scholarly journals Amplified bioproductivity during Transition IV (332 000–342 000 yr ago): evidence from the geochemical record of Lake El'gygytgyn

2012 ◽  
Vol 8 (6) ◽  
pp. 5341-5358 ◽  
Author(s):  
L. Cunningham ◽  
H. Vogel ◽  
V. Wennrich ◽  
O. Juschus ◽  
N. Nowaczyk ◽  
...  
Keyword(s):  
Biogenic Silica ◽  
Ice Cores ◽  
Arctic Region ◽  
Climatic Conditions ◽  
The Arctic ◽  
Significant Shift ◽  
Geochemical Parameters ◽  
Lake El’Gygytgyn ◽  
Arctic Russia

Abstract. To date, terrestrial archives of long-term climatic change within the arctic region have widely been restricted to ice cores from Greenland and, more recently, sediments from Lake El'gygytgyn in Northeast Arctic Russia. Sediments from this lake contain a paleoclimate record of glacial-interglacial cycles during the last three million years. Low resolution studies at this lake have suggested that changes observed during Transition IV are of greater amplitude than any observed since. In this study, geochemical parameters are used to infer past climatic conditions thus providing the first high resolution analyses of Transition IV from a terrestrial arctic setting. These results demonstrate that a significant shift in climate was subsequently followed by a rapid increase in biogenic silica production. Following this sharp increase, bioproductivity remained high, but variable, for over a thousand years. This study reveals differences in the timing and magnitude of change within the ratio of silica to titanium (Si/Ti) and biogenic silica (BSi) records that would not be apparent in lower resolution studies. This has significant implications for the increasingly common use of Si/Ti data as an alternative to traditional BSi measurements.

scholarly journals Amplified bioproductivity during Transition IV (332 000–342 000 yr ago): evidence from the geochemical record of Lake El'gygytgyn

2013 ◽  
Vol 9 (2) ◽  
pp. 679-686 ◽  
Author(s):  
L. Cunningham ◽  
H. Vogel ◽  
V. Wennrich ◽  
O. Juschus ◽  
N. Nowaczyk ◽  
...  
Keyword(s):  
Sharp Increase ◽  
Biogenic Silica ◽  
Ice Cores ◽  
Climatic Conditions ◽  
The Arctic ◽  
Significant Shift ◽  
Geochemical Parameters ◽  
Lake El’Gygytgyn ◽  
Arctic Russia

Abstract. To date, terrestrial archives of long-term climatic change within the Arctic have widely been restricted to ice cores from Greenland and, more recently, sediments from Lake El'gygytgyn in northeast Arctic Russia. Sediments from this lake contain a paleoclimate record of glacial-interglacial cycles during the last three million years. Low-resolution studies at this lake have suggested that changes observed during Transition IV (the transition from marine isotope stage (MIS) 10 to MIS 9) are of greater amplitude than any observed since. In this study, geochemical parameters are used to infer past climatic conditions thus providing the first high-resolution analyses of Transition IV from a terrestrial Arctic setting. These results demonstrate that a significant shift in climate was subsequently followed by a rapid increase in biogenic silica (BSi) production. Following this sharp increase, bioproductivity remained high, but variable, for over a thousand years. This study reveals differences in the timing and magnitude of change within the ratio of silica to titanium (Si/Ti) and BSi records that would not be apparent in lower resolution studies. This has significant implications for the increasingly common use of Si/Ti data as an alternative to traditional BSi measurements.

scholarly journals Palynological insights into global change impacts on Arctic vegetation, fire, and pollution recorded in Central Greenland ice

The Holocene ◽  
2019 ◽  
Vol 29 (7) ◽  
pp. 1189-1197 ◽  
Author(s):  
Sandra O Brugger ◽  
Erika Gobet ◽  
Thomas Blunier ◽  
César Morales-Molino ◽  
André F Lotter ◽  
...  
Keyword(s):  
Global Change ◽  
20Th Century ◽  
Anthropogenic Activities ◽  
Ice Core ◽  
Ice Cores ◽  
Arctic Region ◽  
Climatic Conditions ◽  
The Arctic ◽  
Arctic Vegetation ◽  
Ranunculus Acris

