Table 7.

Annual cellular production of prokaryotes in various habitats

Habitat	Population size	Turnover time, days	Cells/yr, × 1029
Marine heterotrophs
Above 200 m	3.6  ×  1028	16*	8.2
Below 200 m	8.2  ×  1028	300*	1.1
Marine autotrophs	2.9  ×  1027	1.5†	7.1
Soil	2.6  ×  1029	900*	1.0
Subsurface	4.9 × 1030*	5.5  ×  105*	0.03
Domestic mammals	4.3  ×  1024‡	1§	0.02

^*The value or mean of the range discussed in the text. 

^†Based on the median generation time of Prochlorococcus (84). 

^‡Sum of the number of prokaryotes in cattle, sheep, goats, and pigs from Table 4. 

^§From ref. 85.