Insights into particle formation and remineralization using the short-lived radionuclide, Thoruim-234
Article first published online: 14 AUG 2010
Copyright 2010 by the American Geophysical Union.
Geophysical Research Letters
Volume 37, Issue 15, August 2010
How to Cite
2010), Insights into particle formation and remineralization using the short-lived radionuclide, Thoruim-234, Geophys. Res. Lett., 37, L15608, doi:10.1029/2010GL044063., , and (
- Issue published online: 14 AUG 2010
- Article first published online: 14 AUG 2010
- Manuscript Accepted: 30 JUN 2010
- Manuscript Revised: 16 JUN 2010
- Manuscript Received: 20 MAY 2010
- particle export;
 Simple mass balance models are applied to a high resolution 234Th profile from the northwest Pacific to examine the magnitude, rate, and depth distribution of particle remineralization processes below the euphotic zone (Ez). Here, excess 234Th (234Th > 238U) below the Ez is attributed to fragmentation processes that result in the conversion of sinking to non-sinking particles. By considering particulate organic carbon (POC) to 234Th ratios on particles, we show that POC flux attenuation is larger than for 234Th, which we attribute to bacterial and zooplankton consumption of sinking POC. Three case studies are used to demonstrate how different combinations of particle fragmentation and POC respiration impact flux attenuation below the Ez. When sampled with high vertical resolution and precision, 234Th and POC/234Th ratios provide insights into both export from the Ez and the extent to which sinking particle fluxes and associated minerals are attenuated with depth.