Department of Earth System Science

Hydrogen peroxide concentrations have been determined in marine rain from the Gulf of Mexico, the western Atlantic Ocean, and one rain event off the Florida Keys. In several cases, simultaneous measurements of the concentration of H₂O₂ in the surface ocean were also determined. These measurements were made with the ship under way using a continuous flow sampling system with the intake at the bow. In shallow stratified layers, rain events can increase the existing hydrogen peroxide concentration by a factor greater than 10 and dramatically increase the mean H₂O₂ concentration of mixed depth layers of 50 m or more. Rain is a significant transient source of H₂O₂ in the surface ocean.