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 mechanism causes reduced sediment deposition rates within an oxbow lake compared to the active river channel?
• Which risk increases along strike-slip faults connecting seafloor spreading centers?
• Which outcome follows reduced wave refraction around stacks?
• Which outcome occurs when atmospheric high-pressure systems intensify over subtropical ocean gyres?
• Which outcome follows strengthened trade winds in the Pacific?
• Which phenomenon occurs when localized offshore winds consistently displace surface waters away from mountainous coastal regions?