Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Diel vertical migration
Summary
Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The word "diel" (IPA: ˈdaɪ.əl, ˈdiː.əl) comes from diēs, and means a 24-hour period. The migration occurs when organisms move up to the uppermost layer of the sea at night and return to the bottom of the daylight zone of the oceans or to the dense, bottom layer of lakes during the day. It is important to the functioning of deep-sea food webs and the biologically driven sequestration of carbon.
In terms of biomass, it is the largest synchronous migration in the world. It is not restricted to any one taxon as examples are known from crustaceans (copepods), molluscs (squid), and ray-finned fishes (trout).
The phenomenon may be advantageous for a number of reasons, most typically to access food and avoid predators.
It is triggered by various stimuli, the most prominent being response to changes in light intensity, though evidence suggests that biological clocks are an underlying stimulus as well. While this mass migration is generally nocturnal, with the animals ascending from the depths at nightfall and descending at sunrise, the timing can be altered in response to the different cues and stimuli that trigger it. Some unusual events impact vertical migration: DVM can be absent during the midnight sun in Arctic regions and vertical migration can occur suddenly during a solar eclipse. The phenomenon also demonstrates cloud-driven variations.
The common swift is an exception among birds in that it ascends and descends into high altitudes at dusk and dawn, similar to the vertical migration of aquatic lifeforms.
The phenomenon was first documented by French naturalist Georges Cuvier in 1817. He noted that daphnia, a type of plankton, appeared and disappeared according to a diurnal pattern.
During World War II the U.S. Navy was taking sonar readings of the ocean when they discovered the deep scattering layer (DSL).
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.