Among the red,green,brown algae that inhabit the sea , which is likely to be found in the deepest waters?
Red algae is mostly likely to be found in deep water.
Red algae is mostly likely to be found in deep water. This has to do with the different wavelengths of light and how deep they can penetrate water. Red light has the longest wavelength of the visible spectrum which means it penetrates water the least.
Anything red appears red because it reflects this wavelength. Thus, in deep water, red algae (and anything else that is red) appears black and is more difficult to see, making it harder for potential predators.
A relatively recent report on the deep water algae near Puerto Rico found that 60% of the algae are red, 29% green, and 11% are brown.
To learn more, there is a very good NOAA article written on why many deepwater creatures are red that can be found here.
You may also be interested in this related Socratic question, why can red algae live in deeper water than green algae?