• DOI:10.1073/pnas.0710279105
• Corpus ID: 8889134

Amazon River enhances diazotrophy and carbon sequestration in the tropical North Atlantic Ocean

@article{Subramaniam2008AmazonRE,
  title={Amazon River enhances diazotrophy and carbon sequestration in the tropical North Atlantic Ocean},
  author={Ajit Subramaniam and Patricia L. Yager and Edward J. Carpenter and Claire Mahaffey and Karin M. Bj{\"o}rkman and Sarah R. Cooley and Adam B Kustka and Joseph P. Montoya and Sergio A. Sa{\~n}udo-Wilhelmy and Rebecca F. Shipe and Douglas G. Capone},
  journal={Proceedings of the National Academy of Sciences},
  year={2008},
  volume={105},
  pages={10460 - 10465}
}

• A. Subramaniam, P. Yager, +8 authors D. Capone
• Published 29 July 2008
• Environmental Science
• Proceedings of the National Academy of Sciences

The fresh water discharged by large rivers such as the Amazon is transported hundreds to thousands of kilometers away from the coast by surface plumes. The nutrients delivered by these river plumes contribute to enhanced primary production in the ocean, and the sinking flux of this new production results in carbon sequestration. Here, we report that the Amazon River plume supports N2 fixation far from the mouth and provides important pathways for sequestration of atmospheric CO2 in the western tropical North Atlantic (WTNA). We calculate that the sinking of carbon fixed by diazotrophs in the plume sequesters 1.7 Tmol of C annually, in addition to the sequestration of 0.6 Tmol of C yr−1 of the new production supported by NO3 delivered by the river. These processes revise our current understanding that the tropical North Atlantic is a source of 2.5 Tmol of C to the atmosphere [Mikaloff-Fletcher SE, et al. (2007) Inverse estimates of the oceanic sources and sinks of natural CO2 and the implied oceanic carbon transport. Global Biogeochem Cycles 21, doi:10.1029/2006GB002751]. The enhancement of N2 fixation and consequent C sequestration by tropical rivers appears to be a global phenomenon that is likely to be influenced by anthropogenic activity and climate change.