Amazon basin in the context of "Brazil"

Peru, officially the Republic of Peru, is a country in western South America. It is bordered to the north by Ecuador and Colombia, to the east by Brazil, to the southeast by Bolivia, to the south by Chile, and to the south and west by the Pacific Ocean. Peru is a megadiverse country, with habitats ranging from the arid plains of the Pacific coastal region in the west, to the peaks of the Andes mountains extending from the north to the southeast of the country, to the tropical Amazon basin rainforest in the east with the Amazon River. Peru has a population of over 32 million, and its capital and largest city is Lima. At 1,285,216 km (496,225 sq mi), Peru is the 19th largest country in the world, and the third largest in South America.

Peruvian territory was home to several cultures during the ancient and medieval periods, and has one of the longest histories of civilization of any country, tracing its heritage back to the 10th millennium BCE Caral–Supe civilization, the earliest civilization in the Americas and considered one of the cradles of civilization. Notable succeeding cultures and civilizations include the Nazca culture, the Moche, Wari and Tiwanaku empires, the Kingdom of Cusco, and the Inca Empire, the largest known state in the pre-Columbian Americas. The Spanish Empire conquered the region in the 16th century and Charles V established a viceroyalty with the official name of the Kingdom of Peru that encompassed most of its South American territories, with its capital in Lima. Higher education started in the Americas with the official establishment of the National University of San Marcos in Lima in 1551.

The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America. When viewed as a single continent, the Americas are the 2nd largest continent by area after Asia and the 3rd largest continent by population. The Americas make up most of the land in Earth's Western Hemisphere and constitute the New World.

Along with their associated islands, the Americas cover 8% of Earth's total surface area and 28.4% of its land area. The topography is dominated by the American Cordillera, a long chain of mountains that runs the length of the west coast. The flatter eastern side of the Americas is dominated by large river basins, such as the Amazon, St. Lawrence River–Great Lakes, Mississippi, and La Plata basins. Since the Americas extend 14,000 km (8,700 mi) from north to south, the climate and ecology vary widely, from the arctic tundra of Northern Canada, Greenland, and Alaska, to the tropical rainforests in Central America and South America.

Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco, warm valleys, high-altitude Andean plateaus, and snow-capped peaks, encompassing a wide range of climates and biomes across its regions and cities. It includes part of the Pantanal, the largest tropical wetland in the world, along its eastern border. It is bordered by Brazil to the north and east, Paraguay to the southeast, Argentina to the south, Chile to the southwest, and Peru to the west. The seat of government is La Paz, which contains the executive, legislative, and electoral branches of government, while the constitutional capital is Sucre, the seat of the judiciary. The largest city and principal industrial center is Santa Cruz de la Sierra, located on the Llanos Orientales (eastern tropical lowlands), a mostly flat region in the east of the country with a diverse non-Andean culture.

The sovereign state of Bolivia is a constitutionally unitary state divided into nine departments. Its geography varies as the elevation fluctuates, from the western snow-capped peaks of the Andes to the eastern lowlands, situated within the Amazon basin. One-third of the country is within the Andean mountain range. With an area of 1,098,581 km (424,164 sq mi), Bolivia is the fifth-largest country in South America after Brazil, Argentina, Peru and Colombia, and, alongside Paraguay, is one of two landlocked countries in the Americas. It is the largest landlocked country in the Southern Hemisphere. Bolivia had a population of 11.4 million as of the latest census in 2024. It is multiethnic, including Amerindians, Mestizos, and the descendants of Europeans and Africans. Spanish is the official and predominant language, although 36 indigenous languages also have official status, of which the most commonly spoken are Guaraní, Aymara, and Quechua.

The Amazon River (US: /ˈæməzɒn/; Portuguese: rio Amazonas, Spanish: río Amazonas) in South America is the largest river by discharge volume of water in the world, and the longest or second-longest river system in the world, a title which is disputed with the Nile.

The headwaters of the Apurímac River on Nevado Mismi had been considered, for nearly a century, the Amazon basin's most distant source until a 2014 study found it to be the headwaters of the Mantaro River on the Cordillera Rumi Cruz in Peru. The Mantaro and Apurímac rivers join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, forming what countries other than Brazil consider to be the main stem of the Amazon. Brazilians call this section the Solimões River above its confluence with the Rio Negro forming what Brazilians call the Amazon at the Meeting of Waters (Portuguese: Encontro das Águas) at Manaus, the largest city on the river.

The Río de la Plata basin (Spanish: Cuenca del Plata, Portuguese: Bacia do Prata), more often called the River Plate basin in scholarly writings, sometimes called the Platine basin or Platine region, is the 3,170,000-square-kilometre (1,220,000 sq mi) hydrographical area in South America that drains to the Río de la Plata. It includes areas of southeastern Bolivia, southern and central Brazil, the entire country of Paraguay, most of Uruguay, and northern Argentina. Making up about one fourth of the continent's surface, it is the second largest drainage basin in South America (after the Amazon basin) and one of the largest in the world.

The main rivers of the La Plata basin are the Paraná River, the Paraguay River (the Paraná's main tributary), and the Uruguay River.

A diatom (Neo-Latin diatoma) is any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's biomass. They generate about 20 to 50 percent of the oxygen produced on the planet each year, take in over 6.7 billion tonnes of silicon each year from the waters in which they live, and constitute nearly half of the organic material found in the oceans. The shells of dead diatoms are a significant component of marine sediment, and the entire Amazon basin is fertilized annually by 27 million tons of diatom shell dust transported by transatlantic winds from the African Sahara, much of it from the Bodélé Depression, which was once made up of a system of fresh-water lakes.

Diatoms are unicellular organisms: they occur either as solitary cells or in colonies, which can take the shape of ribbons, fans, zigzags, or stars. Individual cells range in size from 2 to 2000 micrometers. In the presence of adequate nutrients and sunlight, an assemblage of living diatoms doubles approximately every 24 hours by asexual multiple fission; the maximum life span of individual cells is about six days. Diatoms have two distinct shapes: a few (centric diatoms) are radially symmetric, while most (pennate diatoms) are broadly bilaterally symmetric.