scholarly journals MUDANÇAS AMBIENTAIS QUATERNÁRIAS NA PORÇÃO SUBMÉDIA DA PLANÍCIE DO SÃO FRANCISCO: RECONSTRUÇÃO AMBIENTAL

2017 ◽  
Vol 32 (3) ◽  
pp. 107
Author(s):  
Daniel Rodrigues de Lira
Keyword(s):  
General Circulation ◽  
Environmental Changes ◽  
Time Frame ◽  
Atmospheric Teleconnection ◽  
Sao Francisco River ◽  
River Floodplains ◽  
São Francisco River ◽  
Floodplain Deposits ◽  
The Last Glacial

A dinâmica dos acontecimentos geomorfológicos e sua evolução tornam-se necessárias para elucidar a história recente da paisagem. Nessa perspectiva a análise de depósitos superficiais permitiu a reconstrução das dinâmicas ambientais para a região com ênfase temporal/paleoambiental. Os Latossolos que integram a Planície do Rio São Francisco têm origem a partir do rebaixamento de suas águas e surgimento de barras arenosas retrabalhadas pelo vento em períodos de maior semiaridez formando campos de dunas; em períodos mais úmidos, mantos de areia, sendo estes retrabalhados em momentos de cheias, originando depósitos arenosos na planície fluvial. Os estudos indicam uma gênese climática controlada por fatores da circulação geral da atmosfera em nível global e regional, revelando tele conexões importantes desde o Último Máximo Glacial – UMG, transição Pleistoceno/Holoceno até o Holoceno Superior. QUATERNARY ENVIRONMENTAL CHANGES IN THE SUBMIDDLE REACH OF SÃO FRANCISCO RIVER FLOODPLAINS: AN ENVIRONMENTAL RECONSTRUCTION ABSTRACTThe analysis of superficial deposits allows the reconstruction the environmental dynamics of the study area within a given palaeo-environmental time frame. The Oxisols developed on the Sao Francisco floodplain deposits, originate from the lowering of water-table levels in the river banks and the subsequent emergence of sandy bars, some of which were reworked by wind erosion during periods of stronger semi-aridity, resulting in the accumulation of dune fields and sand mantles in wetter periods. Later on, some of these deposits were reworked by the floods of the São Francisco River. The results of this research point to a climatic genesis of landforms, driven by general circulation controls, thus revealing the role of important atmospheric teleconnection events in the area occurring since the Last Glacial Maximum – LGM, through the Pleistocene/Holocene transition until the Upper Holocene.Keywords: evolution of the landscape; superficial deposits; semiarid.

scholarly journals Cryptic species diversity in the Hypsolebias magnificus complex, a clade of endangered seasonal killifishes from the São Francisco River basin, Brazilian Caatinga (Cyprinodontiformes, Aplocheilidae)

ZooKeys ◽  
2018 ◽  
Vol 777 ◽  
pp. 141-158 ◽  
Author(s):  
Wilson J. E. M. Costa ◽  
Pedro F. Amorim ◽  
José Leonardo O. Mattos
Keyword(s):  
Cryptic Species ◽  
Environmental Changes ◽  
Molecular Data ◽  
Northeastern Brazil ◽  
Nominal Species ◽  
Test Species ◽  
Small Areas ◽  
Sao Francisco River ◽  
River Floodplains ◽  
São Francisco River

A great diversity of animal species adapted to life in the semi-arid Caatinga of northeastern Brazil, including seasonal killifishes, has been reported in the last three decades. More recently, field and molecular data have shown a high occurrence of cryptic species. The killifish group herein analysed, the Hypsolebiasmagnificus species complex, is endemic to the middle and southern portion of the Caatinga, occupying about 120 km along the floodplains of the middle São Francisco River and some adjacent tributaries. Species of this complex are rare and presently considered threatened with extinction, being uniquely found in pools protected by trees and bushes. Single-locus delimitation methods were used to test species limits of populations displaying different colour patterns along the whole distribution of the complex. All analyses consistently supported the three nominal species and two new, herein described: H.gardneri Costa, sp. n., from the floodplains of the middle São Francisco River and H.hamadryades Costa, sp. n., from the Gorotuba River floodplains. The phylogenetic analysis highly supports H.hamadryades as sister to a clade comprising H.gardneri and H.harmonicus. Our field observations suggest that H.hamadryades is a miniature species. This study indicates that the H.magnificus complex comprises cryptic species apparently endemic to small areas and extremely vulnerable to environmental changes, deserving high concern.

