Abyssal zone

Deep oceanic zone

For other uses, see Abyssal zone (disambiguation).

The abyssal zone is a layer of the pelagic zone of the ocean. "Abyss" derives from the Greek word _______, meaning "bottomless." At depths of 3,000 to 6,000 meters (9,800 to 19,700 ft), this zone remains in perpetual darkness and is characterized by extreme pressure, low temperatures, and high salinity.

Characteristics

The abyssal zone is defined by its depth and the absence of sunlight. Temperatures in this zone are near freezing, typically ranging from 2 to 3 °C (36 to 37 °F). The pressure is immense, reaching up to 600 times that of the surface atmosphere. Despite these harsh conditions, the abyssal zone is home to a variety of life forms.

Pressure and Temperature

The pressure in the abyssal zone increases by approximately one atmosphere for every 10 meters of depth. This high pressure affects the physiology of organisms living in this environment, requiring specialized adaptations. The temperature remains consistently cold, which influences the metabolic rates of abyssal organisms.

Light and Visibility

The abyssal zone is devoid of sunlight, making it a region of complete darkness. Bioluminescence is a common adaptation among abyssal organisms, allowing them to produce light for communication, predation, and camouflage.

Flora and Fauna

Life in the abyssal zone is adapted to the extreme conditions of high pressure, low temperature, and darkness. Organisms include a variety of invertebrates, fish, and microorganisms.

Invertebrates

Invertebrates such as sea cucumbers, polychaete worms, and crustaceans are common in the abyssal zone. These organisms often have slow metabolisms and unique adaptations to survive in the high-pressure environment.

Fish

Abyssal fish, such as the anglerfish and gulper eel, have adaptations like large mouths and expandable stomachs to capture scarce prey. Many of these fish exhibit bioluminescence.

Microorganisms

Microbial life in the abyssal zone includes bacteria and archaea that can survive in extreme conditions. Some of these microorganisms are chemosynthetic, deriving energy from chemical reactions rather than sunlight.

Hydrothermal Vents

Hydrothermal vents are found in the abyssal zone and are characterized by the emission of mineral-rich water heated by the Earth's mantle. These vents support unique ecosystems that rely on chemosynthesis rather than photosynthesis.

Human Exploration

Exploration of the abyssal zone is challenging due to its depth and harsh conditions. Advances in submersible technology have allowed scientists to study this remote environment, leading to discoveries of new species and ecosystems.

Related pages

• Pelagic zone
• Benthic zone
• Midnight zone
• Deep-sea exploration

Gallery

• 
  Diagram of oceanic zones, including the abyssal zone.
• 
  A shrimp near a hydrothermal vent in the abyssal zone.

Abyssal zone

• 
  Diagram of the pelagic zones, including the abyssal zone.
• 
  Close-up of a Beebe shrimp near a hydrothermal vent chimney.