its upper and middle course. Lower course After the Marié River enters the Rio Negro the river continues its eastward course forming many large islands and becoming very wide at several locations. It passes local communities such as Santa Isabel do Rio Negro. During the wet season, the river floods the country far and wide here, sometimes to a width of , for long distances. During this season, from April until October, it is a succession of lagoons, full of long islands and intricate channels with a lot of water wildlife. Near Carvoeiro the last major tributary of the Rio Negro, the Branco River joins the Rio Negro and the river temporarily forms the border between the state of Roraima and Amazonas State, Brazil. The river now takes a more southeastern course, becoming again very wide in many stretches before reaching the biggest city on its course Manaus. The Anavilhanas National Park, a conservation unit that was originally an ecological station created in 1981, protects part of the Anavilhanas river archipelago in this part of the river. Below the archipelago, it meets the Solimões River to form the Amazon River, creating a phenomenon known as the Meeting of Waters. History The river was named by the Spanish explorer Francisco de Orellana, who first came upon it in 1541. By the middle of the 17th century, Jesuits had settled along its banks in the midst of numerous tribes: Manau, Aruák, and Trumá Indians. After 1700 slaving along the river was common, and Native American populations were greatly diminished after contact with Eurasian diseases. This area was the filming location for Survivor:The Amazon in 2003. Fauna and Flora While the name Rio Negro means Black River, its waters are similar in color to strong tea, which is typical of blackwater rivers. The dark color comes from humic acid due to an incomplete breakdown of phenol-containing vegetation from sandy clearings. The river was named because it looks black from a distance. Much has been written on the productivity of the Rio Negro and other blackwater rivers. The older idea that these are "hunger rivers" is giving way, with new research, to the recognition that the Rio Negro, for example, supports a large fishing industry and has numerous turtle beaches. If explorers did not find many Indigenous peoples along the Rio Negro during the 17th century, it is likely that their populations were reduced