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All You Need to Know About the Amazing Marine Biome

Marine Biome
With water covering 70% of the Earth's surface, the marine biome happens to be the largest biome in the world. Thanks to symbiotic existence in the deep waters, it is not only interesting but also diverse.
Rita Putatunda
Last Updated: Apr 17, 2018
"...Just look at the world around you
Right here on the ocean floor
Such wonderful things surround you
What more is you lookin' for?..."
- 'Under The Sea' Raven Symone
A biome is a specific geographic area notable for the species living there. A biome often encompasses a number of ecosystems. On the bases of the physical features of the planet, there exists two broad categories of biomes, namely the terrestrial biome and the aquatic biome, pertaining to land and water respectively.

Marine biome as one understands, pertains to the life in the large salt water bodies, that is, the oceans. With oceans covering two-thirds of the Earths surface, it is house to the largest biomes that exist on the planet.

Marine biomes can be further classified into three major types - ocean biomes, coral reefs and estuaries.
Life in the Ocean
oceanic divisions
The ocean is divided into the oceanic, neritic, intertidal zones with the oceanic zone pertaining to the deep open ocean, while the intertidal zones lie close to the coastline. These zones are created on the basis of the distance from the shore to the more deeper parts of the ocean.
Littoral Zone
It is known as the intertidal zone as it lies submerged during the high tides and is revealed during the low tides. In other words, it is the area closest to the coast which is easily accessible by humans. The region is characterized by frequent turbulence due to the tides and is susceptible to daily changes in temperature, moisture and salinity. This zone is further subdivided into four zones based on the amount of tidal action they get. The zones are the spray zone, the high intertidal zone, the mid intertidal zone and the low intertidal zone.

This zone is house to a variety of snails, anemones, crabs, urchins, mussels, molluscs and barnacles. Besides, one is sure to find types of seaweeds, lichen, kelp and mangroves lining the coast which support marine life along the coast.
Anemonefish In Underwater
Spotted Anemone Crab
Neritic Zone
This zone is essentially what one knows as the continental shelf. Being close to the seashore, this zone is characterized with stable temperature and salinity levels, making it a perfect area for marine life to thrive. It forms the base for the marine food pyramid, thanks to the presence of phytoplankton and zooplankton that are present in abundance in this area.

This area is popular among the fisher folk as being the most productive area of the ocean owing to the presence of fishing areas in these parts. Apart from different types of algae and bacteria, one is sure to find different varieties of fish including tuna, herring, mackerels, and invertebrates like lobsters. A common sight in this area are bottlenose dolphins and turtles.
Turtle In Blue Ocean
Oceanic Zone
Way beyond the continental slope, lies the open ocean that is home to most of the marine animals. A dip into the ocean is enough to tell us, that life in the ocean is diverse. For one, the ocean is not just wide but has depth as well. Which means, one is sure to find diverse ecosystems existing in different parts of the oceans. The blue water body as we know it to be, is divided into different vertical zones depending on the amount of sunlight penetrating through the surface of the water.
Epipelagic Zone
This top layer of the ocean is well-lit, thereby sustaining a majority of the marine life. It is also known as the euphotic zone or the 'sun-lit zone' as it receives enough sunlight to support the process of photosynthesis.

This zone contains both phytoplankton and zooplankton that support larger marine organisms. Sharks, dolphins, floating seaweeds, jellyfish, tuna and plankton are some of the marine life found here. On a closer look, around 90% of the ocean life is found in this zone.
Mesopelagic Zone
Lying immediately below the euphotic zone, this zone receives scarce amount of light. Owing to the soft glow of light that makes its presence felt in this zone, it is popularly called the 'twilight zone'. It is also called the disphotic zone and it extends to 1000 meters.

Marine animals like the swordfish, varieties of the squid, wolf eels and cuttlefish are found here. To adapt to their surroundings, many organisms are bioluminescent and are known to rise to the higher layers to feed.
Bathypelagic Zone
The midnight zone, or the aphotic zone lies below the disphotic zone and is characterized by extreme water pressure and cold temperatures. Owing to the extreme darkness prevailing here, it has been termed as the 'midnight zone'.

This zone receives absolutely no sunlight, which is why, no flora are found in this zone. Characterized by pitch darkness, the inhabitants of this zone are bioluminescent. They thrive on the detritus sinking from the zones above. The creatures dwelling here are unusual, unique, and often bizarre. They include the giant squid, dumbo octopus, varieties of the anglerfish and viperfish.
Abyssopelagic Zone
This zone is found between 4000 m and 6000 m below sea level. Owing to its extreme depth, this zone never receives sunlight and is home to the giant squid, deep-sea anglerfish, and tripod fish. The temperature in the abyssopelagic zone ranges between 2 °C to 3 °C (35 °F to 37 °F). This zone is followed by the hadal range or zone, which is marked by trenches.
The Action on the Reefs
Warm, shallow waters provide the best ambiance for a coral reef to exist. All the color and vibrancy that are an indispensable part of the coral reef, make it quite intriguing for biologists. The reefs are essentially structures formed from the skeletons of the coral polyps. These reefs provide shelter for many marine animals, thus forming a complex habitat in itself. They are also known to be the rainforests of the oceans.

Despite being poor in nutrients, the coral reefs are capable of supporting rich diversity of marine life thanks to the symbiotic relationship they have established with the microscopic algae. The zooxanthellae algae is what attracts both people and marine animals towards itself.

The animals found on the coral reef include sea fans, sharks, different varieties of fish apart from reptiles like turtles and sea snakes.
Clownfish In Its Host Anemone
Pink Anemonefish
Clarks Anemonefish In Orange Bulb Anemone
The Protected Estuaries
Popularly known as mudflats, or mangroves, these partially enclosed water bodies are an interesting ground for many marine animals to take shelter. It is characterized by brackish water, formed due to the mixing of the salty ocean water with the freshwater streams at the mouth of the rivers. Working as natural buffers between land and the open ocean, these estuaries are known to be nutrient houses. The mangroves and mudflats are known to filter out the nutrients and sediments from the freshwater thus becoming storehouses of the same.

High productive zones that they are, the estuaries are home to a huge number of organisms and are known to be fish nurseries. Apart from marine life, estuaries are known to support a wide variety of migratory birds that feed here.
Apart from adding aesthetic beauty to planet earth, the marine biome is an important aspect of our planet. Water, which is the source of all life is found in plenty here. It is from the oceans water, that we receive rainfall and thus gain fresh water supply to satiate our needs. Besides, the phytoplankton living in the oceans account for most of the photosynthesis occurring on earth. Obviously, the marine biome is a large contributor to the production of the essential oxygen which is why adequate care needs to be taken to ensure the conservation of this biome.