Lauren Albert Aline Lopes Natalia Restrepo-Coupe Matthew Hayek Kenia T. Wiedemann Kaiyu Guan Scott C. Stark Bradley Christoffersen Neill Prohaska Julia V. Tavares Suelen Marostica Hideki Kobayashi Maurocio L. Ferreira Kleber Silva Campos Rodrigo da Silva Paulo M. Brando Dennis G. Dye Travis E. Huxman Alfredo Huete Bruce Nelson Scott Saleska Jin Wu 2016 <p>In evergreen tropical forests, the extent, magnitude, and controls on photosynthetic seasonality are poorly resolved and inadequately represented in Earth system models. Combining camera observations with ecosystem carbon dioxide fluxes at forests across rainfall gradients in Amaz&ocirc;nia, we show that aggregate canopy phenology, not seasonality of climate drivers, is the primary cause of photosynthetic seasonality in these forests. Specifically, synchronization of new leaf growth with dry season litterfall shifts canopy composition toward younger, more light-use efficient leaves, explaining large seasonal increases (~27%) in ecosystem photosynthesis. Coordinated leaf development and demography thus reconcile seemingly disparate observations at different scales and indicate that accounting for leaf-level phenology is critical for accurately simulating ecosystem-scale responses to climate change.</p> application/pdf 10.1126/science.aad5068 en American Association for the Advancement of Science Leaf development and demography explain photosynthetic seasonality in Amazon evergreen forests article