Arctic environments may respond very sensitively to ongoing global change, as observed during the past decades for Arctic vegetation. Only little is known about the broad-scale impacts of early and mid 20th-century industrialization and climate change on remote Arctic environments. Palynological analyses of Greenland ice cores may provide invaluable insights into the long-term vegetation, fire, and pollution dynamics in the Arctic region. We present the first palynological record from a Central Greenland ice core (Summit Eurocore ’89, 72°35’N, 37°38’W; the location of Greenland Ice Core Project GRIP) that provides novel high-resolution microfossil data on Arctic environments spanning AD 1730–1989. Our data suggest an expansion of birch woodlands after AD 1850 that was abruptly interrupted at the onset of the 20th century despite favorable climatic conditions. We therefore attribute this Betula woodland decline during the 20th century to anthropogenic activities such as sheep herding and wood collection in the sub-Arctic. First signs of coal burning activities around AD 1900 coincide with the onset of Arctic coal mining. The use of coal and fire activity increased steadily until AD 1989 resulting in microscopic-size pollution of the ice sheet. We conclude that human impact during the 20th century strongly affected (sub)-Arctic environments. Moreover, ecosystems have changed through the spread of adventive plant species (e.g. Ranunculus acris, Rumex) and the destruction of sparse native woodlands. We show for the first time that optical palynology allows paleoecological reconstructions in extremely remote sites >500 km from potential sources, if adequate methods are used.

scholarly journals Paleocene-Eocene volcanic segmentation of the Norwegian-Greenland seaway reorganized high-latitude ocean circulation

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jussi Hovikoski ◽  
Michael B. W. Fyhn ◽  
Henrik Nøhr-Hansen ◽  
John R. Hopper ◽  
Steven Andrews ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
High Latitude ◽  
Seismic Reflection ◽  
Arctic Region ◽  
Climatic Conditions ◽  
The Arctic ◽  
Early Eocene ◽  
Subaerial Exposure ◽  
Thermal Maximum ◽  
Volcanic Facies

AbstractThe paleoenvironmental and paleogeographic development of the Norwegian–Greenland seaway remains poorly understood, despite its importance for the oceanographic and climatic conditions of the Paleocene–Eocene greenhouse world. Here we present analyses of the sedimentological and paleontological characteristics of Paleocene–Eocene deposits (between 63 and 47 million years old) in northeast Greenland, and investigate key unconformities and volcanic facies observed through seismic reflection imaging in offshore basins. We identify Paleocene–Eocene uplift that culminated in widespread regression, volcanism, and subaerial exposure during the Ypresian. We reconstruct the paleogeography of the northeast Atlantic–Arctic region and propose that this uplift led to fragmentation of the Norwegian–Greenland seaway during this period. We suggest that the seaway became severely restricted between about 56 and 53 million years ago, effectively isolating the Arctic from the Atlantic ocean during the Paleocene–Eocene thermal maximum and the early Eocene.

scholarly journals High-time resolved radon-progeny measurements in the Arctic region (Svalbard Islands, Norway): results and potentialities

2017 ◽  
Author(s):  
Roberto Salzano ◽  
Antonello Pasini ◽  
Antonietta Ianniello ◽  
Mauro Mazzola ◽  
Rita Traversi ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Atmospheric Stability ◽  
Arctic Region ◽  
Climatic Conditions ◽  
The Arctic ◽  
Radon Emanation ◽  
Radon Progeny ◽  
Time Resolved ◽  
Scientific Challenge ◽  
The Arctic Region

Abstract. The estimation of radon progeny in the Arctic region represents a scientific challenge due to the required low limit of detection in consideration of the limited radon emanation associated with permafrost dynamics. This preliminary study highlighted, for the first time, the possibility to monitor radon progeny in the Arctic region with a higher time resolution. The composition of the radon progeny offered the opportunity to identify air masses dominated by long-range transport, in presence or not of near-constant radon progeny instead of long and short lived progenies. Furthermore, the different ratio between radon and thoron progenies evidenced the contributions of local emissions and atmospheric stability. Two different emanation periods were defined in accordance to the permafrost dynamics at the ground and several accumulation windows were recognized coherently to the meteo-climatic conditions occurring at the study site.

scholarly journals CEREBRAL ENERGY METABOLISM IN YOUNG PEOPLE DURING ADAPTATION TO THE CONDITIONS OF THE ARCTIC REGION

2019 ◽  
Vol 19 (2) ◽  
pp. 7-13
Author(s):  
N Anikina ◽  
A Gribanov ◽  
I Kozhevnikova ◽  
M Pankov ◽  
S Bagretsov
Keyword(s):  
Energy Consumption ◽  
Energy Metabolism ◽  
Young People ◽  
Left Hemisphere ◽  
Arctic Region ◽  
Climatic Conditions ◽  
Regulatory Mechanisms ◽  
The Arctic ◽  
Cerebral Energy Metabolism ◽  
The Arctic Region

