Underwater vision

The ability to see objects underwater

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Scuba diver with bifocal lenses fitted to a mask

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 the viewer, also resulting in lower contrast. These effects vary with wavelength of the light, and color and turbidity of the water. The vertebrate eye is usually either optimised for underwater vision or air vision, as is the case in the human eye. The visual acuity of the air-optimised eye is severely adversely affected by the difference in refractive index between air and water when immersed in direct contact. Provision of an airspace between the cornea and the water can compensate, but has the side effect of scale and distance distortion. The diver learns to compensate for these distortions. Artificial illumination is effective to improve illumination at short range.[1]

Stereoscopic acuity, the ability to judge relative distances of different objects, is considerably reduced underwater, and this is affected by the field of vision. A narrow field of vision caused by a small viewport in a helmet results in greatly reduced stereoacuity, and associated loss of hand-eye coordination.[1] At very short range in clear water distance is underestimated, in accordance with magnification due to refraction through the flat lens of the mask, but at greater distances - greater than arm's reach, the distance tends to be overestimated to a degree influenced by turbidity. Both relative and absolute depth perception are reduced underwater. Loss of contrast results in overestimation, and magnification effects account for underestimation at short range.[1] Divers can to a large extent adapt to these effects over time and with practice.[1]

Light rays bend when they travel from one medium to another; the amount of bending is determined by the refractive indices of the two media. If one medium has a particular curved shape, it functions as a lens. The cornea, humours, and crystalline lens of the eye together form a lens that focuses images on the retina. The eye of most land animals is adapted for viewing in air. Water, however, has approximately the same refractive index as the cornea (both about 1.33), effectively eliminating the cornea's focusing properties. When immersed in water, instead of focusing images on the retina, they are focused behind the retina, resulting in an extremely blurred image from hypermetropia.[2] This is largely avoided by having an air space between the water and the cornea, trapped inside the mask or helmet.

Water attenuates light due to absorption[2] and as light passes through water colour is selectively absorbed by the water. Color absorption is also affected by turbidity of the water and dissolved material. Water preferentially absorbs red light, and to a lesser extent, yellow, green and violet light, so the color that is least absorbed by water is blue light.[3] Particulates and dissolved materials may absorb different frequencies, and this will affect the color at depth, with results such as the typically green color in many coastal waters, and the dark red-brown color of many freshwater rivers and lakes due to dissolved organic matter.[1]

Visibility is a term which generally predicts the ability of some human, animal, or instrument to optically detect an object in the given environment, and may be expressed as a measure of the distance at which an object or light can be discerned.[4] Factors affecting visibility include illumination, length of the light path, particles which cause scattering, dissolved pigments which absorb specific colours, and salinity and temperature gradients which affect refractive index.[5] Visibility can be measured in any arbitrary direction, and for various colour targets, but horizontal visibility of a black target reduces the variables and meets the requirements for a straight-forward and robust parameter for underwater visibility.[4] Instruments are available for field estimates of visibility from the surface, which can inform the dive team on probable complications.

## Illumination

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See also: Snell's window

Illumination of underwater environments is limited by the characteristics of the water. Light absorption by water is variable and depends on the temperature of the water and concentration of ions (salinity). Accurate values for the absorption coefficient and the temperature and salinity coefficients are available for specific ranges and values of wavelength from 400nm to 14000nm.There are three dominant molrcular vibration modes but the absorption spectrum in liquid water is a continuum. Light scattering is also variable depending on temperature and salinity.[6]

### Natural Illumination

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Natural illumination underwater comes primarily from sunlight during the day and moonlight at night in the uppermost layer. In deeper regions, where solar light does not penetrate, bioluminescence—light produced by living organisms—provides the primary source of natural illumination. In marine environments, light availability defines five major zones: the epipelagic, mesopelagic, bathypelagic, abyssopelagic, and hadalpelagic zones, in order of least to greatest depth.[7]

* Epipelagic zone(also known as sunlit zone): Extending to a depth of about 200 meters (656 feet), the epipelagic is where most natural light exists. The epipelagic zone is lit up by rays of sunlight that can penetrate roughly 200 meters of depth. [7][8]
* Mesopelagic zone(also known as twilight zone): Extending from a depth of about 200 meters (656 feet) to 1,000 meters (3,280 feet), is just beyond the reach of most sunlight. The mesopelagic zone receives faint sunlight but is home to bioluminescence—light producing organisms.[7][8]
* Bathypelagic zone (also known as midnight zone): Extending from a depth of about 1,000-4,000 meters (3,280-13,120 feet), the bathypelagic zone is well beyond the range of sunlight. It is characterized by almost complete darkness broken only by light from bioluminescent organisms.[7][8]
* Abyssopelagic zone (also known as abyssal zone): Extending from a depth of about 4,000-6,000 meters (3,280-19,690 feet), the abyssopelagic zone is pitch-black but inhabited by bioluminescent organisms. The ocean floor usually lies in this zone.[7][8]
* Hadalpelagic zone (also known as hadal zone): At a depth of 6,000 meters (19,690 feet) and greater, the hadalpelagic zone is the deepest zone of the ocean, and exists only in trenches such as the Mariana Trench. Similar to the abyssopelagic zone, it is pitch-black and receives light only from bioluminescent organisms.[8][7]

### Artificial illumination

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See also: Artificial lighting

Artificial illumination refers to illumination by man-made sources such as flashlights and lanterns. Underwater, artificial illumination is generally rare, but its sources are often lights equipped to divers and submersibles.

### Light absorption and scattering

[edit]

* backscatter has a greater effect when from artificial illumination as the light source is more likely to be close to the viewer than for natural light.

## Evolution of the eye

[edit]

Main article: Evolution of the eye

Major stages in the evolution of the eye in vertebrates

Eyes originated, developed and diversified by natural selection as organs of photosensitivity and vision in living organisms. The eye exemplifies convergent evolution of an organ found in many animal forms. Simple light detection is found in bacteria, single-celled organisms, plants and animals. Complex, image-forming eyes have evolved independently several times.[9]

### Types of eye

[edit]

Further information: Eye § Types

There are several types of eye, comprising simple eyes, with one concave photoreceptive surface, and compound eyes which include a group of individual lenses laid out over a convex surface. Each of these major types has several lesser variations, with about 10 significant types recognised.

All of these originated in aquatic organisms, and therefore have, at some stages of their evolution, been adapted primarily for underwater vision. Some lineages took to terrestrial life, and their eyes evolved further in that environment, and of those, a few returned to an amphibious or aquatic lifestyle, with further adaptation in some cases.

## Photosensitivity

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## Focus

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See also: Accommodation (vertebrate eye) and Focus (optics)

Water has a significantly different refractive index to air, and this affects the focusing of the eye. Most animals' eyes are adapted to either underwater or air vision, and do not focus properly when in the other environment.[citation needed]

## Variations by taxa

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Invertebrates have a large variety of eye structures. Most, possibly all, originated in an aquatic environment, but some have later adapted to a terrestrial environment, and later re-adapted to an aquatic environment.[citation needed] Vertebrates all evolved from a common marine vertebrate ancestor, which already had well developed underwater vision and a specific eye structure, which has been conserved, or in some cases atrophied in animals living in the lightless cave environment.[citation needed]

### Arthropods

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Main article: Arthropod eye

Most arthropods have at least one of two types of eye: lateral compound eyes, and smaller median ocelli, which are simple eyes.[10] When both are present, the two eye types are used in concert because each has its own advantage.[11] Ocelli can detect lower light levels,[a][12] and have a faster response time, while compound eyes are better at detecting edges and are capable of forming images.[11]

This section needs expansion with: Specific to underwater vision. You can help by adding to it. (March 2025)

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### Molluscs

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Main article: Mollusc eye

See also: Cephalopod eye

The molluscs have the widest variety of eye morphologies of any phylum,[13] and a large degree of variation in their function. Cephalopods such as octopus, squid, and cuttlefish have paired eyes on their heads as complex as those of vertebrates,[13] while scallops have large numbers of simple eyes along the edges of the shell opening,[14] and chitons have a dispersed network of tiny eyes over the surface of their shells which may act together as a compound eye. Many gastropods have stalked eyes which can be retracted in the presence of danger.[13]

There are between seven and eleven distinct eye types in molluscs,[15] of all levels of complexity, from the pit eyes of many gastropods, to the pinhole eyes of the Nautilus, to the lensed eyes of the other cephalopods. Compound eyes are present in some bivalves, and reflective 'mirrors' have been innovated by other lineages such as scallops.[13] The eyes of molluscs also span a large range in size, from 20 μm (0.0008 in) to 27 cm (11 in) across.[13]

### Fish

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Main article: Vision in fish

Fish eyes are similar to the eyes of terrestrial vertebrates like birds and mammals, but the crystalline lenses of fishes' eyes are extremely convex, almost spherical, and their refractive indices are the highest of all the animals.[16] Birds and mammals normally adjust focus by changing the shape of their lens, but fish normally adjust focus by moving the lens closer to or further from the retina. Due to a refractive index gradient within the lens[17] the spherical lenses of fish are able to form sharp images free from spherical aberration.[18]Fish retinas generally have both rod cells and cone cells (for scotopic and photopic vision), and most species have colour vision. Some fish can see ultraviolet and some are sensitive to polarised light.

