Radiolaria from equatorial regions found living in the Arctic Ocean in 2010. Top-bottom: Didymocyrtis tetrathalamus; Dictyocoryne truncatum; Zygocircus rhombus (Bjorklund et al., Jnl Micropalaeontology 2012)
That said, oceanographers have noted that such pulses seem to be coming more often and penetrating further—“exactly what one would expect from global warming,” saidRainer Froese, an oceanographer at the Helmholtz Centre for Ocean Research who tracks fish global populations. Could this be the start of a switch in currents predicted by climate models? The most recent pulse began in the early 1980s, and has lasted more or less to the present. Even without that, the arctic ocean itself is warming rapidly; with progressive loss of summer sea ice over past decades, average surface temperature has gone up as much as 5 degrees centigrade (9 degrees Fahrenheit) since 1950 in some patches.
Changes in global sea-surface temperatures, 1960s-2000s. Study area is near top, just to the right of center. (Sumalia et al., Nature Climate Change, 2011)
Researchers lower plankton-sampling nets into northern waters. (Beth Stauffer/Lamont-Doherty Earth Observatory)
©2013 - Polar Prince