Jump to main content
Jump to site search

Issue 4, 2014
Previous Article Next Article

Wavelength and temperature-dependent apparent quantum yields for photochemical formation of hydrogen peroxide in seawater

Author affiliations

Abstract

Wavelength and temperature-dependent apparent quantum yields (AQYs) were determined for the photochemical production of hydrogen peroxide using seawater obtained from coastal and oligotrophic stations in Antarctica, the Pacific Ocean at Station ALOHA, the Gulf of Mexico, and at several sites along the East Coast of the United States. For all samples, AQYs decreased exponentially with increasing wavelength at 25 °C, ranging from 4.6 × 10−4 to 10.4 × 10−4 at 290 nm to 0.17 × 10−4 to 0.97 × 10−4 at 400 nm. AQYs for different seawater samples were remarkably similar irrespective of expected differences in the composition and concentrations of metals and dissolved organic matter (DOM) and in prior light exposure histories; wavelength-dependent AQYs for individual seawater samples differed by less than a factor of two relative to respective mean AQYs. Temperature-dependent AQYs increased between 0 and 35 °C on average by a factor of 1.8 per 10 °C, consistent with a thermal reaction (e.g., superoxide dismutation) controlling H2O2 photochemical production rates in seawater. Taken together, these results suggest that the observed poleward decrease in H2O2 photochemical production rates is mainly due to corresponding poleward decreases in irradiance and temperature and not spatial variations in the composition and concentrations of DOM or metals. Hydrogen peroxide photoproduction AQYs and production rates were not constant and not independent of the photon exposure as has been implicitly assumed in many published studies. Therefore, care should be taken when comparing and interpreting published H2O2 AQY or photochemical production rate results. Modeled depth-integrated H2O2 photochemical production rates were in excellent agreement with measured rates obtained from in situ free-floating drifter experiments conducted during a Gulf of Maine cruise, with differences (ca. 10%) well within measurement and modeling uncertainties. Results from this study provide a comprehensive data set of wavelength and temperature-dependent AQYs to model and remotely sense hydrogen peroxide photochemical production rates globally.

Graphical abstract: Wavelength and temperature-dependent apparent quantum yields for photochemical formation of hydrogen peroxide in seawater

Back to tab navigation

Publication details

The article was received on 15 Jan 2014, accepted on 19 Feb 2014 and first published on 19 Feb 2014


Article type: Paper
DOI: 10.1039/C4EM00036F
Author version
available:
Download author version (PDF)
Citation: Environ. Sci.: Processes Impacts, 2014,16, 777-791
  •   Request permissions

    Wavelength and temperature-dependent apparent quantum yields for photochemical formation of hydrogen peroxide in seawater

    D. J. Kieber, G. W. Miller, P. J. Neale and K. Mopper, Environ. Sci.: Processes Impacts, 2014, 16, 777
    DOI: 10.1039/C4EM00036F

Search articles by author

Spotlight

Advertisements