Using a conversion factor of 50, as applied by Hoppe et al. , the average phytoplankton carbon biomass
of 55 mg/m3 corresponds to a chl.a concentration of 1.1 mg/m3. This concentration meets the suggested target of 1.3 mg/m³ chl.a very well. TN and TP reference and target concentrations (annual near surface averages) for all German Baltic water bodies are documented in Appendix A1 and A2 and some results are summarized in Table 1. The existing ATR inhibitor target values for TN and TP for inner coastal waters (types B1 and B2) of Brockmann et al.  are in most cases and of Sagert et al.  for several water bodies unrealistic low because they do not take into account the individual situation of each water body. Both approaches suffer from
several weaknesses. (a) the riverine loads in Brockmann et al.  calculated with MONERIS did not reflect a real historic situation but assume artificial background concentrations and loads; (b) the natural gradients of nutrient concentration between river and open sea and especially the role of inner coastal waters as retention and transformation units for nutrients calculated by Brockmann et al.  are neglected; (c) hydrodynamic processes and spatial transport in the Baltic sea as well as the exposition MK-2206 supplier of water bodies towards pollution sources are neglected and finally, (d) explicit assumptions concerning the nutrient loads from neighboring states and other Baltic regions are lacking. For Bornholm Basin, Arkona Basin and Danish Straits, Carstensen et al.  suggest chl.a target concentrations of 2.44; 1.89 and 1.44 mg/m³ chl.a. Spatially integrating our results over the surface area of these Baltic Sea basins, we receive similar concentrations of 1.97 (Bornholm Basin), 1.79 (Arkona Basin) and 1.56 mg/m³ chl.a (Danish straits). Therefore, the proposed target values for the western Baltic Sea by Carstensen et al.  are largely confirmed (Table 1, Fig. 7). The small difference can Edoxaban be largely explained by
the different approaches and differences in the considered period for the analysis. Not for all water body types the calculation of DIN and DIP winter reference and target concentrations the methodology described above (multiplication of a factor with present data) provided convincing results, when compared to data (Fig. 9). This is especially true for inner coastal waters (types B1 and B2). As an alternative, DIN and DIP winter target concentrations were calculated based on average annual TN resp. TP concentrations. For every water body sub-type a separate linear regression between winter DIN (DIP) and average annual TN (TP) was established with the following coefficients of determination (R²) for the sub-water body types: B1 0.28; B2a 0.35; B2b 0.74; B3a 0.39; B3b 0.73; B4 0.59. In outer coastal waters and the open sea both methods show comparable results.