Waterways off the Rio Negro in Brazil. (Courtesy of NASA)
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Chapter 6:
RAINFOREST WATERS
Tropical rainforests have some of the largest rivers in the world, like the Amazon, Madeira, Mekong, Negro, Orinoco,
and Zaire (Congo), because of the tremendous amount of precipitation their watersheds receive. These mega-rivers
are fed by countless smaller tributaries, streams, and creeks. For example, the Amazon alone has some 1,100 tributaries,
17 of which are over 1,000 miles long. Although large tropical rivers are fairly uniform in appearance and water
composition, their tributaries vary greatly. Many tropical rivers and streams have extreme high and low water levels
that occur at different parts of the year.
In addition to rivers, rainforests have conventional, free-standing lakes and so-called oxbow lakes, formed when
a river changes course. These lakes are home to species adapted to the quiet, stagnant conditions.
Tropical waters, whether they be giant rivers, streams, or oxbow lakes, are almost as rich in animal species as
the rainforests that surround them. But they, too, are increasingly threatened by human activities, including
pollution, siltation resulting from deforestation, hydroelectric projects, and over-harvesting of resident species.
Review questions:
- Why are some of the world's largest rivers found in tropical regions?
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Continued: Rainforest rivers
This article was written by Rhett A. Butler [bibliographic citation for this page] and was last updated on the most recent date listed in the column on the right side.
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Recent news
Exploring Asia's lost world
(05/03/2012) Abandoned by NGOs and the World Bank, carved out for rubber plantations and mining by the Cambodian government, spiraling into a chaos of poaching and illegal logging, and full of endangered species and never-explored places, Virachey National Park may be the world's greatest park that has been written off by the international community. But a new book by explorer and PhD student, Greg McCann, hopes to change that. Entitled Called Away by a Mountain Spirit: Journey to the Green Corridor, the book highlights expeditions by McCann into parts of Virachey that have rarely been seen by outsiders and have never been explored scientifically, including rare grasslands that once housed herds of Asian elephants, guar, and Sambar deer, before poachers drove them into hiding, and faraway mountains with rumors of tigers and mainland Javan rhinos.
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Will mega-dams destroy the Amazon?
(04/18/2012) More than 150 new dams planned across the Amazon basin could significantly disrupt the ecological connectivity of the Amazon River to the Andes with substantial impacts for fish populations, nutrient cycling, and the health of Earth's largest rainforest, warns a comprehensive study published in the journal PLoS ONE. Scouring public data and submitting information requests to governments, researchers Matt Finer of Save America’s Forests and Clinton Jenkins of North Carolina State University documented plans for new dams in Bolivia, Brazil, Colombia, Ecuador, and Peru.
Pictures: Destruction of the Amazon's Xingu River begins for Belo Monte Dam
(04/18/2012) The Xingu River will never be the same. Construction of Belo Monte Dam has begun in the Brazilian Amazon, as shown by these photos taken by Greenpeace, some of the first images of the hugely controversial project. Indigenous groups have opposed the dam vigorously for decades, fearing that it will upend their way of life. Environmentalists warn that the impacts of the dam—deforestation, methane emissions, and an irreparable changes to the Xingu River's ecosystem—far outweigh any benefits. The dam, which would be the world's third largest, is expected to displace 16,000 people according to the government, though some NGOs put the number at 40,000. The dam will flood over 40,000 hectares of pristine rainforest, an area nearly seven times the size of Manhattan.
Judge suspends Brazilian dam that would flood sacred waterfalls
(04/02/2012) A federal judge has suspended the construction of a 1,820 megawatt dam on the Teles Pires River in the Amazon. The judge found that indigenous communities were not properly consulted about the dam, which would flood a sacred site, known as the Seven Waterfalls, as well as imperil the livelihoods of indigenous fishermen.
More rainforest news
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