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Over the last few years a number of computational approaches have been developed that enable the optimisation of marine monitoring strategies for CCS. These include methods to: simulate and quantify hypothetical release events, identify highly sensitive criteria by which to distinguish anomalous biogeochemistry which may indicate a seep and define minimum deployments of monitoring platforms which guarantee an acceptable chance of detection. In order for these tools to be operationally useful it is necessary to place them in an accessible and integrated digital format that allows the methodologies to be applied coherently to multiple offshore storage sites and to answer specific stakeholder led questions around required sensitivity, cost and assurance levels. In this work we describe progress towards achieving this integration as well as the site specific data necessary to generate bespoke monitoring guidance.

We will report on preliminary results and present plans for the continuation of an international project, ACTOM. The overall objective of ACTOM is to develop internationally applicable capabilities to design and execute adequate, rigorous and cost-effective monitoring of offshore carbon storage projects, aligning industrial, societal and regulative expectations with technological capabilities and limitations.At the core of the project is a web based pre-operational tool-kit that will deliver new abilities to design a site specific marine monitoring program that will ultimately:enable regulators to quantifiably assess that a proposed monitoring strategy delivers an acceptable standard of assurance, enable operators to properly plan, cost and adapt monitoring strategies to site specific circumstances, enable regulators and operators to communicate to the effectiveness of proposed monitoring strategies to enable informed societal consensus in view of marine spatial planning. Responsible Research and Innovation (RRI) is an approach to anticipate and assess implications and expectations of new technologies on the society, a framework increasingly being used in marine environmental studies and in biotechnology and innovation. We use this framework on Carbon Capture Usage and Storage (CCUS), considering the technology in view of the UN Sustainable Development Goals. In an extension of this, potential legal conflicts between storage projects or other uses of the seas, will be addressed in view of marine spatial planning. By viewing CCUS and offshore storage in view of Sustainable Development Goals (SDG) and in the RRI framework, the aim is to ease communicating the benefits of the technology while addressing the uncertainties and risks in a coherent way.This work is part of the project ACTOM, funded through the ACT programme (Accelerating CCS Technologies, Horizon2020 Project No 294766). Financial contributions made from; The Research Council of Norway, (RCN), Norway, Netherlands Enterprise Agency (RVO), Netherlands, Department for Business, Energy & Industrial Strategy (BEIS) together with extra funding from NERC and EPSRC research councils, United Kingdom, US-Department of Energy (US-DOE), USA. In-kind contributions from the University of Bergen are gratefully acknowledged.

Organic carbon occluded in diatom silica is assumed to be protected from degradation in the sediment. δ13C from diatom carbon (δ13C(diatom)) therefore potentially provides a signal of conditions during diatom growth. However, there have been few studies based on δ13C(diatom). Numerous variables can influence δ13C of organic matter in the marine environment (e. g., salinity, light, nutrient and CO2 availability). Here we compare δ13C(diatom) and δ13C(TOC) from three sediment records from individual marine inlets (Rauer Group, East Antarctica) to (i) investigate deviations between δ13C(diatom) and δ13C(TOC), to (ii) identify biological and environmental controls on δ13C(diatom) and δ13C(TOC), and to (iii) discuss δ13C(diatom) as a proxy for environmental and climate reconstructions. The records show individual δ13C(diatom) and δ13C(TOC) characteristics, which indicates that δ13C is not primarily controlled by regional climate or atmospheric CO2 concentration. Since the inlets vary in water depths offsets in δ13C are probably related to differences in water column stratification and mixing, which influences redistribution of nutrients and carbon within each inlet. In our dataset changes in δ13C(diatom) and δ13C(TOC) could not unequivocally be ascribed to changes in diatom species composition, either because the variation in δ13C(diatom) between the observed species is too small or because other environmental controls are more dominant. Records from the Southern Ocean show depleted δ13C(diatom) values (1-4 ‰) during glacial times compared to the Holocene. Although climate variability throughout the Holocene is low compared to glacial/interglacial variability, we find variability in δ13C(diatom), which is in the same order of magnitude. δ13C of organic matter produced in the costal marine environment seems to be much more sensitive to environmental changes than open ocean sites and δ13C is of strongly local nature. © 2012 Springer Science+Business Media B.V.

The monospecific diatom genus Cavernosa is known from only two locations: Kapiti Island off the west coast of New Zealand and Ile de la Possession, Crozet Archipelago, in the southern Indian Ocean. Cavernosa kapitiana Stidolph is a chain-forming diatom with cylindrical frustules having an elongated valve mantle. We provide a description of the different life-cycle stages (normal frustules, globular initial cells, bell-shaped initial cells, first daughter cells of initial cells) of C. kapitiana based on examination of new material from Ile de la Possession and material from the type locality on Kapiti Island. The most remarkable morphological features include the complex valve face structure composed of pores, granules and ridges, the subdivision of the valve interior into marginal caverns, the complex structure of the mantle and girdle, and the presence and morphology of rimoportulae. The study concludes with an emended species description of C. kapitiana

A 400-year sediment record from an 18 m deep scour hole lake (Haarsteegse Wiel) near the Meuse River in the Netherlands was investigated for past changes in water quality, flooding frequency and landscape change using geophysical, geochemical and micropaleontological information. The results are highly significant for determining long-term trends of water quality, the impact of atmospheric (as SCP, spheroidal carbonaceous particles) and industrial (chromium) pollution on the terrestrial and aquatic flora, and the impact of river floods. The studied sediment record was dated by combining 137Cs activities, biostratigraphical ages, micro-tephra layers, and historically documented floods indicated by the magnetic susceptibility. The oldest flooding event is indicated at AD 1610 when the lake was created by water masses bursting through a dike. Large historical river floods are well documented in regional chronicles and thus may provide reliable age calibration points. Based on assumptions about the timing of flood events and constant rate of sedimentation, it appears that sedimentation rates in Haarsteegse Wiel declined after ca. AD 1880. This decline might be a result of a widespread change from wheat cultivation to pasture land from around AD 1875 as a direct result of falling wheat prices and intensified cattle farming linked to the agricultural crisis in the last quarter of the nineteenth century. Water quality changes and absolute phosphorus concentrations were reconstructed using a diatom-based transfer function. Results show that the currently nutrient-rich lake has mostly been in a mesotrophic state prior to ca. AD 1920, with the exception of several apparently sharp eutrophication events that were coeval with river floods. River flooding also impacted the vegetation composition by importing allochthonous components, and indirectly by the influx of nutrients which had a clear influence on the composition of the water plant communities and aquatic species diversity. Magnetic susceptibility changes and pollen data show that within the period AD 1610-1740, within the Little Ice Age period, several undocumented floods may have occurred. Thus, documentation of geophysical, geochemical, and biological flooding signals in a high-resolution archive present the possibility to detect flooding regimes further back in time. © 2010 Springer Science+Business Media B.V.

