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Mobilization of optically invisible dissolved organic matter in response to rainstorm events in a tropical forest headwater river

Lookup NU author(s): Dr Ryan Pereira, Dr Isabella Bovolo, Dr Rob Spencer, Dr Geoffrey ParkinORCiD, Professor Thomas Wagner



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


This study emphasizes the importance of rainstorm events in mobilizing carbon at the soil-stream interface from tropical rainforests. Half-hourly geochemical/isotopic records over a 13.5 hour period from a 20 km2 tropical rainforest headwater in Guyana show an order of magnitude increase in dissolved organic carbon (DOC) concentration in less than 30 minutes (10.6-114 mg/L). The composition of DOC varies significantly and includes optically invisible dissolved organic matter (iDOM) that accounts for a large proportion (4-89%) of the total DOC, quantified using size exclusion chromatography (SEC). SEC suggests that iDOM is comprised of low molecular weight organic moieties, which are likely sourced from fresh leaf litter and/or topsoil, as shown in soils from the surrounding environment. Although poorly constrained at present, the presence of iDOM further downstream during the wet season suggests that this organic matter fraction may represent an un-quantified source of riverine CO2 outgassing in tropical headwaters, requiring further consideration.

Publication metadata

Author(s): Pereira R, Bovolo CI, Spencer RGM, Hernes PJ, Tipping E, Vieth-Hillebrand A, Pedentchouk N, Chappell NA, Parkin G, Wagner T

Publication type: Article

Publication status: Published

Journal: Geophysical Research Letters

Year: 2014

Volume: 41

Issue: 4

Pages: 1202-1208

Print publication date: 19/02/2014

Online publication date: 19/02/2014

Acceptance date: 15/01/2014

Date deposited: 25/03/2014

ISSN (print): 0094-8276

ISSN (electronic): 1944-8007

Publisher: Wiley-Blackwell


DOI: 10.1002/2013GL058658


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Funder referenceFunder name
Newcastle Institute for Research on Sustainability
Royal Society Wolfson Research Merit Award
ATN/MC-11548-GYInter-American Development Bank