We analyzed the eddy covariance measurements of momentum, mass, and energy taken daily throughout five consecutive seasonal courses (i.e. 840 d after planting) of a pineapple [Ananas comosus (L.) Merr. cv. Red Spanish] field growing in the Orinoco lowlands. This field provides an opportunity for micrometeorological studies because of the flat and windy site; the seasonal weather including ENSO effects and the Crassulacean Acid Metabolism (CAM) physiology of the crop were additional attributes. Soil CO2 flux was quantified and added to the net ecosystem exchange in order to obtain the canopy flux (FC). The canopy CO2 flux partially followed the four phases of CAM sensu Osmond (1978). The daily pattern of gaseous exchange in pineapple showed a continuum spectrum in which a major proportion of CO2 uptake occurring during the daytime was common and in which the CAM expression was related to day and nocturnal CO2 uptake. However, the benefits of CO2 uptake at low water cost were constrained by the limited nocturnal CO2 uptake. Seasonal and ontogenetic changes affected the energy exchange as well as the partitioning of available energy into sensible (QH) and latent (QLE) heat. When the hourly net radiation (QRn) reached its maximum value, latent heat flux (QLE) to available energy throughout the vegetative and reproductive stages was 0.65, 0.05, 0.30, 0.11, and 0.33 for the 1997 wet season, 1997/98 dry season, 1998 wet season, 1998/99 dry season, and 1999 wet season, respectively. Throughout the growth period, we found the pivotal role of surface conductance (gs) in both QLE and FC. Furthermore, the canopy responded to environmental changes. During the wet seasons the gs was strongly influenced by humidity mole fraction deficit and was usually lower than aerodynamic conductance, whereas during the dry seasons, soil water deficit limited evapotranspiration and production rates. For the fully canopy cover, the hourly trend of marginal water cost of pineapple carbon gain in the dry seasons indicated that gs became sufficiently efficient to reduce the amount of water transported per unit of carbon gain. In the wet season, the coupling of CO2 uptake and stomatal conductance was more effective in maintaining a higher proportionality between QLE and gs. and J. San-José, R. Montes, N. Nikonova.