Water samples were taken at the surface and the bottom in transects crossing the lake or coastal site from locations with observed erosion to presumably undisturbed locations. The water sampler (1.5 L Uwitec, Austria) was attached to a graduated rope, lowered by hand and filled twice. Combined water samples were transferred to 2 L Nalgene bottles, filled to the top and subsampled at the field station for further analysis.Water samples for colored dissolved organic matter (cDOM) were filtered through a pre-rinsed disposable syringe with a GF/F filter of 0.7 μm pore size. For cDOM, about 40 ml of filtrate was filled into dark glass bottles and placed in cool storage. Absorption by CDOM was measured at the German Research Centre for Geosciences (GFZ), Potsdam, Germany using a LAMBDA 158 950 UV/Vis (PerkinElmer). The median absorbance of three replicate measurements was used to calculate the absorption. Fresh Milli-Q water was used as reference.