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#5413 Small Rio Negro tributary near Manaus, Brazil

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Brazil, Amazonas, Manaus

My simulated environment is the Negro River near Manaus. Manaus is located in the northwest of Brazil, on the left bank of the Negro River.

In the dry season the water level of this small tributary is very low. Under the scouring of the river, a large number of roots are exposed, and there are many dead leaves in the bottom. A large amount of humus colours the water yellow.

It’s a paradise for small fish, rich in food resources, and there are many shelters underwater, giving birth to many lives. There are abundant terrestrial plants here, with short trees, slender trunks and tree growth layers. Light-colored dry and hot deciduous bushes account for the largest proportion among these plants. Because of the acid water quality, there are basically no plants underwater.

Submitted by
Wang Qiliang
GPS
-3.1220734, -60.0293579
Geographical region
South America
Drainage Basin
Rio Amazonas
River catchment
Rio Negro
Water body type
Wetland
Water body name
Rio Negro
Water body part
River mouth
Water body course
Lower course
Water body: tributary of
Rio
Tributary name
Negro

Videos above and below water

Water Chemistry

Water information

Water type
Fresh water
Water color
Mixed water
Water transparency
Medium
Concentration of sediments
High
Water temperature
25-28 °C
Water flow/curent
Slow

Chemical parameters

pH
5
Conductivity
50
GH
KH
Dissolved Oxygen
45 %

Substrate in nature

Sand
Beige
Pebble/Gravel
None
Stone
None
Stone form
Silt/Mud
Beige
Leaves
Many
Driftwood
Many
Submerged terrestrial vegetation
No

Aquatic Biotope

Date of collecting
Collecting area
River bank
Water depth
0,2m
Air temperature
Sunlight
Partial shade

Environment

Environment
Affected by human activity
Affected by human activity
Pollution
Pollution
Advanced
Surrounding area

The Rio Negro River, is the largest tributary of the North Bank of the Amazon River. Its source is the Orinoco River and the Amazon River watershed, it and Orinoco River between the Casiquiare river. The total length of the Negro River is 2550-2252.6km, the drainage area is 620000 square kilometers, the annual average flow is 30000m3/sec., the average annual runoff depth is 1600mm, and the suspended load concentration is 0.007kg/m3.

The largest tributary of the lower reaches of the Negro River is Rio Branco. The middle and lower tributaries include the Mucajai River, Ajarani River, Anaua River and Catrimani river. It flows into the Amazon River 17km below Manaus. It is about 2000km long. The river course twists and turns. There are many sandbanks in the lower reaches. The river is 30-50km wide, like a long lake and below Taprukuala is navigable. Through the Negro River and the Casiquiare River, the Amazon River and Orinoco River are connected with each other.

The basin is hot, rainy and sparsely populated. The marshes along the coast are humus. The rainy season starts in September and ends in May. The water temperature is about 26.5-28℃. The dry season starts around May and ends from August to September. The water level drops and the temperature rises, and the water temperature is about 28.5-30°C. Due to the low water level in the dry season, the pH value in the dry season is about 3.4. The water body in dry season is “black water”, while the water color in rainy season is light yellow.

Underwater landscape

There are many dead leaves in the bottom bed of this tributary, and the increase of attachments makes the small fish have more food. Due to the existence of attachments, the bottom of the river is pale yellow. A large amount of humus darkens the color of water. The part near the river bank is much clearer, while the whole tributary is slightly turbid.

Fishes:

  • Hemigrammus rubrostriatus
  • Hemigrammus sp.
  • Hyphessorbrycon sp.

 

Threats to ecology

Manaus, as an important port of the Amazon River, is frequented by freighters, which also leads to a large number of fish moving their habitat to the depths of the jungle. Deep in the jungle, small fish can be seen everywhere, and abundant food resources give birth to many lives. It is also called the paradise for ornamental fish.

Riparian zone

Trees near the aquatic habitat
Few -