The input of nutrients is a relatively important pressure in coastal areas, particularly off areas of intensive agriculture and land‑based 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. Shipping, aquaculture, and increasing tourism and recreation along the coast also contribute to this pressure.
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.
