Anthony Vodacek


This article may be accessed from the publisher's website (additional fees may apply) at: The variation of freshwater chromophoric (or colored) dissolved organic matter (CDOM) fluorescence with respect to sample pH was examined. Trends from previous studies are supported by results obtained from fluorescence spectra collected during sample titration. The evidence suggests spectral variation of CDOM fluorescence can arise from pH-dependent photo-oxidation of a portion of the catechol component of CDOM to coumarin structures. A hypothesis is drawn that the observed shorter wavelength fluorescence exhibited by acid lake samples relative to the spectra of more neutral lake samples is, in part, a result of the inhibition of CDOM photo-oxidation under the acid condition. By careful choice of both excitation and emission wavelengths, fluorescence measurements may monitor changes in the composition of CDOM.

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I thank G. Bertolini, G.M. Ferrari, and D.W. van der Linde for their contributions to this work. The comments of two anonymous reviewers were helpful in revising the manuscript. Financial support for this work was provided by the Commission of the European Communities. Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

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Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)


RIT – Main Campus