Aim. The article deals with determining the features of cerebral energy metabolism in young people at different stages of adaptation in the Arctic region. Materials and methods. The level of permanent brain direct current potentials (DCP) was measured in 146 young people: 93 born and permanently living in the Arctic region and 53 migrants living in new climatic conditions for the first months. The study was conducted by using a “Neuro-KM” 12-channel hardware-software complex for the topographic mapping of brain electrical activity. DCP were recorded in the unipolar leads according to the 10-20 international system. Statistical processing of the data obtained was carried out with the software package SPSS-20 for Windows. Results. In young people permanently living in the Arctic region, we revealed functional asymmetry of the brain with right-hemisphere dominance in almost all leads. In migrants living in the climatic conditions of the Arctic region for the first months, we established high values of energy consumption and partial asymmetry of cerebral energy metabolism. Conclusion. Body functioning in the usual habitat is characterized by a stereotypical set of regulatory mechanisms. During adaptation, new ways of responding to changes in the environment are formed. The dominance of the right or left hemisphere occurs depending on the type of tasks. The analysis of interhemispheric asymmetry of energy consumption performed by using the method of brain mapping allows assessing the degree of dominance. The dominance of energy consumption in the left hemisphere may indicate a possible failure of adaptation mechanisms. Positive interhemispheric gradients indicate the correct performance of CNS regulatory mechanisms during adaptation to new environmental conditions

scholarly journals Seasonal and Decadal Variability of Atmosphere Pressure in Arctic, its Statistical and Temporal Analysis

2021 ◽  
Vol 24 (1) ◽  
pp. 57-73
Author(s):  
Константин Павлович Беляев ◽  
Гурий Михайлович Михайлов ◽  
Алексей Николаевич Сальников ◽  
Наталия Павловна Тучкова
Keyword(s):  
Decadal Variability ◽  
Diffusion Processes ◽  
Arctic Region ◽  
Temporal Analysis ◽  
The Arctic ◽  
State University ◽  
Main Research ◽  
Geophysical Interpretation ◽  
The Given

The paper analyzes the statistical and temporal seasonal and decadal variability of the atmospheric pressure field in the Arctic region of Russia. Schemes for the frequency analysis of probability transitions for characteristics of stochastic-diffusion processes were used as the main research method. On the basis of the given series of 60 years long from 1948 to 2008, such parameters of diffusion processes as the mean (drift process) and variance (diffusion process) were calculated and their maps and time curves were constructed. The seasonal and long-term variability of calculated fields was studied as well as their dependencies on a discretization of the frequency intervals. These characteristics were analyzed and their geophysical interpretation was carried out. In particular, the known cycles of solar activity in 11 and 22 years were revealed. Numerical calculations were performed on the Lomonosov-2 supercomputer of the Lomonosov Moscow State University.

scholarly journals Applying an isotope-enabled regional climate model over the Greenland ice sheet: effect of spatial resolution on model bias

2021 ◽  
Vol 17 (4) ◽  
pp. 1685-1699
Author(s):  
Marcus Breil ◽  
Emanuel Christner ◽  
Alexandre Cauquoin ◽  
Martin Werner ◽  
Melanie Karremann ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
General Circulation ◽  
Climate Model ◽  
Regional Climate ◽  
Circulation Model ◽  
Ice Cores ◽  
Arctic Region ◽  
The Arctic ◽  
Simulation Results ◽  
The Arctic Region

