PEROXIDE VARIATIONS IN THE SARGASSO SEA

This paper presents a time series study of H2O2 distributions and vari ability at an oligotrophic station in the North Atlantic. Hydrogen per oxide was examined over eleven consecutive days at 1 and 3 m. The aver age concentration exceeded 100 nM with daily variations of about 40 nM at both depths. Surface water peroxide concentrations increased follo wing an evening rain shower and remained elevated by about 40 nM throu ghout the remainder of the study. Atmospheric input of H2O2 appears to represent a disturbance to the kinetic balance of H2O2 production and loss and thus produces long term H2O2 trends while the system approac hes the steady state concentrations dictated by mixing regime and in s itu processes. Vertical profiles showed H2O2 distributions which close ly follow density profiles with concentrations dropping rapidly to les s than 5 nM below the thermocline when a distinct seasonal mixed layer was present. Results suggest H2O2 as a useful tracer for freshwater i nput and mixing processes in the upper ocean.