Absorption measurements of Nodularia spumigena bloom from Lake Bante In Wilhelmshaven, Germany

We derived the absorption coefficients (m-1) from 400 to 700 nm at 2 nm resolution of surface water samples from the German Lake Bante in Wilhemshaven. The water samples were analyzed for the total absorption coefficients of the unfiltered water (a_tot) and colored dissolved organic material (a_cdom) after filtration using a membrane filter of 0.2 µm pore size. Absorption coefficient of algal material (a_ph) was computed as the difference between a_tot and a_cdom under the assumption that no contribution was expected from suspended particulate solids. Absorption coefficient measurements were conducted in a point-source integrating-cavity absorption meter (PSICAM) with a sample chamber volume of ~400 mL. Information about the PSICAM measurements, calibration of the instrument and data correction are explained more in literature (Leathers et al., 2000; Röttgers et al.,2007). Raw data is available upon reasonable request from the authors.