Challenge and response in the São Francisco River Basin

Water Policy ◽  
2014 ◽  
Vol 16 (S1) ◽  
pp. 153-200 ◽  
Author(s):  
Hannah Lee ◽  
Zamyla Chan ◽  
Kai Graylee ◽  
Arani Kajenthira ◽  
Daniela Martínez ◽  
...  
Keyword(s):  
Special Focus ◽  
Policy Debate ◽  
Management Framework ◽  
Sao Francisco River ◽  
São Francisco River ◽  
Depth Analysis ◽  
Major River ◽  
Set Up ◽  
Development And Management

The São Francisco River has been, and continues to be, the only major river in arid Northeast Brazil and, as such, continues to be a major focus for development policy in this poorest part of the country. In a context of persistent water scarcity and recurring drought, the imperative is to develop a water development and management framework capable of simultaneously creating a platform for growth, dealing with distributive conflicts and ensuring rational usage. Addressing this challenge has been complicated by the multi-layered institutions of Brazilian federalism. This paper traces the development of the institutional framework for water management in the São Francisco Basin, highlighting the role of both local innovation and the pressures of federal centralization. The single most important policy debate currently affecting the basin is an ambitious inter-basin transfer project that aims to provide secure water supply to major cities and irrigation projects in neighboring basins. The paper provides an in-depth analysis of the project, with a special focus on understanding the policy process underpinning the project. This analysis anchors the discussion in the difficult dilemmas currently faced by policymakers and gives some insights into the actual functioning of a complex and sometimes ambiguous institutional set-up.

scholarly journals Significant Baseflow Reduction in the Sao Francisco River Basin

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 2
Author(s):  
Murilo Cesar Lucas ◽  
Natalya Kublik ◽  
Dulce B. B. Rodrigues ◽  
Antonio A. Meira Neto ◽  
André Almagro ◽  
...  
Keyword(s):  
River Basin ◽  
Water Scarcity ◽  
Agricultural Land ◽  
Sao Francisco River ◽  
São Francisco River ◽  
Terrestrial Water ◽  
Long Term Trends ◽  
Storage Change

Water scarcity is a key challenge to global development. In Brazil, the Sao Francisco River Basin (SFB) has experienced water scarcity problems because of decreasing streamflow and increasing demands from multiple sectors. However, the drivers of decreased streamflow, particularly the potential role of the surface-groundwater interaction, have not yet been investigated. Here, we assess long-term trends in the streamflow and baseflow of the SFB during 1980–2015 and constrain the most likely drivers of observed decreases through a trend analysis of precipitation (P), evapotranspiration (ET), and terrestrial water storage change (TWS). We found that, on average, over 86% of the observed decrease in streamflow can be attributed to a significant decreasing baseflow trend along the SFR, with a spatial agreement between the decreased baseflow, increased ET, and irrigated agricultural land in the Middle SFB. We also noted a decreasing trend in TWS across the SFB exceeding –20 mm year−1. Overall, our findings indicate that decreasing groundwater contributions (i.e., baseflow) are providing the observed reduction in the total SFR flow. A lack of significant P trends and the strong TWS depletion indicate that a P variability only has likely not caused the observed baseflow reduction, in mainly the Middle and Sub-middle SFB. Therefore, groundwater and surface withdrawals may likely be a driver of baseflow reduction in some regions of the SFB.

scholarly journals Seasonal study of concentration of heavy metals in waters from lower São Francisco River basin, Brazil

2016 ◽  
Vol 76 (4) ◽  
pp. 967-974 ◽  
Author(s):  
A. M. Souza ◽  
A. M. Salviano ◽  
J. F. B. Melo ◽  
W. P. Felix ◽  
C. S. Belém ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Trace Elements ◽  
River Basin ◽  
Environmental Changes ◽  
Gradual Increase ◽  
The Other ◽  
Sao Francisco River ◽  
São Francisco River ◽  
Awareness Programs ◽  
Hydrographic Network

