Marine Biology

Marine biology is the scientific study of living organisms in the ocean or other marine or brackish bodies of water.

World Marine Environment.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 differs from marine ecology as marine ecology is focused on how organisms interact with each other and environment and biology is the study of the animal itself.

Marine life is a vast resource, providing food, medicine, and raw materials, in addition to helping to support recreation and tourism all over the world. At a fundamental level, marine life helps determine the very nature of our planet. Marine organisms contribute significantly to the oxygen cycle, and are involved in the regulation of the earth's climate.

Shorelines are in part shaped and protected by marine life, and some marine organisms even help create new land.

Marine biology covers a great deal, from the microscopic, including most zooplankton and phytoplankton to the huge cetaceans (whales) which reach up to a reported 48 meters (125 feet) in length.

The habitats studied by marine biology include everything from the tiny layers of surface water in which organisms and abiotic items may be trapped in surface tension between the ocean and atmosphere, to the depths of the abyssal trenches, sometimes 10,000 meters or more beneath the surface of the ocean. It studies habitats such as coral reefs, kelp forests, tidepools, muddy, sandy and rocky bottoms, and the open ocean (pelagic) zone, where solid objects are rare and the surface of the water is the only visible boundary.

A large amount of all life on Earth exists in the oceans. Exactly how large the proportion is still unknown. A lot of species living in oceans are still to be discovered. While the oceans comprise about 71% of the Earth's surface, due to their depth they encompass about 300 times the habitable volume of the terrestrial habitats on Earth.

Many species are economically important to humans, including food fish. It is also becoming understood that the well-being of marine organisms and other organisms are linked in very fundamental ways. The human body of knowledge regarding the relationship between life in the sea and important cycles is rapidly growing, with new discoveries being made nearly every day.

These cycles include those of matter (such as the carbon cycle) and of air (such as Earth's respiration, and movement of energy through ecosystems including the ocean). Large areas beneath the ocean surface still remain effectively unexplored.

Ocean Life and Resources

A rich variety of resources, both organic and inorganic, exists below the surface of the sea. Here, a young turtle makes its way through a living labyrinth built by coral and other organisms on the rocky ocean floor.

Estimates indicate that the ocean is capable of producing as much as 200 million metric tons of harvestable organic matter and may contain more than 10 billion tons of gold. The only difficulty in tapping these resources is the complex interrelationship between the chemistry, geology, and physics of the sea.

It is nearly impossible to alter one without impacting the others.

Vertical Ocean Circulation

The predominant circulation patterns in the open ocean are horizontal ocean currents that affect the upper surface waters, but the vertical circulation of open ocean water masses may be more important for marine life. The nutrient-rich waters encourage the growth of plankton, which serves as the base for the food chain throughout the oceans.

In thermohaline circulation, differences in the temperature, density, and salinity of ocean water masses cause the nutrient-rich deep ocean waters to rise and mix with surface waters. Thermohaline circulation is restricted to polar regions of the northern and southern hemispheres.