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105-664: The Antelope Valley is located in northern Los Angeles County, California , United States, and the southeast portion of California's Kern County , and constitutes the western tip of the Mojave Desert . It is situated between the Tehachapi , Sierra Pelona , and the San Gabriel Mountains . The valley was named for the pronghorns that roamed there until they were all eliminated in the 1880s, mostly by hunting, or resettled in other areas. The principal cities in

210-585: A decrease due to net migration of 361,895 people. Immigration resulted in a net increase of 293,433 people, and migration from within the United States resulted in a net decrease of 655,328 people. The racial makeup of Los Angeles County was 4,936,599 (50%) White, 1,346,865 (13.7%) Asian, 856,874 (9%) African American, 72,828 (0.7%) Native American, 26,094 (0.3%) Pacific Islander, 2,140,632 (21.8%) from other races, and 438,713 (4.5%) from two or more races. Non-Hispanic whites numbered 2,728,321, or 28% of

315-573: A harsh environment for organisms. Sediment often settles in intertidal mudflats which are extremely difficult to colonize. No points of attachment exist for algae , so vegetation based habitat is not established. Sediment can also clog feeding and respiratory structures of species, and special adaptations exist within mudflat species to cope with this problem. Lastly, dissolved oxygen variation can cause problems for life forms. Nutrient-rich sediment from human-made sources can promote primary production life cycles, perhaps leading to eventual decay removing

420-406: A large cluster of government buildings in the city's Civic Center. Historically, the courthouses were county-owned buildings that were maintained at county expense, which created significant friction since the trial court judges, as officials of the state government, had to lobby the county Board of Supervisors for facility renovations and upgrades. In turn, the state judiciary successfully persuaded

525-400: A median income of $ 36,299 versus $ 30,981 for females. The per capita income for the county was $ 20,683. There are 14.4% of families living below the poverty line and 17.9% of the population, including 24.2% of under 18 and 10.5% of those over 64. Los Angeles County has the highest number of millionaires of any county in the nation, totaling 261,081 households as of 2007. The homeownership rate

630-529: A number of coastal water bodies such as coastal lagoons and brackish seas. A more comprehensive definition of an estuary is "a semi-enclosed body of water connected to the sea as far as the tidal limit or the salt intrusion limit and receiving freshwater runoff; however the freshwater inflow may not be perennial, the connection to the sea may be closed for part of the year and tidal influence may be negligible". This broad definition also includes fjords , lagoons , river mouths , and tidal creeks . An estuary

735-622: A scientific observation of the valley in 1844. After Fremont's visit the 49ers crossed the valley via the Old Tejon Pass into the San Joaquin Valley on their way to the gold fields. Later, a better wagon road, the Stockton – Los Angeles Road route to Tejon Pass , followed in 1854. Stagecoach lines across the southern foothills came through the valley along this wagon road, and were the preferred method for travelers before

840-516: A single county. As a result, both the county superior court and the federal district court are respectively the busiest courts of their type in the nation. Many celebrities have been seen in Los Angeles courts. In 2003, the television show Extra (based in nearby Glendale ) found itself running so many reports on the legal problems of local celebrities that it spun them off into a separate show, Celebrity Justice . State cases are appealed to

945-408: A type of ecosystem in some estuaries that have been negatively impacted by eutrophication. Cordgrass vegetation dominates the salt marsh landscape. Excess nutrients allow the plants to grow at greater rates in above ground biomass, however less energy is allocated to the roots since nutrients is abundant. This leads to a lower biomass in the vegetation below ground which destabilizes the banks of

1050-563: A well-mixed water column and the disappearance of the vertical salinity gradient . The freshwater-seawater boundary is eliminated due to the intense turbulent mixing and eddy effects . The lower reaches of Delaware Bay and the Raritan River in New Jersey are examples of vertically homogeneous estuaries. Inverse estuaries occur in dry climates where evaporation greatly exceeds the inflow of freshwater. A salinity maximum zone

1155-436: A wholly marine embayment to any of the other estuary types. The most important variable characteristics of estuary water are the concentration of dissolved oxygen, salinity and sediment load. There is extreme spatial variability in salinity, with a range of near-zero at the tidal limit of tributary rivers to 3.4% at the estuary mouth. At any one point, the salinity will vary considerably over time and seasons, making it

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1260-414: A wide effect on the surrounding water bodies.  In turn, this can decrease fishing industry sales in one area and across the country. Production in 2016 from recreational and commercial fishing contributes billions of dollars to the United States' gross domestic product (GDP). A decrease in production within this industry can affect any of the 1.7 million people the fishing industry employs yearly across

1365-574: Is 365,000 workers. Despite a business exodus from Downtown Los Angeles since the COVID-19 pandemic , the city's urban core is evolving as a cultural center with the world's largest showcase of architecture designed by Frank Gehry . The following major companies have headquarters in Los Angeles County: The Los Angeles County Office of Education provides a supporting role for school districts in

