Which mechanism causes low-nutrient conditions in subtropical ocean gyres, due to subsidence within Hadley cells?

💡 Explanation

When air descends within Hadley cells, convergence occurs causing thermocline depth shoaling because downwelling suppresses vertical mixing preventing nutrient replenishment from below. Therefore convergence inhibits vertical mixing rather than upwelling, river runoff, or meltwater contributions, processes which would increase nutrient levels.

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