Publication Date:
2016-02-26
Description:
The Swedish Coastal zone Model (SCM) was used at a test site, the Stockholm Archipelago located in the northern part of the central Baltic Sea, to study the capacity of the coastal filter on nitrogen (N) and phosphorus (P). The SCM system is based on the Swedish Coastal and Ocean Biogeochemical model (SCOBI) coupled to the equation solver PROgram for Boundary layers in the Environment (PROBE). In this study the Stockholm Archipelago consisting of 86 sub-basins was divided into three sub-areas: the inner, the intermediate and the outer archipelago. An evaluation of model results to observations showed that the modelled freshwater supply and the nutrient, salinity and temperature dynamics in the SCM model are of good quality. Further, the analysis showed that the Stockholm Archipelago works as a filter for nutrients that enter the coastal zone from land, but the filter capacity is not effective enough to take care of all the nutrients. However, at least 65 % and 72 % of the P and N, respectively, are retained. Highest total amounts of P and N are retained in the outer archipelago where the surface area is largest. The area weighted specific retention of P and N, however, is highest in the smaller inner archipelago and decreases towards the open sea. A major part of the retention is permanent, which for P means burial. For N almost 92 % of the permanent retention is represented by benthic denitrification, less than 8 % by burial, while pelagic denitrification is below 1 %. A reduction scenario of the land loads of N and P showed that the retention capacities of N and P increase and the export of N from the archipelago decreases. About 15 years after the reduction the export of P changes into an import of P from the open sea to the archipelago.
Print ISSN:
1810-6277
Electronic ISSN:
1810-6285
Topics:
Biology
,
Geosciences
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