1470-400: Is 47.9%, and the median value for houses is $ 409,300. 42.2% of housing units are in multi-unit structures. Los Angeles County has the largest number of homeless people , with "48,000 people living on the streets, including 6,000 veterans ," in 2010. As of 2017 the number of homeless people in the county increased to nearly 58,000. In 2015, there were over two thousand Christian churches ,

1575-455: Is a dynamic ecosystem having a connection to the open sea through which the sea water enters with the rhythm of the tides . The effects of tides on estuaries can show nonlinear effects on the movement of water which can have important impacts on the ecosystem and waterflow. The seawater entering the estuary is diluted by the fresh water flowing from rivers and streams. The pattern of dilution varies between different estuaries and depends on

1680-663: Is a state-mandated county transportation commission that also operates bus and rail. In the United States House of Representatives , Los Angeles County is split between 17 congressional districts. In the California State Senate , Los Angeles County is split between 13 legislative districts. In the California State Assembly , Los Angeles County is split between 24 legislative districts. On November 4, 2008, Los Angeles County

1785-554: Is bounded by the Garlock and San Andreas fault systems. Precipitation in the surrounding mountain ranges contributes to groundwater recharge . The Antelope Valley is home to a wide range of plants and animals. This includes hundreds of plants such as the California juniper , Joshua tree , California scrub oak , creosote , and wildflowers, notably the California poppy . Winter brings much-needed rain, which slowly penetrates

1890-513: Is derived from the Latin word aestuarium meaning tidal inlet of the sea, which in itself is derived from the term aestus , meaning tide. There have been many definitions proposed to describe an estuary. The most widely accepted definition is: "a semi-enclosed coastal body of water, which has a free connection with the open sea, and within which seawater is measurably diluted with freshwater derived from land drainage". However, this definition excludes

1995-411: Is formed, and both riverine and oceanic water flow close to the surface towards this zone. This water is pushed downward and spreads along the bottom in both the seaward and landward direction. Examples of an inverse estuary are Spencer Gulf , South Australia, Saloum River and Casamance River , Senegal. Estuary type varies dramatically depending on freshwater input, and is capable of changing from

2100-491: Is home to the largest Armenian population outside of Armenia. Los Angeles County contains the largest Iranian population outside of Iran of any other county or county equivalent globally. At the 2000 census, there were 9,519,338 people, 3,133,774 households, and 2,137,233 families in the county. The population density was 2,344 inhabitants per square mile (905/km ). There were 3,270,909 housing units at an average density of 806 units per square mile (311 units/km ). Of

2205-566: Is less restricted, and there is a slow but steady exchange of water between the estuary and the ocean. Fjord-type estuaries can be found along the coasts of Alaska , the Puget Sound region of western Washington state , British Columbia , eastern Canada, Greenland , Iceland , New Zealand, and Norway. These estuaries are formed by subsidence or land cut off from the ocean by land movement associated with faulting , volcanoes , and landslides . Inundation from eustatic sea-level rise during

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2310-747: Is located near Boron . Also, several private and home-school high schools arein the area, most notably: The Antelope Valley Symphony Orchestra is a professional ensemble that performs four concerts each year at the Lancaster Performing Arts Center. It is an auxiliary of Antelope Valley College, and performs regularly with the Antelope Valley College Civic Orchestra. Antelope Valley Indian Museum State Historic Park has been featured in films such as The Magnificent Seven Ride! (1972) and The Stone Killer (1973). Mackenna's Gold (1964)

2415-431: Is managed on a day-to-day basis by a chief executive officer and is organized into many departments, each of which is enormous in comparison to equivalent county-level (and even many state-level) departments anywhere else in the United States. Some of the larger or better-known departments include: The Los Angeles County Metropolitan Transportation Authority , despite its name, is not a County department. Technically it

2520-472: Is more arts-centered. Santa Monica's pier is a well known tourist spot, famous for its Ferris wheel and bumper car rides, which were featured in the introductory segment of the television sitcom Three's Company . Further north in Pacific Palisades one finds the beaches used in the television series Baywatch . The fabled Malibu , home of many film and television stars, lies west of it. In

2625-416: Is one of the most ethnically diverse U.S. counties. The county's seat , Los Angeles , is the second most populous city in the United States , with 3,822,238 residents estimated in 2022. The county has been world-renowned as the domicile of the U.S. motion picture industry since the latter's inception in the early 20th century. Los Angeles County is one of the original counties of California , created at

2730-771: Is over 50 miles (80 km) away. Include: On the ridgeline of the San Gabriel Mountains, the Angeles Crest Highway ( State Route 2 ) snakes 60 miles (100 km) through the Angeles National Forest to La Cañada Flintridge and the Greater Los Angeles metropolitan region. Some people of note have spent time in the valley, including: Over 10,000 population Under 10,000 population Los Angeles County, California Los Angeles County , officially

2835-399: Is rainfall mostly in the wintertime, but the mountains in the north-central part of the county have snow during winter. In 2019, the median household income in the county was $ 72,797. Los Angeles County had a population of 9,818,605 in the 2010 United States Census . This includes a natural increase since the last census of 583,364 people (i.e., 1,152,564 births minus 569,200 deaths) and

