Misplaced Pages

#598401

85-470: The Oneida Number One Tunnel is the only source of acid mine drainage to Sugarloaf Creek. The Oneida Number One Tunnel has a treatment system. This treatment system causes water from the tunnel to flow through an oxic limestone drain, increasing its pH and raising its concentration of alkalinity . Before the installation of the treatment system, the pH of the Oneida Number One Tunnel had

170-572: A cascade method, Swiss chemist and physicist Raoul Pierre Pictet evaporated liquid sulfur dioxide in order to liquefy carbon dioxide, which in turn was evaporated to cool oxygen gas enough to liquefy it. He sent a telegram on December 22, 1877, to the French Academy of Sciences in Paris announcing his discovery of liquid oxygen . Just two days later, French physicist Louis Paul Cailletet announced his own method of liquefying molecular oxygen. Only

255-630: A colorless and odorless diatomic gas with the chemical formula O 2 . Dioxygen gas currently constitutes 20.95% molar fraction of the Earth's atmosphere , though this has changed considerably over long periods of time in Earth's history . Oxygen makes up almost half of the Earth's crust in the form of various oxides such as water , carbon dioxide , iron oxides and silicates . All eukaryotic organisms , including plants , animals , fungi , algae and most protists , need oxygen for cellular respiration , which extracts chemical energy by

340-434: A few drops of the liquid were produced in each case and no meaningful analysis could be conducted. Oxygen was liquefied in a stable state for the first time on March 29, 1883, by Polish scientists from Jagiellonian University , Zygmunt Wróblewski and Karol Olszewski . In 1891 Scottish chemist James Dewar was able to produce enough liquid oxygen for study. The first commercially viable process for producing liquid oxygen

425-481: A light sky-blue color caused by absorption in the red (in contrast with the blue color of the sky, which is due to Rayleigh scattering of blue light). High-purity liquid O 2 is usually obtained by the fractional distillation of liquefied air. Liquid oxygen may also be condensed from air using liquid nitrogen as a coolant. Liquid oxygen is a highly reactive substance and must be segregated from combustible materials. The spectroscopy of molecular oxygen

510-560: A major role in absorbing energy from singlet oxygen and converting it to the unexcited ground state before it can cause harm to tissues. The common allotrope of elemental oxygen on Earth is called dioxygen , O 2 , the major part of the Earth's atmospheric oxygen (see Occurrence ). O 2 has a bond length of 121  pm and a bond energy of 498  kJ/mol . O 2 is used by complex forms of life, such as animals, in cellular respiration . Other aspects of O 2 are covered in

595-444: A number of natural factors, but is most often a concern as a consequence of pollution and eutrophication in which plant nutrients enter a river, lake, or ocean, and phytoplankton blooms are encouraged. While phytoplankton, through photosynthesis , will raise DO saturation during daylight hours, the dense population of a bloom reduces DO saturation during the night by respiration . When phytoplankton cells die, they sink towards

680-445: A pH ranging from 4.6 to 4.2. The alkalinity was 0 milligrams per liter and the acidity ranged from 40 to 50 milligrams per liter. The tunnel had trace amounts of iron and an aluminum concentration of 1.4 to 4.9 milligrams per liter. Following the installation of the treatment system was installed on the Oneida Number One Tunnel, the pH of the tunnel's waters averages 6.5. The alkalinity ranges from 9 to 26 milligrams per liter and

765-438: A part of air that he called spiritus nitroaereus . In one experiment, he found that placing either a mouse or a lit candle in a closed container over water caused the water to rise and replace one-fourteenth of the air's volume before extinguishing the subjects. From this, he surmised that nitroaereus is consumed in both respiration and combustion. Mayow observed that antimony increased in weight when heated, and inferred that

850-404: A process called eutrophication and the decay of these organisms and other biomaterials may reduce the O 2 content in eutrophic water bodies. Scientists assess this aspect of water quality by measuring the water's biochemical oxygen demand , or the amount of O 2 needed to restore it to a normal concentration. Paleoclimatologists measure the ratio of oxygen-18 and oxygen-16 in

