Fig. 7. Total microbial activity and non-additive interactive effects as a function of organic matter chemodiversity.

Non-additive interactive effects start above the red line, which visualises the sum of microbial activity (i.e., CO₂ production) when carbon sources are isolated. In the zone of non-additive interactive effects, the increase of microbial activity is not linear and reaches a steady state when chemodiversity is high. Furthermore, we suggest a community effect that influences the slope and the maxima of the curve: while DL1:1 and b-DL1:1 had the same conditions in regard to organic matter chemodiversity, DL1:1 had the highest microbial activity resulting from a high community complexity, compared to b-DL1:1- simplified bacterial community composition. Daphnia: daphnia only; D:L: daphnia and leaves in a given ratio with a complex microbial community; Leaves: leaves only; b-DL1:1: daphnia and leaves (ratio 1:1) with the bacterial community only.