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Concentrations and distribution of biogenic barium in surface sediments of Prydz Bay, Antarctica
Get PDFConcentrations of biogenic barium were investigated in surface sediments of Prydz Bay, Antarctica, during the 21st and 27th CHINARE cruises. Factors controlling the observed distribution are explored. Biogenic barium concentrations obtained from a sequential extraction procedure are compared with total concentrations obtained from the normative calculation based on a total digestion, and differences in the results are examined. Concentrations of biogenic barium, calculated by the normative calculation, were much higher than the concentrations obtained through sequential extraction; this discrepancy is the result of the occurrence of barium associated with Mn/Fe oxides, which represents an important component of total barium in these sediments. Concentrations of biogenic barium obtained from the sequential extraction range from 104 to 445 μg∙g-1, and the average concentration was 227 μg∙g-1. The highest concentrations of biogenic barium occur in the central area of the bay, where the seawater is more stable, while lower values occur in the bank and the ice shelf. Biogenic barium is significantly linearly correlated with biogenic barium and organic carbon, and similar in distribution of Chl a, which may indicate that primary productivity of phytoplankton in the surface water column is the main environmental factor regulating barium concentration and distribution
Analysis of recent climate change over the Arctic using ERA-Interim reanalysis data
Get PDFThis study investigates recent climate change over the Arctic and its link to the mid-latitudes using the ERA-Interim global atmospheric reanalysis data from the European Center for Medium-Range Weather Forecast (ECMWF). Since 1979, substantial surface warming, associated with the increase in anthropogenic greenhouse gases, has occurred over the Arctic. The greatest warming in winter has taken place offshore in the Kara-Barents Sea, and is associated with the increase in turbulent heat fluxes from the marginal ice zone. In contrast to the marked warming over the Arctic Ocean in winter, substantial cooling appears over Siberia and eastern Asia, linked to the reduction of Arctic sea ice during the freezing season (September–March). However, in summer, very little change is observed in surface air temperature over the Arctic because increased radiative heat melts the sea ice and the amount of turbulent heat gain from the ocean is relatively small. The heat stored in the upper ocean mixed layer in summer with the opening of the Arctic Ocean is released back to the atmosphere as turbulent heat fluxes during the autumn and through to the following spring. This warming of the Arctic and the reduced sea ice amplifies surface cooling over Siberia and eastern Asia in winter
Climate change among nomadic and settled Tungus of Siberia: continuity and changes in economic and ritual relationships with the natural environment
Get PDFLiving in close relationship with the Siberian environment, for several decades the Tungus (Evenk and
Even peoples) have been noticing numerous changes in climate, flora and fauna. Based on fieldwork among reindeer herders, hunters and fishermen in Yakutia, the Amur region and Kamchatka, this paper explores how climate change is perceived, and how it causes economic, social and ritual changes. It questions the modifications of the economic and religious human-environment relationships through various aspects. It analyses the indigenous perception of a link
between the environment and identity and the indigenous notion of adaptation and vulnerability. It also compares their adaptive strategies that either use old techniques, or trigger mutations. In this context, the notion of reciprocity seems to be disappearing and a new notion of time-space in managing the environment is appearing. This paper analyses the religious changes, such as the creation of new rituals and millenarian narratives or the rebirth of shamanistic legends
Assessing Doppler velocities of Rankin Inlet F-region echoes
Get PDFDoppler velocities observed by the Rankin Inlet (RKN) PolarDARN radar are assessed with a focus on data in the beams oriented roughly along the magnetic meridian. Hourly scatter plots for every month are built. They are shown to vary widely, with median values showing very clear magnetic local time variation with maximum magnitude during pre-noon and pre-midnight hours. The histograms contain a significant amount of very small velocity data that dominates at farther ranges and during the daytime. Near noon data show generally antisunward flows but at large ranges/magnetic latitudes and very close to noon, sunward flows occur for periods of positive IMF Bz. The reverse flows are stronger during spring equinox. The velocity magnitude was found to depend linearly on the IMF Bz and interplanetary electric field. Velocities are often found to be smaller than those expected from the statistical convection model of Ruohoniemi and Greenwald –1996
Optical and SuperDARN radar observations of duskside shock aurora over Zhongshan Station
Get PDFWe present observations of a duskside shock aurora occurred on 21 April 2001 by the SuperDARN radar at Syowa Station and the all-sky camera at Zhongshan Station (ZHS) in Antarctica when the radar was operated in fast-scan mode covering the ZHS region. With the two independent data sets, we examine ionospheric plasma convection and aurora arising from a sudden impulse (SI) event associated with an interplanetary shock. During the transient shock compression, the aurora was quiescent without any optical emission at the preliminary impulse of the SI. About 7 min later, a new thin auroral arc with brighter emissions and a lifetime of ~14 min expanded westward from the region above ZHS during the main impulse of the SI. SuperDARN radar line-of-sight measurements showed periodical oscillation in the flow direction with ultra-low-frequency waves having a period of ~8 min during the shock compression. We suggest that downward field-aligned current during the preliminary impulse stage of the SI was the main driver of the first plasma flow reversal, and the subsequent new discrete auroral arc may be associated with field-aligned acceleration in the region of the main impulse related upward field-aligned currents. The ground magnetometer observations suggest that the oscillation of the ionospheric convection on the duskside was associated with field line resonance activity
