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

Wilcke, Wolfgang; Leimer, Sophia; Peters, Thorsten; Emck, Paul; Rollenbeck, Rütger; Trachte, Katja; Valarezo, Carlos; Bendix, Jörg (2013). The nitrogen cycle of tropical montane forest in Ecuador turns inorganic under environmental change. Global biogeochemical cycles, 27(4), pp. 1194-1204. American Geophysical Union 10.1002/2012GB004471

Preview

Text __ubnetapp02_user$_brinksma_Downloads_nitrogen cycle.pdf - Published Version Available under License Publisher holds Copyright. Download (1MB) | Preview

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.

Interest & Impact

Downloads

577 since deposited on 03 Jun 2014
15 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item