Land-based pollution involves a number of inter-related pressures such as eutrophication, hypoxia, turbidity, redox potential discontinuity, and various types of biological and chemical contamination.
Eutrophication is a common problem in all three seas considered. In the Baltic Sea it is mainly related to farming and managed forestry. In the Western Mediterranean Sea, eutrophic conditions are increasingly reported in the last decades in coastal and transitional waters, leading to dystrophic crises and benthic and fish kills. Some regions of the North Sea receive large quantities of anthropogenic nutrients through large rivers, and to a lesser extent from atmospheric deposition and discharges from plants that treat wastewater.
The main areas affected by hypoxia in the Mediterranean Sea are coastal zones and lagoons where environmental features are: low depth, high productivity, organic matter enrichment and low hydrodynamic forces. In the Baltic Sea hypoxia is widespread in large areas both in the open deeper parts and at coastal stations. A side effect is increased release of phosphorous from sediments, giving a feed back to eutrophication. In the North Sea, hypoxia can occur seasonally particularly under stratified conditions in areas with high rates of production by phytoplankton.
VECTORS results are of help in identifying causes and effects of land-based pollution and in suggesting priorities for management and prevention.