935-458: A small proportion of manganese dioxide. Oxygen levels in the atmosphere are trending slightly downward globally, possibly because of fossil-fuel burning. At standard temperature and pressure , oxygen is a colorless, odorless, and tasteless gas with the molecular formula O 2 , referred to as dioxygen. As dioxygen , two oxygen atoms are chemically bound to each other. The bond can be variously described based on level of theory, but

SECTION 10

#1732875850599

1020-449: A triplet electronic ground state . An electron configuration with two unpaired electrons, as is found in dioxygen orbitals (see the filled π* orbitals in the diagram) that are of equal energy—i.e., degenerate —is a configuration termed a spin triplet state. Hence, the ground state of the O 2 molecule is referred to as triplet oxygen . The highest-energy, partially filled orbitals are antibonding , and so their filling weakens

1105-508: Is associated with the atmospheric processes of aurora and airglow . The absorption in the Herzberg continuum and Schumann–Runge bands in the ultraviolet produces atomic oxygen that is important in the chemistry of the middle atmosphere. Excited-state singlet molecular oxygen is responsible for red chemiluminescence in solution. Table of thermal and physical properties of oxygen (O 2 ) at atmospheric pressure: Naturally occurring oxygen

1190-469: Is composed of three stable isotopes , O , O , and O , with O being the most abundant (99.762% natural abundance ). Most O is synthesized at the end of the helium fusion process in massive stars but some is made in the neon burning process . O is primarily made by the burning of hydrogen into helium during the CNO cycle , making it a common isotope in the hydrogen burning zones of stars. Most O

1275-475: Is formed, removing even more oxygen from the environment in the forms of carbon dioxide, bicarbonate ions, and carbonate. Dissolved inorganic carbon is made at a rate of 2.3–6.5 mg/(m ⋅day). As phytoplankton breakdown, free phosphorus and nitrogen become available in the environment, which also fosters hypoxic conditions. As the breakdown of this phytoplankton takes place, the more phosphorus turns into phosphates, and nitrogens turn into nitrates. This depletes

1360-496: Is near the border between East Union Township, Schuylkill County; North Union Township, Schuylkill County , and Black Creek Township, Luzerne County . The tunnel is located in the Eagle Rock Resort. The tunnel is a rock tunnel that causes water to flow from mines in its upper reaches via gravity. The Oneida Number One Tunnel is the second-largest source of acid mine drainage in the watershed of Catawissa Creek. The opening of

1445-630: Is often given for Priestley because his work was published first. Priestley, however, called oxygen "dephlogisticated air", and did not recognize it as a chemical element. The name oxygen was coined in 1777 by Antoine Lavoisier , who first recognized oxygen as a chemical element and correctly characterized the role it plays in combustion. Common industrial uses of oxygen include production of steel , plastics and textiles , brazing, welding and cutting of steels and other metals , rocket propellant , oxygen therapy , and life support systems in aircraft , submarines , spaceflight and diving . One of

1530-425: Is problematic for air-breathing organisms, yet it is essential for many anaerobic organisms. Hypoxia applies to many situations, but usually refers to the atmosphere and natural waters. Atmospheric hypoxia occurs naturally at high altitudes . Total atmospheric pressure decreases as altitude increases, causing a lower partial pressure of oxygen, which is defined as hypobaric hypoxia. Oxygen remains at 20.9% of

1615-441: Is produced when N (made abundant from CNO burning) captures a He nucleus, making O common in the helium-rich zones of evolved, massive stars . Fifteen radioisotopes have been characterized, ranging from O to O. The most stable are O with a half-life of 122.24 seconds and O with a half-life of 70.606 seconds. All of the remaining radioactive isotopes have half-lives that are less than 27 seconds and

1700-408: Is reasonably and simply described as a covalent double bond that results from the filling of molecular orbitals formed from the atomic orbitals of the individual oxygen atoms, the filling of which results in a bond order of two. More specifically, the double bond is the result of sequential, low-to-high energy, or Aufbau , filling of orbitals, and the resulting cancellation of contributions from

1785-456: Is released as a byproduct . Oxygen is too chemically reactive to remain a free element in air without being continuously replenished by the photosynthetic activities of autotrophs such as cyanobacteria , chloroplast -bearing algae and plants. A much rarer triatomic allotrope of oxygen , ozone ( O 3 ), strongly absorbs the UVB and UVC wavelengths and forms a protective ozone layer at

