Mean values of the main physical, chemical and biological variables measured under initial conditions of the experiment.

Abbreviations: Temperature (average water column); TP = total phosphorus; TDP = total dissolved phosphorus; TN = total nitrogen; TDN = total dissolved nitrogen; DOC = dissolved organic carbon; BP = bacterial production; R = planktonic respiration; BR = bacterial respiration; BA = bacterial abundance; Chl a = chlorophyll a; AB = algae biomass; CB = ciliate biomass.