Among jawless fishes, the lamprey has well-developed eyes,[19] while the hagfish has only primitive eyespots.[20] The ancestors of modern hagfish, thought to be the protovertebrate,[21] were evidently pushed to very deep, dark waters, where they were less vulnerable to sighted predators, and where it is advantageous to have a convex eye-spot, which gathers more light than a flat or concave one. Fish vision shows evolutionary adaptation to their visual environment, for example deep sea fish have eyes suited to the dark environment.

### Amphibians

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Amphibians evolved from lobe finned fish, and generally spend the first part of their life cycle in an aquatic environment and the later part in a terrestrial environment.

This section needs expansion. You can help by adding to it. (March 2025)

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### Aquatic vertebrates of terrestrial descent

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Reptiles, birds and mammals

#### Pinnipeds

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See also: Pinniped § Senses

Monochromatic?

#### Cetaceans

[edit]

See also: Cetacea § Vision

Monochromatic?

This section needs expansion. You can help by adding to it. (March 2025)

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### Humans

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See also: Diving mask

Views through a flat mask, above and below water

The human eye is not adapted for underwater vision, but by wearing a flat diving mask, humans can see clearly underwater.[2][22][23] The mask's flat window separates the eyes from the surrounding water by a layer of air. Light rays entering from water into the flat parallel window change their direction minimally within the window material itself.[2] But when these rays exit the window into the air space between the flat window and the eye, the refraction is quite noticeable. The view paths refract (bend) in a manner similar to viewing fish kept in an aquarium. Linear polarizing filters decrease visibility underwater by limiting ambient light and dimming artificial light sources.[1]

While wearing a flat scuba mask or goggles, objects underwater will appear 33% bigger (34% bigger in salt water) or 25% closer than they actually are.[2] Also pincushion distortion and lateral chromatic aberration are noticeable. Double-dome masks restore natural sized underwater vision and field of view, with certain limitations.[2][24]

#### Optical correction

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Divers can wear contact lenses under the diving mask or helmet. The risk of loss depends on the security of the mask or helmet, and is very low with a helmet. Framed lenses are available for wear in some helmets and full-face masks, but they can be difficult to defog if there is no fresh, dry, gas flow over them. The frame may be mounted to the helmet or mask, or worn on the head in the usual way, but they cannot be adjusted during a dive if they move out of position.

Glasses worn outside the mask will have different refraction out of the water to underwater, because of the different refractive indices of air and water in contact with the lens surfaces.

Diving masks can be fitted with lenses for divers needing optical correction to improve vision. Corrective lenses are ground flat on one side and optically cemented to the inside face of the mask lens. This provides the same amount of correction above and below the surface of the water as the curved surface of the lens is in contact with air in both cases. Bifocal lenses are also available for this application. Some masks are made with removable lenses, and a range of standard corrective lenses are available which can be fitted. Plastic self-adhesive lenses that can be applied to the inside of the mask may fall off if the mask is flooded for a significant period. Contact lenses may be worn under a mask or helmet, but there is some risk of losing them if the mask floods.[24][25]

#### Physiological variations

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A very near-sighted person can see more or less normally underwater [citation needed]. Scuba divers with interest in underwater photography may notice presbyopic changes while diving before they recognize the symptoms in their normal routines due to the near focus in low light conditions.[26]

The Moken people of South-East Asia are able to focus underwater to pick up tiny shellfish and other food items.[27] Gislén et al. have compared Moken and untrained European children and found that the underwater visual acuity of the Moken was twice that of their untrained European counterparts.[28] European children after 1 month of training also showed the same level of underwater visual acuity.[29] This is due to the contraction of the pupil, instead of the usual dilation (mydriasis) that is undergone when a normal, untrained eye, accustomed to viewing in air, is submerged.[30]

## Color vision

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Comparison of penetration of light of different wavelengths in the open ocean and coastal waters

Water attenuates light due to absorption[2] which varies as a function of frequency. In other words, as light passes through a greater distance of water color is selectively absorbed by the water. Color absorption is also affected by turbidity of the water and dissolved material.

Water preferentially absorbs red light, and to a lesser extent, yellow, green and violet light, so the color that is least absorbed by water is blue light.[3] Particulates and dissolved materials may absorb different frequencies, and this will affect the color at depth, with results such as the typically green color in many coastal waters, and the dark red-brown color of many freshwater rivers and lakes due to dissolved organic matter.[1]

Fluorescent paints absorb higher frequency light to which the human eye is relatively insensitive and emit lower frequencies, which are more easily detected. The emitted light and the reflected light combine and may be considerably more visible than the original light. The most visible frequencies are also those most rapidly attenuated in water, so the effect is for greatly increased colour contrast over a short range, until the longer wavelengths are attenuated by the water.[1]

Table of Light Absorption in pure water[citation needed] Color  | Average wavelength  | Approximate depth of total absorption

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Ultraviolet  | 300 nm  | 25 m
Violet  | 400 nm  | 100 m
Blue  | 475 nm  | 275 m
Green  | 525 nm  | 110 m
Yellow  | 575 nm  | 50 m
Orange  | 600 nm  | 20 m
Red  | 685 nm  | 5 m
Infrared  | 800 nm  | 3 m

The best colors to use for visibility in water was shown by Luria et al. and quoted from Adolfson and Berghage below:[2][22]

> A. For murky, turbid water of low visibility (rivers, harbors, etc.)

>     1\. With natural illumination:

>     a. Fluorescent yellow, orange, and red.
>     b. Regular yellow, orange, and white.
>     2\. With incandescent illumination:

>     a. Fluorescent and regular yellow, orange, red and white.
>     3\. With a mercury light source:

>     a. Fluorescent yellow-green and yellow-orange.
>     b. Regular yellow and white.

> B. For moderately turbid water (sounds, bays, coastal water).

>     1\. With natural illumination or incandescent light source:

>     a. Any fluorescent in the yellows, oranges, and reds.
>     b. Regular yellow, orange, and white.
>     2\. With a mercury light source:

>     a. Fluorescent yellow-green and yellow-orange.
>     b. Regular yellow and white.

> C. For clear water (southern water,[clarification needed] deep water offshore, etc.).

>     1\. With any type of illumination fluorescent paints are superior.

>     a. With long viewing distances, fluorescent green and yellow-green.
>     b. With short viewing distances, fluorescent orange is excellent.
>     2\. With natural illumination:

>     a. Fluorescent paints.
>     b. Regular yellow, orange, and white.
>     3\. With incandescent light source:

>     a. Fluorescent paints.
>     b. Regular yellow, orange, and white.
>     4\. With a mercury light source:

>     a. Fluorescent paints.
>     b. Regular yellow, white.

> The most difficult colors at the limits of visibility with a water background are dark colors such as gray or black.

## Visibility

[edit]

Visibility is a term which generally predicts the ability of some human or instrument to detect an object in the given environment, and may be expressed as a measure of the distance at which an object or light can be discerned.[4] The theoretical black body visibility of pure water based on the values for the optical properties of water for light of 550 nm has been estimated at 74 m.[31] For the case of a relatively large object, sufficiently illuminated by daylight, the horizontal visibility of the object is a function of the photopic beam attenuation coefficient (spectral sensitivity of the eye). This function has been reported as 4.6 divided by the photopic beam attenuation coefficient.[4]

Factors affecting visibility include: particles in the water (turbidity), salinity gradients (haloclines), temperature gradients (thermoclines) and dissolved organic matter.[5]

Reduction of contrast with distance in a horizontal plane at a specific wavelength has been found to depend directly on the beam attenuation coefficient for that wavelength. The inherent contrast of a black target is -1, so the visibility of a black target in the horizontal direction depends on a single parameter, which is not the case for any other colour or direction, making horizontal visibility of a black target the simplest case, and for this reason it has been proposed as a standard for underwater visibility, as it can be measured with reasonably simple instrumentation.[32]

The photopic beam attenuation coefficient, on which diver visibility depends, is the attenuation of natural light as perceived by the human eye, but in practice it is simpler and more usual to measure the attenuation coefficient for one or more wavelength bands. It has been shown that the function 4.8 divided by the photopic beam attenuation coefficient, as derived by Davies-Colley, gives a value for visibility with an average error of less than 10% for a large range of typical coastal and inland water conditions and viewing conditions, and the beam attenuation coefficients for a single wavelength band at about 530 nm peak is a suitable proxy for the full visible spectrum for many practical purposes with some small adjustments.[32]

### Measurement of visibility

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The standard measurement for underwater visibility is the distance at which a Secchi disc can be seen. The range of underwater vision is usually limited by turbidity. In very clear water visibility may extend as far as about 80m,[33] and a record Secchi depth of 79 m has been reported from a coastal polynya of the Eastern Weddell Sea, Antarctica.[33] In other sea waters, Secchi depths in the 50 to 70 m range have occasionally been recorded, including a 1985 record of 53 m in the Eastern and up to 62 m in the tropical Pacific Ocean. This level of visibility is seldom found in surface freshwater.[33] Crater Lake, Oregon, is often cited for clarity, but the maximum recorded Secchi depth using a 2 m disc is 44 m.[33] The lakes of the McMurdo Dry Valleys of Antarctica and Silfra in Iceland have also been reported as exceptionally clear.[citation needed]