SECTION 20

#1732875850599

1870-761: Is substantial. In these areas a so-called " dead zone " can be created. Low dissolved oxygen conditions are often seasonal, as is the case in Hood Canal and areas of Puget Sound , in Washington State. The World Resources Institute has identified 375 hypoxic coastal zones around the world, concentrated in coastal areas in Western Europe, the Eastern and Southern coasts of the US, and East Asia, particularly in Japan. Hypoxia may also be

1955-712: Is temperature-dependent, and about twice as much ( 14.6  mg/L ) dissolves at 0 °C than at 20 °C ( 7.6  mg/L ). At 25 °C and 1 standard atmosphere (101.3  kPa ) of air, freshwater can dissolve about 6.04  milliliters  (mL) of oxygen per liter , and seawater contains about 4.95 mL per liter. At 5 °C the solubility increases to 9.0 mL (50% more than at 25 °C) per liter for freshwater and 7.2 mL (45% more) per liter for sea water. Oxygen condenses at 90.20  K (−182.95 °C, −297.31 °F) and freezes at 54.36 K (−218.79 °C, −361.82 °F). Both liquid and solid O 2 are clear substances with

2040-436: Is termed anaerobic, reducing , or anoxic . In water, oxygen levels are approximately 7 ppm or 0.0007% in good quality water, but fluctuate. Many organisms require hypoxic conditions. Oxygen is poisonous to anaerobic bacteria for example. Oxygen depletion is typically expressed as a percentage of the oxygen that would dissolve in the water at the prevailing temperature and salinity. A system with low concentration—in

2125-495: Is the amount of particulate organic carbon (POC) overall at a given time, t. G(0) is the concentration of POC before breakdown takes place. k is a rate constant in year-1, and t is time in years. For most POC of phytoplankton, the k is around 12.8 years-1, or about 28 days for nearly 96% of carbon to be broken down in these systems. Whereas for anoxic systems, POC breakdown takes 125 days, over four times longer. It takes approximately 1 mg of oxygen to break down 1 mg of POC in

2210-435: Is the result of the oxygen cycle . This biogeochemical cycle describes the movement of oxygen within and between its three main reservoirs on Earth: the atmosphere, the biosphere, and the lithosphere . The main driving factor of the oxygen cycle is photosynthesis , which is responsible for modern Earth's atmosphere. Photosynthesis releases oxygen into the atmosphere, while respiration , decay , and combustion remove it from

2295-457: Is unusual among the planets of the Solar System in having such a high concentration of oxygen gas in its atmosphere: Mars (with 0.1% O 2 by volume) and Venus have much less. The O 2 surrounding those planets is produced solely by the action of ultraviolet radiation on oxygen-containing molecules such as carbon dioxide. The unusually high concentration of oxygen gas on Earth

2380-517: Is usually given priority in the discovery. The French chemist Antoine Laurent Lavoisier later claimed to have discovered the new substance independently. Priestley visited Lavoisier in October 1774 and told him about his experiment and how he liberated the new gas. Scheele had also dispatched a letter to Lavoisier on September 30, 1774, which described his discovery of the previously unknown substance, but Lavoisier never acknowledged receiving it (a copy of

2465-608: The Earth , the Moon , Mars , and meteorites , but were long unable to obtain reference values for the isotope ratios in the Sun , believed to be the same as those of the primordial solar nebula . Analysis of a silicon wafer exposed to the solar wind in space and returned by the crashed Genesis spacecraft has shown that the Sun has a higher proportion of oxygen-16 than does the Earth. The measurement implies that an unknown process depleted oxygen-16 from

2550-556: The Greek roots ὀξύς (oxys) ( acid , literally 'sharp', from the taste of acids) and -γενής (-genēs) (producer, literally begetter), because he mistakenly believed that oxygen was a constituent of all acids. Chemists (such as Sir Humphry Davy in 1812) eventually determined that Lavoisier was wrong in this regard, but by then the name was too well established. Oxygen entered the English language despite opposition by English scientists and

