Suspended sediment in the Amazon River and its tributaries in Brazil during 1982-84
1985; United States Department of the Interior; Linguagem: Inglês
10.3133/ofr85492
ISSN2332-4899
Autores Tópico(s)Fish biology, ecology, and behavior
ResumoSuspended sediment was collected during 1982-84 from the Rio Solimoes-Amazonas (Amazon River) and its major tributaries on eight downriver sampling cruises between Rio lea and the town of Obidos, Brazil, and more frequently at a fixed time-series station near the city of Manaus.About 180 discharge-weighted composite samples were collected from 34 cross sections by depth-integrated sampling, using the equal-width-increment (equal-transit-rate) method.Suspended sand was sieved from each composite sample in the field, weighed in the laboratory, and analyzed for particle size by wet sieving.Concentrations of suspended silt and clay were determined by filtering representative subsamples of each cross-section composite.Concentrations of suspended sediment decreased down the Rio Solimoes-Amazonas ma ins tern.Concentrations in the mainstem during wet season were only 2 to 4 times those during dry season.The annual cycle of suspended-sediment concentration is markedly out of phase with the annual cycle of water discharge; graphed relations of sediment discharge versus water discharge form clockwise loops rather than straight lines or simple curves.Sampling errors were within +. 10 percent for total suspended sediment and within +_ 20 percent for suspended sands.Errors involved in field processing and laboratory analysis were smaller than the sampling errors.Data are presented in tables in sufficient detail and with sufficient supportive description that they may serve as baseline information for the assessment of the effects of future changes in the Amazon basin.
Referência(s)