Benthic zone - wikipedia Benthic zone Marine habitats Photomicrograph of typical benthic animals, ( from top to bottom ) including amphipods, a polychaete worm, a snail, and a chironomous midge larva Littoral zone Intertidal zone Estuaries Kelp forests Coral reefs Ocean banks Continental shelf Neritic zone Straits Pelagic zone Oceanic zone Seamounts Hydrothermal vents Cold seeps Demersal zone 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, e.g. the benthic invertebrate community, including crustaceans and polychaetes. The organisms generally live in close relationship with the substrate bottom and many are permanently attached to the bottom. The superficial layer of the soil lining the given body of water, the benthic boundary layer, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Contents 1 Description 2 Organisms 3 Nutrient flux 4 Habitats 5 Ecological research 6 See also 7 References 8 External links Description 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. 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 that 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. Organisms Main article : Benthos Benthos are the organisms that live in the benthic zone, and are different from those elsewhere in the water column. Many have adapted to live on the substrate ( bottom ). In their habitats they can be considered as dominant creatures, but they are often a source of prey for Carcharhinidae such as the lemon shark. Many organisms adapted to deep - water pressure can not survive in the upper parts of the water column. The pressure difference can be very significant ( approximately one 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 that drifts down to the depths. This dead and decaying matter sustains the benthic food chain ; most organisms in the benthic zone are scavengers or detritivores. Some microorganisms use 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. Those who live burrowed into the ocean floor are known as infauna. Extremophiles, including piezophiles, which thrive 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 detritus, inorganic matter, and living organisms. These aggregations are commonly referred to as marine snow, and are important for the deposition of organic matter, and bacterial communities. The amount of material sinking to the ocean floor can average 307,000 aggregates per m per day. 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 dinoflagellates and foraminifera, colonize quite rapidly on detritus matter while forming a symbiotic relationship with each other. Habitats Modern seafloor mapping technologies have revealed linkages between seafloor geomorphology and benthic habitats, in which suites of benthic communities are associated with specific geomorphic settings. Examples include cold - water coral communities associated with seamounts and submarine canyons, kelp forests associated with inner shelf rocky reefs and rockfish associated with rocky escarpments on continental slopes. In oceanic environments, benthic habitats can also be 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 ). The lower zones are in deep, pressurized areas of the ocean. Human impacts have occurred at all ocean depths, but are most significant on shallow continental shelf and slope habitats. 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. It is not easy to map or observe these organisms and their habitats, and most modern observations are made using remotely operated underwater vehicles ( ROVs ), and rarely submarines. Ecological research Benthic macroinvertebrates have many important ecological functions, such as regulating the flow of materials and energy in river ecosystems through their food web linkages. Because of this correlation between flow of energy and nutrients, benthic macroinvertebrates have the ability to influence food resources on fish and other organisms in aquatic ecosystems. For example, the addition of a moderate amount of nutrients to a river over the course of several years resulted in increases in invertebrate richness, abundance, and biomass. These in turn resulted in increased food resources for native species of fish with insignificant alteration of the macroinvertebrate community structure and trophic pathways. The presence of macroinvertebrates such as Amphipoda also affect the dominance of certain types of algae in Benthic ecosystems as well. In addition, because benthic zones are influenced by the flow of dead organic material, there have been studies conducted on the relationship between stream and river water flows and the resulting effects on the benthic zone. Low flow events show a restriction in nutrient transport from benthic substrates to food webs, and caused a decrease in benthic macroinvertebrate biomass, which lead to the disappearance of food sources into the substrate. 