2940-511: Is the U.S. Supreme Court in Washington, D.C. The following table includes the number of incidents reported and the rate per 1,000 persons for each type of offense. Crime in 2013 According to the authors of Wild L.A. , a book about urban biodiversity, "Los Angeles is the birdiest county in the country with over 500 recorded species." L.A.'s amenable climate supports a large number of introduced, tropical and migratory species. Because of

3045-644: Is the largest diocese in the United States. In 2014, the county had 3,275 religious organizations, the most out of all US counties. The Government of Los Angeles County is defined and authorized under the California Constitution , California law and the Charter of the County of Los Angeles. Much of the Government of California is in practice the responsibility of local governments such as

3150-646: Is the whitefish species from the European Alps . Eutrophication reduced the oxygen levels in their habitats so greatly that whitefish eggs could not survive, causing local extinctions. However, some animals, such as carnivorous fish, tend to do well in nutrient-enriched environments and can benefit from eutrophication. This can be seen in populations of bass or pikes. Eutrophication can affect many marine habitats which can lead to economic consequences. The commercial fishing industry relies upon estuaries for approximately 68 percent of their catch by value because of

3255-534: The County of Los Angeles and sometimes abbreviated as L.A. County , is the most populous county in the United States , with 9,861,224 residents estimated in 2022. Its population is greater than that of 40 individual U.S. states . Comprising 88 incorporated cities and many unincorporated areas within a total area of 4,083 square miles (10,570 km ), it is home to more than a quarter of Californians and

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3360-748: The Holocene Epoch has also contributed to the formation of these estuaries. There are only a small number of tectonically produced estuaries; one example is the San Francisco Bay , which was formed by the crustal movements of the San Andreas Fault system causing the inundation of the lower reaches of the Sacramento and San Joaquin rivers . In this type of estuary, river output greatly exceeds marine input and tidal effects have minor importance. Freshwater floats on top of

3465-473: The Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea level began to rise about 10,000–12,000 years ago. Estuaries are typically classified according to their geomorphological features or to water-circulation patterns. They can have many different names, such as bays , harbors , lagoons , inlets , or sounds , although some of these water bodies do not strictly meet

3570-720: The La Brea Tar Pits , the Arboretum of Los Angeles , and two horse racetracks and two car racetracks ( Pomona Raceway and Irwindale Speedway ), also the RMS ; Queen Mary located in Long Beach, and the Long Beach Grand Prix , and miles of beaches—from Zuma to Cabrillo. Venice Beach is a popular attraction whose Muscle Beach used to attract throngs of tourists admiring "hardbodies". Today, it

3675-609: The Los Angeles Basin , San Fernando Valley , and San Gabriel Valley . Other population centers are found in the Santa Clarita Valley , Pomona Valley , Crescenta Valley and Antelope Valley . The county is divided west-to-east by the San Gabriel Mountains , which are part of the Transverse Ranges of southern California, and are contained mostly within the Angeles National Forest . Most of

3780-610: The Mandovi estuary in Goa during the monsoon period. As tidal forcing increases, river output becomes less than the marine input. Here, current induced turbulence causes mixing of the whole water column such that salinity varies more longitudinally rather than vertically, leading to a moderately stratified condition. Examples include the Chesapeake Bay and Narragansett Bay . Tidal mixing forces exceed river output, resulting in

3885-640: The Mid-Atlantic coast, and Galveston Bay and Tampa Bay along the Gulf Coast . Bar-built estuaries are found in a place where the deposition of sediment has kept pace with rising sea levels so that the estuaries are shallow and separated from the sea by sand spits or barrier islands. They are relatively common in tropical and subtropical locations. These estuaries are semi-isolated from ocean waters by barrier beaches ( barrier islands and barrier spits ). Formation of barrier beaches partially encloses

3990-618: The Philippines were the most common foreign places of birth in 2000 in Northwest Antelope Valley. Mexico and El Salvador were the most common foreign places of birth in the northwest. German and English were the most common ancestries in the northeast. German and Irish were the most common ancestries in Southeast Antelope Valley. Mexico and Colombia were the common foreign places of birth in

4095-647: The Sacramento-San Joaquin River Delta in northern California has caused and causes adverse environmental and social effects in the delta: "Over decades, [the] competing uses for water supply and habitat have jeopardized the Delta's ability to meet either need. All stakeholders agree the estuary is in trouble and requires long-term solutions to ensure reliable, quality water supplies and a healthy ecosystem." The Antelope Valley's population growth and development place considerable stress on

4200-710: The San Emigdio Mountains , the southernmost part of Tehachapi Mountains and the Sierra Pelona Mountains . Los Angeles County includes San Clemente Island and Santa Catalina Island , which are part of the Channel Islands archipelago off the Pacific Coast . The Northern part of the county has a Desert climate , while the rest of the county generally is a mix of Semi-arid and a hot-summer Mediterranean climate . There

4305-751: The San Gabriel River and the Santa Clara River flow in Los Angeles County, while the primary mountain ranges are the Santa Monica Mountains and the San Gabriel Mountains . The western extent of the Mojave Desert begins in the Antelope Valley , in the northeastern part of the county. Most of the population of Los Angeles County resides in the south and southwest, with major population centers in

