1.
Death Valley
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Death Valley is a desert valley located in Eastern California. It is one of the hottest places in the world at the height of summertime along with deserts in Africa, Death Valleys Badwater Basin is the point of the lowest elevation in North America, at 282 feet below sea level. This point is 84.6 miles east-southeast of Mount Whitney, Death Valleys Furnace Creek holds the record for the highest reliably recorded air temperature in the world,134 °F on July 10,1913. This has been contested by other weather experts and it is located mostly in Inyo County, California. It has an area of about 3,000 sq mi, the highest point in Death Valley itself is Telescope Peak in the Panamint Range, which has an elevation of 11,043 feet. Death Valley is one of the best geological examples of a basin and it lies at the southern end of a geological trough known as Walker Lane, which runs north into Oregon. The valley is bisected by a right lateral slip fault system, represented by the Death Valley Fault. The eastern end of the left lateral Garlock Fault intersects the Death Valley Fault, Furnace Creek and the Amargosa River flow through the valley but eventually disappear into the sands of the valley floor. Death Valley also contains salt pans, according to current geological consensus, at various times during the middle of the Pleistocene era, inland lakes formed in Death Valley. Lake Manly received water overflowing from a chain of other Pleistocene lakes, Death Valley has a subtropical, hot desert climate, with long, extremely hot summers and short, warm or mild winters, as well as little rainfall. As a general rule, lower altitudes tend to have higher temperatures, when the sun heats the ground, that heat is then radiated upward, but the dense below-sea-level air absorbs some of this radiation and radiates some of it back towards the ground. In addition, the valley walls trap rising hot air and recycle it back down to the valley floor. This process is important in Death Valley, as it provides its specific climate. The valley is surrounded by mountains, while its surface is flat and devoid of plants, so much of the suns heat can reach the ground, absorbed by soil. When air at ground level is heated, it begins to rise, moving up past steep, high mountain ranges, which then cools slightly, sinking back down towards the valley more compressed. This air is reheated by the sun to a higher temperature, moving up the mountain again, whereby the air moves up and down in a circular motion in cycles. This heated air increases ground temperature markedly, forming the hot wind currents that are trapped by atmospheric pressure and mountains, Death Valley holds temperature records because it has an unusually high number of factors that lead to high atmospheric temperatures. The depth and shape of Death Valley influence its summer temperatures, the valley is a long, narrow basin 282 feet below sea level, yet is walled by high, steep mountain ranges
2.
Inyo County, California
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Inyo County is a county in the U. S. state of California. As of the 2010 census, the population was 18,546, Inyo County is on the east side of the Sierra Nevada and southeast of Yosemite National Park in Central California. It contains the Owens River Valley, it is flanked to the west by the Sierra Mountains and to the east by the White Mountains, Mount Whitney, the highest peak in the Contiguous United States, is on Inyo Countys western border. The Badwater Basin in Death Valley National Park, the lowest place in North America, is in eastern Inyo County. The two points are not visible from other, but both can be observed from the Panamint Range on the west side of Death Valley, above the Panamint Valley. It has the biggest elevation difference of all of the counties, with an area of 10,192 square miles, Inyo County is the second-largest county by area in California, after San Bernardino County. Almost one-half of that area is within Death Valley National Park, however, with a population density of 1.8 people per square mile, it has the lowest population density of any county in California. Present day Inyo county has been the homeland for thousands of years of the Mono tribe, Coso people, Timbisha. They spoke the Timbisha language and the Mono language with Mono traditional narratives, the descendants of these ancestors continue to live in their traditional homelands in the Owens River Valley and in Death Valley National Park. Inyo County was formed in 1866 from the territory of the unorganized Coso County created on April 4,1864 from parts of Mono and it acquired more territory from Mono County in 1870 and Kern County and San Bernardino County in 1872. For many years it has been believed that the county derived its name from the Mono tribe of Native Americans name for the mountains in its former homeland. The local Paiutes responded that that was the land of Inyo and they meant by this that those lands belonged to the Shoshone tribe headed by a man whose name was Inyo. Indian George, a fixture of many of the stories of early Death Valley days, was Inyos son, in order to provide water needs for the growing City of Los Angeles, water was diverted from the Owens River into the Los Angeles Aqueduct in 1913. The Owens River Valley cultures and environments changed substantially, from the 1910s to 1930s the Los Angeles Department of Water and Power purchased much of the valley for water rights and control. In 1941 the Los Angeles Department of Water and Power extended the Los Angeles Aqueduct system further upriver into the Mono Basin, Inyo County is host to a number of natural superlatives. Among them are, Mount Whitney, with an elevation of 14,505 feet, is the highest point in the contiguous United States, the 12th highest peak in the U. S. and the 24th highest peak in North America. S. Census Bureau, the county has an area of 10,227 square miles. It is the second-largest county by area in California and the ninth-largest in the United States, Death Valley National Park Inyo National Forest Manzanar National Historic Site There are 22 official wilderness areas in Inyo County that are part of the National Wilderness Preservation System
3.
Geographic coordinate system
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A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position. A common choice of coordinates is latitude, longitude and elevation, to specify a location on a two-dimensional map requires a map projection. The invention of a coordinate system is generally credited to Eratosthenes of Cyrene. Ptolemy credited him with the adoption of longitude and latitude. Ptolemys 2nd-century Geography used the prime meridian but measured latitude from the equator instead. Mathematical cartography resumed in Europe following Maximus Planudes recovery of Ptolemys text a little before 1300, in 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, the Dominican Republic voted against the motion, while France and Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911, the latitude of a point on Earths surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the equator, the north pole is 90° N, the south pole is 90° S. The 0° parallel of latitude is designated the equator, the plane of all geographic coordinate systems. The equator divides the globe into Northern and Southern Hemispheres, the longitude of a point on Earths surface is the angle east or west of a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses, which converge at the north and south poles, the prime meridian determines the proper Eastern and Western Hemispheres, although maps often divide these hemispheres further west in order to keep the Old World on a single side. The antipodal meridian of Greenwich is both 180°W and 180°E, the combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a graticule, the origin/zero point of this system is located in the Gulf of Guinea about 625 km south of Tema, Ghana. To completely specify a location of a feature on, in, or above Earth. Earth is not a sphere, but a shape approximating a biaxial ellipsoid. It is nearly spherical, but has an equatorial bulge making the radius at the equator about 0. 3% larger than the radius measured through the poles, the shorter axis approximately coincides with the axis of rotation
4.
Body of water
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A body of water or waterbody is any significant accumulation of water, generally on a planets surface. The term most often refers to oceans, seas, and lakes, a body of water does not have to be still or contained, Rivers, streams, canals, and other geographical features where water moves from one place to another are also considered bodies of water. Most are naturally occurring geographical features, but some are artificial, there are types that can be either. For example, most reservoirs are created by engineering dams, similarly, most harbors are naturally occurring bays, but some harbors have been created through construction. Bodies of water that are navigable are known as waterways, some bodies of water collect and move water, such as rivers and streams, and others primarily hold water, such as lakes and oceans. The term body of water can also refer to a reservoir of water held by a plant, note that there are some geographical features involving water that are not bodies of water, for example waterfalls, geysers and rapids. Arm of the sea - also sea arm, used to describe a sea loch, arroyo - a usually dry creek bed or gulch that temporarily fills with water after a heavy rain, or seasonally. Artificial lake or artificial pond - see reservoir or impoundment, barachois - a lagoon separated from the ocean by a sand bar. Bay - an area of water bordered by land on three sides, similar to, but smaller than a gulf, bayou - a slow-moving stream or a marshy lake. Bight - a large and often only slightly receding bay, or a bend in any geographical feature, billabong - see Oxbow lake, a pond or still body of water created when a river changes course and some water becomes trapped. Boil - see Seep Brook - a small stream, canal - an artificial waterway, usually connected to existing lakes, rivers, or oceans. Channel - the physical confine of a river, slough or ocean consisting of a bed. See also stream bed and strait, earth scientists generally use the term to describe a circular or round inlet with a narrow entrance, though colloquially the term is sometimes used to describe any sheltered bay. Basin - a region of land where water from rain or snowmelt drains downhill into another body of water, such as a river, lake, creek - an inlet of the sea, narrower than a cove. Delta - the location where a river flows into an ocean, sea, estuary, lake, distributary or distributary channel - a stream that branches off and flows away from a main stream channel. Draw - a usually dry creek bed or gulch that temporarily fills with water after a heavy rain, fjord - a submergent landform which has occurred due to glacial activity. Glacier - a large collection of ice or a river that moves slowly down a mountain. Glacial Pothole - see Kettle Gulf - a part of a lake or ocean that extends so that it is surrounded by land on three sides, similar to, but larger than a bay, headland - an area of water bordered by land on three sides
5.
Endorheic basin
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Such a basin may also be referred to as a closed or terminal basin or as an internal drainage system. However, in a basin, rain that falls within it does not flow out but may only leave the drainage system by evaporation. The bottom of such a basin is occupied by a salt lake or salt pan. Endorheic regions, in contrast to regions which flow to the ocean in geologically defined patterns, are closed hydrologic systems. Their surface waters drain to inland terminal locations where the water evaporates or seeps into the ground, endorheic water bodies include some of the largest lakes in the world, such as the Aral Sea and the Caspian Sea, the worlds largest saline inland sea. Most endorheic basins are arid, although there are notable exceptions, such as the Valley of Mexico, the Lake Tahoe region. Endorheic basins can be massively and rapidly affected by change and excessive water removal. An exorheic lake naturally remains at a level, so water flow into the lake may be many times more than is needed to maintain its present size. In contrast, an endorheic basin does not have enough inflow that it overflows to the ocean, endorheic lakes are bodies of water that do not flow into the sea. Most of the water falling on Earth finds its way to the oceans through a network of rivers, lakes, however, there is a class of water bodies that are located in closed or endorheic watersheds where the topography prevents their drainage to the oceans. These endorheic watersheds are often called terminal lakes or sink lakes, endorheic lakes are usually in the interior of a landmass, far from an ocean in areas of relatively low rainfall. Their watersheds are often confined by natural geologic land formations such as a mountain range, the inland water flows into dry watersheds where the water evaporates, leaving a high concentration of minerals and other inflow erosion products. Over time this input of erosion products can cause the lake to become relatively saline. Endorheic regions can occur in any climate but are most commonly found in desert locations, the Black Sea was likely such a lake, having once been an independent hydrological system before the Mediterranean Sea broke through the terrain separating the two. Lake Bonneville was another such lake, overflowing its basin in the Bonneville flood, malheur/Harney Lake in Oregon is normally cut off from drainage to the ocean, but has an outflow channel to the Malheur River that is normally dry, but flows in years of peak precipitation. Examples of relatively humid regions in endorheic basins often exist at high elevation and these regions tend to be marshy and are subject to substantial flooding in wet years. The area containing Mexico City is one case, with annual precipitation of 850 mm. Endorheic regions tend to be far inland with their boundaries defined by mountains or other features that block their access to oceans
6.
