Figure 5: Physiological response of GX additions (TEP proxy) on N2 fixation.

Changes in N2 fixation (A), the proportion of the nifH expressing phototrophic and heterotrophic diazotrophs detected in the recovered cDNA (B), β-glucosidase activity rates (C) and bacterial carbon demand (D) following GX addition. Bottles were incubated for 48 h under dark + DCMU conditions. The asterisks above the columns represent significant differences (one-way ANOVA and a Fisher LSD means comparison test, P < 0.05) for mean values between additions.