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4410-734: The Severn Estuary in the United Kingdom and the Ems Dollard along the Dutch-German border. The width-to-depth ratio of these estuaries is typically large, appearing wedge-shaped (in cross-section) in the inner part and broadening and deepening seaward. Water depths rarely exceed 30 m (100 ft). Examples of this type of estuary in the U.S. are the Hudson River , Chesapeake Bay , and Delaware Bay along

4515-478: The black-tailed godwit , rely on estuaries. Two of the main challenges of estuarine life are the variability in salinity and sedimentation . Many species of fish and invertebrates have various methods to control or conform to the shifts in salt concentrations and are termed osmoconformers and osmoregulators . Many animals also burrow to avoid predation and to live in a more stable sedimental environment. However, large numbers of bacteria are found within

4620-547: The 1770s, during the colonization of North America . Father Francisco Garcés , a Spanish Franciscan friar, is believed to have traveled the west end of the valley in 1776. The Spanish established El Camino Viejo through the western part of the valley between Los Angeles and the missions of the San Francisco Bay in the 1780s. By 1808, the Spanish had moved the native people out of the valley and into missions. Jedediah Smith came through in 1827, and John C. Fremont made

4725-467: The 1870s, Los Angeles County was divided into townships (many of which were amalgamations of one or more old ranchos ): As shown by the map below, Los Angeles County is bordered on the north by Kern County , on the east by San Bernardino County , on the southeast by Orange County , on the south by the Pacific Ocean , and on the west by Ventura County . According to the U.S. Census Bureau ,

4830-496: The 3,133,774 households 37% had children under the age of 18 living with them, 48% were married couples living together, 15% had a female householder with no husband present, and 32% were non-families. 25% of households were one person and 7% were one person aged 65 or older. The average household size was 2.98 and the average family size was 3.61. The age distribution was 28% under the age of 18, 10% from 18 to 24, 33% from 25 to 44, 19% from 45 to 64, and 10% 65 or older. The median age

4935-643: The Antelope Valley are Palmdale and Lancaster . The Antelope Valley comprises the western tip of the Mojave Desert , opening up to the Victor Valley and the Great Basin to the east. Lying north of the San Gabriel Mountains , southeast of the Tehachapis , and east of the Sierra Pelona Mountains , this desert ecosystem spans around 2,200 sq mi (5,698 km). The valley

5040-528: The Antelope Valley depends mainly on pumping of groundwater from the valley's aquifers and on importing additional water from the California Aqueduct . Long-term groundwater pumping has lowered the water table , thereby increasing pumping lifts, reducing well efficiency, and causing land subsidence . While aqueducts supply additional water that meets increasing human demand for agricultural, industrial, and domestic uses, diversion of water from

5145-993: The Court of Appeal for the Second Appellate District, which is also headquartered in the Civic Center , and then to the California Supreme Court , which is headquartered in San Francisco but also hears argument in Los Angeles (again, in the Civic Center). Federal cases are appealed to the Court of Appeals for the Ninth Circuit , which hears them at its branch building in Pasadena . The court of last resort for federal cases

5250-458: The Government of Los Angeles County. The county's voters elect a governing five-member Los Angeles County Board of Supervisors . The small size of the board means each supervisor represents over 2 million people. The board operates in a legislative, executive, and quasi-judicial capacity. As a legislative authority, it can pass ordinances for the unincorporated areas (ordinances that affect

5355-695: The Greater Los Angeles Area. LAX is operated by Los Angeles World Airports (LAWA), an agency of the City of Los Angeles. Other important commercial airports in Los Angeles County include: The following general aviation airports also are located in Los Angeles County: The U.S. Air Force operates three airports in Los Angeles County: Estuary Most existing estuaries formed during

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5460-400: The United States. Estuaries are incredibly dynamic systems, where temperature, salinity, turbidity, depth and flow all change daily in response to the tides. This dynamism makes estuaries highly productive habitats, but also make it difficult for many species to survive year-round. As a result, estuaries large and small experience strong seasonal variation in their fish communities. In winter,

5565-513: The above definition of an estuary and could be fully saline. Many estuaries suffer degeneration from a variety of factors including soil erosion , deforestation , overgrazing , overfishing and the filling of wetlands. Eutrophication may lead to excessive nutrients from sewage and animal wastes; pollutants including heavy metals , polychlorinated biphenyls , radionuclides and hydrocarbons from sewage inputs; and diking or damming for flood control or water diversion. The word "estuary"

5670-402: The area's dry ground, bringing up native grasses and wildflowers. Poppy season depends completely on the precipitation, but a good bloom can be killed off by the unusual weather in the late winter and early spring. The Antelope Valley gets its name from its history of pronghorn grazing in large numbers. In 1882-85, the valley lost 30,000 head of antelope, almost half of the species for which it

5775-715: The area. The county office also operates two magnet schools, the International Polytechnic High School and Los Angeles County High School for the Arts . There are a number of private schools in the county, most notably those operated by the Roman Catholic Archdiocese . The county's public education sector is run by numerous school districts with the Los Angeles Unified School District being

