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Underwater vision is the ability to see objects underwater, and this is significantly affected by several factors. Underwater, objects are less visible because of lower levels of natural illumination caused by rapid attenuation of light with distance passed through the water. They are also blurred by scattering of light between the object and ...
Open water is unrestricted water such as a sea, lake or flooded quarry, where the diver has unobstructed direct vertical access to the surface of the water in contact with the atmosphere. [6] Open-water diving implies that if a problem arises, the diver can directly ascend vertically to the atmosphere to breathe the ambient air. [7]
At sea level, the Rayleigh atmosphere has an extinction coefficient of approximately 13.2 × 10 −6 m −1 at a wavelength of 520 nm. This means that in the cleanest possible atmosphere, visibility is limited to about 296 km. Visibility perception depends on several physical and visual factors.
An underwater ecosystem can have high water clarity yet low water quality, and vice versa. Scientists have observed that many lakes are becoming less clear while also recovering from acid rain . This phenomenon has been seen in the northeastern United States and northern Europe.
The environment may affect gear configuration: for instance, freshwater is less dense than saltwater, so less added weight is needed to achieve diver neutral buoyancy in freshwater dives. [115] Water temperature, visibility and movement also affect the diver and the dive plan. [116]
Diving physics, or the physics of underwater diving, is the basic aspects of physics which describe the effects of the underwater environment on the underwater diver and their equipment, and the effects of blending, compressing, and storing breathing gas mixtures, and supplying them for use at ambient pressure. These effects are mostly ...
Water temperature, visibility and movement also affect the diver and the dive plan. [3] Diving in liquids other than water may present special problems due to density, viscosity and chemical compatibility of diving equipment, as well as possible environmental hazards to the diving team.
An underwater environment is a environment of, and immersed in, liquid water in a natural or artificial feature (called a body of water), such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer. Some characteristics of the underwater environment are universal, but many depend on the local situation.