While most of the flux in oceanic areas is of biological origin, most of it is not
organic matter as such; biological minerals are dominant. About three-quarters of the
mass flux in typical PARFLUX profiles is calcium carbonate: coccoliths,
foraminiferan shells, and pteropod shells. Opal (solid, polymerized Si(OH) 4 : diatoms,
silicoflagellates, radiolarians) is another one-eighth or a little more, and carbon in
organic matter is about 8%. The remainder is the other elements in organic matter and
“lithogenic” particles (mostly clay). The ratio of calcium carbonate to organics
increases significantly downward, to at least 1000 m. Mineral content in sinking
agglomerations is important as ballast, accelerating the particles to speeds >100 m d
−1.