5880-452: The bottom where they are harmless. Historically the oysters filtered the estuary's entire water volume of excess nutrients every three or four days. Today that process takes almost a year, and sediment, nutrients, and algae can cause problems in local waters. Some major rivers that run through deserts historically had vast, expansive estuaries that have been reduced to a fraction of their former size, because of dams and diversions. One example

5985-549: The coming of the Southern Pacific Railroad in 1876. The rail service linking the valley to the Central Valley and Los Angeles started its first large influx of white settlers, and farms and towns soon sprouted on the valley floor. The aircraft (now called aerospace) industry took hold in the valley at Plant 42 in 1952. Edwards AFB, then called Muroc Army Air Field, was established in 1933. The area

6090-437: The county are considered ecologically significant indicators of ecosystem health and may be documented using the iNaturalist app. Los Angeles County is commonly associated with the entertainment and digital media industry; all five major film studios — Paramount Pictures , Sony Pictures , Warner Bros. , Universal Pictures , and Walt Disney Studios —are located within the county. Numerous other major industries also define

6195-402: The county has an area of 4,751 square miles (12,310 km ), of which 4,058 square miles (10,510 km ) (85%) is land and 693 square miles (1,790 km ) (15%) is water. Los Angeles County borders 70 miles (110 km) of coast on the Pacific Ocean and encompasses mountain ranges, valleys, forests, islands, lakes, rivers, and desert. The Los Angeles River , Rio Hondo , Ballona Creek ,

6300-532: The county is 48.7% White, 11.0% African American, 0.8% Native American, 10.0% Asian, 0.3% Pacific Islander, 23.5% from other races, and 4.9% from two or more races. 44.6% of the population are Hispanic or Latino of any race. The largest European-American ancestry groups are German (6%), Irish (5%), English (4%) and Italian (3%). 45.9% of the population reported speaking only English at home; 37.9% spoke Spanish, 2.22% Tagalog , 2.0% Chinese, 1.9% Korean , 1.87% Armenian , 0.5% Arabic , and 0.2% Hindi . The county has

6405-475: The county's highest peaks are in the San Gabriel Mountains, including Mount San Antonio 10,068 feet (3,069 m) at the Los Angeles– San Bernardino county lines, Mount Baden-Powell 9,399 feet (2,865 m), Mount Burnham 8,997 feet (2,742 m) and Mount Wilson 5,710 feet (1,740 m). Several lower mountains are in the northern, western, and southwestern parts of the county, including

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6510-409: The county's wide range of biomes it is possible to see desert bighorn sheep and green sea turtles in the same day, without crossing the county line. The range of habitats in the county is "greater than in many states, with mountains, wetlands, desert, ocean, meadows and chaparral, each with its own endemic species." There are at least 100 species of trees, and 1000 species of non-native plants, in

6615-409: The dissolved oxygen from the water; thus hypoxic or anoxic zones can develop. Nitrogen is often the lead cause of eutrophication in estuaries in temperate zones. During a eutrophication event, biogeochemical feedback decreases the amount of available silica . These feedbacks also increase the supply of nitrogen and phosphorus, creating conditions where harmful algal blooms can persist. Given

6720-499: The early 1900s caused a scarcity in bunch grass , their main food source. Now, the sighting of a pronghorn is rare, although a small number remain in the western portion of the valley. Common game species in the Antelope Valley include mule deer and mountain quail . Other common species in the Antelope Valley include the golden-mantled ground squirrel , Beechey ground squirrel , red-tailed hawk , Cooper's hawk , Stellar's jay , leopard frog , and rattlesnake . Human water use in

6825-420: The early 1980s to around three times its former level. Major retail has followed the population influx, centered on Palmdale's Antelope Valley Mall . The Lancaster—Palmdale urbanized area is home to 372,287 people. Some long-term residents living far out in the desert have been cited by Los Angeles County's nuisance abatement teams for code violations, forcing residents to either make improvements or move. One of

6930-522: The eastern Antelope Valley – California State Parks' largest in area within the county. The California Poppy Reserve is located in the western Antelope Valley and shows off the State's flower in great quantity on its rolling hills every spring. Los Angeles International Airport (LAX), located in the Westchester district, is the primary commercial airport for commercial airlines in the county and

7035-430: The economy of Los Angeles County, including international trade supported by the Port of Los Angeles and the Port of Long Beach , music recording and production, aerospace and defense, fashion, and professional services such as law, medicine, engineering and design services, financial services. High-tech sector employment within Los Angeles County is 368,500 workers, and manufacturing employment within Los Angeles County

7140-401: The effects of modifying the estuarine circulation. Fjord -type estuaries are formed in deeply eroded valleys formed by glaciers . These U-shaped estuaries typically have steep sides, rock bottoms, and underwater sills contoured by glacial movement. The estuary is shallowest at its mouth, where terminal glacial moraines or rock bars form sills that restrict water flow. In the upper reaches of

