Letter | Published:

Riverine export of aged terrestrial organic matter to the North Atlantic Ocean

Nature volume 409, pages 497500 (25 January 2001) | Download Citation

Subjects

Abstract

Global riverine discharge of organic matter represents a substantial source of terrestrial dissolved and particulate organic carbon to the oceans1,2. This input from rivers is, by itself, more than large enough to account for the apparent steady-state replacement times of 4,00–6,000 yr for oceanic dissolved organic carbon3,4,5. But paradoxically, terrestrial organic matter, derived from land plants, is not detected in seawater and sediments in quantities that correspond to its inputs6,7,8. Here we present natural 14C and 13C data from four rivers that discharge to the western North Atlantic Ocean and find that these rivers are sources of old (14C-depleted) and young (14C-enriched) terrestrial dissolved organic carbon, and of predominantly old terrestrial particulate organic carbon. These findings contrast with limited earlier data9 that suggested terrestrial organic matter transported by rivers might be generally enriched in 14C from nuclear testing, and hence newly produced. We also find that much of the young dissolved organic carbon can be selectively degraded over the residence times of river and coastal waters, leaving an even older and more refractory component for oceanic export. Thus, pre-ageing and degradation may alter significantly the structure, distributions and quantities of terrestrial organic matter before its delivery to the oceans.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    , & What happens to terrestrial organic matter in the ocean? Org. Geochem. 27, 195–212 (1997).

  2. 2.

    Riverine transport of atmospheric carbon: sources, global typology, and budget. Wat. Air Soil Pollut. 70, 443–463 (1993).

  3. 3.

    , & 14C activity of dissolved organic carbon fractions in the North Central Pacific and Sargasso Sea. Nature 357, 667–670 (1992).

  4. 4.

    , , & Cycling of dissolved and particulate organic matter in the open ocean. J. Geophys. Res. 97, 15639–15659 (1992).

  5. 5.

    & Radiocarbon in dissolved organic carbon in the central north Pacific Ocean. Nature 330, 246–248 (1987).

  6. 6.

    & Molecular evidence for a terrestrial component of organic matter dissolved in ocean water. Nature 321, 61–63 (1986).

  7. 7.

    , , & A comparison of dissolved humic substances from seawater with Amazon River counterparts by 13C-NMR spectrometry. Geochim. Cosmochim. Acta 56, 1753–1757 (1992).

  8. 8.

    & Distribution and cycling of terrigenous dissolved organic matter in the ocean. Nature 386, 480–482 (1997).

  9. 9.

    et al. Organic carbon-14 in the Amazon River system. Science 231,1129–1131 (1986).

  10. 10.

    in Flux of Organic Carbon by Rivers to the Oceans 79–109 (Report CONF-8009140, US Dept of Energy, Springfield, 1981).

  11. 11.

    & Particulate organic carbon export from a subtropical mountainous river (Lanyang Hsi) in Taiwan. Limnol. Oceanogr. 41, 1749–1757 (1996).

  12. 12.

    & Twenty years of atmospheric 14CO2 observations at Schauinsland station, Germany. Radiocarbon 39, 205–218 (1997).

  13. 13.

    et al. Composition and fluxes of particulate organic material in the Amazon River. Limnol. Oceanogr. 31, 717–738 (1986).

  14. 14.

    , & Predicting the oceanic input of organic carbon by continental erosion. Glob. Biogeochem. Cycles 10, 23–41 (1996).

  15. 15.

    , , & Rapid accumulation and turnover of soil carbon in a re-establishing forest. Nature 400, 56–58 (1999).

  16. 16.

    , & in Flux of Organic Carbon by Rivers to the Oceans 46–75 (Report CONF-8009140, US Dept of Energy, Springfield, 1981).

  17. 17.

    , & AMS 14C measurements of fractionated soil organic matter: An approach to deciphering the soil carbon cycle. Radiocarbon 31, 644–654 (1989).

  18. 18.

    , , & Sources and transformation of dissolved organic carbon in the Harp Lake forested catchment: The role of soils. Radiocarbon 34, 636–635 (1992).

  19. 19.

    in Perspectives on Biogeochemistry (ed. Degens, E. T.) Ch. 11, 303–304 (Springer, New York, 1989).

  20. 20.

    & Oceanographic and geologic framework of the Hudson system. Northeast. Geol. 8, 96–108 (1986).

  21. 21.

    & Geochemistry of the Amazon 2. The influence of geology and weathering environment on the dissolved load. J. Geophys. Res. 88, 9671–9688 (1983).

  22. 22.

    , , , & Storage and remobilization of suspended sediment in the lower Amazon River of Brazil. Science 228, 488–490 (1985).

  23. 23.

    , , & Organic carbon spiralling in stream ecosystems. Oikos 38, 266–272 (1982).

  24. 24.

    & Sedimentary organic matter preservation: an assessment and speculative synthesis. Mar. Chem. 49, 81–115 (1995).

  25. 25.

    , , , & Loss of organic matter from riverine particles in deltas. Geochim. Cosmochim. Acta 61, 1507–1511 (1997).

  26. 26.

    , & Inputs of sediment and carbon to an estuarine ecosystem: influence of land use. Ecol. Appl. 1, 27–39 (1991).

  27. 27.

    & Bacterial consumption of DOC during transport through a temperate estuary. Aquat. Microb. Ecol. 22, 1–12 (2000).

  28. 28.

    , & Biodegradation of riverine dissolved organic carbon in five estuaries of the Southeastern United States. Estuaries 22, 55–64 (1999).

  29. 29.

    et al. Regional nitrogen budgets and riverine N & P fluxes for the drainages to the North Atlantic Ocean; Natural and human influences. Biogeochemistry 35, 75–139 (1996).

  30. 30.

    , & Catalyst and binder effects in the use of filamentous graphite for AMS. Nucl. Instrum. Methods Phys. Res. B 29, 50–56 (1987).

  31. 31.

    & Discussion: reporting of 14C data. Radiocarbon 19, 355–363 (1977).

  32. 32.

    Preparation of carbon dioxide for stable carbon isotope analysis of petroleum fractions. Anal. Chem. 52, 1389–1391 (1980).

Download references

Acknowledgements

We thank J. Cole, N. Caraco and C. Hopkinson for help in collecting samples from the Hudson and Parker rivers; D. Wolgast for assistance in oxidizing DOC samples; M. Kashgarian, J. Southon and B. Frantz for 14C analyses at the Center for AMS at Lawrence Livermore National Laboratory (LLNL); E. Druffel and S. Griffin for analysing the Amazon POC sample; J. Hobbie for comments on the manuscript; and E. Franks for δ13C analyses at Woods Hole Oceanographic Institution. This work was supported by the Ocean Margins Program of the US Department of Energy, the Chemical Oceanography and Long-Term Ecological Research Programs of the US NSF, and the Center for AMS at LLNL.

Author information

Author notes

    • Peter A. Raymond

    Present address: Marine Biological Laboratory, Ecosystems Center, Woods Hole, Massachusetts 02543, USA

Affiliations

  1. *School of Marine Science, College of William and Mary, Gloucester Point, Virginia 23062, USA

    • Peter A. Raymond
    •  & James E. Bauer

Authors

  1. Search for Peter A. Raymond in:

  2. Search for James E. Bauer in:

Corresponding author

Correspondence to Peter A. Raymond.

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/35054034

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.