Skip to main content

Research Repository

Advanced Search

Climatic and geomorphic controls on the erosion of terrestrial biomass from subtropical mountain forest

Hilton, R.G.; Galy, A.; Hovius, N.; Kao, S.J.; Horng, M.J.; Chen, H.

Climatic and geomorphic controls on the erosion of terrestrial biomass from subtropical mountain forest Thumbnail


Authors

R.G. Hilton

A. Galy

N. Hovius

S.J. Kao

M.J. Horng

H. Chen



Abstract

[1] Erosion of particulate organic carbon (POC) occurs at very high rates in mountain river catchments, yet the proportion derived recently from atmospheric CO2 in the terrestrial biosphere (POCnon-fossil) remains poorly constrained. Here we examine the transport of POCnon-fossil in mountain rivers of Taiwan and its climatic and geomorphic controls. In 11 catchments we have combined previous geochemical quantification of POC source (accounting for fossil POC from bedrock), with measurements of water discharge (Qw) and suspended sediment concentration over 2 years. In these catchments, POCnon-fossil concentration (mg L−1) was positively correlated with Qw, with enhanced loads at high flow attributed to rainfall driven supply of POCnon-fossil from forested hillslopes. This climatic control on POCnon-fossil transport was moderated by catchment geomorphology: the gradient of a linear relation of POCnon-fossil concentration and Qw increased as the proportion of steep hillslopes (>35°) in the catchment increased. The data suggest enhanced supply of POCnon-fossil by erosion processes which act most efficiently on the steepest sections of forest. Across Taiwan, POCnon-fossil yield was correlated with suspended sediment yield, with a mean of 21 ± 10 tC km−2 yr−1. At this rate, export of POCnon-fossil imparts an upper bound on the time available for biospheric growth, of ∼800 yr. Over longer time periods, POCnon-fossil transferred with large amounts of clastic sediment can contribute to sequestration of atmospheric CO2 if buried in marine sediments. Our results show that this carbon transfer should be enhanced in a wetter and stormier climate, and the rates moderated on geological timescales by the regional tectonic setting.

Citation

Hilton, R., Galy, A., Hovius, N., Kao, S., Horng, M., & Chen, H. (2012). Climatic and geomorphic controls on the erosion of terrestrial biomass from subtropical mountain forest. Global Biogeochemical Cycles, 26(3), Article GB3014. https://doi.org/10.1029/2012gb004314

Journal Article Type Article
Publication Date Sep 1, 2012
Deposit Date Jul 30, 2012
Publicly Available Date Mar 28, 2024
Journal Global Biogeochemical Cycles
Print ISSN 0886-6236
Publisher American Geophysical Union
Peer Reviewed Peer Reviewed
Volume 26
Issue 3
Article Number GB3014
DOI https://doi.org/10.1029/2012gb004314

Files

Published Journal Article (733 Kb)
PDF

Copyright Statement
Hilton, R.G. and Galy, A. and Hovius, N. and Kao, S.J. and Horng, M.J. and Chen, H. (2012), 'Climatic and geomorphic controls on the erosion of terrestrial biomass from subtropical mountain forest, Global biogeochemical cycles, 26 (3). GB3014, 10.1029/2012GB004314. To view the published open abstract, go to http://dx.doi.org/10.1029/2012GB004314





You might also like



Downloadable Citations