Biological Soil Crust Microalgae and Cyanobacteria - Key Players in Polar and Alpine Ecosystems

The Polar Regions and alpine zones are extremely hostile environments due to prevailing low temperatures, high levels of solar radiation and extreme seasonality. Water is almost exclusively present as ice and snow, thus, unavailable for organisms. These conditions restrict the vegetational cover to be sparse or completely absent. However, the soil surface is not barren but mostly covered by biological soil crusts (BSCs). These crusts are complex aggregations of different organisms, such as Cyanobacteria and other prokaryotes, eukaryotic microalgae, bryophytes, Fungi, lichens and a versatile microfauna, occurring in varying portions. Biocrusts are integral parts of cold ecosystems as they contribute extensively to primary production and nitrogen fixation. Furthermore, BSCs are important ecosystem engineers that prevent soil loss, change hydrological patterns, albedo, and increase soil fertility. Global change is a major threat to these communities as it leads to alterations in biodiversity amplified by an invasion of non-indigenous species. Hence, studying and monitoring BSCs is essential to recognize shifts in community structures early on and predict future scenarios. Reliable methodologies are the basis for sound results and conclusions. Extracting nucleic acids from BSC samples successfully is highly dependent on, for instance, soil properties. Soil often contains high amounts of humics, which can interfere with enzymatic reactions and should be removed. In this thesis, it was found that an extraction method based on a cetyl trimethylammonium bromide performed superior to commercial kits. All BSC isolates processed with this protocol yielded high-quality nucleic acids. Thus, this procedure and variations of it were used in the course of this project. Biodiversity assessment is crucial to unravel the complexity of communities such as biocrusts. However, cultivating and examining individual organisms has several limitations and will only reveal a small fraction of the actual biodiversity. Molecular methods may overcome these limitations to a certain degree as total DNA or RNA is extracted from the sample and analyzed. In this thesis, five different BSCs were studied, four from Svalbard, Norway, in the Arctic and one from Livingston Island, a part of the Antarctic Peninsula. All five BSCs were in a late successional stage with bryophytes being most dominant. Moreover, Cyanobacteria exhibited a high relative abundance, while microalgae appeared to be diverse but only present at a low relative abundance. The genera Chloromonas (Chlorophyceae), Coccomyxa, Dictyochlorop- sis, Elliptochloris, Leptosira (Trebouxiophyceae), Spumella (Chrysophyceae) and Nostoc (Cyanobacteria) were detected in all samples suggesting an ubiquitous distribution. Especially, Nostoc may be an important keystone species in Polar Regions which may be further investigated in future studies. Furthermore, the presence of sulfur Bacteria indicates that BSCs are involved in sulfur cycling. Overall, the combination of cultivation based and molecular approaches provides a more comprehensive picture of BSC communities. As mentioned above, BSC organisms have to cope with extreme conditions such as water scarcity, which can cause desiccation. The ability to tolerate water deprivation and adapt to it was studied in an alpine strain of Zygnema circumcarinatum (Zygnematophyceae). Similar to land plants, Zygnema increases the transcript pool of early light-induced proteins, aquaporins, reactive oxygen species scavengers and chaperones such as late embryogenesis abundant proteins. Additionally, transcriptional changes in the carbohydrate and lipid metabolism suggest accumulation of sucrose and membrane modifications, respectively. In conclusion, the integration of physiological, cell-biological and omic approaches is a promising way to get extensive insights into the biodiversity and ecology of biological soil crusts. The outcome can be merged to shed light on present community patterns and functionality, and help to generate predictions models for future developments

‘Detachment’ of icefield outlet glaciers – catastrophic thinning and retreat of the Columbia Glacier (Canada)