Visibility can be measured in an arbitrary direction, and of various colour targets, but horizontal visibility of a black target reduces the variables and meets the requirements for a straight-forward and robust parameter for underwater visibility, which can be used to make operational decisions for mine hunters and explosive ordnance disposal teams.[4]

An instrument for measuring underwater visibility basically measures light transmission through the water between the target and the observer, to calculate the loss, and is called a transmissometer. By measuring the amount of light which is transmitted from a light source of known strength and wavelength distribution, through a known distance of water to a calibrated light meter, the clarity of water can be objectively quantified.[34] A wavelength of 532 nm (green) aligns well with the peak of the human visual perception spectrum, but other wavelengths may be used.[4] Transmissometers are more sensitive at low particulate concentration and are better suited for measuring relatively clear water.[35]

### Measurement of turbidity

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Nephelometers are used for measuring suspended particles in turbid waters where they have a more linear response than transmissometers. Turbidity, or cloudiness, of water is a relative measure. It is an apparent optical property which varies depending on the properties of the suspended particles, illumination, and instrument characteristics. Turbidity is measured in nephelometer units referenced to a turbidity standard or in Formazin Turbidity Units.[35]

Nephelometers measure the light scattered by suspended particles and respond mainly to the first-order effects of particle size and concentration. Depending on manufacturer, nephelometers measure scattered light in the range between about 90° to 165° off the axis of the beam, and usually use infra-red light with a wavelength of around 660 nm because this wavelength is rapidly absorbed by water, so there is very little contamination of the source due to ambient daylight except near to the surface.[35]

### Low visibility

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Low visibility refers to a diving environment where the diving medium is turbid and objects cannot be seen clearly at short range even with artificial illumination. The term is not usually used to refer to a simple lack of illumination when the medium is clear. Zero visibility is used to describe conditions when the diver can effectively see nothing outside the mask of helmet, and a light must be put against the viewport to see if it is switched on, and it is not possible for a person with normal vision to read normal instruments. (some mask-integrated head-up displays may be legible)

Low visibility is defined by NOAA for operational purposes as: "When visual contact with the dive buddy can no longer be maintained."[36]

DAN-Southern Africa suggest that limited visibility is when a "buddy cannot be discerned at a distance greater than 3 metres."[37]

## See also

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* Diving mask – Watertight air-filled face cover with view-ports for improving underwater vision
* Night vision – Ability to see in low light conditions
* Snell's law – Formula for refraction angles
* Underwater computer vision – Subfield of computer vision
* Underwater photography – Genre of photography

## Notes

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1. ^ Ocelli are about 5000 times more sensitive than apposition compound eyes. They can, for instance, respond to the position of the full moon.

## References

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1. ^ a b c d e f g h Luria, S. M.; Kinney, J. A. (December 1974). "Linear polarizing filters and underwater vision". Undersea Biomedical Research. 1 (4): 371–8\. PMID 4469103.
2. ^ a b c d e f g h Adolfson, J.; Berghage, T. (1974). Perception and Performance Under Water. John Wiley & Sons. ISBN 0-471-00900-8.
3. ^ a b Hegde, M. (30 September 2009). "The Blue, the Bluer, and the Bluest Ocean". NASA Goddard Earth Sciences Data and Information Services. Archived from the original on 12 July 2009. Retrieved 27 May 2011.
4. ^ a b c d e f "Water Visibility Research". www.seabird.com. Sea-bird Scientific. Retrieved 24 October 2021.
5. ^ a b Gibb, Natalie. "Factors That Affect Visibility Underwater When Diving". Scuba diving terminology. about.com. Archived from the original on 13 January 2017. Retrieved 26 November 2016.
6. ^ Röttgers, Rüdiger; McKee, David; Utschig, Christian (2014). "Temperature and salinity correction coefficients for light absorption by water in the visible to infrared spectral region". Optics Express. 22 (21): 25093–25108\. Bibcode:2014OExpr..2225093R. doi:10.1364/OE.22.025093. PMID 25401542.
7. ^ a b c d e f "Layers of the Ocean | National Oceanic and Atmospheric Administration". www.noaa.gov. Retrieved 2025-05-27.
8. ^ a b c d e "Hadal Zone - Woods Hole Oceanographic Institution". https://www.whoi.edu/. Retrieved 2025-05-27. `{{cite web}}`: External link in ``|website=`` (help)
9. ^ "An important cue for understanding eye evolution is the distinction between different types of photoreceptor cells. Salvini-Plawen and Mayr ( 1977 ) noted a remarkable diversity of photoreceptor cell morphology across the animal kingdom, and suggested that photoreceptors evolved independently numerous times." – Land, M.F. and Nilsson, D.-E., Animal Eyes(2-nd ed.), Oxford University Press, Oxford (2012), p. 7.
10. ^ Mayer, G. (2006). "Structure and development of onychophoran eyes: What is the ancestral visual organ in arthropods?". Arthropod Structure & Development. 35 (4): 231–245\. Bibcode:2006ArtSD..35..231M. doi:10.1016/j.asd.2006.06.003. PMID 18089073.
11. ^ a b Taylor, Charles P. (1981). "Contribution of compound eyes and ocelli to steering of locusts in flight. I. Behavioural analysis". J. Exp. Biol. 93: 1–18\. doi:10.1242/jeb.93.1.1.
12. ^ Wilson, M. (1978). "The functional organisation of locust ocelli". Journal of Comparative Physiology. 124 (4): 297–316\. doi:10.1007/bf00661380. S2CID 572458.
13. ^ a b c d e Serb, J.M.; Eernisse, D.J. (2008). "Charting Evolution's Trajectory: Using Molluscan Eye Diversity to Understand Parallel and Convergent Evolution". Evolution: Education and Outreach. 1 (4): 439–447\. doi:10.1007/s12052-008-0084-1.
14. ^ Land, M F; Fernald, R D (March 1992). "The Evolution of Eyes". Annual Review of Neuroscience. 15 (1): 1–29\. doi:10.1146/annurev.ne.15.030192.000245. PMID 1575438.
15. ^ "Camera eyes in gastropod molluscs". mapoflife.org.
16. ^ Wood, R. W. (1 August 1906). "XXIII. Fish-eye views, and vision under water". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. 12 (68): 159–162\. doi:10.1080/14786440609463529. ISSN 1941-5982.
17. ^ Wehner, R (2005). "Sensory physiology: brainless eyes" (PDF). Nature. 435 (7039): 157–159\. Bibcode:2005Natur.435..157W. doi:10.1038/435157a. PMID 15889076. S2CID 4408533.
18. ^ Land, M. F.; Nilsson, D. (2012). Animal Eyes. Oxford University Press. ISBN 9780199581146.
19. ^ Meyer-Rochow, V. Benno; Stewart, Duncan (1996). "Review of larval and postlarval eye ultrastructure in the lamprey (cyclostomata) with special emphasis on Geotria australis (gray)". Microscopy Research and Technique. 35 (6): 431–444\. doi:10.1002/(SICI)1097-0029(19961215)35:6<431::AID-JEMT3>3.0.CO;2-L. PMID 9016447. S2CID 22940203.
20. ^ Lamb, Trevor D.; Collin, Shaun P.; Pugh, Edward N. (2007). "Evolution of the vertebrate eye: opsins, photoreceptors, retina and eye cup". Nature Reviews Neuroscience. 8 (12): 960–976\. doi:10.1038/nrn2283. ISSN 1471-003X. PMC 3143066. PMID 18026166. See also Lamb et al.'s The origin of the Vertebrate Eye, 2008.
21. ^ Trevor D. Lamb; Shaun P. Collin; Edward N. Pugh Jr (2007). "Evolution of the vertebrate eye: opsins, photoreceptors, retina and eye cup". Nature Reviews Neuroscience. 8 (12): 960–976\. doi:10.1038/nrn2283. PMC 3143066. PMID 18026166.
22. ^ a b Luria, SM; Kinney, J. A. (March 1970). "Underwater vision". Science. 167 (3924): 1454–61\. Bibcode:1970Sci...167.1454L. doi:10.1126/science.167.3924.1454. PMID 5415277.
23. ^ Weltman, G.; Christianson, R. A.; Egstrom, G. H. (October 1965). "Visual fields of the scuba diver". Human Factors. 7 (5): 423–30\. doi:10.1177/001872086500700502. PMID 5882204. S2CID 45543055.
24. ^ a b Sawatzky, David (1 November 2015). "Corrective Dive Masks". Columns, Diving Medicine. Diver magazine. Retrieved 10 December 2016.
25. ^ Lonne, Torben (16 September 2015). "Diving With Contact Lenses". Articles. DIVE.in. Retrieved 10 December 2016.
26. ^ Bennett, Q. M. (June 2008). "New thoughts on the correction of presbyopia for divers". Diving and Hyperbaric Medicine. 38 (2): 163–4\. PMID 22692711.
27. ^ "Moken Sea Gypsies: Seeing Underwater". Archived from the original on August 29, 2008. Retrieved 2007-02-11.`{{cite web}}`: CS1 maint: bot: original URL status unknown (link)
28. ^ Gislén A, Dacke M, Kröger RH, Abrahamsson M, Nilsson DE, Warrant EJ (May 2003). "Superior underwater vision in a human population of sea gypsies". Curr. Biol. 13 (10): 833–6\. Bibcode:2003CBio...13..833G. doi:10.1016/S0960-9822(03)00290-2. PMID 12747831. S2CID 18731746.
29. ^ Gislén A, Warrant EJ, Dacke M, Kröger RH (October 2006). "Visual training improves underwater vision in children". Vision Res. 46 (20): 3443–50\. doi:10.1016/j.visres.2006.05.004. PMID 16806388.
30. ^ "How Mokens see clearly underwater, Building Your Brain, Inside the Human Body - BBC One". BBC. 13 May 2011. Retrieved 4 May 2018.
31. ^ Smith; Baker (1995). Davies-Colley, R.J.; Smith, D.G. (eds.). "Optically pure waters in Waikoropupu ('Pupu') Springs, Nelson, New Zealand". New Zealand Journal of Marine and Freshwater Research. 29 (2). The Royal Society of New Zealand: 251–256\. Bibcode:1995NZJMF..29..251D. doi:10.1080/00288330.1995.9516658. 0028-8330/95/2902-0251
32. ^ a b Zaneveld, J. Ronald V.; Pegau, W. Scott (2003). "Robust underwater visibility parameter". Optics Express. 11 (23). Optica Publishing Group: 2997–3009\. Bibcode:2003OExpr..11.2997Z. doi:10.1364/OE.11.002997. PMID 19471421.
33. ^ a b c d Davies-Colley, R. J.; Smith, D. G. (1995). "Optically pure waters in Waikoropupu ('Pupu') Springs, Nelson, New Zealand" (PDF). New Zealand Journal of Marine and Freshwater Research. 29 (2). The Royal Society of New Zealand: 251–256\. Bibcode:1995NZJMF..29..251D. doi:10.1080/00288330.1995.9516658. Retrieved 19 October 2013.0028-8330/95/2902-0251
34. ^ Rossier, Robert N. (3 November 1995). "What is visibility? Illuminating facts about an unclear situation\". dtmag.com. Dive Training Magazine. Retrieved 14 October 2021.
35. ^ a b c Thomson, Richard E.; Emery, William J. (2014). "Chapter 1 - Data Acquisition and Recording". In Thomson, Richard E.; Emery, Richard E. (eds.). Data Analysis Methods in Physical Oceanography (Third ed.). Elsevier. pp. 1–186\. doi:10.1016/B978-0-12-387782-6.00001-6. ISBN 9780123877826.
36. ^ Staff (9 July 2014). "Diving in low visibility" (PDF). Policy 0308. NOAA Office of Marine and Aviation Operations. p. 2. Retrieved 26 November 2016.
37. ^ Staff. "Lost Diver Procedure Guidelines" (PDF). Dive Safety Partners. Retrieved 4 January 2017.

