Complex sentence: Josep Peñuelas i Reixach (born 1958) is a Research Professor at the National Research Council of Spain (CSIC) who studies plant ecophysiology and atmosphere-biosphere interactions.
Split into simpler sentences: Josep Peñuelas i Reixach (born 1958) is a Research Professor of the National Research Council of Spain (CSIC). He is an ecologist working on plant ecophysiology and atmosphere-biosphere interactions.