## 3 Results
A comparison of normalized EEM spectra of the lab-based LS55 fluorometer with the corresponding nearest normalized Kallemeter-based EEM spectra at stations 12-15 (Figure 10; station 11 had no close match-up within a time frame of \(\pm\)1 h) shows good similarity for stations 14 and 15, where signal intensities are 5-times higher as compared to stations 12 and 13 (compare Figure 8). These lower concentrations of fluorescent organic matter at stations 12 and 13 were only resolved from the apparently more sensitive laboratory LS55 spectrofluorometer, thus illustrating the current limits of the 'Kallemeter' with respect to low concentrations and the effects of noise. Please note that we applied normalization to the EEM spectra to enable a comparison of spectra signatures measured, independent from the signal strength. A non-normalized set of 'Kallemeter' EEM spectra is provided in the appendix (Figure A3) showing for every fourth dataset (a) an EEM spectra with EX wavelengths 230-550 nm, \(\Delta\lambda\) = 10 nm, integration time of 60 s and two averaged scans, slit = 10 nm, EM wavelengths 189-990 nm, and (b) an emission scan with EM wavelengths 189-990 nm for 250 nm EX wavelength. These Kallemeter-based EEM spectra show an increase in fluorescence intensities inside Trondheimsfjord as compared to the coastal water conditions in the EM wavelength range from 400 to 550 nm. PARAFAC analysis of the lab-based LS55 spectrofluorometer EEM spectra from water samples gathered at different depths demonstrated the presence of three main components (C1, C2, and C3) in the water samples (Figure 11, top panel). These components were characterized by their excitation and emission pairs (EX/EM) as follows. Component (C1) corresponding to terrestrial humic-like peaks A\({}_{\rm C}\) and C, component (C2) corresponding to marine humic-like peaks A\({}_{\rm M}\) and M, and component (C3) corresponding to protein-like Tryptophan peak T, as suggested by [PERSON] [29]. The spectral composition of the recorded lab-based LS55 spectrofluorometer EEM spectra (provided in Table 2) shows that the fluorescent intensity of the peaks C1, C2, and C3 remains constant between the open ocean stations (ST11 and ST12) and the outer section of the fjord (ST13). Once the mid- and inner-part of the fjord was reached, we recorded a sharp increment (by a factor of 5) in the fluorescent intensity for the components C1 and C2 (ST14 and ST15), while C3 stays nearly constant. Performing PARAFAC analysis of the Kallemeter-based EEM spectra along the transect resulted in a model with two components validated (Figure 11, bottom panel). These components, even though influenced by the noisy EEM spectra that suited as model dataset, can be related according to their excitation/emission pairs to the presence of terrestrial humic-like peaks A\({}_{\rm C}\) and C, and marine humic-like peaks A\({}_{\rm M}\) and M. Although reasonable EEMS where produced by the 'Kallemeter', the presence of noise and suspended materials in the samples must be addressed in the future, in order to minimize the observed displacement on the peak's position. Figure 9: Comparison of extracted ‘Kallemeter’ bulk fluorescence signal against FerryBox FDOM Cyclops-7-U sensor (**left panel**) as well as the corresponding channel of the MatrixFlu-UV (**right panel**). Red lines represent the results of a linear regression. Figure 10: Normalized EEM spectra from lab-based water sample analysis with the LS55 laboratory spectrofluorometer (**left**) and nearby (match-up of \(\pm\)1 h) in situ measurements with the Kallemeter (**right**) for stations 12–15 of [PERSON] expedition HE491 along a transect from the coastal ocean into the Trondheimsfjord. Notice that FDOM intensity in stations 14 and 15 are 5-times higher compared to stations 12 and 13. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample Number** & **Station** & **Depth (m)** & **C1 (RU)** & **C2 (RU)** & **C3 (RU)** & **Date** \\ \hline  
\hline \hline \end{tabular}
\end{table}