Abstract In this study we determined the concentration of metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in the water lower São Francisco River basin, to evaluate the influence of urbanization and industrialization on environmental changes in the water resource. All samples were analyzed using the IUPAC adapted method and processed in an atomic absorption spectrophotometer. The sampling stations located near the industrial areas were influenced by industrialization because they presented higher concentrations of Cd, Cr, Ni and Cu. The other sampled locations showed changes with regard the trace elements probably originating in the soil, like Fe, Zn and Pb. There was a gradual increase in the concentrations of metals, in general, in the period of highest rainfall of the hydrographic network. Overall, except for Zn and Mn, the trace elements exceeded the maximum allowed value established by national legislation (CONAMA). Lower São Francisco River basin has suffered interference from urbanization and industrialization, so awareness programs should be developed so as to control and lessen future problems.

Dwarf geckos and giant rivers: the role of the São Francisco River in the evolution of Lygodactylus klugei (Squamata: Gekkonidae) in the semi-arid Caatinga of north-eastern Brazil

2019 ◽  
Vol 129 (1) ◽  
pp. 88-98
Author(s):  
Flávia M Lanna ◽  
Marcelo Gehara ◽  
Fernanda P Werneck ◽  
Emanuel M Fonseca ◽  
Guarino R Colli ◽  
...  
Keyword(s):  
Gene Flow ◽  
Assignment Test ◽  
Nuclear Markers ◽  
Sao Francisco River ◽  
Eastern Brazil ◽  
São Francisco River ◽  
North Eastern ◽  
Multilocus Approach ◽  
Geomorphological Features

Abstract Species diversification can be strongly influenced by geomorphological features, such as mountains, valleys and rivers. Rivers can act as hard or soft barriers to gene flow depending on their size, speed of flow, historical dynamics and regional topographical characteristics. The São Francisco River (SFR) is the largest perennial river in the Caatinga biome in north-eastern Brazil and has been considered a barrier to gene flow and dispersal. Herein, we evaluated the role of the SFR on the evolution of Lygodactylus klugei, a small gecko from the Caatinga. Using a single-locus species delimitation method (generalized mixed Yule coalescent), we defined lineages (haploclades). Subsequently, we evaluated the role of the SFR in structuring genetic diversity in this species using a multilocus approach to quantify migration across margins. We also evaluated genetic structure based on nuclear markers, testing the number of populations found through an assignment test (STRUCTURE) across the species distribution. We recovered two mitochondrial lineages structured with respect to the SFR, but only a single population was inferred from nuclear markers. Given that we detected an influence of the SFR only on mitochondrial markers, we suggest that the current river course has acted as a relatively recent geographical barrier for L. klugei, for ~450 000 years.

scholarly journals Significant baseflow reduction in the Sao Francisco River Basin

2020 ◽  
Author(s):  
Murilo Cesar Lucas ◽  
Natalya Kublik ◽  
Dulce B. B. Rodrigues ◽  
Antonio A. Meira Neto ◽  
André Almagro ◽  
...  
Keyword(s):  
River Basin ◽  
Water Scarcity ◽  
Agricultural Land ◽  
Sao Francisco River ◽  
São Francisco River ◽  
Terrestrial Water ◽  
Long Term Trends ◽  
Storage Change

Water scarcity is a key challenge to global development. In Brazil, the Sao Francisco River Basin (SFB) has experienced water scarcity problems because of decreasing streamflow and increasing demands from multiple sectors. However, the drivers of decreased streamflow, particularly the potential role of surface-groundwater interaction, have not been yet investigated. Here, we assess long-term trends in baseflow, quickflow, and streamflow of the SFB during 1980–2015 and constrain the most likely drivers of observed decreases through trend analysis of precipitation (P), evapotranspiration (ET), and terrestrial water storage change (TWS). We found that over 82% of the observed decrease in streamflow can be attributed to a significant decreasing baseflow trend (< -20 m3 s-1 y-1) along the SFR with spatial agreement between decreased baseflow, increased ET, and irrigated agricultural land. We also noted a decrease in TWS across the SFB with trends exceeding -20 mm y-1. Overall, our findings indicate that decreasing groundwater contributions (i.e., baseflow) is providing the observed reduction in total SFR flow. A lack of significant P trends indicates that only P variability likely has not caused the observed baseflow reduction, mainly in the Middle and Sub-middle SFB. Therefore, groundwater and surface withdrawals may be likely a driver of water scarcity over the SFB.

