Marine biology is a huge field, given that a large (exactly how large is unknown at this point) porportion of all life on earth is contained in the oceans. Included in this are many species that are economically important to humans, including the food fishes.
Aspects of and problems in marine biology
Marine biology covers a great deal, from the microscopic plankton (with phytoplankton hugely important as the primary producers of the sea), to the huge cetaceans.
The study of marine biology obviously reserves a great deal of attention for the physical effects of continual immersion in the ocean, as well as for the ways that various oceanic properties changing affects marine life. How oceanic factors affect distribution of various organisms is also studied.
Recent marine biotechnology has focused largely on marine biomolecules, especially proteins, that may have uses in medicine or engineering.
An interesting branch of marine biology is aquaculture.
Marine environments are the home to many exotic biological materials that may inspire biomimetic materials.
History of marine biology
In recent times, marine biologists are trying to complete the mapping of underwater species with the help of modern techniques, which could help in exploring the deepest oceanic depressions in which it is supposed that new species could be found, eventually of potential great interest also for the theories on evolution.
Related fields
Marine biology is closely linked to both oceanography and biology. It also encompasses ideas from ecology. Fisheries science can be considered a partial offshoot of marine biology, as can marine conservation.
Institutions, well known journals, etc.
Many universities teach courses in marine biology.