We present a palaeolimnological study encompassing five centuries of trophic-state change of the dike-breach lake De Waay located on the Rhine- Meuse delta (the Netherlands). Diatom-inferred total phosphorus (TP) concentrations indicate hypertrophic epilimnetic conditions ((300 l gl -1 TP) since the formation of the lake in the fifteenth century until the end of the eighteenth century. Cladocera data support the reconstructed trophic state and indicate turbid conditions in lake De Waay during this period. High inferred TP concentrations as well as the amount of Ti in the sediment reflect numerous flooding events. From the nineteenth century onwards reconstructed TP concentrations decreased to 40-150 l gl -1 due to improvements in sewage and dike systems that considerably diminished direct river flooding and seepage-derived nutrients. As a consequence, the increased stability of littoral habitats led to an increased diversity of the Cladocera assemblages. The most significant decrease in TP concentrations to *40 l gl -1 occurred between about 1900 and 1930. This mesotrophic phase was a consequence of the isolation of the lake from catchment drainage and the introduction of a highly elaborate flood control during this period. However, since the mid twentieth century a eutrophication trend is preserved in the record, likely related to increased agricultural activity in the vicinity of the lake. Our results emphasize that land- use and trophic-state history must be taken into account when evaluating the ecological status of lakes for water management and protection actions, espe- cially for lakes in landscapes that are strongly modified by human action.

IJsselmeer was formed in 1932 through the closure of the Afsluitdijk that separated the artificial lake from the former Zuiderzee estuary. The palaeoecology of IJsselmeer was studied on a 63-cm-long sediment core. Lithology and microfossil data, particularly the diatom flora, clearly show the transition from the marine Zuiderzee into the freshwater IJsselmeer. Trophic conditions in IJsselmeer since 1932 have been inferred by qualitative and quantitative diatom-based approaches: by plotting the distribution of trophic categories based on published trophic indicator values, by a canonical correspondence analysis (CCA) yielding relative total phosphorus (TP) changes and by applying a transfer function in order to calculate TP concentrations. All three approaches indicate that IJsselmeer initially was meso- to eutrophic. A first hypertrophic period is indicated for the mid-1940s, likely due to internal loading. After 1960, the phosphorus load steadily increased and TP in IJsselmeer reached highest concentrations (ca. 150 µg l−1) in the 1980s as confirmed by monitoring data since 1975. The monitored data show that the TP concentration continuously decreased after 1985 due to successful environmental protection measures. This trend is not (or not yet) evidenced by the diatom data and thus, the diatom-inferred TP concentration.

Although the recent history of human colonisation and impact on Mauritius is well documented, virtually no records of the pre-human native ecosystem exist, making it difficult to assess the magnitude of the changes brought about by human settlement. Here, we describe a 4000-year-old fossil bed at Mare aux Songes (MAS) in south-eastern Mauritius that contains both macrofossils (vertebrate fauna, gastropods, insects and flora) and microfossils (diatoms, pollen, spores and phytoliths). With >250 bone fragments/m(2) and comprising 50% of all known extinct and extant vertebrate species (n(s)=44) of Mauritius, MAS may constitute the first Holocene vertebrate bone Concentration-Lagerstatte identified on an oceanic volcanic island. Fossil remains are dominated by extinct giant tortoises Cylindraspis spp. (63%), passerines (similar to 10%), small bats (7.8%) and dodo Raphus cucullatus (7.1%). Twelve radiocarbon ages [four of them duplicates] from bones and other material suggest that accumulation of fossils took place within several centuries. An exceptional combination of abiotic conditions led to preservation of bones, bone collagen, plant tissue and microfossils. Although bone collagen is well preserved, DNA from dodo and other Mauritian vertebrates has proved difficult. Our analysis suggests that from ca 4000 years ago (4 ka), rising sea levels created a freshwater lake at MAS, generating an oasis in an otherwise dry environment which attracted a diverse vertebrate fauna. Subsequent aridification in the south-west Indian Ocean region may have increased carcass accumulation during droughts, contributing to the exceptionally high fossil concentration. The abundance of floral and faunal remains in this Lagerstatte offers a unique opportunity to reconstruct a pre-human ecosystem on an oceanic island, providing a key foundation for assessing the vulnerability of island ecosystems to human impact. (C) 2008 Elsevier Ltd. All rights reserved.

Diatom assemblages from sediment trap samples collected during ten intervals between October 2003 and October 2005 in Sacrower See (NE Germany) were related to limnological and meteorological data. Sacrower See is a dimictic, 38 m deep, hypertrophic lowland lake (29.5 m a.s.l.). We identified distinct seasonal and interannual changes of diatom assemblages for the studied period. Diatoms showed a typical seasonal succession for temperate, dimictic, and eutrophic lakes. Stephanodiscus parvus, S. hantzschii, S. neoastraea, and S. alpinus had high accumulation rates during winter and spring, whereas species of the genera Stephanodiscus, Fragilaria, and Nitzschia were the predominant diatoms during summer and autumn. In a Canonical Correspondence Analysis, precipitation, air and water temperatures, epilimnetic calcium, pH, and total phosphorus concentrations together explained 70% of the variance of the diatom data. Interannual variability in the diatom assemblages during the two sampled years mainly seems to reflect changes in the total phosphorus concentration and temperature and secondarily the onset of the growing season and of stratification. © 2008 The Author(s).

In this review, we compile the evidence of lake and isolation basin sediments for the chronology of the last deglaciation along the coastal parts of eastern Greenland between 70°N and 83°N. Radiocarbon dates of remains of freshwater plants and bulk organic carbon extracted from lacustrine sediments suggest that the present day ice-free parts of eastern Greenland were not deglaciated prior to the early Holocene. Older dates do exist but must be used with caution due to possible contamination with old carbon. However, many inland locations in eastern North and central East Greenland became ice-free distinctly later between 10,000 and 7500 cal yr BP, depending on their relative position to the ice margin. This compilation confirms former suggestions that hitherto no secure Late glacial lacustrine sediments have been found in the ice-free parts of eastern Greenland. Late glacial sediments are only known from lakes in southern Greenland and from few marine locations off eastern Greenland. The here summarized lake sediment evidence for the last deglaciation supports the results of an earlier compilation of dates from marine shells. © 2007 Elsevier Ltd. All rights reserved.

This paper is a report, on the diatoms and dinoflagellate cysts identified in a sediment core and a water sample recovered from Rookery Bay, a subtropical estuarine system located on the west coast of Florida. Eighty-eight diatom taxa representing 48 genera, many of which have been rarely observed, and 14 dinoflagellate cyst genera with 20 taxa were identified in Rookery Bay. All taxa are briefly annotated and documented by light micrographs. The most common diatom taxa in the surface sediment sample are Amphicocconeis disculoides, Chaetoceros resting spores, Cyclotella litoralis, Cymatosira belgica, Neodelphineis pelagica, Paralia sulcata, and Pleurosigma rhombeum. The most abundant dinoflagellate cyst taxa in the surface sample include Brigantedinium spp., Lingulodinium machaerophomm, Polyspheridium zoharyi, Spiniferites bentorii, and Spinifrites ramosus. Copyright 2007 College of Arts and Sciences.

