the multinet procedure “a time well spent”. One time, I could even see ‘little creatures sneaking with their helmets’ to watch pilot whales. I am actually writing this during a multinet deployment; my eyes move from screen to screen while in between I say things like “winch can go down with speed 30 meters per minute”, or “you can stop the winch now”; how beautiful does that sound?

So, our days go on, following pretty much the same routine. However, our evenings have a different taste. The gym on R/V Anna Weber has caught our attention. My favorite workout is boxing, and if schedules align, I go together with Annalisa and Samuele and our coaches Dali (sailor) and Jacco. Otherwise, we coach ourselves ;) If you don’t find me there, I’m probably watching a nice movie, or bonding with the fellow scientists in the lounge, or I’m snacking in the mess room. As we have been going South from Iceland and are now at 41° N latitude, almost at the same latitude as the Azores, the night sky is finally darker. So, I hope to be stargazing from now on, hopefully seeing the Milky Way without light pollution!

Four years ago, I wanted to find a bachelor’s project about plastic pollution (I did not), and three years ago, I dreamed of being on a research expedition in the Aegean Sea (I wasn’t); But look at me now, in the middle of the North Atlantic Ocean working on my master’s project on plastic pollution!! All in all, I feel grateful for my previous choices and all the experiences that finally brought me to this present, and I’m excited for the future. How much microplastic is there in the ocean compared to nanoplastic? What are the dominant sizes and materials of plastics in different regions and depths? Does the mass distribution of microplastic differ between the subpolar and subtropical gyre that we are crossing? How does plastic distribution vary between surface and deeper water layers? These are all questions that I hope to help answering with this project. Helge (NanoMare) and Peter (Ocean Cleanup), I hope I don’t let you down! Until the next one, xxx Georgina.

Written by Helge Niemann, Chief Scientist during cruise AW-109 

I escaped the heatwaves in the Netherlands, apparently the new normal, even if some people do not like to admit it. But that is another story… We went out into the North Atlantic for another reason: plastics.

We have all heard about it: plastic waste floating in our oceans and its negative consequences for marine life. A never-receding avalanche of waste pours out of our civilisation into the sea. Larger plastic objects float at the sea surface, drift with the currents and are broken into ever-smaller fragments by the sun’s scorching UV light and the smashing force of the waves. In this way, larger pieces become smaller; macroplastics become microplastics, until…

…well, until what?

We already discovered that at least some of these larger macro- and microplastics are broken down into particles smaller than one-thousandth of a millimeter. That is very small. Imagine a thin human hair: it is at least 50 times thicker than one-thousandth of a millimeter. These tiny plastic particles - smaller than one-thousandth of a millimeter -are called nanoplastics and are invisible to the naked eye.

Nanoplastics also behave rather oddly. Larger plastic objects usually floats or sinks. For example, plastic bags are often made of polyethylene (PE) and float, while soda bottles are made of polyethylene terephthalate (PET) and – if not closed with a lid - sink. But nanoplastics neither float nor sink, regardless of whether they consist of PE, PET or another type of plastic. Nanoplastics behave like milk in coffee: the milk’s tiny fat droplets remain evenly dispersed, neither immediately rising to the surface as cream nor sinking to the bottom of the cup.

For the ocean, this means that nanoplastics can be distributed throughout the water column, from the sea surface to the deep sea. Almost all marine life may therefore come into contact with nanoplastics. We found that nanoplastics constitute the lion’s share of plastic pollution in the North Atlantic (ref. ten Hietbrink et al., Nature 2025). However, we do not yet know exactly how much nanoplastic is out there globally or how it affects marine life.

Are nanoplastics concentrated near the ocean surface, where they form from macro- and microplastics? Do nanoplastic concentrations differ when comparing for example arctic, temperate and subtropical regions? How much has already reached the deep sea? What happens to microbes - the base of the marine food web - when they are exposed to nanoplastics? What is the fate of nanoplastics in the ocean: do they eventually break down completely?

These are some of the many questions that we are trying to answer with the data collected during this expedition. Funding from the EU has allowed me to establish the NanoMare project and bring together an excellent team of scientists - and we are fortunate to conduct this expedition aboard the shiny new flagship of the Dutch research fleet, RV Anna Weber-van Bosse.

Over the coming weeks, we will breathe science: collecting samples, making measurements, discussing our findings and starting experiments. And we will cover a wide geographical range, from the ice-cold Arctic waters to the balmy subtropical waters around the Azores - during expedition AW-109.