The main shift in response to CO2 was a growing increase in chlorophytes in elevated CO2 mesocosms (CO2 by time interaction P < 0.05), with an average across time and experiments of 9 % increase in the relative amount of chlorophytes from 55 % of total chlorophyll-a in ambient CO2 to 64 % in high CO2 in the absence of nutrient addition
(Fig. 4)