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Diel vertical migration

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Title: Diel vertical migration  
Author: World Heritage Encyclopedia
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Subject: Zooplankton, Marine larval ecology, Deep sea fish, Deep scattering layer, Abralia veranyi
Collection: Animal Migration, Aquatic Ecology, Biological Oceanography, Marine Biology, Planktology
Publisher: World Heritage Encyclopedia

Diel vertical migration

Diel vertical migration, also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as epipelagic zone at night and return to the mesopelagic zone of the oceans or to the hypolimnion zone of lakes during the day. The word diel comes from the Latin dies day, and means a 24-hour period. It is referred to as the greatest migration in the world in terms of biomass.[1]


  • Discovery 1
  • Types and stimuli of vertical migration 2
    • Endogenous factors 2.1
    • Exogenous factors 2.2
    • Types of vertical migration 2.3
  • Reasons for vertical migration 3
  • Importance with the biological pump 4
  • See also 5
  • References 6


During World War II the U.S. Navy was taking sonar readings of the ocean when they discovered the deep scattering layer (DSL). The DSL was caused by large groupings of organisms that scattered the sonar to create a false or second bottom. The false bottom was shallower during the night and deeper during the day; this was the first recording of diel vertical migration.

Once scientists started to do more research on what was causing the DSL, it was discovered that a large range of organisms were vertically migrating. Most types of plankton and some types of nekton have exhibited some type of vertical migration, although it is not always diel. These migrations may have substantial effects on mesopredators and apex predators by modulating the concentration and accessibility of their prey (i.e. impacts on the foraging behavior of pinnipeds[2]).

Types and stimuli of vertical migration

There are two different factors that are known to play a role in vertical migration, biological rhythms, etc. Exogenous factors are environmental factors acting on the organism such as light, gravity, oxygen, temperature, predator-prey interactions, etc.

Endogenous factors

Endogenous rhythm
An experiment was done at the [3]

Exogenous factors[4]

Organisms want to find an optimum light intensity (isolume). Whether it is no light or a large amount of light, an organism will travel to where it is most comfortable. Studies have shown that during a full moon organisms will not migrate up as far or during an eclipse they will start to migrate.
Sometimes thermoclines can act as a barrier that an organism will not cross.
in areas such as the Arctic melting ice causes a layer of freshwater which organisms cannot cross.
Predator kairomones
a predator might release a chemical cue which could cause its prey to vertically migrate away.[5]

Types of vertical migration

This is the most common form. Organisms migrate daily, usually up to shallow waters at night and deep waters during the day.
Organisms are found at different depths depending on what season it is.[6]
Organisms spend different stages of their life cycle at different depths.[7]

Reasons for vertical migration

There are many hypotheses as to why organisms would vertically migrate, and several may be valid at any given time.[8]

Predator avoidance
Organisms come up to shallow waters at night to feed while it’s dark out because their predators cannot see them as easily.
Metabolic advantages
By feeding in the warm surface waters at night and residing in the cooler deep waters during the day they can conserve energy. Alternatively, organisms feeding on the bottom in cold water during the day may migrate to surface waters at night in order to digest their meal at warmer temperatures.
Dispersal and transport
Organisms can use deep and shallow currents to find food patches or to maintain a geographical location.
Avoid UV damage
The sunlight can penetrate into the water column. If an organism, especially something small like a microbe, is too close to the surface the UV can damage them. So they would want to avoid getting too close to the surface, especially during daylight.

Importance with the biological pump

The euphotic zone and transference to the deeper ocean.[9] This is a major process in the ocean and without vertical migration it wouldn’t be nearly as efficient. The deep ocean gets most of its nutrients from the higher water column when they sink down in the form of marine snow. This is made up of dead or dying animals and microbes, fecal matter, sand and other inorganic material.

Organisms migrate up to feed at night so when they migrate back to depth during the day they defecate large sinking fecal pellets.[9] Whilst some larger fecal pellets can sink quite fast, the speed that organisms move back to depth is still faster. At night organisms are in the top 100 metres of the water column, but during the day they move down to between 800–1000 meters. If organisms were to defecate at the surface it would take the fecal pellets days to reach the depth that they reach in a matter of hours. Therefore by releasing fecal pellets at depth they have almost 1000 metres less to travel to get to the deep ocean. This is something known as active transport. The organisms are playing a more active role in moving organic matter down to depths. Because a large majority of the deep sea, especially marine microbes, depends on nutrients falling down, the quicker they can reach the ocean floor the better.

  1. ^ "Diel Vertical Migration (DVM)". Retrieved 5 April 2012. 
  2. ^ Horning, M., Trillmich, F. (1999). "Lunar cycles in diel prey migrations exert a stronger effect on the diving of juveniles than adult Galapagos fur seals".  
  3. ^ Enright, J.T.; W.M. Hammer (1967). "Vertical Diurnal Migration and Endogenous Rhythmicity". Science 157 (3791): 937–941.  
  4. ^ Richards, Shane; Hugh Possingham; John Noye (1996). "Diel vertical migration: modeling light-mediated mechanisms" (PDF). Journal of Plankton Research 18 (12): 2199–2222.  
  5. ^ von Elert, Eric; Georg Pohnert (2000). "Diel Predator specificity of kairomones in diel vertical migration of Daphnia: a chemical approach". OIKOS 88 (1): 119–128.  
  6. ^ Visser, Andre; Sigrun Jonasdottir (1999). "Lipids, buoyancy and the seasonal vertical migration of Calanus finmarchicus". Fisheries Oceanography 8: 100–106.  
  7. ^ Kobari, Toru; Tsutomu Ikeda (2001). "Octogenetic vertical migration and life cycle of Neocalanus plumchrus (Crustacea:Copepoda) in the Oyashio region, with notes on regional variations in body size" (PDF). Journal of Plankton Research 23 (3): 287–302.  
  8. ^ Kerfoot, WC (1985). "Adaptive value of vertical migration: Comments on the predation hypothesis and some alternatives". Contributions in Marine Science 27: 91–113. 
  9. ^ a b c Steinberg, Deborah; Sarah Goldthwait; Dennis Hansell (2002). "Zooplankton vertical migration and the active transport of dissolved organic and inorganic nitrogen in the Sargasso Sea". Deep-Sea Research I 49 (8): 1445–1461.  
  10. ^ Wiebe, P.H; L.P. Madin; L.R. Haury; G.R. Harbison; L.M. Philbin (1979). "Diel Vertical Migration by Salpa aspera and its potential for large-scale particulate organic matter transport to the deep-sea". Marine Biology 53 (3): 249–255.  


See also


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