The ecosystem consisting a group of interacting organisms dependent on each other and their water environments for nutrients and shelter is called an aquatic ecosystem. A type of aquatic ecosystem is known as marine ecosystem. It forms the largest part of this ecosystem. These systems include oceans, salt marshes, lagoons, coral reefs, the dep sea, etc. and have high salt content. The importance of marine biodiversity can be visualized from the fact that the sea waters cover about 71% of the Earth's surface and account for 99% of volume that is known to sustain life. [1]

The Indian ocean, Bay of Bengal, etc., form the marine ecosystems for India. In the coastal areas, the sea is shallow whereas at other places, it is very deep. There are invertebrates and millions of zooplanktons eaten by marine fishes and mammals. Near Kutch region, there are shallow areas. It is also found around Andaman and Nicobar Islands. Coral reefs are also found here. Fishes, starfish, jelly fish, crustaceans and polyps are a few of thousands of species found in these shallow areas. Coastal fisherfolk use this ecosystem for fishing, which is their livelihood. 

The coastal waters along the East and West Coast of the country and also around the two island groups have a plethora of marine species. The marine floral diversity includes 844 species of marine alga (sea weeds) belonging to 217 genera, 14 species of sea grasses and 69 species of mangroves. India’s marine fauna also holds a massive amount of diversity. The coastal waters of India harbour 451 species of sponges, more than 200 species of corals, more than 2900 species of crustacean, 3370 species of marine mollusks, more than 200 species of bryozoans, 765 species of echinoderm, 47 species of tunicates, more than 1300 marine fishes, 26 species of sea snakes, 5 species of sea turtles and 30 species of marine mammals including dugong, dolphins, whales etc. Additionally, an extensive diversity of sea birds can also be seen in India around its coast. [2]

There are mainly three types of coral reef formations-fringing reefs, barrier reefs and atolls. In India, all three types occur. Fringing reefs are found in Gulf of Mannar, Gulf of Kachchh and Andaman & Nicobar Islands. Barrier reefs are reported on the western side of Andaman group of Islands and atoll formations are common in Lakshadweep islands. A total of 199 species of corals belonging to 71 genera are recorded from Indian Ocean. A subsequent survey in Andaman group of islands by a team of UNDP and Indian experts in 2000-01 has indicated occurrence of more than 200 species of corals in Andaman islands alone. The total number of coral species if surveyed and identified properly may increase further. Coral reefs are among the most dynamic and productive ecosystems of the world. They prevent coastal erosion, act as primary producer and are important breeding and nursery ground for shell fish. They provide shelter to juvenile fish and larvae of many organisms. They also provide sustenance and employment to people living around.

India’s beautiful diversity in marine life is a huge boon to the country. It contributes to tourism, provides jobs, pushes exports of marine goods, thereby benefitting the economy in so many ways. It is thus, our righteous duty, to preserve and propel ways that enrich the marine ecosystem all around the globe. 

[1] http://www.upsbdb.org/pdf/Souvenir2012/ch-14.pdf

 [2] https://www.omicsonline.org/conference-proceedings/marine-science-oceanography-2018-posters-abstracts.digital/files/assets/basic-html/page-15.html