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Rio Poranga, upper Rio Negro, Brazil

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Brazil, State of Amazonas, Sao Gabriel da Cachoeira

The Rio Poranga in the vicinity of Sao Gabriel da Cachoeira, Sao Gabriel is considered the third largest municipality of Brazil in territorial extension, according to the Brazilian Institute of Geography and Statistics. The Rio Poranga is a small affluent of the upper Rio Negro.

It is quite small and compared to other rivers in Brazil it is only a stream, it has a astonishing number of species including two Corydoras species described from this stream namely Corydoras duplicareus and Corydoras serratus.

The area is surrounded by dense jungle and a, as any rainforest, astounding number of tree species. The stream itself is quite fast flowing and therefore has less tannins than the rest of the Rio Negro, although the bottom is littered with leaves and branches.

Submitted by
Johannes H Steen
Approved by
Roberto E. Reis, Pablo C. Lehmann and Flávio Lima
GPS
1.1269666, -66.8424759
Geographical region
South America
Drainage Basin
Rio Amazonas
River catchment
Upper Rio Negro
Water body type
Stream
Water body name
Rio Poranga
Water body part
Channel
Water body course
Upper course
Water body: tributary of
Rio
Tributary name
Rio Poranga

Videos above and below water

Water Chemistry

Water information

Water type
Fresh water
Water color
Black water
Water transparency
Medium
Concentration of sediments
Low
Water temperature
26 °C
Water flow/curent
Strong

Chemical parameters

pH
5
Conductivity
20
GH
2 mg/l
KH
0
Dissolved Oxygen
40 %

Substrate in nature

Sand
White
Pebble/Gravel
None
Stone
None
Stone form
Silt/Mud
Brown
Leaves
Adundant
Driftwood
Many
Submerged terrestrial vegetation
Yes

Aquatic Biotope

Date of collecting
Not sure but 1995
Collecting area
River bank
Water depth
0,2m
Air temperature
28 °C
Sunlight
No sunlight

Environment

Environment
Affected by human activity
Affected by human activity
Agriculture
Agriculture
Little
Surrounding area

The surrounding area is a dense jungle totally surrounding the upper Rio Negro of which the Rio Poranga is a affluent of. It is located roughly 8 kilometres north of the Nobuo Oba (Área Capitão Nobuo Oba s/nº – Cachoeirinha – São Gabriel da Cachoeira). It is very close to the border of Venezuela and Colombia.

Terrestrial vegetation:

  • Hevea sp. (Euphorbiaceae)
  • Bertholletia excelsa (Lecythidaceae)
Underwater landscape

The water course of this river and generally the whole Rio Negro bottom is covered in leaf litter, twigs and branches. The banks have an astonishing amount of fallen tree and the root systems of trees.

The typical biotope of the Rio Poranga is fast flowing and also includes a lot of mimicry specifically in catfishes there of two wich are described from here, the species that mimic eachother are: Brachyrhamdia imitator, Corydoras duplicareus, Corydoras serratus and a species similar to Corydoras imitator.

Fish:

  • Apistogramma mendezi (Cichlidae)
  • Nannostomus sp. (Lebiasinidae)
  • Hemigrammus coeruleus (Characidae)
  • Hyphessobrycon sp. (Characidae)
  • Hyphessobrycon epicharis (Characidae)
  • Corydoras duplicareus (Callichthyidae)
  • Corydoras serratus (Callichthyidae)

Aquatic vegetation:

  • Alternanthera reineckii (Amaranthaceae)
  • Myriophyllum sp. (Haloragaceae)
Threats to ecology

Rivers like this are extremely important to the ecosystem and biodiversity as a whole. These streams run through the forest and distributes nutrients which are a scarce source in the Amazon, the river also hosts several species or subspecies wich are only found there.

The major threats to the ecology of the Amazon is logging wich dries out and erodes whole rivers and goldmining which pollutes the river to an extent which makes it dangerous for even humans to live there.

Riparian zone

Trees near the aquatic habitat
Many -

Comment by the expert

Roberto E. Reis: Description of the location general, and description of surroundings too wide. Description of threats include logging and mining. One video and four photos of the biotope. Seven fish and two aquatic plant species listed. Description of the aquatic habitat, riparian zone, and underwater landscape reasonable. Bibliography/Sitography weak.

Flávio Lima: The participant has done na adequate research job, using videos from the locality that he recreated and the sparse literature available for this specific habitat.

Pablo C. Lehmann: Very well characterized natural biotope, with good quality visual supports representative of the natural habitat.