A warm anomaly in the upper ocean, colloquially named “the Blob,” appeared in the Gulf of Alaska during the calm winter of 2013–2014, spread across the northern North Pacific (NP) Ocean, and shifted eastward and onto the Oregon shelf. At least 14 species of copepods occurred which had never been observed in shelf/slope waters off Oregon, some of which are known to have NP Gyre affinities, indicating that the source waters of the coastal “Blob” were likely of both offshore (from the west) and subtropical/tropical origin. The anomalously warm conditions were reduced during strong upwelling in spring 2015 but returned when upwelling weakened in July 2015 and transitioned to downwelling in fall 2015. The extended period of warm conditions resulted in prolonged effects on the ecosystem off central Oregon, lasting at least through 2016. Impacts to the lower trophic levels were unprecedented and include a novel plankton community composition resulting from increased copepod, diatom, and dinoflagellate species richness and increased abundance of dinoflagellates. Additionally, the multiyear warm anomalies were associated with reduced biomass of copepods and euphausiids, high abundance of larvaceans and doliolids (indictors of oligotrophic ocean conditions), and a toxic diatom bloom (Pseudo‐nitzschia) throughout the California Current in 2015, thereby changing the composition of the food web that is relied upon by many commercially and ecologically important species.

Novel midwater ocean sampling shows that physiology dictates zooplankton distributions in submesoscale low oxygen features.

The Palmer Long Term Ecological Research study region west of the Antarctic Peninsula is experiencing warming and changing seasonal sea ice dynamics. Abundance patterns of 3 species of pelagic secondary producers were analyzed for trends, cycles, range extensions or shifts in the location of highest density, and for changes in population dynamics over a 16 yr period (1993−2008). Species analyzed represented different hydrographic regimes and are known to have contrasting responses to seasonal sea ice dynamics: krill Euphausia superba, seasonal sea ice zone; tunicates Salpa thompsoni, warmer waters with minimal sea ice; and larval Antarctic silverfish Pleuragramma antarcticum, cold continental shelf waters. Cycles were observed in grid-wide abundance and recruitment for E. superba. Maximum grid-wide densities did not decrease, but the location of highest densities shifted southward 200 km, away from Adélie penguin rookeries at the northern end. A distinct change post-1999 was apparent in the frequency of occurrence and abundance of S. thompsoni. Mixtures of krill and salps became common, but neither peak densities nor the frequency of peak years for salps increased. As with Antarctic krill, highest salp densities shifted southward alongshore. Larval P. antarcticum were abundant in the northern coastal region in the early 1990s, but virtually disappeared in that region after 1999/2000. Possible mechanisms underlying these observations include the southerly movement of the sea ice edge during spring, changes in proximity of source populations (salps), and changes in transport pathways (larval P. antarcticum). Patterns are compared to those in the SW Atlantic.