A 2.73 m long sediment sequence from Loon Lake, located at 18m a.s.l. on outer Geographical Society Ø, East Greenland, was investigated for its chronology and changes in physical and biogeochemical properties, macrofossils, and grain-size distribution. The predominance of marine fossils throughout the sequence, dated by 14C AMS to between 8630 and 7535 cal. yr BP, shows that the Loon Lake at that time was a marine basin, which according to existing sea-level curves was about 15-35 m deep. The sequence mainly consists of fine grained homogeneous sediments, which are interrupted by a 0.72 m thick sandy horizon with erosive basis and distinct fluctuations in the grain-size distribution and in the physical and biogeochemical properties. According to the radiocarbon dates, this sandy horizon was deposited after 8500-8300 cal. yr BP and is interpreted as originating from the Storegga tsunami. The record from Loon Lake provides the first indication of Storegga tsunami deposits from East Greenland. Copyright © 2006 John Wiley & Sons, Ltd.

A survey of the planktonic diatom community was carried out during summer2003 in Lake El’gygytgyn, a deep, cold, low conductive and oligotrophic crater lake inthe Northeast Siberian Arctic. Five planktonic diatom species were identified: Cy-clostephanos dubius , Cyclotella ocellata , Cyclotella tripartita , Pliocaenicus costatus ,and Stephanocostis chantaicus . The morphological details of the five taxa are docu-mented by light and partly also scanning electron micrographs. Additionally, ecologicaland biogeographic data are provided. This is the first evidence of S. chantaicus in a north-east Siberian lake and one of the first findings of P. costatus outside the Baikal Lake re-gion. The diatom community in summer 2003 was almost monospecificly dominated by Cyclotella ocellata (>96%), a species that displays a tremendous morphological variabil-ity. High concentrations and accumulation rates of diatom frustules during the ice-cov-ered period (May–June 2003) indicated considerable under-ice phytoplankton growth.

We document hydrological and phytoplankton characteristics of nine lakes and two ponds on Store Koldewey, a culturally undisturbed island off Northeast Greenland. The limnological survey included the recording of temperature, conductivity, oxygen concentration and saturation, pH, ionic composition, transparency, and the diatom phytoplankton community. In summer 2003, the lakes were cold, monomictic, thermally unstratified, alkaline and likely oligotrophic water bodies. Diatom phytoplankton was present in six lakes and consisted of four dominant species (Aulacoseira tethera, Cyclotella pseudostelligera, C rossii, and Fragilaria tenera). The concentration of planktonic diatoms varied distinctly between the lakes.

This contribution documents with light micrographs the planktonic diatom flora in seven high arctic lakes on Store Koldewey, an island off Northeast Greenland. The lakes have maximum water depths between 6.1 and 72.0 m. Basic limnological analyses indicate that all lakes are cold, monomictic, clear, oligotrophic, and alkaline. Planktonic diatoms and chrysophyte statospores were present in all but one lake. Eight planktonic diatom taxa were identified in the phytoplankton samples: Aulacoseira islandica (O. Müller) Simonsen, Aulacoseira tethera Haworth, Aulacoseira sp. 1, Cyclotella antiqua W. Smith, Cyclotella pseudostelligera Hustedt, Cyclotella rossii Håkansson, Fragilaria tenera (W. Smith) Lange-Bertalot, and Stephanodiscus minutulus (Kützing) Cleve et Möller. Fragilaria tenera was present in two morphotypes; the "normally shaped" type and a type with abnormally shaped valves, which has mostly been recorded in metal-polluted lakes. The diatom communities were generally dominated by only one or two species. The water columns of the lakes with a water depth greater than 10 m accomodate a moderate to high proportion of primarily benthic diatoms.Key words: Greenland, High Arctic, limnology, diatoms, valve morphology.

A 5.52 m long sediment sequence was recovered from Lake Terrasovoje, Amery Oasis, East Antarctica, in order to reconstruct the regional environmental history. The basal sediments, which are dominated by glacial and glaciofluvial clastic sediments, attest to a Late Pleistocene deglaciation of the lake basin. These sediments are overlain by 2.70 m of laminated algal and microbial mats and a few interspersed moss layers. Radiocarbon dating, conducted on bulk organic carbon of 12 samples throughout the organic sequence, provides a reliable chronology since the onset of biogenic accumulation at c. 12,400 cal. year BP. Successful diatom colonization, however, was probably hampered by extensive ice and snow cover on the lake and restricted input of nutrients until 10,200 cal. year BP. A subsequent increase of nutrient supply culminated between 8600 and 8200 cal. year BP and is related to warm summer temperatures and reduced albedo in the catchment. Warm conditions lasted until 6700 cal. year BP, supporting the establishment of a diatom community. Colder temperatures from 6700 cal. year BP culminated in several periods between 6200 and 3700 cal. year BP, when high amounts of sulphur and low abundances of diatoms were deposited due to a perennial ice and snow cover on the lake. During the late Holocene, relatively warm conditions between 3200 and 2300 cal. year BP and between 1500 to 1000 cal. year BP, respectively, indicated by high accumulation of organic matter and reducing bottom water conditions, were interrupted and followed by colder periods.

A mid-Holocene climate optimum is inferred from a palaeosalinity reconstruction of a closed saline lake (Beall Lake) from the Windmill Islands, East Antarctica using an expanded diatom salinity weighted averaging (WA) regression and calibration model. The addition of 14 lakes and ponds from the Windmill Islands, East Antarctica, to an existing weighted averaging regression and calibration palaeosalinity model of 33 lakes from the Vestfold Hills, East Antarctica expands the number of taxa and lakes and the range of salinity in the existing model and improves the model's predictive ability. This improved model was used to infer Holocene changes in lake water salinity in Beall Lake, Windmill Islands. Six changes in diatom-inferred salinity in Beall Lake are put into broad chronological context based on three radiocarbon dates: as the East Antarctic Ice Sheet (EAIS) retreated from the Windmill Islands during the early Holocene (∼9000–8130 corr. yr BP), Beall Lake formed as a melt water-fed freshwater lake, which gradually became more saline as marine influence increased from ∼8000 corr. yr BP. Between ∼8000 and 4800 corr. yr BP, the diatom assemblage included planktonic marine taxa such as Chaetoceros spp. and cryophilic taxa such as Fragilariopsis cylindrus, which indicate favourable summer growth conditions. A mid-Holocene warm period produced a climate that was warmer and more humid with increased precipitation and snow accumulation. This is reflected in the Beall Lake core as a reduction in the salinity of the lake diatom assemblage from ∼4800–4600 corr. yr BP. Holocene isostatic uplift rates in the Windmill Islands vary from 5–6 m/1000 yr. By applying this uplift rate, it is calculated that the bedrock would have risen above sea level by ∼4000 yr BP. The Beall Lake core diatom assemblage from ∼4600–2900 corr. yr BP includes both marine cryophilic and planktonic taxa together with freshwater benthic and planktonic lacustrine taxa. This mix of species indicates the emergence of the lake from the sea around ∼4600 corr. yr BP. From ∼2800 corr. yr BP, retreat of the ice margin led to increasing melt water inputs and associated freshening of the lake basin until ∼1900 corr. yr BP. The lake basin had no oceanic influence by this time, allowing a terrestrial freshwater flora to establish and thrive for the next ∼1000 yr. At ∼1850 corr. yr BP, a sudden and rapid salinity change is evident in Beall Lake. A late Holocene warm period between 2000 and 1000 yr BP has been observed in ice core records from Law Dome (an ice cap abutting the Windmill Islands to the east and north). It is therefore inferred that, at ∼1850 corr. yr BP, summer temperatures within the Beall Lake catchment area were much higher than present summer temperatures. The climate optimum identified in the Beall Lake core ∼4800 yr BP confirms mid-Holocene warming of the Windmill Islands and suggests a synchronous mid-Holocene climate optimum occurred across coastal East Antarctica. In addition, the abrupt climate change inferred at ∼1850 yr BP suggests that higher resolution sampling of sediment cores from coastal East Antarctic limnological oases will provide more evidence of rapid climate change events over coastal East Antarctica in future.

