Life

A trillion species or kinds of bacterial on Earth.

Locey, Kenneth J., and Jay T. Lennon. “Scaling Laws Predict Global Microbial Diversity.” Proceedings of the National Academy of Sciences 113, no. 21 (2016): 5970–75. https://doi.org/10/f8qmmd.

The continental subsurface hosts $2~to~6 × 10^{29}$ cells.

Magnabosco, Cara, L.-H. Lin, H. Dong, M. Bomberg, W. Ghiorse, H. Stan-Lotter, K. Pedersen, T. L. Kieft, E. van Heerden, and T. C. Onstott. “The Biomass and Biodiversity of the Continental Subsurface.” Nature Geoscience 11, no. 10 (2018): 707–17. https://doi.org/10/gd8fkc.

A single generation of some crust organisms can take 1000 to 10,000,000 years.

The Biome Deep, Deep Beneath Everything | Applied Ecology | NC State University (ncsu.edu)

Inagaki, F., K.-U. Hinrichs, Y. Kubo, M. W. Bowles, V. B. Heuer, W.-L. Hong, T. Hoshino, et al. “Exploring Deep Microbial Life in Coal-Bearing Sediment down to ~2.5 Km Below the Ocean Floor.” Science 349, no. 6246 (2015): 420–24. https://doi.org/10/f7kc3c.