Underwater is a term describing the realm below the surface of water Water is the ubiquitous chemical substance, composed of hydrogen and oxygen, that is essential for the survival of many known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface. On Earth, it where the water exists in a natural feature (called a body of water Water is the ubiquitous chemical substance, composed of hydrogen and oxygen, that is essential for the survival of many known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface. On Earth, it) such as an ocean An ocean (from Greek Ωκεανός, Okeanos ) is a major body of Seawater (salt water). The Earth's oceans cover approximately 71% of the Earth's surface, 361,000,000 square kilometres (139,000,000 sq mi), and can be as deep as of 10,923 metres (6.787 mi). Scientists estimate that 230,000 marine life forms of all types are currently known, but, sea The term sea refers to certain large amounts of water, but there is inconsistency as to its precise definition and application. Most commonly, a sea may refer to a large expanse of saline water connected with an ocean, but it is also used sometimes for a large saline lake that lacks a natural outlet, e.g. the Caspian Sea. Colloquially, the term is, lake A lake is a terrain feature (or physical feature), a body of liquid on the surface of a world that is localized to the bottom of basin (another type of landform or terrain feature; that is, it is not global) and moves slowly if it moves at all. On Earth, a body of water is considered a lake when it is inland, not part of the ocean, is larger and, pond A pond is an inland body of standing water, either natural or man-made, that is smaller than a lake. A wide variety of man-made bodies of water are classified as ponds, including water gardens designed for aesthetic ornamentation, fish ponds designed for commercial fish breeding, and solar ponds designed to store thermal energy, or river A river is a natural watercourse, usually freshwater, flowing toward an ocean, a lake, a sea or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including stream, creek, brook, rivulet, and rill; there is no. Three quarters of the planet Earth Earth is the third planet from the Sun. It is the fifth largest of the eight planets in the solar system, and the largest of the terrestrial planets in the Solar System in terms of diameter, mass and density. It is also referred to as the World, the Blue Planet,[note 3] and Terra.[note 4] is covered by water. A majority of the planet's solid surface is abyssal plain Abyssal plains are flat or very gently sloping areas of the deep ocean basin floor. They are among the Earth's flattest and smoothest regions and the least explored. Abyssal plains cover approximately 40% of the ocean floor and reach depths between 2,200 and 5,500 m . They generally lie between the foot of a continental rise and a mid-oceanic, at depths between 4000 and 5500 m (13,000 to 18,000 ft) below the surface of the oceans. The solid surface location on the planet closest to the center of the orb is the Challenger Deep, located in the Mariana Trench The Mariana Trench is the deepest part of the world's oceans, and the deepest location on the surface of the Earth's crust. It is located in the western Pacific Ocean, to the east of the Mariana Islands. The trench is about 1580 miles (2550 km) long but has a mean width of only 43 miles (69 km). It reaches a maximum depth of about 10,924 meters at at a depth of 10,924 m (35,838 ft) under the sea.
History
Although a number of human A human is a member of a species of bipedal primates in the family Hominidae . Mitochondrial DNA and fossil evidence indicates that modern humans evolved in east Africa about 200,000 years ago. When compared to other animals and primates, humans have a highly developed brain, capable of abstract reasoning, language, introspection and problem activities are conducted underwater—such as research, scuba diving Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater for recreation, commercial or industrial reasons. Unlike early diving, which relied exclusively on air pumped from the surface, scuba divers carry their own source of breathing gas (usually compressed air), allowing them greater freedom than with an for work Professional Diving is a type of diving where the divers are paid for their work. There are several branches of professional diving, the most well known of which is probably commercial diving. Any person wishing to become a professional diver normally requires specific training that satisfies any regulatory agencies which have local authority, or recreation Recreational diving or sport diving is a type of diving that uses SCUBA equipment for the purpose of leisure and enjoyment. In some diving circles, the term "recreational diving" is used in contradistinction to "technical diving", a more demanding aspect of the sport which requires greater levels of training, experience and, or even underwater warfare with submarines A submarine is a watercraft capable of independent operation below water. It differs from a submersible, which has only limited underwater capability. The term submarine most commonly refers to large crewed autonomous vessels; however, historically or more casually, submarine can also refer to medium sized or smaller vessels , Remotely Operated—this very extensive environment on planet Earth Earth is the third planet from the Sun. It is the fifth largest of the eight planets in the solar system, and the largest of the terrestrial planets in the Solar System in terms of diameter, mass and density. It is also referred to as the World, the Blue Planet,[note 3] and Terra.[note 4] is hostile to humans in many ways and therefore little explored.