## Further reading

[edit]

* Chou, B; Legerton, JA; Schwiegerling, J. "Improving Underwater Vision: Contact lenses and other options can help patients safely maximize their vision underwater". Contact Lens Spectrum (June 2007). Archived from the original on August 14, 2009. Retrieved 2009-06-27.

* v
* t
* e

Underwater diving

* Diving activities
* Diving modes
* Atmospheric pressure diving
* Freediving
* Saturation diving
* Scuba diving
* Snorkeling
* Surface oriented diving
* Surface-supplied diving
* Unmanned diving

Diving equipment

* Cleaning and disinfection of personal diving equipment
* Human factors in diving equipment design
* List of diving equipment manufacturers

| Basic equipment|

* Diving mask
* Snorkel
* Swimfin

|

Breathing gas|

* Bailout gas
* Bottom gas
* Breathing air
* Decompression gas
* Emergency gas supply
* Heliox
* Hydreliox
* Hydrox
* Nitrox
* Oxygen
* Travel gas
* Trimix

Buoyancy and
trim equipment|

* Avelo diving system
* Buoyancy compensator
* Power inflator
* Dump valve
* Variable buoyancy pressure vessel
* Diving weighting system
* Ankle weights
* Integrated weights
* Trim weights
* Weight belt

Decompression
equipment|

* Decompression buoy
* Decompression chamber
* Decompression cylinder
* Decompression trapeze
* Dive computer
* Diving bell
* Diving shot
* Diving stage
* Jersey upline
* Jonline

Diving suit|

* Atmospheric diving suit
* JIM suit
* Newtsuit
* Dry suit
* Sladen suit
* Standard diving suit
* Rash vest
* Wetsuit
* Dive skins
* Hot-water suit

Helmets
and masks|

* Anti-fog
* Diving helmet
* Free-flow helmet
* Lightweight demand helmet
* Orinasal mask
* Reclaim helmet
* Shallow water helmet
* Standard diving helmet
* Diving mask
* Band mask
* Full-face mask
* Half mask

Instrumentation|

* Bottom timer
* Depth gauge
* Dive computer
* Dive timer
* Diving watch
* Helium release valve
* Electro-galvanic oxygen sensor
* Pneumofathometer
* Submersible pressure gauge

Mobility
equipment|

* Diver propulsion vehicle
* Human torpedo
* Wet sub
* Diving bell
* Closed bell
* Wet bell
* Diving stage
* Swimfin
* Monofin
* PowerSwim
* Towboard

Safety
equipment|

* Alternative air source
* Octopus regulator
* Pony bottle
* Bolt snap
* Buddy line
* Dive light
* Diver's cutting tool
* Diver's knife
* Diver's telephone
* Through-water communications
* Underwater acoustic communication
* Diving bell
* Diving safety harness
* Emergency gas supply
* Bailout block
* Bailout bottle
* Lifeline
* Screw gate carabiner
* Emergency locator beacon
* Rescue tether
* Safety helmet
* Shark-proof cage
* Snoopy loop
* Navigation equipment
* Distance line
* Diving compass
* Dive reel
* Line marker
* Surface marker buoy
* Silt screw

Underwater
breathing
apparatus|

* Atmospheric diving suit
* Diving cylinder
* Burst disc
* Scuba cylinder valve
* Diving helmet
* Reclaim helmet
* Diving regulator
* Mechanism of diving regulators
* Regulator malfunction
* Regulator freeze
* Single-hose regulator
* Twin-hose regulator
* Full-face diving mask

| Open-circuit
scuba|

* Scuba set
* Bailout bottle
* Decompression cylinder
* Independent doubles
* Manifolded twin set
* Scuba manifold
* Pony bottle
* Scuba configuration
* Sidemount
* Sling cylinder

|

Diving rebreathers|

* Carbon dioxide scrubber
* Carleton CDBA
* Clearance Divers Life Support Equipment
* Cryogenic rebreather
* CUMA
* DSEA
* Dolphin
* Halcyon PVR-BASC
* Halcyon RB80
* IDA71
* Interspiro DCSC
* LAR-5
* LAR-6
* LAR-V
* LARU
* Mark IV Amphibian
* Porpoise
* Ray
* Siebe Gorman CDBA
* Salvus
* Siva

Surface-supplied
diving equipment|

* Air line
* Diver's umbilical
* Diving air compressor
* Gas panel
* Hookah
* Scuba replacement
* Snuba
* Standard diving dress

Diving
equipment
manufacturers|

* AP Diving
* Apeks
* Aqua Lung America
* Aqua Lung/La Spirotechnique
* Beuchat
* René Cavalero
* Cis-Lunar
* Cressi-Sub
* Dacor
* DESCO
* Dive Xtras
* Divex
* Diving Unlimited International
* Drägerwerk
* Faber
* Fenzy
* Maurice Fernez
* Technisub
* Oscar Gugen
* Heinke
* HeinrichsWeikamp
* Johnson Outdoors
* Mares
* Morse Diving
* Nemrod
* Oceanic Worldwide
* Porpoise
* Shearwater Research
* Siebe Gorman
* Submarine Products
* Suunto

Diving support equipment

| Access equipment|

* Boarding stirrup
* Diver lift
* Diving bell
* Diving ladder
* Diving platform (scuba)
* Diving stage
* Downline
* Jackstay
* Launch and recovery system
* Messenger line
* Moon pool

|

Breathing gas
handling|

* Air filtration
* Activated carbon
* Hopcalite
* Molecular sieve
* Silica gel
* Booster pump
* Carbon dioxide scrubber
* Cascade filling system
* Diver's pump
* Diving air compressor
* Diving air filter
* Water separator
* High pressure breathing air compressor
* Low pressure breathing air compressor
* Gas blending
* Gas blending for scuba diving
* Gas panel
* Gas reclaim system
* Gas storage bank
* Gas storage quad
* Gas storage tube
* Helium analyzer
* Nitrox production
* Membrane gas separation
* Pressure swing adsorption
* Oxygen analyser
* Electro-galvanic oxygen sensor
* Oxygen compatibility

Decompression
equipment|

* Air-lock
* Built-in breathing system
* Decompression tables
* Diving bell
* Bell cursor
* Closed bell
* Clump weight
* Launch and recovery system
* Wet bell
* Diving chamber
* Diving stage
* Recreational Dive Planner
* Saturation system