A sediment core recovered in Lake Lyadhej-To at the northwestern edge of the Ural Mountains reflects the complete Holocene environmental history from ∼11,000 cal. yr B.P. Five limnological episodes are identified in the diatom and geochemical records. The initial lake stage, Episode I (∼11,000–10,850 cal. yr B.P.) is characterized by the absence of biogenic production and a high influx of clastic sediments. Episode II (∼10,850–8650 cal. yr B.P.) is characterized by ice-free conditions during summer, highest bioproductivity, strong growth of planktic diatoms and anoxic bottom waters. This period represents the Holocene climatic optimum. Deterioration of climatic conditions commenced in Episode III (∼8650–7000 cal. yr B.P.) as indicated by distinctly lower bioproductivity and longer persistence of winter ice on the lake. During Episode IV (∼7000–2500 cal. yr B.P.), the diatom and pollen records indicate that temperatures were cool and the growing season was short. Finally, in Episode V (∼2500 cal. yr B.P. to present), limnological conditions, indicated by increased organic carbon and diatom deposition, initially suggest improved conditions followed by a return to modern conditions beginning ∼500 cal. yr B.P. The pollen stratigraphy from Lake Lyadhej-To is consistent with other paleoclimatic records from northern Eurasia, confirming rapid postglacial warming, the presence of dense tree forests during the climatic optimum, and finally a gradual southward retreat of the treeline towards its modern location.

Within the framework of a palaeolimnological pilot study, the potential of sedimentary diatom assemblages for the reconstruction of the eutrophication history was studied in short sediment cores from five shallow lakes located in the Romanian Danube Delta. A total of 234 diatom taxa representing 57 genera could be identified but diatom assemblages are generally predominated by a few species only. Loss on ignition percentages, total diatom abundances and diatom downcore successions largely vary within the single sediment cores and between all five lakes. This suggests the presence of various lake environments within the Danube Delta, each characterized by lake-specific geomorphological, sedimentological, hydrological, and biological conditions. Highly variable depositional conditions are also confirmed by radiocesium measurements in two of the five cores suggesting distinct inter-lake differences in the sedimentation rate. Causes for the great intra-lake and inter-lake variability in diatom downcore successions are difficult to specify and may include changes in the physico-chemical conditions, aquatic vegetation cover, water depth, river influence, turbidity and inter-biotic interactions. However, based on this pilot study, it is likely that the spatial and temporal distribution of sedimentary diatom assemblages in Danube Delta lakes were not triggered by the trophic state. The delta lakes likely became meso- to eutrophic long before 1950, possibly during late-Holocene times.

The late Quaternary palaeoenvironmental history of the southern Windmill Islands, East Antarctica, has been reconstructed using diatom assemblages from two long, well-dated sediment cores taken in two marine bays. The diatom assemblage of the lowest sediment layers suggests a warm climate with mostly open water conditions during the late Pleistocene. During the following glacial, the Windmill Islands were covered by grounded ice preventing any in situ bioproductivity. Following deglaciation, a sapropel with a well-preserved diatom assemblage was deposited from ∼10 500 cal yr BP. Between ∼10 500 and ∼4000 cal yr BP, total organic carbon (Corg) and total diatom valve concentrations as well as the diatom species composition suggest relatively cool summer temperatures. Hydrological conditions in coastal bays were characterised by combined winter sea-ice and open water conditions. This extensive period of glacial retreat was followed by the Holocene optimum (∼4000 to ∼1000 cal yr BP), which occurred later in the southern Windmill Islands than in most other Antarctic coastal regions. Diatom assemblages in this period suggest ice-free conditions and meltwater-stratified waters in the marine bays during summer, which is also reflected in high proportions of freshwater diatoms in the sediments. The diatom assemblage in the upper sediments of both cores indicates Neoglacial cooling from ∼1000 cal yr BP, which again led to seasonally persistent sea-ice on the bays. The Holocene optimum and cooling trends in the Windmill Islands did not occur contemporaneously with other Antarctic coastal regions, showing that the here presented record reflects partly local environmental conditions rather than global climatic trends.

Lake El'gygytgyn, an impact crater lake in northeastern Siberia, was analysed based on water-column characteristics and the modern and sub-recent diatom flora. Vertical temperature, conductivity and oxygen profiles, as well as ionic concentrations in the lake water, reveal that Lake El'gygytgyn is a clear, cold-monomictic, ultra-oligotrophic high-Arctic lake with high light-penetration depth. We identified 113 diatom taxa, of which only 2 species are planktic diatoms. Cyclotella ocellata is the only quantitatively significant diatom present in the modern phytoplankton community, and is also predominant in a short sediment core, which probably reflects the mid- and late-Holocene environmental history of Lake El'gygytgyn. Pliocaenicus costatus var. sibiricus is also common but of minor importance. This is the first evidence of P. costatus var. sibiricus outside the Lake Baikal region.

The limnology and sedimentary diatom flora of fourteen lakes and ponds from the Windmill Islands, East Antarctica, is presented. Saline lakes, saline ponds and freshwater ponds are represented in this dataset. The Windmill Island lake diatom flora represents an intermediate floral assemblage between that of the freshwater lakes of the Larsemann Hills and the saline lakes of Vestfold Hills, East Antarctica. Variations within this assemblage are related to water chemistry variables in the Windmill Island lakes. In particular, a lakewater salinity/phosphate gradient can explain the variation observed in the sedimentary diatom flora of the lakes and ponds included in this study.