An immediate obstacle to human activity under water is the fact that human lungs The lung or pulmonary system is the essential respiration organ in air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located in the chest on either side of the heart. Their principal function is to transport oxygen from the atmosphere into the bloodstream, cannot naturally function in this environment. Unlike the gills A gill is an anatomical structure found in many aquatic organisms. It is a respiration organ whose function is the extraction of oxygen from water and the excretion of carbon dioxide. The microscopic structure of a gill is such that it presents a very large surface area to the external environment of fish A fish is any aquatic vertebrate animal that is typically ectothermic , covered with scales, and equipped with two sets of paired fins and several unpaired fins. Fish are abundant in the sea and in fresh water, with species being known from mountain streams (e.g., char and gudgeon) as well as in the deepest depths of the ocean (e.g., gulpers and, human lungs The lung or pulmonary system is the essential respiration organ in air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located in the chest on either side of the heart. Their principal function is to transport oxygen from the atmosphere into the bloodstream, are adapted to the exchange of gases In physics, a gas is a state of matter, consisting of a collection of particles without a definite shape or volume that are in more or less random motion at atmospheric pressure Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure, not liquids Liquid is one of the principal states of matter. A liquid is a fluid that has the particles loose and can freely form a distinct surface at the boundaries of its bulk material. The surface is a free surface where the liquid is not constrained by a container. Aside from simply having insufficient musculature to rapidly move water in and out of the lungs, a more significant problem for all air breathing animals, such as mammals Mammals are a class of vertebrate animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair, three middle ear bones used in hearing, and a neocortex region in the brain and birds Birds are winged, bipedal, endothermic (warm-blooded), vertebrate animals that lay eggs. There are around 10,000 living species, making them the most numerous tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Birds range in size from the 5 cm (2 in) Bee Hummingbird to the 3 m (10 ft) Ostrich. The, is that water contains so little dissolved oxygen Oxygen (pronounced /ˈɒksɨdʒɨn/, from the Greek roots ὀξύς (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O. It is a member of the chalcogen group on the periodic table, and is a highly reactive compared with atmospheric air The Earth's atmosphere is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night. Dry air contains roughly (by volume) 78.08% nitrogen, 20.95. Air is around 21% O2; water typically is less than 0.001% dissolved oxygen.
The density The density of a material is defined as its mass per unit volume. The symbol of density is ρ of water also causes problems that increase dramatically with depth. The atmospheric pressure Atmospheric pressure is sometimes defined as the force per unit area exerted against a surface by the weight of air above that surface at any given point in the Earth's atmosphere. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Low pressure at the surface is 14.7 PSI or around 100 kPa. A comparable water pressure occurs at a depth of only 10 m (33 ft.) (9.8 m (32 ft) for sea water.) Thus, at about 10 m below the surface the water exerts twice the pressure (2 atmospheres or 200 kPa) on the body as air at surface level.
For solid objects like our bones and muscles, this added pressure is not much of a problem; but it is a problem for any air-filled spaces like the mouth The mouth, buccal cavity, or oral cavity is the first portion of the alimentary canal that receives food and begins digestion by mechanically breaking up the solid food particles into smaller pieces and mixing them with saliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth, ears The ear is the organ that detects sound. The vertebrate ear shows a common biology from fish to humans, with variations in structure according to order and species. It not only acts as a receiver for sound, but plays a major role in the sense of balance and body position. The ear is part of the auditory system, paranasal sinuses Paranasal sinuses form developmentally through excavation of bone by air-filled sacs from the nasal cavity. This process begins prenatally, and it continues through the course of an organism's lifetime and lungs. This is because the air in those spaces reduces in volume when under pressure and so does not provide those spaces with support from the higher outside pressure. Even at a depth of 8 feet (2.5 m) underwater, an inability to equalize air pressure in the middle ear The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear has also been called the tympanic cavity, or cavum with outside water pressure can cause pain, and the tympanic membrane The tympanic membrane , is a thin membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air to the ossicles inside the middle ear. The malleus bone bridges the gap between the eardrum and the other ossicles. Rupture or perforation of the eardrum can lead to conductive hearing loss can rupture at depths under 10 ft (3 m). The danger of pressure damage is greatest in shallow water because the rate of pressure change is greatest at the surface of the water. For example the pressure increase between the surface and 10 m (33 ft) is 100% (100 kPa to 200 kPa), but the pressure increase from 30 m (100 ft) to 40 m (130 ft) is only 25% (400 kPa to 500 kPa).
Any object immersed in water is provided with a buoyant In physics, buoyancy is the upward force that keeps things afloat. The net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body. This force enables the object to float or at least seem lighter force that counters the force of gravity Gravitation is a natural phenomenon by which objects with mass attract one another. In everyday life, gravitation is most commonly thought of as the agency which lends weight to objects with mass. Gravitation compels dispersed matter to coalesce, thus accounting for the existence of the Earth, the Sun, and most of the macroscopic objects in the, appearing to make the object less heavy. If the overall density of the object exceeds the density of water, the object sinks. If the overall density is less than the density of water, the object rises until it floats on the surface.