Platforms|

* Dive boat
* Canoe and kayak diving
* Combat rubber raiding craft
* Liveaboard
* Subskimmer
* Diving support vessel
* HMS Challenger (K07)

| Underwater
habitat|

* Aquarius Reef Base
* Continental Shelf Station Two
* Helgoland Habitat
* Scott Carpenter Space Analog Station
* SEALAB
* Tektite habitat

|

Remotely operated
underwater vehicles|

* 8A4-class ROUV
* ABISMO
* Atlantis ROV Team
* COTSBot
* CURV
* Deep Drone
* Épaulard
* Global Explorer ROV
* Goldfish-class ROUV
* Kaikō ROV
* Kaşif ROUV
* Long-Term Mine Reconnaissance System
* Mini Rover ROV
* OpenROV
* ROV KIEL 6000
* ROV PHOCA
* Scorpio ROV
* Sea Dragon-class ROV
* Seabed tractor
* Seafox drone
* SeaPerch
* SJT-class ROUV
* T1200 Trenching Unit
* VideoRay UROVs

Safety equipment|

* Diver down flag
* Diving shot
* ENOS Rescue-System
* Hyperbaric lifeboat
* Hyperbaric stretcher
* Jackstay
* Jonline
* Reserve gas supply

General|

* Diving spread
* Air spread
* Saturation spread
* Hot water system
* Sonar
* Underwater acoustic positioning system
* Underwater acoustic communication

Freediving

| Activities|

* Aquathlon
* Apnoea finswimming
* Freediving
* Haenyeo
* Pearl hunting
* Ama
* Snorkeling
* Spearfishing
* Underwater football
* Underwater hockey
* Underwater rugby
* Underwater target shooting

|

Competitions|

* Nordic Deep
* Vertical Blue
* Disciplines
* Constant weight (CWT)
* Constant weight bi-fins (CWTB)
* Constant weight without fins (CNF)
* Dynamic apnea (DYN)
* Dynamic apnea without fins (DNF)
* Free immersion (FIM)
* No-limits apnea (NLT)
* Static apnea (STA)
* Skandalopetra diving
* Variable weight apnea (VWT)
* Variable weight apnea without fins

Equipment|

* Diving mask
* Diving suit
* Hawaiian sling
* Polespear
* Snorkel (swimming)
* Speargun
* Swimfins
* Monofin
* Water polo cap

Freedivers|

* Deborah Andollo
* Simone Arrigoni
* Peppo Biscarini
* Michael Board
* Sara Campbell
* Derya Can Göçen
* Goran Čolak
* Carlos Coste
* Robert Croft
* Mandy-Rae Cruickshank
* Yasemin Dalkılıç
* Leonardo D'Imporzano
* Flavia Eberhard
* Şahika Ercümen
* Emma Farrell
* Francisco Ferreras
* Pierre Frolla
* Flavia Eberhard
* Mehgan Heaney-Grier
* Elisabeth Kristoffersen
* Andriy Yevhenovych Khvetkevych
* Loïc Leferme
* Enzo Maiorca
* Jacques Mayol
* Audrey Mestre
* Karol Meyer
* Kate Middleton
* Stéphane Mifsud
* Alexey Molchanov
* Natalia Molchanova
* Dave Mullins
* Patrick Musimu
* Guillaume Néry
* Herbert Nitsch
* Umberto Pelizzari
* Liv Philip
* Annelie Pompe
* Stig Severinsen
* Tom Sietas
* Martin Štěpánek
* Walter Steyn
* Tanya Streeter
* William Trubridge
* Devrim Cenk Ulusoy
* Fatma Uruk
* Danai Varveri
* Alessia Zecchini
* Nataliia Zharkova
* Kateryna Sadurska

Hazards|

* Barotrauma
* Drowning
* Freediving blackout
* Deep-water blackout
* Shallow-water blackout
* Hypercapnia
* Hypothermia

Historical|

* Ama
* Octopus wrestling
* Swimming at the 1900 Summer Olympics – Men's underwater swimming

Organisations|

* AIDA International
* Scuba Schools International
* Australian Underwater Federation
* British Freediving Association
* Confédération Mondiale des Activités Subaquatiques
* Fédération Française d'Études et de Sports Sous-Marins
* Performance Freediving International

Professional diving

| Occupations|

* Ama
* Commercial diver
* Commercial offshore diver
* Hazmat diver
* Divemaster
* Diving instructor
* Diving safety officer
* Diving superintendent
* Diving supervisor
* Haenyeo
* Media diver
* Police diver
* Public safety diver
* Scientific diver
* Underwater archaeologist

| Military
diving|

* Army engineer diver
* Canadian Armed Forces Divers
* Clearance diver
* Frogman
* Minentaucher
* Royal Navy ships diver
* United States military divers
* U.S. Navy diver
* U.S.Navy master diver

| Military
diving
units|

* 7th Marine Brigade
* Clearance Diving Branch (RAN)
* Commando Hubert
* Combat Divers Service (Lithuania)
* Comando Raggruppamento Subacquei e Incursori Teseo Tesei
* Decima Flottiglia MAS
* Frogman Corps (Denmark)
* Fuerzas Especiales
* Fukuryu
* GRUMEC
* Grup Gerak Khas
* Jagdkommando
* JW Formoza
* JW GROM
* JW Komandosów
* Kommando Spezialkräfte Marine
* KOPASKA
* MARCOS
* Marine Commandos
* Marinejegerkommandoen
* Marine Raider Regiment
* Minedykkerkommandoen
* Namibian Marine Corps Operational Diving Unit
* Naval Diving Unit (Singapore)
* Naval Service Diving Section
* Naval Special Operations Command
* Operational Diving Division (SA Navy)
* Royal Engineers
* Russian commando frogmen
* Sappers Divers Group
* Shayetet 13
* Special Air Service
* Special Air Service Regiment
* Special Actions Detachment
* Special Boat Service
* Special Boat Squadron (Sri Lanka)
* Special Forces Command (Turkey)
* Special Forces Group (Belgium)
* Special Operations Battalion (Croatia)
* Special Service Group (Navy)
* Special Warfare Diving and Salvage
* Tactical Divers Group
* US Marine Corps Force Reconnaissance
* US Marine Corps Reconnaissance Battalions
* US Navy SEALs
* Underwater Construction Teams
* Underwater Demolition Command
* Underwater Demolition Team
* Underwater Offence (Turkish Armed Forces)
* UNGERIN

|

Underwater
work|

* Commercial offshore diving
* Dive leader
* Diver training
* Recreational diver training
* Hazmat diving
* Hyperbaric welding
* Marine construction
* Offshore construction
* Underwater construction
* Media diving
* Pearl hunting
* Police diving
* Potable water diving
* Public safety diving
* Scientific diving
* Ships husbandry
* Sponge diving
* Submarine pipeline
* Underwater archaeology
* Archaeology of shipwrecks
* Underwater cutting and welding
* Underwater demolition
* Underwater inspection
* Nondestructive testing
* Underwater logging
* Underwater photography
* Underwater search and recovery
* Underwater searches
* Underwater videography
* Underwater survey

| Salvage diving|

* SS Egypt
* Kronan
* La Belle
* SS Laurentic
* RMS Lusitania
* Mars
* Mary Rose
* USS Monitor
* HMS Royal George
* Vasa

|

Diving
contractors|

* COMEX
* Helix Energy Solutions Group
* International Marine Contractors Association

Tools and
equipment|

* Abrasive waterjet
* Airlift
* Baited remote underwater video
* In-water surface cleaning
* Brush cart
* Cavitation cleaning
* Pressure washing
* Pigging
* Hot stab
* Lifting bag
* Remotely operated underwater vehicle
* Thermal lance
* Tremie
* Water jetting

Underwater
weapons|

* Limpet mine
* Speargun
* Hawaiian sling
* Polespear

| Underwater
firearm|

* Gyrojet
* Mk 1 Underwater Defense Gun
* Powerhead
* Underwater pistols
* Heckler & Koch P11
* SPP-1 underwater pistol
* Underwater revolvers
* AAI underwater revolver
* Underwater rifles
* ADS amphibious rifle
* APS underwater rifle
* ASM-DT amphibious rifle
* QBS-06

|

Recreational diving

* Recreational dive sites
* Index of recreational dive sites
* List of wreck diving sites
* Outline of recreational dive sites

| Specialties|

* Altitude diving
* Cave diving
* Deep diving
* Ice diving
* Muck diving
* Open-water diving
* Rebreather diving
* Sidemount diving
* Solo diving
* Technical diving
* Underwater photography
* Wreck diving

|

Diver
organisations|

* British Sub-Aqua Club (BSAC)
* Cave Divers Association of Australia (CDAA)
* Cave Diving Group (CDG)
* Comhairle Fo-Thuinn (CFT)
* Confédération Mondiale des Activités Subaquatiques (CMAS)
* Federación Española de Actividades Subacuáticas (FEDAS)
* Fédération Française d'Études et de Sports Sous-Marins (FFESSM)
* International Association for Handicapped Divers (IAHD)
* Quintana Roo Speleological Survey (QRSS)
* Woodville Karst Plain Project (WKPP)

Diving tourism
industry|

* Dive center
* Diving in Timor-Leste
* Diving in the Maldives
* Environmental impact of recreational diving
* Scuba diving tourism
* Scuba diving in the Cayman Islands
* Shark tourism
* Sinking ships for wreck diving sites
* Underwater diving in Guam