2635-484: The blood and carbon dioxide out, and the body's circulatory system then transports the oxygen to other tissues where cellular respiration takes place. However in insects , the most successful and biodiverse terrestrial clade , oxygen is directly conducted to the internal tissues via a deep network of airways . Many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins , nucleic acids , carbohydrates and fats , as do

Oneida Number One Tunnel - Misplaced Pages Continue

2720-440: The chalcogen group in the periodic table , a highly reactive nonmetal , and a potent oxidizing agent that readily forms oxides with most elements as well as with other compounds . Oxygen is the most abundant element in Earth's crust , and the third-most abundant element in the universe after hydrogen and helium . At standard temperature and pressure , two oxygen atoms will bind covalently to form dioxygen ,

2805-465: The reaction of oxygen with organic molecules derived from food and releases carbon dioxide as a waste product. In aquatic animals , dissolved oxygen in water is absorbed by specialized respiratory organs called gills , through the skin or via the gut ; in terrestrial animals such as tetrapods , oxygen in air is actively taken into the body via specialized organs known as lungs , where gas exchange takes place to diffuse oxygen into

2890-470: The shells and skeletons of marine organisms to determine the climate millions of years ago (see oxygen isotope ratio cycle ). Seawater molecules that contain the lighter isotope , oxygen-16, evaporate at a slightly faster rate than water molecules containing the 12% heavier oxygen-18, and this disparity increases at lower temperatures. During periods of lower global temperatures, snow and rain from that evaporated water tends to be higher in oxygen-16, and

2975-430: The thermal decomposition of potassium nitrate . In Bugaj's view, the isolation of oxygen and the proper association of the substance to that part of air which is required for life, provides sufficient evidence for the discovery of oxygen by Sendivogius. This discovery of Sendivogius was however frequently denied by the generations of scientists and chemists which succeeded him. It is also commonly claimed that oxygen

3060-553: The 17th and the 18th century but none of them recognized it as a chemical element . This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory , which was then the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher , and modified by the chemist Georg Ernst Stahl by 1731, phlogiston theory stated that all combustible materials were made of two parts. One part, called phlogiston,

3145-531: The 2s electrons, after sequential filling of the low σ and σ orbitals; σ overlap of the two atomic 2p orbitals that lie along the O–O molecular axis and π overlap of two pairs of atomic 2p orbitals perpendicular to the O–O molecular axis, and then cancellation of contributions from the remaining two 2p electrons after their partial filling of the π orbitals. This combination of cancellations and σ and π overlaps results in dioxygen's double-bond character and reactivity, and

3230-527: The American scientist Robert H. Goddard became the first person to develop a rocket engine that burned liquid fuel; the engine used gasoline for fuel and liquid oxygen as the oxidizer . Goddard successfully flew a small liquid-fueled rocket 56 m at 97 km/h on March 16, 1926, in Auburn, Massachusetts , US. In academic laboratories, oxygen can be prepared by heating together potassium chlorate mixed with

3315-488: The Natural Resource Conservation Service. The treatment system has significantly reduced the effect of acid mine drainage on Sugarloaf Creek. The total cost of the system was $ 375,000. 40°55′32″N 76°07′25″W  /  40.9256°N 76.1236°W  / 40.9256; -76.1236 Oxic Hypoxia ( hypo : "below", oxia : "oxygenated") refers to low oxygen conditions. Hypoxia

3400-752: The North Green Mountain Coal Basin and is the only tunnel to drain this basin. The tunnel is located in the middle reaches of the watershed of Catawissa Creek. It discharges into Sugarloaf Creek near Lake Choctaw and Lake Susquehanna . The elevation of the Oneida Number One Tunnel is 510 feet (160 m) above sea level . The tunnel discharges its water into a narrow and deep draw approximately 670 feet (200 m) from Sugarloaf Creek. The tunnel begins in coal mining land in East Union Township, Schuylkill County . It flows north-northwest, crossing under Tomhicken Creek to its other end, which

3485-483: The Oneida Number One Tunnel was collapsed as early as the 1970s. There are recreational lakes both upstream and downstream of the point where the Oneida Number One Tunnel discharges into Sugarloaf Creek. The total maximum daily load document for Catawissa Creek suggests reclaiming mined land in the Green Mountain Coal Basin to reduce the discharge of the Oneida Number One Tunnel. The construction of