Inflow (hydrology)
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In hydrology, the inflow of a body of water is the source of the water in the body of water. It can also refer to the volume of incoming water in unit time. All bodies of water have multiple inflows, but often, one inflow may predominate, however, in many cases, no single inflow will predominate and there will be multiple primary inflows. For a lake, the inflow may be a river or stream that flows into the lake. Inflow may also be, strictly speaking, not flows, but rather precipitation, inflow can also be used to refer to groundwater recharge. The dictionary definition of inflow at Wiktionary
7.
Amargosa River
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The Amargosa River is an intermittent waterway,185 miles long, in southern Nevada and eastern California in the United States. It drains a high desert region, the Amargosa Valley in the Amargosa Desert northwest of Las Vegas, into the Mojave Desert, and finally into Death Valley where it disappears into the ground aquifer. Except for a portion of its route in the Amargosa Canyon in California and a small portion at Beatty, Nevada. A 26-mile stretch of the river between Shoshone and Dumont Dunes is protected as a National Wild and Scenic River, at the south end of Tecopa Valley the Amargosa River Natural Area protects the habitat. Except during flash floods that occur after cloudbursts, most of the course of the Amargosa River is dry on the surface, the flow is generally underground except for stretches near Beatty and near Tecopa, California, in the Amargosa Canyon. In the canyon, the passes through the Amargosa River Natural Area. The river arises at about 1,200 feet above sea level in Nye County, Nevada, thirsty Canyon Wash enters at the rivers source, and when carrying water, the river flows from there southwest into Oasis Valley. Running parallel to U. S. Route 95 near the Bullfrog Hills to the west, another 3 miles or so downstream, the river flows through Beatty and turns south-southeast through the Amargosa Narrows into the Amargosa Desert. At this point, Bare Mountain lies to the left and the Grapevine, downstream of the Narrows, still flowing roughly parallel to Route 95, the river passes Big Dune, which is on the rivers left. Shortly thereafter it passes the town of Amargosa Valley on the left, leaves Nevada, in this stretch, it receives Forty Mile Wash from the left. Running roughly parallel to California Route 127, the passes through Death Valley Junction. Shortly thereafter it receives Carson Slough, which drains Ash Meadows National Wildlife Refuge, soon the river passes between the Resting Spring Range to the left and the Greenwater Range to the right before reaching Shoshone. Below Shoshone, the continues roughly parallel to Route 127 to Tecopa. Turning west, the river crosses under Route 127 and enters Death Valley National Park between the end of the Amargosa Range on the right and the Avawatz Mountains on the left. In this stretch, the river runs parallel to Harry Wade Road and, further north, to California Route 178. The river receives Willow Creek from the right and ends in Badwater Basin, about 279 feet below sea level, disappearing into the ground, it feeds the aquifer that is the remnant of prehistoric Lake Manly. The United States Geological Survey monitors the flow of the Amargosa River at a station near the Old Spanish Trail Road,0.2 miles west of Tecopa. The average flow of the river at this station is 3.80 cubic feet per second and this is from a drainage area of 3,090 square miles, much of which is noncontributing and all of which represents about 60 percent of the total Amargosa River drainage basin
8.
Discharge (hydrology)
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In hydrology, discharge is the volume rate of water flow that is transported through a given cross-sectional area. It includes any suspended solids, dissolved chemicals, or biologic material in addition to the water itself, GH Dury and MJ Bradshaw are two hydrologists who devised the models showing the relationship between discharge and other variables in a river. The units that are used to express discharge include m³/s, ft³/s and/or acre-feet per day. For example, the discharge of the Rhine river in Europe is 2,200 cubic metres per second or 190,000,000 cubic metres per day. A commonly applied methodology for measuring, and estimating, the discharge of a river is based on a form of the continuity equation. In storm hydrology, an important consideration is the streams discharge hydrograph, the stream rises to a peak flow after each precipitation event, then falls in a slow recession. Because the peak flow also corresponds to the water level reached during the event. The amount of precipitation correlates to the volume of water that flows out of the river. The relationship between the discharge in the stream at a given cross-section and the level of the stream is described by a rating curve, average velocities and the cross-sectional area of the stream are measured for a given stream level. The velocity and the give the discharge for that level. After measurements are made for different levels, a rating table or rating curve may be developed. Once rated, the discharge in the stream may be determined by measuring the level, if a continuous level-recording device is located at a rated cross-section, the streams discharge may be continuously determined. Larger flows can transport more sediment and larger particles downstream than smaller flows due to their greater force, larger flows can also erode stream banks and damage public infrastructure
9.
Evaporation
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Evaporation is a type of vaporization of a liquid that occurs from the surface of a liquid into a gaseous phase that is not saturated with the evaporating substance. The other type of vaporization is boiling, which is characterized by bubbles of saturated vapor forming in the liquid phase, steam produced in a boiler is another example of evaporation occurring in a saturated vapor phase. Evaporation that occurs directly from the solid phase below the melting point, on average, a fraction of the molecules in a glass of water have enough heat energy to escape from the liquid. The water in the glass will be cooled by the evaporation until an equilibrium is reached where the air supplies the amount of heat removed by the evaporating water, in an enclosed environment the water would evaporate until the air is saturated. With sufficient temperature, the liquid would turn into vapor quickly, when the molecules collide, they transfer energy to each other in varying degrees, based on how they collide. Sometimes the transfer is so one-sided for a molecule near the surface that it ends up with energy to escape. Evaporation is an part of the water cycle. The sun drives evaporation of water from oceans, lakes, moisture in the soil, in hydrology, evaporation and transpiration are collectively termed evapotranspiration. Evaporation of water occurs when the surface of the liquid is exposed, allowing molecules to escape and form water vapor, when only a small proportion of the molecules meet these criteria, the rate of evaporation is low. Since the kinetic energy of a molecule is proportional to its temperature, as the faster-moving molecules escape, the remaining molecules have lower average kinetic energy, and the temperature of the liquid decreases. This phenomenon is also called evaporative cooling and this is why evaporating sweat cools the human body. Evaporation also tends to proceed quickly with higher flow rates between the gaseous and liquid phase and in liquids with higher vapor pressure. For example, laundry on a line will dry more rapidly on a windy day than on a still day. Three key parts to evaporation are heat, atmospheric pressure, on a molecular level, there is no strict boundary between the liquid state and the vapor state. Instead, there is a Knudsen layer, where the phase is undetermined, because this layer is only a few molecules thick, at a macroscopic scale a clear phase transition interface cannot be seen. It is just that the process is slower and thus significantly less visible. If evaporation takes place in an area, the escaping molecules accumulate as a vapor above the liquid. Many of the return to the liquid, with returning molecules becoming more frequent as the density
10.
Drainage basin
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A drainage basin or catchment area is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. Drainage basins connect into other drainage basins at elevations in a hierarchical pattern, with smaller sub-drainage basins. Other terms used to describe drainage basins are catchment, catchment basin, drainage area, river basin and water basin. In closed drainage basins the water converges to a point inside the basin, known as a sink, which may be a permanent lake. The drainage basin acts as a funnel by collecting all the water within the covered by the basin. Each drainage basin is separated topographically from adjacent basins by a perimeter, drainage basins are similar but not identical to hydrologic units, which are drainage areas delineated so as to nest into a multi-level hierarchical drainage system. Hydrologic units are defined to allow multiple inlets, outlets, or sinks, in a strict sense, all drainage basins are hydrologic units but not all hydrologic units are drainage basins. Drainage basins of the oceans and seas of the world. Grey areas are endorheic basins that do not drain to the oceans, the following is a list of the major ocean basins, About 48. 7% of the worlds land drains to the Atlantic Ocean. The two major mediterranean seas of the world also flow to the Atlantic, The Caribbean Sea and Gulf of Mexico basin includes most of the U. S. The Mediterranean Sea basin includes much of North Africa, east-central Africa, Southern, Central, and Eastern Europe, Turkey, and the areas of Israel, Lebanon. Just over 13% of the land in the world drains to the Pacific Ocean, the Indian Oceans drainage basin also comprises about 13% of Earths land. It drains the eastern coast of Africa, the coasts of the Red Sea and the Persian Gulf, the Indian subcontinent, Burma, antarctica comprises approximately eight percent of the Earths land. The five largest river basins, from largest to smallest, are the basins of the Amazon, the Río de la Plata, the Congo, the Nile, and the Mississippi. The three rivers that drain the most water, from most to least, are the Amazon, Ganga, endorheic drainage basins are inland basins that do not drain to an ocean. Around 18% of all land drains to endorheic lakes or seas or sinks, the largest of these consists of much of the interior of Asia, which drains into the Caspian Sea, the Aral Sea, and numerous smaller lakes. Some of these, such as the Great Basin, are not single drainage basins but collections of separate, in endorheic bodies of standing water where evaporation is the primary means of water loss, the water is typically more saline than the oceans. An extreme example of this is the Dead Sea, drainage basins have been historically important for determining territorial boundaries, particularly in regions where trade by water has been important
11.
