Which process MOST directly maintains the high nutrient concentration within oceanic gyre boundary currents?

💡 Explanation

When surface waters converge due to Ekman transport, downwelling occurs, concentrating nutrients towards the lower layers of the gyre boundary. Therefore Ekman transport convergence maintains the nutrient level, rather than dissipation, mixing, or tidal resonance which have less significant roles.

• Which outcome primarily results when tectonic subsidence forms a deep lake basin in a humid region?
• Which mechanism sustains high sinuosity in meandering streams within humid continental regions?
• Which outcome results when a lava dome's flank destabilizes?
• Which mechanism causes volcanic arc formation parallel to a subduction zone when a slab hydrates mantle?
• Which mechanism contributes to the oxygen stratification observed in deep fjords containing density gradients?
• Over-irrigation in arid land increases risk of which pedogenesis outcome?