Recursos hídricos da região amazônica: utilização e preservação

Junk, Wolfgang J.

doi:10.1590/1809-43921979094s037

Cited by 13 publications

(9 citation statements)

References 1 publication

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“…Monitoring hydroelectric dam construction through detailed studies can reduce future negative effects (Junk, 1979). However, some tropical developing countries lack protocols to guide dam construction, even when environmental impact assessments are mandatory, and studies are sometimes completed after construction is in progress (Winemiller et al, 2016).…”

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confidence: 99%

Thirty years after Balbina Dam: Diversity and floristic composition of the downstream floodplain forest, Central Amazon, Brazil

et al. 2019

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The construction of hydroelectric dams causes changes in the diversity and floristic composition of floodplain forests due to the irregularity of the hydrological regime in rivers downstream from the dams. In the Amazon Basin, plans for the construction of dams are threatening the igapós, forests flooded by blackwater rivers. In these floodplains, the distribution of tree species is synchronized with periodic flood events of the topographic gradient. Previous studies on the Balbina Dam show an altered flood pulse downstream. This work discusses the potential long-term impacts on the diversity and floristic composition of an igapó downstream of the dam (Uatumã River) and compares it with an area unaffected by the dam (Abacate River). An evaluation of the vegetation strata-adults, saplings, and seedlings-showed that for all strata, diversity was greater in the high igapó (higher topographies) in the Uatumã area. This may be due to the near-total absence of flooding in the high igapó and to the extent of flooding in the low igapó (low topographies). Thus, in the Uatumã area, seeds of species typical of flooded areas cannot reach the high igapó by water and, thus, tend to be replaced by upland forest species (mainly seedlings). In the low igapó, the typical species have difficulty establishing. Therefore, the Uatumã vegetation forms two different communities, which does not occur in the Abacate area. These effects of the dam led to irreversible changes in the diversity and floristic composition across all strata throughout the entire topography in the downstream region.

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Thirty years after Balbina Dam: Diversity and floristic composition of the downstream floodplain forest, Central Amazon, Brazil

et al. 2019

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“…Its waters change from clear to white over the year, and there are several marginal areas that could act as a nursery for several fish species. As other oligotrophic rivers, the Negro River (Junk, 1979) has more productive tributaries that are unequally distributed along the river (Silva, 2011). Possibly the Demeni River can be considered one of these more productive tributaries, because the rivers of white waters are more fishy than those of black water.…”

Section: Resultsmentioning

confidence: 99%

Dynamics of Commercial Fishery at the Middle Stretch of the Negro River: Exploitation Intensity by Fishing Grounds

Lopes

Freitas

2019

Bol. Inst. Pesca

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In the middle Negro River, there have been several conflicts between the different fishing modalities due to the differential use of the fishing resource and the dispute over the same fishing areas. In this way, the spatial dynamics of commercial fishing in the municipality of Barcelos in the middle Negro River were analyzed, aiming to identify the locations used in the fisheries that may have different potentials and demand different actions. Information was collected from commercial fisher regarding the location of fishing sites and the frequency of use during high and low water periods. The geographic coordinates were identified with Q-Gis software and later submitted to a kernel-intensity technique. Eight fishing sites were used in commercial fisheries in Barcelos. In both hydrological periods, fishing occurred with a greater intensity in the Demeni River. Its waters change from light to white throughout the year, and there are several marginal areas that could serve as nurseries for various species of fish. Possibly, in this environment, there is a greater probability of conflicts occurring between the different resource users since this river is also exploited by recreational and subsistence fishers. This result shows that the spatial dynamics of fisheries can be truly important for management proposals.

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Section: Introductionmentioning

confidence: 99%

“…The Negro River stands out among the Amazon River's left bank tributaries due to being one of the three longest Amazonian black water rivers flowing for 1700 km with a mean discharge of 30.000 m 3 s -1 (SIOLI, 1968;JUNK, 1983). This river drains three main Amazonian geological formations such as the Guiana Shield and the Tertiary and Quaternary sediment regions (JUNK, 1983). The black water rivers are characterized by the dark brown color, produced by the allochthonous matter from the forest in decomposition (LEENHEER and SANTOS, 1980) or leached in podzolic and sandy soils along their courses (CHAAR, 1995).…”

Section: Introductionmentioning

confidence: 99%

“…The drainages of the east region have their origins in the Central Brazilian and Guianas Shields (GOULDING et al, 2003). The territorial dimension of the basin and the environmental factors such as relief, soil, climate, vegetation and biodiversity are primarily responsible for the remarkable differences in color of the waters and occurrence of different water types (FITTKAU, 1964;JUNK, 1983;STALLARD and EDMOND, 1983). Among the numerous works already done in the Amazonian basin, we highlight those relating to the origin of the acidity (pH 4.7 to 6.3) and dark color, which reflects the A contribution to the hydrochemistry and water typology of the Amazon River and its tributaries humic and fulvic substances content (LEENHER and SANTOS, 1980) and water geochemistry (DE PAULA, 1990).…”

Section: Introductionmentioning

confidence: 99%

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A Contribution to the Hydrochemistry and Water Typology of the Amazon River and Its Tributaries

Silva

Ríos‐Villamizar

Cunha

et al. 2019

RCG

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The geological diversity of the Amazon Basin, as well as the pluvial regime, influences the characteristics of the waters. To know the water types of the rivers of the Amazon basin, 288 superficial water samples were collected, 94 of them along the Amazon River and 194 in their tributaries, from March 2009 to September 2012. The physical, chemical, and physicochemical properties were analyzed. Rivers with pH between 6.5 and 7.6 and electrical conductivity (40.00 - 80.00 μS cm-1) are water bodies that are influenced by the Andean region (e.g., the Amazon River and some of its right bank tributaries). On the other hand, the rivers with pH in the range of 3.5 to 5.5 and conductivity <30.00 μS cm-1, which are Amazon River’s left bank tributaries, reflect the characteristics of the Guiana Shield. The rivers with pH (6.0 to 7.0), low ionic charge, and conductivity <40.0 μS cm-1, such as the lower Amazon River’s right bank tributaries (Tapajos and Xingu) which are influenced by the Central Brazilian Shield, and also the middle/upper Amazon River’s right bank tributaries (Tefé, Coari and Jutaí).

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Recursos hídricos da região amazônica: utilização e preservação

Cited by 13 publications

References 1 publication

Thirty years after Balbina Dam: Diversity and floristic composition of the downstream floodplain forest, Central Amazon, Brazil

Thirty years after Balbina Dam: Diversity and floristic composition of the downstream floodplain forest, Central Amazon, Brazil

Dynamics of Commercial Fishery at the Middle Stretch of the Negro River: Exploitation Intensity by Fishing Grounds

A Contribution to the Hydrochemistry and Water Typology of the Amazon River and Its Tributaries

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