Death Valley National Park
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Death Valley National Park is a national park in the United States. Straddling the border of California and Nevada, located east of the Sierra Nevada, the park protects the northwest corner of the Mojave Desert and contains a diverse desert environment of salt-flats, sand dunes, badlands, valleys, canyons, and mountains. It is the largest national park in the lower 48 states and has declared an International Biosphere Reserve. Approximately 91% of the park is a wilderness area. It is the hottest, driest and lowest of the parks in the United States. The second-lowest point in the Western Hemisphere is in Badwater Basin, the park is home to many species of plants and animals that have adapted to this harsh desert environment. Some examples include creosote bush, bighorn sheep, coyote, and the Death Valley pupfish, several short-lived boom towns sprang up during the late 19th and early 20th centuries to mine gold and silver. The only long-term profitable ore to be mined was borax, which was transported out of the valley with twenty-mule teams, the valley later became the subject of books, radio programs, television series, and movies. Tourism blossomed in the 1920s, when resorts were built around Stovepipe Wells, Death Valley National Monument was declared in 1933 and the park was substantially expanded and became a national park in 1994. The natural environment of the area has been shaped largely by its geology, the valley itself is actually a graben. The oldest rocks are metamorphosed and at least 1.7 billion years old. Ancient, warm, shallow seas deposited marine sediments until rifting opened the Pacific Ocean, additional sedimentation occurred until a subduction zone formed off the coast. This uplifted the region out of the sea and created a line of volcanoes, later the crust started to pull apart, creating the current Basin and Range landform. Valleys filled with sediment and, during the wet times of glacial periods, with lakes, in 2013, Death Valley National Park was designated as a dark sky park by the International Dark-Sky Association. There are two valleys in the park, Death Valley and Panamint Valley. Both of these valleys were formed within the last few million years, the result of this shearing action is additional extension in the central part of Death Valley which causes a slight widening and more subsidence there. Uplift of surrounding mountain ranges and subsidence of the floor are both occurring. The uplift on the Black Mountains is so fast that the fans there are small
12.
North America
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North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be considered a subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. North America covers an area of about 24,709,000 square kilometers, about 16. 5% of the land area. North America is the third largest continent by area, following Asia and Africa, and the fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7. 5% of the worlds population, North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge. The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago, the Classic stage spans roughly the 6th to 13th centuries. The Pre-Columbian era ended with the migrations and the arrival of European settlers during the Age of Discovery. Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists, indigenous peoples, African slaves and their descendants, European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south. Because of the history of colonialism, most North Americans speak English, Spanish or French, the Americas are usually accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass previously unknown by Europeans. In 1507, Waldseemüller produced a map, in which he placed the word America on the continent of South America. He explained the rationale for the name in the accompanying book Cosmographiae Introductio, for Waldseemüller, no one should object to the naming of the land after its discoverer. He used the Latinized version of Vespuccis name, but in its feminine form America, following the examples of Europa, Asia and Africa. Later, other mapmakers extended the name America to the continent, In 1538. Some argue that the convention is to use the surname for naming discoveries except in the case of royalty, a minutely explored belief that has been advanced is that America was named for a Spanish sailor bearing the ancient Visigothic name of Amairick. Another is that the name is rooted in a Native American language, the term North America maintains various definitions in accordance with location and context. In Canadian English, North America may be used to refer to the United States, alternatively, usage sometimes includes Greenland and Mexico, as well as offshore islands
13.
Sea level
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Mean sea level is an average level of the surface of one or more of Earths oceans from which heights such as elevations may be measured. A common and relatively straightforward mean sea-level standard is the midpoint between a low and mean high tide at a particular location. Sea levels can be affected by factors and are known to have varied greatly over geological time scales. The careful measurement of variations in MSL can offer insights into ongoing climate change, the term above sea level generally refers to above mean sea level. Precise determination of a sea level is a difficult problem because of the many factors that affect sea level. Sea level varies quite a lot on several scales of time and this is because the sea is in constant motion, affected by the tides, wind, atmospheric pressure, local gravitational differences, temperature, salinity and so forth. The easiest way this may be calculated is by selecting a location and calculating the mean sea level at that point, for example, a period of 19 years of hourly level observations may be averaged and used to determine the mean sea level at some measurement point. One measures the values of MSL in respect to the land, hence a change in MSL can result from a real change in sea level, or from a change in the height of the land on which the tide gauge operates. In the UK, the Ordnance Datum is the sea level measured at Newlyn in Cornwall between 1915 and 1921. Prior to 1921, the datum was MSL at the Victoria Dock, in Hong Kong, mPD is a surveying term meaning metres above Principal Datum and refers to height of 1. 230m below the average sea level. In France, the Marégraphe in Marseilles measures continuously the sea level since 1883 and it is used for a part of continental Europe and main part of Africa as official sea level. Elsewhere in Europe vertical elevation references are made to the Amsterdam Peil elevation, satellite altimeters have been making precise measurements of sea level since the launch of TOPEX/Poseidon in 1992. A joint mission of NASA and CNES, TOPEX/Poseidon was followed by Jason-1 in 2001, height above mean sea level is the elevation or altitude of an object, relative to the average sea level datum. It is also used in aviation, where some heights are recorded and reported with respect to sea level, and in the atmospheric sciences. An alternative is to base height measurements on an ellipsoid of the entire Earth, in aviation, the ellipsoid known as World Geodetic System 84 is increasingly used to define heights, however, differences up to 100 metres exist between this ellipsoid height and mean tidal height. The alternative is to use a vertical datum such as NAVD88. When referring to geographic features such as mountains on a topographic map, the elevation of a mountain denotes the highest point or summit and is typically illustrated as a small circle on a topographic map with the AMSL height shown in metres, feet or both. In the rare case that a location is below sea level, for one such case, see Amsterdam Airport Schiphol
14.
Mount Whitney
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Mount Whitney is the highest summit in the contiguous United States and the Sierra Nevada, with an elevation of 14,505 feet. The west slope of the mountain is in Sequoia National Park, the east slope is in the Inyo National Forest in Inyo County. The summit of Whitney is on the Sierra Crest and the Great Basin Divide and it lies near many of the highest peaks of the Sierra Nevada. The peak rises dramatically above the Owens Valley, sitting 10,778 feet or just over two miles above the town of Lone Pine 15 miles to the east, in the Owens Valley. It rises more gradually on the west side, lying only about 3,000 feet above the John Muir Trail at Guitar Lake, the mountain is partially dome-shaped, with its famously jagged ridges extending to the sides. Mount Whitney is above the line and has an alpine climate. Very few plants grow near the summit, one example is the Skypilot, the only animals are transient, such as the butterfly Parnassius phoebus and the gray-crowned rosy finch. The mountain is the highest point on the Great Basin Divide, waterways on the west side of the peak flow into Whitney Creek, which flows into the Kern River. The Kern River terminates in the Tulare Basin, during very wet years, water overflows from the Tulare Basin into the San Joaquin River which flows to the Pacific Ocean. From the east, water from Mount Whitney flows to Lone Pine Creek, which joins the Owens River, which in turn terminates at Owens Lake, the estimated elevation of the summit of Mount Whitney has changed over the years. The technology of elevation measurement has become refined and, more importantly. The peak was commonly said to be at 14,494 ft, an older plaque on the summit reads elevation 14,496.811 feet but this was estimated using the older vertical datum from 1929. Since then the shape of the Earth has been estimated more accurately, using a new vertical datum established in 1988 the benchmark is now estimated to be at 14,505 ft. The rise is caused by a fault system that runs along the eastern base of the Sierra. Thus, the granite that forms Mount Whitney is the same as the granite that forms the Alabama Hills, the raising of Whitney is due to the same geological forces that cause the Basin and Range Province, the crust of much of the intermontane west is slowly being stretched. The granite that forms Mount Whitney is part of the Sierra Nevada batholith, in Cretaceous time, masses of molten rock that originated from subduction rose underneath what is now Whitney and solidified underground to form large expanses of granite. In July 1864, the members of the California Geological Survey named the peak after Josiah Whitney, during the same expedition, geologist Clarence King attempted to climb Whitney from its west side, but stopped just short. In 1871, King returned to climb what he believed to be Whitney, upon learning of his mistake in 1873, King finally completed his own first ascent of Whitney, but did so a month too late to claim the first recorded ascent
15.
Contiguous United States
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The contiguous United States consists of the 48 adjoining U. S. states plus Washington, D. C. on the continent of North America. S. The greatest distance entirely within the 48 contiguous states is 2,802 miles, the greatest north-south line is 1,650 miles. Together, the 48 contiguous states and Washington, D. C. occupy an area of 3,119,884.69 square miles. Of this area,2,959,064.44 square miles is land, composing 83. 65% of U. S. land area, officially,160,820.25 square miles is water area, composing 62. 66% of the nations total water area. The contiguous United States would be placed 5th in the list of states and dependencies by area. The 2010 census population of area was 306,675,006, comprising 99. 33% of the nations population. While conterminous U. S. has the meaning of contiguous U. S. other terms commonly used to describe the 48 contiguous states have a greater degree of ambiguity. The term was in use prior to the admission of Alaska and Hawaii as states of the United States, the District of Columbia is not always specifically mentioned as being part of CONUS. OCONUS is derived from CONUS with O for outside added, thus referring to Outside of Continental United States, the term Lower 48 is also used to refer to the conterminous United States. The National Geographic style guide recommends the use of contiguous or conterminous United States instead of lower 48 when the 48 states are meant, both Alaskans and Hawaiians have unique labels for the contiguous United States because of their own locations relative to them. Alaska became the 49th state of the United States on January 3,1959, Alaska is on the northwest end of the North American continent, but separated from the rest of the United States Pacific coast by the Canadian province of British Columbia. In Alaska, given the ambiguity surrounding the usage of continental, several other terms have been used over the years. Hawaii became the 50th state of the United States on August 21,1959 and it is the southernmost and so far, the latest state to join the Union. Not part of any continent, Hawaii is located in the Pacific Ocean, about 2,200 miles from North America, in Hawaii and overseas American territories, for instance, the terms the Mainland or U. S. Mainland are often used to refer to the continental United States, apart from off-shore US islands, a few continental portions of the contiguous US are accessible by road only by traveling through Canada. Point Roberts, Washington, Elm Point, Minnesota, and the Northwest Angle in Minnesota are three such places, alburgh, Vermont, is not directly connected by land, but is accessible by road via bridges from within Vermont and from from New York. The 48 contiguous United States are, Washington, D. C. is distinct from the state of Washington, extreme points of the United States Mainland Definition of continental Definition of contiguous Definition of coterminous and conterminous
16.
