The Subtropical Gyre influences the southernmost waters of the ecoregion, where surface conditions have recently been warmer than average. In recent years, however, there has been a persistent cold anomaly in the Subpolar Gyre. The subpolar cold anomaly increased in size and intensity during 2013–2015 when it exceeded 2°C below average, but since 2016 it has diminished in intensity (by around 1°C) and areal extent. Since 2014 the surface temperature anomaly has been accompanied by a near‑surface low salinity anomaly along the Greenland coast in both the Labrador and Irminger basins. The low salinity near‑surface water may be a result of increased precipitation and of Greenland ice sheet melting.
Phytoplankton pigment concentrations, estimated from satellite data (1998–2017) and Continuous Plankton Recorder (CPR) Phytoplankton Colour Index data (1958–2017), suggest that phytoplankton biomass is greater now than in the previous 20 to 60 years. These pigment trends, however, are not matched in the major plankton group abundances. This suggests that micro-phytoplankton communities (those not caught by the CPR) may be contributing to the pigment concentration increases. CPR diatom and dinoflagellate abundances (1958–2017) were increasing in the far western part of the ecoregion but decreasing in the east, with no long-term trend in the central areas.