Report: LAWA: Structure Matrix water types WRRL North Sea — Weser and Elbe. Final Report Part A (2007)»

“Summary: Nutrients: For the coastal and transitional waters of the German North Sea coast, BROCKMANN et al. (2004) Total nitrogen reference values (TN), dissolved inorganic nitrogen (DIN), nitrate (NO3), total phosphorus (TP) and phosphate-P (PO4-P) based on historical and model data. The starting point for the definition of class boundaries according to WFD was the classes “Non Problem Area” and “Problem Area” distinguished in OSPAR (EUC 2005) from which the five-level classification could be derived according to WFD. A corresponding assessment of the current nutrient ratios in the individual water bodies based on the existing data sets is only unsatisfactory (NEA1-Weser, NEA2-Weser, NEA3-Weser, NEA1-Ems, NEA2-Ems, NEA4-Ems) and bad (NEA11-Ems, NEA11, Weser, NEA3-Ems, NEA4-Weser) classifications. Another parameter is the average ratio of nutrients nitrogen and phosphorus to each other (N/P ratio), but a classification system has not yet been established. Fish: On behalf of the Länder of Lower Saxony and Schleswig-Holstein, BIOCONSULT (2006) prepared a multimetric evaluation process that takes into account the aspects of species spectrum, abundance and age structure of the fish fauna of the transitional waters and is based on a historical reference cenosis. The processing was carried out for the estuaries Ems, Weser, Elbe and Eider. BioConsult (2006) developed a computer-aided evaluation tool based on a database containing historical and up-to-date species-specific characteristics such as membership of user, habitat and reproduction guilds, species-specific frequency, etc. Current catch data can be fed in using an input mask. The evaluation is carried out by the programme taking into account the measures developed in the project (Metrics). BioConsult selected ten valuation-relevant metrics for the evaluation system as well as the additional evaluation parameter “disturbance”, which, as a special representative of a very good condition of the estuary, may be included in the evaluation system. The metrics evaluate the state of selected ecological guilds (hiking species, estuarine species, marine species) and the abundances of selected species (caulfish, finte, stint, flounder, caster belly, herring). The aspect of the age structure is included in the evaluation concept by evaluating the occurrence of juvenile stages of Finte and Stint. This species spectrum can be specifically adapted for the estuary to be evaluated. It is not for each assessment criterion that a classification in one of the five ecological status classes takes place separately, but points are awarded for certain characteristics, from which a total value is then calculated using a formula that represents a specific ecological state. The evaluation system for fish in transitional waters of the North Sea, developed by BIOCONSULT (2006), is considered conclusive in the scientific college and is coordinated with the colleagues from Schleswig-Holstein and Hamburg. The evaluation system was also presented at international level as part of intercalibration and there is close cooperation through data exchange and joint projects as well as bilateral intercalibration with the Netherlands. Phytoplankton: The evaluation system for the quality component phytoplankton in the coastal waters of the German North Sea includes the parameters “mean chlorophyll a-content of the growing season”, “Chlorophyll a-annual maxima”, “total biovolume”, “biovolume of biddulphials”, “flower frequency of Phaeocystisspp.” and “potential pointer species”. As an additional criterion, the nutrient situation should be included in the evaluation of the phytoplankton. For the transition waters, the phytoplankton is due to the high suspended concentrate_CUTABSTRACT_