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Abstract: This paper investigates changes in the vegetation and hydrology at Ljubljansko barje (Slovenia) using a multi-proxy approach (pollen, diatoms, geochemical and stable isotope analysis). During the Lateglacial Ljubljansko barje was a deep, oligotrophic lake surrounded by open woodland comprised predominantly of Pinus and Betula which in the early Holocene, when the lake became shallower and mesotrophic (Fragilaria pinnata, δ 15N~3.3‰, δ 13C~−33.7‰, C/N~7.9), was replaced by broadleaved tree taxa (Tilia, Ulmus, Quercus, Corylus) and Picea. This was followed by the spread of Fagus and after ~9200 cal yr BP Abies and planktonic and oligotrophic diatom taxa (Aulacoseira italica, Gomphonema angustum) as well as an increased allochthonous influx (silt, SiO2, Al2O3). Between ca. 6750 and 6000 cal yr BP the diatom data suggest shallower and oligotrophic conditions, whereas the stable isotope record (increased δ 13C and decreased δ 15N) indicates terrestrial input. Changes in forest composition (increase of Quercus, Alnus, Corylus) and the spread of herb taxa were probably advanced by human impact on the environment. The beginning of organic sedimentation, dated to 6000 cal yr BP, was followed by an increase of Fagus and Abies and by eutrophication and peat growth at ~5200 cal yr BP. [Copyright &y& Elsevier]

Abstract: This paper describes a multi-core lake sediment study using pollen, diatoms, and chironomids, together with magnetics and sediment biogeochemistry, as biotic and abiotic proxies to infer lake development in response to environmental change during the Holocene at Lochnagar in the eastern Highlands of Scotland. Diatoms are used to infer pH, chironomids to infer temperature, with pollen and plant megafossils acting as an independent proxy to validate these records and to provide insights into changes in catchment vegetation and soils. Lipid biomarkers are explored for their potential to provide additional information on lake productivity. The results indicate highly distinctive fluctuations in the loss-on-ignition (LOI) record, which are in phase with changes in some biotic (chironomid head-capsule concentration) and abiotic (coarse silt particle size fraction, and lipid and chlorine fractions) variables. Catchment-driven changes due to the development and degredation of soils, and the natural succession and human intervention on terrestrial catchment vegetation have the strongest influence on the diatom and chironomid assemblages. These catchment processes resulted in the natural acidification of the lake water. Post-industrial acidification of the lake was also influential on the lake biota. Climate-driven temperature change appears to have had only a weak influence on the biota with declines in cold stenothermic chironomid taxa in response to Early Holocene warming and declines in thermophilic chironomids in response to cooling at about 2600 cal. yr BP. [Copyright &y& Elsevier]