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

Research output: Contribution to journalJournal article

Published

  • Ryan Pereira
  • C. Isabella Bovolo
  • Robert G. M. Spencer
  • Peter J. Hernes
  • Edward Tipping
  • Andrea Vieth-Hillebrand
  • Nikolai Pedentchouk
  • Nick A. Chappell
  • Geoff Parkin
  • Thomas Wagner
Journal publication date28/02/2014
JournalGeophysical Research Letters
Journal number4
Volume41
Number of pages7
Pages1202–1208
Original languageEnglish

Abstract

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 h 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 mins (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 unquantified source of riverine CO2 outgassing in tropical headwaters, requiring further consideration.

Bibliographic note

©2014. American Geophysical Union. All Rights Reserved. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.