Information on Holocene lacustrine diatom records from Greenland is rare. Here, a complete Holocene diatom succession is described from a sediment core recovered from Basaltsø, an arctic lake on Geographical Society Ø, eastern Greenland. Based on radiocarbon measurements on plant material, the upper 2.42 m of the 9.85 m long sediment sequence represent the Holocene sedimentological record in this area from about 10 000 calibrated (cal.) years BP. The diatom assemblages in Basaltsø are dominated by only a few species. Four stratigraphic diatom zones could be distinguished. During the early Holocene, mainly Staurosira construens (Ehr.) Williams et Round, Nitzschia amphibia Grunow, and Pinnularia mesolepta (Ehr.) W. Smith were the dominant taxa. After this initial stage, between 9600 and 5000 cal. years BP, Staurosirella pinnata (Ehr.) Williams et Round was the most abundant diatom species. From 4500 to 500 cal. years BP, the diatom assemblage was characterized by the co-occurrence of several taxa, including S. construens. S. pinnata, Kolbesia suchlandtii (Hust.) Kingston, and Cyclotella sp. A (rossii–tripartita–comensis complex) as the main contributors. Finally, from 500 cal. years BP, the diatom assemblage was clearly dominated by Cyclotella sp. A, Cyclotella pseudostelligera Hustedt, and Sellaphora spp. The Holocene relative frequencies of S. pinnata and S. construens clearly correlate with the total diatom valve concentration, the Betula and Salix pollen percentage in Basaltsø, and the oxygen isotope record from the Renland ice core. This suggests that S. pinnata and S. construens are temperature-sensitive species that responded on the general climatic development in eastern Greenland during the Holocene. The diatom record together with the pollen and geochemical data of Basaltsø indicate to the Holocene climatic optimum on Geographical Society Ø from ca. 9000 to 6500 cal. years BP.Key words: Arctic, Greenland, Holocene, diatoms, paleolimnology, environmental change.

A 341 cm long sediment sequence was recovered from the unofficially named Raffles So on Raffles O, outer Scoresby Sund region, East Greenland. The sediment sequence consists in the upper part (0–230 cm) of a stratified gyttja enriched in organic carbon and biogenic silica whereas the lower core part (235–341 cm) is composed of terrigenous, consolidated glacio-limnic sediments. 14C-AMS measurements indicate that the sediment sequence represents the entire Holocene lake history from 10,030 calibrated radiocarbon years. The geochemical parameters (opal, total organic carbon (TOC), total nitrogen (TN)) and the total diatom concentration show similar developments during the Holocene, and reflect changes in biological production and nutrient input into the lake. These records clearly reveal a broad Holocene TOC-opal-maximum interval between 5200 and 1800 cal. yrs BP. The diatom flora consisted of 66 taxa representing 20 genera but only seven taxa were abundant and, sometimes, these were monospecifically dominant during the Holocene. In the sediment core from Raffles So four successive stratigraphical zones can be distinguished. Accumulation of diatom valves began at 9900 cal. yrs BP with a Stephanodiscus minutulus (Kutz.) Cleve and Moller dominated assemblage (stratigraphic zone 1) followed by a diatom flora dominated by Cyclotella pseudostelligera Hustedt and, less frequently, by Diatoma tenuis Agardh (9400 until 5900 cal. yrs BP, zone 2). Cyclotella sp. A, a taxon which belongs to the Cyclotella rossii-comensis-tripartita-complex, was the dominant floral element between 5200 and 1800 cal. yrs BP (zone 3). From 1800 cal. yrs BP, the periphytic taxa Fragilaria capucina var. gracilis (Ostr.) Hustedt and F. capucina var. rumpens (Kutz.) Lange-Bertalot attained highest relative abundances, also almost monospecifically (zone 4). The distribution and composition of the diatom assemblages in the sediment record from Raffles So probably reflect past variations in the extent of the lake-ice cover during the growing season. More or less ice-free conditions during summer may have prevailed during the early Holocene until ca. 1800 cal. yrs BP, which allowed growth of planktonic diatoms (Cyclotella taxa) in the pelagic lake region. From 1800 cal. yrs BP, colder conditions lead to a perennial lake-ice cover with a small ice-free moat in summer which favored the growth of periphytic, littoral species (Fragilaria capucina varieties).

ULTimateCO2 will assess the long-term CO2 storage behaviour in terms of efficiency and security. The project is dedicated to studying the main physical processes needed to develop a better, quantitative understanding of the long- term geological storage of CO2, namely: (i) reservoir trapping, (ii) sealing integrity of caprock, and (iii) well leakage. Close collaboration with the NER300 candidates and EEPR demonstration sites will underpin all investigation with relevant supply of data industrial context. ULTimateCO2 will define a set of recommendations that will enable both regulators and operators to demonstrate that site specific long-term site performance will lead to permanent and safe CO2 containment.

Four spicule-bearing chaetetid sponges are described from Upper Triassic (Norian) reef carbonates of the WesternTaurids (Antalya-Region, SW Turkey): Atrochaetetes alakirensisCuif & Fischer, Blastochaetetes dolomiticusBizzarini & Braga, Ptychochaetetes sp. and ?Bauneia sp.. Spicules are preserved as calcitic pseudomorphs. They are either short and thick or long and slender, corresponding to typical styles; oxes are rarely present in Atrochaetetes alakirensis. The styles are mainly embedded in the secondary rigid skeleton, but their rounded ends appear to be attached to the primary wall. In Blastochaetetes dolomiticus and ?Bauneia sp. styles are also embedded in the primary wall. A comparison of these spicule-skeletons with those of other chaetetids, especially Paleozoic species, confirms the polyphyletic origin of the Taxon Chaetetida.

We review the post-glacial climate variability along the East Antarctic coastline using terrestrial and shallow marine geological records and compare these reconstructions with data from elsewhere. Nearly all East Antarctic records show a near-synchronous Early Holocene climate optimum (11.5-9 ka BP), coinciding with the deglaciation of currently ice-free regions and the optimum recorded in Antarctic ice and marine sediment cores. Shallow marine and coastal terrestrial climate anomalies appear to be out of phase after the Early Holocene warm period, and show complex regional patterns, but an overall trend of cooling in the terrestrial records. A Mid to Late Holocene warm period is present in many East Antarctic lake and shallow coastal marine records. Although there are some differences in the regional timing of this warm period, it typically occurs somewhere between 4.7 and 1 ka BP, which overlaps with a similar optimum found in Antarctic Peninsula terrestrial records. The differences in the timing of these sometimes abrupt warm events in different records and regions points to a number of mechanisms that we have yet to identify. Nearly all records show a neoglacial cooling from 2 ka BP onwards. There is no evidence along the East Antarctic coastline for an equivalent to the Northern Hemisphere Medieval Warm Period and there is only weak circumstantial evidence in a few places for a cool event crudely equivalent in time to the Northern Hemisphere's Little Ice Age. There is a need for well-dated, high resolution climate records in coastal East Antarctica and particularly in Terre Adelie, Dronning Maud Land and Enderby Land to fully understand the regional climate anomalies, the disparity between marine and terrestrial records, and to determine the significance of the heterogeneous temperature trends being measured in the Antarctic today. © 2010 Elsevier B.V.

Significant oil and gas reserves occur in so-called “barren red-beds” in several regions around the world. Although red-beds occur throughout the geological timescale, examples with an economic interest are the Late Carboniferous, Permian and Early Triassic of Europe (Barren Measures, Rotliegendes, Bunter; Doornenbal and Stevenson, 2010), the Triassic of the United States, and the Permian–Carboniferous of the Middle East. These sediments are generally deposited in nonmarine environments under arid climate conditions. In terrestrial basins, biostratigraphic analysis of plant microfossils (pollen and spores) is often effective in constraining static geological models. Unfortunately, such organic-walled microfossils are not preserved in red-bed deposits due to oxidation, hampering stratigraphic correlation on both local (field) and regional scale.

