Total water-column Thorium-234 was determined by following the methods of Pike, et al. (2005) and Clevenger, et al. (2021) on 2-liter (L) water column samples, as mentioned in International GEOTRACES cookbook. An exact 1-milliliter (mL) aliquot of 230Th (50.03 disintegrations per minute per gram (dpm g⁻¹)) was used as the yield monitor and added during initial acidification of the samples. QMAs were used to collect the precipitate from the 2 L process and immediately dried. Once dried, they were mounted onto plastic 25-millimeter (mm) discs, covered with a mylar layer and two layers of aluminum foil, and immediately beta counted at sea. The filters were counted again, 5 to 6 months later to quantify the background radioactivity due to the beta decay of long-lived natural radionuclides that are also precipitated. The mean value of the at-sea counts (decay-corrected to the time of collection) minus the background value for each filter is reported as the 234Th activity (dpm L⁻¹). Activities for 234Th are generally reported in disintegrations per minute per liter (dpm L⁻¹). Data are decay-corrected to the mid-point time between when the first and last bottles were fired for shallow casts, when the messenger was dropped for deep casts, and the time of collection for fish tow samples. All data have been recovery-corrected using the 230Th /229Th recovery method (see References) to account for any loss of sample material during processing. All samples were analyzed using Risø Laboratory Anti-Coincidence Beta Counters, using a helium/1% butane mixture. Uranium-238 is calculated as a function of salinity described in Owens et al., 2011.