Fluvial carbon export from a lowland Amazonian rainforest in relation to atmospheric fluxes
Date
2016
Authors
Vihermaa, Leena E.
Waldron, Susan
Domingues, Tomas
Grace, John
Cosio, Eric G.
Limonchi, Fabian
Hopkinson, Christopher
da Rocha, Humberto R.
Gloor, Emanuel
Journal Title
Journal ISSN
Volume Title
Publisher
AGU Publications
Abstract
We constructed a whole carbon budget for a catchment in the Western Amazon Basin, combining
drainage water analyses with eddy covariance (EC) measured terrestrial CO2 fluxes. As fluvial C export can
represent permanent C export it must be included in assessments of whole site C balance, but it is rarely done. The
footprint area of the flux tower is drained by two small streams (~5–7 km2
) from which we measured the dissolved
inorganic carbon (DIC), dissolved organic carbon (DOC), particulate organic carbon (POC) export, and CO2 efflux.
The EC measurements showed the site C balance to be +0.7 9.7 Mg C ha 1 yr 1 (a source to the
atmosphere) and fluvial export was 0.3 0.04 Mg C ha 1 yr 1
. Of the total fluvial loss 34% was DIC, 37% DOC,
and 29% POC. The wet season was most important for fluvial C export. There was a large uncertainty
associated with the EC results and with previous biomass plot studies ( 0.5 4.1 Mg C ha 1 yr 1
); hence, it
cannot be concluded with certainty whether the site is C sink or source. The fluvial export corresponds to
only 3–7% of the uncertainty related to the site C balance; thus, other factors need to be considered to reduce
the uncertainty and refine the estimated C balance. However, stream C export is significant, especially for
almost neutral sites where fluvial loss may determine the direction of the site C balance. The fate of C
downstream then dictates the overall climate impact of fluvial export.
Description
Open access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) applies
Keywords
Eddy covariance , CO2 efflux , DIC , DOC , POC , Fluvial C export , Dissolved inorganic carbon , Dissolved organic carbon , Particulate organic carbon , Western Amazon Basin
Citation
Vihermaa, L. E., Waldron, S., Domingues, T., Grace, J., Cosio, E. G., Limonchi, F., Hopkinson, C., da Rocha, H. R., & Gloor, E. (2016). Fluvial carbon export from a lowland Amazonian rainforest in relation to atmospheric fluxes. Journal of Geophysical Research: Biogeosciences, 121(12), 3001-3018. https://doi.org/10.1002/2016JG003464