Samples from key organs of an adult Bottlenose dolphin from the North Sea were analysed as part of the study.

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A new publication from researchers Dr Rebecca von Hellfeld and Christoph Gade has looked at how marine mammals are coping in increasingly contaminated environments.

Samples from key organs of an adult Bottlenose dolphin from the North Sea provided by the Scottish Marine Animal Stranding Scheme were analysed.

The findings show that marine mammals accumulate mercury in their tissues at high concentration and form the concentration dependent tiemannite crystals in order to detoxify.

Dr von Hellfeld explains: “Since the industrialisation, the global mercury emissions have increased. As mercury, and other heavy metals, are bioaccumulated, this has led to negative effects on environmental and organismal health in all affected ecosystems.

“Even with implemented conventions and legislations to reduce the use and release of mercury, the fact that mercury is not easily excreted leads to a higher contaminant burden in top predators, such as marine mammals.

“In our recent publication, we analysed tissue samples from an adult bottlenose dolphin (Tursiops truncatus) that stranded in 2020. The animal was thought to be at least 37 years old and was a well-known member of the Moray Firth pod.

“Preliminary findings suggest very high concentrations of mercury and other contaminants in these samples. We further analysed the samples using a scanning electron microscope, visualising the three-dimensional structure of detoxified mercury-selenium crystals (tiemannite) in these animals for the first time.

“A concentration-dependent trend in particle size was observed in all assessed organs, indicating the potential for primary tiemannite particles mobility and accumulation in different organs.”

Read more about the research here – High resolution visualisation of tiemannite microparticles, essential in the detoxification process of mercury in marine mammals – ScienceDirect

Notes for Editors