SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Dalibard, Mathieu; Popescu, Speranta-maria; Maley, Jean; Baudin, Francois; Melinte-dobrinescu, Mihaela-carmen; Pittet, Bernard; Marsset, Tania; Dennielou, Bernard; Droz, Laurence; Suc, Jean-pierre.

The essential characteristics of the vegetation dynamics of tropical Africa remain only partially known. This study assesses the succession of vegetation-types over Central Africa during the last two glacial/interglacial cycles. Analysis of core KZai 02, which contains pollen from the Zaire River watershed (latitudes 9°N-13°S), allows the investigation of long-term patterns of plant ecosystem development and their climatic causes. Core KZai 02 (18.20 m long) was recovered from 6°24.20′S/9°54.10′E in the uppermost axial edifice of the Zaire deep sea fan. The chronology of this sedimentary archive was established using nannofossils and correlations of pollen and total organic carbon signals with the nearby core GeoB1008. The pollen record indicates that: (i)...

Tipo: Text

Palavras-chave: Central Africa; Climate; Environmental parameters; Late Pleistocene; Pollen; Vegetation dynamics.

Ano: 2014

URL: http://archimer.ifremer.fr/doc/00199/31031/29436.pdf

The Ponto-Caspian basin as a final trap for southeastern Scandinavian Ice-Sheet meltwater

Middle to Late Pleistocene vegetation and climate change in subtropical southern East Africa

Tudryn, Alina; Leroy, Suzanne A. G.; Toucanne, Samuel; Gibert-brunet, Elisabeth; Tucholka, Piotr; Lavrushin, Yuri A.; Dufaure, Olivier; Miska, Serge; Bayon, Germain.

This paper provides new data on the evolution of the Caspian Sea and Black Sea from the Last Glacial Maximum until ca. 12 cal kyr BP. We present new analyses (clay mineralogy, grain-size, Nd isotopes and pollen) applied to sediments from the river terraces in the lower Volga, from the middle Caspian Sea and from the western part of the Black Sea. The results show that during the last deglaciation, the Ponto-Caspian basin collected meltwater and fine-grained sediment from the southern margin of the Scandinavian Ice Sheet (SIS) via the Dniepr and Volga Rivers. It induced the deposition of characteristic red-brownish/chocolate-coloured illite-rich sediments (Red Layers in the Black Sea and Chocolate Clays in the Caspian Sea) that originated from the Baltic...

Tipo: Text

Palavras-chave: Caspian sea; Black sea; SIS deglaciation; Early Khvalynian transgression; Chocolate clays; Red layers; Clay minerals; Neodymium isotopes; Pollen; Late Pleistocene.

Ano: 2016

URL: http://archimer.ifremer.fr/doc/00345/45605/45225.pdf

Palynological investigation of Holocene climatic and oceanic variability in South Africa and the southern Benguela upwelling system

Castaneda, Isla S.; Caley, Thibaut; Dupont, Lydie; Kim, Jung-hyun; Malaize, Bruno; Schouten, Stefan.

In this study we investigate Pleistocene vegetation and climate change in southern East Africa by examining plant leaf waxes in a marine sediment core that receives terrestrial runoff from the Limpopo River. The plant leaf wax records are compared to a multi-proxy sea surface temperature (SST) record and pollen assemblage data from the same site. We find that Indian Ocean SST variability, driven by high-latitude obliquity, exerted a strong control on the vegetation of southern East Africa during the past 800,000 yr. Interglacial periods were characterized by relatively wetter and warmer conditions, increased contributions of C3 vegetation, and higher SST, whereas glacial periods were marked by cooler and arid conditions, increased contributions of C4...

Tipo: Text

Palavras-chave: Vegetation; Africa; N-alkane; Pollen; Subtropical Front; Mid-Brunhes.

Ano: 2016

URL: https://archimer.ifremer.fr/doc/00345/45601/45215.pdf

Contrasting intrainterstadial climatic evolution between high and middle North Atlantic latitudes: A close-up of Greenland Interstadials 8 and 12

Zhao, Xueqin.

South Africa is very sensitive to climate change, because it is located between two atmospheric systems (subtropical and warm-temperate systems) and two oceanic systems (Benguela Current and Agulhas Current). Presently, the seasonal changes of atmospheric and oceanic systems induce a pronounced rainfall seasonality comprised of three different rainfall zones (summer rainfall zone, SRZ; year-round rainfall zone, YRZ and winter rainfall zone, WRZ) over South Africa. However, the seasonality development during the Holocene in South Africa is poorly understood and the driving forces of the climate change are debated. Therefore, this study aims to provide a detailed reconstruction of Holocene climate and vegetation variability of South Africa,...

Tipo: Text

Palavras-chave: Holocene; Marine sediments; Pollen; Microcharcoal; Organic-walled dinoflagellate cyst; Paleoenvironment; Paleoceanography; South Africa.

Ano: 2017

URL: https://archimer.ifremer.fr/doc/00493/60442/63887.pdf

Sanchez Goni, Maria Fernanda; Landais, Amaelle; Cacho, Isabel; Duprat, Josette; Rossignol, Linda.

