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absorbance spectra, flourescence spectra, Lake Louise, excitation-emission matrix spectra


(Files are available for download below.)

Macrophytes are a potential source of dissolved organic matter (DOM) in lakes. To probe the contribution of Nymphaea odorata (lily pads), dissolved organic carbon concentrations (DOC) and optical properties of chromophoric DOM were measured in a lake in the Pacific Northwest, United States over a year. Lily pads are prevalent around the shoreline during summer, dying back in fall. Indices of recent autochthonous contribution (BIX), fluorescence (FIX) and SR showed the lake was dominated by terrestrially-derived material. DOC concentrations were not correlated with rainfall, but were positively correlated with absorption coefficients. Values were highest in the summer dry season and decreased in the winter wet season, suggesting a source in the lake being diluted by precipitation rather than a dominant source from watershed runoff. Humic-like and protein-like fluorescent components were identified from excitation-emission matrix spectroscopy in lake waters and lily pad leachates. The protein-like component was highest during the summer, indicative of an in situ autochthonous source. Lily pad leachates had BIX, FIX, and SR values characteristic of terrestrial material and lake samples. However, leachates had lower humification index (HIX), specific ultraviolet absorbance (SUVA), flu/abs ratios and spectral slope (S) values. Higher absorption coefficients and DOC concentrations in the lake in summer were correlated with lower HIX, SUVA, flu/abs and S values, consistent with material leaching from lily pads. Seasonal trends in optical indices, absorption coefficients and DOC concentrations are consistent with lily pads being a significant DOM source in the lake, particularly in the summer dry season with low watershed runoff.

This is for the supporting data for the paper in Limnology and Oceanography, specifically the absorbance and fluorescence spectra of the Lake Louise water samples (taken weekly over the course of a year). These files include large spreadsheets with raw and corrected absorbance and fluorescence intensity data as a function of wavelength, as well as the raw and corrected absorbance and fluorescence 3D excitation-emission matrix spectra (EEMs). These files are in .opj format, which is readable with commercially available Origin graphing software.





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