We used high-resolution paleoecological records of environmental change to study the rate and magnitude of

eutrophication over the last century in two contrasting coastal ecosystems. A multiproxy approach using geochemical

and biological indicators and diatom-based transfer functions provides a long-term perspective on changes in nutrient

concentrations and the corresponding biological and sedimentary responses. In Roskilde Fjord, Denmark, total

nitrogen (TN) increased 85% during the last century, with the most rapid increase occurring after the 1950s,

corresponding to the postwar increase in N fertilizer use. In Laajalahti Bay, an urban embayment near Helsinki,

Finland, total dissolved nitrogen (TDN) increased with growing wastewater inputs and decreased with the remedial

actions taken to reduce these discharges. These changes are small relative to the order of magnitude increases in

nutrient loading that have occurred in northwestern Europe, where the dissolved inorganic nitrogen (DIN) load has

increased more than threefold in certain areas.