Marine biologist
A biologist studies all life forms.
scientist
An Ecologist is a scientist who studies ecosystems.
If you are meaning the light spectrum, Physicists study all forms of light and waves and what they do.
a type of scientist who studies about metal is called metallururgist
what is the scientist that studies motions? A Physicist
oceanographers DarkFoxy: and marine biologists or is that the same thing.... well either way its another term
A mineralogist studies minerals.
An ecologist studies pollution
The kind of scientist who studies Urology would be a Biologist, since Urology concerns a biological function (urination). If you mean the kind of doctor who studies Urology, that would be a Urologist.
meteoroligists
An Ichthyologist.