Question

question 21
1 pts
the ekman spiral is caused by:
pressure gradients.
the wind and the coriolis effect.
density differences in the water column.
the pycnocline.
the wind and gravity.

Explanation:

The Ekman spiral is a phenomenon in oceanography. It is formed due to the interaction of wind stress on the ocean surface and the Coriolis effect (which is related to the rotation of the Earth). Wind drives the surface water, and as we go deeper in the water column, the Coriolis effect causes each layer of water to move at an angle to the layer above it, creating a spiral - like pattern. Pressure gradients are more related to geostrophic currents. Density differences in the water column and the pycnocline (a layer of rapid change in density) are related to thermohaline circulation. Gravity is a general force but not the specific cause along with wind for the Ekman spiral (gravity - wind interaction is more for other types of ocean movements like tides in a very general sense, but not the Ekman spiral).

Answer:

the wind and the Coriolis effect.