Vegetation and glacier dynamics are sensitive to summer (not winter) warming and the evidence for larch refugia in the ‘Northern Pole of Cold’ inferred from sedimentary ancient DNA and geochemistry

Climate seasonality critically influences the functioning and dynamics of ecosystems in continental areas. The ecological importance of winter temperatures on high-latitude vegetation changes has recently been argued to be largely overlooked in comparison to summer temperatures. The Oymyakon region from eastern Siberia, with its strong continentality of extremely cold winters and moderately warm summers, is ideally suited to study the response of past vegetation to seasonal temperature changes based on long ecological time-series. However, few paleorecords are available from this area. The history of regional glacial activity and potential plant refugia since Marine Isotope Stage (MIS) 3 is not well understood. Here, we present geochemical and plant DNA metabarcoding records retrieved from a sediment core from Lake Ulu in the Oymyakon region, which provides detailed information on glacier and vegetation dynamics over the last 43 cal. ka BP. Our results suggest that glacial fluctuations were primarily driven by summer insolation, and Lake Ulu was likely initiated by glacial retreat during MIS 3. The catchment experienced multiple glacial advance/retreat cycles until the Last Glacial Maximum, and the glaciers fully retreated by 20 cal. ka BP. In addition, a tundra-steppe landscape dominated by Dryas, Papaver, Saliceae, and Anthemideae occupied the catchment for most of the time and began to collapse around 19 cal. ka BP following the expansion of trees and shrubs such as Larix, Betula, Alnus, and Vaccinium. Postglacial plant assemblages in the Oymyakon region exhibit a high sensitivity to summer temperature variations, with minimal impact from winter temperatures. This can be explained by the dominance of summer insolation amplitude, extreme continentality, extended plant growing season, and plant genetic adaptation to cold. Notably, our ancient DNA record show the earliest postglacial expansion of larch in eastern Siberia (around 18.6 cal. ka BP), which is likely related to the presence of local refugia. This implies that the Oymyakon region may be one of the earliest sources for larch recolonization and that more research should be implemented to provide insights into larch expansion and migration, and to better predict the future scenarios for Siberian larch forests

Genetic and morphologic determination of diatom community composition in surface sediments from glacial and thermokarst lakes in the Siberian Arctic

Lakes cover large parts of the climatically sensitive Arctic landscape and respond rapidly to environmental change. Arctic lakes have different origins and include the predominant thermokarst lakes, which are small, young and highly dynamic, as well as large, old and stable glacial lakes. Freshwater diatoms dominate the primary producer community in these lakes and can be used to detect biotic responses to climate and environmental change. We used specific diatom metabarcoding on sedimentary DNA, combined with next-generation sequencing and diatom morphology, to assess diatom diversity in five glacial and 15 thermokarst lakes within the easternmost expanse of the Siberian treeline ecotone in Chukotka, Russia. We obtained 163 verified diatom sequence types and identified 176 diatom species morphologically. Although there were large differences in taxonomic assignment using the two approaches, they showed similar high abundances and diversity of Fragilariceae and Aulacoseiraceae. In particular, the genetic approach detected hidden within-lake variations of fragilarioids in glacial lakes and dominance of centric Aulacoseira species, whereas Lindavia ocellata was predominant using morphology. In thermokarst lakes, sequence types and valve counts also detected high diversity of Fragilariaceae, which followed the vegetation gradient along the treeline. Ordination analyses of the genetic data from glacial and thermokarst lakes suggest that concentrations of sulfate, an indicator of the activity of sulfate-reducing microbes under anoxic conditions, and bicarbonate, which relates to surrounding vegetation, have a significant influence on diatom community composition. For thermokarst lakes, we also identified lake depth as an important variable, but sulfate best explains diatom diversity derived from genetic data, whereas bicarbonate best explains the data from valve counts. Higher diatom diversity was detected in glacial lakes, most likely related to greater lake age and different edaphic settings, which gave rise to diversification and endemism. In contrast, small, dynamic thermokarst lakes are inhabited by stress-tolerant fragilarioids and are related to different vegetation types along the treeline ecotone. Our study demonstrated that genetic investigations of lake sediments can be used to interpret climate and environmental responses of diatoms. It also showed how lake type affects diatom diversity, and that such genetic analyses can be used to track diatom community changes under ongoing warming in the Arctic

