how does the depth of the deep scattering layer vary over the course of a day?

It was noticed that this layer moved vertically according to the time of day. At night it would rise to the surface while, during the hours of daylight, it would descend to a depth that rarely exceeded 2,000 fathoms.

Full Answer

What is the deep scattering layer of the ocean?

Deep scattering layer. The deep scattering layer, sometimes referred to as the sound scattering layer, is a name given to a layer in the ocean consisting of a variety of marine animals. It was discovered through the use of sonar, as ships found a layer that scattered the sound and was thus sometimes mistaken for the seabed.

What is another name for the scattering layer?

Alternative Title: scattering layer. Deep-scattering layer, horizontal zone of living organisms, usually schools of fish, occurring below the surface in many ocean areas, so called because the layer scatters or reflects sound waves, causing echoes in depth sounders.

Do sound scatterers migrate at Bathy/abyssopelagic depths?

A few studies have observed diel migrations of sound scatterers between the depths of 500 and 1000 m or from bathypelagic depths (> 1000 m) upward. Nevertheless, there is yet little evidence for migrations of animals living at bathy/abyssopelagic depths.

Why does the ocean get shallower at night?

It turned out to be due to millions of marine organisms, most particularly small mesopelagic fish, with swimbladders that reflected the sonar. These organisms migrate up into shallower water at dusk to feed on plankton. The layer is deeper when the moon is out, and can become shallower when clouds pass over the moon.

How does the depth of the deep scattering layer vary over the course of a day Why does it do this which organisms comprise the DSL?

Why does it do this? Which organisms comprise the DSL? The deep scattering layer is a sonar-reflecting surface that undergoes a daily vertical migration in response to light intensity between the depths of 100 to 200 meters (330 to 660 feet) about midnight, and 900 meters (2950 feet) at noon.

What is the deep scattering layer and why does it migrate vertically during the day?

It was discovered through the use of sonar, as ships found a layer that scattered the sound and was thus sometimes mistaken for the seabed. For this reason it is sometimes called the false bottom or phantom bottom. It can be seen to rise and fall each day in keeping with diel vertical migration.

What is the depth range for the scattering layer?

about 200–1,000 mIntroduction. Deep scattering layers (DSL) are a near universal feature throughout the worlds oceanic regions at depths of about 200–1,000 m (Irigoien et al., 2014).

Why does the deep scattering layer migrate?

Animals in the scattering layer reside in deeper waters during the day, and travel up to surface areas to feed at night to avoid detection by visual predators.

Why does vertical migration occur?

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.

Why do deep-sea benthic organisms have a major advantage over deep-sea pelagic ones?

The major advantage that deep-sea benthic animals have over pelagic ones is that their food: Falls to the bottom and stays in one place, thus being available for a longer time.

What is the depth of the open ocean?

As far as we know, the ocean is 36,200 feet (11,000 m or almost 7 miles) deep at its deepest point. On average, the ocean is about 12,100 feet (3,688 m) deep.

What do deep water animals depend on the surface for?

In addition to food, deep-water animals depend on the surface for: oxygen. The mesopelagic zone extends from about 200 m to about: 1,000 m.

Is there a false bottom of the Mariana Trench?

The false bottom, however, was a global phenomenon. Sonar operators across every ocean reported similar findings — indications of something substantial, miles wide in every direction, where no seafloor should be. More curious still, it moved. During daylight hours, the phantom bottom readings remained steady.

What do you call deep ocean?

Bathypelagic. The bathypelagic is between 3,300 and 13,100 feet (1,000 and 4,000 m) beneath the ocean surface. It is an area void of light (called aphotic) and at 39 degrees Fahrenheit (4 degrees Celsius), it is very cold.

How deep is the ocean in phantom?

One reason these deep sea creatures are hard to find is that they lurk 21,900 feet below the surface. This depth of the ocean is called the midnight, or bathypelagic zone, where sunlight does not penetrate, reports Brian Kahn for Gizmodo.

What methods do scientists use to explore the deep sea floor?

Answer. Technologies used to explore outer space and the ocean include submersibles, remotely operated vehicles (ROVs), satellites, rovers, diving/scuba gear, buoys, mega corers, water column samplers, and sonar for mapping.

What is the layer that scatters sound waves?

Alternative Title: scattering layer. Deep-scattering layer, horizontal zone of living organisms, usually schools of fish, occurring below the surface in many ocean areas, so called because the layer scatters or reflects sound waves, causing echoes in depth sounders.

What is oceanography?

oceanography. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Deep-scattering layer, horizontal zone of living organisms, usually schools of fish, occurring below the surface in many ocean ...

What are topographic features? What are some examples?

For example, seamounts are often sites of seabird aggregation, likely related to the fact that they are also sites of increased density and heightened migratory activity for organisms comprising the deep scattering layer. A second example are topographic features in relatively shallow water, including depressions in the tops of reefs and ridges across the slope of marine escarpments, which may physically trap euphausiids as they attempt to migrate downward in the morning. A third example is the downstream, eddy effect of islands that occur in strong current systems.

What are the primary zooplanktivores in the open ocean?

The DSL micronekton, which includes fishes (e.g., myctophids, gonostomids), squid, and crustaceans (especially euphausiids and sergestid shrimps) are likely the primary zooplanktivores in the open ocean.

Why do zooplankton dive at night?

Zooplanktonexploit the phytoplanktonat night but dive to allow thephytoplankton to photosynthesize and to recover during the day, so that they canbe exploited again the following night.

What is the most common pattern of marine zooplankton?

This is the most common pattern displayed by marine zooplankton. It ischaracterized by a single daily ascent, usually beginning near sunset, and a singledescent from the upper layers which occurs near sunrise. Many midwaterzooplankton and fish rise from the mesopelagic to the epipelagic zone at duskanddescend to their previous level at sunrise. These vertical migrations can bedetected through the movement of deep scattering layersrevealed by sonar.

What is seasonal vertical migration?

seasonal vertical migration(SVM) is a migration pattern through the watercolumn that is triggered by a change in the seasons. In some species, SVMmay be associated with breeding cycles and changing depth preferences ofdifferent stages in the life cycle.