Biological activity
Organisms are ubiquitous in surface waters; many have tests (shells or hard parts)
Organisms consume chemical constituents to make tests
After organisms die, their tests sink
- Some sinking tests dissolve (remember CCD)
- Others accumulate as oozes at the bottom of the ocean
- Have calcareous & siliceous oozes
- Remove 1-2 x 109 tons of Si+4, Ca +2, & CO3-2 as CaCO3 & SiO2