Microplastic analyses on marine mammals from the Arctic (MiPaMar)

Project description

Plastic pollution is now known worldwide and is an omnipresent problem for every ecosystem. In 2021, the annual plastic production was 390.7 million tonnes. A distinction is made between macroplastics (> 5 mm), microplastics (MP; < 5 mm) and nanoplastics (in the nanometre range).
These plastic particles enter the marine environment via various routes, e.g. via wastewater, atmospheric transport, ocean currents, landfills and fishing activities. Once in the environment, macro litter is broken down into smaller particles because the polymer structure is weakened by photodegradation (UV), hydrolysis, mechanical abrasion, biodegradation (microorganisms) or biofouling (colonisation of plastics by microbes).
The polar regions were long considered to be largely unaffected by humans. Even though it is not a heavily populated region, MP has been detected in this ecosystem in a variety of compartments such as the water column, snow, sea ice and deep-sea sediments. The increase in temperature as a result of climate change and the associated melting of ice is causing various problems - in addition to the rise in sea level, the increasing decrease in sea ice is leading to the release of microplastics that were previously bound by the ice deposits. This is now "available" and enters the sensitive ecosystem - the consequences cannot yet be estimated. The presence of microplastics in the Arctic means that species in the polar region are now increasingly confronted with an anthropogenic problem - the presence of marine litter or microplastics and its consequences. This also includes Arctic peoples, whose diet also includes the meat and fatty tissue of marine mammals.
The aim of the project is to obtain valid data on microplastics and associated pollutants in marine mammals from Arctic waters and thus improve the state of knowledge in this sensitive habitat. The acquired knowledge is the basis for future trend analyses that are necessary to enable effective MP monitoring in Arctic waters. The following species characteristic of the Arctic will be studied: harbour porpoise (Phocoena phocoena), ringed seal (Pusa hispida), grey seal (Halichoerus grypus), harbour seal (Phoca vitulina), hooded seal (Cystophora cristata), bearded seal (Erignathus barbatus) and polar bear (Ursus maritimus). Another important aspect is the establishment of a method for visualising MPs in tissue. For this purpose, pieces of tissue from the gastrointestinal tract are prepared and examined both histologically and using a confocal microscope. Various staining techniques are then used to identify potential microplastics in the tissue. This is an important step towards better understanding the transport routes of microplastics and verifying entry paths.
The samples come from various co-operation partners such as the University of Iceland and the Norwegian Polar Institute. The pollutant analysis is being carried out by the University of Siena.

The analysis is included in Mathilde Piette's doctoral thesis (link).