The dataset contains polychaete abundance data collected from boxcores samples (BC; 0.25 m2) collected in the eastern Clarion Clipperton fracture Zone (northeast Pacific), an area currently being explored for polymetallic nodules. Macrobenthic samples were collected onboard RV Sonne during expedition SO239 in 2015. Four exploration contract areas (BGR, IOM, GSR and Ifremer) and one “Area of Particular Environmental Interest” (APEI#3) were sampled. Between 3 and 8 quantitative box cores were collected in each area. Boxcore samples were sliced in three layers (0-3, 3-5 and 5-10 cm depth) and sieved on a 300 µm mesh. Polychaetes have been counted, sequenced and identified. Identifications were realised based on morphology and DNA (COI, 16S and 18S genes) leading to morphotype in most cases (species-level). DNA sequences are available in Genbank or BOLD databases with their respective codes in this dataset.

• Comment Species Level: 'TRUE': The specimen has been identified down to species or putative species level; "FALSE": The specimen has been identified at a taxonomic resolution lower than species

Supplement to: Bonifácio, Paulo; Martínez Arbizu, Pedro; Menot, Lenaick (2020): Alpha and beta diversity patterns of polychaete assemblages across the nodule province of the eastern Clarion-Clipperton Fracture Zone (equatorial Pacific). Biogeosciences, 17(4), 865-886