Aphotic zone

Aphotic zone

The aphotic zone (aphotic from Greek prefix polytonic|ἀ- + polytonic|φῶς "without light") is the portion of a lake or ocean where there is little or no sunlight.

It is formally defined as the depths beyond which less than 1% of sunlight penetrates. Consequently, bioluminescence is essentially the only light found in this zone. Most food comes from dead organisms sinking to the bottom of the lake or ocean from overlying waters.

The depth of the aphotic zone can be greatly affected by such things as turbidity and the season of the year. The aphotic zone underlies the photic zone, which is that portion of a lake or ocean directly affected by sunlight.

The Ocean

The aphotic zone of the ocean is 0.9 - 4.6 km (3,000 - 15,000 feet) deepFact|date=March 2007 and the temperatures range from 0 - 6°C (32 - 43°F)Fact|date=March 2007. Unusual and unique creatures dwell in this expanse of pitch black water, such as the gulper eel, the giant squid, the anglerfish, and the vampire squid.

The aphotic zone is divided into two parts- the bathyal zone and the abyssal zone. The bathyal zone extends from 200 metersFact|date=June 2008 to 2000 meters. The abyssal zone extends from 2000 meters to the bottom. Creatures in this area must be able to live in complete darkness.

ee also

* Abyssal zone
* Benthic zone
* Pelagic zone
* Photic zone


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  • aphotic zone — afotinė zona statusas T sritis ekologija ir aplinkotyra apibrėžtis Neapšviestas vandens sluoksnis, kuriame negalima efektyvi fotosintezė. atitikmenys: angl. aphotic zone vok. aphotische Tiefenstufe, f rus. афотическая зона, f; лишенная света зона …   Ekologijos terminų aiškinamasis žodynas

  • aphotic zone — That zone of ocean water that lies below 800 meters and which receives little or no light …   Dictionary of invertebrate zoology

  • aphotic zone — noun that part of the deep body of an ocean or lake that receives insufficient sunlight for photosynthesis to be possible …   Wiktionary

  • aphotic — (adj.) untouched by sunlight, lightless (in reference to deep sea regions), 1903, Modern Latin, from Gk. a not, without (see A (Cf. a ) (3)) + phos (gen. photos) light, related to phainein to show, to bring to light (see PHANTASM (Cf. phantasm))… …   Etymology dictionary

  • aphotic — [ā fōt′ik] adj. [ A 2 + PHOTIC] without light; specif., pertaining to that part (aphotic zone) of the ocean below a depth of c. 100 m ( c. 328 ft) which does not receive sufficient sunlight for photosynthesis: see EUPHOTIC …   English World dictionary

  • aphotic — adjective Date: circa 1900 being the deep zone of an ocean or lake receiving too little light to permit photosynthesis …   New Collegiate Dictionary

  • Benthic zone — The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub surface layers. Organisms living in this zone are called benthos. They generally live in… …   Wikipedia

  • Oceanic zone — Marine habitats The oceanic zone is the deep open ocean water that lies off the continental slopes Littoral zone Intertidal zone …   Wikipedia

  • Profundal zone — The profundal zone is a deep zone of a body of water, such as an ocean or a lake, located below the range of effective light penetration. This is typically below the thermocline, the vertical zone in the water through which temperature drops… …   Wikipedia

  • photic zone — Biol. the upper layer of a body of water delineated by the depth to which enough sunlight can penetrate to permit photosynthesis. [1970 75] * * * ▪ oceanography       surface layer of the ocean that receives sunlight. The uppermost 80 m (260… …   Universalium

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