Oneida Number One Tunnel - Misplaced Pages Continue

3570-760: The Oneida Number One Tunnel was completed in the 1930s. It was one of five mine drainage tunnels in the Catawissa Creek watershed to be constructed during this decade (the others being the Audenried Tunnel , the Catawissa Tunnel , the Green Mountain Tunnel , and the Oneida Number Three Tunnel ). A treatment system was constructed for the Oneida Number One Tunnel in July 2001. The treatment system

3655-478: The Philosopher's Stone drawn from the source of nature and manual experience"] (1604) described a substance contained in air, referring to it as 'cibus vitae' (food of life, ) and according to Polish historian Roman Bugaj, this substance is identical with oxygen. Sendivogius, during his experiments performed between 1598 and 1604, properly recognized that the substance is equivalent to the gaseous byproduct released by

3740-438: The Sun's disk of protoplanetary material prior to the coalescence of dust grains that formed the Earth. Oxygen presents two spectrophotometric absorption bands peaking at the wavelengths 687 and 760  nm . Some remote sensing scientists have proposed using the measurement of the radiance coming from vegetation canopies in those bands to characterize plant health status from a satellite platform. This approach exploits

3825-471: The acidity is 0 milligrams per liter. The iron concentration is 0 milligrams per liter and the concentration of aluminum has decreased to 0.70 milligrams per liter. The treatment system has significantly improved the water quality of Lake Choctaw , Sugarloaf Creek, and Tomhicken Creek. Prior to the installation of the treatment system on the Oneida Number One Tunnel, its discharge ranged from 560 to 3000 gallons per minute. The Oneida Number One Tunnel drains

3910-493: The atmosphere. In the present equilibrium, production and consumption occur at the same rate. Free oxygen also occurs in solution in the world's water bodies. The increased solubility of O 2 at lower temperatures (see Physical properties ) has important implications for ocean life, as polar oceans support a much higher density of life due to their higher oxygen content. Water polluted with plant nutrients such as nitrates or phosphates may stimulate growth of algae by

3995-412: The bond order from three to two. Because of its unpaired electrons, triplet oxygen reacts only slowly with most organic molecules, which have paired electron spins; this prevents spontaneous combustion. In the triplet form, O 2 molecules are paramagnetic . That is, they impart magnetic character to oxygen when it is in the presence of a magnetic field, because of the spin magnetic moments of

4080-429: The bottom and are decomposed by bacteria , a process that further reduces DO in the water column. If oxygen depletion progresses to hypoxia, fish kills can occur and invertebrates like worms and clams on the bottom may be killed as well. Hypoxia may also occur in the absence of pollutants. In estuaries, for example, because freshwater flowing from a river into the sea is less dense than salt water, stratification in

4165-444: The diatomic elemental molecules in those gases. The first commercial method of producing oxygen was chemical, the so-called Brin process involving a reversible reaction of barium oxide . It was invented in 1852 and commercialized in 1884, but was displaced by newer methods in early 20th century. By the late 19th century scientists realized that air could be liquefied and its components isolated by compressing and cooling it. Using

4250-466: The electron spins are paired. It is much more reactive with common organic molecules than is normal (triplet) molecular oxygen. In nature, singlet oxygen is commonly formed from water during photosynthesis, using the energy of sunlight. It is also produced in the troposphere by the photolysis of ozone by light of short wavelength and by the immune system as a source of active oxygen. Carotenoids in photosynthetic organisms (and possibly animals) play

4335-542: The environment depends on the presence of oxygen, and once oxygen is no longer in the bodies of water, ligninperoxidases cannot continue to break down the lignin. When oxygen is not present in the water, the time required for breakdown of phytoplankton changes from 10.7 days to a total of 160 days. The rate of phytoplankton breakdown can be represented using this equation: G ( t ) = G ( 0 ) e − k t {\displaystyle G(t)=G(0)e^{-kt}} In this equation, G(t)