Diving events
and festivals|

* Diversnight
* Underwater Bike Race

Diving safety

* Human factors in diving equipment design
* Human factors in diving safety
* Life-support system
* Safety-critical system
* Scuba diving fatalities
* Underwater diving emergency
* Water safety
* Water surface searches

| Diving
hazards|

* List of diving hazards and precautions
* Environmental
* Current
* Delta-P
* Entanglement hazard
* Overhead
* Silt out
* Wave action
* Equipment
* Freeflow
* Use of breathing equipment in an underwater environment
* Failure of diving equipment other than breathing apparatus
* Single point of failure
* Physiological
* Cold shock response
* Decompression
* Nitrogen narcosis
* Oxygen toxicity
* Seasickness
* Uncontrolled decompression
* Diver behaviour and competence
* Incompetence
* Overconfidence effect
* Panic
* Task loading
* Trait anxiety
* Willful violation

| Consequences|

* Barotrauma
* Decompression sickness
* Drowning
* Hypothermia
* Hypoxia
* Hypercapnia
* Hyperthermia
* Non-freezing cold injury

|

Diving
procedures|

* Ascending and descending
* Emergency ascent
* Boat diving
* Canoe and kayak diving
* Buddy diving
* buddy check
* Decompression
* Decompression practice
* Pyle stop
* Ratio decompression
* Dive briefing
* Dive log
* Dive planning
* Rule of thirds
* Scuba gas planning
* Diver communications
* Diver rescue
* Diver training
* Doing It Right
* Drift diving
* Gas blending for scuba diving
* Night diving
* Rebreather diving
* Scuba gas management
* Solo diving
* Wall diving

Risk
management|

* Checklist
* Hazard identification and risk assessment
* Hazard analysis
* Job safety analysis
* Risk assessment
* Hyperbaric evacuation and rescue
* Risk control
* Hierarchy of hazard controls
* Incident pit
* Lockout–tagout
* Permit To Work
* Redundancy
* Safety data sheet
* Situation awareness

| Diving team|

* Bellman
* Chamber operator
* Diver medical technician
* Diver's attendant
* Diving supervisor
* Diving systems technician
* Gas man
* Life support technician
* Stand-by diver

|

Equipment
safety|

* Breathing gas quality
* Testing and inspection of diving cylinders
* Hydrostatic test
* Sustained load cracking
* Diving regulator
* Breathing performance of regulators

Occupational
safety and
health|

* Association of Diving Contractors International
* International Marine Contractors Association
* Code of practice
* Contingency plan
* Diving regulations
* Emergency response plan
* Diving safety officer
* Diving superintendent
* Diving supervisor
* Operations manual
* Standard operating procedure

Diving medicine

| Diving
disorders|

* List of signs and symptoms of diving disorders
* Cramp
* Motion sickness
* Surfer's ear

| Pressure
related|

* Alternobaric vertigo
* Barostriction
* Barotrauma
* Air embolism
* Aerosinusitis
* Barodontalgia
* Dental barotrauma
* Middle ear barotrauma
* Pulmonary barotrauma
* Compression arthralgia
* Decompression illness
* Dysbarism

| Oxygen|

* Freediving blackout
* Hyperoxia
* Hypoxia
* Oxygen toxicity

|

Inert gases|

* Avascular necrosis
* Decompression sickness
* Dysbaric osteonecrosis
* Inner ear decompression sickness
* Isobaric counterdiffusion
* Taravana
* High-pressure nervous syndrome
* Hydrogen narcosis
* Nitrogen narcosis

Carbon dioxide|

* Hypercapnia
* Hypocapnia

Breathing gas
contaminants|

* Carbon monoxide poisoning

Immersion
related|

* Asphyxia
* Drowning
* Hypothermia
* Immersion diuresis
* Instinctive drowning response
* Laryngospasm
* Salt water aspiration syndrome
* Swimming-induced pulmonary edema

Treatment|

* Demand valve oxygen therapy
* First aid
* Hyperbaric medicine
* Hyperbaric treatment schedules
* In-water recompression
* Oxygen therapy
* Therapeutic recompression

Personnel|

* Diving Medical Examiner
* Diving Medical Practitioner
* Diving Medical Technician
* Hyperbaric nursing

Screening|

* Atrial septal defect
* Effects of drugs on fitness to dive
* Fitness to dive
* Psychological fitness to dive

Research|

| Researchers in
diving physiology
and medicine|

* Arthur J. Bachrach
* Albert R. Behnke
* Peter B. Bennett
* Paul Bert
* George F. Bond
* Robert Boyle
* Alf O. Brubakk
* Albert A. Bühlmann
* John R. Clarke
* Guybon Chesney Castell Damant
* Kenneth William Donald
* William Paul Fife
* John Scott Haldane
* Robert William Hamilton Jr.
* Henry Valence Hempleman
* Leonard Erskine Hill
* Brian Andrew Hills
* Felix Hoppe-Seyler
* Christian J. Lambertsen
* Simon Mitchell
* Charles Momsen
* Neal W. Pollock
* John Rawlins
* Charles Wesley Shilling
* Edward D. Thalmann
* Jacques Triger

|

Diving medical
research
organisations|

* Aerospace Medical Association
* Divers Alert Network (DAN)
* Diving Diseases Research Centre (DDRC)
* Diving Medical Advisory Council (DMAC)
* European Diving Technology Committee (EDTC)
* European Underwater and Baromedical Society (EUBS)
* National Board of Diving and Hyperbaric Medical Technology
* Naval Submarine Medical Research Laboratory
* Royal Australian Navy School of Underwater Medicine
* Rubicon Foundation
* South Pacific Underwater Medicine Society (SPUMS)
* Undersea and Hyperbaric Medical Society (UHMS)
* United States Navy Experimental Diving Unit (NEDU)

Law

* Civil liability in recreational diving
* Diving regulations
* Duty of care
* List of legislation regulating underwater diving
* Investigation of diving accidents
* Convention on the Protection of the Underwater Cultural Heritage

History of underwater diving

* History of decompression research and development
* History of dive computers
* History of Diving Museum
* History of scuba diving
* List of researchers in underwater diving
* Lyons Maritime Museum
* Man in the Sea Museum
* Timeline of atmospheric diving suits
* Timeline of diving technology
* Pearling in Western Australia
* US Navy decompression models and tables

| Archeological
sites|

* SS Commodore
* USS Monitor
* Queen Anne's Revenge
* Whydah Gally

|

Underwater art
and artists|

* The Diver
* Jason deCaires Taylor

Engineers
and inventors|

* Jerónimo de Ayanz y Beaumont
* William Beebe
* Georges Beuchat
* Giovanni Alfonso Borelli
* Joseph-Martin Cabirol
* John R. Clarke
* Jacques Cousteau
* Charles Anthony Deane
* John Deane
* Louis de Corlieu
* Auguste Denayrouze
* Ted Eldred
* Henry Fleuss
* Émile Gagnan
* Karl Heinrich Klingert
* Peter Kreeft
* Christian J. Lambertsen
* Yves Le Prieur
* John Lethbridge
* Ernest William Moir
* Joseph Salim Peress
* Auguste Piccard
* Joe Savoie
* Willard Franklyn Searle
* Gordon Smith
* Augustus Siebe
* Pierre-Marie Touboulic
* Jacques Triger

Historical
equipment|

* Aqua-Lung
* RV Calypso
* SP-350 Denise
* Magnesium torch
* Nikonos
* Porpoise regulator
* Standard diving dress
* Sub Marine Explorer
* Vintage scuba

| Diver
propulsion
vehicles|

* Advanced SEAL Delivery System
* Cosmos CE2F series
* Dry Combat Submersible
* Human torpedo
* Motorised Submersible Canoe
* Necker Nymph
* R-2 Mala-class swimmer delivery vehicle
* SEAL Delivery Vehicle
* Shallow Water Combat Submersible
* Siluro San Bartolomeo
* Welfreighter
* Wet Nellie

|

Military and
covert operations|

* Raid on Alexandria (1941)
* Sinking of the Rainbow Warrior

Scientific projects|

* 1992 cageless shark-diving expedition
* Mission 31

Awards and events|

* Hans Hass Award
* International Scuba Diving Hall of Fame
* London Diving Chamber Dive Lectures
* NOGI Awards
* Women Divers Hall of Fame

Incidents|

| Dive boat incidents|

* Sinking of MV Conception

|

Diver rescues|

* Alpazat cave rescue
* Tham Luang cave rescue

Early diving|

* John Day (carpenter)
* Charles Spalding
* Ebenezer Watson

Freediving fatalities|

* Stephen Keenan
* Loïc Leferme
* Audrey Mestre
* Nicholas Mevoli
* Natalia Molchanova

Offshore
diving incidents|

* Byford Dolphin diving bell accident
* Drill Master diving accident
* Star Canopus diving accident
* Stena Seaspread diving accident
* Venture One diving accident
* Waage Drill II diving accident
* Wildrake diving accident

Professional
diving fatalities|

* Roger Baldwin
* John Bennett
* Victor F. Guiel Jr.
* Francis P. Hammerberg
* Craig M. Hoffman
* Peter Henry Michael Holmes
* Johnson Sea Link accident
* Edwin Clayton Link
* Gerard Anthony Prangley
* Per Skipnes
* Robert John Smyth
* Albert D. Stover
* Richard A. Walker
* Lothar Michael Ward
* Joachim Wendler
* Bradley Westell
* Arne Zetterström