7245-543: The estuary impacted by human activities, and over time may shift the basic composition of the ecosystem, and the reversible or irreversible changes in the abiotic and biotic parts of the systems from the bottom up. For example, Chinese and Russian industrial pollution, such as phenols and heavy metals, has devastated fish stocks in the Amur River and damaged its estuary soil. Estuaries tend to be naturally eutrophic because land runoff discharges nutrients into estuaries. With human activities, land run-off also now includes

7350-424: The estuary, the depth can exceed 300 m (1,000 ft). The width-to-depth ratio is generally small. In estuaries with very shallow sills, tidal oscillations only affect the water down to the depth of the sill, and the waters deeper than that may remain stagnant for a very long time, so there is only an occasional exchange of the deep water of the estuary with the ocean. If the sill depth is deep, water circulation

7455-720: The estuary, with only narrow inlets allowing contact with the ocean waters. Bar-built estuaries typically develop on gently sloping plains located along tectonically stable edges of continents and marginal sea coasts. They are extensive along the Atlantic and Gulf coasts of the U.S. in areas with active coastal deposition of sediments and where tidal ranges are less than 4 m (13 ft). The barrier beaches that enclose bar-built estuaries have been developed in several ways: Fjords were formed where Pleistocene glaciers deepened and widened existing river valleys so that they become U-shaped in cross-sections. At their mouths there are typically rocks, bars or sills of glacial deposits , which have

7560-609: The fish community is dominated by hardy marine residents, and in summer a variety of marine and anadromous fishes move into and out of estuaries, capitalizing on their high productivity. Estuaries provide a critical habitat to a variety of species that rely on estuaries for life-cycle completion. Pacific Herring ( Clupea pallasii ) are known to lay their eggs in estuaries and bays, surfperch give birth in estuaries, juvenile flatfish and rockfish migrate to estuaries to rear, and anadromous salmonids and lampreys use estuaries as migration corridors. Also, migratory bird populations, such as

7665-400: The great biodiversity of this ecosystem. During an algal bloom , fishermen have noticed a significant increase in the quantity of fish. A sudden increase in primary productivity causes spikes in fish populations which leads to more oxygen being utilized. It is the continued deoxygenation of the water that then causes a decline in fish populations. These effects can begin in estuaries and have

7770-420: The impacts do not end there. Plant death alters the entire food web structure which can result in the death of animals within the afflicted biome . Estuaries are hotspots for biodiversity , containing a majority of commercial fish catch, making the impacts of eutrophication that much greater within estuaries. Some specific estuarine animals feel the effects of eutrophication more strongly than others. One example

7875-475: The lake beds offer a vast landing area. Although NASA later built a landing strip at Kennedy Space Center , Edwards was retained as the backup in case of bad weather at Cape Canaveral . NASA Neil A. Armstrong Flight Research Center is a tenant organization at Edwards AFB. The center is best known for the X-15 experimental rocket ship program. It has been the home of NASA's high-performance aircraft research since it

7980-560: The largest Native American population of any county in the nation: according to the 2000 census, it has more than 153,550 people of indigenous descent, and most are from Latin America . As estimated by the Public Policy Institute of California in 2008, Los Angeles County is home to more than one-third of California's undocumented immigrants , who make up more than ten percent of the population. Los Angeles County

8085-761: The largest one running public schools primarily within the city of Los Angeles and its immediately neighboring cities. The county's most visited park is Griffith Park , owned by the city of Los Angeles. The county is also known for the annual Rose Parade in Pasadena, the annual Los Angeles County Fair in Pomona, the Los Angeles County Museum of Art , the Los Angeles Zoo , the Natural History Museum of Los Angeles County ,

8190-602: The local and regional water systems. According to David Leighton of the United States Geological Survey : "A deliberate management effort will be required to meet future water demand in the Antelope Valley without incurring significant economic and environmental costs associated with overuse of the ground-water resource." The first peoples of the Antelope Valley include the Kawaiisu , Kitanemuk , Serrano , and Tataviam . Europeans first entered in

8295-434: The majority of which are Catholic. Roman Catholic adherents number close to 40% of the population. There were 202 Jewish synagogues , 145 Buddhist temples, 38 Muslim mosques , 44 Baháʼí Faith worship centers, 37 Hindu temples , 28 Tenrikyo churches and fellowships, 16 Shinto worship centers, and 14 Sikh gurdwaras in the county. The Roman Catholic Archdiocese of Los Angeles has approximately 5 million members and

8400-551: The manufacturing and integration and testing of new military aviation equipment. With the size of the industry there, Antelope Valley has been nicknamed the Aerospace Valley. The valley's first main industry as a part of the United States was agriculture . Historically known in the region for its extensive alfalfa fields and fruit crops, farmers now are growing a wider variety of crops, such as carrots, onions, lettuce, and potatoes. As housing tracts continue to build in

8505-525: The many chemicals used as fertilizers in agriculture as well as waste from livestock and humans. Excess oxygen-depleting chemicals in the water can lead to hypoxia and the creation of dead zones . This can result in reductions in water quality, fish, and other animal populations. Overfishing also occurs. Chesapeake Bay once had a flourishing oyster population that has been almost wiped out by overfishing. Oysters filter these pollutants, and either eat them or shape them into small packets that are deposited on