Long-term thermokarst lake development and internal ecological feedbacks: A new reconstruction from Lake Satagay (Yakutia, Siberia)

The permafrost-shaped landscape of Central Yakutia is particularly rich in thermokarst lakes, which provide important cultural and ecosystem services to the local population. Climate warming and an intensification of agriculture in alaas systems (i.e. mostly drained basins of large thaw lakes formed during the early Holocene under warm climatic conditions) in the Central Yakutian Lowlands may lead to pronounced changes in water resources, water quality, nutrient loading and biodiversity. This could in turn threaten the livelihoods of affected communities, who depend on functional alaas ecosystems. To better foresee potential future impacts of environmental changes on internal lake ecological processes, it is important to gain a better understanding of how thermokarst lakes reacted to such changes in the past. Here, we present a new paleoenvironmental reconstruction of ecological changes within Lake Satagay (N 63.078, E 117.998, Nyurbinsky District), covering the last ca. 10,800 years. We use sedimentological and XRF-derived geochemical parameters, in addition to the metabarcoding of sedimentary ancient DNA (sedDNA) for diatoms and aquatic plants, and microscopic diatom analyses, to evaluate sedimentological and biodiversity shifts throughout the Holocene. Our study revealed 53 diatom DNA sequence types and 53 species morphologically. High distributions of Stephanodiscus and Fragilaria, among multiple other diatom genera in the early Holocene, indicate that initial formation of this typical alaas lake occurred earlier than expected (i.e. before 10,800 BP). In recent millennia diatom abundance decreased and their community is almost exclusively composed of Pseudostaurosira and Fragilaria. Composition of aquatic plants show an overall dominance of Ceratophyllaceae and strong fluctuations in Potamogetonaceae likely related to lake level and water chemical changes. All proxies investigated support that lake conditions and biotic composition has been resilient since 4,000 BP, but youngest samples since 47 BP indicate that land use influence has been crucial for the lake quality. This study represents a step towards a better understanding of climate and human-impacted alaas lake development and its consequences for their ecosystem services in eastern Siberia in the near future

Clinical and neurocognitive outcome in symptomatic isovaleric acidemia

<p>Abstract</p> <p>Background</p> <p>Despite its first description over 40 years ago, knowledge of the clinical course of isovaleric acidemia (IVA), a disorder predisposing to severe acidotic episodes during catabolic stress, is still anecdotal. We aimed to investigate the phenotypic presentation and factors determining the neurological and neurocognitive outcomes of patients diagnosed with IVA following clinical manifestation.</p> <p>Methods</p> <p>Retrospective data on 21 children and adults with symptomatic IVA diagnosed from 1976 to 1999 were analyzed for outcome determinants including age at diagnosis and number of catabolic episodes. Sixteen of 21 patients were evaluated cross-sectionally focusing on the neurological and neurocognitive status. Additionally, 155 cases of patients with IVA published in the international literature were reviewed and analyzed for outcome parameters including mortality.</p> <p>Results</p> <p>57% of study patients (12/21) were diagnosed within the first weeks of life and 43% (9/21) in childhood. An acute metabolic attack was the main cause of diagnostic work-up. 44% of investigated study patients (7/16) showed mild motor dysfunction and only 19% (3/16) had cognitive deficits. No other organ complications were found. The patients' intelligence quotient was not related to the number of catabolic episodes but was inversely related to age at diagnosis. In published cases, mortality was high (33%) if associated with neonatal diagnosis, following manifestation at an average age of 7 days.</p> <p>Conclusions</p> <p>Within the group of "classical" organic acidurias, IVA appears to be exceptional considering its milder neuropathologic implications. The potential to avoid neonatal mortality and to improve neurologic and cognitive outcome under early treatment reinforces IVA to be qualified for newborn screening.</p

Diatom responses and geochemical feedbacks to environmental changes at Lake Rauchuagytgyn (Far East Russian Arctic)

