Freshwater DOM quantity and quality from a two-component model of UV absorbance
Water Research
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Abstract
We present a model that considers UV-absorbing dissolved organic matter (DOM) to consist of two components (A and B), each with a distinct and constant spectrum. Component A absorbs UV light strongly, and is therefore presumed to possess aromatic chromophores and hydrophobic character, whereas B absorbs weakly and can be assumed hydrophilic. We parameterised the model with dissolved organic carbon concentrations [DOC] and corresponding UV spectra for c. 1700 filtered surface water samples from North America and the United Kingdom, by optimising extinction coefficients for A and B, together with a small constant concentration of non-absorbing DOM (0.80 mg DOC L-1). Good unbiased predictions of [DOC] from absorbance data at 270 and 350 nm were obtained (r2 = 0.98), the sum of squared residuals in [DOC] being reduced by 66% compared to a regression model fitted to absorbance at 270 nm alone. The parameterised model can use measured optical absorbance values at any pair of suitable wavelengths to calculate both [DOC] and the relative amounts of A and B in a water sample, i.e. measures of quantity and quality. Blind prediction of [DOC] was satisfactory for 9 of 11 independent data sets (181 of 213 individual samples).
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Freshwater DOM quantity and quality from a two-component model of UV absorbance |
| Series title | Water Research |
| DOI | 10.1016/j.watres.2012.05.021 |
| Volume | 46 |
| Issue | 14 |
| Year Published | 2012 |
| Language | English |
| Publisher | Elsevier |
| Publisher location | Amsterdam, Netherlands |
| Contributing office(s) | Utah Water Science Center |
| Description | 11 p. |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Water Research |
| First page | 4532 |
| Last page | 4542 |
| Google Analytic Metrics | Metrics page |