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Benthic zone

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Title: Benthic zone  
Author: World Heritage Encyclopedia
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Subject: Littoral zone, Demersal fish, Sea, Benthic lander, Aphotic zone
Collection: Aquatic Biomes, Aquatic Ecology, Fisheries Science, Oceanographical Terminology, Oceanography
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Benthic zone

The benthic zone is the ecological region at the lowest level of a benthic boundary layer, is an integral part of the benthic zone, as it greatly influences the biological activity which takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud.


  • Description 1
  • Organisms 2
  • Nutrient flux 3
  • Habitats 4
  • Ecological research 5
  • See also 6
  • References 7
  • External links 8


The benthic region of the ocean begins at the shore line (intertidal or eulittoral zone) and extends downward along the surface of the continental shelf out to sea.[2] The continental shelf is a gently sloping benthic region that extends away from the land mass. At the continental shelf edge, usually about 200 meters deep, the gradient greatly increases and is known as the continental slope. The continental slope drops down to the deep sea floor. The deep-sea floor is called the abyssal plain and is usually about 4,000 meters deep. The ocean floor is not all flat but has submarine ridges and deep ocean trenches known as the hadal zone.

For comparison, the pelagic zone is the descriptive term for the ecological region above the benthos, including the water-column up to the surface. Depending on the water-body, the benthic zone may include areas which are only a few inches below water, such as a stream or shallow pond; at the other end of the spectrum, benthos of the deep ocean includes the bottom levels of the oceanic abyssal zone.

For information on animals that live in the deeper areas of the oceans see aphotic zone. Generally, these include life forms that tolerate cool temperatures and low oxygen levels, but this depends on the depth of the water.


Benthos are the organisms which live in the benthic zone, and are different from those elsewhere in the atmosphere for each 10 meters of water depth).

Because light does not penetrate very deep into ocean-water, the energy source for the benthic ecosystem is often organic matter from higher up in the water column which drifts down to the depths. This chemosynthesis to produce biomass.

Benthic organisms can be divided into two categories based on whether they make their home on the ocean floor or an inch or two into the ocean floor. Those living on the surface of the ocean floor are known as epifauna.[4] Those who live burrowed into the ocean floor are known as infauna.[5] Extremophiles like the piezophile which can survive in high pressures may also live there.

Nutrient flux

Sources of food for benthic communities can derive from the water column above these habitats in the form of aggregations of

  • Data Archive for Seabed Species and Habitats from the UK Marine Data Archive Centre

External links

  1. ^ "What Are Benthos?". 2006-01-23. Retrieved 2013-11-24. 
  2. ^ a b c "Physico-chemical Parameters and Macrobenthic Invertebrates of the Intertidal Zone of Gusa, Cagayan de Oro City, Philippines". Retrieved 2015-11-01. 
  3. ^ Bright, Michael (2000). The private life of sharks : the truth behind the myth. Mechanicsburg, PA: Stackpole Books.  
  4. ^ "Epifaunal - Definition and More from the Free Merriam-Webster Dictionary". 2012-08-31. Retrieved 2013-11-24. 
  5. ^ "Infauna - Definition and More from the Free Merriam-Webster Dictionary". 2012-08-31. Retrieved 2013-11-24. 
  6. ^ Alldredge, Alice; Silver, Mary W. (1988). "Characteristics, dynamics and significance of marine snow". Progress in Oceanography 20: 41–82.  
  7. ^ Shanks, Alan; Trent, Jonathan D. (1980). "Marine snow: sinking rates and potential role in vertical flux". Deep-Sea Research 27A (2): 137–143.  
  8. ^ "Foraminifera". Retrieved 7 December 2014. 
  9. ^ "foraminifera". Retrieved 7 December 2014. 
  10. ^ Royal Belgian Institute of Natural Sciences, news item March 2005
  11. ^ Minshall, Wayne; Shafii, Bahman; Price, William J.; Holderman, Charlie; Anders, Paul J.; Lester, Gary; Barrett, Pat. "Effects of nutrient replacement on benthic macroinvertebrates in an ultraoligotrophic reach of the Kootenai River, 2003–2010". Freshwater Science.  
  12. ^ Rolls, Robert; Leigh, Catherine; Sheldon, Fran (2012). "Mechanistic effects of low-flow hydrology on riverine ecosystems: ecological principles and consequences of alteration". Freshwater Science 31 (4): 1163–1186.  
  13. ^ Bennion, Helen; Kelly, Martyn G.; Juggins, Steve; Yallop, Marian L.; Burgess, Amy; Jamieson, Jane; Krokowski, Jan (2014). "Assessment of Ecological Status in UK lakes using benthic diatoms". Freshwater Science 33 (2): 639–654.  
  14. ^ Lowe, Michael; Peterson, Mark S. (2014). "Effects of Coastal Urbanization on Salt-Marsh Faunal Assemblages in the Northern Gulf of Mexico". Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science 6: 89–107.  
  15. ^ Wellnitz, Todd; Rader, Russell B. (2003). "Mechanisms influencing community composition and succession in mountain stream periphyton: interactions between scouring history, grazing, and irradiance". Journal of the North American Benthological Society 22 (4): 528–541.  
  16. ^ Althouse, Bryan; Higgins, Scott; Vander Zanden, Jake M. (2014). "Benthic and Planktonic primary production along a nutrient gradient in Green Bay, Lake Michigan, USA". Freshwater Science 33 (2): 487–498.  