This study is based on multiproxy data gained from a 14C-dated 6.5 m long sediment core and a 210Pb-dated 23 cm short core retrieved from Lake Rauchuagytgyn in Chukotka, Arctic Russia. Our main objectives are to reconstruct the environmental history and ecological development of the lake during the last 29 kyr and to investigate the main drivers behind bioproduction shifts. The methods comprise age-modeling, accumulation rate estimation, and light microscope diatom species analysis of 74 samples, as well as organic carbon, nitrogen, and mercury analysis. Diatoms have appeared in the lake since 21.8 ka cal BP and are dominated by planktonic Lindavia ocellata and L. cyclopuncta. Around the Pleistocene–Holocene boundary, other taxa including planktonic Aulacoseira, benthic fragilarioid (Staurosira), and achnanthoid species increase in their abundance. There is strong correlation between variations of diatom valve accumulation rates (DARs; mean 176.1×109 valves m2 a1), organic carbon accumulation rates (OCARs; mean 4.6 g m−2 a−1), and mercury accumulation rates (HgARs; mean 63.4 µg m−2 a−1). We discuss the environmental forcings behind shifts in diatom species and find moderate responses of key taxa to the cold glacial period, postglacial warming, the Younger Dryas, and the Holocene Thermal Maximum. The short-core data likely suggest recent change of the diatom community at the beginning of the 20th century related to human-induced warming but only little evidence of atmospheric deposition of contaminants. Significant correlation between DAR and OCAR in the Holocene interglacial indicates within-lake bioproduction represents bulk organic carbon deposited in the lake sediment. During both glacial and interglacial episodes HgAR is mainly bound to organic matter in the lake associated with biochemical substrate conditions. There were only ambiguous signs of increased HgAR during the industrialization period. We conclude that if increased short-term emissions are neglected, pristine Arctic lake systems can potentially serve as long-term CO2 and Hg sinks during warm climate episodes driven by insolation-enhanced within-lake primary productivity. Maintaining intact natural lake ecosystems should therefore be of interest to future environmental policy

Transfer of manualized Short Term Psychodynamic Psychotherapy (STPP) for social phobia into clinical practice: study protocol for a cluster-randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Psychodynamic psychotherapy is frequently applied in the treatment of social phobia. Nevertheless, there has been a lack of studies on the transfer of manualized treatments to routine psychodynamic practice. Our study is the first one to examine the effects of additional training in a manualized Short Term Psychodynamic Psychotherapy (STPP) procedure on outcome in routine psychotherapy for social phobia. This study is an extension to a large multi-site RCT (N = 512) comparing the efficacy of STPP to Cognitive-Behavioral Therapy (CBT) of Social Phobia.</p> <p>Methods/Design</p> <p>The manualized treatment is designed for a time limited approach with 25 individual sessions of STPP over 6 months. Private practitioners will be randomized to training in manualized STPP vs. treatment as usual without a specific training (control condition). We plan to enrol a total of 105 patients (84 completers). Assessments will be conducted before treatment starts, after 8 and 15 weeks, after 25 treatment sessions, at the end of treatment, 6 months and 12 months after termination of treatment. The primary outcome measure is the Liebowitz Social Anxiety Scale. Remission from social phobia is defined scoring with 30 or less points on this scale.</p> <p>Discussion</p> <p>We will investigate how the treatment can be transferred from a controlled trial into the less structured setting of routine clinical care. This question represents Phase IV of psychotherapy research. It combines the benefits of randomized controlled and naturalistic research. The study is genuinely designed to promote faster and more widespread dissemination of effective interventions. It will answer the questions whether manualized STPP can be implemented into routine outpatient care, whether the new methods improve treatment courses and outcomes and whether treatment effects reached in routine psychotherapeutic treatments are comparable to those of the controlled, strictly manualized treatment of the main study.</p> <p>Trial Registration</p> <p>German Clinical Trials Register (DRKS) DRKS00000570</p

Efficacy and outcome of expanded newborn screening for metabolic diseases - Report of 10 years from South-West Germany *

