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<p>Temporal variations in excess nitrate (DIN<span class="inline-formula">_{<i>x</i><i>s</i>}</span>) relative to dissolved inorganic phosphorus (DIP) were evaluated using datasets derived from repeated measurements along meridional and zonal transects in the upper (200–600&thinsp;m) North Atlantic (NAtl) between the 1980s and 2010s. The analysis revealed that the DIN<span class="inline-formula">_{<i>x</i><i>s</i>}</span> trend in the western NAtl differed from that in the eastern NAtl. In the western NAtl, which has been subject to atmospheric nitrogen deposition (AND) from the USA, the subsurface DIN<span class="inline-formula">_{<i>x</i><i>s</i>}</span> concentrations have increased over the last 2 decades. This increase was associated with the increase in AND measured along the US East Coast, with a mean lag period of 15 years. This time lag was approximately equivalent to the time elapsed since the subsurface waters in the western NAtl were last in contact with the atmosphere (the ventilation age), suggesting a major role for a physical mechanism in transporting the AND signals to the subsurface. Our finding provides evidence that the DIN<span class="inline-formula">_{<i>x</i><i>s</i>}</span> dynamics in the western NAtl in recent years has been affected by anthropogenic nitrogen inputs, although this influence is weak relative to that in the western North Pacific. In contrast, a decreasing trend in subsurface DIN<span class="inline-formula">_{<i>x</i><i>s</i>}</span> was observed after the 2000s in the eastern NAtl, particularly in the high latitudes. This finding was not associated with the comparable decrease in AND from Europe. Other natural processes (a possible decline in tropical <span class="inline-formula">N₂</span> fixation and weakening of the Atlantic meridional overturning circulation) may be responsible, but lack of time-resolved data on <span class="inline-formula">N₂</span> fixation and meridional circulation is an impediment to assessment of these processes. Our results highlight the importance of both anthropogenic and natural forcing in impacting the nutrient dynamics in the upper NAtl.</p>