High-resolution pollen records from Lake Baikal revealed considerable regional differences in the vegetation development and pronounced climate variability during the last glacial-interglacial transition and Holocene. Correlation between cores was successfully based on a chronology constructed from AMS 14 C dating of pollen concentrates. Comparison to other radiocarbon-dated pollen sequences from the Baikal region suggests that the chronology presented is very reliable and thus correlation to other dated events can easily be performed. Pollen indices, which reflect relative changes in major vegetation types and limitations of growing conditions by moisture availability and temperature, demonstrate near-synchronous vegetation changes, which suggest synchronous large-scale climate variation across the Baikal region. Due to the low level or even absence of human impact in the Lake Baikal region, the pollen data illustrate that in the continental interior of NE Eurasia Holocene climate variability was very pronounced. After initial warming and a strong increase in relative moisture (ca. 15-14.6 cal ka BP) the Bölling / Alleröd like event was punctuated by three cool and dry events. These events at approx. 14.2 ka BP, 13.8 ka BP and 13.2 cal ka BP can be compared to coolings as recorded in GISP 2 oxygen isotope records from Greenland ice cores. An expansion of Betula sect.Nane/Fruticosae, Artemisia and Chenopodiaceae marks the Younger Dryas-like cooling event (ca. 12.5-12 cal ka BP). High temperatures and favourable moisture conditions during the first part ofHolocene favoured the optimum development of dark-coniferous taiga between 10-8 cal ka BP in the south and 9.0-7.5 cal ka in the northeast. A fir and spruce decline in the southern mountains (ca. 8-7 cal ka BP) can be related to the 8.2 cal ka BP cooling event. The pronounced mid-Holocene cooling event and a transition towards dry conditions (ca. 7.0-5.5 cal ka BP) preceded the nearly synchronous regional expansion of pine taiga.Maximum distribution of Scots pine forests marks the Holocene thermal optimum (ca. 6.5 -5.7 cal ka BP), which was followed by two subsequent cooling events (ca. 5.5-

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Abstract. A new global synthesis and biomization of long (> 40 kyr) pollen-data records is presented and used with simulations from the HadCM3 and FAMOUS climate models and the BIOME4 vegetation model to analyse the dynamics of the global terrestrial biosphere and carbon storage over the last glacial–interglacial cycle. Simulated biome distributions using BIOME4 driven by HadCM3 and FAMOUS at the global scale over time generally agree well with those inferred from pollen data. Global average areas of grassland and dry shrubland, desert, and tundra biomes show large-scale increases during the Last Glacial Maximum, between ca. 64 and 74 ka BP and cool substages of Marine Isotope Stage 5, at the expense of the tropical forest, warm-temperate forest, and temperate forest biomes. These changes are reflected in BIOME4 simulations of global net primary productivity, showing good agreement between the two models. Such changes are likely to affect terrestrial carbon storage, which in turn influences the stable carbon isotopic composition of seawater as terrestrial carbon is depleted in 13C.

ABSTRACT. This work focuses on the preparation and dating of sporomorph (pollen and spores) concentrates of high purity. Three sediment cores recovered from Lake Baikal within the EU-Project CONTINENT were subjected to palynological analyses and accelerator mass spectrometry (AMS) radiocarbon dating. Laboratory processing of concentrates was aimed at the removal of non-sporomorph organic matter by means of chemical treatment, micro-sieving, and heavy liquid separation. The obtained concentrates were checked under the microscope and sample purity was estimated on the basis of particle counts. The results of AMS 14 C dating show differences in the sedimentation rate among 3 sites of Lake Baikal. METHODSLake Baikal is situated in southeast Siberia in the eastern part of the Russian Federation near the Mongolian border. It is the largest (20% of the total volume of surface freshwater), deepest (>1600 m), and probably oldest (about 25 million yr) lake on Earth.Radiocarbon dating of Lake Baikal sediments is a difficult challenge, as previous studies have proved (Coleman 1996). The main problem is the scarcity of material suitable for dating because the sediments are very poor in organic matter and carbonates. Our work focused on the preparation and dating of high-purity sporomorph concentrates.Three sediment cores recovered from Lake Baikal were subjected to palynological analyses and AMS 14 C dating. The cores come from 3 different locations: Posolskoe Bank, Vydrino Shoulder, and Continent Ridge (see Figure 1). The cores subjected to dating were collected with the use of a Kasten corer, which gives the best assurance of complete recovery of the sediment.The preliminary knowledge about sporomorph concentrations and sporomorph assemblages in Holocene and Late Glacial core sections, necessary for selecting appropriate subsampling levels, was gained during palynological analyses of these cores. Sample sizes ranged between 20 and 160 cm 3 (see Table 1), depending on available material, pollen concentrations, and a rough calculation of pollen mass and carbon content using data available from previous studies (Erdtman 1969;Brown et al. 1989). The volume of samples taken for preparation was adjusted to obtain a minimum carbon content of about 2-4 mg per sample. Extraction of SporomorphsLaboratory processing of pollen and spore concentrates was aimed at achieving a high purity of the samples. The removal of inorganic and non-sporomorph organic matter was carried out using chemical treatment, micro-sieving, and heavy liquid separation.

