Resolving the variability in dissolved organic matter fluorescence in a temperate estuary and its catchment using PARAFAC analysis

Excitation emission matrix fluorescence spectroscopy combined with PARAFAC analysis provides a fast and effective method of characterizing the fluorescent fraction of dissolved organic matter (DOM). Fluorescence measurements can be used as a tracer for quantitative and qualitative changes occurring in the DOM pool as a whole. An earlier study found that the fluorescence signal could be modeled by five fractions. This study presents an analysis on a considerably larger data set (>1,200 samples) resulting from a 1‐yr sampling program in Horsens Estuary, Denmark. Eight fluorescent fractions were identified. Four biogenic terrestrial, two anthropogenic, and two protein‐like fractions were identified. Analysis of covariation between the components identified source‐specific fractions and the presence of common factors controlling the composition of terrestrial DOM exported from different catchments.