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A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function
Published on: November 21, 2015
Cloud cover limits net CO2 uptake and growth of a rainforest tree during tropical rainy seasons
Eric A Graham1, Stephen S Mulkey, Kaoru Kitajima
1Department of Botany, 220 Bartram Hall, University of Florida, Gainesville, FL 34002-8526, USA.
Abstract:
Recent global-scale analyses indicate that climate variability affects net carbon storage but regard temperature and precipitation to be the main contributors. Seasonal and interannual variation in light availability may also limit CO(2) uptake. As an experimental test of light limitation by cloud cover during tropical rainy seasons and by the unusually heavy cloud cover associated with La Niña, we installed high-intensity lamps above the forest canopy to augment light for Luehea seemannii, a tropical canopy tree species, during cloudy periods of 1999-2000. Light augmentation only partially compensated for the reduction in photosynthetic photon flux density caused by clouds. Nonetheless, leaves acclimated to the augmented irradiance, and photosynthesis, vegetative growth, and reproduction increased significantly. Light, rather than water, temperature, or leaf nitrogen, was the primary factor limiting CO(2) uptake during the rainy season.
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