fig. 2.27 > To reduce eutrophication in the Baltic, HELCOM, an intergovernmental marine protection commission, has divided the Baltic Sea into subregions, each of which was assigned an individual maximum allowable level of nitrogen inputs (left). German scientists criticized that these maximum allowable inputs do not consider small-scale variations in natural nutrient concentrations between various types of coastal waters such as inlets (bodden) or fjords. To address this issue they calculated small-scale, spatially differentiated thresholds for nutrient inputs (bottom). The figures above show recommended thresholds for the summer period. The figures do not reference maximum nitrogen loads but maximum levels in chlorophyll values, i.e. thresholds for algal concentrations which in turn are influenced by nutrient loads. © Friedland/IOW, maribus