Three highly resolved pollen and sea surface temperature records from the Iberian margin (36-42 degrees N) reveal the local evolution of vegetation and climate associated with the rapid climatic variability of marine isotope stage 3. The comparison of the climate at these midlatitudes with delta D and d excess from Greenland ice cores shows that the north-south climatic gradient underwent strong variations during the long Greenland Interstadials (GIs) 8 and 12. After the Northern Hemispheric rapid warming at the Greenland Stadial (GS)-GI transition, the trend during the first part of the GI is a Greenland cooling and an Iberian warming. This increase of the North Atlantic climatic gradient led to moisture transportation to Greenland from midlatitudes...

Tipo: Text

Palavras-chave: Greenland interstadial; Iberia; Dansgaard-Oeschger variability; North Atlantic; Precipitation source; Pollen.

Ano: 2009

URL: https://archimer.ifremer.fr/doc/00218/32912/31412.pdf

Modern palynological record in the Bay of Brest (NW France): Signal calibration for palaeo-reconstructions

Lambert, Clement; Vidal, Muriel; Penaud, Aurelie; Combourieu-nebout, Nathalie; Lebreton, Vincent; Ragueneau, Olivier; Gregoire, Gwendoline.

Modern palynological investigations (pollen and non-pollen palynomorphs) have been carried out for the first time in the entire Bay of Brest (BB; NW France), a semi-enclosed oceanic basin flooded during the Holocene that today is exposed to both marine (North Atlantic surface waters) and fluvial (Aulne and Elorn rivers) influences. Palynological analyses were conducted on 41 surface sediments collected in several mudded bays where low-energy conditions prevail, allowing for fine particle decantation, and also on 12 moss samples considered to be pollen rain collectors taken on the periphery of the BB. Furthermore, the BB allows a direct comparison between landscapes and fossilized pollen assemblages in sediments thanks to relatively small watersheds and...

Tipo: Text

Palavras-chave: Pollen; Dinocyst; Surface sediment; Estuarine dynamics; Vegetation cover.

Ano: 2017

URL: https://archimer.ifremer.fr/doc/00382/49371/49784.pdf

Vegetation and environments since the Last Glacial Maximum in the Southern Tablelands, New South Wales

Terrestrial plant microfossils in palaeoenvironmental studies, pollen, microcharcoal and phytolith. Towards a comprehensive understanding of vegetation, fire and climate changes over the past one million years

Kemp, Justine; Hope, Geoff.

Regional changes in vegetation and environment in the last 16 ka have been reconstructed from Micalong Swamp and Willigobung Swamp (35 degrees S) on the western Southern Tablelands of New South Wales (NSW). Micalong Swamp lies at 980m above sea level (a.s.l.), which is close to the subalpine treeline at this latitude. Willigobung Swamp (780m a.s.l.) approaches the modern ecotone between dry and wet montane forest formations. The sites are sensitive to shifts in temperature and precipitation and are the first reported pollen records from the western montane slopes of NSW. A radiocarbon-based chronology indicates that Micalong Swamp was a swampy, gravel floodplain surrounded by alpine grassland before 16.1 ka. Subalpine woodland may have become established...

Tipo: Text

Palavras-chave: Charcoal; Fen peatlands; Late Quaternary; Pollen; South-eastern Australia; Vegetation history.

Ano: 2014

URL: https://archimer.ifremer.fr/doc/00289/40059/39334.pdf

Pollen Evolution in Yams (Dioscorea: Dioscoreaceae)

Daniau, Anne-laure; Desprat, Stéphanie; Aleman, Julie C.; Bremond, Laurent; Davis, Basil; Fletcher, William; Marlon, Jennifer R.; Marquer, Laurent; Montade, Vincent; Morales-molino, César; Naughton, Filipa; Rius, Damien; Urrego, Dunia H..

The Earth has experienced large changes in global and regional climates over the past one million years. Understanding processes and feedbacks that control those past environmental changes is of great interest for better understanding the nature, direction and magnitude of current climate change, its effect on life, and on the physical, biological and chemical processes and ecosystem services important for human well-being. Microfossils from terrestrial plants – pollen, microcharcoal and phytoliths – preserved in terrestrial and marine sedimentary archives are particularly useful tools to document changes in vegetation, fire and land climate. They are well-preserved in a variety of depositional environments and provide quantitative reconstructions of past...

Tipo: Text

Palavras-chave: Pollen; Microcharcoal; Phytolith; Terrestrial and marine sedimentary archives; Vegetation; Fire; Middle Pleistocene; Last glacial period; Holocene.

Ano: 2019

URL: https://archimer.ifremer.fr/doc/00485/59705/83610.pdf

Schols, P.; Wilkin, P.; Furness, C.; Huysmans, S.; Smets, E..