We present an investigation of changes taking place on the Columbia Glacier – a lake-terminating outlet of the Columbia Icefield in the Canadian Rockies. The Columbia Icefield is the largest, and one of the most important, ice bodies in the Canadian Rockies. Like other ice masses, it stores water as snow and ice during the winter and releases it during warmer summer months, sustaining river flows and the ecosystems that rely on them. However, the Columbia Glacier and Icefield is shrinking. We use Landsat and Sentinel-2 imagery to show that the Columbia Glacier has retreated increasingly rapidly in recent years, and suggest that this looks set to continue. Importantly, we identify a previously undocumented process that appears to be playing an important role in the retreat of this glacier. This process involves the ‘detachment’ of the glacier tongue from its accumulation area in the Columbia Icefield. This process is important because the tongue is cut off from the accumulation area and there is no replenishment of ice that melts in the glacier's ablation area by flow from upglacier. As a consequence, for a given rate of ablation, the ice in the tongue will disappear much faster than it would if the local mass loss by melting/calving was partly offset by mass input by glacier flow. Such a change would alter the relationship between rates of surface melting and rates of glacier frontal retreat. We provide evidence that detachment has already occurred elsewhere on the Columbia Icefield and that it is likely to affect other outlet glaciers in the future. Modelling studies forecast this detachment activity, which ultimately results in a smaller ‘perched’ icefield without active outlets

Inland extent of the Weddell Sea Rift imaged by new aerogeophysical data

Peer reviewedPostprin

Childhood overweight and obesity abatement policies in Europe

Over the past two decades, a concerted effort to combat the rising tide of childhood overweight and obesity has taken shape. The World Health Organization (WHO) Commission on Ending Childhood Obesity (ECHO) provides recommendations for six priority areas of action, including the promotion of healthy food consumption, promotion of physical activity, preconception and pregnancy care, early childhood diet and physical activity, healthy nutrition and physical activity for school-aged children, and community-based weight management. This paper provides a snapshot of policies and measures aligned to these areas of action within the WHO European Region in order to encourage other countries to make similar efforts. Examples are drawn from Portugal (sugar-sweetened beverage tax, integrated nutrition strategy), the United Kingdom (soft drink levy, active commuting programs, urban design principles), Lithuania (prohibition of energy drinks), Norway (industry and government partnerships to promote healthier foods, nutrition education curriculum for schools), Hungary (tax subsidies to promote healthy diets), the European Union (cross-border marketing regulations, preconception and pregnancy care), Slovenia (food marketing restrictions), Spain (marketing restrictions within educational settings), Poland (investing in sports infrastructure), Russia (increasing sports participation), Estonia (redevelopment of the physical education curriculum), Netherlands (preconception and pregnancy care), Croatia (conditions to support breastfeeding), Austria (perinatal and early childhood nutrition), Czechia (life-course strategy), San Marino (nutrition and physical activity for school-aged children), Ukraine (potable water for schools), Ireland and Italy (community-based weight management approaches). Our findings suggest that a large disparity exists among the type and breadth of policies adopted by Member States, with a mix of single-issue policy responses and more cohesive strategies. The role of data, implementation research, and ongoing surveillance of country-level progress related to childhood overweight and obesity policies are discussed as an essential part of the iterative process of policy development. Additional work to systematically gather context-specific information on policy development, implementation, and reach according to ECHO's six areas of action by WHO European Region countries will inform future policy paradigms within the region.The authors gratefully acknowledge support through a grant from the Russian government in the context of the WHO European Office for the Prevention and Control of NCDs. Acesso de acordo com página web do editor da revista.info:eu-repo/semantics/publishedVersio

Subglacial controls on the flow of Institute Ice Stream, West Antarctica

The Institute Ice Stream (IIS) rests on a reverse-sloping bed, extending >150 km upstream into the ~1.8 km deep Robin Subglacial Basin, placing it at the threshold of marine ice-sheet instability. Understanding IIS vulnerability has focused on the effect of grounding-line melting, which is forecast to increase significantly this century. Changes to ice-flow dynamics are also important to IIS stability, yet little is known about them. Here we reveal the trunk of the IIS occurs downstream of the intersection of three discrete subglacial features; a large ‘active’ subglacial lake, a newly-discovered sharp transition to a zone of weak basal sediments, and a major tectonic rift. The border of IIS trunk flow is confined by the sediment on one side, and by a transition between basal melting and freezing at the border with the Bungenstock Ice Rise. By showing how basal sediment and water dictate present-day flow of IIS, we reveal that ice-sheet stability here is dependent on this unusual arrangement

