Asymbiotic nitrogen fixation in the phyllosphere of the Amazon forest: Changing nitrogen cycle paradigms

Autor(es)

Fornazier Moreira, Julio Cezar ^[1] ; Brum, Mauro ^[2] ; de Almeida, Lidiane Cordeiro ^[3] ; Barrera-Berdugo, Silvia ^{[1, 4]} ; de Souza, Andre Alves ^[1] ; de Camargo, Plinio Barbosa ^[5] ; Oliveira, Rafael Silva ^[2] ; Alves, Luciana Ferreira ^{[6, 2]} ; Pimentel Rosado, Bruno Henrique ^[3] ; Lambais, Marcio Rodrigues ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Soil Sci Dept, Av Padua Dias 11, BR-13418900 Piracicaba, SP - Brazil

^[2] State Univ Campinas UNICAMP, Inst Biol, Programa Pos Grad Ecol, Dept Plant Biol, POB 6109, BR-13083970 Campinas, SP - Brazil

^[3] Rio De Janeiro State Univ UERJ, IBRAG, Dept Ecol, R Sao Francisco Xavier, 524, PHLC, Sala 220, Rio De Janeiro, RJ - Brazil

^[4] Univ Nacl Abierta & Distancia, CIAB, Dg 25 Carrera 23 Diagonal 25F, Dosquebradas - Colombia

^[5] Univ Sao Paulo, Ctr Nucl Energy Agr, 303 Centenario Ave, BR-13400970 Piracicaba, SP - Brazil

^[6] Univ Calif Los Angeles, Ctr Trop Res, Inst Environm & Sustainabil, Los Angeles, CA 90095 - USA

• Tipo de documento: Artigo Científico
• Fonte: Science of The Total Environment; v. 773, JUN 15 2021.
• Citações Web of Science: 0

Resumo

Biological nitrogen fixation is a key process for the maintenance of natural ecosystems productivity. In tropical forests, the contribution of asymbiotic nitrogen fixation (ANF) to the nitrogen (N) input has been underestimated, even though few studies have shown that ANF may be as important as symbiotic nitrogen fixation in such environments. The inputs and abiotic modulators of ANF in the Amazon forest are not completely understood. Here, we determined ANF rates and estimated the N inputs from ANF in the phyllosphere, litter and rhizospheric soil of nine tree species in the Amazon forest over time, including an extreme drought period induced by the El Nino-Southern Oscillation. Our data showed that ANF rates in the phyllosphere were 2.8- and 17.6-fold higher than in the litter and rhizospheric soil, respectively, and was highly dependent on tree taxon. Sampling time was the major factor modulating ANF in all forest compartments. At the driest period, ANF rates were approximately 1.8-fold and 13.1-fold higher than at periods with higher rainfall, before and after the extreme drought period, respectively. Tree species was a key modulator of ANF in the phyllosphere, as well as N and Vanadium concentrations. Carbon, molybdenum and vanadium concentrations were significant modulators of ANF in the litter. Based on ANF rates at the three sampling times, we estimated that the N input in the Amazon forest through ANF in the phyllosphere, litter and rhizospheric soil, was between 0.459 and 0.714 kg N ha(-1) yr(-1). Our results highlight the importance of ANF in the phyllosphere for the N input in the Amazon forest, and suggest that changes in the patterns of ANF driven by large scale climatic events may impact total N inputs and likely alter forest productivity. (C) 2021 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 16/15932-4 - Análise comparativa de comunidades bacterianas na filosfera, serapilheira e rizosfera de espécies arbóreas da floresta Amazônica
• Beneficiário: Julio Cezar Fornazier Moreira
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 16/04095-4 - Fitobiomas da floresta Amazônica: diversidade e funcionalidade das comunidades bacterianas da filosfera, rizosfera e serapilheira.
• Beneficiário: Marcio Rodrigues Lambais
• Modalidade de apoio: Auxílio à Pesquisa - Regular