Palynology on lake sediments from the Pyrenees

A multi-proxy palaeoecological investigation including pollen, plant macrofossil, radiocarbon and sedimentological analyses, was performed on a small mountain lake in the Eastern Pyrenees. This has allowed the reconstruction of: (1) the vegetation history of the area based on five pollen diagrams and eight AMS14C dates and (2) the past lake-level changes, based on plant macrofossil, lithological and pollen analysis of two stratigraphical transects correlated by pollen analysis. The palaeolake may have appeared before the Younger Dryas; the lake-level was low and the vegetation dominated by cold steppic grasslands. The lake-level rose to its highest level during the Holocene in the Middle Atlantic (at ca. 5060±45 b.p.). Postglacial forests (Quercetum mixtum and Abieto-Fagetum) developed progressively in the lower part of the valley, while dense Pinus uncinata forests rapidly invaded the surroundings of the mire and remained the dominant local vegetation until present. The observed lowering of the lake levels during the Late Atlantic and the Subboreal (from 5060 ± B.P. to 3590±40 b.p.) was related to the overgrowth of the mire. The first obvious indications of anthropogenic disturbances of the vegetation are recorded at the Atlantic/Subboreal boundary as a reduction in the forest component, which has accelerated during the last two millennia.

Icones florae Germanicae et Helveticae simul Pedemontanae, Tirolensis, Istriacae, Dalmaticae, Austriacae, Hungarigae, Transylvanicae, Moravicae, Borussicae, Holsaticae, Belgicae, Hollandicae, ergo Mediae Europae. : Iconographia et supplementum ad opera Willdenowii, Schkuhrii, Persoonii, Decandolli, Gaudini, Kochii aliorumque, exhibens nuperrime detectis novitiis additis, collectionem compendiosam imaginum characteristicarum omnium generum atque specierum quas in sua Flora Germanica excursoria recensuit /

Subtitles vary; v. 1 has special t.p. in Latin and German; v. 25, pt. [2] is without t.-p.

Pollen counts of sediment core MFM6

In recent years enormous success has been achieved in varve counting of the Eifel maar lakes, but a detailed correlation with the biostratigraphy has been missing. In this paper, we present new palynological results of the Lateglacial sequences from Holzmaar Lake and Meerfelder Maar Lake based on annually laminated sediments. In particular, the Meerfelder Maar has great potential, because, in contrast to the Holzmaar, the sequence between the Ulmener Maar Tephra (11 000 varve years BP) and the Laacher See Tephra (12 880 varve years BP) including the Younger Dryas is undisturbed and complete. Therefore, we currently use the Meerfelder Maar chronology (Brauer et al., 1999b) as an independent varve calendar for the biostratigraphy of the Lateglacial. The palynological signals of both maar lakes are in good agreement and can easily be correlated with one another and with type sections/type regions in northwestern Germany and Jutland. The sequences of the Eifel maar lakes have the quality of hypostratotypes with regional biozones based on an absolute time scale.

Age model and pollen analysis from site GIK16867 in the northern Angola Basin

Sporomorphs and dinoflagellate cysts from site GIK16867 in the northern Angola Basin record the vegetation history of the West African forest during the last 700 ka in relation to changes in salinity and productivity of the eastern Gulf of Guinea. During most cool and cold periods, the Afromontane forest, rather than the open grass-rich dry forest, expanded to lower altitudes partly replacing the lowland rain forest of the borderlands east of the Gulf of Guinea. Except in Stage 3, when oceanic productivity was high during a period of decreased atmospheric circulation, high oceanic productivity is correlated to strong winds. The response of marine productivity in the course of a climatic cycle, however, is earlier than that of wind vigour and makes wind-stress-induced oceanic upwelling in the area less likely. Monsoon variation is well illustrated by the pollen record of increased lowland rain forest that is paired to the dinoflagellate cyst record of decreased salinity forced by increased precipitation and run-off.

Pollen and spores of sites GeoB8331 and GeoB8323, Namaqualand Mudbelt, Holocene South Africa

To better understand Holocene vegetation and hydrological changes in South Africa, we analyzed pollen and microcharcoal records of two marine sites GeoB8331 and GeoB8323 from the Namaqualand mudbelt offshore the west coast of South Africa covering the last 9900 and 2200 years, respectively. Our data corroborate findings from literature that climate developments apparently contrast between the summer rainfall zone (SRZ) and winter rainfall zone (WRZ) over the last 9900 years, especially during the early and middle Holocene. During the early Holocene (9900-7800 cal.yr BP), a minimum of grass pollen suggests low summer rainfall in the SRZ, and the initial presence of Renosterveld vegetation indicates relatively wet conditions in the WRZ. Towards the middle Holocene (7800-2400 cal. yr BP), a rather moist savanna/grassland rich in grasses suggests higher summer rainfall in the SRZ resulting from increased austral summer insolation and a decline of fynbos vegetation accompanied by an increasing Succulent Karoo vegetation in the WRZ possibly suggests a southward shift of the Southern Hemisphere westerlies. During the last 2200 years, a trend towards higher aridity was observed for the SRZ, while the climate in the WRZ remained relatively stable. The Little Ice Age (ca. 700-200 cal. yr BP) was rather cool in both rainfall zones and drier in the SRZ while wetter in the WRZ.

Pollen analysis of sediment core GIK16415-2 in the eastern tropical Atlantic

Palynological data of the marine core M 16415-2 show latitudinal shifts of the northern fringe of the tropical rain forest in north-west Africa during the last 700 ka. Savanna and dry open forest expanded southwards and tropical rain forest expanded northwards during dry and humid periods, respectively. Until 220 ka B.P., the tropical rain forest probably kept its zonal character in West Africa during glacials and interglacials. It is only during the last two glacial periods that the rain forest possibly fragmented into refugia. Throughout the Brunhes chron, pollen and spore transport was mainly by trade winds.