Spring (hydrology)
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A spring is any natural situation where water flows from an aquifer to the Earths surface. It is a component of the hydrosphere, a spring may be the result of karst topography where surface water has infiltrated the Earths surface, becoming part of the area groundwater. The groundwater then travels through a network of cracks and fissure—openings ranging from intergranular spaces to large caves, the water eventually emerges from below the surface, in the form of a karst spring. The forcing of the spring to the surface can be the result of an aquifer in which the recharge area of the spring water table rests at a higher elevation than that of the outlet. Spring water forced to the surface by elevated sources are artesian wells and this is possible even if the outlet is in the form of a 300-foot-deep cave. In this case the cave is used like a hose by the higher elevated area of groundwater to exit through the lower elevation opening. Non-artesian springs may simply flow from a higher elevation through the earth to a lower elevation, still other springs are the result of pressure from an underground source in the earth, in the form of volcanic activity. The result can be water at elevated temperature such as a hot spring, the action of the groundwater continually dissolves permeable bedrock such as limestone and dolomite, creating vast cave systems. The term seep refers to springs with small flow rates in which the water has filtered through permeable earth. Fracture springs, discharge from faults, joints, or fissures in the earth, tubular springs, in which the water flows from underground caverns. Spring discharge, or resurgence, is determined by the springs recharge basin, factors that affect the recharge include the size of the area in which groundwater is captured, the amount of precipitation, the size of capture points, and the size of the spring outlet. Water may leak into the system from many sources including permeable earth, sinkholes. In some cases entire creeks seemingly disappear as the water sinks into the ground via the stream bed, grand Gulf State Park in Missouri is an example of an entire creek vanishing into the groundwater system. The water emerges 9 miles away, forming some of the discharge of Mammoth Spring in Arkansas, human activity may also affect a springs discharge--withdrawal of groundwater reduces the water pressure in an aquifer, decreasing the volume of flow. Springs are often classified by the volume of the water they discharge, the largest springs are called first-magnitude, defined as springs that discharge water at a rate of at least 2800 liters or 100 cubic feet of water per second. The scale for spring flow is as follows, Minerals become dissolved in the water as it moves through the underground rocks and this may give the water flavor and even carbon dioxide bubbles, depending on the nature of the geology through which it passes. This is why spring water is bottled and sold as mineral water. Springs that contain significant amounts of minerals are sometimes called mineral springs, Springs that contain large amounts of dissolved sodium salts, mostly sodium carbonate, are called soda springs
17.
Salt
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Salt is present in vast quantities in seawater, where it is the main mineral constituent. The open ocean has about 35 grams of solids per litre, Salt is essential for life in general, and saltiness is one of the basic human tastes. The tissues of animals contain larger quantities of salt than do plant tissues, Salt is one of the oldest and most ubiquitous food seasonings, and salting is an important method of food preservation. Salt was also prized by the ancient Hebrews, the Greeks, the Romans, the Byzantines, the Hittites, Egyptians, and the Indians. Salt became an important article of trade and was transported by boat across the Mediterranean Sea, along specially built salt roads, the scarcity and universal need for salt has led nations to go to war over it and use it to raise tax revenues. Salt is used in ceremonies and has other cultural significance. Salt is processed from salt mines, or by the evaporation of seawater or mineral-rich spring water in shallow pools. Its major industrial products are caustic soda and chlorine, and is used in industrial processes including the manufacture of polyvinyl chloride, plastics, paper pulp. Of the annual production of around two hundred million tonnes of salt, only about 6% is used for human consumption. Other uses include water conditioning processes, de-icing highways, and agricultural use, edible salt is sold in forms such as sea salt and table salt which usually contains an anti-caking agent and may be iodised to prevent iodine deficiency. As well as its use in cooking and at the table, sodium is an essential nutrient for human health via its role as an electrolyte and osmotic solute. Excessive salt consumption can increase the risk of diseases, such as hypertension, in children. Such health effects of salt have long been studied, accordingly, numerous world health associations and experts in developed countries recommend reducing consumption of popular salty foods. The World Health Organization recommends that adults should consume less than 2,000 mg of sodium, humans have always tended to build communities either around sources of salt, or where they can trade for it. All through history the availability of salt has been pivotal to civilization, the word salary comes from the Latin word for salt because the Roman Legions were sometimes paid in salt. The Natron Valley was a key region that supported the Egyptian Empire to its north, because it supplied it with a kind of salt that came to be called by its name, natron. Even before this, what is now thought to have been the first city in Europe is Solnitsata, in Bulgaria, even the name Solnisata means salt works. A very ancient salt-works operation has been discovered at the Poiana Slatinei archaeological site next to a spring in Lunca, Neamț County
18.
Fauna
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Fauna is all of the animal life of any particular region or time. The corresponding term for plants is flora, flora, fauna and other forms of life such as fungi are collectively referred to as biota. Zoologists and paleontologists use fauna to refer to a collection of animals found in a specific time or place. Paleontologists sometimes refer to a sequence of stages, which is a series of rocks all containing similar fossils. Fauna comes from the Greek names Fauna, a Roman goddess of earth and fertility, the Roman god Faunus, all three words are cognates of the name of the Greek god Pan, and panis is the Greek equivalent of fauna. Fauna is also the word for a book that catalogues the animals in such a manner, the term was first used by Carl Linnaeus from Sweden in the title of his 1745 work Fauna Suecica. Cryofauna are animals that live in, or very close to, cryptofauna are the fauna that exist in protected or concealed microhabitats. Infauna are benthic organisms that live within the substratum of a body of water, especially within the bottom-most oceanic sediments. Bacteria and microalgae may also live in the interstices of bottom sediments, epifauna, also called epibenthos, are aquatic animals that live on the bottom substratum as opposed to within it, that is, the benthic fauna that live on top of the sediment surface at the seafloor. Macrofauna are benthic or soil organisms which are retained on a 0.5 mm sieve, studies in the deep sea define macrofauna as animals retained on a 0.3 mm sieve to account for the small size of many of the taxa. Megafauna are large animals of any region or time. Meiofauna are small invertebrates that live in both marine and fresh water environments. The term Meiofauna loosely defines a group of organisms by their size, larger than microfauna but smaller than macrofauna, one environment for meiofauna is between grains of damp sand. In practice these are metazoan animals that can pass unharmed through a 0.5 –1 mm mesh but will be retained by a 30–45 μm mesh, but the exact dimensions will vary from researcher to researcher. Whether an organism passes through a 1 mm mesh also depends upon whether it is alive or dead at the time of sorting, mesofauna are macroscopic soil invertebrates such as arthropods or nematodes. Mesofauna are extremely diverse, considering just the springtails, as of 1998, microfauna are microscopic or very small animals. Other terms include avifauna, which means bird fauna and piscifauna, which means fish fauna
19.
Flora
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Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animal life is fauna, Flora, fauna and other forms of life such as fungi are collectively referred to as biota. Sometimes bacteria and fungi are also referred to as flora, as in the gut flora or skin flora. The word flora comes from the Latin name of Flora, the goddess of plants, flowers, the distinction between vegetation and flora was first made by Jules Thurmann. Prior to this, the two terms were used indiscriminately, plants are grouped into floras based on region, period, special environment, or climate. Regions can be geographically distinct habitats like mountain vs. flatland, floras can mean plant life of a historic era as in fossil flora. Lastly, floras may be subdivided by special environments, Native flora, the native and indigenous flora of an area. The plants that are grown by humans. Traditionally this classification was applied to plants regarded as undesirable, many native plants previously considered weeds have been shown to be beneficial or even necessary to various ecosystems. The flora of an area or time period can be documented in a publication also known as a flora. Floras may require specialist botanical knowledge to use with any effectiveness, traditionally they are books, but some are now published on CD-ROM or websites. It is said that the Flora Sinensis by the Polish Jesuit Michał Boym was the first book that used the name Flora in this meaning, however, despite its title it covered not only plants, but also some animals of the region. A published flora often contains diagnostic keys, often these are dichotomous keys, which require the user to repeatedly examine a plant, and decide which one of two alternatives given best applies to the plant
20.
Salicornia
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Salicornia is a genus of succulent, halophyte flowering plants in the family Amaranthaceae that grow in salt marshes, on beaches, and among mangroves. Salicornia species are native to North America, Europe, South Africa, common names for the genus include glasswort, pickleweed, and marsh samphire, these common names are also used for some species not in Salicornia. The Salicornia species are annual herbs. They grow prostrate to erect, their simple or branched stems are succulent, glabrous, older stems may be somewhat woody basally. The opposite leaves are fleshy, glabrous, sessile, basally connate and decurrent, the leaf blades are reduced to small collar-like scales with narrow scarious margin. Many species are green, but their foliage turns red in autumn, all stems are terminating in spike-like apparently jointed inflorescences. Each joint consists of two minute bracts with an 3-flowered cyme tightly embedded in cavities of the main axis. The flowers are arranged in a triangle, both lateral flowers beneath the central flower, the hermaphrodite flowers are more or less radially symmetric, with a perianth of three fleshy tepals connate nearly to the apex. There are 1-2 stamens and an ovary with two stigmas, the perianth is persistent in fruit. The vertical seed is ellipsoid, with brown, membranous. Like most members of the subfamily Salicornioideae, Salicornia species use the C3 carbon fixation pathway to take in carbon dioxide from the surrounding atmosphere, the species of Salicornia are widely distributed over the Northern Hemisphere and in southern Africa, ranging from the subtropics to subarctic regions. They are absent from South America and Australia and they grow in coastal salt marshes and in inland salty habitats like shores of salt lakes. Salicornia species are halophytes and can generally tolerate immersion in salt water, Salicornia species are used as food plants by the larvae of some Lepidoptera species, including the Coleophora case-bearers C. atriplicis and C. salicorniae. The genus probably originated during the Miocene in the region between the Mediterranean basin and Central Asia, evolving from within the perennial and frost-sensitive genus Sarcocornia, the annual, strongly inbreeding and frost-tolerant Salicornia diversified during the late Pliocene to early Pleistocene. By events of intercontinental dispersals, they reached southern Africa twice, two tetraploid lineages expanded rapidly, with the ability to colonize lower belts of the saltmarshes than their diploid relatives. Inbreeding and geographical isolation led to a number of reproductive isolated species that are only weakly differentiated. The genus Salicornia was first described in 1753 by Carl Linnaeus, Salicornia europaea was selected as the type species. The taxonomic classification of this genus is difficult, determination of species seems almost impossible for non-specialists
21.
