Nutrient cycling in the Columbia River Basin - meaning and definition. What is Nutrient cycling in the Columbia River Basin
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What (who) is Nutrient cycling in the Columbia River Basin - definition

Nutrient cycling in the Columbia River Basin         
  • Cascades Rapids prior to construction of the Bonneville Dam.
  • Map of Columbia River Basin showing locations of dams throughout the basin.  The large number of dams has had measurable and lasting impact on the nutrient cycling thought the basin <ref name=":3" /><ref name=":9" /> - dams shown in red and yellow.
  • Columbia Basin]]
  • Aerial view of&nbsp;Columbia River&nbsp;and Bonneville Dam
  • Red bloom in a harbor. The vibrant color of the blooms attracts attention from scientists and local community members.
Nutrient cycling in the Columbia River Basin involves the transport of nutrients through the system, as well as transformations from among dissolved, solid, and gaseous phases, depending on the element. The elements that constitute important nutrient cycles include macronutrients such as nitrogen (as ammonium, nitrite, and nitrate), silicate, phosphorus, and micronutrients, which are found in trace amounts, such as iron.
Columbia River         
  • Near [[The Gorge Amphitheatre]] in [[George, Washington]]
  • [[Multnomah Falls]], painted by James W. Alden, 1857
  • Dipnet fishing at Celilo Falls, 1941
  • [[Chief Joseph]] of the [[Nez Perce people]]
  • The [[Columbia River Gorge]] facing east toward [[Beacon Rock]]
  • Panoramic view of Columbia River Gorge from [[Dog Mountain]] in Washington
  • Rowena Crest]]
  • Benson log raft]], containing an entire year's worth of logs from one timber camp, heads downriver in 1906
  • [[Bathymetric]] map of the mouth of the Columbia River
  • Course of the Columbia River
  • Private}}
  • Beacon Rock]] is visible on the left.
  • Eagle Creek]] in Oregon, November 2007.
  • The Deschutes River at its confluence with the Columbia
  • [[Drumheller Channels]], part of the [[Channeled Scablands]] formed by the [[Missoula Floods]]
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  • Nuclear reactors at the [[Hanford Site]] along the river
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  • Kinbasket Lake, a reservoir on the Columbia River
  • alt=View of an overgrown field with a rotting fencepost in the foreground and a range of hills in the distance
  • See complete map.]])
  • Seining]] salmon on the Columbia River, 1914
  • Hassalo]]'' runs the [[Cascades Rapids]], May 26, 1888. The rapids are now submerged under the pool of the [[Bonneville Dam]].
  • The mouth of the Columbia is just past [[Astoria, Oregon]]; ships must navigate the treacherous [[Columbia Bar]] (near horizon, not visible in this picture) to enter or exit the river.
  • Mountains of Bright Stone]]
  • ''Roll on, Columbia, roll on, roll on, Columbia, roll on / Your power is turning our darkness to dawn / Roll on, Columbia, roll on.''
Lyrics from [[Woody Guthrie]]'s 1941 song [[Roll on Columbia]], written for the [[Bonneville Power Administration]].
Columbia river; The Columbia river; Columbia River (Canada and the United States); River of the West; Columbia River/infobox; ColumbiaRiverGeobox; Colombia river; Colombia River; Pollution of the Columbia River; River Columbia; Mid-Columbia Basin

The Columbia River (Upper Chinook: Wimahl or Wimal; Sahaptin: Nch’i-Wàna or Nchi wana; Sinixt dialect swah'netk'qhu) is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada. It flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state of Oregon before emptying into the Pacific Ocean. The river is 1,243 miles (2,000 km) long, and its largest tributary is the Snake River. Its drainage basin is roughly the size of France and extends into seven US states and a Canadian province. The fourth-largest river in the United States by volume, the Columbia has the greatest flow of any North American river entering the Pacific. The Columbia has the 36th greatest discharge of any river in the world.

The Columbia and its tributaries have been central to the region's culture and economy for thousands of years. They have been used for transportation since ancient times, linking the region's many cultural groups. The river system hosts many species of anadromous fish, which migrate between freshwater habitats and the saline waters of the Pacific Ocean. These fish—especially the salmon species—provided the core subsistence for native peoples.

The first documented European discovery of the Columbia River occurred when Bruno de Heceta sighted the river's mouth in 1775. In the late 18th century, a private American ship became the first non-indigenous vessel to enter the river; in 1792, William Robert Broughton of the British Royal Navy commanding the HMS Chatham as part of the Vancouver Expedition, navigated past the Oregon Coast Range into the Willamette Valley. In the following decades, fur-trading companies used the Columbia as a key transportation route. Overland explorers entered the Willamette Valley through the scenic, but treacherous Columbia River Gorge, and pioneers began to settle the valley in increasing numbers. Steamships along the river linked communities and facilitated trade; the arrival of railroads in the late 19th century, many running along the river, supplemented these links.

Since the late 19th century, public and private sectors have extensively developed the river. To aid ship and barge navigation, locks have been built along the lower Columbia and its tributaries, and dredging has opened, maintained, and enlarged shipping channels. Since the early 20th century, dams have been built across the river for power generation, navigation, irrigation, and flood control. The 14 hydroelectric dams on the Columbia's main stem and many more on its tributaries produce more than 44 percent of total U.S. hydroelectric generation. Production of nuclear power has taken place at two sites along the river. Plutonium for nuclear weapons was produced for decades at the Hanford Site, which is now the most contaminated nuclear site in the United States. These developments have greatly altered river environments in the watershed, mainly through industrial pollution and barriers to fish migration.

Chad Basin         
  • Benue trough.  The northwest and east extensions lie below the Chad Basin. ("Tibesti-Cameroon Trough" is not shown.)
  • States in the Sahel / Savanna around 1750
  • [[Chari River]] basin
  • People at a coronation in Chad, 2005
  • Dunes in the [[Erg of Bilma]]
  • [[Abéché]], capital of Wadai, in 1918 after the French had taken over
  • The eastern part of the basin, showing the [[Holocene]] "Mega Chad" lake (blue area) at its maximum size with the Chari in the south and the Benue in the south west. The modern [[Lake Chad]] is in the centre of this map, in green.
Lake Chad basin; Lake Chad Basin; Chad basin; Yedseram River valley; Lake Chad Catchment
The Chad Basin is the largest endorheic basin in Africa, centered on Lake Chad. It has no outlet to the sea and contains large areas of semi-arid desert and savanna.