Fluorescence peak locations (secondary peak in parentheses), representative EEMs, and spectral loadings of Phenformin three components identified by the PARAFAC model.ComponentExcitation maximumEmission maximumEEMSpectral loadings1240 (310) nm429.5 nm2240 (375) nm462 nm3270 (410) nm349.5 (> 600) nmFull-size tableTable optionsView in workspaceDownload as CSV
Fig. 8. Streams\' discharge (upper panel); fluorescence maximum (Fmax) of C1, C2 and C3 (middle panel), and the contribution of the three components to the total fluorescence (lower panel) in four Andean Patagonian streams. The arrow indicates the eruption of the Puyehue–Cordón Caulle volcanic complex on 4th June 2011.Figure optionsDownload full-size imageDownload as PowerPoint slide
3.4. Multivariate analysis: principal component analysis
The non-linear relationship between S275–295 vs. a350/DOC proposed by Fichot and Benner (2012) and used as a dual tracer of terrestrial DOM (high lignin content and high molecular weight) and photobleaching processing can be useful to situate the Andean streams in a wider environmental context. In this model, the Andean streams fall in the range of high molecular weight DOM with variable lignin content. This pattern reflects the influence of the inputs from the catchment, not yet transformed by photochemical processing. In fact, in first order streams traversing steep landscapes of the region, as is the case of the studied systems, the leaf litter is rapidly transported downstream thereby having a short residence time to allow leachate, and physico-chemical and biological degradation inside the streams ( Albariño et al., 2009), all processes known to affect DOM concentration and character ( Jaffé et al., 2008).