Scuba diving
fatalities|

* 1973 Mount Gambier cave diving accident
* Ricardo Armbruster
* Allan Bridge
* David Bright
* Berry L. Cannon
* Cotton Coulson
* Cláudio Coutinho
* E. Yale Dawson
* Deon Dreyer
* Milan Dufek
* Sheck Exley
* Maurice Fargues
* Fernando Garfella Palmer
* Guy Garman
* Steve Irwin
* death
* Jim Jones
* Henry Way Kendall
* Artur Kozłowski
* Yuri Lipski
* Kirsty MacColl
* Linnea Mills
* Agnes Milowka
* François de Roubaix
* Chris and Chrissy Rouse
* Dave Shaw
* Wesley C. Skiles
* Dewey Smith
* Rob Stewart
* Esbjörn Svensson
* Josef Velek

Publications

| Manuals|

* NOAA Diving Manual
* U.S. Navy Diving Manual
* Basic Cave Diving: A Blueprint for Survival
* Underwater Handbook
* Bennett and Elliott's physiology and medicine of diving
* Encyclopedia of Recreational Diving
* The new science of skin and scuba diving
* Professional Diver's Handbook
* Basic Scuba

|

Standards and
Codes of Practice|

* Code of Practice for Scientific Diving (UNESCO)
* DIN 7876
* IMCA Code of Practice for Offshore Diving
* ISO 24801 Recreational diving services — Requirements for the training of recreational scuba divers

General non-fiction|

* The Darkness Beckons
* Goldfinder
* The Last Dive
* Shadow Divers
* The Silent World: A Story of Undersea Discovery and Adventure

Research|

* List of Divers Alert Network publications

Dive guides|

Training and registration

| Diver
training|

* Competence and assessment
* Competency-based learning
* Refresher training
* Skill assessment
* Diver training standard
* Diving instructor
* Diving school
* Occupational diver training
* Commercial diver training
* Military diver training
* Public safety diver training
* Scientific diver training
* Recreational diver training
* Introductory diving
* ISO training standards
* Teaching method
* Muscle memory
* Overlearning
* Stress exposure training

| Skills|

* Combat sidestroke
* Diver navigation
* Diver trim
* Ear clearing
* Frenzel maneuver
* Valsalva maneuver
* Finning techniques
* Scuba skills
* Buddy breathing
* Low impact diving
* Diamond Reef System
* Surface-supplied diving skills
* Underwater searches

|

Recreational
scuba
certification
levels|

| Core diving skills|

* Advanced Open Water Diver
* Autonomous diver
* CMAS* scuba diver
* CMAS** scuba diver
* Introductory diving
* Low Impact Diver
* Master Scuba Diver
* Open Water Diver
* Supervised diver

|

Leadership skills|

* Dive leader
* Divemaster
* Diving instructor
* Master Instructor

Specialist skills|

* Rescue Diver
* Solo diver

Diver training
certification
and registration
organisations|

* European Underwater Federation (EUF)
* International Diving Regulators and Certifiers Forum (IDRCF)
* International Diving Schools Association (IDSA)
* International Marine Contractors Association (IMCA)
* List of diver certification organizations
* National Oceanic and Atmospheric Administration (NOAA)
* Nautical Archaeology Society
* Recreational diver course referral
* World Recreational Scuba Training Council (WRSTC)

| Commercial diver
certification
authorities|

* Australian Diver Accreditation Scheme (ADAS)
* Commercial diver registration in South Africa
* Divers Institute of Technology
* Health and Safety Executive (HSE)
* Department of Employment and Labour

|

Commercial diving
schools|

* Divers Academy International
* Norwegian diver school

Free-diving
certification
agencies|

* AIDA International (AIDA)
* Confédération Mondiale des Activités Subaquatiques (CMAS)
* Performance Freediving International (PI)
* Scuba Schools International (SSI)

Recreational
scuba
certification
agencies|

* American Canadian Underwater Certifications (ACUC)
* American Nitrox Divers International (ANDI)
* Association nationale des moniteurs de plongée (ANMP)
* British Sub-Aqua Club (BSAC)
* Comhairle Fo-Thuinn (CFT)
* Confédération Mondiale des Activités Subaquatiques (CMAS)
* Federación Española de Actividades Subacuáticas (FEDAS)
* Fédération Française d'Études et de Sports Sous-Marins (FFESSM)
* Federazione Italiana Attività Subacquee (FIAS)
* Global Underwater Explorers (GUE)
* International Association for Handicapped Divers (IAHD)
* International Association of Nitrox and Technical Divers (IANTD)
* International Life Saving Federation (ILS)
* Israeli Diving Federation (TIDF)
* National Academy of Scuba Educators (NASE)
* National Association of Underwater Instructors (NAUI)
* Nederlandse Onderwatersport Bond (NOB)
* Professional Association of Diving Instructors (PADI)
* Professional Diving Instructors Corporation (PDIC)
* Professional Technical and Recreational Diving (ProTec)
* Rebreather Association of International Divers (RAID)
* Sub-Aqua Association (SAA)
* Scuba Diving International (SDI)
* Scuba Educators International (SEI)
* Scuba Schools International (SSI)
* Türkiye Sualtı Sporları Federasyonu (TSSF)
* United Diving Instructors (UDI)
* YMCA SCUBA Program

Scientific diver
certification
authorities|

* American Academy of Underwater Sciences (AAUS)
* CMAS Scientific Committee

Technical diver
certification
agencies|

* American Nitrox Divers International (ANDI)
* British Sub-Aqua Club (BSAC)
* Confédération Mondiale des Activités Subaquatiques (CMAS)
* Diving Science and Technology (DSAT)
* Federazione Italiana Attività Subacquee (FIAS)
* International Association of Nitrox and Technical Divers (IANTD)
* Professional Association of Diving Instructors (PADI)
* Professional Diving Instructors Corporation (PDIC)
* Professional Technical and Recreational Diving (ProTec)
* Rebreather Association of International Divers (RAID)
* Trimix Scuba Association (TSA)
* Technical Extended Range (TXR)

| Cave
diving|

* Cave Divers Association of Australia (CDAA)
* Cave Diving Group (CDG)
* Global Underwater Explorers (GUE)
* National Speleological Society#Cave Diving Group (CDG)
* National Association of Underwater Instructors (NAUI)
* Technical Diving International (TDI)

|

Military diver
training centres|

* Defence Diving School
* Navy Diving Salvage and Training Center
* Underwater Escape Training Unit

Military diver
training courses|

* United States Marine Corps Combatant Diver Course

Underwater sports

| Surface snorkeling|

* Finswimming

|

Snorkeling/breath-hold|

* Spearfishing
* Underwater football
* Underwater hockey
* Australia
* Turkey
* Underwater rugby
* Colombia
* United States
* Underwater target shooting

Breath-hold|

* Aquathlon
* Apnoea finswimming
* Freediving

Open Circuit Scuba|

* Immersion finswimming
* Sport diving
* Underwater cycling
* Underwater orienteering
* Underwater photography

Rebreather|

* Underwater photography

Sports governing
organisations
and federations|

* International
* AIDA International
* Confédération Mondiale des Activités Subaquatiques)
* National
* AIDA Hellas
* Australian Underwater Federation
* British Freediving Association
* British Octopush Association
* British Underwater Sports Association
* Comhairle Fo-Thuinn
* Federación Española de Actividades Subacuáticas
* Fédération Française d'Études et de Sports Sous-Marins
* South African Underwater Sports Federation
* Türkiye Sualtı Sporları Federasyonu
* Underwater Society of America)

Competitions|

* 14th CMAS Underwater Photography World Championship
* Underwater Hockey World Championships
* Underwater Orienteering World Championships
* Underwater Rugby World Championships

Underwater divers

| Pioneers
of diving|

* Eduard Admetlla i Lázaro
* Aquanaut
* Mary Bonnin
* Amelia Behrens-Furniss
* James F. Cahill
* Jacques Cousteau
* Billy Deans
* Dottie Frazier
* Trevor Hampton
* Hans Hass
* Hannes Keller
* Dick Rutkowski
* Teseo Tesei
* Arne Zetterström

|

Underwater
scientists
archaeologists and
environmentalists|

* Michael Arbuthnot
* Robert Ballard
* George Bass
* Mensun Bound
* Louis Boutan
* Jeffrey Bozanic
* Hugh Bradner
* Cathy Church
* Eugenie Clark
* James P. Delgado
* Sylvia Earle
* John Christopher Fine
* George R. Fischer
* Anders Franzén
* Honor Frost
* Fernando Garfella Palmer
* David Gibbins
* Graham Jessop
* Swietenia Puspa Lestari
* Pilar Luna
* Robert F. Marx
* Anna Marguerite McCann
* Innes McCartney
* Charles T. Meide
* Mark M. Newell
* Lyuba Ognenova-Marinova
* John Peter Oleson
* Mendel L. Peterson
* Richard Pyle
* Andreas Rechnitzer
* William R. Royal
* Margaret Rule
* Gunter Schöbel
* Stephanie Schwabe
* Myriam Seco
* E. Lee Spence
* Robert Sténuit
* Peter Throckmorton
* Cristina Zenato

Scuba record
holders|

* Pascal Bernabé
* Jim Bowden
* Mark Ellyatt
* Sheck Exley
* Nuno Gomes
* Claudia Serpieri
* Krzysztof Starnawski

