Dataset: Measurements of the dissolved isotope radium-226 from samples collected on the US GEOTRACES GP17-OCE cruise on R/V Roger Revelle (RR2214) in the South Pacific and Southern Oceans from December 2022 to January 2023

At sea, Radium-226 samples were collected following the GEOTRACES cookbook. Samples were collected from a 30-liter (L) Niskin mounted directly above a McLane large volume in situ pump WTS-LV (>1000 meters) or on the ODF CTD Rosette (<1000 meters). These samples (10-25 L) were recirculated through 20 grams (g) of manganese (Mn) oxide impregnated acrylic fiber at approximately <1 liter per minute (L/min) using small pumps. The Mn fibers from the Niskin bottles were rinsed with deionized water back at Woods Hole Oceanographic Institution (WHOI), partially dried, and sealed within a fiber holder after being flushed with helium equivalent to 30 column volumes. Samples were stored for a minimum of 12 days and analyzed for 226Ra via 222Rn ingrowth using alpha scintillation counting (Key et al., 1979). Samples were counted for 1-20 hours depending on the activity on the fiber, which resulted in counting uncertainties of ~2% dependent upon 226Ra content on the fiber and sample volume.