What occurs when El Niño conditions last for an extended period?

When El Niño conditions last for an extended period, a decrease in primary production occurs primarily due to the warm ocean temperatures associated with this phenomenon. In typical conditions, nutrient-rich, cold waters rise to the surface, supporting a diverse array of marine life and fostering high primary productivity. However, during an El Niño event, the warm water signal leads to stratification of the ocean layers, which limits the upwelling of these nutrient-rich waters. Consequently, the phytoplankton that form the base of the marine food web struggle to thrive, resulting in reduced primary production. This decline can have cascading effects on the entire marine ecosystem, affecting species that rely on phytoplankton for food. Understanding the dynamics of primary production during El Niño is crucial to grasp the broader impacts on marine biodiversity and fisheries during prolonged events.