Table 3 Chemoautotrophic growth rate, uptake, and chemosynthate release fluxes of C (Tg year−1) and P (Gg year−1) in the global ocean.

Estimates are based on measured ratios of N. maritimus NAOA6 fluxes of C and P relative to nitrite production during radiotracer experiments (Table 1 and fig. S5) and respiration rates of organic C in the euphotic or dark oceans [after (2, 31); see text S1]. In the euphotic zone, the fluxes correspond to the proportion of reduced N from respiration that is assumed to be available for nitrification [43%, after (2, 12)]. The range of total C or P fluxes in the dark ocean corresponds to the low and high estimates of total N mineralization flux (92 or 330 Tmol N year−1; see text). Relatively lower C and P uptake fluxes observed in response to P limitation are accounted for by assuming 13% of the open ocean euphotic zone is P limited [i.e., the N. Atlantic Equatorial and Subtropical Gyre; 15°S to 45°N; (13)]. Thaumarchaeal growth rates (day−1) are estimated on the basis of population densities reported by (11), ocean surface areas (31) and depths of hypsometric regions (43), C content of 12.9 fg cell−1 (22), and the C fixation fluxes reported here for each region.

ZoneFluxNear-shoreShelfSlopeOpenTotal
EuphoticGrowth rate
(day−1)
0.4130.2090.0810.049
C fixation
(Tg year−1)
483960676824
P uptake
(Gg year−1)
1.21.01.416.920
DOC release
(Tg year−1)
2.11.72.630.437
DOP release
(Gg year−1)
0.0080.0060.0100.1060.13
DarkGrowth rate
(day−1)
nd0.0990.0060.002
C fixation
(Tg year−1)
1.81529284330–1190
P uptake
(Gg year−1)
0.040.370.706.78–29
DOC release
(Tg year−1)
0.080.661.2412.114–51
DOP release
(Gg year−1)
0.00030.0030.0050.0460.05–0.19