Romanticism is a literary style that emphasizes Man vs Nature. The struggle is a universal one and an individual one. The idea that man can affect nature and nature can affect man is an integral part of romanticism. The story is told in such a way that it is difficult at times to tell which is happening at any given moment. Is man affecting nature, or is nature the dominant force after all?
With its emphasis on individualism, emotion, independence and spirituality, Romanticism is seen in the various parts throughout "Moby Dick." Ahab is in the thrall of battle against nature, it is him and the whale - no matter what. Emotions rage, and he attacks the sea as well as the great white "beast." No sacrifice is too great. He will sacrifice himself, his crew, and his ship in the pursuit of this spiritual quest he finds himself on in the story.
Another element of Romanticism is the graphic portrayal of the story in terms that force the reader to face all of the emotion and turmoil taking place on the page. Melville does exactly that in this epic tale.