Marine Ecosystems and Diversity

Marine EcosystemsMarine ecosystems are habitats that are classified within aquatic ecosystems. They include the oceans, seas and marshes among others water bodies. Life as we know it arose and evolved in the sea. The marine environment is rather stable when compared to terrestrial and freshwater habitats. Temperatures in large oceanic masses vary little, as does the water salinity (which is about 3.5%). The ionic composition of seawater is similar to the body fluids of most marine organisms. This is a key element in the process of osmotic regulation.

Sunlight penetrates water only about 200 meters deep in the ocean environment. At greater depths, there is absolute darkness. The illuminated area of the sea is called “photic region”, while the dark zone is called “aphotic region”. In the ocean, there is a great distance between the photic zone (near the surface) and the place where most nutrients (accumulated in deep water) can be found. Where light reaches and facilitates its production, there are some inorganic nutrients but not nearly enough to ensure survival of the many species that inhabit the vast ocean world. It is no wonder, then, that the areas with higher productivity or fertility are those found in deep, cold and nutrient laden waters.

Marine ecosystems are, naturally, the biggest on planet Earth when compared with other aquatic ecosystems. Among them can be included ecosystems such as inter-tidal zones, salt marshes, estuaries, mangroves, lagoons, coral reefs, the deep sea and last but not least, the sea floor. Freshwater ecosystems, on the other hand have a much lower salt content. The ocean covers three quarters of the total surface of planet Earth. Ecosystems are defined by the fact that its plant life can support animal life and other way around. Marine ecosystems are of utmost importance for the health of Earth’s environments (both marine and terrestrial).