Role of HSP70 in the regulation of the testicular apoptosis in a seasonal breeding teleostProchilodus argenteusfrom the São Francisco river, Brazil

2013 ◽  
Vol 76 (4) ◽  
pp. 350-356 ◽  
Author(s):  
Fabricio F.T. Domingos ◽  
Ralph G. Thomé ◽  
Patrícia M. Martinelli ◽  
Yoshimi Sato ◽  
Nilo Bazzoli ◽  
...  
Keyword(s):  
Seasonal Breeding ◽  
Sao Francisco River ◽  
São Francisco River

ON EVALUATION OF THE ROLE OF THERMAL AND WIND FACTORS FOR A PHYSICAL MODEL OF THE WORLD OCEAN GENERAL CIRCULATION SYSTEM

2019 ◽  
Vol 47 (3) ◽  
pp. 80-91
Author(s):  
V. G. Neiman
Keyword(s):  
Physical Model ◽  
Ocean Circulation ◽  
General Circulation ◽  
World Ocean ◽  
Circulation System ◽  
The Public ◽  
The World ◽  
Almost All ◽  
Conceptual Foundations

The main content of the work consists of certain systematization and addition of longexisting, but eventually deformed and partly lost qualitative ideas about the role of thermal and wind factors that determine the physical mechanism of the World Ocean’s General Circulation System (OGCS). It is noted that the conceptual foundations of the theory of the OGCS in one form or another are contained in the works of many well-known hydrophysicists of the last century, but the aggregate, logically coherent description of the key factors determining the physical model of the OGCS in the public literature is not so easy to find. An attempt is made to clarify and concretize some general ideas about the two key blocks that form the basis of an adequate physical model of the system of oceanic water masses motion in a climatic scale. Attention is drawn to the fact that when analyzing the OGCS it is necessary to take into account not only immediate but also indirect effects of thermal and wind factors on the ocean surface. In conclusion, it is noted that, in the end, by the uneven flow of heat to the surface of the ocean can be explained the nature of both external and almost all internal factors, in one way or another contributing to the excitation of the general, or climatic, ocean circulation.

scholarly journals Community structure of aquatic insects (Ephemeroptera, Plecoptera, and Trichoptera) in Cerrado streams of Paraguay, Paraná, and São Francisco river basins

2013 ◽  
Vol 13 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Renato de Mei Romero ◽  
Mônica Ceneviva-Bastos ◽  
Gustavo Henrique Baviera ◽  
Lilian Casatti
Keyword(s):  
Community Structure ◽  
Aquatic Insects ◽  
Regional Differences ◽  
River Basins ◽  
Taxonomic Composition ◽  
Taxonomic Resolution ◽  
Sao Francisco River ◽  
Original Distribution ◽  
São Francisco River

We evaluated qualitatively and quantitatively the community structure of aquatic insects (Ephemeroptera, Plecoptera, and Trichoptera) in 19 streams in areas of Cerrado in the Paraguay, Paraná, and São Francisco river basins. The number of genera and taxonomic composition were compared at spatial (at the hydrographic basins level) and conservation levels (more preserved and less preserved areas). The influence of spatial and environmental factors in richness and abundance was also evaluated. The geographical distribution of Grumicha, Coryphorus, and Austrotinodes was expanded. The highest Trichoptera richness was found in the São Francisco river basin (F = 5,602, p = 0,004) and a higher number of Ephemeroptera genera occurred in the relatively less preserved sites (F = 6,835, p = 0,009). The pattern of genera distribution was different among basins (R = 0,0336, p = 0,001), but it was similar among relatively less and more preserved areas (R = -0,039, p = 0,737). These findings can be explained by the low impact level in these streams and also by the taxonomic resolution used in this study. Latitude and instream diversity were the most important factors to explain the variation in genera richness and abundance (p = 0.004 and p = 0.026, respectively). Hence, the regional differences can be attributed to spatial influences, quantity or quality of habitats and the original distribution of taxa within each basin.

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