Aquatic insect
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Aquatic insects or water insects live some portion of their life cycle in the water. They feed in the ways as other insects. Some diving insects, such as predatory diving beetles, can hunt for food underwater where land-living insects cannot compete, one problem that aquatic insects must overcome is how to get oxygen while they are under water. All animals require a source of oxygen to live, insects draw air into their bodies through spiracles, holes found along the sides of the abdomen. These spiracles are connected to tracheal tubes where oxygen can be absorbed, all aquatic insects have become adapted to their environment with the specialization of these structures. Some insects have densely packed hairs around the spiracles that allow air to remain near, while keeping water away from, the trachea open through spiracles into this air film, allowing access to oxygen. The large proportion of nitrogen in the air dissolves in water slowly and maintains the gas volume, insects of this type only rarely need to replenish their supply of air. Other aquatic insects can remain under water for long due to high concentrations of hemoglobin in their hemolymph circulating freely within their body. Hemoglobin bonds strongly to oxygen molecules, the Water Dwellers INSECTS pg.142. Stanley, D. and Bedick, J. Respiration in aquatic insects, weidenfeld & Nicholson, London Insect stages - Some larvae, nymphs and adult insects that live in freshwater. A UK-based web site with photos of various insects and other microorganisms as well as biological information
22.
Salt pan (geology)
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Natural salt pans or salt flats are flat expanses of ground covered with salt and other minerals, usually shining white under the Sun. They are found in deserts, and are natural formations, a salt pan forms by evaporation of a water pool such as a lake or pond. This happens in climates where the rate of water exceeds the rate of precipitation. If the water drain into the ground, it remains on the surface until it evaporates. Over thousands of years, the minerals accumulate on the surface and these minerals reflect the Suns rays and often appear as white areas. The crust of salt can conceal a quagmire of mud that can engulf a truck, the Qattara Depression in the eastern Sahara desert contains many such traps which served as strategic barriers during World War II. The Bonneville Salt Flats in Utah, where land speed records have been set, is a well-known salt pan in the arid regions of the western United States. The Etosha pan, in the Etosha National Park in Namibia, is another prominent example of a salt pan, the Salar de Uyuni in Bolivia is the largest salt pan in the world. It contains 50%-70% of the worlds lithium reserves, dry lake Pan Sabkha Salt evaporation pond Salt lake Sink Solonchak Briere, Peter R. Playa, playa lake, sabkha, Proposed definitions for old terms. Lowenstein, Tim K. Lawrence A. Hardie, criteria for the recognition of salt-pan evaporites
23.
Extremes on Earth
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This article describes extreme locations on Earth. Entries listed in bold are Earth-wide extremes, temperatures measured directly on the ground may exceed air temperatures by 30 to 50 °C. A ground temperature of 84 °C has been recorded in Port Sudan, Sudan. A ground temperature of 93.9 °C was recorded in Furnace Creek, Death Valley, California, United States on 15 July 1972, this may be the highest natural ground surface temperature ever recorded. The theoretical maximum possible ground surface temperature has been estimated to be between 90 and 100 °C for dry, darkish soils of low thermal conductivity, the Lut Desert was also found to have the highest maximum temperature in 5 of the 7 years measured. These measurements reflect averages over a region and so are lower than the maximum point surface temperature. Satellite measurements of the temperature of Antarctica, taken between 1982 and 2013, found a coldest temperature of −93.2 °C on 10 August 2010. Although this is not comparable to an air temperature, it is believed that the air temperature at this location would have lower than the official record lowest air temperature of −89.2 °C. Ice sheets on land, but having the base below sea level, Places under ice are not considered to be on land. The Gould Coast is the southernmost point of ocean while the southernmost open sea is nearby Bay of Whales at 78°30S, United States National Climatic Data Center AWOW Top List World Top 10 Hottest Places
24.
Argentina
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Argentina, officially the Argentine Republic, is a federal republic in the southern half of South America. With a mainland area of 2,780,400 km2, Argentina is the eighth-largest country in the world, the second largest in Latin America, and the largest Spanish-speaking one. The country is subdivided into provinces and one autonomous city, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system, Argentina claims sovereignty over part of Antarctica, the Falkland Islands, and South Georgia and the South Sandwich Islands. The earliest recorded presence in the area of modern-day Argentina dates back to the Paleolithic period. The country has its roots in Spanish colonization of the region during the 16th century, Argentina rose as the successor state of the Viceroyalty of the Río de la Plata, a Spanish overseas viceroyalty founded in 1776. The country thereafter enjoyed relative peace and stability, with waves of European immigration radically reshaping its cultural. The almost-unparalleled increase in prosperity led to Argentina becoming the seventh wealthiest developed nation in the world by the early 20th century, Argentina retains its historic status as a middle power in international affairs, and is a prominent regional power in the Southern Cone and Latin America. Argentina has the second largest economy in South America, the third-largest in Latin America and is a member of the G-15 and it is the country with the second highest Human Development Index in Latin America with a rating of very high. Because of its stability, market size and growing high-tech sector, the description of the country by the word Argentina has to be found on a Venice map in 1536. In English the name Argentina probably comes from the Spanish language, however the naming itself is not Spanish, Argentina means in Italian of silver, silver coloured, probably borrowed from the Old French adjective argentine of silver > silver coloured already mentioned in the 12th century. The French word argentine is the form of argentin and derives of argent silver with the suffix -in. The Italian naming Argentina for the country implies Argentina Terra land of silver or Argentina costa coast of silver, in Italian, the adjective or the proper noun is often used in an autonomous way as a substantive and replaces it and it is said lArgentina. The name Argentina was probably first given by the Venitian and Genoese navigators, in Spanish and Portuguese, the words for silver are respectively plata and prata and of silver is said plateado and prateado. Argentina was first associated with the silver mountains legend, widespread among the first European explorers of the La Plata Basin. The first written use of the name in Spanish can be traced to La Argentina, a 1602 poem by Martín del Barco Centenera describing the region, the 1826 constitution included the first use of the name Argentine Republic in legal documents. The name Argentine Confederation was also used and was formalized in the Argentine Constitution of 1853. In 1860 a presidential decree settled the name as Argentine Republic
25.
Dry lake
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A dry lake is an ephemeral lakebed, or a remnant of an endorheic lake. Such flats consist of fine-grained sediments infused with alkali salts, alternative names for the dry lake include alkali flat, alkali sink and playa. A playa lake may cover an area, but it is never deep. Most water in it evaporates, leaving a layer of salt on the surface and these salt covered stretches are called saltpans. The surface of a dry lake is dry, hard and rough during the dry season. Dry lakes are small, round depressions in the surface of the landscape. If its basin is primarily salt, then a dry lake is called a salt pan, pan, hardpan, another dry lake type is the mudflat. Hardpan is the dry terminus of an internally drained basin in a dry climate, the Spanish word playa literally means beach. Dry lakes are known by name in some parts of Mexico. This term is used on the Llano Estacado and other parts of the Southern High Plains. In South America, the term for a dry lake is salar or salina. Pan is the used in most of South Africa. These may include the small round pans, typical of the Chrissiesmeer area, to the extensive pans of the Northern Cape province. It is also used in Australia, distinguished are salt pans and clay pans. In Arabic, a flat is called a sabkha or shott. In Central Asia, a similar cracked mud salt flat is known as a takyr, in Iran salt flats are called kavir. A playa lake is formed when water from rain or other sources, like intersection with a table, flows into a dry depression in the landscape. If the total annual evaporation rate exceeds the annual inflow
26.
Colorado River
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The Colorado River is one of the principal rivers of the Southwestern United States and northern Mexico. The 1, 450-mile-long Colorado River drains an expansive, arid watershed that encompasses parts of seven U. S. starting in the central Rocky Mountains in the U. S. After entering Mexico, the Colorado approaches the mostly dry Colorado River Delta at the tip of the Gulf of California between Baja California and Sonora. Known for its dramatic canyons, whitewater rapids, and eleven U. S. National Parks, the Colorados large flow and steep gradient are used for generating hydroelectric power, and its major dams regulate peaking power demands in much of the Intermountain West. Intensive water consumption has dried up the lower 100 miles of the river, beginning with small bands of nomadic hunter-gatherers, Native Americans have inhabited the Colorado River basin for at least 8,000 years. Most native peoples that inhabit the basin today are descended from groups that settled in the region beginning about 1,000 years ago. Europeans first entered the Colorado Basin in the 16th century, when explorers from Spain began mapping and claiming the area, early contact between Europeans and Native Americans was generally limited to the fur trade in the headwaters and sporadic trade interactions along the lower river. After most of the Colorado River basin became part of the U. S. in 1846, several expeditions charted the Colorado in the mid-19th century – one of which, led by John Wesley Powell, was the first to run the rapids of the Grand Canyon. American explorers collected valuable information that would later be used to develop the river for navigation, lesser numbers settled in the upper basin, which was the scene of major gold strikes in the 1860s and 1870s. Large engineering works began around the start of the 20th century, with guidelines established in a series of international. The U. S. federal government was the driving force behind the construction of dams and aqueducts in the river system, although many state. Most of the dams in the river basin were built between 1910 and 1970, the system keystone, Hoover Dam, was completed in 1935. The Colorado is now considered among the most controlled and litigated rivers in the world, as demands for Colorado River water continue to rise, the level of human development and control of the river continues to generate controversy. The Colorado begins at La Poudre Pass in the Southern Rocky Mountains of Colorado, after a short run south, the river turns west below Grand Lake, the largest natural lake in the state. As it flows southwest, it gains strength from many tributaries, as well as larger ones including the Blue, Eagle. In a few areas, such as the marshy Kawuneeche Valley near the headwaters, arcing northwest, the Colorado begins to cut across the eponymous Colorado Plateau, a vast area of high desert centered at the Four Corners of the southwestern United States. In Utah, the Colorado flows primarily through the slickrock country and this is one of the most inaccessible regions of the continental United States. Here, the San Juan River, carrying runoff from the slope of Colorados San Juan Mountains, joins the Colorado from the east. S
27.