Globally, significant oil and gas reserves occur in so-called ‘barren red beds’. These sediments are generally deposited in a shallow to non-marine environment under arid (desert) climate conditions. In terrestrial basins, biostratigraphic analysis of plant microfossils (pollen and spores) is often effective in constraining static geological models. Unfortunately, such organic-walled microfossils are not preserved in red bed deposits due to oxidation, hampering stratigraphic correlation on both local (field) and regional scale. Although red beds occur throughout the geological timescale, examples with an economic interest are the Late Carboniferous, Permian and Early Triassic of Europe (Barren Measures, Rotliegendes, Bunter − Doornenbal and Stevenson, 2010), the Triassic of the United States, and the Permo-Carboniferous of the Middle East (Melvin & Sprague, 2006). Here, for the first time, we apply biogenic silica microfossils as a stratigraphic tool in the Permo-Carboniferous red bed sequences in the Southern North Sea. The combination of their qualitative occurrence, cyclic abundance patterns, and stable isotopic data provides the possibility to improve existing regional geological correlations, position regional unconformities, and to refine reservoir architecture models. We have applied the biogenic silica stratigraphy in two representative case studies in the Upper Rotliegend in the Southern North Sea Basin. The first example focuses on refining the basin infill model of the Upper Rotliegend and the second on detecting the position of the Base Permian Unconformity (BPU). Both aspects are critical for E&P activities in the Southern North Sea but are notoriously difficult to determine due to a lack of effective correlation tools in the red bed deposits. Permo-Carboniferous red beds in

A suite of organic geochemical, micropaleontological and palynological proxies was applied to sediments from Southwest Florida, to study the Holocene environmental changes associated with sea-level rise. Sediments were recovered from Hillsborough Bay, part of Tampa Bay, and studied using biomarkers, pollen, organic-walled dinoflagellate cysts and diatoms. Analyses show that the site flooded around 7.5 ka as a consequence of Holocene transgression, progressively turning a fresh/brackish marl-marsh into a shallow, restricted marine environment. Immediately after the marine transgression started, limited water circulation and high amounts of runoff caused stratification of the water column. A shift in dinocysts and diatom assemblages to more marine species, increasing concentrations of marine biomarkers and a shift in the Diol Index indicate increasing salinity between 7.5 ka and the present, which is likely a consequence of progressing sea-level rise. Reconstructed sea surface temperatures for the past 4 kyrs are between 25 and 26 ° C, and indicate stable temperatures during the Late Holocene. A sharp increase in sedimentation rate in the top ∼50 cm of the core is attributed to human impact. The results are in agreement with parallel studies from the area, but this study further refines the environmental reconstructions having the advantage of simultaneously investigating changes in the terrestrial and marine environment. © 2009 Elsevier Ltd.

Permo-Carboniferous sandstones are important reservoir rocks for natural gas in the Southern North Sea basin. This is a mature area which makes tools for reservoir characterization and well to well correlation important for field optimalisation and ongoing exploration activities. Within the Permo-Carboniferous sandstone reservoirs of the Dutch on- and offshore there are two key questions which still need to be resolved. One regards the geological model for the basin infill, another is the detection of the Base Permian Unconformity (BPU), an important regional unconformity. Biostratigraphy is classically used to address these problems. As the traditional microfossil groups are absent in the Permo-Carboniferous redbed deposits, the application of biostratigraphy is seriously hampered. In this study, we present a new biostratigraphical tool based on biogenic silica microfossils (BSPs). This fossil group consists of siliceous plant remains which are preserved even under extreme oxidizing conditions. BSPs are present in the Permo-Carboniferous redbed sequences and are now for the first time used for biostratigraphical correlations. This new tool holds great potential for independent chronostratigraphical correlations in economically important redbed deposits worldwide. In this study the initial results from a case study in the Southern North Sea basin will be presented.

This compilation lists the common diatoms of the Order Centrales and the Family Fragilariaceae from various freshwater environments in the Netherlands. The studied material consists of water samples and modern to Holocene sediment samples of at least 15 locations in the Netherlands. A total of 91 diatom taxa from 27 genera were recognized as being common and were documented on light micrographs. Information on the taxonomy, ecology and geographical distribution of all taxa is also provided. © 2010 J. Cramer in der Gebrüder Borntraeger Verlagsbuchhandlung.

Marine Quaternary deposits, here named the Store Koldewey Formation, are found at ~120m above sea level in northeast Greenland (76°N). The sequence is referred to the Olduvai normal polarity subchron at 1.95-1.78Ma BP based on palaeomagnetic studies (palaeomagnetically reversed), amino acid epimerization ratios and evidence from marine and non-marine fossils. The sediments and the fauna show that the sequence was deposited on a mid or inner shelf, and some elements of the marine mollusc and foraminiferal assemblages indicate water temperatures between -1 and +1°C and seasonal sea ice cover during deposition. Mean summer air temperatures were around 6°C higher than at present, as demonstrated by the occurrence of southern extralimital terrestrial species. Well-preserved remains of land plants indicate that the adjacent land area was dominated by sub-arctic forest-tundra with the trees Larix and Betula, shrubs, herbs and mosses. Most of the species represented as fossils have recent circumpolar geographical ranges. An extinct brachiopod species and an extinct gastropod species have been found, but the other macrofossils are referred to extant species. The brachiopod is erected as a new genus and species, Laugekochiana groenlandica. Correlation of the Koldewey Formation with the ile de France Formation farther to the north is suggested. Member A of the Kap Kobenhavn Formation in North Greenland is referred to the Late Pliocene, whereas Member B of the Kap Kobenhavn Formation is suggested to be slightly older than the Store Koldewey Formation. © 2010 The Authors, Journal compilation © 2010 The Boreas Collegium.

The Kap Mackenzie area on the outer coast of northeast Greenland was glaciated during the last glacial stage, and pre-Holocene shell material was brought to the area. Dating of marine shells indicates that deglaciation occurred in the earliest Holocene, before 10800cal. a BP. The marine limit is around 53m a.s.l. In the wake of the deglaciation, a glaciomarine fauna characterized the area, but after c. one millennium a more species-rich marine fauna took over. This fauna included Mytilus edulis and Mysella sovaliki, which do not live in the region at present; the latter is new to the Holocene fauna of northeast Greenland. The oldest M. edulis sample is dated to c. 9500cal. a BP, which is the earliest date for the species from the region and indicates that the Holocene thermal maximum began earlier in the region than previously documented. This is supported by driftwood dated to c. 9650cal. a BP, which is the earliest driftwood date so far from northeastern Greenland and implies that the coastal area was at least partly free of sea ice in summer. As indicated by former studies, the Storegga tsunami hit the Kap Mackenzie area at c. 8100cal. a BP. Loon Lake, at 18m a.s.l., was isolated from the sea at c. 6200cal. a BP, which is distinctly later than expected from existing relative sea-level curves for the region. © 2010 The Authors, Journal compilation © 2010 The Boreas Collegium.

