The oceanic carbon cycle is mainly determined by the combined activities of bacteria and phytoplankton1,2, but the interdependence of climate, the carbon cycle and the microbes is not well understood. To elucidate this interdependence, we performed high-frequency sampling of sea water along a north–south transect of the Atlantic Ocean. Here we report that the interaction of bacteria and phytoplankton is closely related to the meridional profile of water temperature, a variable directly dependent on climate. Water temperature was positively correlated with the ratio of bacterial production to primary production, and, more strongly, with the ratio of bacterial carbon demand to primary production. In warm latitudes (25° N to 30° S), we observed alternating patches of predominantly heterotrophic and autotrophic community metabolism. The calculated regression lines (for data north and south of the Equator) between temperature and the ratio of bacterial production to primary production give a maximum value for this ratio of 40% in the oligotrophic equatorial regions. Taking into account a bacterial growth efficiency3,4 of 30%, the resulting area of net heterotrophy (where the bacterial carbon demand for growth plus respiration exceeds phytoplankton carbon fixation4,5,6) expands from 8° N (27 °C) to 20° S (23 °C). This suggests an output of CO2 from parts of the ocean to the atmosphere6,7.
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Azam, F. Microbial control of oceanic carbon flux: The plot thickens. Science 280, 694–696 (1998).
Ducklow, H. W. The bacterial component of the oceanic euphotic zone. FEMS Microb. Ecol. 30, 1–10 (1999).
Amon, R. M. W. & Benner, R. Rapid cycling of high-molecular-weight dissolved organic matter in the ocean. Nature 369, 549–552 (1994).
del Giorgio, P. A., Cole, J. J. & Cimbleris, A. Respiration rates of bacteria exceed phytoplankton production in unproductive aquatic systems. Nature 385, 148–151 (1997).
Sorokin, Y. I. Bacterial populations as components of oceanic ecosystems. Mar. Biol. 11, 101–105 (1971).
Duarte, C. M. & Agusti, S. The CO2 balance of unproductive aquatic ecosystems. Science 281, 234–236 (1998).
Azam, F., Steward, G. F. & Ducklow, H. W. Significance of bacteria in carbon fluxes in the Arabian Sea. Proc. Ind. Acad. Sci. 103, 341–351 (1994).
Simon, M., Cho, B. C. & Azam, F. Significance of bacterial biomass in lakes and the ocean: comparison to phytoplankton biomass and biogeochemical implications. Mar. Ecol. Prog. Ser. 86, 103–110 (1992).
Azam, F. et al. The ecological role of water-column microbes in the sea. Mar. Ecol. Prog. Ser. 10, 257–263 (1983).
Duarte, C. M., Agustí, S., Arístegui, J., Gonzáles, N. & Anadón, R. Evidence for a heterotrophic subtropical northeast Atlantic. Limnol. Oceanogr. 46, 425–428 (2001).
Rivkin, R. B. & Legendre, L. Biogenic carbon cycling in the upper ocean: Effects of microbial respiration. Science 291, 2398–2400 (2001).
Longhurst, A. Ecological Geography of the Ocean (Academic, London, 1998).
Zubkov, M. V., Sleight, M. A. & Burkill, P. H. Heterotrophic bacterial turnover along the 20°W meridian between 59°N and 37°N in July 1996. Deep-Sea Res. II 48, 987–1001 (2001).
Lochte, K., Bjønsen, P. K., Giesenhagen, H. & Weber, A. Bacterial standing stock and production and their relation to phytoplankton in the Southern Ocean. Deep-Sea Res. II 44, 321–340 (1997).
Bird, D. F. & Kalff, J. Empirical relationship between bacterial abundance and chlorophyll concentration in fresh and marine waters. Can. J. Fish. Aquat. Sci. 41, 1015–1023 (1984).
Cole, J. J., Pace, M. L. & Findlay, S. Bacterial production in fresh and saltwater ecosystems: a cross-system overview. Mar. Ecol. Prog. Ser. 43, 1–10 (1988).
Hurtt, G. C. & Armstrong, R. A. A pelagic ecosystem model calibrated with BATS data. Deep-Sea Res. II 43, 653–683 (1996).
Fasham, M. J. R., Boyd, P. W. & Savidge, G. Modelling the relative contributions of autotrophs and heterotrophs to carbon flow at a Lagrangian JGOFS station in the Northeast Atlantic. Limnol. Oceanogr. 44, 80–94 (1999).
Kirchman, D. L., Rich, J. H. & Barber, R. T. Biomass and biomass production of heterotrophic bacteria along 140 W in the equatorial Pacific: effect of temperature on the microbial loop. Deep-Sea Res. II 42, 603–619 (1995).
Karrasch, B., Hoppe, H.-G., Ullrich, S. & Podewski, S. The role of mesoscale hydrography on microbial dynamics in the northeast Atlantic: Results of a spring bloom experiment. J. Mar. Res. 54, 99–122 (1996).
Rivkin, R. B., Anderson, M. R. & Lajzerowicz, C. Microbial processes in cold oceans. 1. Relationship between temperature and bacterial growth rate. Aquat. Microb. Ecol. 10, 243–254 (1996).
Geider, R. J. Photosynthesis or planktonic respiration? Nature 388, 132 (1997).
Williams, P. J. le B. The balance of plankton respiration and photosynthesis in the open oceans. Nature 394, 55–57 (1998).
Williams, P. J. le B. & Bower, D. G. Regional carbon imbalances in the oceans. Science 284, 1735 (1999).
Kuipers, B., van Noort, G. J., Vosjan, J. & Herndl, G. J. Diel periodicity of bacterioplankton in the euphotic zone of the subtropical Atlantic Ocean. Mar. Ecol. Prog. Ser. 201, 13–25 (2000).
Raymond, P. A. & Bauer, J. E. Riverine export of aged terrestrial organic matter to the North Atlantic Ocean. Nature 409, 497–500 (2001).
Fuhrman, J. A. & Azam, F. Thymidine incorporation as a measure of heterotrophic bacterioplankton production in marine surface waters: Evaluation and field results. Mar. Biol. 66, 109–120 (1982).
Simon, M. & Azam, F. Protein content and protein synthesis rates of planktonic marine bacteria. Mar. Ecol. Prog. Ser. 51, 201–213 (1989).
Hoppe, H.-G. in Current Methods in Aquatic Microbial Ecology (eds Kemp, P. F., Sherr, B. F., Sherr, E. B. & Cole, J. J.) 423–431 (CRC, Boca Raton, 1993).
We thank K. Lochte and K. Jürgens for discussions, and Rory P. Wilson for linguistic corrections. We thank DFG and BMBF for support of our JGOFS programmes.
The authors declare no competing financial interests.
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Hoppe, H., Gocke, K., Koppe, R. et al. Bacterial growth and primary production along a north–south transect of the Atlantic Ocean. Nature 416, 168–171 (2002). https://doi.org/10.1038/416168a
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