Fig. 1. Settling particles: a low magnification photomicrograph of typical exported ocean particles intercepted by a mesopelagic TS-trap deployed in the carbonate ocean. A variety of zooplankton fecal pellets, several species of planktonic foraminifer tests, pteropod shells, large diatom frustules, and coccospheres are seen. Amorphous aggregates (marine snow flakes are loaded by coccoliths (not resolved under this low magnification). The fecal pellet at the mid-left of the photo is approximately 150 micrometer long. Biogeochemical investigation of the exported particles uses the mole values of the majority of elements from total export particles, POC, PIC (CaCO3) and Biogenic Si (SiO2).