Erosion of organic carbon from the Andes and its affects on ecosystem carbon dioxide balance
Clark, K.E.; Hilton, R.G.; West, A.J.; Robles Caceres, A.; Grocke, D.R.; Marthews, T.R.; Ferguson, R.I.; Asner, G.P.; New, M.; Malhi, Y.
A. Robles Caceres
Professor Darren Grocke firstname.lastname@example.org
Productive forests of the Andes are subject to high erosion rates that supply to the Amazon River sediment and carbon from both recently photosynthesized biomass and geological sources. Despite this recognition, the source and discharge of particulate organic carbon (POC) in Andean rivers remains poorly constrained. We collected suspended sediments from the Kosñipata River, Peru, over one year at two river gauging stations. Carbon isotopes (14C, 13C, 12C) and nitrogen to organic carbon ratios of the suspended sediments suggest a mixture of POC from sedimentary rocks (POCpetro) and from the terrestrial biosphere (POCbiosphere). The majority of the POCbiosphere has a composition similar to surface soil horizons and we estimate is mostly younger than 850 14C years. The suspended sediment yield in 2010 was 3500 ± 210 t km-2 yr-1, >10 times the yield from the Amazon Basin. The POCbiosphere yield was 12.6 ± 0.4 tC km-2 yr-1 and the POCpetro yield was 16.1 ± 1.4 tC km-2 yr-1, mostly discharged in the wet season (December to March) during flood events. The river POCbiosphere discharge is large enough to play a role in determining whether Andean forests are a source or sink of carbon dioxide. The estimated erosional discharge of POCpetro from the Andes is much larger (~1 Mt C yr-1) than the POCpetro discharge by the Madeira River downstream in the Amazon Basin, suggesting oxidation of POCpetro counters CO2 drawdown by silicate weathering. The flux and fate of Andean POCbiosphere and POCpetro needs to be better constrained to fully understand the carbon budget of the Amazon River Basin.
Clark, K., Hilton, R., West, A., Robles Caceres, A., Grocke, D., Marthews, T., …Malhi, Y. (2017). Erosion of organic carbon from the Andes and its affects on ecosystem carbon dioxide balance. Journal of Geophysical Research: Biogeosciences, 122(3), 449-469. https://doi.org/10.1002/2016jg003615
|Journal Article Type||Article|
|Acceptance Date||Jan 16, 2017|
|Online Publication Date||Mar 6, 2017|
|Publication Date||Mar 6, 2017|
|Deposit Date||Feb 17, 2017|
|Publicly Available Date||Sep 6, 2017|
|Journal||Journal of Geophysical Research: Biogeosciences|
|Publisher||American Geophysical Union|
|Peer Reviewed||Peer Reviewed|
Published Journal Article (Advance online version)
Advance online version Clark, K.E., Hilton, R.G., West, A.J., Robles Caceres, A., Grocke, D.R., Marthews, T.R., Ferguson, R.I., Asner, G.P., New, M. & Malhi, Y. (2017). Erosion of organic carbon from the Andes and its affects on ecosystem carbon dioxide balance. Journal of Geophysical Research - Biogeosciences. 122(3): 449-469, DOI: 10.1002/2016JG003615. To view the published open abstract, go to https://doi.org/ and enter the DOI.
Published Journal Article (Final published version)
Final published version
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