02746naa a2200397 a 450000100080000000500110000800800410001902400270006010000230008724501810011026000090029152015010030065000130180165000200181465000210183465000100185565000220186565300450188765300350193265300090196765300350197665300380201170000260204970000140207570000170208970000180210670000210212470000300214570000170217570000170219270000160220970000210222570000170224670000190226377300660228221570882023-11-13       2023    bl uuuu     u00u1 u    #d7 a10.1111/gcb.169332DOI1 aRESTREPO-COUPE, N.  aAsymmetric response of Amazon forest water and energy fluxes to wet and dry hydrological extremes reveals onset of a local drought-induced tipping point.h[electronic resource]  c2023  aUnderstanding the effects of intensification of Amazon basin hydrological cycling manifest as increasingly frequent floods and droughts'on water and energy cycles of tropical forests is essential to meeting the challenge of predicting ecosystem responses to climate change, including forest 'tipping points'. Here, we investigated the impacts of hydrological extremes on forest function using 12+ years of observations (between 2001-2020) of water and energy fluxes from eddy covariance, along with associated ecological dynamics from biometry, at the Tapajós National Forest. Measurements encompass the strong 2015-2016 El Niño drought and La Niña 2008-2009 wet events. We found that the forest responded strongly to El Niño-Southern Oscillation (ENSO): Drought reduced water availability for evapotranspiration (ET) leading to large increases in sensible heat fluxes (H). Partitioning ET by an approach that assumes transpiration (T) is proportional to photosynthesis, we found that water stress-induced reductions in canopy conductance (Gs) drove T declines partly compensated by higher evaporation (E). By contrast, the abnormally wet La Niña period gave higher T and lower E, with little change in seasonal ET. Both El Niño-Southern Oscillation (ENSO) events resulted in changes in forest structure, manifested as lower wet-season leaf area index. However, only during El Niño 2015-2016, we observed a breakdown in the strong meteorological control of transpiration fluxes (via energy  aAmazonia  aEddy covariance  aTropical forests  aÁgua  aFloresta Tropical  aÁgua e sazonalidade do fluxo de energia  aEcosystem-climate interactions  aENSO  aInterações ecossistema-clima  aWater and energy flux seasonality1 aCHRISTOFFERSEN, B. O.1 aLONGO, M.1 aALVES, L. F.1 aCAMPOS, K. S.1 aARAUJO, A. C. de1 aOLIVEIRA JUNIOR, R. C. de1 aPROHASKA, N.1 aSILVA, R. da1 aTAPAJOS, R.1 aWIEDEMANN, K. T.1 aWOFSY, S. C.1 aSALESKA, S. R.  tGlobal Change Biologygv. 29, n. 21, p. 6077-6092, Nov. 2023.