Answer:
During an El Niño period, there is a weakening or even a reversal of the normal east-to-west trade winds across the tropical Pacific Ocean, which leads to a warming of the surface waters in the eastern Pacific. This warming disrupts the upwelling of cold, nutrient-rich water along the coast of South America, which has significant effects on marine ecosystems and climate patterns.
The lack of upwelling during an El Niño period can have several consequences, including:
1. Reduced productivity of marine ecosystems: The nutrient-rich waters that normally upwell along the coast of South America support a rich food web, including plankton, fish, and marine mammals. When the upwelling is disrupted, there is a reduction in productivity, which can lead to lower fish populations and even mass die-offs of marine life.
2. Changes in weather patterns: The warming of the eastern Pacific during an El Niño period can lead to changes in weather patterns around the world, including droughts, floods, and changes in temperature.
3. Economic impacts: The reduced productivity of marine ecosystems and changes in weather patterns can have significant economic impacts on communities that rely on fishing and agriculture.
In summary, the lack of upwelling during an El Niño period can result in reduced productivity of marine ecosystems, changes in weather patterns, and economic impacts on communities that rely on fishing and agriculture.