The Kuroshio, East Australia, and Gulf Stream currents lie on the eastern boundaries of these, while the California, Canary, and Humbolt Currents lie on their western boundary.
Karl et al. examined ecosystem changes in the North Pacific Subtropical one during the 1991-92 El Niño.  The Kuroshio, East Australia, and Gulf Stream currents lie on the eastern boundaries of these, while the California, Canary, and Humbolt Currents lie on their western boundary. The aforementioned currents and these (*) arise from the pressure gradient and Coriolis force and result in clockwise rotations in the Northern Hemisphere and counter-clockwise rotations in the Southern Hemisphere.  These large rotating centers have extremely low nutrient concentrations, and can give rise to abnormalities visible from trans-Pacific flights, the Great Pacific Garbage patch.  For 10 points, name these ogliotrophic, oceanic rotating systems that can be found in the middle of major ocean basins, once called "doldroms," a "widening" one of which appears in Yeats' Second Coming.
Karl et al. examined ecosystem changes in the North Pacific Subtropical one during the 1991-92 El Niño.  
oceanic {gyre} [prompt on early {current}s or {doldrom}s] (3) [MF]