See also

Ecologists are attempting to understand the relationship between heterogeneity and maintaining biodiversity in aquatic ecosystems. Benthic algae has been used as an inherently good subject for studying short term changes and community responses to heterogeneous conditions in streams. Understanding the potential mechanisms involving benthic periphyton and the effects on heterogeneity within a stream may provide a better understanding of the structure and function of stream ecosystems.[15] Benthic gross primary production (GPP) may be important in maintaining biodiversity hotspots in littoral zones in large lake ecosystems. However, the relative contributions of benthic habitats within specific ecosystems are poorly explored and more research is needed.[16]

Because the benthic system regulates energy in aquatic ecosystems, studies have been made of the mechanisms of the benthic zone in order to better understand the ecosystem. Benthic diatoms have been used by the European Union’s Water Framework Directive (WFD) to establish ecological quality ratios that determined the ecological status of lakes in the UK.[13] Beginning research is being made on benthic assemblages to see if they can be used as indicators of healthy aquatic ecosystems. Benthic assemblages in urbanized coastal regions are not functionally equivalent to benthic assemblages in untouched regions.[14]

Benthic substrates to food webs, and caused a decrease in benthic macroinvertebrate biomass, which lead to the disappearance of food sources into the substrate.[12]

Ecological research

It is not easy to map or observe these organisms and their habitats, and most observation has been done through remote controlled submarines.

The lower zones are in deep, pressurized areas of the ocean. Because of the high pressures and seclusion neither tidal changes nor human impacts have had much of an effect on these areas, and the habitats have not changed much over the years. Many benthic organisms have retained their historic evolutionary characteristics. Some organisms are significantly larger than their relatives living in shallower zones, largely because of higher oxygen concentration in deep water.[10]

In oceanic environments, benthic habitats can be further zoned by depth. From the shallowest to the deepest are: the epipelagic (less than 200 meters), the mesopelagic (200–1,000 metres), the bathyal (1,000–4,000 meters), the abyssal (4,000–6,000 meters) and the deepest, the hadal (below 6,000 meters).


[9][8], colonize quite rapidly on detritus matter while forming a symbiotic relationship with each other.foraminifera and dinoflagellates This amount will vary on the depth of the benthos, and the degree of benthic-pelagic coupling. The benthos in a shallow region will have more available food than the benthos in the deep sea. Because of their reliance on it, microbes may become spatially dependent on detritus in the benthic zone. The microbes found in the benthic zone, specifically [7] per day.2 The amount of material sinking to the ocean floor can average 307,000 aggregates per m[6]

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