Late Carboniferous to Middle Permian rocks resting on the Base Permian Unconformity in the Netherlands are of great economic significance. The Rotliegend rock sequences contain the most important gas reservoirs of the Netherlands, the Slochteren sanstones. However, the Rotliegend reservoir rocks are typically barren of any fossils, including palynomophs, which hampers stratigraphic control and correlation of these rocks. In a recent attempt of re-evaluation the barrenness of the Rotliegend, siliceous microfossils, referred to as biogenic silica particles (BSPs), in considerable morphological diversity could be extracted from these rocks. We applied a three-step approach to prepare BSP-containing microscopic slides from Rotliegend samples: (1) pre-flotation treatments aiming at the removal of large particles, organic matter, carbonate and clay, (2) repeated flotation steps in order to extract and concentrate BSPs, and (3) slide preparation using Naphrax™ as mounting medium. Many of the newly discovered siliceous microfossils resemble plant stones, so-called phytoliths, tiny silica bodies of various shape and size that are incorporated as structural elements in the roots, stems, and leafs of modern plants. Major plant groups like the gymnosperms, lycopods and ferns existed already by the end of the Devonian which might imply that these early land plants have also formed phytoliths in their tissues. The here reported BSPs constitute only the second evidence of phytolith-like siliceous microfossils from the Paleozoic. The newly extracted microfossils may provide a tool for subdividing and correlating Rotliegend rock successions. In order to test this hypothesis, Permo -Carboniferous rocks from various wells in the Netherlands were studied. Biogenic silica particles (BSPs) could be extracted from all studied wells and lithostratigraphic units. However, the total BSP abundance in the single samples considerably varies. A total of 22 BSPs with significant morphological differences could be hitherto identified. BSP assemblages in the Rotliegend are currently examined to determine how they can provide information on stratigraphy. The examined BSP-based biostratigraphic approaches include first and last occurrence dates and variability in the down-core abundance patterns. If the stratigraphic importance of BSPs could be confirmed in the ongoing studies, BSPs will provide a new tool for subdividing and correlating the mostly barren Rotliegend sequences.

Late Carboniferous to Early Permian clastic rocks of the Unayzah resting on the Hercynian Unconformity surface in Saudi Arabia, are of great economic significance, bearing significant quantities of gas and oil. The Unayzah reservoir sequences are often barren of fauna and flora which limits independent biostratigraphic control and well correlation. The presence of newly discovered siliceous microfossils may provide a tool for subdividing and correlating these rock successions. These siliceous microfossils may constitute phytoliths, microscopic silica bodies of various shape and size that form in the cells of roots, stems and leaves of plants. As major plant groups like gymnosperms, lycopods and ferns already existed by the end of the Devonian, one might expect that these early land plants also formed phytoliths in their tissues. Following decay of the plant, the silica bodies may become part of the sedimentary record. In order to test this hypothesis Permo-Carboniferous rocks from 12 wells, distributed over a large geographic area in Saudi Arabia, were studied. Biogenic silica particles (BSPs) were found in all studied wells and lithostratigraphic units. A total of 14 BSPs with some significant morphological differences were identified and described. BSP assemblages are currently being studied to determine whether they can provide information on facies, paleoclimate or stratigraphy. The fact that almost all BSP species were found in all lithostratigraphic units studied suggests that subdivision of the sedimentary sequences based on conventional first and last occurrence datums of BSPs, is not promising. On the other hand, BSPs show distinct abundance patterns that may be of stratigraphic importance. The sample collection from the Unayzah succession has recently been extended in order to enlarge the areal and stratigraphic coverage. If the outlined studies are successful, BSPs may provide a new tool for subdividing and correlating terrestrial rock sequences that are often barren of microfossils, including palynomorphs.

The Rauer Group is an archipelago in Prydz Bay, East Antarctica. The ice-free islands and the surrounding shallow marine areas provide valuable archives for the reconstruction of the late Pleistocene and Holocene environmental and climatic history of the region. Two sediment records from two marine inlets of Rauer Group have been studied for their sedimentological, geochemical, and biological characteristics. Radiocarbon ages from one of the inlets indicate ice-free conditions within the last glacial cycle, probably during the second half of Marine Isotope Stage 3. Subsequent ice sheet coverage of Rauer Group during the Last Glacial Maxiumum (LGM) can be inferred from a till layer recovered in one of the basins. The inlets became ice-free prior to 11,200. cal yr BP, when biogenic sedimentation started. Deglacial processes in the catchments, however, influenced the inlets until ~. 9200. cal yr BP as evidenced by the input of minerogenic material. Marine productivity under relatively open water conditions indicates an early Holocene climate optimum until 8200. cal yr BP, which is followed by a cooler period with increased sea ice. Warmer conditions are inferred for the mid Holocene, when both basins experienced an input of freshwater between ~. 5700-3500. cal yr BP, probably due to ice-sheet melting and increased precipitation on the islands. Neoglacial cooling in the late Holocene since c. 3500. cal yr BP is reflected by an increase in sea ice in both inlets. © 2010 Elsevier B.V.

We present a case study of the development of Sacrower See, a stratified, eutrophic lake in northeastern Germany, over the past 13,000 years. Total epilimnetic phosphorus (TP) concentrations were reconstructed quantitatively using a diatom-TP transfer function. Fossil chironomid assemblages were used to support the trophic reconstruction and helped assessing past hypolimnetic oxygen availability. The results indicate eutrophic and anoxic conditions during the Younger Dryas cold period (∼12,700-11,600 cal. BP) preceding the present interglacial. Throughout the early and mid-Holocene (∼11,600-4000 cal. BP) stable oligo- to mesotrophic conditions with diatom-inferred TP values of ∼20 μg L-1 prevailed. First evidence of increasing Holocene TP is recorded at ∼3500 cal. BP associated with Bronze Age human impact and for the past 900 years diatoms indicate increasing TP values of 30-60 μg L-1. During the early Holocene and the past two millennia chironomids indicated anoxic hypolimnetic conditions. The chironomid fauna is considered typical of oligo- to mesotrophic lakes. As a consequence of strongly increased primary production the hypolimnion of Sacrower See became anoxic again during the past 140 years. Our results indicate that highly productive eutrophic conditions can exist prior to cultural eutrophication. At Sacrower See the shift from eutrophic conditions in the Lateglacial to oligo-mesotrophic conditions in the early and mid-Holocene was associated with the climatic warming at the Younger Dryas/Holocene transition. The high productive state during the cold Younger Dryas is associated with changes in seasonality: the prolonged winters caused longer ice cover, stronger stratification, anoxia in the hypolimnion, and consequent internal phosphorus loading. During the warm Holocene, however, hypolimnetic anoxia and internal phosphorus loading decreased significantly, resulting in a substantially lower productivity.

