The negro river is the world’s largest black water river and the second in water volume – being the Amazon the first, which Negro river helps to form. 81% of its total length are in brazil, 11% in Colombia, 8% in Venezuela and a little portion in Guiana (1,7% of its total). The Negro river flows into the rio Solimões to form the Amazon river, just below Manaus.
It runs through 1.700km (more than 1,000 miles) and the water volume that flows through its channel is more than all the european rivers united. In some areas it can have more than 32 km (20 miles) wide and it has more than a thousand island grouped into two archipelagos: Anavilhanas, closer to Manaus and Mariuá, at Barcelo’s region. Both are the world’s biggest fluvial archipelagos.
It is an Amazonian region in which the social and environmental unity – populated watershed and traditionally used by a group of people – shows a great diversity. The greater portion of the region is composed by indigenous land and conservation unties
The black water rivers have this dark coloration due to the presence of large quantities of dissolved organic substances that are originated from the decomposition of organic matter at the sandy soils. The dense and continuous canopy layer is the most efficient protection against soil erosion. Due to the low ph, insects do not proliferate and there are very few mosquitoes in the region. The Negro River’s flora is composed by bushes, terrestrial herbs, epiphytes (plants that lives on tree branches or trunks, without any connection with the ground), hemiepiphytes (also live up on the trees but do touch the ground at some point of its life) and trees, that are our greater interest. The trees are very large and high, with a single trunk going from the ground until the canopy. They can be used as home for other plants (vines and epiphytes). The trees called emergents are the ones that stand out from the others because they’re taller than most (Brazilian nut, mahogany, samauma, angelim).
Anavilhanas National Park
A complex of more than 400 islands with hundreds of lakes and channels, compose the famous Anavilhanas, which is located between the cities of Manaus and Novo Airão. Due to the great biodiversity and distinct ecosystems, at 1981 it was promoted to the category of ecological station, and since then it is part of the group of conservation unities of the lower Negro river. Anavilhanas is the second world’s largest fluvial archipelagos, losing only to Mariuá, which is also at the Negro river, close to the city of Barcelos.
The formation of the islands are due to the flocculation (sedimentation of solid particles) of the Branco River, which over hundreds of years helped to form the archipelago. But they are in constant change, because there is a continuous process of sedimentation and erosion due to the change of water level, according to the season, making the islands “move” over time.
The islands are home to many endangered species such as the harpy eagle, the jaguar, the pirarucu and the spider monkey. It is also home to some endemic species such as the “vinegar dog” and others. Another curiosity is that it this is the only place where it is possible to see every alligator species in the amazon.
Jaú National Park
Created in 1980, the jaú national park is Brazil’s largest park and the world’s largest humid, continuous and intact equatorial forest park. It is located at the cities of Novo Airão and Barcelos, 220km from Manaus, in a straight line. The name was picked in honor for one of Brazil’s biggest fish, the Jaú, which is also the name of the park’s main river. It is part of the central ecological corridor of the Amazon and it is a natural world heritage site (Unesco 2002).
Even being a little far away, it does worth a visit, there are many different attraction and tours to do, such as observation of fauna and flora, many baths at the rapids or at the beaches, visit the community of “ribeirinhos” (river people). There are also many petroglyph at the ruins of the city on old Airão, which shows that the area has been occupied by man for a long time.
Its vegetation is composed by dense tropical forest, igapó (flooded forest) vegetation, campinaranas, swamps and grasslands. Jaú also has numerous endangered species such as reptiles, bird, mammals, amphibian, etc.