SECTION 50

#1732875850599

4420-601: The environment, and therefore, hypoxia takes place quickly as oxygen is used up quickly to digest POC. About 9% of POC in phytoplankton can be broken down in a single day at 18 °C. Therefore, it takes about eleven days to completely break down phytoplankton. After POC is broken down, this particulate matter can be turned into other dissolved carbon, such as carbon dioxide, bicarbonate ions, and carbonate. As much as 30% of phytoplankton can be broken down into dissolved carbon. When this particulate organic carbon interacts with 350 nm ultraviolet light, dissolved inorganic carbon

4505-511: The explanation for periodic phenomena such as the Mobile Bay jubilee , where aquatic life suddenly rushes to the shallows, perhaps trying to escape oxygen-depleted water. Recent widespread shellfish kills near the coasts of Oregon and Washington are also blamed on cyclic dead zone ecology. Phytoplankton are mostly made up of lignin and cellulose, which are broken down by oxidative mechanism, which consume oxygen. The breakdown of phytoplankton in

4590-563: The fact that the Englishman Priestley had first isolated the gas and written about it. This is partly due to a poem praising the gas titled "Oxygen" in the popular book The Botanic Garden (1791) by Erasmus Darwin , grandfather of Charles Darwin . John Dalton 's original atomic hypothesis presumed that all elements were monatomic and that the atoms in compounds would normally have the simplest atomic ratios with respect to one another. For example, Dalton assumed that water's formula

4675-399: The first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium . In his work Pneumatica , Philo observed that inverting a vessel over a burning candle and surrounding the vessel's neck with water resulted in some water rising into the neck. Philo incorrectly surmised that parts of the air in

4760-399: The idea; instead, it was based on observations of what happens when something burns, that most common objects appear to become lighter and seem to lose something in the process. Polish alchemist , philosopher , and physician Michael Sendivogius (Michał Sędziwój) in his work De Lapide Philosophorum Tractatus duodecim e naturae fonte et manuali experientia depromti ["Twelve Treatises on

4845-499: The letter was found in Scheele's belongings after his death). Lavoisier conducted the first adequate quantitative experiments on oxidation and gave the first correct explanation of how combustion works. He used these and similar experiments, all started in 1774, to discredit the phlogiston theory and to prove that the substance discovered by Priestley and Scheele was a chemical element . In one experiment, Lavoisier observed that there

4930-552: The lower stratosphere , which shields the biosphere from ionizing ultraviolet radiation . However, ozone present at the surface is a corrosive byproduct of smog and thus an air pollutant . Oxygen was isolated by Michael Sendivogius before 1604, but it is commonly believed that the element was discovered independently by Carl Wilhelm Scheele , in Uppsala , in 1773 or earlier, and Joseph Priestley in Wiltshire , in 1774. Priority

5015-423: The major constituent inorganic compounds of animal shells, teeth, and bone. Most of the mass of living organisms is oxygen as a component of water, the major constituent of lifeforms. Oxygen in Earth's atmosphere is produced by biotic photosynthesis , in which photon energy in sunlight is captured by chlorophyll to split water molecules and then react with carbon dioxide to produce carbohydrates and oxygen

5100-428: The majority of these have half-lives that are less than 83 milliseconds. The most common decay mode of the isotopes lighter than O is β decay to yield nitrogen, and the most common mode for the isotopes heavier than O is beta decay to yield fluorine . Oxygen is the most abundant chemical element by mass in the Earth's biosphere , air, sea and land. Oxygen is the third most abundant chemical element in

5185-494: The nitroaereus must have combined with it. He also thought that the lungs separate nitroaereus from air and pass it into the blood and that animal heat and muscle movement result from the reaction of nitroaereus with certain substances in the body. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract "De respiratione". Robert Hooke , Ole Borch , Mikhail Lomonosov , and Pierre Bayen all produced oxygen in experiments in

SECTION 60

#1732875850599

5270-406: The oxygen even more so in the environment, further creating hypoxic zones in higher quantities. As more minerals such as phosphorus and nitrogen are displaced into these aquatic systems, the growth of phytoplankton greatly increases, and after their death, hypoxic zones are formed. Oxygen Oxygen is a chemical element with the symbol   O and atomic number 8. It is a member of

