Dinámica de captura de dióxido de carbono (CO2) en condiciones de radiación solar directa y difusa en los páramos de Zhurucay (Sur del Ecuador)

Abstract

The behavior of carbon (C) in the Andean páramo has not been thoroughly investigated and as a result, knowledge about the capture of carbon dioxide (CO2) based on the type of solar radiation in the ecosystem is almost nonexistent. This study identifies CO2 capture behavior based on the types of diffuse and direct radiation—and the photosynthetic activation conditions—by measuring these variables with an Eddy covariance technique (Eddy Covariance) and radiation sensors (BF3 pyranometer and LICOR LI-190R quantum sensor). We analyzed net ecosystem exchange (–NEE), photosynthetic photon flux density (PPFD), and diffuse and direct radiation over 17 identical days (12 sunny days and 5 cloudy days) throughout a period of 2 years (2017-2018). We obtained a response difference of 8% between the two types of radiation sensor. The photosynthetic activity (PPFD) showed normal activity on sunny days, contrary to the results on cloudy days. The average duration and capture of CO2 (–NEE) were quantitatively greater on sunny days than on cloudy days. The carbon fixation behavior was observed from 7:30 a.m. to 6:00 p.m. on sunny days and from 8:30 a.m. to 6:00 p.m. on cloudy days. Interestingly, it was shown that, with lower radiation values, values close to the –NEE measurements that were obtained at higher radiation values could also be obtained in less sunny months. Finally, this study highlights the limitations of CO2 capture in the Zhurucay páramo on cloudy days, similar to that of grasslands and deciduous and pine forests. This study contributes to a better understanding of carbon capture behavior by providing new insights that challenge existing studies and that will aid in the development of future investigations.