Abstract. In order to investigate the impact of spatial resolution on the discrepancy between simulated δ18O and observed δ18O in Greenland ice cores, regional climate simulations are performed with the isotope-enabled regional climate model (RCM) COSMO_iso. For this purpose, isotope-enabled general circulation model (GCM) simulations with the ECHAM5-wiso general circulation model (GCM) under present-day conditions and the MPI-ESM-wiso GCM under mid-Holocene conditions are dynamically downscaled with COSMO_iso for the Arctic region. The capability of COSMO_iso to reproduce observed isotopic ratios in Greenland ice cores for these two periods is investigated by comparing the simulation results to measured δ18O ratios from snow pit samples, Global Network of Isotopes in Precipitation (GNIP) stations and ice cores. To our knowledge, this is the first time that a mid-Holocene isotope-enabled RCM simulation is performed for the Arctic region. Under present-day conditions, a dynamical downscaling of ECHAM5-wiso (1.1∘×1.1∘) with COSMO_iso to a spatial resolution of 50 km improves the agreement with the measured δ18O ratios for 14 of 19 observational data sets. A further increase in the spatial resolution to 7 km does not yield substantial improvements except for the coastal areas with its complex terrain. For the mid-Holocene, a fully coupled MPI-ESM-wiso time slice simulation is downscaled with COSMO_iso to a spatial resolution of 50 km. In the mid-Holocene, MPI-ESM-wiso already agrees well with observations in Greenland and a downscaling with COSMO_iso does not further improve the model–data agreement. Despite this lack of improvement in model biases, the study shows that in both periods, observed δ18O values at measurement sites constitute isotope ratios which are mainly within the subgrid-scale variability of the global ECHAM5-wiso and MPI-ESM-wiso simulation results. The correct δ18O ratios are consequently not resolved in the GCM simulation results and need to be extracted by a refinement with an RCM. In this context, the RCM simulations provide a spatial δ18O distribution by which the effects of local uncertainties can be taken into account in the comparison between point measurements and model outputs. Thus, an isotope-enabled GCM–RCM model chain with realistically implemented fractionating processes constitutes a useful supplement to reconstruct regional paleo-climate conditions during the mid-Holocene in Greenland. Such model chains might also be applied to reveal the full potential of GCMs in other regions and climate periods, in which large deviations relative to observed isotope ratios are simulated.

scholarly journals Insulation systems for structures on pile supports

2021 ◽  
Vol 263 ◽  
pp. 01010
Author(s):  
Vyacheslav Semenov ◽  
Igor Bessonov ◽  
Ekaterina Zinovieva ◽  
Elizaveta Mednikova
Keyword(s):  
Arctic Region ◽  
Mineral Wool ◽  
Climatic Conditions ◽  
Pile Foundations ◽  
The Arctic ◽  
Frozen Ground ◽  
Climatic Zones ◽  
Floor Structure ◽  
Insulation Systems ◽  
The Arctic Region

Construction on problem soils or in permafrost conditions involves using of pile foundations with a ventilated space under the floor structure. In this case, additional thermal insulation is required under the first-floor structure (above the ventilated space). The aim of research was to develop insulation systems for buildings on pile foundations for different climatic zones, including conditions of the arctic region and other regions with a predominance of ever-frozen ground. With the help of the THERM computer program, the conditions of bidimensional heat interchange in the enclosing structures of a building with pile foundation were simulated. The resulting models were analysed in terms of the thermophysical characteristics of the structures. As a result, the optimal version of the insulation system was chosen, effective both in the climatic conditions of the midland and in the especially cold conditions of Yakutia and Trans-Polar region (The Subarctic). This system included insulation with mineral wool slabs along the facade walls, with extruded foamed polystyrene along the basement part and the floor structure, and with rolled foamed polyethylene (with the formation of a seamless insulation shell) along the ventilated space under the floor structure and above, on top of insulation boards.

scholarly journals U.S. Arctic policy: the agenda of 2019

2020 ◽  
pp. 25-37
Author(s):  
Andrei Andreevich Kovalev
Keyword(s):  
United States ◽  
Arctic Region ◽  
The United States ◽  
Climatic Changes ◽  
The Arctic ◽  
Arctic Policy ◽  
Defense Cooperation ◽  
Relevant Consideration ◽  
The Arctic Region

This article explores the key stages of the development of U.S. policy with regards to Arctic Region. The goal is set to outline the fundamental interests of the United States in the Arctic, as well as analyze the actions aimed at their achievement. The article examines the main priorities in U.S. Arctic policy, namely the protection and preservation of resources and ecosystem in the Arctic Region, scientific study of climatic changes, peculiarities of economic development of Alaska, and national security interests of the state. The questions of interaction of Arctic states with regards to defense cooperation become increasingly relevant. Consideration of the mid-term and long-term prospects of U.S. Arctic policy allowed the author focusing attention on the news aspects of U.S. government actions. Maritime capabilities of the United States in the Arctic waters are views in the context of modern tendencies. The author attempted to trace the prospects for expansion of U.S. influence in the Arctic Region based on the current agenda of 2019.

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