Age determination and pollen profile of sediment core Trentelmoor, Peine, northern Germany

The filling up of the lake which existed in the basin of the Trentelmoor (40 km E of Hannover, Germany) - in Preboreal times was finished 2000 years ago. Since then fen vegetation has covered the former lake's surface. The postglacial development of the vegetation follows the pattern which is typical of Central Europe. However, due to the poorness of the soils around the Trentelmoor, the frequencies of some tree species differ. Beech for example never reached - for the benefit of oak - that importance which this tree species usually gains on better soils. Human impact becomes recognisable in the upper Neolithic for the first time. The area has been settled continuously, but with changing intensities, throughout the last 3000 years. When the manuscript of this paper went to press the results of two radiocarbon age determinations only were completed. An additional three determinations were completed somewhat later. See the accompanying table for results.

Dinoflagellates of ODP Leg 104 holes

Dinoflagellate cysts, pollen, and spores were studied from 78 samples of the Eocene to Miocene section of ODP Site 643 at the outer Wring Plateau. Dinoflagellate cysts ranging from less than 1,000 to rarely over 30,000 per gram of sediment in the Paleogene, and generally between 50,000 and 100,000 in the Miocene were present. The shift to conspicuously higher cyst frequencies takes place in the lowermost Miocene section and appears to reflect increased cyst recruitment rather than a change in sedimentation rate. Of the 179 dinoflagellate cyst forms whose ranges were recorded, 129 are known species. Fifteen assemblage zones have been recognized, although the upper Eocene is missing and no substantial lower Eocene was recorded at Site 643. Norwegian Sea and Rockall Plateau zonations were compared with this study. Detailed correlation with existing onshore section zonations was difficult because key zonal species are inadequately represented; however, the middle to upper Miocene zonation established for Denmark is applicable. Pollen and spores occur with relatively low frequencies, and palynodebris is generally absent, in contrast to the observations from DSDP Leg 38. Thirty-nine samples from Eocene to Miocene sediments at Site 642 were studied and correlated with Site 643. A lower Eocene cyst assemblage present in Hole 642D is older than the questionably lower Eocene assemblage from Site 643. Site 642 has a lower Eocene to lower Miocene hiatus.

Quaternary radiolarian counts from Site 181-1123

In the present work Quaternary radiolarian assemblages from the Southwest Pacific were investigated due to their importance for correlation and identification of climatic changes. The studied Ocean Drilling Program (ODP) Site 1123 (Leg 181) is situated on the northern flanks of the Chatham Rise, 1100 kilometres offshore eastern New Zealand and in a water depth o f 3290 metres. It is situated just north of the Subtropical Convergence (STC) in temperate climatic conditions, influenced by the cold deep Deep Western Boundary Current (DWBC) and by the subtropical East Cape Current (ECC) in shallow water depths. A continuous record of 79 sediment samples from this site with a temporal resolution of ~15,000 years provided a medium-resolution record of radiolarian assemblages through the Quaternary. This allowed investigations on how radiolarian assemblages are influenced by climatic variations at obliquity and eccentricity bandwidth, with periodic variations of 40,000, 100,000 and 400,000 years, respectively. Emphasis was given to changes in radiolarian assemblages through the Mid-Pleistocene climate transition (MPT) that marks a fundamental reorganisation in Earth's climate system by change from 40,000 to 100,000 year cycles. Glacial and interglacial variations in oceanography were investigated. Especially the influence of the DWBC was examined due to its input of deep and cold waters to the Pacific Ocean, which plays an important role in Earth's climate system. 167 radiolarian counting groups were examined concerning variations in radiolarian abundance, preservation, diversity, the relative abundance of orders, families, and selected species in order to detect influences of past climatic variations in the Southwest Pacific. No significant changes in radiolarian assemblages were found in coincidence with the onset of the MPT. Investigations led to the recognition of four characteristic phases within the last 1.2 million years. Within one of these phases (Phase Ill), about 160,000 years after the onset of the MPT, fundamental changes in radiolarian assemblages occurred. Investigations yielded highest diversity and highest numbers of nassellarians in abundant samples, whereas sparse samples were mostly poorly preserved and were dominated by spumellarians. Abundance of certain radiolarian families in interglacials or glacials indicated their usefulness as indicators for climatic conditions at Site 1123. Trends o f selected taxa within these families supported the significance of warm- or cool-water preference of these families. Use of 67 radiolarian species as climate indicators showed abundance of warm-water assemblages within interglacials, whereas abundance of cool-water species was increased within glacials. Depth distributional patterns of 52 radiolarian species indicated a strong influence of shallow waters, possibly the EEC, within interglacials and increased influence of deep and intermediate waters, possibly of southern-sourced character and the DWBC in glacial stages.

