Spectrophotometer data for calibration of HSI index of the varved sediment record (HZM19) from Holzmaar, Germany

To calibrate the hyperspectral imaging (HSI) index values from the sediments of Holzmaar (HZM19) to concentration, a spectrophotometrically measured pigment analysis (Butz et al., 2015; doi:10.1117/1.JRS.9.096031) was performed for 23 samples. These samples were selected to cover a wide range of pigment concentrations as documented by HSI scanning. Approximately 1 g of wet sediment was treated with 100 % acetone according to the method of Lami et al. (1994; doi:10.1007/BF00684032), and the extracts were measured with a Shimadzu UV-1800 spectrophotometer to obtain the mass concentration of Chl-a and Bphe-a in µg/g dry sediment using a mass extinction coefficient for Chl-a (Fiedor et al, 2002; doi:10.1562/0031-8655(2002)0760145POTBCS2.0.CO2) and for Bphe-a (Jeffrey and Humphrey, 1975; doi:10.1016/S0015-3796(17)30778-3).