define marine biology
Wiktionary(0.00 / 0 votes)Rate this definition: marine biology(Noun) The branch of biology dealing with organisms that live in the sea. Marine biology. Marine biology is the scientific study of organisms in the ocean or other marine or brackish bodies of water. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather than on taxonomy.