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The Quaternary pteropod records published in the late 1990s from the Indian Ocean provided vital information on past oceanographic and climatic changes in this region. This paper reviews the published work on pteropod preservation and abundance in the Indian Ocean to evaluate the usefulness of this microfossil group in palaeoceanographic reconstructions. Their aragonitic shell chemistry makes them reliable indicators of ocean acidification, paleaoceanography and paleoclimate. An increased interest in studying this faunal group has arisen from recent findings on the vulnerability of aragonite shell preservation to human impacted water column chemistry changes. The compiled pteropod studies show that most of the pteropod databases contain information on abundance and distribution. However, the biogeochemical parameters and processes, such as aragonite production in the water column, their settling fluxes and the shell dissolution patterns are less explored. Despite the wide geographical range of pteropods and their significance in the marine food web, the ecology and taxonomy of the holoplanktonic gastropods in the Indian Ocean are poorly known. Though these pteropods are recovered in plankton tows (standing crop) and sediment traps (settling fluxes), the surface sediments in large parts of the northern Indian Ocean are completely devoid of them. Thus, assessing their fate in the water column and the sediment–water interface and their response to prevailing biogeochemical conditions are worth pursuing. Genomic studies and isotopic and elemental chemistry of living and fossil pteropods could help assess their response to ecological changes. To date, such modern techniques have been little utilized in studying Indian Ocean pteropods. A knowledge of their shell chemistry is crucial in the context of increased input of anthropogenic CO2 and the susceptibility of pteropod preservation to changing climate. [ABSTRACT FROM AUTHOR]

The dynamics of the last Fennoscandian Ice Sheet (FIS) are relatively well constrained in the Nordic countries. Ice‐sheet dynamics in NW Russia, however, are comparatively less well understood owing to the scale and resolution of existing studies. New large‐scale glacial geomorphological datasets from NW Russia based on high‐resolution remotely sensed imagery allow for an independent reassessment of the extent and dynamics of the FIS during the Younger Dryas and Early Holocene (c. 12.9–10 ka) in NW Russia. The reconstruction provides a more detailed link between geomorphological expressions of palaeoglaciation than previous proposals. Rather than a continuous Younger Dryas ice marginal zone (IMZ) stretching from Finland to northern Norway, the geomorphological signature of NW Russia reveals 14 IMZs that document discrete stationary ice‐margin positions (possibly standstill and/or readvance events) during the overall retreat. The relative age sequence of the IMZs, supported by an updated numerical age database, suggests that they formed time‐transgressively during the Younger Dryas and Early Holocene rather than contemporaneously. Moreover, specific landform assemblages reveal contrasting glacial landsystems in NW Russia: (i) a northern subpolar glacial landsystem; and (ii) a southern temperate glacial landsystem. The model presented herein provides robust empirical constraints for testing and validating numerical ice‐sheet models and understanding ice‐sheet responses to rapid climate change. [ABSTRACT FROM AUTHOR]

To better understand the environmental variability during the Holsteinian interglacial, fauna of the palaeolake deposits at Ortel Królewski II, eastern Poland was investigated. The analysis covered the uppermost part of the profile, representing the so‐called pre‐optimal part of the Holsteinian interglacial (MIS 11c), namely the Taxus and Pinus‐Larix pollen zones. Variability within the structure and composition of the faunal assemblage enabled a high‐resolution palaeoecological reconstruction – lake level and temperature fluctuations, its trophy and energy of the environment. During the Taxus pollen zone the lake was relatively deep and characterized by medium trophy conditions, which is indicated by a low abundance of molluscs of temporary water bodies and low numbers of Metacypris cordata and Scottia tumida. The temperature was rather stable with only small fluctuations during the transition between the Taxus and Pinus‐Larix zones. The occurrence of some cold‐loving ostracod species within the beginning of the Pinus‐Larix pollen zone indicates some deterioration of thermal conditions, which was additionally confirmed by using the mutual ostracod temperature range (MOTR) method. Lake level drop and expansion of reed zones within the Pinus‐Larix pollen zone are inferred from the increased abundance of shallow water ostracod and mollusc species as well as from an increased Bithynia‐index (BIN). The short cooling event documented early in the Pinus‐Larix zone in the studied profile might be an equivalent to the mid‐MIS 11c cooling, the so‐called Older Holsteinian Oscillation. Thus, the improved knowledge about the climate dynamics recorded within the sediments from this site contributes to a better understanding of the spatial extent and pattern of the climatic changes within the Holsteinian interglacial across Europe. [ABSTRACT FROM AUTHOR]

Predicting the effects of ongoing climate warming on vegetation requires a long‐term perspective of past ecosystem dynamics. We therefore analysed the sedimentary record from the mire Gola di Lago (985 m a.s.l.) in southern Switzerland, to better understand the vegetation response to past rapid climate change. We present a high‐resolution pollen and plant macrofossil study from the Lateglacial to the Early Holocene (13 400–10 400 cal. a BP), a climatic transition that represents a close analogue to current global warming. The vegetation responses during this time match previously analysed palaeoecological sites south of the Alps. At the end of the Bølling‐Allerød interstadial, the site was surrounded by open larch forest. The beginning of the Younger Dryas was characterized by the local presence and rapid expansion of Pinus cembra, whereas the second part was dominated by Pinus sylvestris, Betula and Larix decidua. These vegetation dynamics agree well with independent climate data indicating a cold and dry start and a subsequent shift to slightly warmer climate. The following rapid temperature increase at the beginning of the Holocene resulted in an increase in forest density and the establishment of novel temperate vegetation assemblages, without major changes in species diversity. Noteworthy, during the Younger Dryas–Early Holocene transition, long‐lived cold‐adapted tree line species such as P. cembra and L. decidua persisted over several centuries, while open boreal forests dominated by P. sylvestris and Betula expanded, indicating high resilience to climatic changes. The results of Gola di Lago suggest that climate warming led to a significant change in vegetation communities through species range shifts. Our study also indicates that some species may potentially be able to locally persist under current global warming, forming novel vegetation assemblages with newly establishing species. [ABSTRACT FROM AUTHOR]

