Changes in organic matter from surface waters to continental slope sediments off the São Francisco River, eastern Brazil

1999 ◽  
Vol 161 (2-4) ◽  
pp. 129-140 ◽  
Author(s):  
Tim C Jennerjahn ◽  
Venugopalan Ittekkot
Keyword(s):  
Organic Matter ◽  
Continental Slope ◽  
Surface Waters ◽  
Sao Francisco River ◽  
Eastern Brazil ◽  
São Francisco River

Organic matter in the deltaic clinoform of the São Francisco River (Eastern Brazil)

2019 ◽  
Vol 40 (6) ◽  
pp. 879-895 ◽  
Author(s):  
Narayana Flora Costa Escobar ◽  
José Maria Landim Dominguez ◽  
Maria do Rosário Zucchi ◽  
Antônio Expedito Gomes de Azevedo ◽  
Adriane Gonçalves de Araújo Nunes Rangel ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sao Francisco River ◽  
Eastern Brazil ◽  
São Francisco River

scholarly journals Monsoonal forcing controlled cold water coral growth off south-eastern Brazil during the past 160 kyrs

2020 ◽  
Author(s):  
André Bahr ◽  
Monika Doubrawa ◽  
Jürgen Titschack ◽  
Gregor Austermann ◽  
Dirk Nürnberg ◽  
...  
Keyword(s):  
Organic Matter ◽  
Continental Slope ◽  
Deep Water ◽  
Cold Water ◽  
Nepheloid Layer ◽  
High Northern Latitude ◽  
South Eastern ◽  
The Past ◽  
Eastern Brazil ◽  
Water Ecosystems

Abstract. Cold-water corals (CWC) constitute important deep-water ecosystems that are increasingly under environmental pressure due to ocean acidification and global warming. The sensitivity of these deep-water ecosystems to environmental change is demonstrated by abundant paleo-records drilled through CWC mounds that reveal a characteristic alteration between rapid formation and dormant or erosive phases. Previous studies have identified several parameters such as food supply, oxygenation, and carbon saturation state of bottom water as central for driving or inhibiting CWC growth, yet there is still a large uncertainty about the relative importance of the different environmental parameters. To advance this debate we have performed a multi-proxy study on a sediment core retrieved from the 25 m high Bowie Mound, located in 866 m water depth on the continental slope off south-eastern Brazil, a structure built up mainly by the CWC Solenosmilia variabilis. Our results indicate a multi-factorial control on CWC growth and mound formation at Bowie Mound during the past ~160 kyrs, which reveals distinct formation pulses during glacial high northern latitude cold events (Heinrich Stadials, HS) largely associated with anomalous continental wet periods. The ensuing enhanced run-off elevated the terrigenous nutrient and organic matter supply to the continental margin, and might have boosted marine productivity. The dispersal of food particles towards the CWC colonies during HS was facilitated by the highly dynamic hydraulic conditions along the continental slope that prevailed throughout glacial periods. These conditions caused the emplacement of a pronounced nepheloid layer above Bowie Mound aiding the concentration and along-slope dispersal of organic matter. Our study thus demonstrates a yet unrecognized impact of continental climate variability on a highly vulnerable deep-marine ecosystem.

Is the São Francisco River a geographic barrier to gene flow in trees of Handroanthus ochraceus?

2013 ◽  
Vol 29 (3) ◽  
pp. 243-250 ◽  
Author(s):  
Patrícia de Abreu Moreira ◽  
G. Wilson Fernandes
Keyword(s):  
Gene Flow ◽  
Genetic Relatedness ◽  
Left Bank ◽  
Geographic Barrier ◽  
Sao Francisco River ◽  
Seasonally Dry ◽  
Eastern Brazil ◽  
São Francisco River ◽  
The Right ◽  
Two Populations

Abstract:Many landscape features represent geographic barriers to gene flow, and promote genetic discontinuity. Rivers are effective barriers. However, most studies on this subject have focused on animals and only a few have focused on plants. We studied the genetic structure and gene flow of the tropical tree Handroanthus ochraceus (Bignoniaceae) on both banks of the São Francisco River in a Brazilian seasonally dry tropical forest. The São Francisco is located in eastern Brazil and is 600 m wide at the study site. Our hypothesis was that the river is a geographic barrier to gene flow of H. ochraceus trees. We sampled two populations on the left bank and one population on the right bank. We used seven microsatellites to genotype 212 individual plants. All populations had low polymorphism and genetic diversity, but high inbreeding. There was no genetic differentiation among populations and, consequently, the estimated gene flow was high for all pairs of populations. The genetic relatedness among individuals from populations of the same margin did not differ from the relatedness among individuals from populations of opposite margins. Hence, the São Francisco River is not an effective geographic barrier to gene flow among H. ochraceus populations.

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 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.

Candomblé e Cinema de Animação: Estratégias de resistência e territorialidade

2021 ◽  
Author(s):  
Pâmela Peregrino ◽  
Edileuza Penha de Souza
Keyword(s):  
Poetic Language ◽  
Public Places ◽  
Sao Francisco River ◽  
The People ◽  
São Francisco River ◽  
Popular Knowledge ◽  
Stop Motion ◽  
Short Movie

The majority of the knowledge and philosophy of African roots find a great discrimination in public places in Brazil, rarely we see schools take in consideration those questions, popular knowledge and ways of living of those who follow those religions of African roots. Take in account that reality and seeking for changing it, the members of Abassá of goddess Òsùn of Idjemim, Paulo Afonso - BA, Bahia took the initiative of producing an animated stop motion movie about the Òrìṣà Òsùn. In this short motion “Òpárà de Òsùn: when everything is born” (2018) we can see the language of animation cinema being used to tell stories of Òrìṣàs like of a way clamouring the religiosity from people from traditional places and also a way of facing religious racism. In this work, we will present the process of production of a short motion, that took in consideration the bio system Caatinga and of the Sao Francisco river as a scenery of some events, staring from the sonorities and images produced by the people in the Terreiro and including the poetic language (could it be sounding and visual or spoken). From those elements, we reflect about the role played by this short movie on the empowerment of children and territorially as didactic and educative space.

scholarly journals Mayfly diversity in the brazilian tropical headwaters of Serra do Cipó

2005 ◽  
Vol 48 (6) ◽  
pp. 983-996 ◽  
Author(s):  
Michael Goulart ◽  
Marcos Callisto
Keyword(s):  
Taxonomic Richness ◽  
Dry Period ◽  
Lotic Ecosystems ◽  
River Watershed ◽  
Rainy Period ◽  
Sao Francisco River ◽  
Serra Do Cipó ◽  
São Francisco River ◽  
Dry Seasons ◽  
Doce River

The objectives of this study were to evaluate spatial and seasonal distribution, assemblage structure and substrate associations of mayfly nymphs in five lotic ecosystems in the headwaters of the Doce River and São Francisco River watersheds, Brazil. Samples were taken in 24 sampling stations during rainy and dry seasons in 1998. In total, 7,066 organisms were collected, belonging to 27 genera and 6 families of Ephemeroptera. The dominant taxa were Americabaetis, Paracloeodes, Leptohyphes and Hagenulus. During the rainy period, the São Francisco River watershed showed higher taxonomic richness, diversity and evenness, while in the dry period, the taxonomic richness was higher in Doce River watershed. No significant differences were found in the taxonomic richness, diversity, evenness and density of mayfly assemblages between the two studied sampling periods. The results suggested that the diversity of the mayfly assemblages in tropical headwaters of Serra do Cipó would be probably due to ecosystem and watershed characteristics.

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