Information about Photic Zone
The photic zone or euphotic zone (Greek 'well lit') is the depth of the water whether in a lake or an ocean, that is exposed to sufficient sunlight for photosynthesis to occur. The depth of the euphotic zone can be greatly affected by seasonal turbidity.
It extends from the atmosphere-ocean interface downwards to a depth where light intensity falls to 1% of that at the surface (also called euphotic depth), so its thickness depends on the extent of light attenuation in the water column. Typical euphotic depths vary from only a few centimetres in highly turbid eutrophic lakes, to around 200 metres in the open ocean.
Since the euphotic zone is the only zone of water where primary productivity occurs, an exception being the productivity connected with abyssal hydrothermal vents along mid-oceanic ridges, the depth of the photic zone is generally proportional to the level of primary productivity that occurs in that area of the ocean.
The transparency of the water, which determines the depth of the Euphotic zone, is simply measured with a Secchi disk.
It extends from the atmosphere-ocean interface downwards to a depth where light intensity falls to 1% of that at the surface (also called euphotic depth), so its thickness depends on the extent of light attenuation in the water column. Typical euphotic depths vary from only a few centimetres in highly turbid eutrophic lakes, to around 200 metres in the open ocean.
Since the euphotic zone is the only zone of water where primary productivity occurs, an exception being the productivity connected with abyssal hydrothermal vents along mid-oceanic ridges, the depth of the photic zone is generally proportional to the level of primary productivity that occurs in that area of the ocean.
The transparency of the water, which determines the depth of the Euphotic zone, is simply measured with a Secchi disk.
See also
Greek}}}
Writing system: Greek alphabet
Official status
Official language of: Greece
Cyprus
European Union
recognised as minority language in parts of:
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Italy
Turkey
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Writing system: Greek alphabet
Official status
Official language of: Greece
Cyprus
European Union
recognised as minority language in parts of:
European Union
Italy
Turkey
Regulated by:
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Earth's oceans
(World Ocean)
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(World Ocean)
- Arctic Ocean
- Atlantic Ocean
- Indian Ocean
- Pacific Ocean
- Southern Ocean
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Sunlight, in the broad sense, is the total spectrum of the electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon.
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Turbidity is a cloudiness or haziness of a fluid, or of air, caused by individual particles (suspended solids) that are generally invisible to the naked eye, similar to smoke in air.
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Attenuation is the reduction in amplitude and intensity of a signal. Signals may be attenuated exponentially by transmission through a medium, in which case attenuation is usually reported in dB with respect to distance traveled through the medium.
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Turbidity is a cloudiness or haziness of a fluid, or of air, caused by individual particles (suspended solids) that are generally invisible to the naked eye, similar to smoke in air.
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A eutrophic lake is a lake with high primary productivity, the result of high nutrient content. These lakes are subject to excessive algal blooms, resulting in murky water and poor water quality.
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A hydrothermal vent, also called a "black smoker", is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, tectonic plates that are moving apart, ocean basins, and hotspots.
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mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent
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Primary production is the production of organic compounds from atmospheric or aquatic carbon dioxide, principally through the process of photosynthesis, with chemosynthesis being much less important. All life on earth is directly or indirectly reliant on primary production.
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In optics, transparency is the material property of allowing light to pass through. In mineralogy, another term for this property is diaphaneity. The opposite property is opacity. Transparent materials are clear: they can be seen through.
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Secchi disk is a device used to measure water transparency in open waters of lakes, bays, and the ocean. The pattern shown in the image is drawn or painted onto a card or acrylic, mounted on a pole or line, and lowered slowly down in the water.
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The pelagic zone is the part of the open sea or ocean that is not near the coast. In contrast, the neritic zone comprises the water that is near to (and is significantly affected by) the coast or the continental shelf.
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The aphotic zone is the portion of a lake or ocean that is not exposed to sunlight. No light other than bioluminescence is found in this zone. Most food comes from dead organisms sinking to the bottom of the lake or ocean from other zones.
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