Aarhus University Seal / Aarhus Universitets segl

Otoliths and mussel shells as recorders of potential future pollution on a transect from Nuuk to the proposed Isua iron-mine

Freshly-caught shorthorn sculpin from the Nuuk Fiord. Photo: Jens Søndergaard
Lis Bach and Anders Mosbech in the laboratory. Anders is about to take out the otoliths from a shorthorn sculpin. Photo: Jens Søndergaard

Otoliths from fish and shells from mussels provide a unique record of trace metal availability over time. Many such trace metals are continuously built in and stored in the calcareous material of otoliths and shells as it grows, and these will therefore provide a time-resolved record of the trace metal bioavailability at the location where the organism has been located.

In September 2013, a team of researchers from Arctic Research Centre and University of Manitoba spent one week collecting samples in the Nuuk Fjord. The aim was to investigate the potential of otoliths and mussel shells as recorders of potential future pollution from the proposed ISUA iron-mine and from Nuuk Harbor. The project was focused on shorthorn sculpins as a key species as it is considered relatively stationary, abundant and the otoliths are relatively easy and cost-effective to analyze (in contrast to mussel shells, which are much more time-consuming). In addition to sculpins, a few samples of cod and blue mussels were taken.

The results will show the potential of otoliths from sculpins for recording availability of specific elements in the Nuuk Fiord and will provide baseline knowledge prior to beginning of the proposed mining activities.

Lis Bach, Arctic Research Centre, Aarhus University
Anders Mosbech, Arctic Research Centre, Aarhus University
Norman Halden, University of Manitoba
Jens Søndergaard, Arctic Research Centre, Aarhus University

For more information, contact Jens Søndergaard