How is temperature affected when? (A) the depth increases (B) the latitude increases

(I) The deeper the waters, the lower the temperatures. This is because sunlight is unable to penetrate to deeper water because it gets attenuated due to diffusion and scattering. In addition, warmer waters are less dense and stay as surface waters.

(II) Temperatures of water are lower with increasing latitude. This is because of the differential angle at which sunlight hit the earth at different latitudes. At higher latitudes, the sunlight travels through a longer atmosphere hence become a bit attenuated before hitting the ground. In addition the surface area it 'hits' is larger than at lower latitudes.