among the red, green and brown algae that inhabit the sea, which is likely to be found in the deepest waters? why?

Red algae are able to grow in depth of seas as compared to green algae because of the presence of more quantity of pigment phycoerythrin in red algae growing at depth. Phycoerythrin can absorb blue- green wavelength of visible spectrum of light that can  reach the maximum depth of water and help in photosynthesizing those red algae .