The flooded Amazonian rainforest - Rio Negro Igapó, Brazil


Igapó is a word used in Brazil for blackwater-flooded Amazonian forests. These forests are seasonally inundated with freshwater. They typically occur along the lower reaches of rivers and around freshwater lakes. Igapó is primarily characterized by seasonal inundation caused by abundant rainfall; in some areas, trees can be submerged for up to 6 months of the year. These forests may be able to sustain a large amount of bird, mammal, reptile, amphibian, fish and invertebrate species, however, biodiversity varies between wetland ecosystems and the species richness of the freshwater swamp forests is not entirely known.
Igapó forests are characterized by sandy acidic soils that have a low nutrient content. The color and acidity of the water is due to the acidic organic humic substances (e.g. tannins) that dissolve into the water. The acidity from the water translates into acidic soils. Igapó and other flooded forests typically display a lower diversity of plants than that seen in terra firme forests. Similar to other forests found throughout the tropics, it is common to observe only a few dominant tree species. Distribution of trees and other plants is highly dependent on inundation tolerances of species causing a non-random distribution of plants where more flood-tolerant species are found at lower elevations and less flood-tolerant species are found on higher ground.
Tree species adapted to seasonal inundation have adapted to maximize fruit production during periods of flooding in order to take advantage of newly available seed dispersal methods. Fish consume nearly all fruit that fall into the water, and species that are unable to digest the seeds eventually excrete and disperse them into the water. Dispersal by other vectors such as birds and monkeys is secondary to that of fishes in igapó. An important factor in seed survival is the presence of seed predators. Fishes that lack the strong jaws found in characins, such as catfish, digest the fleshy material of the fruit while the seeds pass through the gut unharmed. Because many catfishes are bottom-feeders, they are critical dispersers for seeds that sink upon entering the water.

Freshwater Ecoregion of the World : #314 Rio Negro
Major Habitat Type: tropical and subtropical floodplain rivers and wetland complexes

Underwater photographs


U05-001 Black caiman

U05-002 Black caiman

U05-003 Black caiman

U05-004 Black caiman

U05-005 Black caiman

U05-006 Black caiman

U05-007 Black caiman


U05-008 Black caiman


U05-009 Black caiman

U05-010 Black caiman

U05-011 Black caiman

U05-012 Black caiman

U05-013 Black caiman

U05-014 Amazon river dolphin

U05-015 Amazon river dolphin

U05-016 Amazon river dolphin

U05-017 Amazon river dolphin

U05-018 Amazon river dolphin

U05-019 Amazon river dolphin

U05-020 Matrincha (Brycon sp.)

U05-021 Matrincha (Brycon sp.)

U05-022 Matrincha (Brycon sp.)

U05-023 Matrincha (Brycon sp.)

U05-024 Pseudoplatystoma fasciatum

U05-025 Semaprochilodus sp.

U05-026 Myleus sp.?

U05-027 Flooded forest

U05-028 Matrincha (Brycon sp.)

U05-029 Matrincha (Brycon sp.)

U05-030 Matrincha (Brycon sp.)

U05-031 Matrincha (Brycon sp.)

U05-032 Matrincha (Brycon sp.)

U05-033 Matrincha (Brycon sp.)

U05-034 Matrincha (Brycon sp.)

U05-035 Hemiodopsis sp.

U05-036 Geophagus sp.

U05-037 Crenicichla sp.

U05-038 Matrincha (Brycon sp.)

U05-039 Matrincha (Brycon sp.)

U05-040 Matrincha (Brycon sp.)

U05-041 Matrincha (Brycon sp.)

U05-042 Matrincha (Brycon sp.)

U05-043 Matrincha (Brycon sp.)

U05-044 Matrincha (Brycon sp.)

U05-045 Mesonauta sp.

U05-046 Matrincha (Brycon sp.)

U05-047 Mesonauta sp.

U05-048 Matrincha (Brycon sp.)

U05-049 Matrincha (Brycon sp.)

U05-050 Matrincha (Brycon sp.)


U05-051 Flooded forest


U05-052 Mesonauta sp.


U05-053 Mesonauta sp.


