The nitrogen cycle of tropical montane forest in Ecuador turns inorganic under environmental change

Wilcke W, Leimer S, Peters T, Emck P, Rollenbeck R, Trachte K, Valarezo C, Bendix J (2013)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2013

Journal

Global Biogeochemical Cycles American Geophysical Union (AGU)

Publisher: American Geophysical Union (AGU)

DOI: 10.1002/2012GB004471

Abstract

Water-bound nitrogen (N) cycling in temperate terrestrial ecosystems of the Northern Hemisphere is today mainly inorganic because of anthropogenic release of reactive N to the environment. In little-industrialized and remote areas, in contrast, a larger part of N cycling occurs as dissolved organic N (DON). In a north Andean tropical montane forest in Ecuador, the N cycle changed markedly during 1998–2010 along with increasing N deposition and reduced soil moisture. The DON concentrations and the fractional contribution of DON to total N significantly decreased in rainfall, throughfall, and soil solutions. This inorganic turn of the N cycle was most pronounced in rainfall and became weaker along the flow path of water through the system until it disappeared in stream water. Decreasing organic contributions to N cycling were caused not only by increasing inorganic N input but also by reduced DON production and/or enhanced DON decomposition. Accelerated DON decomposition might be attributable to less waterlogging and higher nutrient availability. Significantly increasing NO3-N concentrations and NO3-N/NH4-N concentration ratios in throughfall and litter leachate below the thick organic layers indicated increasing nitrification. In mineral soil solutions, in contrast, NH4-N concentrations increased and NO3-N/NH4-N concentration ratios decreased significantly, suggesting increasing net ammonification. Our results demonstrate that the remote tropical montane forests on the rim of the Amazon basin experienced a pronounced change of the N cycle in only one decade. This change likely parallels a similar change which followed industrialization in the temperate zone of the Northern Hemisphere more than a century ago.

Authors with CRIS profile

Thorsten Peters Institut für Geographie

Involved external institutions

Karlsruhe Institute of Technology (KIT) DE Germany (DE) Philipps-Universität Marburg DE Germany (DE)

How to cite

APA:

Wilcke, W., Leimer, S., Peters, T., Emck, P., Rollenbeck, R., Trachte, K.,... Bendix, J. (2013). The nitrogen cycle of tropical montane forest in Ecuador turns inorganic under environmental change. Global Biogeochemical Cycles. https://dx.doi.org/10.1002/2012GB004471

MLA:

Wilcke, Wolfgang, et al. "The nitrogen cycle of tropical montane forest in Ecuador turns inorganic under environmental change." Global Biogeochemical Cycles (2013).

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