Dataset: Size Fractionated Particulate Thorium-234 measurements collected during the 2012-2013 Palmer Field Season

Particulate organic carbon, nitrogen, and ²³⁴Th associated with >50-µm particles was measured at depths from the surface to 30 m at Station E near Palmer Station.  Samples were collected using two different methods.  For surface sampling, 20-L carboys were filled with surface seawater and gently poured through a 50-µm sieve.  For samples from depth, water was pumped to the surface using a Monsoon pump and filtered through a 50-µm sieve.  Volumes filtered varied depending on particle load but were typically between 50 and 100 L.  Sieves were rinsed onto pre-combusted glass fiber (GF/F) filters.  Filters were dried and mounted in RISO planchets.  Samples were then counted in a RISO low-level beta multi-counter to determine activity of ²³⁴Th. Background counts were conducted >6 half-lives after collection.  Samples were then acidified to remove CaCO₃ and analyzed in an elemental analyzer to determine particulate organic carbon and particulate nitrogen on filters.  For additional details, see Stukel et al. (2022).