Two new PhDs in one day! Annkatrin Weber and Christoph Schür defended their PhD theses today at Goethe University Frankfurt. And, in a rare pandemic break, we were allowed to meet, discuss and celebrate in person. Amazing research, excellent defences and wonderful companions… Well done, Drs!
Happy day today: Our Lisa (Zimmermann) defended her PhD thesis on the toxicity of plastic consumer products! So many new, exciting and important insights into the safety of plastic chemicals (or lack thereof)! Proud co-supervisor from afar, I wish I could have been there in person…
Today, our Master student Ingrid Erichsen successfully defended her Master thesis on “The effects of textile microfibres on essential physiological processes in Calanus finmarchicus“. The censors awarded her thesis and exam with an A! Happy student and proud supervisors (big thanks to co-supervisor Iurgi Imanol Salaverria-Zabalegui)!
Here is the abstract of Ingrid’s thesis
Microplastics (1–5000 μm) is a common type of marine pollution that has the potential to affect the health of marine biota. Various marine species have been shown to ingest microplastic debris which can affect several essential physiological processes such as feeding, growth, development, and reproductive processes. Therefore, it is important to assess if ingestion of microplastics can affect these processes in key species of the marine ecosystem. The cold-water copepod Calanus finmarchicus converts low energy carbohydrates and proteins from phytoplankton into large and specialized lipid stores during the algal blooms. These lipid stores are an important source of energy and nutrients for other marine species and provide an essential trophic link in the marine pelagic food web of the Northern hemisphere. C. finmarchicus has been found to ingest microplastics (MPs) of various shapes and sizes, however more research is needed to understand the effect microplastic ingestion has on this species. Microplastic fibres have been found to be the most predominant shape of microplastic in the water column and sediments of the marine environment. However, there is a knowledge gap on the effect microplastic fibres of different polymer compositions have on marine species. Thus, the aim of the current study is to assess whether an exposure to selected textile microfibres (MFs) of different polymer composition (polyamide (PA), polyester (PES), and untreated wool) affects C. finmarchicus in terms of microalgae feeding as well as essential physiological processes such as growth, development, and lipid accumulation. Copepodites from developmental stage 3 (C3) were exposed to MFs of similar shape and size at two concentrations (37 and 150 MFs/mL) in the presence of microalgae (Rhodomonas baltica and Dunaliella tertiolecta). The control group was offered only microalgae. All copepods were sampled when 50 % of the control animals had reached adulthood (C6), 26 days after the start of the experiment. C. finmarchicus exposed to the high concentration of synthetic MFs PA and PES ingested significantly less algae than control animals (PA p=0.03, PES p=0.003). Animals exposed to the natural reference fibre wool ingested 3.7 % more microalgae than animals in control. In contrast, there was no significant difference in development rate or growth between control and exposed calanoids. However, adult animals exposed to the two synthetic MFs had significantly smaller lipid sacs than the those of the control group (PA p < 0.05, PES p < 0.001). Our results show that MFs of different polymer compositions influence several critical physiological processes such as the storage of essential lipids in C. finmarchicus.
Harini Pechiappan defended her thesis on “Effects of Nano- and Microplastics on Inflammatory Responses in Mactrophages in vitro” yesterday. The censors Aurelia Lewis and Tore Brembu awarded an A, the best grade in the Norwegian University system. Impressive work, great presentation, and happy supervisors!