Alvarez Figueroa, P.A.; Velescu, A.; Pierick, K.; Homeier, J. & Wilcke, W. (2023): <b>Carbon stable isotope ratios of dissolved organic matter as a tool to identify its sources and transformations in a tropical montane forest in Ecuador</b>. <i>Environmental Science and Technology</i> <b>57</b>, 14983−14993.
Resource Description
Title:
Carbon stable isotope ratios of dissolved organic matter as a tool to identify its sources and transformations in a tropical montane forest in Ecuador
FOR816dw ID:
1991
Publication Date:
2023-10-12
License and Usage Rights:
Resource Owner(s):
Individual:
Pablo Armando Alvarez Figueroa
Contact:
email:
pablo.alvarez <at> kit.edu
Institute of Geography and Geoecology
Reinhard-Paumeister-Platz 1
76131 Karlsruhe
Germany
Individual:
Andre Velescu
Contact:
email:
andre.velescu <at> kit.edu
Karlsruher Institut für Technologie
Institut für Geographie und Geoökologie
Arbeitsgruppe Geomorphologie und Bodenkunde
Reinhard-Baumeister-Platz 1
76131 Karlsruhe
Germany
email:
jhomeie <at> gwdg.de
Faculty of Resource Management
University of Applied Sciences and Arts (HAWK)
37077 Göttingen
Germany
Individual:
Wolfgang Wilcke
Contact:
email:
wolfgang.wilcke <at> kit.edu
Karlsruhe Institute of Technology
Institute of Geography and Geoecology
Reinhard-Baumeister-Platz 1
76131 Karlsruhe
Baden-Württemberg
Germany
Abstract:
Dissolved organic matter (DOM) contributes to forest C cycling. We assessed temporal variability, sources, and transformations of DOM during four years in a tropical montane forest with the help of stable C isotope ratios (δ13C values). We measured δ13C values of DOM in rainfall (RF), throughfall (TF), stemflow (SF), litter leachate (LL), soil solutions at the 0.15 and 0.30 m depths (SS15, SS30), and streamflow (ST)with TOC-IRMS. The δ13C values of DOM did not vary seasonally. We detected an event with a high δ13C value likely attributable to black carbon from local pasture fires. The mean δ13C values of DOM outside the event decreased in the order, RF (−26.0 ± 1.3‰) > TF (−28.7 ± 0.3‰) > SF (−29.2 ± 0.2‰) > LL (−29.6 ± 0.2‰) because of increasing leaching of C-isotopically light compounds. The higher δ13C values of DOM in SS15 (−27.8 ± 1.0‰), SS30 (−27.6 ± 1.1‰), and ST (−27.9 ± 1.1‰) than in the above-ground solutions suggested that roots and root exudates are major belowground DOM sources. Although in DOM the C/N ratios correlated with the δ13C values when all solutions were considered, this was not the case for SS15, SS30, and ST alone. Thus, the δ13C values of DOM provide an additional tool to assess the sources and turnover of DOM.
email:
andre.velescu <at> kit.edu
Karlsruher Institut für Technologie
Institut für Geographie und Geoökologie
Arbeitsgruppe Geomorphologie und Bodenkunde
Reinhard-Baumeister-Platz 1
76131 Karlsruhe
Germany