8610-422: The marine environment, such as plastics , pesticides , furans , dioxins , phenols and heavy metals . Such toxins can accumulate in the tissues of many species of aquatic life in a process called bioaccumulation . They also accumulate in benthic environments, such as estuaries and bay muds : a geological record of human activities of the last century. The elemental composition of biofilm reflect areas of

8715-575: The marsh causing increased rates of erosion . A similar phenomenon occurs in mangrove swamps , which are another potential ecosystem in estuaries. An increase in nitrogen causes an increase in shoot growth and a decrease in root growth. Weaker root systems cause a mangrove tree to be less resilient in seasons of drought, which can lead to the death of the mangrove. This shift in above ground and below ground biomass caused by eutrophication could hindered plant success in these ecosystems. Across all biomes, eutrophication often results in plant death but

8820-542: The middle of the valley, the farm operations are found farther to the west and east sides than in earlier decades. The northern reaches of Antelope Valley are part of the Tehachapi Wind Resource Area , the largest wind resource area in California. The valley also has numerous solar farms , some of which are among the largest in the United States . The world's largest open-pit borax mine

8925-508: The mountain, canyon, and desert areas one may find Vasquez Rocks Natural Area Park , where many old Westerns were filmed. Mount Wilson Observatory in the San Gabriel Mountains is open for the public to view astronomical stars from its telescope, now computer-assisted. Many county residents find relaxation in water skiing and swimming at Castaic Lake Recreation Area – the county's largest park by area – as well as enjoying natural surroundings and starry nights at Saddleback Butte State Park in

9030-581: The newly dedicated Mojave Air and Space Port . The spaceport is famous as the base of operations for Scaled Composites , the company that designed SpaceShipOne and won the X-Prize . Much of the work done at these facilities is performed in coordination with Edwards Air Force Base and the NASA Dryden Flight Research Center (see above), from the creation and testing of proof-of-concept X-planes, to Space Shuttle operations, to

9135-440: The now off-balance nitrogen cycle , estuaries can be driven to phosphorus limitation instead of nitrogen limitation. Estuaries can be severely impacted by an unbalanced phosphorus cycle, as phosphorus interacts with nitrogen and silica availability. With an abundance of nutrients in the ecosystem, plants and algae overgrow and eventually decompose, which produce a significant amount of carbon dioxide. While releasing CO 2 into

9240-617: The population. Hispanic or Latino residents of any race numbered 4,687,889 (48%); 36% of Los Angeles County's population was of Mexican ancestry, 3.7% Salvadoran, and 2.2% Guatemalan heritage. The county has a large population of Asian Americans , being home to the largest numbers of Burmese , Cambodian , Chinese , Filipino , Indonesian , Korean , Sri Lankan , Taiwanese , and Thai outside their respective countries. The largest Asian groups in Los Angeles County are 4.0% Chinese, 3.3% Filipino, 2.2% Korean, 1.0% Japanese, 0.9% Vietnamese, 0.8% Indian, and 0.3% Cambodian. The racial makeup of

9345-481: The properties is a church building that was used as a filming location for Kill Bill . The code enforcers have arrived on some of their visits in SWAT -team formats. Hispanics and Whites make up the majority of the population. Spanish and Tagalog are the most common foreign languages spoken in the Antelope Valley. According to Mapping L.A. , German and English were the most common ancestries and Mexico and

9450-427: The seawater in a layer that gradually thins as it moves seaward. The denser seawater moves landward along the bottom of the estuary, forming a wedge-shaped layer that is thinner as it approaches land. As a velocity difference develops between the two layers, shear forces generate internal waves at the interface, mixing the seawater upward with the freshwater. An examples of a salt wedge estuary is Mississippi River and

9555-411: The sediment which has a very high oxygen demand. This reduces the levels of oxygen within the sediment often resulting in partially anoxic conditions, which can be further exacerbated by limited water flow. Phytoplankton are key primary producers in estuaries. They move with the water bodies and can be flushed in and out with the tides . Their productivity is largely dependent upon the turbidity of

9660-485: The southeast. Edwards Air Force Base lies east of Rosamond , 37 miles (60 km) northeast of Palmdale . Edwards AFB's dry lakebeds are the lowest geographic elevation in the valley. Significant numbers of U.S. military test flights are performed there, and it has been the site of many important aeronautical accomplishments, including the first flight to break the sound barrier , accomplished by Chuck Yeager. NASA Space Shuttles originally landed at Edwards because

9765-423: The state Legislature to authorize the transfer of all courthouses to the state government in 2008 and 2009 (so that judges would have direct control over their own courthouses). Courthouse security is still provided by the county government under a contract with the state. Unlike the largest city in the United States, New York City , all of the city of Los Angeles and most of its important suburbs are located within

9870-422: The time of statehood in 1850. The county originally included parts of what are now Kern , San Bernardino , Riverside , Inyo , Tulare , Ventura , and Orange counties. In 1851 and 1852, Los Angeles County stretched from the coast to the state line of Nevada . As the population increased, sections were split off to organize San Bernardino County in 1853, Kern County in 1866, and Orange County in 1889. Before

