Overview
- Researchers at Germany’s Thünen-Institut synthesized 88 long-term datasets, some spanning up to 75 years, and found abrupt ecosystem shifts in 2003 or shortly afterward.
- The event combined a weakened subpolar gyre with a strong northward push of subtropical water, reduced southward Arctic flow, and exceptionally high air temperatures.
- Early impacts hit the food web base as Arctic zooplankton declined and warm-water taxa expanded, followed by northward shifts in species such as cod and haddock and a damaging relocation of capelin spawning grounds.
- Heat anomalies penetrated to roughly 700 meters and reached the seafloor years later in regions like the Fram Strait, reshaping benthic communities and lowering the nutritional quality of sinking biomass.
- Fisheries moved grounds and tactics as some catches rose (notably haddock) and others fell, and later warm years failed to trigger comparable system-wide reorganizations without the same compound drivers.