caa a22 4500 606219064 CHVBK 20210128101116.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s11104-015-2417-5 doi (NATIONALLICENCE)springer-10.1007/s11104-015-2417-5 Nitrogen isotopic patterns in tropical forests along a rainfall gradient in Northeast Brazil [Elektronische Daten] [Ana de Freitas, Everardo de Sá Barretto Sampaio, Andresa de Souza Ramos, Maria de Vasconcellos Barbosa, Rosângela Lyra, Elcida Araújo] Background and aims: The interpretation of ecosystem nitrogen isotopic patterns is subject to controversies since there are few surveys of signals along climate gradients within the same region. We determined the effects of a rainfall gradient, under high temperatures, on the soil and plant δ15N signals in Northeast Brazil. Methods: Nitrogen, carbon and δ15N signals were determined from coastal perennial to subhumid and semiarid deciduous forests to savanna - deciduous forest transition. Results: Soil C and N concentrations were linearly related and both related quadratically with mean annual rainfall while δ15N concentrations decreased with higher rainfall (16 to 4‰). Plant δ15N was 1-3‰ lower than soil δ15N (Δδ15N) in all areas. Only in the deciduous forests, leaves of target species had significantly lower 15 N signals than those of non-fixing species, allowing estimation of fixation. Conclusions: In the perennial forests the low signals indicated that the 15 N natural abundance method was not suitable to estimate fixation, while in the savanna - deciduous forest transition, high signals indicated that the legume species were not fixing. The smaller Δδ15N than those reported in cooler areas and the absence of rainfall effect indicates that, when high, temperature overrides the rainfall effect. Springer International Publishing Switzerland, 2015 N-15 depletion nationallicence Soil and plant δ15N nationallicence High temperature nationallicence Symbiotic nitrogen fixation nationallicence de Freitas Ana Universidade Federal Rural de Pernambuco, Av. Dom Manoel de Medeiros, s/n, CEP 52171-900, Dois Irmãos, Recife, PE, Brazil aut de Sá Barretto Sampaio Everardo Universidade Federal de Pernambuco, Av. Prof. Luís Freire, 1000, CEP 50740-540, Cidade Universitária, Recife, PE, Brazil aut de Souza Ramos Andresa Universidade Federal Rural de Pernambuco, Av. Dom Manoel de Medeiros, s/n, CEP 52171-900, Dois Irmãos, Recife, PE, Brazil aut de Vasconcellos Barbosa Maria Universidade Federal da Paraíba, João Pessoa, PB, Brazil aut Lyra Rosângela Institiuto do Meio Ambiente, Maceió, AL, Brazil aut Araújo Elcida Universidade Federal Rural de Pernambuco, Av. Dom Manoel de Medeiros, s/n, CEP 52171-900, Dois Irmãos, Recife, PE, Brazil aut Plant and Soil Springer International Publishing 391/1-2(2015-06-01), 109-122 0032-079X 391:1-2<109 2015 391 11104 https://doi.org/10.1007/s11104-015-2417-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11104-015-2417-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- de Freitas Ana Universidade Federal Rural de Pernambuco, Av. Dom Manoel de Medeiros, s/n, CEP 52171-900, Dois Irmãos, Recife, PE, Brazil aut NATIONALLICENCE 700 1- de Sá Barretto Sampaio Everardo Universidade Federal de Pernambuco, Av. Prof. Luís Freire, 1000, CEP 50740-540, Cidade Universitária, Recife, PE, Brazil aut NATIONALLICENCE 700 1- de Souza Ramos Andresa Universidade Federal Rural de Pernambuco, Av. Dom Manoel de Medeiros, s/n, CEP 52171-900, Dois Irmãos, Recife, PE, Brazil aut NATIONALLICENCE 700 1- de Vasconcellos Barbosa Maria Universidade Federal da Paraíba, João Pessoa, PB, Brazil aut NATIONALLICENCE 700 1- Lyra Rosângela Institiuto do Meio Ambiente, Maceió, AL, Brazil aut NATIONALLICENCE 700 1- Araújo Elcida Universidade Federal Rural de Pernambuco, Av. Dom Manoel de Medeiros, s/n, CEP 52171-900, Dois Irmãos, Recife, PE, Brazil aut NATIONALLICENCE 773 0- Plant and Soil Springer International Publishing 391/1-2(2015-06-01), 109-122 0032-079X 391:1-2<109 2015 391 11104