U05-054 Flooded forest


U05-055 Cichla temensis

U05-056 Cichla temensis

U05-057 Matrincha (Brycon sp.)

U05-058 Flooded forest

U05-059 Cichla temensis et al.

U05-060 Cichla temensis et al.

U05-061 Matrincha (Brycon sp.)

U05-062 Cichla temensis

U05-063 Flooded forest

U05-064 Flooded forest

U05-065 Cichla temensis et al.

U05-066 Cichla temensis

U05-067 Cichla temensis

U05-068 Matrincha (Brycon sp.)

U05-069 Cichla temensis

U05-070 Cichla temensis et al.

U05-071 Cichla temensis et al.


U05-072 Matrincha (Brycon sp.)


U05-073 Matrincha (Brycon sp.)

U05-074 Anostomus taeniatus

U05-075 Cichla temensis et al.

U05-076 Cichla temensis et al.

U05-077 Cichla temensis et al.

U05-078 Cichla temensis et al.

U05-079 Cichla temensis et al.

U05-080 Cichla temensis et al.

U05-081 Cichla temensis et al.

U05-082 Cichla temensis et al.

U05-083 Cichla temensis et al.

U05-084 Cichla temensis et al.

Aerial and landscape photographs


U05-501 Archipelago Anavilhanas

U05-502 Archipelago Anavilhanas

U05-503 Archipelago Anavilhanas

U05-504 Archipelago Anavilhanas

U05-505 Archipelago Anavilhanas

U05-506 Archipelago Anavilhanas

U05-507 Archipelago Anavilhanas

U05-508 Archipelago Anavilhanas

U05-509 Archipelago Anavilhanas

U05-510 Archipelago Anavilhanas

U05-511 Archipelago Anavilhanas

U05-512 Archipelago Anavilhanas

U05-513 Archipelago Anavilhanas

U05-514 Archipelago Anavilhanas

U05-517 Amazon river dolphin

U05-519 Amazon river dolphin

U05-518 Amazon river dolphin

U05-520 Amazon river dolphin

U05-515 Amazon river dolphin

U05-516 Amazon river dolphin

U05-521 Rio Negro tributary

U05-547 Rio Negro tributary

U05-546 Rio Negro tributary

U05-522 Black caiman

U05-523 Black caiman

U05-544 Black caiman

U05-545 Black caiman

U05-524 Rain on Rio Negro tributary

U05-525 Rio Negro tributary

U05-526 In the flooded forest

U05-527 In the flooded forest

U05-528 In the flooded forest

U05-529 In the flooded forest

U05-530 In the flooded forest

U05-531 In the flooded forest

U05-532 In the flooded forest

U05-533 In the flooded forest

U05-550 In the flooded forest

U05-551 In the flooded forest

U05-552 In the flooded forest

U05-534 In the flooded forest

U05-535 In the flooded forest

U05-536 In the flooded forest

U05-537 In the flooded forest

U05-538 In the flooded forest

U05-539 In the flooded forest

R-101 Roggo in the flooded forest

U05-540 Entering the flooded forest

U05-541 Entering the flooded forest

U05-542 Entering the flooded forest

U05-543 Entering the flooded forest

U05-548 Clouds over Amazon

U05-549 Clouds over Amazon

U05-553 Clouds over Amazon

U05-554 Clouds over Amazon

U05-555 Clouds over Amazon

U05-556 Clouds over Amazon


U05-557 Clouds over Amazon


U05-558 Clouds over Amazon river

U05-559 Clouds over Amazon river

U05-560 Clouds over Amazon river

U05-561 Clouds over Amazon river

U05-562 Clouds over Amazon river

U05-563 Clouds over Amazon river

U05-564 Clouds over Rio Branco

U05-565 Clouds over Rio Branco

U05-566 Clouds over Rio Branco

U05-567 Clouds over Rio Branco

U05-568 Rio Branco

U05-569 Rio Branco

U05-570 Rio Branco

U05-571 Rio Branco

U05-572 Rio Branco tributary

U05-573 Indian village

U05-574 Indian village

U05-575 Road in rainforest

U05-576 Road in rainforest

U05-577 Manaus

U05-578 Lodge in Rainforest
All Photographs Copyright 2013© Michel Roggo