Clear water flow
In addition to black water rivers and white water rivers, clear water rivers are among the three dominant river types in the tropics . Clear water rivers originate in the area of tertiary deposits or Paleozoic mountains and are poor in sediments and electrolytes . The conductivity of the water is low; Nitrogen and phosphorus are present in small amounts. Due to the good lighting conditions and the constant availability of nutrients - although comparatively few, but not long incorporated - primary production is very high. The rivers are poor in molluscs . The pH value fluctuates between acidic and neutral, between 4.5 and 7.8 in total, and between 6.0 and 6.7 in the larger rivers.
Clear water rivers can only be found in South America and have a characteristic yellow to olive green color. The bottom of these rivers mostly consists of sand or rock. The visibility under water is up to four meters. Despite the low nutrient content, a diverse environment has developed in clear water rivers, but it does not quite come close to the diversity in the vicinity of white water rivers. In contrast to white and black water rivers, flooding in clear water rivers is rare. Typical and important representatives of this type of rivers are the Rio Guaporé , the Rio Tapajós , the Rio Xingú and the Rio São Francisco .
Streams are rare in the tropical rainforests because of the high suction power of the trees. The primeval forests of the Amazon basin are an exception , they are numerous there. The majority of these streams are low-electrolyte clear water streams, white and black water streams are rare.
literature
- Wilfried Schönborn: Textbook of Limnology . E. Schweizerbart'sche Verlagbuchhandlung, Stuttgart 2003, ISBN 3-510-65204-5
Web links
- Limnology: clear water flow on www.latein America-studien.at
Individual evidence
- ^ A b Wilfried Schönborn: Textbook of Limnology . Page 368 ff, see literature
- ↑ Harald Sioli (Ed.): The Amazon - Limnology and landscape ecology of a mighty tropical river and its basin . Dr W. Junk Publishers, Dordrecht 1984, ISBN 90-6193-108-8 , page 370