scholarly journals Simulation of Water Sources and Precipitation Recycling for the MacKenzie, Mississippi, and Amazon River Basins

2006 ◽  
Vol 7 (3) ◽  
pp. 312-329 ◽  
Author(s):  
Michael G. Bosilovich ◽  
Jiun-Dar Chern

Abstract An atmospheric general circulation model simulation for 1948–97 of the water budgets for the MacKenzie, Mississippi, and Amazon River basins is presented. In addition to the water budget, passive tracers are included to identify the geographic sources of water for the basins, and the analysis focuses on the mechanisms contributing to precipitation recycling in each basin. While each basin’s precipitation recycling has a strong dependency on evaporation during the mean annual cycle, the interannual variability of the recycling shows important relationships with the atmospheric circulation. The MacKenzie River basin recycling has only a weak interannual correspondence with evaporation, where the variations in zonal moisture transport from the Pacific Ocean can affect the basin water cycle. On the other hand, the Mississippi River basin precipitation and recycling have strong interannual correlation on evaporation. The evaporation is related to the moist and shallow planetary boundary layer that provides moisture for convection at the cloud base. At global scales, high precipitation recycling is also found to be partly correlated to warm SSTs in the tropical Pacific Ocean. The Amazon River basin evaporation exhibits small interannual variations, so the interannual variations of precipitation recycling are related to atmospheric moisture transport from the tropical South Atlantic Ocean. Increasing SSTs over the 50-yr period are causing increased easterly transport across the basin. As moisture transport increases, the Amazon precipitation recycling decreases (without real-time varying vegetation changes). In addition, precipitation recycling from a bulk diagnostic method is compared to the passive tracer method used in the analysis. While the mean values of the different recycling methods are different, the interannual variations are comparable between each method. The methods also exhibit similar relationships to the terms of the basin-scale water budgets.

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2012 ◽  
Vol 8 (3) ◽  
pp. 592 ◽  
Author(s):  
Fernando C. P. Dagosta ◽  
Murilo N. L. Pastana ◽  
André L. H. Esguícero

The first report of Sartor (Anostomidae) and Tatia intermedia (Auchenipteridae) for the Upper Tapajós River Basin are presented here. Sartor is very rare on collections, and is reported only from the Trombetas, Tocantins and Upper Xingu river basins. Tatia intermedia is registered in the upper reaches of the Araguaia, Tocantins, Xingu, and Capim rivers, tributaries of the lower Amazon River in Brazil, northwards to the Suriname coastal rivers and the Essequibo River in Guyana.


2005 ◽  
Vol 3 (1) ◽  
pp. 89-106 ◽  
Author(s):  
Carl J. Ferraris Jr. ◽  
Richard P. Vari ◽  
Sandra J. Raredon

The Neotropical auchenipterid catfish genus Auchenipterichthys is reviewed and found to include four species. Auchenipterichthys thoracatus, formerly considered to be widely distributed throughout the Amazon River basin, is found to be restricted to the upper Madeira River basin. The widespread Amazonian species that had been misidentified as A. thoracatus is, instead, A. coracoideus; a species that also occurs in the upper Essequibo River. Auchenipterichthys longimanus, the most widely distributed species of the genus, is found through much of the Amazon and Orinoco River basins. The fourth species of the genus, A. punctatus (and its junior synonym A. dantei), is found in the upper portions of the Orinoco and Negro River basins in Venezuela and the central portions of the Amazon River basin in Brazil. All four species of Auchenipterichthys are redescribed and illustrated, and a key to the species is provided.


2018 ◽  
Vol 22 (3) ◽  
pp. 1735-1748 ◽  
Author(s):  
Juan Fernando Salazar ◽  
Juan Camilo Villegas ◽  
Angela María Rendón ◽  
Estiven Rodríguez ◽  
Isabel Hoyos ◽  
...  

Abstract. Many natural and social phenomena depend on river flow regimes that are being altered by global change. Understanding the mechanisms behind such alterations is crucial for predicting river flow regimes in a changing environment. Here we introduce a novel physical interpretation of the scaling properties of river flows and show that it leads to a parsimonious characterization of the flow regime of any river basin. This allows river basins to be classified as regulated or unregulated, and to identify a critical threshold between these states. We applied this framework to the Amazon river basin and found both states among its main tributaries. Then we introduce the “forest reservoir” hypothesis to describe the natural capacity of river basins to regulate river flows through land–atmosphere interactions (mainly precipitation recycling) that depend strongly on the presence of forests. A critical implication is that forest loss can force the Amazonian river basins from regulated to unregulated states. Our results provide theoretical and applied foundations for predicting hydrological impacts of global change, including the detection of early-warning signals for critical transitions in river basins.


2014 ◽  
Vol 25 (1-2) ◽  
pp. 61-68 ◽  
Author(s):  
V. I. Monchenko ◽  
L. P. Gaponova ◽  
V. R. Alekseev

Crossbreeding experiments were used to estimate cryptic species in water bodies of Ukraine and Russia because the most useful criterion in species independence is reproductive isolation. The problem of cryptic species in the genus Eucyclops was examined using interpopulation crosses of populations collected from Baltic Sea basin (pond of Strelka river basin) and Black Sea basin (water-reservoires of Dnieper, Dniester and Danube rivers basins). The results of reciprocal crosses in Eucyclops serrulatus-group are shown that E. serrulatus from different populations but from water bodies belonging to the same river basin crossed each others successfully. The interpopulation crosses of E. serrulatus populations collected from different river basins (Dnipro, Danube and Dniester river basins) were sterile. In this group of experiments we assigned evidence of sterility to four categories: 1) incomplete copulation or absence of copulation; 2) nonviable eggs; 3) absence of egg membranes or egg sacs 4) empty egg membranes. These crossbreeding studies suggest the presence of cryptic species in the E. serrulatus inhabiting ecologically different populations in many parts of its range. The same crossbreeding experiments were carries out between Eucyclops serrulatus and morphological similar species – Eucyclops macruroides from Baltic and Black Sea basins. The reciprocal crossings between these two species were sterile. Thus taxonomic heterogeneity among species of genus Eucyclops lower in E. macruroides than in E. serrulatus. The interpopulation crosses of E. macruroides populations collected from distant part of range were fertile. These crossbreeding studies suggest that E. macruroides species complex was evaluated as more stable than E. serrulatus species complex.


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