Marine bioscience is the scientific study of marine life, organisms in the sea. 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. Marine biology is the study of marine organisms, their behaviours and interactions with the environment. Marine biologists’ study biological oceanography and the associated fields of chemical, physical, and geological oceanography to understand marine organisms. Marine biology is a very broad area, so most researchers select a particular area of interest and specialize in it. Specializations can be based on a particular species, group, behaviour, technique, or ecosystem. Molecular biology is a related area of specialization in marine biology. Researchers apply molecular techniques to many environments ranging from coastal marshes to the deep sea and to various organisms such as viruses, plants, and fish.