Photosynthetic performance associated with phosphorus availability in mats of Didymosphenia geminata (Bacillariophyceae) from Patagonia (Argentina and Chile)

Abstract: Recently reported blooms of Didymosphenia geminata from rivers in Argentinean and Chilean Patagonia, together with non-typical blooms reported from lake systems, have the potential to alter community and ecosystem dynamics of aquatic environments in the region. In an effort to quantify key aspects of ecosystem function of D. geminata mats in Patagonia, we describe for the first time photosynthesis–irradiance (P-E) curves of this species, associated P-E parameters (R, Pmax and α) and their relationship to other functional (alkaline phosphatase activity [APA] enzyme activity and chlorophyll a) and environmental variables (soluble reactive and organic phosphorous, electrical conductivity). Mats of D. geminata from lakes and rivers representing east and west sides of the Andes from 40°S to 46°S (i.e. much of current known distribution) varied mostly in the α and Pmax parameters of P-E curves. Southern systems showed a higher α and lower Pmax parameters than more northern sites on the east slope of t...