Pollen character evolution in yams (Dioscorea: Dioscoreaceae) was investigated in relation to the phylogeny obtained from a recent combined analysis of rbcL and matK gene sequences. The following characters were evaluated: pollen size, aperture number, sexine ornamentation, perforation density, and orbicule presence or absence. Continuous characters were coded using the gap weighting method. Each character was optimized using MacClade onto a tree selected at random from analyses based on molecular data of Wilkin et al. The results indicate that in Dioscorea pollen size decreases in the more derived clades. The latter observation may be related to the evolution of annually replaced tubers. Aperture number increases from one in the monosulcate Stenophora...

The manifold characters of orbicules: structural diversity, systematic significance, and vectors for allergens

Palavras-chave: Dioscorea; Dioscoreaceae; Pollen; Evolution; Phylogeny.

Ano: 2005

URL: http://www.repository.naturalis.nl/record/407309

Vinckier, S.; Cadot, P.; Smets, E..

In the anthers of flowering plants, gymnosperms, and seed ferns, tiny (¡1 mm) granules might occur on the radial and innermost tangential wall of secretory tapetum cells. These sporopollenin granules develop simultaneously with the pollen exine and are called orbicules or Ubisch bodies. The present paper focuses on two quite different topics associated with orbicules. The morphological and ultrastructural diversity of orbicules in the order Gentianales is summarized, and it is demonstrated that orbicules are a plesiomorphic feature in the order. Furthermore, orbicule characters seemed to be correlated with evolutionary trends in pollen dispersal unit and tapetum type features. In the second part, we report on our investigation of Corylus avellana L....

Type specimens of birds in the National Museum of Natural History, Leiden. Part 2. Passerines: Eurylaimidae – Eopsaltriidae (Peters’s sequence).

Palavras-chave: Orbicules; Morphology; Diversity; Gentianales; Plesiomorphic feature; Pollen; Corylus avellana L..

Ano: 2005

URL: http://www.repository.naturalis.nl/record/407306

Dekker, R.W.R.J..

The type specimens present in the National Museum of Natural History, Leiden, are listed for the Passerine families Eurylaimidae up to and including the Eopsaltriidae (following the sequence in Peters’s Check-list of the Birds of the World).

Palynotaxonomy of the genus Gladiopappus (Dicomeae, Asteraceae) with special emphasis on the exine ultrastructure and mesoapertures

Palavras-chave: Aves; Passerines; Types; Nationaal Natuurhistorisch Museum; Rijksmuseum van Natuurlijke Historie; Bernstein; Bonaparte; Büttikofer; Finsch; Forsten; Hoedt; Junge; Kuhl; Mees; Müller; Pel; Pollen; Schlegel; Schwaner; Temminck; Van Dam; Van Hasselt; Van Oort; Von Rosenberg; Von Siebold; 42.83.

Ano: 2004

URL: http://www.repository.naturalis.nl/record/214679

Pereira Coutinho, A.; Sá da Bandeira, D.; Currais, L.; Soukiazes, E.; Ortiz, S..

The pollen morphology of Gladiopappus vernonioides was studied with transmission (TEM) and scanning (SEM) electron microscopy and with light microscopy (LM). An Anthemoid pattern of exine ultrastructure was found. The pollen morphology of Gladiopappus supports the inclusion of this genus in the tribe Dicomeae and subtribe Dicominae but not in the Mutisieae s.str. The apertural system of G. vernonioides includes a mesoaperture that intersects the foot layer and the upper layer of the endexine, a condition already pointed out for several tribes of Asteroideae (Helenieae, Gnaphaliinae, Heliantheae, Inuleae, Senecioneae) and Carduoideae (Cardueae, Dicomeae). It is suggested that the existence of an intermediate aperture could characterize the apertural system...

Orbicules do not significantly contribute to the allergenic micro-aerosol emitted from birch trees

Palavras-chave: Dicomeae; Exine; LM; Mutisieae; Pollen; SEM; TEM.

Ano: 2018

URL: http://www.repository.naturalis.nl/record/655821

Vinckier, S.; Cadot, P.; Grote, M.; Ceuppens, J.L.; Smets, E..

Pollen morphological variation in Vanguerieae (Ixoroideae - Rubiaceae)

Palavras-chave: Betula verrucosa 1; Betula verrucosa 7; Immunogold electron microscopy; Pollen; Ubisch bodies; 42.40.

Ano: 2006

URL: http://www.repository.naturalis.nl/record/422330

Lens, F.; Jansen, S.; Huysmans, S.; Robbrecht, E.; Smets, E..

The Vanguerieae is a large tribe of the subfamily Ixoroideae (Rubiaceae) and consists of about 500 species in 27 genera. This study gives a detailed pollen morphological description of 30 species from 16 genera, based on light microscopy and scanning electron microscopy. The Vanguerieae are considered to be stenopalynous, although there is some evidence to question this. First, there is a difference in sexine types that clearly de® nes Keetia and Psydrax ( both reticulate) , and Canthium and Vanguerieae (both perforate with very small perforations) from the other Vanguerieae investigated. Second, pollen grains corroborate the subgeneric delimitations of Canthium sensu Bridson. Pollen morphologically the tribe is characterised by ( 1) the shape of the...