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Annual flux of dissolved organic carbon from the euphotic zone in the northwestern Sargasso Sea


THE export of biogenic carbon from the upper ocean is responsible for maintaining the vertical gradient of dissolved inorganic carbon and thus indirectly for regulating the level of atmospheric CO2 (ref. 1). Large, rapidly sinking particles are thought to dominate this export2, and this sinking flux has been thought to balance new production3. Recent measurements of particle export4—6 and estimates of new production7—9 have questioned this picture, however. Here we report measurements of dissolved organic carbon (DOC) off Bermuda, which provide strong support for the idea10—15 that this component of oceanic carbon is also an important and dynamic part of the ocean carbon cycle. We find that DOC accumulates in the early spring owing to increased primary production, and is partially consumed in the summer and autumn. The DOC that escapes remineralization is exported from the surface ocean the following winter, and we estimate this export to be equal to or greater than the measured particle flux, allowing us to close the annual vertical carbon budget for this site to within a factor of two. Our observations should be applicable to other temperate, sub-polar and continental-shelf regions of the world ocean which exhibit convective mixing and vernal restratification.

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  1. 1

    Sarmiento, J. L. & Siegenthaler, U. in Primary Productivity and Biogeochemical Cycles in the Sea (eds Falkowski, P. G. & Woodhead, A. D.) 317–332 (Plenum, New York, 1992).

    Book  Google Scholar 

  2. 2

    McCave, I. N. Deep-Sea Res. 22, 491–502 (1975).

    Google Scholar 

  3. 3

    Eppley, R. W. & Peterson, B. J. Nature 282, 677–680 (1979).

    ADS  Article  Google Scholar 

  4. 4

    Altabet, M. A. J. geophys. Res. 94, 12771–12779 (1989).

    ADS  CAS  Article  Google Scholar 

  5. 5

    Lohrenz, S. E. et al. Deep-Sea Res. 39, 1373–1391 (1992).

    ADS  CAS  Article  Google Scholar 

  6. 6

    Michaels, A. F. et al. Deep-Sea Res. 41, 1013–1038 (1994).

    CAS  Article  Google Scholar 

  7. 7

    Jenkins, W. J. & Goldman, J. C. J. Mar. Res. 43, 465–491 (1985).

    CAS  Article  Google Scholar 

  8. 8

    Jenkins, W. J. Nature 331, 521–523 (1988).

    ADS  CAS  Article  Google Scholar 

  9. 9

    Spitzer, W. S. & Jenkins, W. J. J. mar. Res. 47, 169–196 (1989).

    CAS  Article  Google Scholar 

  10. 10

    Copin-Montégut, G. & Avril, B. Deep-Sea Res. 40, 1963–1972 (1993).

    Article  Google Scholar 

  11. 11

    Toggweiler, J. R. in Productivity of the Ocean: Present and Past (eds Berger, W. H., Smetacek, V. S. & Wefer, G.) 65–83 (Wiley, Dahlem Donferenzen, Germany, 1989).

    Google Scholar 

  12. 12

    Bacastow, R. & Maier-Reimer, E. Globl Biogeochem. Cycles 5, 71–85 (1991).

    ADS  CAS  Article  Google Scholar 

  13. 13

    Najjar, R. G., Sarmiento, J. L. & Toggweiler, J. R. Globl Biogeochem. Cycles 6, 45–76 (1992).

    ADS  CAS  Article  Google Scholar 

  14. 14

    Suzuki, Y., Sugimura, Y. & Itoh, T. Mar. Chem. 16, 83–97 (1985).

    CAS  Article  Google Scholar 

  15. 15

    Goldman, J. C., Hansell, D. A. & Dennett, M. R. Mar. Ecol. Prog. Ser. 88, 257–270 (1992).

    ADS  CAS  Article  Google Scholar 

  16. 16

    Sugimura, Y. & Suzuki, Y. Mar. Chem. 24, 105–131 (1988).

    CAS  Article  Google Scholar 

  17. 17

    Suzuki, Y. Mar. Chem. 41, 287–288 (1993).

    Article  Google Scholar 

  18. 18

    Sharp, J. H. et al. Limnol. Oceanogr. 38, 1774–1782 (1993).

    ADS  CAS  Article  Google Scholar 

  19. 19

    Hansell, D. A., Williams, P. M. & Ward, B. B. Deep Sea Res. 40, 219–234 (1993).

    CAS  Article  Google Scholar 

  20. 20

    Sharp, J. H. et al. Mar. Chem. (in the press).

  21. 21

    Peltzer, E. T. & Brewer, P. G. Mar. Chem. 41, 243–252 (1993).

    CAS  Article  Google Scholar 

  22. 22

    Benner, R. & Strom, M. Mar. Chem. 41, 153–160 (1993).

    CAS  Article  Google Scholar 

  23. 23

    Menzel, D. W. & Ryther, J. H. Deep-Sea Res. 6, 351–367 (1960).

    ADS  Google Scholar 

  24. 24

    Malone, T. C., Pike, S. E. & Conley, D. J. Deep-Sea Res. 40, 903–924 (1993).

    Article  Google Scholar 

  25. 25

    Bauer, J. E., Williams, P. M. & Druffel, E. R. M. Nature 357, 667–670 (1992).

    ADS  CAS  Article  Google Scholar 

  26. 26

    Duursma, E. K. Neth. J. Sea Res. 1, 1–148 (1961).

    Article  Google Scholar 

  27. 27

    Siegel, D. A. et al. J. mar. Res. 48, 379–412 (1990).

    CAS  Article  Google Scholar 

  28. 28

    Michaels, A., Buesseler, K., Bates, N., Carlson, C. A. & Knap, A. Nature (submitted).

  29. 29

    Sarmiento, J. L., Thiele, G., Key, R. M. & Moore, W. S. J. geophys. Res. 95, 18303–18315 (1990).

    ADS  CAS  Article  Google Scholar 

  30. 30

    Martin, J. H., Knauer, G. A., Karl, D. M. & Broenkow, W. W. Deep-Sea Res. 34, 127–143 (1987).

    Article  Google Scholar 

  31. 31

    Carlson, C. A. & Ducklow, H. W. Deep-Sea Res. (in the press).

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Carlson, C., Ducklow, H. & Michaels, A. Annual flux of dissolved organic carbon from the euphotic zone in the northwestern Sargasso Sea. Nature 371, 405–408 (1994).

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