Date: May 17, 2018
Source: CNRS
Several ocean cycles, such as the
El Niño phenomenon, occur in the Pacific ocean and have climatic repercussions
around the globe (e.g. intense rains in South America, mild winters in Canada,
etc.) However El Niño (with a periodic oscillation of 2 to 7 years) is not the
only natural and cyclical variation observed in the Pacific: the Pacific
decadal oscillation (PDO) is a variation in surface water temperatures which
causes significant changes in sardine and anchovy population sizes due to
upwelling, a process in which nutrient-rich deep ocean water rises to the
surface.
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