5355-455: The range between 1 and 30% saturation—is called hypoxic or dysoxic . Most fish cannot live below 30% saturation since they rely on oxygen to derive energy from their nutrients. Hypoxia leads to impaired reproduction of remaining fish via endocrine disruption . A "healthy" aquatic environment should seldom experience less than 80% saturation. The exaerobic zone is found at the boundary of anoxic and hypoxic zones. Hypoxia can occur throughout

5440-455: The remainder of this article. Trioxygen ( O 3 ) is usually known as ozone and is a very reactive allotrope of oxygen that is damaging to lung tissue. Ozone is produced in the upper atmosphere when O 2 combines with atomic oxygen made by the splitting of O 2 by ultraviolet (UV) radiation. Since ozone absorbs strongly in the UV region of the spectrum , the ozone layer of

5525-414: The seawater left behind tends to be higher in oxygen-18. Marine organisms then incorporate more oxygen-18 into their skeletons and shells than they would in a warmer climate. Paleoclimatologists also directly measure this ratio in the water molecules of ice core samples as old as hundreds of thousands of years. Planetary geologists have measured the relative quantities of oxygen isotopes in samples from

5610-405: The surface. Hypolimnetic oxygen depletion can lead to both summer and winter "kills". During summer stratification , inputs or organic matter and sedimentation of primary producers can increase rates of respiration in the hypolimnion . If oxygen depletion becomes extreme, aerobic organisms, like fish, may die, resulting in what is known as a "summer kill". The same phenomena can occur in

5695-465: The total gas mixture, differing from hypoxic hypoxia , where the percentage of oxygen in the air (or blood) is decreased. This is common in the sealed burrows of some subterranean animals, such as blesmols . Atmospheric hypoxia is also the basis of altitude training , which is a standard part of training for elite athletes. Several companies mimic hypoxia using normobaric artificial atmosphere . An aquatic system lacking dissolved oxygen (0% saturation)

5780-486: The universe, after hydrogen and helium. About 0.9% of the Sun 's mass is oxygen. Oxygen constitutes 49.2% of the Earth's crust by mass as part of oxide compounds such as silicon dioxide and is the most abundant element by mass in the Earth's crust . It is also the major component of the world's oceans (88.8% by mass). Oxygen gas is the second most common component of the Earth's atmosphere , taking up 20.8% of its volume and 23.1% of its mass (some 10 tonnes). Earth

5865-401: The unpaired electrons in the molecule, and the negative exchange energy between neighboring O 2 molecules. Liquid oxygen is so magnetic that, in laboratory demonstrations, a bridge of liquid oxygen may be supported against its own weight between the poles of a powerful magnet. Singlet oxygen is a name given to several higher-energy species of molecular O 2 in which all

5950-435: The upper atmosphere functions as a protective radiation shield for the planet. Near the Earth's surface, it is a pollutant formed as a by-product of automobile exhaust . At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft . The metastable molecule tetraoxygen ( O 4 ) was discovered in 2001, and was assumed to exist in one of the six phases of solid oxygen . It

6035-451: The vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philo's work by observing that a portion of air is consumed during combustion and respiration . In the late 17th century, Robert Boyle proved that air is necessary for combustion. English chemist John Mayow (1641–1679) refined this work by showing that fire requires only

6120-441: The water column and also at high altitudes as well as near sediments on the bottom. It usually extends throughout 20–50% of the water column, but depends on the water depth and location of pycnoclines (rapid changes in water density with depth). It can occur in 10–80% of the water column. For example, in a 10-meter water column, it can reach up to 2 meters below the surface. In a 20-meter water column, it can extend up to 8 meters below

6205-527: The water column can result. Vertical mixing between the water bodies is therefore reduced, restricting the supply of oxygen from the surface waters to the more saline bottom waters. The oxygen concentration in the bottom layer may then become low enough for hypoxia to occur. Areas particularly prone to this include shallow waters of semi-enclosed water bodies such as the Waddenzee or the Gulf of Mexico , where land run-off