Note the bluish cast given to objects in this underwater photo of pillow lava. (NOAA The National Oceanic and Atmospheric Administration (NOAA, pronounced /ˈno.ə/, like "noah") is a scientific agency within the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. NOAA warns of dangerous weather, charts seas and skies, guides the use and protection of ocean and coastal)With increasing depth underwater, sunlight Sunlight, in the broad sense, is the total spectrum of the electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon. Near the poles in summer, the days are longer and the nights are shorter or non-existent. In the winter is absorbed, and the amount of visible light Light is electromagnetic radiation, particularly radiation of a wavelength that is visible to the human eye . In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not diminishes. Because absorption is greater for long wavelengths In physics, the wavelength of a sinusoidal wave is the spatial period of the wave – the distance over which the wave's shape repeats. It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a characteristic of both traveling waves and (red end of the visible spectrum The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to 750 nm. In terms of frequency, this corresponds to a band in the vicinity of 790–400) than for short wavelengths (blue end of the visible spectrum), the colour spectrum The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to 750 nm. In terms of frequency, this corresponds to a band in the vicinity of 790–400 is rapidly altered with increasing depth. White objects at the surface appear bluish underwater, and red objects appear dark, even black. Although light penetration will be less if water is turbid Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality, in the very clear water of the open ocean less than 25% of the surface light reaches a depth of 10 m (33 feet). At 100 m (330 ft) the light present from the sun is about 0.5% of that at the surface.
The euphotic depth The photic zone or euphotic zone is the depth of the water in a lake or ocean, that is exposed to sufficient sunlight for photosynthesis to occur. The depth of the photic zone can be greatly affected by seasonal turbidity. It extends from the atmosphere-water interface downwards to a depth where light intensity falls to 1% of that at the surface ( is the depth at which light intensity falls to 1% of the value at the surface. This depth is dependent upon water clarity, being only a few meters underwater in a turbid estuary, but may reach 200 meters in the open ocean. At the euphotic depth, plants (such as phytoplankton Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words phyton, or "plant", and πλαγκτος , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye. However, when present in high enough numbers, they may) have no net energy gain from photosynthesis and thus cannot grow.
At depths greater than a few hundred meters, the sun has little effect on water temperature, because the sun's energy has been absorbed by water at the surface. In the great depths of the ocean the water temperature is very cold. In fact, 75% of the water in the world ocean (the great depths) has a temperature between 0 °C and 2 °C.
Water conducts In physics, thermal conductivity, k, is the property of a material that indicates its ability to conduct heat. It appears primarily in Fourier's Law for heat conduction heat around twenty five times more efficiently than air. Hypothermia Hypothermia is a condition in which an organism's temperature drops below that required for normal metabolism and bodily functions. In warm-blooded animals, core body temperature is maintained near a constant level through biologic homeostasis. However, when the body is exposed to cold, its internal mechanisms may be unable to replenish the heat, a potentially fatal condition, occurs when the human body's core temperature falls below 35 °C. Insulating the body's warmth from water is the main purpose of diving suits Apart from hot water suits, these types of suit are not exclusively used by divers but are often used for thermal protection by people engaged in other water sports activities such as surfing, sailing, powerboating, windsurfing, kite surfing, waterskiing, caving and swimming and exposure suits when used in water temperatures below 25 °C.
Sound Sound is a travelling wave which is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations is transmitted about 4.5 times faster in water (about 1435 m/s in fresh water) as it is in air (330 m/s). The human brain can determine the direction of sound in air by detecting small differences in the time it takes for sound waves in air to reach each of the two ears. For these reasons divers find it difficult to determine the direction of sound underwater.
See also
- Timeline of underwater technology
- Underwater photography Underwater photography is the process of taking photographs while under water. It is usually done while scuba diving, but can be done while snorkeling or swimming
- Underwater acoustics
- List of all Wikipedia pages whose names start with "Underwater"
- "Underwater" may appear as a possible computer-translation misrendering of Unterwasser, a village in Switzerland
References
- Dueker, C. W. 1970, Medical aspects of sport diving. A.S. Barnes and Co., New York. 232 pp.
- The Briny Deep – Oceanography notes at San Jose State University.
Categories: Environments | Oceanography | Underwater diving
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Q. What kind of study/degree do you need to work at aquariums (swimming with dolphins and etc) or work with studying things underwater (like scuba diving and whatnot) and what are those people called? Marine Biologists?
Asked by waffles. - Tue Feb 24 15:29:59 2009 - - 2 Answers - 0 Comments
A. Marine Biologists, Marine Mammal Trainer, Marine Ecologist, Aquarist, Aquaculture Researcher, Conservation Scientists, etc There are a few different jobs that fit your description. Try looking through some job listings to see the education requirements. You could also try contacting aquariums for info on jobs. Other links you may find useful:
Answered by Heather H - Tue Feb 24 16:00:04 2009
