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Wilcke, W.; Velescu, A.; Leimer, S.; Blotevogel, S.; Alvarez Figueroa, P.A. &amp; Valarezo, C. (2020): <b>Total organic carbon concentrations in ecosystem solutions of a remote tropical montane forest respond to global environmental change</b>. <i>Global Change Biology</i> <b>26</b>, 6989–7005.

Resource Description

Title: Total organic carbon concentrations in ecosystem solutions of a remote tropical montane forest respond to global environmental change
FOR816dw ID: 1879
Publication Date: 2020-09-16
License and Usage Rights:
Resource Owner(s):
Individual: Wolfgang Wilcke
Contact:
Individual: Andre Velescu
Contact:
Individual: Sophia Leimer
Contact:
Individual: Simon Blotevogel
Contact:
Individual: Pablo Armando Alvarez Figueroa
Contact:
Individual: Carlos Valarezo
Contact:
Abstract:
The response of organic carbon (C) concentrations in ecosystem solutions to environmental change affects the release of dissolved organic matter (DOM) from forests to surface and groundwaters. We determined the total organic C (TOC) concentrations (filtered <1–7 μm) and the ratios of TOC/dissolved organic nitrogen (DON) concentrations, electrical conductivity (EC), and pH in all major ecosystem solutions of a tropical montane forest from 1998 to 2013. The forest was located on the rim of the Amazon basin in Ecuador and experienced increasing numbers of days with >25°C, decreasing soil moisture, and rising nitrogen (N) deposition from the atmosphere during the study period. In rainfall, throughfall, mineral soil solutions (at the 0.15- and 0.30-m depths), and streamflow, TOC concentrations and fluxes decreased significantly from 1998 to 2013, while they increased in stemflow. TOC/DON<br/> ratios decreased significantly in rainfall, throughfall, soil solution at the 0.15-m depth, and streamflow. Based on Δ14C values, the TOC in rainfall and mineral soil solutions was 1 year old and that of litter leachate was 10 years old. The pH in litter leachate decreased with time, that in mineral soil solutions increased, while those in the other ecosystem solutions did not change. Thus, reduced TOC solubility because of lower pH values cannot explain the negative trends in TOC concentrations in most ecosystem<br/> solutions. The increasing TOC concentrations and EC in stemflow pointed at an increased leaching of TOC and other ions from the bark. Our results suggest an accelerated degradation of DOM, particularly of young DOM, associated with the production of N-rich compounds simultaneously to changing climatic conditions and increasing N availability. Thus, environmental change increased the CO2 release to the atmosphere but reduced DOM export to surface and groundwater.
Keywords:
| Dissolved organic carbon | time series | carbon-14 dating | TOC:DON ratio | ecosystem fluxes |
Literature type specific fields:
ARTICLE
Journal: Global Change Biology
Volume: 26
Page Range: 6989–7005
Publisher: Wiley & Sons Ltd.
Metadata Provider:
Individual: Wolfgang Wilcke
Contact:
Online Distribution:
Download File: http://www.lcrs.de/publications.do?citid=1879


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