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. 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. 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. 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. See also Armor ( hydrology ) Benthic fish Benthopelagic fish Bottom trawling Deep sea Intertidal zone Lake stratification Littoral zone Neritic zone Photic zone Profundal zone Sediment Profile Imagery Stream bed Tide pool References Jump up ^ `` What Are Benthos ? ''. Baybenthos.versar.com. 2006 - 01 - 23. Retrieved 2013 - 11 - 24. ^ Jump up to : Angelo Mark P. Walag ; Mae Oljae P. Canencia ( 2016 ). `` Physico - chemical Parameters and Macrobenthic Invertebrates of the Intertidal Zone of Gusa, Cagayan de Oro City, Philippines ''. Advances in Environmental Sciences - International Journal of the Bioflux Society. 8 ( 1 ) : 71 -- 82. Retrieved 2015 - 12 - 08. ( registration required ) Jump up ^ Bright, Michael ( 2000 ). The private life of sharks : the truth behind the myth. Mechanicsburg, Pennsylvania : Stackpole Books. ISBN 0 - 8117 - 2875 - 7. Jump up ^ `` Epifaunal - Definition and More from the Free Merriam - Webster Dictionary ''. Merriam-webster.com. 2012 - 08 - 31. Retrieved 2013 - 11 - 24. Jump up ^ `` Infauna - Definition and More from the Free Merriam - Webster Dictionary ''. Merriam-webster.com. 2012 - 08 - 31. Retrieved 2013 - 11 - 24. Jump up ^ Alldredge, Alice ; Silver, Mary W. ( 1988 ). `` Characteristics, dynamics and significance of marine snow ''. Progress in Oceanography. 20 : 41 -- 82. doi : 10.1016 / 0079 - 6611 ( 88 ) 90053 - 5. Jump up ^ Shanks, Alan ; Trent, Jonathan D. ( 1980 ). `` Marine snow : sinking rates and potential role in vertical flux ''. Deep - Sea Research. 27A ( 2 ) : 137 -- 143. doi : 10.1016 / 0198 - 0149 ( 80 ) 90092 - 8. Jump up ^ `` Foraminifera ''. Retrieved 7 December 2014. Jump up ^ `` foraminifera ''. Retrieved 7 December 2014. Jump up ^ Harris, P.T. ; Baker, E.K. 2012. `` GeoHab Atlas of seafloor geomorphic features and benthic habitats -- synthesis and lessons learned '', in : Harris, P.T. ; Baker, E.K. ( eds. ), Seafloor Geomorphology as Benthic Habitat : GeoHab Atlas of seafloor geomorphic features and benthic habitats. Elsevier, Amsterdam, pp. 871 - 890. Jump up ^ Harris, P.T. ; Baker, E.K. ; 2012. Seafloor Geomorphology as Benthic Habitat : GeoHab Atlas of seafloor geomorphic features and benthic habitats. Elsevier, Amsterdam, p. 947. Jump up ^ Harris, P.T., 2012. `` Anthropogenic threats to benthic habitats '', in : Harris, P.T. ; Baker, E.K. ( eds. ), Seafloor Geomorphology as Benthic Habitat : GeoHab Atlas of seafloor geomorphic features and benthic habitats. Elsevier, Amsterdam, pp. 39 - 60. Jump up ^ Royal Belgian Institute of Natural Sciences, news item March 2005 Archived September 28, 2011, at the Wayback Machine. Jump up ^ 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. JSTOR 10.1086 / 677900. doi : 10.1086 / 677900. Jump up ^ Duffy, J. Emmett ; Hay, Mark E. ( 2000 - 05 - 01 ). `` Strong impacts of grazing amphipods on the organization of a benthic community ''. Ecological Monographs. 70 ( 2 ) : 237 -- 263. ISSN 0012 - 9615. doi : 10.1890 / 0012 - 9615 ( 2000 ) 070 ( 0237 : SIOGAO ) 2.0.CO ; 2. Jump up ^ 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. JSTOR 10.1899 / 12 - 002.1. doi : 10.1899 / 12 - 002.1. Jump up ^ 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. JSTOR 10.1086 / 675447. doi : 10.1086 / 675447. Jump up ^ 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. doi : 10.1080 / 19425120.2014. 