OceanWorld

Topic: El Niño
Theme: Interactions

Key Concepts:

Fisheries

  • El Niño dramatically reduces primary productivity in the eastern coastal equatorial Pacific region, along the coast of Peru, because upwelling is inhibited.
  • Phytoplankton populations, nourished by the nutrients brought up through upwelling. are reduced. As the phytoplankton diminish, the anchovy population that feeds on them declines dramatically and the fish disperse (move away).
  • El Niño's warm waters also destroy coral reefs in tropical areas that are accustomed to cooler waters. The temperatures bleach the coral reefs and destroy the animals that inhabit the reefs and rely on them for survival.
  • Along the Peruvian coasts, huge populations of birds died with the disappearance of the anchovy.

Coastal Destruction

  • Due to the rise in sea temperature during an El Niño, the southwestern coast of North America, especially California, receives higher than normal precipitation and storms. This excess of rain leads to destructive landslides.

Less Atlantic Hurricanes

  • Hurricanes develop over warm, tropical ocean areas where a low-pressure zone develops. These low-pressure zones draw air inward across the ocean surface. If the conditions are right, the low-pressure zone deepens and a hurricane may form.
  • Under El Niño conditions, less hurricanes form in the Atlantic because of changes in the tropical atmosphere.