The input of nutrients is a relatively important pressure in coastal areas, particularly off areas of intensive agriculture and certain industries. Rivers account for most waterborne inputs of nitrogen and phosphorous. There is no clear trend in nitrate inputs in this region, in contrast to the decreasing trends in other EU waters. Maritime transport, international shipping, and aquaculture also contribute to this pressure.
Tourism and recreation along the coast is increasing in many parts of the ecoregion and seasonal management of the extra waste water produced is necessary. Eutrophication is mainly limited to coastal areas such as bays and estuaries with restricted circulation. Along the French coast, elevated levels of chlorophyll, nuisance phytoplankton species, and algal toxins have been observed.
This pressure produces effects on the plankton community and on the overall productivity of the system.