Search Results (6)

The Skaftafellsjökull is an outlet glacier in southern Iceland that has been retreating since 1890. While multiple studies have examined primary succession on the foreland of this glacier, no study has examined the distribution of woody biomass on the outwash plain. We investigated the distribution of one species, Betula pubescens, that grows on the foreland moraines and outwash plain of this glacier. The topography of the outwash plain is heterogeneous, consisting of broad bars of outwash gravel and boulders that are separated by narrow incised channels and broader swales. Vegetation on the outwash plain is primarily a moss–heath community. Birch are sparse on the outwash bar tops, but are more abundant and larger in the channels and swales between the bars. Although the area of the channels on the outwash plain is much less than that of the bar surfaces, the woody biomass of the outwash plain is dominated by the birch within these channels. Consequently, the mean woody biomass of the outwash plain exceeds that of the moraines. We propose that the microhabitat of the outwash plain channels provides a favorable environment for the growth of birch, primarily by providing a fine-grained substrate that promotes successful seeding and growth. Full article

One of the more visible consequences of anthropogenic climate change is the ongoing retreat of glaciers worldwide. Rates of primary succession in the resulting glacial forelands are commonly calculated from a single measurement set using a single set of measurements across a landscape of varying age, but repeated measurements over decadal scales may be a more effective means of examining the rates and trends of colonization and community development. Repeated measurements of vegetation groups in a glacial foreland in southern Iceland demonstrate that successional changes are measurable, as shown by the calculation of the dissimilarity index at sites over a 15 year interval. Inter-site dissimilarity validates the essential paradigm of primary succession, where vegetative coverage increases in the glacial foreland as a function of time and supports earlier interpretations saying that species richness decreases on older surfaces, even as the total vegetation cover increases. However, successional processes are subject to major abiotic factors, such as aspect, which is controlled by landscape topography, and the substrate composition. The glacial moraines and outwash plain are underlain by different substrates which produce separate successional trajectories. Succession on the moraines ultimately produces a birch-shrub-heath community, while the outwash deposits promote development of a moss-heath community. Full article

The lichen Cetraria islandica (L.) Ach. has been used in traditional and modern medicines for its many biological properties such as immunological, immunomodulating, antioxidant, antimicrobial, and anti-inflammatory activities. This species is gaining popularity in the market, with interest from many industries for selling as medicines, dietary supplements, and daily herbal drinks. This study profiled the morpho-anatomical features by light, fluorescence, and scanning electron microscopy; conducted an elemental analysis using energy-dispersive X-ray spectroscopy; and phytochemical analysis was performed using high-resolution mass spectrometry combined with a liquid chromatography system (LC-DAD-QToF) of C. islandica. In total, 37 compounds were identified and characterized based on comparisons with the literature data, retention times, and their mass fragmentation mechanism/s. The identified compounds were classified under five different classes, i.e., depsidones, depsides, dibenzofurans, aliphatic acids, and others that contain simple organic acids in majority. Two major compounds (fumaroprotocetraric acid and cetraric acid) were identified in the aqueous ethanolic and ethanolic extracts of C. islandica lichen. This detailed morpho-anatomical, EDS spectroscopy, and the developed LC-DAD-QToF approach for C. islandica will be important for correct species identification and can serve as a useful tool for taxonomical validation and chemical characterization. Additionally, chemical study of the extract of C. islandica led to isolation and structural elucidation of nine compounds, namely cetraric acid (1), 9′-(O-methyl)protocetraric acid (2), usnic acid (3), ergosterol peroxide (4), oleic acid (5), palmitic acid (6), stearic acid (7), sucrose (8), and arabinitol (9). Full article

Here we report, for the first time, the occurrence of the bacteria from the species complex Pseudomonas syringae in Iceland. We isolated this bacterium from 35 of the 38 samples of angiosperms, moss, ferns and leaf litter collected across the island from five habitat categories (boreal heath, forest, subalpine and glacial scrub, grazed pasture, lava field). The culturable populations of P. syringae on these plants varied in size across 6 orders of magnitude, were as dense as 10⁷ cfu g⁻¹ and were composed of strains in phylogroups 1, 2, 4, 6, 7, 10 and 13. P. syringae densities were significantly greatest on monocots compared to those on dicots and mosses and were about two orders of magnitude greater in grazed pastures compared to all other habitats. The phylogenetic diversity of 609 strains of P. syringae from Iceland was compared to that of 933 reference strains of P. syringae from crops and environmental reservoirs collected from 27 other countries based on a 343 bp sequence of the citrate synthase (cts) housekeeping gene. Whereas there were examples of identical cts sequences across multiple countries and continents among the reference strains indicating mixing among these countries and continents, the Icelandic strains grouped into monophyletic lineages that were unique compared to all of the reference strains. Based on estimates of the time of divergence of the Icelandic genetic lineages of P. syringae, the geological, botanical and land use history of Iceland, and atmospheric circulation patterns, we propose scenarios whereby it would be feasible for P. syringae to have evolved outside the reach of processes that tend to mix this bacterial complex across the planet elsewhere. Full article

Although the common cold, usually caused by human rhinoviruses, is responsible for enormous damage to the economy and health every year, there are hardly any treatment options or prophylaxis for rhinovirus infections. In this work, the potential of a hydrogel complex, based on polymers and an aqueous extract of Icelandic moss in isla^® medic lozenges (Engelhard Arzneimittel, Niederdorfelden, Germany), and two other hydrogels (based on solely xanthan gum or sodium hyaluronate) are investigated for the first time in order to prevent and treat rhinovirus infections. By means of rheological investigations, we demonstrate that isla^® medic and containing polymers cause artificial saliva to thicken. Additionally, we demonstrate that the thickening results in the formation of a physical diffusion barrier, which leads to a significant reduction in plaques in a preventive plaque assay with rhinovirus 14 (RV-14). Furthermore, it is shown in a curative plaque assay that the hydrogel complex also has a curative effect on rhinovirus infections in that it reduces the spread of the RV-14-infection on H1-HeLa cell monolayers. Overall, polymer-based hydrogels and related products, such as isla^® medic, could contribute to the prevention and treatment of rhinovirus infections. Full article

With growing tourism in natural areas, monitoring recreational impacts is becoming increasingly important. This paper aims to evaluate how different trampling intensities affect some common Icelandic plant communities by using digital photographs to analyze and quantify vegetation in experimental plots and to monitor vegetation recovery rates over a consecutive three-year period. Additionally, it seeks to evaluate the use of image analysis for monitoring recreational impact in natural areas. Experimental trampling was conducted in two different sites representing the lowlands and the highlands in 2014, and the experimental plots were revisited in 2015, 2016, and 2017. The results show that moss has the highest sensitivity to trampling, and furthermore has a slow recovery rate. Moss-heaths in the highlands also show higher sensitivity and slower recovery rates than moss-heaths in the lowlands, and grasslands show the highest resistance to trampling. Both methods tested, i.e., Green Chromatic Coordinate (GCC) and Maximum Likelihood Classification (MLC), showed significant correlation with the trampling impact. Using image analysis to quantify the status and define limits of use will likely be a valuable and vital element in managing recreational areas. Unmanned aerial vehicles (UAVs) will add a robust way to collect photographic data that can be processed into vegetation parameters to monitor recreational impacts in natural areas. Full article