1. Approximately, 70% of the earth’s surface is covered by oceans. Besides oceans, there are rivers, lakes, etc., which are freshwater sources.
2. Biomes are found in water, too. Here, the plants and animals have adapted themselves to the existing climatic conditions.
3. The aquatic biomes consist of any part of the earth that is covered with water, including fresh water and saltwater.
4. The aquatic biome can be further divided into freshwater biomes, marine biomes, wetland biomes, coral reef biomes, estuaries, etc., based on the salt content of the water and the aquatic plants that live there.
In the marine biomes, there are three layers:
(i) Euphotic Layer: It is found till a depth of 200 m and sunlight can reach here. It houses many fishes, sea turtles, jellyfish, seals, corals, zooplankton, and mangroves.
(ii) Disphotic Layer: It is the middle layer. Here, some light penetrates to the bottom part. It is around 1000 m deep from the mean sea level. Except for a few phytoplankton that has sunk from the upper layer, plants are not found here. Squid, cuttlefish, wolfish, swordfish, eels, sea dragons, etc., are found. These creatures are adapted to darkness, cold water, and high pressure.
(iii) Aphotic Layer: It is the third and the deepest layer that ranges from 1000 m to 4000 m depth. No light penetrates here. There is no living plant life. Inhabitants of this cold dark environment include elusive giant squid, bioluminescent jellyfish, angler fish, hatchet fish, etc. Sperm whales enter this zone to hunt but return to the upper layers. Beyond this layer, lies the darkest and deepest zone extending up to the seafloor. Here, the animals are adapted to survive on detritus under even greater pressure.
