Hidden aliens: Application of digital PCR to track an exotic foraminifer across the Skagerrak (North Sea) correlates well with traditional morphospecies analysis.

The problem of invasive species is a well-studied one, but knowledge of free-living unicellular eukaryotic invasive species is lacking. A potentially invasive foraminifer (Rhizaria), Nonionella sp. T1, was recently discovered in the Skagerrak and its fjords.