Baja California
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Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northernmost and westernmost of the 32 Federal Entities of Mexico, before becoming a state in 1952, the area was known as the North Territory of Baja California. It has an area of 70,113 km2, or 3. 57% of the mass of Mexico and comprises the northern half of the Baja California Peninsula, north of the 28th parallel. The mainland portion of the state is bordered on the west by the Pacific Ocean, on the east by Sonora, the U. S. State of Arizona, and the Gulf of California and its northern limit is the U. S. state of California. The state has an population of 3,165,776 much more than the sparsely populated Baja California Sur to the south. Over 75% of the lives in the capital city, Mexicali, in Ensenada. Other important cities include San Felipe, Rosarito and Tecate, additionally, there is a large immigrant population from the United States due to its proximity to San Diego and the cheaper cost of living compared to San Diego. There is also a significant population from Central America, many immigrants moved to Baja California for a better quality of life and the number of higher paying jobs in comparison to the rest of Mexico and Latin America. Baja California is the twelfth largest state by area in Mexico and its geography ranges from beaches to forests and deserts. The backbone of the state is the Sierra de Baja California, where the Picacho del Diablo and this mountain range effectively divides the weather patterns in the state. In the northwest, the weather is semi-dry and mediterranean, in the narrow center, the weather changes to be more humid due to altitude. It is in area where a few valleys can be found, such as the Valle de Guadalupe. To the east of the range, the Sonoran Desert dominates the landscape. In the south, the weather becomes drier and gives way to the Vizcaino Desert, the state is also home to numerous islands off both of its shores. In fact, the westernmost point in Mexico, the Guadalupe Island, is part of Baja California, the Coronado, Todos Santos and Cedros Islands are also on the Pacific Shore. On the Gulf of California, the biggest island is the Angel de la Guarda, separated from the peninsula by the deep, the first people came to the peninsula at least 11,000 years ago. At that time two main groups are thought to have been present on the peninsula. In the south were the Cochimí, in the north were several groups belonging to the Yuman language family, including the Kiliwa, Paipai, Kumeyaay, Cocopa, and Quechan
28.
Pleistocene
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The Pleistocene is the geological epoch which lasted from about 2,588,000 to 11,700 years ago, spanning the worlds most recent period of repeated glaciations. The end of the Pleistocene corresponds with the end of the last glacial period, the Pleistocene is the first epoch of the Quaternary Period or sixth epoch of the Cenozoic Era. In the ICS timescale, the Pleistocene is divided into four stages or ages, all of these stages were defined in southern Europe. In addition to this subdivision, various regional subdivisions are often used. Charles Lyell introduced the term pleistocene in 1839 to describe strata in Sicily that had at least 70% of their molluscan fauna still living today and this distinguished it from the older Pliocene Epoch, which Lyell had originally thought to be the youngest fossil rock layer. The Pleistocene has been dated from 2.588 million to 11,700 years before present and it covers most of the latest period of repeated glaciation, up to and including the Younger Dryas cold spell. The end of the Younger Dryas has been dated to about 9640 BC, the IUGS has yet to approve a type section, Global Boundary Stratotype Section and Point, for the upper Pleistocene/Holocene boundary. The proposed section is the North Greenland Ice Core Project ice core 75°06 N 42°18 W, the lower boundary of the Pleistocene Series is formally defined magnetostratigraphically as the base of the Matuyama chronozone, isotopic stage 103. Above this point there are notable extinctions of the calcareous nanofossils, Discoaster pentaradiatus, the Pleistocene covers the recent period of repeated glaciations. The name Plio-Pleistocene has, in the past, been used to mean the last ice age. The revised definition of the Quaternary, by pushing back the date of the Pleistocene to 2.58 Ma. Pleistocene climate was marked by repeated glacial cycles in which continental glaciers pushed to the 40th parallel in some places and it is estimated that, at maximum glacial extent, 30% of the Earths surface was covered by ice. In addition, a zone of permafrost stretched southward from the edge of the sheet, a few hundred kilometres in North America. The mean annual temperature at the edge of the ice was −6 °C, during interglacial times, such as at present, drowned coastlines were common, mitigated by isostatic or other emergent motion of some regions. The effects of glaciation were global, antarctica was ice-bound throughout the Pleistocene as well as the preceding Pliocene. The Andes were covered in the south by the Patagonian ice cap, there were glaciers in New Zealand and Tasmania. The current decaying glaciers of Mount Kenya, Mount Kilimanjaro, glaciers existed in the mountains of Ethiopia and to the west in the Atlas mountains. In the northern hemisphere, many glaciers fused into one, the Cordilleran ice sheet covered the North American northwest, the east was covered by the Laurentide
29.
Megaannum
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A year is the orbital period of the Earth moving in its orbit around the Sun. Due to the Earths axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the globe, four seasons are recognized, spring, summer, autumn. In tropical and subtropical regions several geographical sectors do not present defined seasons, but in the seasonal tropics, a calendar year is an approximation of the number of days of the Earths orbital period as counted in a given calendar. The Gregorian, or modern, calendar, presents its calendar year to be either a common year of 365 days or a year of 366 days, as do the Julian calendars. For the Gregorian calendar the average length of the year across the complete leap cycle of 400 years is 365.2425 days. The ISO standard ISO 80000-3, Annex C, supports the symbol a to represent a year of either 365 or 366 days, in English, the abbreviations y and yr are commonly used. In astronomy, the Julian year is a unit of time, it is defined as 365.25 days of exactly 86400 seconds, totalling exactly 31557600 seconds in the Julian astronomical year. The word year is used for periods loosely associated with, but not identical to, the calendar or astronomical year, such as the seasonal year, the fiscal year. Similarly, year can mean the period of any planet, for example. The term can also be used in reference to any long period or cycle, west Saxon ġēar, Anglian ġēr continues Proto-Germanic *jǣran. Cognates are German Jahr, Old High German jār, Old Norse ár and Gothic jer, all the descendants of the Proto-Indo-European noun *yeh₁rom year, season. Cognates also descended from the same Proto-Indo-European noun are Avestan yārǝ year, Greek ὥρα year, season, period of time, Old Church Slavonic jarŭ, Latin annus is from a PIE noun *h₂et-no-, which also yielded Gothic aþn year. Both *yeh₁-ro- and *h₂et-no- are based on verbal roots expressing movement, *h₁ey- and *h₂et- respectively, the Greek word for year, ἔτος, is cognate with Latin vetus old, from the PIE word *wetos- year, also preserved in this meaning in Sanskrit vat-sa- yearling and vat-sa-ras year. Derived from Latin annus are a number of English words, such as annual, annuity, anniversary, etc. per annum means each year, anno Domini means in the year of the Lord. No astronomical year has an number of days or lunar months. Financial and scientific calculations often use a 365-day calendar to simplify daily rates, in the Julian calendar, the average length of a year is 365.25 days. In a non-leap year, there are 365 days, in a year there are 366 days
30.
Pluvial lake
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A pluvial lake is a landlocked basin which fills with rainwater during times of glaciation, when precipitation is higher. Pluvial lakes that have since evaporated and dried out may also be referred to as paleolakes, the word pluvial comes from the Latin pluvia, which means rain. Pluvial lakes represent changes in the hydrological cycle — wet cycles generate large lakes, accumulated sediments show the variation in water level. During glacial periods, times when the level is fairly high, mud sediments will settle out. At times in between glaciers, salt deposits may be present due to the climate and evaporation of lake water. Several pluvial lakes formed in what is now the southwestern United States during the glaciation of the late Pleistocene epoch, one of these was Lake Bonneville in western Utah which covered roughly 19,000 square miles. When Lake Bonneville was at its water level, it was 1,000 feet higher than the Great Salt Lake. Fresh water mollusks have been found in mud deposits from Searles Lake in California, radiocarbon dating of the youngest mud beds yield dates from 24,000 to 12,000 years ago. When warm air from arid regions meets chilled air from glaciers, it creates cloudy, cool and this type of humid climate was present during the last glacial period in North America, and causes more precipitation than evaporation. The increase in rainfall fills the basin and forms a lake. During interglacial periods, the climate becomes arid once more and causes these lakes to evaporate, Lake Bonneville Lake Eyre, Australia Lake Lahontan Lake Manix Great Salt Lake Lake Manly Proglacial lake
31.
Timeline of glaciation
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There have been five known ice ages in the Earths history, with the Earth experiencing the Quaternary Ice Age during the present time. Within ice ages, there exist periods of more severe conditions and more temperate referred to as glacial periods and interglacial periods. Based on climate proxies, paleoclimatologists study the different climate states originating from glaciation, however, this hypothesis is still controversial, though is growing in popularity among researchers as evidence in its favor has mounted. A minor series of glaciations occurred from 460 Ma to 430 Ma, there were extensive glaciations from 350 to 250 Ma. The current ice age, called the Quaternary glaciation, has more or less extensive glaciation on 40,000. Originally, the glacial and interglacial periods of the Quaternary Ice Age were named after characteristic geological features, and it is now more common for researchers to refer to the periods by their marine isotopic stage number. The marine record preserves all the past glaciations, the evidence is less complete because successive glaciations may wipe out evidence of their predecessors. Ice cores from continental ice accumulations also provide a complete record, pollen data from lakes and bogs as well as loess profiles provided important land-based correlation data. The names system has not been filled out since the technical discussion moved to using marine isotopic stage numbers. Land-based evidence works acceptably well back as far as MIS6, hence, the names system is incomplete and the land-based identifications of ice ages previous to that are somewhat conjectural. Nonetheless, land based data is useful in discussing landforms. The last glacial and interglacial periods of the Quaternary are named, from most recent to most distant, dates shown are in thousand years before present. Older periods of the Quaternary **Table data is based on Gibbard Figure 22.1, Ice cores are used to obtain a high resolution record of recent glaciation. It confirms the chronology of the marine isotopic stages, Ice core data shows that the last 400,000 years have consisted of short interglacials about as warm as the present alternated with much longer glacials substantially colder than present. Regional Glaciation of Kansas and Nebraska, work Group on Geospatial Analysis of Glaciated Environments. Pre-Wisconsin Glaciation of Central North America, Emporia KA, INQUA Commission on Glaciation, Emporia State University. Archived from the original on May 13,2008, global correlation tables for the Quaternary. Cambridge UK, Department of Geography, University of Cambridge, Gibbard, P. L. Boreham, S. Cohen, K. M
32.