Diversity and bioactivity of actinomycetes from Signy Island terrestrial soils, maritime Antarctic
Get PDFThe Antarctic represents a largely untapped source for isolation of new microorganisms with potential to produce bioactive natural products. Actinomycetes are of special interest among such microorganisms as they are known to produce a large number of natural products, many of which have clinical, pharmaceutical or agricultural applications. We isolated, characterized and classified actinomycetes from soil samples collected from different locations on Signy Island, South Orkney Islands, in the maritime Antarctic. A total of 95 putative actinomycete strains were isolated from eight soil samples using eight types of selective isolation media. The strains were dereplicated into 16 groups based on morphology and Amplified Ribosomal DNA Restriction Analysis (ARDRA) patterns. Analysis of 16S rRNA gene sequences of representatives from each group showed that streptomycetes were the dominant actinomycetes isolated from these soils; however, there were also several strains belonging to diverse and rare genera in the class Actinobacteria, including Demetria, Glaciibacter, Kocuria, Marmoricola, Nakamurella and Tsukamurella. In addition, screening for antibacterial activity and non-ribosomal peptide synthetase genes showed that many of the actinomycete strains have the potential to produce antibacterial compounds
The Little Book on Permafrost
Get PDFThis e-learning material was created within the “PAGE21 – Permafrost in the Arctic and its Global Effects in the 21st Century“ project. The project is an EU Seventh Framework Programme funded large scale integrating collaborative project, aiming to understand the interactions between the global climate system and the frozen ground.
The multidisciplinary nature of the science and the wide range of countries covered in the PAGE21 project combine to provide a wealth of opportunities for disseminating information.
One of the tasks within the project was to create materials for education and training and that way ensure that the vast amount of knowledge entailed in the project consortium will be distributed to the widest possible audience for the
benefit of community as a whole.
This e-learning material “Little book on Permafrost” was created by the PAGE21 participant Arctic Portal in Iceland with the support of the PAGE21 project office as well as the project coordination team at Alfred Wegener Institute, Potsdam,
Germany
The role of the Arctic and Antarctic and their impact on global climate change: Further findings since the release of IPCC AR4, 2007
Get PDFChanges in the climate of the Arctic and of the Antarctic have been of great concern to the international scientific and social communities since the release in 2007 of the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4). Since then, many new findings have been reported from observations and research carried out in the Arctic and Antarctic during the fourth International Polar Year (IPY). There is evidence that global warming is inducing rapid changes in the Arctic and Antarctic, in both a quantitative and qualitative sense, and that these regional changes could be used as indicators of global climate change. Declining Arctic sea ice could affect winter snowfall across much of the Northern Hemisphere by bringing harsher winters. Projections suggest that summertime Arctic sea ice will disappear by 2037. By the 2070s, the Antarctic ozone hole will recover to the level of the early 1980s, following the ban on the production of Freon earlier this century. With the loss of the shielding effect of the ozone hole, Antarctic surface temperatures will increase, ice sheets in East Antarctica will begin to melt, and the Antarctic sea ice will retreat. Therefore, sea level rise will become an increasingly serious issue this century. As sea surface temperature rises, the Southern Ocean will become less effective as a sink for atmospheric CO2 and the increase of surface CO2 will be faster than that in the atmosphere. Increased surface CO2 would lead to ocean acidification and affect ecological systems and food chains
Spatial variability of soil nutrients in Punta Fort William, Greenwich Island, maritime Antarctic
Get PDFThis study aims to report baseline soil nutrients, specifically the organic carbon, nitrogen and phosphorus profile, in soil samples collected from Punta Fort William on Greenwich Island in maritime Antarctic. Samples were collected along two transect lines during the early summer of 2008. Ward’s method of hierarchical agglomerative clustering was employed to group the sampling points based on their physico-chemical properties. In this context, the soil samples can be grouped into three major clusters: (1) Samples with intensive biological activities, (2) samples from the area recently exposed by glacial retreat and (3) samples from barren and dried areas. Nutrient contents in Punta Fort William are driven by the intensity of biological activities as well as melt water from the Quito glacier
The United Nations Declaration on the Rights of Indigenous Peoples: A Manual for National Human Rights Institutions
Get PDFThis Manual aims to support and strengthen the work of national human rights institutions (NHRIs) – whether they are human rights commissions or ombudsman offices – in the promotion, protection and enjoyment of the rights of indigenous peoples, especially NHRIs that are established in accordance with the Paris Principles.
It is designed to assist these institutions learn about the United Nations Declaration on the Rights of Indigenous Peoples (the Declaration) by providing a broad understanding of the legal nature of the rights it contains, as well as the relevant obligations of States, in order to ensure that indigenous peoples’ rights are fully realized.
We hope that the information provided will also be useful to indigenous community leaders and other stakeholders on how to make use of the NHRIs that operate in the countries in which they live