A biome is a defined geographical area where plants and animals have adapted to live in the specific type of environment that area presents. The climate and the geography determine what type of biome can exist in a certain region. An abyssal zone biome is an area of a certain deep sea habitat type with a characteristic biodiversity for this type of habitat.
All bodies of water are divided into different zones. The abyssal zone is found in deep seas at depths of 4000 to 6000 m. No sunlight can reach down to the abyssal zone and it stays in perpetual darkness. The creatures that live in this zone has adapted to a life in total darkness and to withstand the tremendous pressure of such depths. The abyssal zone has a temperature of 2-3 C and the content of nutrients is low.
Hydrothermal vents are common in abyssal regions. They form along mid-ocean ridges where the tectonic plates are diverging. The vents are fissures that emit geothermally heated water up to temperatures of 400 C. The high pressure prevents the water from boiling. Some vents form chimney-like structures when minerals emitted from the vents come in contact with the cold near freezing cold sea water. Some vent chimneys can grow up to 30 cm in a day.
The vents emit hydrogen sulphide, heavy metals, poisonous gas and extremely hot water which make the environment hostile for most types of creatures. Surprisingly a certain kind of bacteria, chemosynthetic archaea, lives and thrives on and near these vents as they manage to convert the hydrogen sulphide into energy through chemosynthesis. To find thriving ecosystems in such a living environment was an amazing discovery as it was previously thought that all life depended on converting sunlight into energy through photosynthesis. The bacteria form the base of the food chain and become an important nutrient to other species in the abyssal zone. Tubeworms, eels, snails and shrimps are only a few species feeding on the bacteria. The areas around vents are therefore often very biologically productive in comparison to other parts of the deep sea. Over 300 new species have been recorded in vent areas.
The harsh environment of the abyssal zone is home to the most peculiar creatures. As food is scarce they have developed different ways to attract and catch prey. Some use bioluminescence to catch the attention lure victims to come close. Others have under-slung jaws to sift through sand for hiding prey.
The abyssal zone biome us the largest biome in the world as it covers about 60% of earth’s surface. It provides the harshest living conditions on earth but still life thrives – in a bizarre looking way.