Underwater
filmmakers
and presenters|

* Samir Alhafith
* David Attenborough
* Ramón Bravo
* Jean-Michel Cousteau
* Richie Kohler
* Paul Rose
* Andy Torbet
* Ivan Tors
* Andrew Wight
* James Cameron

Underwater
photographers|

* Doug Allan
* Tamara Benitez
* Georges Beuchat
* Adrian Biddle
* Jonathan Bird
* Eric Cheng
* Neville Coleman
* Jacques Cousteau
* John D. Craig
* Ben Cropp
* Bernard Delemotte
* David Doubilet
* Candice Farmer
* John Christopher Fine
* Rodney Fox
* Ric Frazier
* Stephen Frink
* Peter Gimbel
* Monty Halls
* Hans Hass
* Henry Way Kendall
* Rudie Kuiter
* Joseph B. MacInnis
* Luis Marden
* Agnes Milowka
* Noel Monkman
* Pete Oxford
* Steve Parish
* Zale Parry
* Pierre Petit
* Leni Riefenstahl
* Peter Scoones
* Brian Skerry
* Wesley C. Skiles
* E. Lee Spence
* Philippe Tailliez
* Ron Taylor
* Valerie Taylor
* Albert Tillman
* John Veltri
* Stan Waterman
* Michele Westmorland
* John Ernest Williamson
* J. Lamar Worzel

Underwater
explorers|

* Caves
* Graham Balcombe
* Sheck Exley
* Martyn Farr
* Jochen Hasenmayer
* Jill Heinerth
* Jarrod Jablonski
* Brian Kakuk
* William Hogarth Main
* Tom Mount
* Jack Sheppard
* Bill Stone
* Reefs
* Arthur C. Clarke
* Wrecks
* Leigh Bishop
* John Chatterton
* Clive Cussler
* Bill Nagle
* Valerie van Heest
* Aristotelis Zervoudis

Aquanauts|

* Andrew Abercromby
* Joseph M. Acaba
* Clayton Anderson
* Richard R. Arnold
* Serena Auñón-Chancellor
* Michael Barratt (astronaut)
* Robert A. Barth
* Robert L. Behnken
* Randolph Bresnik
* Timothy J. Broderick
* Justin Brown
* Berry L. Cannon
* Scott Carpenter
* Gregory Chamitoff
* Steve Chappell
* Catherine Coleman
* Robin Cook
* Craig B. Cooper
* Fabien Cousteau
* Philippe Cousteau
* Timothy Creamer
* Jonathan Dory
* Pedro Duque
* Sylvia Earle
* Jeanette Epps
* Sheck Exley
* Albert Falco
* Andrew J. Feustel
* Michael Fincke
* Satoshi Furukawa
* Ronald J. Garan Jr.
* Michael L. Gernhardt
* Christopher E. Gerty
* David Gruber
* Chris Hadfield
* Jeremy Hansen
* José M. Hernández
* John Herrington
* Paul Hill
* Akihiko Hoshide
* Mark Hulsbeck
* Emma Hwang
* Norishige Kanai
* Les Kaufman
* Scott Kelly
* Karen Kohanowich
* Timothy Kopra
* Dominic Landucci
* Jon Lindbergh
* Kjell N. Lindgren
* Michael López-Alegría
* Joseph B. MacInnis
* Sandra Magnus
* Thomas Marshburn
* Matthias Maurer
* K. Megan McArthur
* Craig McKinley
* Jessica Meir
* Simone Melchior
* Dorothy Metcalf-Lindenburger
* Andreas Mogensen
* Karen Nyberg
* John D. Olivas
* Takuya Onishi
* Luca Parmitano
* Nicholas Patrick
* Tim Peake
* Thomas Pesquet
* Marc Reagan
* Garrett Reisman
* Kathleen Rubins
* Dick Rutkowski
* Tara Ruttley
* David Saint-Jacques
* Josef Schmid
* Robert Sheats
* Dewey Smith
* Steve Squyres
* Heidemarie Stefanyshyn-Piper
* Robert Sténuit
* Hervé Stevenin
* Nicole Stott
* James Talacek
* Daniel M. Tani
* Robert Thirsk
* Bill Todd
* Mark T. Vande Hei
* Koichi Wakata
* Rex J. Walheim
* Shannon Walker
* John Morgan Wells
* Joachim Wendler
* Douglas H. Wheelock
* Peggy Whitson
* Dafydd Williams
* Jeffrey Williams
* Sunita Williams
* Reid Wiseman
* Kimiya Yui

Writers and journalists|

* Michael C. Barnette
* Victor Berge
* Philippe Diolé
* Gary Gentile
* Bret Gilliam
* Bob Halstead
* Hillary Hauser
* Trevor Jackson
* Steve Lewis
* John Mattera

Rescuers|

* Craig Challen
* Richard Harris
* Rick Stanton
* John Volanthen

Frogmen|

* Lionel Crabb
* Ian Edward Fraser
* Sydney Knowles
* James Joseph Magennis

Commercial salvors|

* Keith Jessop

Science of underwater diving

* List of researchers in underwater diving

| Diving
physics|

* Metre sea water
* Neutral buoyancy
* Underwater acoustics
* Modulated ultrasound
* Underwater vision
* Underwater computer vision

|

Diving
physiology|

* Blood shift
* Cold shock response
* Diving reflex
* Equivalent narcotic depth
* Maximum operating depth
* Physiological response to water immersion
* Thermal balance of the underwater diver
* Underwater vision
* Work of breathing

| Decompression
theory|

* Decompression models:
* Bühlmann decompression algorithm
* Haldane's decompression model
* Reduced gradient bubble model
* Thalmann algorithm
* Thermodynamic model of decompression
* Varying Permeability Model
* Equivalent air depth
* Oxygen window
* Physiology of decompression

|

Diving
environments|

* Underwater exploration
* Deep-sea exploration

| Classification|

* List of diving environments by type
* Altitude diving
* Benign water diving
* Confined water diving
* Deep diving
* Inland diving
* Inshore diving
* Muck diving
* Night diving
* Open-water diving
* Black-water diving
* Blue-water diving
* Penetration diving
* Cave diving
* Torricellian chamber
* Ice diving
* Wreck diving
* Recreational dive sites
* Underwater environment
* Underwater diving environment

|

Impact|

* Environmental impact of recreational diving
* Low impact diving

Other

* Bathysphere
* Defense against swimmer incursions
* Diver detection sonar
* Offshore survey
* Rugged compact camera
* Underwater domain awareness
* Underwater vehicle

| Deep-submergence
vehicle|

* Aluminaut
* DSV Alvin
* American submarine NR-1
* Bathyscaphe
* Archimède
* FNRS-2
* FNRS-3
* Harmony class bathyscaphe
* Sea Pole-class bathyscaphe
* Trieste II
* Deepsea Challenger
* Ictineu 3
* JAGO
* Jiaolong
* Konsul-class submersible
* Limiting Factor
* Russian submarine Losharik
* Mir
* Nautile
* Pisces-class deep submergence vehicle
* DSV Sea Cliff
* DSV Shinkai
* DSV Shinkai 2000
* DSV Shinkai 6500
* DSV Turtle
* DSV-5 Nemo

|

Submarine rescue|

* International Submarine Escape and Rescue Liaison Office
* Submarine Escape and Rescue system (Royal Swedish Navy)
* McCann Rescue Chamber
* Submarine rescue ship

| Deep-submergence
rescue vehicle|

* LR5
* LR7
* MSM-1
* Mystic-class deep-submergence rescue vehicle
* DSRV-1 Mystic
* DSRV-2 Avalon
* NATO Submarine Rescue System
* Priz-class deep-submergence rescue vehicle
* Russian deep submergence rescue vehicle AS-28
* Russian submarine AS-34
* ASRV Remora
* SRV-300
* Submarine Rescue Diving Recompression System
* Type 7103 DSRV
* URF (Swedish Navy)

|

Submarine escape|

* Escape trunk
* Submarine escape training facility
* Submarine Escape Training Facility (Australia)

| Escape set|

* Davis Submerged Escape Apparatus
* Momsen lung
* Steinke hood
* Submarine Escape Immersion Equipment

|

Special
interest
groups|

* Artificial Reef Society of British Columbia
* CMAS Europe
* Coral Reef Alliance
* Divers Alert Network
* Green Fins
* Finger Lakes Underwater Preserve Association
* Karst Underwater Research
* Nautical Archaeology Program
* Nautical Archaeology Society
* Naval Air Command Sub Aqua Club
* PADI AWARE
* Reef Check
* Reef Life Survey
* Rubicon Foundation
* Save Ontario Shipwrecks
* SeaKeys
* Sea Research Society
* Society for Underwater Historical Research
* Society for Underwater Technology
* Underwater Archaeology Branch, Naval History & Heritage Command

Neutral buoyancy
facilities for
Astronaut training|

* Neutral Buoyancy Laboratory
* Neutral buoyancy pool
* Neutral buoyancy simulation as a training aid
* Neutral Buoyancy Simulator
* Space Systems Laboratory
* Yuri Gagarin Cosmonaut Training Center

Other|

* Nautilus Productions
* Helicopter Aircrew Breathing Device
* Scuba diving therapy
* Seabed mining

* Category
* Commons
* Glossary
* Indexes: Dive sites
* Divers
* Diving
* Outline
* Portal

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