Benthic foraminiferal assemblages in surface sediments of the Elbe estuary

Two foraminiferal assemblages are observed in surface sediments of the Elbe estuarv. an Elphidium excavatum assemblaae and an Ahmonia/Protelphidium assemblage. They are the result of test-size sorting in accordance to the grain size of the sediments. These assemblages of mainly empty tests differ basically from the living population, which is dominated exclusively by E. excavatum. The average test size is decreasing when advancing from the Open sea into the estuary and the living fauna disappears near the entrance of the Kiel Canal. In the dead assemblage the diversity is distinctively higher and the average test size varies with the grain size of the sediment. The assemblages found in plankton tows are nearly identical with those in corresponding bottom samples. This indicates the distribution pattern to be caused by transport in currents (mainly in suspension). This type of foraminiferal assemblages characterize macro- and mesotidal estuaries and might indicate a high tidal range when observed in sediments of fossil estuaries.

Component composition and benthic foraminifera in sediments of ODP Leg 112

Indicators of surface-water productivity and bottom-water oxygenation have been studied for the age interval from the latest Pleistocene to the Holocene at three holes (679D, 680B, and 68IB) located in the center and at the edges of an upwelling cell at approximately 11°S on the Peruvian continental margin. Upwelling activity was maximal at this latitude during d18O Stages 1 (lower part), 3, the upper part of 5, the lower part of 6, and 7, as documented by high diatom abundance. During these time intervals, the bottom water was poorly oxygenated, as documented by low diversity benthic foraminiferal assemblages that are dominated by B. seminuda s.l. Both surface- and bottom-water-circulation patterns appear to have changed rapidly over short time intervals. Due to changes in surface circulation, the intensity of upwelling decreased, thereby decreasing the concentration of nutrients, and reducing the supply of organic matter to the bottom. Radiolarians became more abundant in the surface waters, and the bottom-water environment was less depleted in oxygen, allowing for the establishment of more diverse benthic foraminiferal assemblages. Surface-water productivity was probably minimal during the early part of d18O Stages 5 and 9, as indicated by the increased abundance of planktonic foraminifers and pteropods and their subsequent preservation.

AMS radiocarbon dates and pollen analysis from Zugspitzplatt

On the strongly karstified and almost unvegetated surface of the Zugspitzplatt, at an altitude of about 2290 m in the Wettersteingebirge, there is a doline within which over a period of several thousand years a bed of fine loess-like sediment, almost 1m thick, has accumulated. Notwithstanding the situation of this locality far above the present tree-line, this infill contains quantities of pollen and spores sufficient for pollen analysis without use of any enrichment techniques. Despite poor pollen preservation, it was possible to date the basal layers of this profile on the basis of their pollen assemblages. AMS dating (7415 ± 30 BP) has confirmed that the oldest sediments were laid down during the early Atlantic period, the time of the thermal optimum of the Holocene. At least since that time this site has never been overridden by a glacier. The moraine associated with the Löbben Oscillation between 3400 and 3100 BP - here represented by the so-called Platt Stillstand (Plattstand) - did not quite reach the doline. A diagram shows known Holocene glacial limits. The composition of the pollen assemblages from the two oldest levels with high pollen concentrations strongly suggests that the distance between the doline and the forest was much less during the Atlantic than at present.