Developing a long‐term understanding of the cryosphere is important in the study of past climatic change. Here we used a nested approach combining diverse instrumental (monthly meteorological data from four weather stations, as well as gridded data) and proxy data (based on blue intensity measurements from local tree ring records) to create a reconstruction of past summer temperature for the central Jotunheimen area in southern Norway. This record was then used to reconstruct annual glacier mass balance from 1962, the start of the yearly measurements, back to 1722, immediately prior to the regional Little Ice Age maximum. Our reconstruction of the 'average' Jotunheimen cumulative glacier mass balance is based on three representative glaciers (Storbreen, Hellstugubreen and Gråsubreen) that were synthesized into one composite record which we term 'Gjennomsnittsbreen' ('mean glacier' in Norwegian) to filter out localized controls on the behaviour of individual glaciers. While not ignoring the role of precipitation on glacier mass balance, our reconstruction demonstrates that glaciers in this region exhibit a strong summer temperature control and appear to have been declining more or less continuously since the mid‐18th century. However, it also shows that this long‐term trend of overall retreat in Jotunheimen is punctuated by relatively short‐lived periods of neutral or occasionally positive glacier mass balance, signifying periods of stillstand or small‐scale glacier advance. These periods or 'events' in our reconstruction were compared with an independent record of 12 moraine‐building events developed using lichenometry. A minimum of 10 of the moraine‐building events identifiable in our reconstruction were also identifiable in the lichenometric data which affords confidence in the performance of our interrogative model. A critical implication of this successful glacier mass balance reconstruction based on just summer temperature is that for Jotunheimen – in contrast to Norwegian maritime glaciers further to the west – there is no need (as was proposed in some previous studies) to invoke large, prolonged increases in winter snowfall to explain glacier advances, not even for events such as the Little Ice Age. [ABSTRACT FROM AUTHOR]

Lake‐level reconstructions are a key tool in hydro‐climate reconstructions, based on the assumption that lake‐level changes primarily reflect climatic changes. Although it is known that land cover changes can affect evapotranspiration and groundwater formation, this factor commonly receives little attention in the interpretation of past lake‐level changes. To address this issue in more detail, we explore the effects of land cover change on Holocene lake‐level fluctuations in Lake Tiefer See in the lowlands of northeastern Germany. We reconstruct lake‐level changes based on the analysis of 28 sediment records from different water depths and from the shore. We compare the results with land cover changes inferred from pollen data. We also apply hydrological modelling to quantify effects of land cover change on evapotranspiration and the lake level. Our reconstruction shows an overall lake‐level amplitude of about 10 m during the Holocene, with the highest fluctuations during the Early and Late Holocene. Only smaller fluctuations during the Middle Holocene can unambiguously be attributed to climatic fluctuations because the land cover was stable during that period. Fluctuations during the Early and Late Holocene are at least partly related to changes in natural and anthropogenic land cover. For several intervals the reconstructed lake‐level changes agree well with variations in modelled groundwater recharge inferred from land cover changes. In general, the observed amplitudes of lake‐level fluctuations are larger than expected from climatic changes alone and thus underline that land cover changes in lake catchments must be considered in climatic interpretations of past lake‐level fluctuations. [ABSTRACT FROM AUTHOR]

The Late Pleistocene and Holocene in western Asia is characterized by frequent, millennial‐scale, high‐amplitude environmental climatic changes. However, little is known about palaeoclimate conditions on the arid Central Iranian Plateau and knowledge of palaeosols and past phases of pedogenesis in relation to climatic events is scarce. Nevertheless, these palaeosols contain important information on the Last Glacial–Interglacial cycle and Holocene climate and environmental changes in the region. Three representative pedons with eight argillic horizons from the interior of the Central Iranian Plateau, namely Isfahan, Jimabad and Bajestan are selected for micromorphological, mineralogical and submicroscopic analyses. The ages of these palaeosols are constrained using the optically stimulated luminescence (OSL) signal from quartz. Micromorphological observations show clay illuviation, carbonate leaching, accumulation of secondary carbonates, calcite depletion, and other characteristic pedogenic features. These characteristics, combined with the luminescence chronology, reveal the presence of well‐developed reddish‐brown palaeoargillic horizons (Btk/Btky) with intensive soil formation processes taking place during the Last Interglacial to Middle Holocene (~107–4.5 ka) in our study area. Pedogenic evidence from the palaeosols suggests steps of polygenetic formation in the argillic horizons in response to alternating wetter and drier phases during this period. Four distinct phases of pedogenesis resulting in Btk/Btky horizons are identified: (i) Marine Isotope Stage (MIS) 5, (ii) MIS 3, (iii) the Last Glacial–Interglacial Transition Holocene, and (iv) the Late Holocene. [ABSTRACT FROM AUTHOR]