Total Th data from samples collected on 5 cruises at Station ALOHA off Hawaii and Station M off California from 2019 to 2020

The abyssal plains of the oceans cover roughly half of the earth's surface, host enormous reservoirs of biodiversity and mineral resources, and play important roles in nutrient regeneration and carbon sequestration. The most important process controlling the structure and function of these ecosystems is the quantity and quality of food (mostly sinking organic particles) that reaches the deep-sea floor. The goals of this research were to evaluate the relative importance of small and large particles that sink to the deep-sea using the naturally occurring short-lived radionuclide, 234Th. Particulate and dissolved samples were collected throughout the water column (12-17 depths) during 5 cruises in the productive waters off of California (Station M, May and October 2019) within the nutrient-poor central Pacific, north of Hawaii (Station ALOHA, July 2019 and January and July 2020). Total water column (2 L) and particulate 234Th activities collected using in situ pumps (53 um, 1 um, and 0.3 um) have been measured in all of the samples collected from the 5 cruises: April 2019, July 2019, October 2019, January 2020, and July 2020. This dataset includes the Total Th measurements. Particulate Th is available in a separate, related dataset.