title: Variations in Amazon forest productivity correlated with foliar nutrients and modelled rates of photosynthetic carbon supply.
abstract: The rate of above-ground woody biomass production, W(P), in some western Amazon forests exceeds those in the east by a factor of 2 or more. Underlying causes may include climate, soil nutrient limitations and species composition. In this modelling paper, we explore the implications of allowing key nutrients such as N and P to constrain the photosynthesis of Amazon forests, and also we examine the relationship between modelled rates of photosynthesis and the observed gradients in W(P). We use a model with current understanding of the underpinning biochemical processes as affected by nutrient availability to assess: (i) the degree to which observed spatial variations in foliar [N] and [P] across Amazonia affect stand-level photosynthesis; and (ii) how these variations in forest photosynthetic carbon acquisition relate to the observed geographical patterns of stem growth across the Amazon Basin. We find nutrient availability to exert a strong effect on photosynthetic carbon gain across the Basin and to be a likely important contributor to the observed gradient in W(P). Phosphorus emerges as more important than nitrogen in accounting for the observed variations in productivity. Implications of these findings are discussed in the context of future tropical forests under a changing climate.
authors: Centre for Ecology and Hydrology, Wallingford, Oxon OX10 8BB, UK. L.Mercado@exeter.ac.uk
authors: Lina M
authors: LM
authors: Mercado
authors: Sandra
authors: S
authors: Patiño
authors: Tomas F
authors: TF
authors: Domingues
authors: Nikolaos M
authors: NM
authors: Fyllas
authors: Graham P
authors: GP
authors: Weedon
authors: Stephen
authors: S
authors: Sitch
authors: Carlos Alberto
authors: CA
authors: Quesada
authors: Oliver L
authors: OL
authors: Phillips
authors: Luiz E O C
authors: LE
authors: Aragão
authors: Yadvinder
authors: Y
authors: Malhi
authors: A J
authors: AJ
authors: Dolman
authors: Natalia
authors: N
authors: Restrepo-Coupe
authors: Scott R
authors: SR
authors: Saleska
authors: Timothy R
authors: TR
authors: Baker
authors: Samuel
authors: S
authors: Almeida
authors: Niro
authors: N
authors: Higuchi
authors: Jon
authors: J
authors: Lloyd
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D001938:Brazil; D002244:Carbon / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry; D003198:Computer Simulation; D008954:Models, Biological; D009584:Nitrogen / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry; D010788:Photosynthesis; D018515:Plant Leaves / Q000737:chemistry* / Q000254:growth & development; D018547:Plant Stems / Q000737:chemistry / Q000254:growth & development; D012987:Soil / Q000737:chemistry; D014197:Trees / Q000737:chemistry* / Q000254:growth & development; D014329:Tropical Climate; D014934:Wood / Q000737:chemistry / Q000254:growth & development
chemical_list: D012987:Soil; D002245:Carbon Dioxide; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen