For marine biology you would probably have to take 3 or 4 chemistry classes: general chem, biochem, organic chem, and maybe quantitative analysis. I doubt you would have to take p-chem for marine bio. Of course this all depends on what school you go to and their respective major requirements. If you have your eye on any specific school I would look into the requirements.
You may have to take one or two chemistry classes. So no no major in chem.
For marine biology you would probably have to take 3 or 4 chemistry classes: general chem, biochem, organic chem, and maybe quantitative analysis. I doubt you would have to take p-chem for marine bio. Of course this all depends on what school you go to and their respective major requirements. If you have your eye on any specific school I would look into the requirements.