Create a mask out of this layer: Layer – Add Layer Mask – Hide All and apply the Gradient Tool of white color to make the layer visible only on the bottom:

the little mermaid

Merge down the layers (ctrl+e) and increase the brightness of the new layer, applying
Image – Adjustments – Curves (ctrl+m).

the little mermaid

Finally we'll make the necessary correction on the color (Selective Color):

the little mermaid