A temperate former West Antarctic ice sheet suggested by an extensive zone of bed channels

Several recent studies predict that the West Antarctic Ice Sheet will become increasingly unstable under warmer conditions. Insights on such change can be assisted through investigations of the subglacial landscape, which contains imprints of former ice-sheet behavior. Here, we present radio-echo sounding data and satellite imagery revealing a series of ancient large sub-parallel subglacial bed channels preserved in the region between the Möller and Foundation Ice Streams, West Antarctica. We suggest that these newly recognized channels were formed by significant meltwater routed along the icesheet bed. The volume of water required is likely substantial and can most easily be explained by water generated at the ice surface. The Greenland Ice Sheet today exemplifies how significant seasonal surface melt can be transferred to the bed via englacial routing. For West Antarctica, the Pliocene (2.6–5.3 Ma) represents the most recent sustained period when temperatures could have been high enough to generate surface melt comparable to that of present-day Greenland. We propose, therefore, that a temperate ice sheet covered this location during Pliocene warm periods

Inequalities in education and national income are associated with poorer diet: pooled analysis of individual participant data across 12 European countries

Background: Malnutrition linked to noncommunicable diseases presents major health problems across Europe. The World Health Organisation encourages countries to conduct national dietary surveys to obtain data to inform public health policies designed to prevent noncommunicable diseases. Methods: Data on 27334 participants aged 19-64y were harmonised and pooled across national dietary survey datasets from 12 countries across the WHO European Region. Weighted mean nutrient intakes were age-standardised using the Eurostat 2013 European Standard Population. Associations between country-level Gross Domestic Product (GDP) and key nutrients and nutrient densities were investigated using linear regression. The potential mitigating influence of participant-level educational status was explored. Findings: Higher GDP was positively associated with total sugar intake (5·0% energy for each 10% increase in GDP, 95% CI 0·6, 9·3). Scandinavian countries had the highest vitamin D intakes. Participants with higher educational status had better nutritional intakes, particularly within lower GDP countries. A 10% higher GDP was associated with lower total fat intakes (-0·2% energy, 95% CI -0·3, -0·1) and higher daily total folate intakes (14µg, 95% CI 12, 16) in higher educated individuals. Interpretation: Lower income countries and lower education groups had poorer diet, particularly for micronutrients. We demonstrate for the first time that higher educational status appeared to have a mitigating effect on poorer diet in lower income countries. It illustrates the feasibility and value of harmonising national dietary survey data to inform European policy regarding access to healthy diets, particularly in disadvantaged groups. It specifically highlights the need for strong policies supporting nutritional intakes, prioritising lower education groups and lower income countries

Radar-derived bed roughness characterization of Institute and Möller ice streams, West Antarctica, and comparison with Siple Coast ice streams

Subglacial bed conditions exert a significant control on ice stream behavior and evolution, and can be characterized by determining bed roughness from FFT analysis of radar-imaged basal reflectors. Here we assess bed roughness across Institute and Moller ice streams, West Antarctica, and compare our findings with bed roughness determined across the Siple Coast ice streams. We find that variations in bed roughness are spatially organized, and attribute this to the varying efficacy of subglacial erosion and deposition, with rougher (inland, slow-flowing) regions largely manifesting preglacial topography, and smoother (downstream, fast-flowing) regions evincing significant postglacial modification to the subglacial landscape. The observed similarities between bed roughness characteristics of IIS/MIS and the Siple ice streams suggest that IIS and MIS are largely underlain by wet, poorly consolidated sediments, and may therefore be vulnerable to the types of dynamical instabilities experienced by the Siple ice streams