Until 2019, the official seawall was still behind this building on Texel. But now the dike in front of it has been raised and the Royal Netherlands Institute for Sea Research (NIOZ) is surrounded by meters high green hills. Inside, low and dry, the Italian Annalisa Delre works in a small room on the first floor. She is a marine biologist and published in a recent study that UV radiation breaks down plastics in the ocean, causing these plastics to break down into even smaller particles and become increasingly difficult to trace. “I never expected it to get a lot of attention in the media,” says Delre. “It’s just a survey.” She has always had that modest, sometimes even shy attitude, she says: “Until I came to Texel in 2019, I was insecure and I didn’t speak English. What’s left? Red cheeks and an Italian accent.”
As the rain beats against the window, Delre talks about the missing plastic paradox: “It is known how much plastic ends up in the sea via rivers, wind or ships, but that number is much larger than the number of plastics that are actually measured in the ocean. So plastic is disappearing. Together with colleagues, I discovered that UV radiation is a process that partly explains this.”
Delre links her interest in plastics in the sea to her childhood. Every weekend since she was four, she and her parents and little brother went to a local hill on the coast, near Viterbo, where she lives in central Italy. “Behind that hill was a beach that seemed to be ours alone, it was so empty and deserted. We wore flippers, snorkels and goggles. Lying on the beach was out of the question. We snorkeled all afternoon looking for special animals such as starfish and sea turtles. Since then I have been connected to the sea and life under water.”
There is a moment of silence, she looks dreamily outside, where it has stopped raining. “As a child I played with a local school of anchovies. I observed them and danced underwater. My arm movements made the school of anchovies move like a flock of birds. As a child I could do that endlessly. As I got older, the school of anchovies got smaller and smaller. And when I was twelve she had completely disappeared. I couldn’t dance with them anymore. I was left with the question why that happened.”
Thousands of pieces of plastic
That curiosity about the decline of biodiversity has never disappeared. Standing with her hand in front of the ‘solar machine’, Delre explains how her experiments went: “I had bottles with sea water and I added plastic to them. Using a hole punch, I cut thousands of pieces of plastic so that they were the same shape and size. I put these in the bottles and put them under a UV lamp.”
She slowly clicks the door of the machine open and holds it ajar. “The UV radiation is 24 times as strong as the radiation that we on earth receive from the sun. We use that to speed up the experiment. An hour of exposure to the lamp is equivalent to a day in the sun. Every day, wearing large UV-resistant gloves, I measured the concentrations of gases released during the decomposition of plastic, such as methane, hexane and other hydrocarbons. Based on these gases, I calculated the rate of degradation of the plastic.” For example, Delre and her colleagues calculated that around 2 percent of plastic is broken down worldwide by UV radiation each year. “To date, 22 percent of all plastic on earth has been pulverized by sunlight.”
The fact that there are a lot of plastics floating around in the sea becomes clear once again in NIOZ’s plastics lab. Delre digs into boxes full of monsters acquired in water and on land: the Scheldt, Schiermonnikoog, Ameland, Schoorl and Vlieland. She is looking for the granules from the MSC Zoe, the ship that lost 345 containers in 2019 in which plastic granules were stored. She was found by her colleague, Rachel Ndhlovu. “Look, if we put this plastic granule under the microscope…”, a razor-sharp image appears on a screen that resembles the satellite image of a mountain range full of snow-capped peaks. “Then we irradiate it with light and we can identify the plastics based on wavelengths that are reflected.”
Read about the investigation following the MSC Zoe accident: All that stuff in the sea helps the oceanographer
Fascinating phenomenon
According to Delre, the link between radiation and plastics remains a fascinating phenomenon. Sometimes depressing, she adds. According to her, marine life is really affected by all that plastic. “I took a different turn in that from the rest of my family. Every family dinner we eat fish we caught ourselves, but I prefer to see them swimming and dancing.”
Delre is now no longer involved with plastics. She has just started her PhD research on methane in the North Sea. That is still unknown territory for Delre and the rest of science. “We are investigating with NIOZ how much methane is leaking from old natural gas wells. My job is to see how bacteria can prevent this methane from being released into the atmosphere.”
When Delre walks past the fourteen different labs in the basement of the NIOZ, she points to equipment, waves to colleagues and the enthusiasm can be read on her face: “I feel completely at home here. I’m not leaving here just yet.”