Stable N isotope composition of nitrate reflects N transformations during the passage of water through a montane rain forest in Ecuador
Data(s) |
2011
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Resumo |
Knowledge of the fate of deposited N in the possibly N-limited, highly biodiverse north Andean forests is important because of the possible effects of N inputs on plant performance and species composition. We analyzed concentrations and fluxes of NO3 −–N, NH4 +–N and dissolved organic N (DON) in rainfall, throughfall, litter leachate, mineral soil solutions (0.15–0.30 m depths) and stream water in a montane forest in Ecuador during four consecutive quarters and used the natural 15N abundance in NO3 − during the passage of rain water through the ecosystem and bulk δ15N values in soil to detect N transformations. Depletion of 15N in NO3 − and increased NO3 −–N fluxes during the passage through the canopy and the organic layer indicated nitrification in these compartments. During leaching from the organic layer to mineral soil and stream, NO3 − concentrations progressively decreased and were enriched in 15N but did not reach the δ15N values of solid phase organic matter (δ15N = 5.6–6.7‰). This suggested a combination of nitrification and denitrification in mineral soil. In the wettest quarter, the δ15N value of NO3 − in litter leachate was smaller (δ15N = −1.58‰) than in the other quarters (δ15N = −9.38 ± SE 0.46‰) probably because of reduced mineralization and associated fractionation against 15N. Nitrogen isotope fractionation of NO3 − between litter leachate and stream water was smaller in the wettest period than in the other periods probably because of a higher rate of denitrification and continuous dilution by isotopically lighter NO3 −–N from throughfall and nitrification in the organic layer during the wettest period. The stable N isotope composition of NO3 − gave valuable indications of N transformations during the passage of water through the forest ecosystem from rainfall to the stream. |
Formato |
application/pdf application/pdf |
Identificador |
http://boris.unibe.ch/9175/1/Schwarzetal2011Biogeochemistry.pdf http://boris.unibe.ch/9175/2/art%253A10.1007%252Fs10533-010-9434-5.pdf Schwarz, Martin T.; Oelmann, Yvonne; Wilcke, Wolfgang (2011). Stable N isotope composition of nitrate reflects N transformations during the passage of water through a montane rain forest in Ecuador. Biochemistry, 102(1-3), pp. 195-208. Washington, D.C.: American Chemical Society 10.1007/s10533-010-9434-5 <http://dx.doi.org/10.1007/s10533-010-9434-5> doi:10.7892/boris.9175 info:doi:10.1007/s10533-010-9434-5 urn:issn:0006-2960 |
Idioma(s) |
eng |
Publicador |
American Chemical Society |
Relação |
http://boris.unibe.ch/9175/ |
Direitos |
info:eu-repo/semantics/openAccess info:eu-repo/semantics/restrictedAccess |
Fonte |
Schwarz, Martin T.; Oelmann, Yvonne; Wilcke, Wolfgang (2011). Stable N isotope composition of nitrate reflects N transformations during the passage of water through a montane rain forest in Ecuador. Biochemistry, 102(1-3), pp. 195-208. Washington, D.C.: American Chemical Society 10.1007/s10533-010-9434-5 <http://dx.doi.org/10.1007/s10533-010-9434-5> |
Palavras-Chave | #910 Geography & travel |
Tipo |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion PeerReviewed |