Seismic stratigraphy of a partially filled incised valley on a semi-arid continental shelf, Northeast Brazil

2021 ◽  
Vol 41 (2) ◽  
Author(s):  
Antonio Rodrigues Ximenes Neto ◽  
Paulo Roberto Silva Pessoa ◽  
Lidriana de Souza Pinheiro ◽  
Jáder Onofre de Morais
2006 ◽  
Vol 54 (4) ◽  
pp. 173-181 ◽  
Author(s):  
Hortência Maria Pereira Araujo

The spatial and seasonal distribution of the Paracalanidae species were studied in eighteen stations in the continental shelf off Sergipe and Alagoas States, northeast Brazil, in December, 2001 and 2003, and in June, 2002 and 2003. The Paracalanidae family was constituted by coastal and shelf species such as Parvocalanus crassirostris, Paracalanus quasimodo, P. indicus and P. aculeatus and oceanic species, Calocalanus pavo and Acrocalanus longicornis. Density values were higher in stations located at 10 m isobath with respect to those located at 20 and 30 m depths. Paracalanidae abundance presented differences between seasons with values higher in June (2002, 2003) than in December (2001, 2002). All species were more abundant in the rainy season except Parvocalanus crassirostris. Paracalanus quasimodo was the dominant species with average densities of 949, 740 and 41 ind.m-3 in December months and 4231, 2389 and 1185 ind.m-3 in June months, at stations with local depths of 10, 20 and 30 m, respectively. Canonical correspondence analysis showed that salinity and temperature were the environmental variables that presented significant correlation with the distribution of Paracalanidae species, probably because these variables are influenced by the estuarine waters and by the dynamic of oceanic water masses in the continental shelf.


Author(s):  
Ivanilson de Souza Maia ◽  
Dárlio Inácio Alves Teixeira ◽  
Vigínia Maria Cavalari Henriques ◽  
Maulori Curié Cabral

Author(s):  
Raquel Barbosa da Silva ◽  
Edvaldo Vieira Silva‐Júnior ◽  
Larissa Maria Barreto de Medeiros Trigueiros ◽  
Rayza Helen Graciano dos Santos ◽  
Jailane de Souza Aquino ◽  
...  

2000 ◽  
Vol 55 (9-10) ◽  
pp. 688-692 ◽  
Author(s):  
Antonio F. M. Oliveira ◽  
Antonio Salatino

Abstract The epicuticular waxes of leaves of four species (Aspidospermci pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) from the Caatinga, (a semi-arid ecosystem of Northeast Brazil) and four species (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina and Tocoyena formosa) from the Cerrado, (a savanna ecosystem covering one third of the Brazilian territory), were analyzed. Six species contained a high content (above 60 μg.cm-2) of wax, four of them from the Caatinga. Triterpenoids and n-alkanes were the most frequent and abundant constituents found in the species from both habitats. The distribution of n-alkanes predominated by homologues with 27, 29, 31 and 33 carbon atoms, displayed no consistent differences between species from the two habitats. Lupeol, β-amyrin, epifriedelinol and ursolic acid were the triterpenoids found. Triterpenoids clearly predominate over alkanes in the waxes from the Cerrado species. The waxes of two evergreen species from the Caatinga yielded n-alkanes as predominant constituents. A comparison of foliar epicuticular waxes of native plants from ecosystems with different hydric constraints is discussed.


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