The data and the (cleaned) R code used to produce this analysis are available from the NHM Data Portal:
https://doi.org/10.5519/0001936

Publication:
Rillo MC, Kucera M, Ezard THG and Miller CG (2019) Surface Sediment Samples From Early Age of Seafloor Exploration Can Provide a Late 19th Century Baseline of the Marine Environment. Front. Mar. Sci. 5:517. DOI: https://doi.org/10.3389/fmars.2018.00517