Low contamination of Antarctic krill with microplastics

Antarctic krill (Euphausia superba) is found in huge quantities in Antarctic waters and forms the basis of the food web there. The light-shrimps feed by filtering food particles from the water. As microplastic particles are of the same size as food, a research team led by Prof Bettina Meyer and Dr Sebastian Primpke from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), analysed krill stomachs. The result: only 4 out of 60 stomachs contained microplastic particles. In an elaborate series of experiments, the researchers compared various analytical methods in order to support the introduction of suitable, internationally standardised protocols for sampling and analysing microplastics in organisms and their habitats in the Southern Ocean and worldwide.

The team placed particular emphasis on quality control in the detection of microplastic particles using hyperspectral imaging Fourier-transform infrared spectroscopy. The researchers found that pooled stomach samples contained a large amount of particulate material, which upon closer analysis was not microplastic. Even in individual stomachs analysed, for example, they found undigested residues such as chitin, which could be mistaken for microplastics. Other residues, which probably originate from the krill’s lipid-rich diet, sometimes formed a film and made detection even more difficult. They therefore recommend selected additional filtration or digestion steps of the samples to prevent false positive results. This is necessary in order to develop standardised protocols for sampling and analysis so that Antarctic krill can serve as an indicator species for the input of microplastics into Antarctic waters.

Originalpublikation:

Primpke, S., Meyer, B., Falcou-Préfol, M., Schütte, W., Gerdts, G., At second glance: The importance of strict quality control – a case study on microplastic in the Southern Ocean key species Antarctic krill, Euphausia superba, Science of the Total Environment (2024). DOI: https://doi.org/10.1016/j.scitotenv.2024.170618