RESUMEN
Sediment samples (0-1 cm) and tube-dwelling polychaetes from the Norwegian Continental Shelf and the Barents Sea were collected, including areas close to oil and gas installations and remote locations. Microplastics (≥45 µm) were found in quantifiable levels in 27 of 35 sediment samples, from 0.039 to 3.4 particles/gdw (dw = dry weight); and in 9 of 10 pooled polychaete samples, from 11 to 880 particles/gww (ww = wet weight). Concentrations were significantly higher in tube-dwelling polychaetes than sediments from the same locations (p<0.0097) by orders of magnitude. To quantify this factor increase in polychaetes, a Biota-Sediment Particle Enrichment Factor (BSPEF) is introduced, which ranged from 100 to 11000 gdw/gww (280-31000 gdw/gdw). Higher microplastic levels were observed in polychaete tube than in soft tissue (n=4). The feeding behavior and life cycle of tube-dwelling polychaetes could have an important influence on the transport, distribution and food-chain dynamics of microplastics on the seafloor.