Table 7

Annual cellular production of prokaryotes in various habitats

HabitatPopulation sizeTurnover time, daysCells/yr, × 1029
Marine heterotrophs
 Above 200 m3.6  ×  1028 16*8.2
 Below 200 m8.2  ×  1028300*1.1
Marine autotrophs2.9  ×  10271.57.1
Soil2.6  ×  1029900*1.0
Subsurface4.9 × 1030*5.5  ×  105*0.03
Domestic mammals4.3  ×  10241§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