Alluvial plain
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An alluvial plain is a largely flat landform created by the deposition of sediment over a long period of time by one or more rivers coming from highland regions, from which alluvial soil forms. As the highlands due to weathering and water flow, the sediment from the hills is transported to the lower plain. Various creeks will carry the water further to a river, lake, bay, as the sediments are deposited during flood conditions in the floodplain of a creek, the elevation of the floodplain will be raised. As this reduces the channel capacity, the creek will, over time, seek new, lower paths. These processes, over time, will form the plain. The NCSS glossary instead suggests flood plain
33.
River delta
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A river delta is a landform that forms from deposition of sediment carried by a river as the flow leaves its mouth and enters slower-moving or standing water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, River deltas are ecologically important as they provide coastline defense, are home to many species, and can impact drinking water supply. The tidal currents also cannot be too strong, as sediment would wash out into the body faster than the river deposits it. Of course, the river must carry enough sediment to layer into deltas over time, the rivers velocity decreases rapidly, causing it to deposit the majority, if not all, of its load. This alluvium builds up to form the river delta, when the flow enters the standing water, it is no longer confined to its channel and expands in width. This flow expansion results in a decrease in the flow velocity, as a result, sediment drops out of the flow and deposits. Over time, this single channel builds a deltaic lobe, pushing its mouth into the standing water, as the deltaic lobe advances, the gradient of the river channel becomes lower because the river channel is longer but has the same change in elevation. As the slope of the channel decreases, it becomes unstable for two reasons. First, gravity makes the flow in the most direct course down slope. If the river breaches its natural levees, it out onto a new course with a shorter route to the ocean. Second, as its slope gets lower, the amount of stress on the bed decreases, which results in deposition of sediment within the channel. This makes it easier for the river to breach its levees, often when the channel does this, some of its flow remains in the abandoned channel. When these channel-switching events occur, a mature delta develops a distributary network, another way these distributary networks form is from deposition of mouth bars. When this mid-channel bar is deposited at the mouth of a river and this results in additional deposition on the upstream end of the mouth-bar, which splits the river into two distributary channels. A good example of the result of this process is the Wax Lake Delta, in both of these cases, depositional processes force redistribution of deposition from areas of high deposition to areas of low deposition. This results in the smoothing of the shape of the delta as the channels move across its surface. Because the sediment is laid down in fashion, the shape of these deltas approximates a fan. The more often the flow changes course, the shape develops as closer to an ideal fan, the Mississippi and Ural River deltas, with their birds-feet, are examples of rivers that do not avulse often enough to form a symmetrical fan shape
34.
Salton Sea
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The Salton Sea is a shallow, saline, endorheic rift lake located directly on the San Andreas Fault, predominantly in Californias Imperial and Coachella Valleys. The lake occupies the lowest elevations of the Salton Sink in the Colorado Desert of Imperial and its surface is 235.2 ft below sea level as of Feb.5,2017. The deepest point of the sea is 5 ft higher than the lowest point of Death Valley, the sea is fed by the New, Whitewater, and Alamo Rivers, as well as agricultural runoff, drainage systems, and creeks. Over millions of years, the Colorado River has flowed into the Imperial Valley and deposited soil, building up the terrain, the cycle of filling has been about every 400–500 years and has repeated itself many times. The latest natural cycle occurred around 1600–1700 as remembered by Native Americans who talked with the first European settlers, fish traps still exist at many locations, and the Native Americans evidently moved the traps depending upon the cycle. The most recent inflow of water from the now heavily controlled Colorado River was accidentally created by the engineers of the California Development Company in 1905, in an effort to increase water flow into the area for farming, irrigation canals were dug from the Colorado River into the valley. Due to fears of silt buildup, a cut was made in the bank of the Colorado River to further increase the water flow, while it varies in dimensions and area with fluctuations in agricultural runoff and rainfall, the Salton Sea is about 15 miles by 35 miles. With an estimated area of 343 square miles or 350 square miles. The average annual inflow is less than 1,200,000 acre feet, which is enough to maintain a depth of 43 feet. The lakes salinity, about 56 grams per litre, is greater than that of the waters of the Pacific Ocean, recently, the concentration has been increasing at a rate of about 3% per year. About 4,000,000 short tons of salt are deposited in the each year. The area was part of a vast inland sea that covered a large area of Southern California. Eventually, the reached the western shore of the Gulf of California. Were it not for this barrier the entire Salton Sink along with the Imperial Valley would be submerged as the Gulf would extend as far north as Indio. A lake exists only during times it is replenished by the rivers and rainfall and these indicate that the basin was occupied intermittently as recently as a few hundred years ago. Throughout the Spanish period of Californias history, the area was referred to as the Colorado Desert after the Colorado River, in a railroad survey completed in 1855, it was called the Valley of the Ancient Lake. On several old maps from the Library of Congress, it has been found labeled Cahuilla Valley and Cabazon Valley. Salt Creek first appeared on a map in 1867 and Salton Station is on a map from 1900
35.
Erosion
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In earth science, erosion is the action of surface processes that remove soil, rock, or dissolved material from one location on the Earths crust, then transport it away to another location. Eroded sediment or solutes may be transported just a few millimetres, the rates at which such processes act control how fast a surface is eroded. Feedbacks are also possible between rates of erosion and the amount of eroded material that is carried by, for example. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, while erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the rate of erosion in the region. Excessive erosion causes both on-site and off-site problems, on-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of bodies, as well as sediment-related damage to roads. Intensive agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion, however, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, and the surface runoff which may result from rainfall, produces four types of soil erosion, splash erosion, sheet erosion, rill erosion. Splash erosion is generally seen as the first and least severe stage in the erosion process. In splash erosion, the impact of a falling raindrop creates a crater in the soil. The distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rate is greater than the rate at which water can infiltrate into the soil. If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope, sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes, generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically of the order of a few centimetres or less and this means that rills exhibit hydraulic physics very different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow
36.
San Andreas Fault
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The San Andreas Fault is a continental transform fault that extends roughly 800 miles through California. It forms the boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip. The fault was first identified in 1895 by Professor Andrew Lawson of UC Berkeley and it is often described as having been named after San Andreas Lake, a small body of water that was formed in a valley between the two plates. However, according to some of his reports from 1895 and 1908, following the 1906 San Francisco earthquake, Lawson concluded that the fault extended all the way into southern California. In 1953, geologist Thomas Dibblee astounded the scientific establishment with his conclusion that hundreds of miles of lateral movement could occur along the fault. A project called the San Andreas Fault Observatory at Depth near Parkfield, Monterey County, is drilling into the fault to improve prediction and this is the approximate location of the epicenter of the 1906 San Francisco earthquake. The fault returns onshore at Bolinas Lagoon just north of Stinson Beach in Marin County, from Fort Ross the northern segment continues overland, forming in part a linear valley through which the Gualala River flows. It goes back offshore at Point Arena, after that, it runs underwater along the coast until it nears Cape Mendocino, where it begins to bend to the west, terminating at the Mendocino Triple Junction. The central segment of the San Andreas fault runs in a direction from Parkfield to Hollister. The southern segment begins near Bombay Beach, California, box Canyon, near the Salton Sea, contains upturned strata associated with that section of the fault. The fault then runs along the base of the San Bernardino Mountains, crosses through the Cajon Pass. These mountains are a result of movement along the San Andreas Fault and are called the Transverse Range. In Palmdale, a portion of the fault is easily examined at a roadcut for the Antelope Valley Freeway, the fault continues northwest alongside the Elizabeth Lake Road to the town of Elizabeth Lake. As it passes the towns of Gorman, Tejon Pass and Frazier Park and this restraining bend is thought to be where the fault locks up in Southern California, with an earthquake-recurrence interval of roughly 140–160 years. Northwest of Frazier Park, the runs through the Carrizo Plain. The Elkhorn Scarp defines the fault trace along much of its length within the plain, the southern segment, which stretches from Parkfield in Monterey County all the way to the Salton Sea, is capable of an 8. 1-magnitude earthquake. At its closest, this fault passes about 35 miles to the northeast of Los Angeles. Such a large earthquake on this segment would kill thousands of people in Los Angeles, San Bernardino, Riverside, and surrounding areas
37.
Aquifer
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An aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials from which groundwater can be extracted using a water well. The study of flow in aquifers and the characterization of aquifers is called hydrogeology. Related terms include aquitard, which is a bed of low permeability along an aquifer, and aquiclude, if the impermeable area overlies the aquifer, pressure could cause it to become a confined aquifer. Aquifers may occur at various depths and those closer to the surface are not only more likely to be used for water supply and irrigation, but are also more likely to be topped up by the local rainfall. Many desert areas have limestone hills or mountains within them or close to them that can be exploited as groundwater resources, overexploitation can lead to the exceeding of the practical sustained yield, i. e. more water is taken out than can be replenished. The beach provides a model to help visualize an aquifer, if a hole is dug into the sand, very wet or saturated sand will be located at a shallow depth. This hole is a well, the wet sand represents an aquifer. In 2013 large freshwater aquifers were discovered under continental shelves off Australia, China, North America and they contain an estimated half a million cubic kilometers of “low salinity” water that could be economically processed into potable water. The reserves formed when ocean levels were lower and rainwater made its way into the ground in areas that were not submerged until the ice age ended 20,000 years ago. The volume is estimated to be 100x the amount of extracted from other aquifers since 1900. The above diagram indicates typical flow directions in a view of a simple confined or unconfined aquifer system. The system shows two aquifers with one aquitard between them, surrounded by the bedrock aquiclude, which is in contact with a gaining stream, the water table and unsaturated zone are also illustrated. An aquitard is a zone within the earth that restricts the flow of groundwater from one aquifer to another, an aquitard can sometimes, if completely impermeable, be called an aquiclude or aquifuge. Aquitards are composed of layers of clay or non-porous rock with low hydraulic conductivity. Groundwater can be found at every point in the Earths shallow subsurface to some degree. Saturated means the head of the water is greater than atmospheric pressure. The definition of the table is the surface where the pressure head is equal to atmospheric pressure. Unsaturated conditions occur above the table where the pressure head is negative
38.
