Raw absorbance and fluorescence measurements of water samples during Nodularia spumigena 2021 bloom event on Lake Bante in Wilhelmshaven, Germany

Water sampling was conducted from the shoreline of Lake Bante in Wilhelmshaven, Germany. A very dense Nodularia spumigena bloom was taking place on the day of sampling 16 August 2021. Samples were kept in the dark and stored at 4 °C until further analyses were conducted. First the samples were pre-filtered through Whatman GF/F filters with a 0.7 µm mesh. Further filtration was done using Whatman Nuclepore Track-Etch 0.2 µm pore size membranes within 72 hours after field sampling. Sample filtrate was diluted using deionized water at a ratio 1:4 to mitigate inner filter effect and detector saturation. Excitation-emission matrices (EEMs) and absorbance measurements were done using a Horiba Aqualog benchtop fluorometer. Sample filtrate was placed in a 1 cm quartz cuvette that had been pre-rinsed 3 times before each measurement.