Trace metal clean sampling equipment was deployed on a sub-set of cruises to facilitate the observation of contamination prone chemical parameters. All trace metal sample collection, handling, and analysis was conducted in accordance with GEOTRACES protocols which have been updated through the SFB754 program (Cutter et al., 2014). For cruises with extensive trace metal work, the deployment of an over-pressured clean container on deck facilitated sampling and collection of trace metal and other contamination-prone samples at sea. For cruises from 2008 to 2013, PTFE-coated 8 l GO-FLO bottles (General Oceanics) were mounted on a Kevlar wire with sample handling and preservation as per Chever et al. (2015). From 2014 onwards, 24 Ocean Test Equipment (OTE) samplers were deployed mounted on a powder coated sampling CTD (Sea-Bird SBE25) rosette using a Kevlar conducting cable with sample handling and preservation as per Rapp et al. (2019).