Natural Organic Matter From a Norwegian Lake: Possible Structural Changes Resulting From Lake Acidification

A model for predicting dissolved organic carbon distribution in a reservoir water using fluorescence spectroscopy

“…The lower intensity of fluorescence indicates a lower degree of aromaticity for the HPINA fraction when compared to the other fractions. A peak for carboxylic acids at 310/400 (ex/em (nm)) was identified in the literature (Alberts, J. J. et al, 2000). A peak is observed in this region in the HPINA fraction EEM ( Figure 5).…”

“…It is this peak at the limit of observation that Marhaba, T. F. et al (2000) proposed as being representative of the organic matter in the sample. In a different study the two peaks observed were referred to as fluorescent pairs that were shown on the EEM as a bimodal peak distribution (Alberts, J. J. et al, 2000). In that study the second of the pairs was again at the edge of the observed excitation range.…”

“…The stronger intensity of fluorescence exhibited by the FAF (Figure 2), when compared to the HAF (Figure 3) (in the excitation area 300 -350 nm), indicated that smaller sized molecules fluoresce more strongly per mass of carbon. This could be as a result of more efficient energy transfer through internal conversions in the larger molecules (Alberts, J. J. et al, 2000). The presence of a variety of fluorescent structures has been reported as being indigenous in the fulvic macromolecule.…”

“…A peak is observed in this region in the HPINA fraction EEM ( Figure 5). This peak at 310/400 (ex/em (nm) is also said to be representative of small nitrogen containing compounds (Alberts, J. J. et al, 2000).…”