<p>Abstract</p> <p>Background</p> <p>National newborn screening programmes based on tandem-mass spectrometry (MS/MS) and other newborn screening (NBS) technologies show a substantial variation in number and types of disorders included in the screening panel. Once established, these methods offer the opportunity to extend newborn screening panels without significant investment and cost. However, systematic evaluations of newborn screening programmes are rare, most often only describing parts of the whole process from taking blood samples to long-term evaluation of outcome.</p> <p>Methods</p> <p>In a prospective single screening centre observational study 373 cases with confirmed diagnosis of a metabolic disorder from a total cohort of 1,084,195 neonates screened in one newborn screening laboratory between January 1, 1999, and June 30, 2009 and subsequently treated and monitored in five specialised centres for inborn errors of metabolism were examined. Process times for taking screening samples, obtaining results, initiating diagnostic confirmation and starting treatment as well as the outcome variables metabolic decompensations, clinical status, and intellectual development at a mean age of 3.3 years were evaluated.</p> <p>Results</p> <p>Optimal outcome is achieved especially for the large subgroup of patients with medium-chain acyl-CoA dehydrogenase deficiency. Kaplan-Meier-analysis revealed disorder related patterns of decompensation. Urea cycle disorders, organic acid disorders, and amino acid disorders show an early high and continuous risk, medium-chain acyl-CoA dehydrogenase deficiency a continuous but much lower risk for decompensation, other fatty acid oxidation disorders an intermediate risk increasing towards the end of the first year. Clinical symptoms seem inevitable in a small subgroup of patients with very early disease onset. Later decompensation can not be completely prevented despite pre-symptomatic start of treatment. Metabolic decompensation does not necessarily result in impairment of intellectual development, but there is a definite association between the two.</p> <p>Conclusions</p> <p>Physical and cognitive outcome in patients with presymptomatic diagnosis of metabolic disorders included in the current German screening panel is equally good as in phenylketonuria, used as a gold standard for NBS. Extended NBS entails many different interrelated variables which need to be carefully evaluated and optimized. More reports from different parts of the world are needed to allow a comprehensive assessment of the likely benefits, harms and costs in different populations.</p

Paleo-Ecology of the Yedoma Ice Complex on Sobo-Sise Island (Eastern Lena Delta, Siberian Arctic)

Late Pleistocene permafrost of the Yedoma type constitutes a valuable paleo-environmental archive due to the presence of numerous and well-preserved floral and faunal fossils. The study of the fossil Yedoma inventory allows for qualitative and quantitative reconstructions of past ecosystem and climate conditions and variations over time. Here, we present the results of combined paleo-proxy studies including pollen, chironomid, diatom and mammal fossil analyses from a prominent Yedoma cliff on Sobo-Sise Island in the eastern Lena Delta, NE Siberia to complement previous and ongoing paleo-ecological research in western Beringia. The Yedoma Ice Complex (IC) cliff on Sobo-Sise Island (up to 28 m high, 1.7 km long) was continuously sampled at 0.5 m resolution. The entire sequence covers the last about 52 cal kyr BP, but is not continuous as it shows substantial hiatuses at 36–29 cal kyr BP, at 20–17 cal kyr BP and at 15–7 cal kyr BP. The Marine Isotope Stage (MIS) 3 Yedoma IC (52–28 cal kyr BP) pollen spectra show typical features of tundra–steppe vegetation. Green algae remains indicate freshwater conditions. The chironomid assemblages vary considerably in abundance and diversity. Chironomid-based TJuly reconstructions during MIS 3 reveal warmer-than-today TJuly at about 51 cal kyr BP, 46-44 and 41 cal kyr BP. The MIS 2 Yedoma IC (28–15 cal kyr BP) pollen spectra represent tundra-steppe vegetation as during MIS 3, but higher abundance of Artemisia and lower abundances of algae remains indicate drier summer conditions. The chironomid records are poor. The MIS 1 (7–0 cal kyr BP) pollen spectra indicate shrub-tundra vegetation. The chironomid fauna is sparse and not diverse. The chironomid-based TJuly reconstruction supports similar-as-today temperatures at 6.4–4.4 cal kyr BP. Diatoms were recorded only after about 6.4 cal kyr BP. The Sobo-Sise Yedoma record preserves traces of the West Beringian tundra-steppe that maintained the Mammoth fauna including rare evidence for woolly rhinoceros’ presence. Chironomid-based TJuly reconstructions complement previous plant-macrofossil based TJuly of regional MIS 3 records. Our study from the eastern Lena Delta fits into and extends previous paleo-ecological Yedoma studies to characterize Beringian paleo-environments in the Laptev Sea coastal region