6290-435: The winter, but for different reasons. During winter, ice and snow cover can attenuate light, and therefore reduce rates of photosynthesis. The freezing over of a lake also prevents air-water interactions that allow the exchange of oxygen. This creates a lack of oxygen while respiration continues. When the oxygen becomes badly depleted, anaerobic organisms can die, resulting in a "winter kill". Oxygen depletion can result from

6375-428: Was HO, leading to the conclusion that the atomic mass of oxygen was 8 times that of hydrogen, instead of the modern value of about 16. In 1805, Joseph Louis Gay-Lussac and Alexander von Humboldt showed that water is formed of two volumes of hydrogen and one volume of oxygen; and by 1811 Amedeo Avogadro had arrived at the correct interpretation of water's composition, based on what is now called Avogadro's law and

6460-919: Was built by the Catawissa Creek Restoration Association and a number of other organizations. These organizations included the Schuylkill County Conservation District, the Columbia County Conservation District, the Office of Surface Mining, the landowners of the Double Diamond Development Corporation, the Eagle Rock Homeowner's Association, the Eastern Pennsylvania Council on Abandoned Mine Reclamation, and

6545-408: Was first discovered by Swedish pharmacist Carl Wilhelm Scheele . He had produced oxygen gas by heating mercuric oxide (HgO) and various nitrates in 1771–72. Scheele called the gas "fire air" because it was then the only known agent to support combustion. He wrote an account of this discovery in a manuscript titled Treatise on Air and Fire , which he sent to his publisher in 1775. That document

6630-451: Was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx . Highly combustible materials that leave little residue , such as wood or coal, were thought to be made mostly of phlogiston; non-combustible substances that corrode, such as iron, contained very little. Air did not play a role in phlogiston theory, nor were any initial quantitative experiments conducted to test

6715-491: Was independently developed in 1895 by German engineer Carl von Linde and British engineer William Hampson . Both men lowered the temperature of air until it liquefied and then distilled the component gases by boiling them off one at a time and capturing them separately. Later, in 1901, oxyacetylene welding was demonstrated for the first time by burning a mixture of acetylene and compressed O 2 . This method of welding and cutting metal later became common. In 1923,

6800-445: Was no overall increase in weight when tin and air were heated in a closed container. He noted that air rushed in when he opened the container, which indicated that part of the trapped air had been consumed. He also noted that the tin had increased in weight and that increase was the same as the weight of the air that rushed back in. This and other experiments on combustion were documented in his book Sur la combustion en général , which

6885-462: Was not sensibly different from that of common air , but I fancied that my breast felt peculiarly light and easy for some time afterwards." Priestley published his findings in 1775 in a paper titled "An Account of Further Discoveries in Air", which was included in the second volume of his book titled Experiments and Observations on Different Kinds of Air . Because he published his findings first, Priestley

6970-408: Was proven in 2006 that this phase, created by pressurizing O 2 to 20  GPa , is in fact a rhombohedral O 8 cluster . This cluster has the potential to be a much more powerful oxidizer than either O 2 or O 3 and may therefore be used in rocket fuel . A metallic phase was discovered in 1990 when solid oxygen is subjected to a pressure of above 96 GPa and it

7055-499: Was published in 1777. In the meantime, on August 1, 1774, an experiment conducted by the British clergyman Joseph Priestley focused sunlight on mercuric oxide contained in a glass tube, which liberated a gas he named "dephlogisticated air". He noted that candles burned brighter in the gas and that a mouse was more active and lived longer while breathing it. After breathing the gas himself, Priestley wrote: "The feeling of it to my lungs

7140-458: Was published in 1777. In that work, he proved that air is a mixture of two gases; 'vital air', which is essential to combustion and respiration, and azote (Gk. ἄζωτον "lifeless"), which did not support either. Azote later became nitrogen in English, although it has kept the earlier name in French and several other European languages. Lavoisier renamed 'vital air' to oxygène in 1777 from

7225-420: Was shown in 1998 that at very low temperatures, this phase becomes superconducting . Oxygen dissolves more readily in water than nitrogen, and in freshwater more readily than in seawater. Water in equilibrium with air contains approximately 1 molecule of dissolved O 2 for every 2 molecules of N 2 (1:2), compared with an atmospheric ratio of approximately 1:4. The solubility of oxygen in water

#598401