Lake Manly
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Lake Manly is a former pluvial lake in Death Valley, California. The lake formerly covered much of Death Valley with an area of 1,600 square kilometres during the so-called Blackwelder stand. The lake received water mainly from the Amargosa River and at various points from the Mojave River, the lake and its substantial catchment favoured the spread of a number of aquatic species, the spread of some lizards, pupfish and springsnails was aided by its waters. A number of diatoms developed in the lake, which supported a substantial ecosystem. Lake Manly existed during different times in the geological past, after the drying of this lake a later lake stage occurred 35,000 -10,000 years ago during the Tioga/Wisconsin glaciation, this lake was smaller than the Blackwelder lake. During the Holocene, the disappeared, today only ephemeral lakes occur in Death Valley during strong floods. Lake Manly is one among many major lakes that formed in the Great Basin, Lake Manly collected the overflow from a number of lakes including Lake Tecopa, Mono Lake, Lake Owens, Searles Lake, Lake Panamint, Lake Mojave, Lake Dumont and Lake Manix. Not all of them existed or drained into Lake Manly simultaneously, the formation of Lake Manly was caused by decreasing temperatures and hence decreasing evaporation as well as increased precipitation during the ice ages. Other lake systems in the Great Basin expanded due to the causes as well. The lake was named in honour of William Lewis Manly, Manly in 1849 rescued white immigrants from Death Valley. The name Lake Rogers for a potential northern lake in Death Valley was derived from a compatriot of Manly, the name Lake Manly was coined in 1932, and is sometimes spelled as Manley, which is a misspelling. Other names for the lakes in Death Valley are Death Valley Pleistocene lakes and Death Valley Lake, the existence of a lake in Death Valley in the past was also considered during that time, although it was at first not universally accepted that it had been a large lake. The first evidence for it to have been a lake was described in 1924 by Levi F. Noble. Already before in 1890 did Grove Karl Gilbert assume a lake had existed in Death Valley, while the deposits were once attributed to a single lake stand, later evidence of various lake cycles going back to the Pliocene was found. The history of Lake Manly is not as well understood as that of Lake Lahontan and Lake Bonneville, more recently, the fact that Lake Manly formerly drained the area of Yucca Mountain, a proposed nuclear waste repository, has lead to renewed scientific interest. The Badwater Basin is the deepest point in North America, Death Valley started to form about 14 million years ago, and by the Pliocene it was well developed. The valley is kept deep by vertical faulting, which is faster here than anywhere else in the US, various types of rocks form the surface areas of Death Valley, some going back as far as the Precambrian. Thus, shorelines from the lake stands are often not at the same altitude in various parts of the basin
39.
Hypersaline lake
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A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride or other salts, with saline levels surpassing that of ocean water. Specific microbial and crustacean species thrive in high salinity environments that are inhospitable to most lifeforms. Some of these species enter a dormant state when desiccated, the water of hypersaline lakes has great buoyancy due to a high salt content. The most saline water body in the world is the Don Juan Pond and its volume is some 3,000 cubic meters, but is constantly changing. The Don Juan Pond has a salinity level of over 44% and its high salinity prevents the Don Juan from freezing even when temperatures are below −50 °C. There are larger water bodies, lakes in the McMurdo Dry Valleys such as Lake Vanda with salinity of over 35%. They are covered with ice in the winter, the most saline lake outside of Antarctica is Lake Assal, in Djibouti, which has a salinity of 34. 8%. Probably the best-known hypersaline lakes are the Dead Sea and the Great Salt Lake, the Dead Sea, dividing Israel and the Palestinian West Bank from Jordan, is the worlds deepest hypersaline lake and the Araruama Lagoon is the worlds largest hypersaline lake. The Great Salt Lake, located in Utah, while having three times the surface area of the Dead Sea, is shallower and experiences much greater fluctuations in level than the Dead Sea. At its lowest recorded levels, it approaches 7.7 times the salinity of ocean water, hypersaline lakes are found on every continent, especially in arid or semi-arid regions. Brine pool Halocline Halophile List of bodies of water by salinity Salt lake
40.
Death Valley pupfish
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The Death Valley pupfish, also known as Salt Creek pupfish, is found in Death Valley National Park. There are two recognized subspecies, C. s. salinus and C. s. milleri and it is endemic to two small, isolated locations and currently classified as endangered. The desert pupfish is a small, silvery colored fish with 6-9 dark bands on its sides and it has an average length of 3.7 centimetres, with a recorded maximum of 7.8 centimetres. The males turn blue during mating season, April through October. The pupfish can withstand harsh conditions that would kill other fish, water that is 4 times more saline than the ocean, hot water up to 116 °F, and cold water down to 32 °F. This species is known from two locations in Death Valley, Salt Creek at about 49 meters below sea level, and Cottonball Marsh. They are thought to be the remainders of an ecosystem of fish species that lived in Lake Manly. The Salt Creek subspecies is found at River Springs and Soda Lake. The desert pupfish has been classified as endangered by the IUCN due to its restricted distribution. Numbers of individuals at the locations are highly variable, and fluctuate with water level. Pupfish Cyprinodon - Genus Tecopa Pupfish, Cyprinodon nevadensis calidae Saratoga pupfish, Amargosa pupfish, Cyprinodon nevadensis amargosa Found in the Amargosa River northwest of Saratoga Springs. Devils Hole pupfish, Cyprinodon diabolis, critically endangered, Found in Devils Hole 37 miles east of Furnace Creek, in western Nevada. CS1 maint, Uses authors parameter Lema, S. C, the phenotypic plasticity of Death Valleys pupfish, desert fish are revealing how the environment alters development to modify body shape and behavior. Jahren, A. H. Sanford, K. L. Ground-water is the source of the Salt Creek pupfish habitat, Death Valley. CS1 maint, Uses authors parameter Media related to Cyprinodon salinus at Wikimedia Commons Cyprinodon salinus
41.
United States Geological Survey
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The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its resources. The organization has four science disciplines, concerning biology, geography, geology. The USGS is a research organization with no regulatory responsibility. The USGS is a bureau of the United States Department of the Interior, the USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, the current motto of the USGS, in use since August 1997, is science for a changing world. The agencys previous slogan, adopted on the occasion of its anniversary, was Earth Science in the Public Service. Prompted by a report from the National Academy of Sciences, the USGS was created, by a last-minute amendment and it was charged with the classification of the public lands, and examination of the geological structure, mineral resources, and products of the national domain. This task was driven by the need to inventory the vast lands added to the United States by the Louisiana Purchase in 1803, the legislation also provided that the Hayden, Powell, and Wheeler surveys be discontinued as of June 30,1879. Clarence King, the first director of USGS, assembled the new organization from disparate regional survey agencies, after a short tenure, King was succeeded in the directors chair by John Wesley Powell. Administratively, it is divided into a Headquarters unit and six Regional Units, Other specific programs include, Earthquake Hazards Program monitors earthquake activity worldwide. The National Earthquake Information Center in Golden, Colorado on the campus of the Colorado School of Mines detects the location, the USGS also runs or supports several regional monitoring networks in the United States under the umbrella of the Advanced National Seismic System. The USGS informs authorities, emergency responders, the media, and it also maintains long-term archives of earthquake data for scientific and engineering research. It also conducts and supports research on long-term seismic hazards, USGS has released the UCERF California earthquake forecast. The USGS National Geomagnetism Program monitors the magnetic field at magnetic observatories and distributes magnetometer data in real time, the USGS operates the streamgaging network for the United States, with over 7400 streamgages. Real-time streamflow data are available online, since 1962, the Astrogeology Research Program has been involved in global, lunar, and planetary exploration and mapping. USGS operates a number of related programs, notably the National Streamflow Information Program. USGS Water data is available from their National Water Information System database
42.
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
43.
Wikimedia Commons
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Wikimedia Commons is an online repository of free-use images, sound, and other media files. It is a project of the Wikimedia Foundation, the repository contains over 38 million media files. In July 2013, the number of edits on Commons reached 100,000,000, the project was proposed by Erik Möller in March 2004 and launched on September 7,2004. The expression educational is to be according to its broad meaning of providing knowledge. Wikimedia Commons itself does not allow fair use or uploads under non-free licenses, for this reason, Wikimedia Commons always hosts freely licensed media and deletes copyright violations. The default language for Commons is English, but registered users can customize their interface to use any other user interface translations. Many content pages, in particular policy pages and portals, have also translated into various languages. Files on Wikimedia Commons are categorized using MediaWikis category system, in addition, they are often collected on individual topical gallery pages. While the project was proposed to also contain free text files. In 2012, BuzzFeed described Wikimedia Commons as littered with dicks, in 2010, Wikipedia co-founder Larry Sanger reported Wikimedia Commons to the FBI for hosting sexualized images of children known as lolicon. Wales responded to the backlash from the Commons community by voluntarily relinquishing some site privileges, over time, additional functionality has been developed to interface Wikimedia Commons with the other Wikimedia projects. Specialized uploading tools and scripts such as Commonist have been created to simplify the process of uploading large numbers of files. In order to free content photos uploaded to Flickr, users can participate in a defunct collaborative external review process. The site has three mechanisms for recognizing quality works, one is known as Featured pictures, where works are nominated and other community members vote to accept or reject the nomination. This process began in November 2004, another process known as Quality images began in June 2006, and has a simpler nomination process comparable to Featured pictures. Quality images only accepts works created by Wikimedia users, whereas Featured pictures additionally accepts nominations of works by third parties such as NASA, the three mentioned processes select a slight part from the total number of files. However, Commons collects files of all quality levels, from the most professional level across simple documental, files with specific defects can be tagged for improvement and warning or even proposed for deletion but there exists no process of systematic rating of all files. The site held its inaugural Picture of the Year competition, for 2006, all images that were made a Featured picture during 2006 were eligible, and voted on by eligible Wikimedia users during two rounds of voting
