Suspended particulate matter concentrations and organic matter fractions from water samples

This dataset comprises results from filter weights of more than 5000 water samples taken during numerous field surveys between 1998 and 2017 in the Odra Lagoon (German Baltic Sea coast), several parts of the German Wadden Sea, the Exclusive Economic Zone of Germany in the German Bight (Southern North Sea), the Limfjorden (Denmark), the Oosterschelde (The Netherlands) and the Ria de Vigo (Spain). From the filter weights and filtered water volumes the suspended particulate matter concentrations (SPMC) and, in most cases, the fractions of organic matter were determined by combustion of the loaded filters (Loss on Ignition - LoI). Over the years, the laboratory methods and the type of filter (Whatman GF/C glass fibre filter, 47 mm diameter) were kept identical, but the sampling methods were adapted to technical demands, to the specific conditions of the sampling areas and to novel methodological insight. The samples had to undergo a number of quality checks regarding sampling time and co-ordinates and all laboratory processing steps. Depending on which test they passed they were assigned two types of quality flags, for (1) space and time information and (2) for the sample itself. They range from 1 ("good": all tests passed) to 4 ("bad and not correctable"); further, 9 is assigned for cases with missing information of time, latitude/longitude or water pressure. Further, the filter weights were corrected for filter offsets and - when Loss on Ignition was also determined - for losses of structural water.