893467. Jump up ^ 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. JSTOR 1468350. doi : 10.2307 / 1468350. Jump up ^ 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. JSTOR 10.1086 / 676314. doi : 10.1086 / 676314. External links Wikimedia Commons has media related to Benthic zones. Data Archive for Seabed Species and Habitats from the UK Marine Data Archive Centre Physical oceanography Waves Airy wave theory Ballantine scale Benjamin -- Feir instability Boussinesq approximation Breaking wave Clapotis Cnoidal wave Cross sea Dispersion Edge wave Equatorial waves Fetch Gravity wave Green 's law Infragravity wave Internal wave Iribarren number Kelvin wave Kinematic wave Longshore drift Luke 's variational principle Mild - slope equation Radiation stress Rogue wave Rossby wave Rossby - gravity waves Sea state Seiche Significant wave height Soliton Stokes boundary layer Stokes drift Stokes wave Swell Trochoidal wave Tsunami megatsunami Undertow Ursell number Wave action Wave base Wave height Wave power Wave radar Wave setup Wave shoaling Wave turbulence Wave -- current interaction Waves and shallow water one - dimensional Saint - Venant equations shallow water equations Wind wave model Circulation Atmospheric circulation Baroclinity Boundary current Coriolis force Coriolis -- Stokes force Craik -- Leibovich vortex force Downwelling Eddy Ekman layer Ekman spiral Ekman transport El Niño -- Southern Oscillation General circulation model Geostrophic current Global Ocean Data Analysis Project Gulf Stream Halothermal circulation Humboldt Current Hydrothermal circulation Langmuir circulation Longshore drift Loop Current Modular Ocean Model Ocean dynamics Ocean gyre Princeton Ocean Model Rip current Subsurface currents Sverdrup balance Thermohaline circulation shutdown Upwelling Whirlpool World Ocean Circulation Experiment Tides Amphidromic point Earth tide Head of tide Internal tide Lunitidal interval Perigean spring tide Rip tide Rule of twelfths Slack water Tidal bore Tidal force Tidal power Tidal race Tidal range Tidal resonance Tide gauge Tideline Landforms Abyssal fan Abyssal plain Atoll Bathymetric chart Coastal geography Cold seep Continental margin Continental rise Continental shelf Contourite Guyot Hydrography Oceanic basin Oceanic plateau Oceanic trench Passive margin Seabed Seamount Submarine canyon Submarine volcano Plate tectonics Convergent boundary Divergent boundary Fracture zone Hydrothermal vent Marine geology Mid-ocean ridge Mohorovičić discontinuity Vine -- Matthews -- Morley hypothesis Oceanic crust Outer trench swell Ridge push Seafloor spreading Slab pull Slab suction Slab window Subduction Transform fault Volcanic arc Ocean zones Benthic Deep ocean water Deep sea Littoral Mesopelagic Oceanic Pelagic Photic Surf Swash Sea level Deep - ocean Assessment and Reporting of Tsunamis Future sea level Global Sea Level Observing System North West Shelf Operational Oceanographic System Sea - level curve Sea level rise World Geodetic System Acoustics Deep scattering layer Hydroacoustics Ocean acoustic tomography Sofar bomb SOFAR channel Underwater acoustics Satellites Jason - 1 Jason - 2 ( Ocean Surface Topography Mission ) Jason - 3 Related Argo Benthic lander Color of water DSV Alvin Marginal sea Marine energy Marine pollution Mooring National Oceanographic Data Center Ocean Ocean exploration Ocean observations Ocean reanalysis Ocean surface topography Ocean thermal energy conversion Oceanography Pelagic sediment Sea surface microlayer Sea surface temperature Seawater Science On a Sphere Thermocline Underwater glider Water column World Ocean Atlas Commons Retrieved from `` https://en.wikipedia.org/w/index.php?title=Benthic_zone&oldid=801933725 '' Categories : Aquatic biomes Aquatic ecology Fisheries science Oceanographical terminology Hidden categories : Pages with login required references or sources Webarchive template wayback links All articles with failed verification Articles with failed verification from April 2016 Talk Contents About Wikipedia Беларуская Беларуская ( тарашкевіца ) ‎ Català Dansk Deutsch Eesti Español Esperanto فارسی Gaeilge Hrvatski Bahasa Indonesia മലയാളം Nederlands Norsk Oʻzbekcha / ўзбекча Polski Português Русский Türkçe Українська 中文 Edit links This page was last edited on 22 September 2017, at 21 : 29. 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Question: where do benthic organisms live in aquatic ecosystems
Answer: at the lowest level of a body of water