Storage experiment for the analysis of dissolved organic matter in surface water and groundwater

This dataset contains the data resulting from a storage experiment, whereby samples from surface water (n=3) and groundwater (n=1) were stored cooled (4°C) or frozen (-20°C) and analysed after 1, 2, 3, 7, 14, 30 and 90 days using fluorescence spectroscopy (Aqualog, Horiba Scientific, Edison, NJ, USA). For each sample, the absorbance spectrum (240–500 nm) and a fluorescence excitation-emission matrix (EEM) were obtained. EEMs were obtained for excitation wavelengths 240–500 nm (3 nm interval) and emission wavelengths 248–825 nm (~4.6 nm interval) with an integration time of 1 second. Five absorbance indicators and eight fluorescence indicators were calculated. The DOC concentration was estimated using the two-wavelength approach of Cook et al. (2017).

The dataset consists of four files:

• Aqualog data processing and index calculation.R: R script with the code to process the Aqualog data and to calculate the indices.
• Aqualog.zip: Raw data obtained from the Aqualog, divided into subfolders corresponding to the day of measurement. For each sample, the absorbance spectrum (*ABS.dat) and EEMs of the sample (*SEM.dat) and corresponding blank measurement (*BEM.dat) are provided.
• Indices.xlsx: Table with index values for all samples.
• Samples.xlsx: Table with information about all samples (e.g. sampling site, storage duration, storage method)

The geolocations of the sampling sites are:

• Site 102 - 50° 29' 6.09''N - 8° 33' 33.57''E
• Site 134 - 50° 28' 36.55''N - 8° 32' 39.56''E
• Site 175 - 50° 28' 34.05''N - 8° 32' 42.89''E
• Site 187 - 50° 28' 49.98''N - 8° 32' 35.12''E