Precipitation of hydrogen peroxide during winter storms and summer typhoons.

Hydrogen peroxide (HO) affects the activity of microbes, including archaea, and thereby influences the biogeochemical cycles of critical elements in marine and terrestrial environments. In this study, we measured the levels of HO associated with three classes of extreme wet precipitation events: winter storms, tropical storms, and typhoons. In conjunction with precipitation data, the measured HO concentration in a seawater reservoir receiving precipitation was used to estimate rainwater HO concentration and flux. The rainwater HO concentration during winter storms and coexisting storms (storms having combined maritime and continental origins) was a factor of 2-3 higher than the levels observed during the typhoons. Fluxes of HO in rainwater of 6 μM min or greater resulted in HO concentrations ~1 μM in the seawater reservoir. During all precipitation events, the HO concentration in the seawater reservoir was dominated by wet precipitation and reached levels greater than would be produced in situ by photochemical processes. During winter and coexisting storms, the rainwater HO concentrations were likely to have been enhanced by atmospheric photochemical reactions probably involving pollutants. An increase in the HO concentration in surface aqueous environments during extreme precipitation events will directly affect the microbial cycling of nitrogen and organic carbon.