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Gewählte Publikation:

Wania, R., Hietz, P., Wanek, W..
(2002): Natural 15N abundance of epiphytes depends on the position within the forest canopy: source signals and isotope fractionation.
Plant Cell and Environment, 25, 4, 581-589

The natural N-15 abundance (delta(15)N) of epiphytes and its N sources were studied in the canopy of a lowland rainforest in Costa Rica. Vascular and non-vascular epiphytes and canopy soils were collected from four canopy zones and analysed for N contents and delta(15)N signals. In addition, the N concentrations and delta(15)N signatures of bulk precipitation, throughfall and stemflow were measured during the wet and the dry season. The delta(15)N values of epiphyte leaves decreased significantly from the lower zones (means of -3.9 and -4.3parts per thousand) to the upper zones (means of -5.4 and -6.1parts per thousand) of the canopy. In contrast, delta(15)N signatures of canopy soils (average -0.3parts per thousand) differed little between the zones. Bulk deposition was enriched in N-15 (+4.3parts per thousand) compared to all other potential N sources and was higher than throughfall and stemflow (+0.5 to -1.3parts per thousand). delta(15)N values of atmospheric deposition were inversely related to those of the epiphyte leaves, whereas N isotopic composition of canopy soils did not vary significantly. Consequently, it is concluded that the variations in foliar N isotope composition of epiphytes were not simply caused by utilization of isotopically different N sources, but by different N-15 discrimination during N acquisition.
Autor*innen der BOKU Wien:
Hietz Peter
BOKU Gendermonitor:

Find related publications in this database (Keywords)
delta N-15
delta C-13
bulk precipitation
tropical lowland rainforest

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