Decadal carbon discharge by a mountain stream is dominated by coarse organic matter

Turowski, J.M.; Hilton, R.G.; Sparkes, R.

doi:10.1130/g37192.1

Decadal carbon discharge by a mountain stream is dominated by coarse organic matter

Turowski, J.M.; Hilton, R.G.; Sparkes, R.

Authors

J.M. Turowski

R.G. Hilton

R. Sparkes

Abstract

Rapid erosion in mountain forests results in high rates of biospheric particulate organic carbon (POC) export by rivers, which can contribute to atmospheric carbon dioxide drawdown. However, coarse POC (CPOC) carried by particles >∼1 mm is rarely quantified. In a forested pre-Alpine catchment, we measured CPOC transport rates and found that they increase more rapidly with water discharge than fine POC (<1 mm) and dissolved organic carbon (DOC). As a result, decadal estimates of CPOC yield of 12.3 ± 1.9 t C km–2 yr–1 are higher than for fine POC and DOC, even when excluding 4 extreme flood events. When including these floods, CPOC dominates organic carbon discharge (∼80%). Most CPOC (69%) was water logged and denser than water, suggesting that CPOC has the potential to contribute to long-term sedimentary burial. Global fluxes remain poorly constrained, but if the transport behavior of CPOC shown here is common to other mountain streams and rivers, then neglecting CPOC discharge could lead to a large underestimation of the global transfer of biospheric POC from land to ocean.

Citation

Turowski, J., Hilton, R., & Sparkes, R. (2016). Decadal carbon discharge by a mountain stream is dominated by coarse organic matter. Geology, 44(1), 27-30. https://doi.org/10.1130/g37192.1

Journal Article Type	Article
Acceptance Date	Oct 29, 2015
Online Publication Date	Nov 20, 2015
Publication Date	Jan 1, 2016
Deposit Date	Nov 23, 2015
Publicly Available Date	Nov 20, 2016
Journal	Geology
Print ISSN	0091-7613
Electronic ISSN	1943-2682
Publisher	Geological Society of America
Peer Reviewed	Peer Reviewed
Volume	44
Issue	1
Pages	27-30
DOI	https://doi.org/10.1130/g37192.1