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Spreading rate is the rate at which an ocean basin widens due to seafloor spreading. (The rate at which new oceanic lithosphere is added to each tectonic plate on either side of a mid-ocean ridge is the spreading half-rate and is equal to half of the spreading rate). Spreading rates determine if the ridge is fast, intermediate, or slow.
For example, for visible light, the refractive index of glass is typically around 1.5, meaning that light in glass travels at c / 1.5 ≈ 200 000 km/s (124 000 mi/s); the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 90 km/s (56 mi/s) slower than c.
The speed of light in vacuum is defined to be exactly 299 792 458 m/s (approximately 186,282 miles per second). The fixed value of the speed of light in SI units results from the fact that the metre is now defined in terms of the speed of light. All forms of electromagnetic radiation move at exactly this same speed in vacuum.
The decreased light intensity, replicates the typical lighting experienced at night time that stimulate the planktonic organisms to migrate. During an eclipse, some copepod species distribution is concentrated near the surface, for example Calanus finmarchicus displays a classic diurnal migration pattern but on a much shorter time scale during ...
Mid-ocean ridges exhibit active volcanism and seismicity. [3] The oceanic crust is in a constant state of 'renewal' at the mid-ocean ridges by the processes of seafloor spreading and plate tectonics. New magma steadily emerges onto the ocean floor and intrudes into the existing ocean crust at and near rifts along the ridge axes. The rocks ...
Ocean currents are important in the study of marine debris. [15] [16] Plankton are dispersed by ocean currents. Upwellings and cold ocean water currents flowing from polar and sub-polar regions bring in nutrients that support plankton growth, which are crucial prey items for several key species in marine ecosystems. [17]
Depending on how it is defined, the aphotic zone of the ocean begins between depths of about 200 m (660 ft) to 800 m (2,600 ft) and extends to the ocean floor. [ 1 ] [ 2 ] [ 3 ] The majority of the ocean is aphotic, with the average depth of the sea being 4,267 m (13,999 ft) deep; the deepest part of the sea, the Challenger Deep in the Mariana ...
Large eyes would allow the detection and use of any light available, no matter how small. [3] Commonly, animals in the abyssal zone are bioluminescent, producing blue light, because light in the blue wavelength range is attenuated over greater travel distances than other wavelengths. [13]