Abstract ID: 109

(canceled) The effect of temperature on the Amazon forest: the results of both a warming and cooling experiment.

We perform both a warming and a cooling experiment to better understand the effects of temperature on the Amazon forest. For the cooling experiment, we look at how CO2 uptake is affected by cooling due to smoke using AERONET data and the km 83 eddy flux tower. Net ecosystem exchange increases significantly during smoky periods. Canopy temperatures cool by 0.5 degrees C at aerosol optical depths >0.7. Using a network of subcanopy PPFD sensors we found subcanopy diffuse light increases by ~ 1umol m-2 s-1. We use a model to then determine the relative effects of each on whole forest NEE. We determine that the increase in NEE during smoky periods is mainly due to the cooling of the canopy. For the warming experiment, we warmed leaves and branches on nine canopy level species for 6 months. Using leaf gas exchange and sap flow sensors we found evapotranspiration decreases following the warming for about 30 days. It then acclimates to the higher temperatures and returns to normal levels. Leaf level photosynthesis remains steady for 10 days but then declines by ~1 umol m-2 s-1 for the remainder of the experiment possibly due to irreversible temperature damage to the mesophyll.

Session:  Feedbacks to Climate - Emissions of natural and biomass burning particulates from vegetation and their effects on ecosystems and climate.

Presentation Type:  Oral