Contribution of woody habitat islands to the conservation of birds and their potential ecosystem services in an extensive Colombian rangeland

The conservation of birds and their habitats is essential to maintain well-functioning ecosystems including human-dominated habitats. In simplified or homogenized landscapes, patches of natural and semi-natural habitat are essential for the survival of plant and animal populations. We compared species composition and diversity of trees and birds between gallery forests, tree islands and hedges in a Colombian savanna landscape to assess how fragmented woody plant communities affect forest bird communities and how differences in habitat characteristics influenced bird species traits and their potential ecosystem function. Bird and tree diversity was higher in forests than in tree islands and hedges. Soil depth influenced woody species distribution, and canopy cover and tree height determined bird species distribution, resulting in plant and bird communities that mainly differed between forest and non-forest habitat. Bird and tree species and traits widely co-varied. Bird species in tree islands and hedges were on average smaller, less specialized to habitat and more tolerant to disturbance than in forest, but dietary differences did not emerge. Despite being less complex and diverse than forests, hedges and tree islands significantly contribute to the conservation of forest biodiversity in the savanna matrix. Forest fragments remain essential for the conservation of forest specialists, but hedges and tree islands facilitate spillover of more tolerant forest birds and their ecological functions such as seed dispersal from forest to the savanna matrix.

Cenozoic terrestrial palynomorphs from the late Oligocene to early Miocene section of sediment core CRP-2/2A (Table 1)

Sparse terrestrial palynomorphs (spores and pollen) were recovered from glacigene Lower Miocene and Oligocene core samples from the Cape Roberts Project (CRP) drillhole CRP-2/2A, Victoria Land Basin, Antarctica. Rarity of palynomorphs probably results from the spares periglacial vegetation in the surrounding landscape at the time of deposition, as well as dilution from rapid sediment accumulation. The Miocene and Late Oligocene vegetation is interpreted as including herb-moss tundra with low-growing woody plants (including Nothofagus and podocarp conifers) in more protected areas, similar to that encountered in the Miocene of CRP-1. Species richness and numbers of specimens increase downhole, a trend that begins very gradually below ~307 mbsf, and increases below ~443 mbsf through the Early Oligocene. These lower assemblages reflect low diversity woody vegetation dominated by several species of Nofhofagus and podocarps, growing in somewhat milder conditions, though still cold temperate to periglacial in the Early Oligocene. The CRP-2/2A core provides new biostratigraphical information, such as the First Appearance Datums (FADS) of Tricolpites sp. a near the Oligocene/Miocene boundary, and Marchantiaceae in the Early/Late Oligocene transition: these are taxa that along with N. lachlaniae, Coptospora spp. and Podocarpidites sp.b characterize assemblages recovered from outcrops of the Pliocene Sirius Group in the Transantarctic Mountains. Some elements of the extremely hardy periglacial tundra vegetation that survived in Antarctica into the Pliocene had their origin in the Oligocene during a time of deteriorating (colder, drier) climatic conditions. The CRP results highlight the long persistence of this tundra vegetation, through approximately 30 million years of dynamically changing climatic conditions. Rare Jurassic and more common Permian-Triassic spores and pollen occur sporadically throughout the core. These are derived from Jurassic Ferrar Group sediments, and from the Permian-Triassic Victoria Group, upper Beacon Supergroup. Higher frequencies of reworked Beacon palynomorphs and coaly organic matter below ~307 mbsf indicate greater erosion of the Beacon Supergroup for this lower part of the core. A color range from black, severely metamorphosed specimens, to light-colored, yellow (indicating low thermal alteration), reworked Permian palynomorphs, indicates local provenance in the dolerite-intruded Beacon strata of the Transantarctic Mountains, as well as areas (now sub-ice) of Beacon strata with little or no associated dolerite well inland (cratonwards) of the present Transantarctic Mountains.