The Marine biome is the largest biome on our planet because the majority of our world is covered by water. The vast oceans contain a great variety of life that we have only scratched the surface of. In fact the majority of the oceans still remain unexplored.
Oceans range from deep to shallow waters and the types of creatures change from one level to the next. Tides raise and lower the water level near the shore, changing the community from one time of day to another. Along rocky shores a vast difference can be seen in the high tide and low tide creatures. The further from shore one gets the deeper the water can be, heading into the open ocean.
Coral reefs occur in warm shallow waters and support a large number of animals, the majority of which are coral. Coral is interesting in and of itself, as it is an animal.
Estuaries are places where freshwater and ocean water meet and mix. Here there is often a high variety of animal life and many fisheries occur around them. Many types of ocean creatures need estuaries to reproduce. Estuaries often are the basis of many wetlands at the mouths of rivers spilling into the ocean.