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PhD thesis defence Susanne Kühn
Susanne Kühn has been involved in the fulmar research conducted at Wageningen Marine Research (WMR) since 2011. Between 2016 and 2020, she was working on her PhD research, supervised by Jan van Franeker. Her PhD thesis, titled: ‘Message in a belly – Plastic pathways in Fulmars’, is now ready and Susanne is going to defend her thesis during a public defence in Wageningen on Friday 30 October at 11:00 am.
Fulmars on Iceland
In 2011 Susanne started as a Bachelor student at WMR, studying the plastic content of fulmars she had collected in Iceland from accidental longline bycatch. This early research made its way into her PhD thesis together with some other projects she was involved at that time. Examples include research on plastics in fulmars from Svalbard in 2013 and a detailed analysis of polymer types ingested by fulmars and other marine organisms. In 2016 she was given the opportunity to continue her research for another four years during a PhD studentship, as part of the European JPI Oceans project PLASTOX.
Plastic uptake through prey fish
During her PhD research, Susanne tested the possibility of plastic uptake by fulmars via their prey fish. Although some fish do ingest plastics in the North Sea and the Arctic Ocean, it was discovered that the amount and size of ingested plastics by fish may not contribute substantially to the total amount of plastics encountered in fulmars.
Transfer of chemicals
Fulmars ingest plastics regularly and one of the most pertinent questions concerns the potential harm caused to the birds. In cooperation with the German-Dutch plastic lab Carat and the Norwegian Research institute SINTEF Ocean, Susanne produced a microplastic mixture by collecting, milling, and analysing plastics found on the beach. This mixture represents plastics from the ocean in a realistic manner. Beside various sizes and shapes, this mixture contained a broad variety of added chemicals, so-called additives, that enhance certain characteristics of plastic such as colour, flexibility, and flame retardance. In an experiment, this mixture was added to the gastric fluid of fulmars. Results showed the transfer of different substances, including plasticizers and flame retardants, from the plastic to the gastric fluid, therefore demonstrating that the uptake of toxic substances into the fulmars’ body can occur.
The defence
All results can be found in the PhD thesis of Susanne. During her defence, there will be a short presentation to introduce the topic to the public. After that, four scientists will ask critical questions and discuss the results with Susanne for 45 minutes. The entire defence, including the ceremonial part, will take about 1.5 hours. Interested people are invited to follow the defence via the livestream link.