Abstract. Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial), paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059) over the past ∼ 8000 years and evaluate the applicability of inorganic-and organic-based proxies in this particular setting.All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index) show that lacustrine conditions occurred in the Little Belt until ∼ 7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish-marine conditions of the Littorina Sea stage (more saline and warmer) occurred within ∼ 200 years when the connection to the Kattegat became established after ∼ 7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity.Published by Copernicus Publications on behalf of the European Geosciences Union. U. Kotthoff et al.: Little Belt multi-proxy comparisonThe reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 • C for bottom waters and up to 16 • C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg / Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEX L 86 ) can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant changes in depositional settings: in the case of our study, the change from freshwater to marine conditions. Our study shows that particular caution has to be taken when applying and interpreting proxies in coastal environments and marginal seas, where water mass conditions can experience more rapid and larger changes than in open ocean settings. Approaches using a multitude of independent proxies may thus allow a more robust paleoenvironmental assessment.

Integrated Ocean Drilling Program Expedition 347 aimed to retrieve sediments from different settings of the Baltic Sea, encompassing the last interglacial-glacial cycle to address scientific questions along four main research themes: 1. Climate and sea level dynamics of marine isotope Stage (MIS) 5, including onsets and terminations; 2. Complexities of the latest glacial, MIS 4-MIS 2; 3. Glacial and Holocene (MIS 2-MIS 1) climate forcing; and 4. Deep biosphere in Baltic Sea Basin (BSB) sediments. These objectives were accomplished by drilling in six subbasins: (1) the gateway of the BSB (Anholt), where we focused on sediments from MIS 6-5 and MIS 2-1; (2) a subbasin in the southwestern BSB (Little Belt) that possibly holds a unique MIS 5 record; (3, 4) two subbasins in the south (Bornholm Basin and Hanö Bay) that may hold long complete records from MIS 4-2; (5) a 450 m deep subbasin in the central Baltic (Landsort Deep) that promises to contain a thick and continuous record of the last ~14,000 y; and (6) a subbasin in the very north (Ångermanälven River estuary) that contains a uniquely varved (annually deposited) sediment record of the last 10,000 y. These six areas were expected to contain sediment sequences representative of the last ~140,000 y, with paleoenvironmental information relevant on a semicontinental scale because the Baltic Sea drains an area four times as large as the basin itself. The location of the BSB in the heartland of a recurrently waning and waxing ice sheet, the Scandinavian Ice Sheet, has resulted in a complex development: repeated glaciations of different magnitudes, sensitive responses to sea level and gateway threshold changes, large shifts in sedimentation patterns, and high sedimentation rates. Its position also makes it a unique link between Eurasian and northwest European terrestrial records. Therefore, the sediments of this largest European intracontinental basin form a rare archive of climate evolution over the latest glacial cycle. High sedimentation rates provide an excellent opportunity to reconstruct climatic variability of global importance at a unique resolution from a marine-brackish setting. Comparable sequences cannot be retrieved anywhere in the surrounding onshore regions. Furthermore, and crucially, the large variability (salinity, climate, sedimentation, and oxygenation) that the BSB has under