Average (±SD) response in the microbial extracellular enzymatic activities (EEAs), to different H2O2 concentrations in the experiments done with epi- meso- and bathypelagic waters at Stn. 6–16 (n = 9).

Also shown is the corresponding percentage of EEA inhibited (Inh) compared to the control without amendment of H2O2. LAPase: leucine aminopeptidase, APase: alkaline phosphatase, BGase: β-glucosidase. OML: oxygen minimum layer, NADW: North Atlantic Deep Water.