Which phenomenon significantly reduces primary productivity when El Niño disrupts equatorial ocean circulation?

💡 Explanation

When El Niño occurs, trade winds weaken, causing the thermocline to deepen along the equatorial Pacific because reduced upwelling of nutrient-rich deep water occurs. Therefore thermocline deepening and limited upwelling reduce primary productivity, rather than dilution, cloud cover, or plankton dispersal which are secondary effects.

• Which geological outcome primarily causes terracing in periglacial environments exhibiting solifluction?
• Which volcanic outcome characterizes subduction beneath continental crust?
• What fallout risk increases downwind following explosive Hawaiian-style volcanic activity?
• Which outcome is accelerated by increased saturation during subduction?
• In a closed-basin desert lake, which process limits the maximum salt concentration?
• Which mechanism dictates volcanic eruption explosivity when magma's silica content rises above approximately 65%?