9975-1022: The urban areas of the county. Charismatic biodiversity indicator species native to the area include three species of amphibian ( Baja California chorus frog , black-bellied slender salamander , western toad ), 14 species of bird ( acorn woodpecker , California quail , canyon wren , cinnamon teal , great blue heron , great horned owl , greater roadrunner , hooded merganser , Northern harrier , red-tailed hawk , red-winged blackbird , spotted towhee , western bluebird , western meadowlark ), nine kinds of invertebrates ( Behr's metalmark , bramble green hairstreak , bumblebees , El Segundo blue butterfly , harvester ants , Lorquin's admiral , North American Jerusalem crickets , Sara orangetip , velvet ants ), five mammals ( bobcat , dusky footed woodrat , gray fox , mountain lion , mule deer ), and six reptiles ( California kingsnake , coachwhip snake , gopher snake , side-blotched lizard , western pond turtle , western rattlesnake ). Any observations of these species within

10080-456: The volume of freshwater, the tidal range, and the extent of evaporation of the water in the estuary. Drowned river valleys are also known as coastal plain estuaries. In places where the sea level is rising relative to the land, sea water progressively penetrates into river valleys and the topography of the estuary remains similar to that of a river valley. This is the most common type of estuary in temperate climates. Well-studied estuaries include

10185-453: The water and atmosphere, these organisms are also intaking all or nearly all of the available oxygen creating a hypoxic environment and unbalanced oxygen cycle . The excess carbon in the form of CO 2 can lead to low pH levels and ocean acidification , which is more harmful for vulnerable coastal regions like estuaries. Eutrophication has been seen to negatively impact many plant communities in estuarine ecosystems . Salt marshes are

10290-835: The water. The main phytoplankton present are diatoms and dinoflagellates which are abundant in the sediment. A primary source of food for many organisms on estuaries, including bacteria , is detritus from the settlement of the sedimentation. Of the thirty-two largest cities in the world in the early 1990s, twenty-two were located on estuaries. As ecosystems, estuaries are under threat from human activities such as pollution and overfishing . They are also threatened by sewage, coastal settlement, land clearance and much more. Estuaries are affected by events far upstream, and concentrate materials such as pollutants and sediments. Land run-off and industrial, agricultural, and domestic waste enter rivers and are discharged into estuaries. Contaminants can be introduced which do not disintegrate rapidly in

10395-510: The whole county, like posting of restaurant ratings, must be ratified by the individual city). As an executive body, it can tell the county departments what to do, and how to do it. As a quasi-judicial body, the Board is the final venue of appeal in the local planning process, and holds public hearings on various agenda items. As of 2020, the Board of Supervisors oversees a $ 35.5 billion annual budget and over 112,000 employees. The county government

10500-466: Was 32 years. For every 100 females, there were 97.7 males. For every 100 females age 18 and over, there were 95.0 males. The median personal earnings for all workers 16 and older in Los Angeles County are $ 30,654, slightly below the US median; earnings, however vary widely by neighborhood, race and ethnicity, and gender. The median household income was $ 42,189 and the median family income was $ 46,452. Males had

10605-568: Was almost evenly split over Proposition 8 , which amended the California Constitution to ban same-sex marriages. The county voted for the amendment 50.04% with a margin of 2,385 votes. The Los Angeles County Superior Court is the county's court of general jurisdiction, while the U.S. District Court for the Central District of California may hear cases where federal jurisdiction is present. Both are headquartered in

10710-666: Was also partly filmed in Antelope Valley. The video to the R.E.M. song " Man on the Moon " was shot in Antelope Valley in October 1992. Major hospitals include: The Antelope Valley was formerly served by a county hospital, High Desert Hospital, which was converted into an urgent care clinic in 2003 due to the county's budget problems. As a result, indigent patients with serious but non-life-threatening medical conditions must seek treatment at Olive View – UCLA Medical Center in Sylmar, which

10815-647: Was founded for the X-1 program. The Space Shuttle orbiter was serviced there when it landed at Edwards. U. S. Air Force Plant 42 in northeast Palmdale is home to Lockheed Martin , Boeing , Northrop Grumman , and BAE Systems , among other aerospace-related companies. Notable projects assembled and/or designed there include the Space Shuttle orbiters , B-1 Lancer bombers, B-2 Spirit bombers, F-117 Nighthawk fighters, F-35 Joint Strike Fighters , and Lockheed L-1011 Tristar passenger jets. This region also houses

10920-409: Was named. Unusually heavy snows in both the mountains and the valley floor drove the antelope toward their normal feeding grounds in the eastern part of the valley. Since they would not cross the railroad tracks , many of them starved to death. The remainder of these pronghorns were hunted for their hides by settlers. Once abundant, they either died off or migrated into the Central Valley . A drought in

11025-478: Was once under Mexican rule and was named after the large herds of antelope. In recent decades, the valley has become a bedroom community to the Greater Los Angeles area . Major housing-tract development and population growth took off beginning in 1983, which has increased the population of Palmdale around 12 times its former size as of 2006. Neighboring Lancaster has increased its population since

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