Dataset: Silicon stable isotopes for samples collected from surface to depth on the US GEOTRACES GP17-OCE cruise on R/V Roger Revelle (RR2214) from December 2022 to January 2023

Sampling of silicon (Si) isotopes followed GEOTRACES sampling protocols for Si isotopes (Cutter et al., 2010). Seawater (0.5 to 2 liters (L)) was collected using the conventional CTD rosette. Seawater was filtered directly from Niskin bottles through silicone tubing plumbed with an inline Acropak filter cartridge (0.8/0.45 micrometer (μm) Supor filter) into acid-cleaned polyethylene bottles. This protocol was used for Si isotopes on previous GEOTRACES cruises. Filtered samples are stored at ambient temperature in the dark and shipped to UCSB for processing.

Silicon preparations were analyzed at UCSB using a Nu Perspective IRMS with a NuSil sample introduction system, following the methods of Brzezinski, et al. (2025). See the Supplemental Files for additional information describing methods.