The coastal wetland ecosystems in Florida are highly sensitive to changes in freshwater budget, which is driven by regional sea surface temperature, tropical storm activity, and the El Nino-Southern Oscillation (ENSO). Although studying Florida wetlands is pivotal to the understanding of these interacting climate systems, wetland dynamics have been severely altered by recent land use and drainage activities. To gather insights into the natural variability of the coastal ecosystems in Florida versus the effects of anthropogenic impact in the area, we present a 300-year record of changes in the hydrological cycle from a shallow subtropical estuary (Rookery Bay) on the western shelf of Florida, Gulf of Mexico. Palynological (pollen and organic-walled dinoflagellate cysts), diatom, and sedimentological analyses of a sediment core reveal significant changes in past runoff and wetland development. The onset and development of human impact in Florida are evident from high influx of Ambrosia pollen at about A.D. 1900, indicative of land clearance and disturbed conditions. To date, this is the southernmost record of Ambrosia increase related to human impact in the United States. Wetland drainage and deforestation since A.D. 1900 are evident from the reduced freshwater wetland and pine vegetation, and lower abundances of phytoplankton species indicative of lagoonal and brackish conditions. High runoff after A.D. 1900 relates to increased erosionand may correspondingly reflect higher impact from hurricane landfalls in SW Florida. Several phases with high siliciclastic input and greater wetland pollen abundance occur that predate the human impact period. These phases are interpreted as periods with higher runoff and are likely related to regional longer-term climate variability. Copyright 2008 by the American Geophysical Union.

Two sediment cores of 70 and 252 cm length were recovered from Hjort Sø, a small lake on Store Koldewey, Northeast Greenland, and studied with a multidisciplinary approach in order to reconstruct the local environmental history and to test the relevance of proxies for paleoenvironmental information. The basal sediments from the longer core are dominated by clastic matter, which was likely deposited during deglaciation of the lake basin. These clastic sediments are overlain by gyttja, which is also present throughout the shorter core. AMS radiocarbon dating was conducted on plant macrofossils of 11 samples from the gyttja in both cores. A reliable chronology was established for both cores, which dated the onset of organic accumulation at 9,500 cal. year BP. The Holocene temperature development, with an early to mid Holocene thermal maximum, is best reflected in the grain-size composition. Nutrient availability was apparently low during the early Holocene and led to low productivity in the lake and its vicinity. From ca. 7,000 cal. year BP, productivity in the lake increased significantly, probably induced by external nutrient input from goose excrements. From this time, micro- and macro-fossil remains reflect relatively well the climate history of East Greenland, with a cooling during the middle Holocene, the medieval warming, and the Little Ice Age. The amount of organic matter in the sequence seems to be more affected by lake ice cover or by nutrient supply from the catchment than by temperature changes. The record from Hjort Sø thus reveals the difficulties in interpreting sedimentary records from high arctic regions. © 2007 Springer Science+Business Media B.V.

(Loginova, Lupikina et Khurs.) Flower, Ozornina & A.I.Kuzmina, has been studied in the past years mainly from three regions: the Lake Baikal region (Flower et al. 1998, Genkal et al. 2001), Lake El’gygytgyn (Cremer & Van de Vijver 2006, Cremer et al. 2005), and Lake Jana in the Verkhojansk Mountains (Stachura-Suchoples 2006). These studies demonstrated that

Lateglacial environments at Hijkermeer, northwest Netherlands, were reconstructed by means of chironomid, diatom and pollen analyses. Diatom assemblages indicate that Hijkermeer was a shallow, oligo- to mesotrophic lake during this period. Pollen assemblages reflect the typical northwest European Lateglacial vegetation development and provide an age assessment for the record from the beginning of the Older Dryas (ca 14 000 calibrated 14C yr BP) into the early Holocene (to ca 10 700 calibrated 14C yr BP). The chironomid record is characterized by several abrupt shifts between assemblages typically found in mid-latitude subalpine to alpine lakes and assemblages typical for lowland environments. Based on the chironomid record, July air temperatures were reconstructed using a chironomid-temperature transfer-function from central Europe. Mean July air temperatures of ca 14.0-16.0 °C are inferred before the Older Dryas, of ca 16.0-16.5 °C during most of the Allerod, of ca 13.5-14.0 °C during the Younger Dryas, and of ca 15.5-16.0 °C during the early Holocene. Two centennial-scale decreases in July air temperature were reconstructed during the Lateglacial interstadial which are correlated with Greenland Interstadial events (GI)-1d and -1b. The results suggest that vegetation changes in the Netherlands may have been promoted by the cooler climate during GI-1d, immediately preceding the Older Dryas biozone, and GI-1b. The Hijkermeer chironomid-inferred temperature record shows a similar temperature development as the Greenland ice core oxygen isotope records for most of the Lateglacial and a good agreement with other temperature reconstructions available from the Netherlands. This suggests that chironomid-based temperature reconstruction can be successfully implemented in the Northwest European lowlands and that chironomids may provide a useful alternative to oxygen isotopes for correlating European lake sediment records during the Lateglacial. © 2007 Elsevier Ltd. All rights reserved.

We report a centennial-scale warming event between 8600 and 8400 cal BP from Amery Oasis, East Antarctica, that is documented by the geochemical record in a lacustrine sediment sequence. The organic carbon content, the C/S ratio, and the sedimentation rate in this core have distinctly elevated values around 8500 y ago reflecting relatively warm and ice-free conditions that led to well-ventilated conditions in the lake and considerable sedimentation of both autochthonous and allochthonous organic matter on the lake bottom. This abrupt warming event occurred concurrently with reported warm climatic conditions in the Southern Ocean while the climate in central East Antarctic remained cold. The comparison of the spatial and temporal variability of warm climatic periods documented in various terrestrial, marine, and glacial archives from East Antarctica elucidates the uniqueness of the centennial-scale warming event in the Amery Oasis. We also discuss a possible correlation of the Amery warming event with the abrupt climatic deterioration around 8200 cal BP on the Northern Hemisphere. © 2007 Elsevier Ltd. All rights reserved.

Radok Lake in Amery Oasis, East Antarctica, has a water depth of ca. 360 m, making it the deepest non-subglacial lake in Antarctica. Limnological analyses revealed that the lake had, despite a 3 m thick ice cover, a completely mixed water column during austral summer 2001/2002. High oxygen contents, low ion concentrations, and lack of planktonic diatoms throughout the water column indicate that Radok Lake is ultra-oligotrophic today. The late glacial and postglacial lake history is documented in a succession of glacial, glaciolimnic, and limnic sediments at different locations in the lake basin. The sediments record regional differences and past changes in allochthonous sediment supply and lake productivity. However, the lack of age control on these changes, due to extensive sediment redeposition and the lack of applicable dating methods, excluded Radok Lake sediments for advanced paleoenvironmental reconstructions.

The physico-chemical characteristics and the planktonic diatom flora were studied in high arctic Loon Lake (Geographical Society O, East Greenland). Loon Lake is a cold, monomictic, alkaline, low conductive and likely oligotrophic lake with a maximum water depth of 11.70 m and a low diversity of planktonic diatoms. In summer 2003, the lake-water diatom community consisted of three taxa: frustules belonging to the morphologically highly variable Cyclotella ocellata-polymorpharossii-tripartita-complex were most abundant, and both Discostella pseudostelligera and Fragilaria tenera were of minor importance. The morphological variability of the three diatom taxa is documented by light micrographs.