Contrasted distributions of triterpene derivatives in the sediments of Lake Caçó reflect paleoenvironmental changes during the last 20,000 yrs in NE Brazil

Jacob, Jérémy; Disnar, Jean-Robert; Boussafir, Mohammed; Albuquerque, Ana Luíza Spadano; Sifeddine, Abdelfettah; Turcq, Bruno

doi:10.1016/j.orggeochem.2006.10.007

Cited by 80 publications

(54 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…3; Table 1 were indicative of a C-ring cleavage typical of oleanene and ursene structures, followed by retroDiels-Alder rearrangement (Djerassi et al, 1962). Based on mass spectral resemblance with published data (Corbet et al, 1980;Logan and Eglinton, 1994;Jacob et al, 2007) and on the relative retention times of ursene and oleanene-type Δ 12 and Δ 13,18 isomers, we tentatively assigned compound DA1 as des-A-olean-13(18)-ene, DA2 as Des-A-olean-12-ene and DA3 as des-A-urs-12-ene. DA4 was assigned as des-A-lupane from comparison with published mass spectra (Corbet et al, 1980;Philp, 1985).…”

Section: Biomarker Identificationmentioning

confidence: 84%

“…Pentacyclic triterpenes with a lupane, oleanane or ursane structure, as well as their diagenetic derivatives, such as des-A-triterpanes, found in soils and sediments are classically used as tracers of angiosperms (Cranwell, 1984;Logan and Eglinton, 1994;Peters et al, 2005;Jacob et al, 2007). When functional groups are preserved, pentacyclic triterpenes allow a more precise distinction of their source organisms: at the family, genus or even species level (Jacob et al, 2005;Zocatelli et al, 2010;Lavrieux et al, 2011;Le Milbeau et al, 2013).…”

Section: Origin Of Biomarkersmentioning

confidence: 99%

See 1 more Smart Citation

High frequency floral changes at the Paleocene–Eocene boundary revealed by comparative biomarker and palynological studies

Garel

Quesnel

Jacob

et al. 2014

Organic Geochemistry

Self Cite

View full text Add to dashboard Cite

The Cap d'Ailly area (Upper Normandy, France) shows several terrestrial-lagoonal sections recording the negative Carbon Isotope Excursion (CIE) associated with the Paleocene-Eocene Thermal Maximum (PETM; 55.8 Ma). A study of the biomarkers and spores/pollen content of the Vasterival section gave complementary information on paleofloral changes that occurred around the PaleoceneEocene (P-E) boundary. Aliphatic hydrocarbon fractions revealed a high abundance of vascular plant biomarkers, including tricyclic diterpanes derived from conifers, fernenes derived from ferns and des-A-triterpenes derived from angiosperms. Whereas the vegetation of the depositional environment surroundings seemed alternately dominated by ferns and angiosperms (as revealed by biomarkers), the regional flora seemed strictly dominated by angiosperms such as Juglandaceae (as revealed by pollen).Spores/pollen assemblages reveal no major turnover in the paleovegetation, but slight variation in vegetation composition. However, both biomarkers and spores/pollen exhibited two intervals of rapid floral changes: the first occurred around the P-E boundary and the second at the top of the strictly terrestrial unit that coincides with a marine transgression. Comparison of these data with published paleoclimatic results, obtained from the same samples, indicated that the first interval of floral change was correlated with strong paleohydrological perturbations, whereas the second was linked to an increasing marine influence.

show abstract

Section: Biomarker Identificationmentioning

confidence: 84%

Section: Origin Of Biomarkersmentioning

confidence: 99%

High frequency floral changes at the Paleocene–Eocene boundary revealed by comparative biomarker and palynological studies

Garel

Quesnel

Jacob

et al. 2014

Organic Geochemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…The head capsules of their exuviae frequently remain in the sediment if there are adequate conditions for preservation. The taxonomic identification of these structures in the sediment cores of the lake and its comparison with recent chironomid species can be of relevance for reconstruction of paleoenvironmental conditions Quinlan and Smol (2001), since sediment cores of Lake Caçó were collected (Jacob et al, 2007a;Jacob et al, 2007b).…”

Section: Mean Density Precipitationmentioning

confidence: 99%

Benthic macroinvertebrates of a tropical lake: Lake Caçó, MA, Brazil

et al. 2010

View full text Add to dashboard Cite

Benthic communities are highly relevant in the study of aquatic ecosystems, both for their role in the functioning of the ecosystem and also as markers or indicators of paleo-conditions. Their distribution, as in other communities, is conditioned by abiotic and biotic factors and to their interactions, which determine the structure of the community that is established. The aim of this study was to determine the taxonomic composition, abundance and spatial distribution of the benthic community, by collecting at 20 sampling sites in Caçó Lake (State of Maranhão, Brazil). Seasonal variation in these community parameters was analysed and related to the seasonal displacement of the Intertropical Convergence Zone. The results indicated that changes occur in the taxa richness, diversity and density of the benthic species of this lake that are mainly related to seasonality. All those parameters were higher in the dry than in the rainy period. The family Chironomidae (Diptera, Insecta) was the most important component of the community, representing approximately 50% of the total benthic fauna of the lake. The identification of the Chironomidae currently occurring in Lake Caçó is relevant, even at the genus level, considering the fact that this group produces fossilizing remains and could perhaps be good paleolimnological and paleoclimatic tracers that could be used to make inferences on past lake and climate conditions. Keywords: benthic community, Chironomidae, Lake Caçó, tropical Limnology, macroinvertebrates. Macroinvertebrados bentônicos de um lago tropical: lago Caço, MA, Brasil ResumoAs comunidades bentônicas são relevantes nos ecossistemas aquáticos devido ao seu papel no seu funcionamento e também como marcadores ou indicadores de paleocondições. Sua distribuição, similarmente à de outras comunidades, é condicionada por fatores abióticos e bióticos e pela interação entre eles, determinando a estrutura da comunidade que se estabelecerá. O objetivo do presente trabalho foi determinar a composição taxonômica, a abundância e a distribuição espacial da comunidade bentônica, amostrando-se em 20 pontos na lagoa do Caçó (Estado do Maranhão, Brasil). As variações sazonais nas características desta comunidade foram analisadas e relacionadas ao deslocamento sazonal da Zona de Convergência Intertropical. Os resultados indicaram que ocorrem mudanças na riqueza de taxons, diversidade e densidade da comunidade bentônica deste lago que são principalmente relacionadas à sazonalidade. Todas as variáveis analisadas foram maiores no período seco do que no chuvoso. Os organismos pertencentes à família Chironomidae (Diptera, Insecta) foram os mais importantes componentes da comunidade, representando aproximadamente 50% do total da fauna. A identificação dos Chironomidae atualmente presentes no Lago Caçó, mesmo em nível de gênero, é relevante, considerando-se o fato de que as larvas deste grupo produzem remanescentes fósseis que podem ser bons traçadores paleolimnológicos e paleoclimáticos, podendo ser utilizados para fazer inf...

show abstract

“…I nt r oduct i on L ipid biomar ker s const it ut e efficient t ools for t r acing t he sources of organic mat t er (OM) in mar ine (H ar ada et al, 1995;Aquilina et al, 2010), fluvial (Jaffé et al, 1995;H emingway et al, 2016) or lacust r ine envir onment s (Rieley et al, 1991;Jacob et al, 2007).…”

mentioning

confidence: 99%