The marine biome covers most of the earth and contains thousands of species of plants and animals. It has three vertical zones - the euphotic, dysphotic, and aphotic layers - with temperatures varying from cold on the bottom to warmest at the top. Weather and climate affect the habitat. Key locations include the Indian, Atlantic, Arctic, and Pacific Oceans. Common plants include various algae and fan plants, while animals include fish, jellyfish, dolphins, whales, seals, and more. The food chain starts with phytoplankton and zooplankton feeding small fish and bigger fish that in turn feed mammals.