Icelandic Soils Research Articles

Low nitrous oxide fluxes from mineral affected peatland soils in Iceland

Nitrous oxide (N2O) is a potent greenhouse gas, and soil is one of its most substantial sources. Emissions are influenced by both biotic and abiotic processes, as well as the physiochemical properties of the medium. Organic soils fully drained in boreal climates are a potentially significant source of nitrous oxide. Lower, drainage levels and nutrient availability have been shown to reduce N2O emissions. Predicting N2O emissions from agriculturally managed peatlands is challenging. In situ measurements are crucial for addressing these difficulties. This study presents three years of in situ field measurements of nitrous oxide fluxes and soil hydrological status in peatland soils under different agricultural management regimes: cultivated drained (CD), uncultivated drained (UCD), and wet (W) in Western Iceland. Fluxes were quantified by analysing a time-concentration series obtained from permanent chambers and subsequently evaluated using gas chromatography in the laboratory. The minimum potential N2O consumption rate (mean ± 95 % Cl) was estimated as 0.76 ± 0.38, 0.56 ± 0.18 and 0.56 ± 0.14 mg N2O-N m⁻² day⁻¹ for CD, UCD, and W sites, respectively. Yearly accumulated emissions were estimated as 2.24 ± 1.47, 1.26 ± 0.64 and 0.26 ± 0.44 kg N2O-N ha−1 yr−1 for CD, UCD, and W sites, respectively. The relatively low emission rates observed at drained sites can be explained by the stable water content, and by limited availability of soil phosphorus, which hampers N2O production and potentially leads to more active N2O consumption. Both the stable water content and low phosphorus availability is explained by mineral inputs to the peatlands, acting through decreased soil unsaturated hydraulic conductivity and increased phosphorus retention. The effects of mineral content offer potential mitigation option to decrease N2O emissions. This study highlights the complexity of N2O emissions from peatland soils and emphasizes the significance of site-specific factors in managing greenhouse gas emissions. Further studies investigating the underlying processes behind N2O fluxes in the peatland and andic soils are recommended.

Penicillium poederi and P. tirolense, two new species of section Torulomyces.

Here we describe two new species of the genus Penicillium section Torulomyces with solitary phialides. Penicillium poederi sp. nov. was isolated from volcanic soils in Iceland. Penicillium tirolense sp. nov. was isolated from a sporocarp of Serpula lacrymans. Both species are characterised by slow growth rates and the production of a brown soluble pigment on CYA, conidiophores with solitary ampulliform phialides with smooth-walled stipes and warty, globose conidia and with connectives without visible rings. The spores of. P. poederi are 2.5 μm diam, while the spores of P. tirolense are 2.0 μm diam. In a multigene phylogeny based on the ITS, BenA, CaM and RPB2 gene regions P. tubakianum and P. wollemiicola are the closest relatives of P. poederi. This species differs from P. tubakianum and P. wollemiicola by its growth rates and by its pigmentation. The holotype of P. poederi is IB2017/0007, while SF014017 (CBS 147622) is a culture derived from the holotype. The closest relatives of P. tirolense are P. austricola and P. riverlandense. It differs from P. austricola by lower growth rates on all tested media and temperatures and by its larger spores. It differs from P. riverlandense by lower growth rates and the absence of growth at 37 °C. The holotype of P. tirolense is IBF2019/0162, while SF015108 (CBS 147625) is a culture derived from the holotype. Citation: Kirchmair M, Embacher J, Heimdörfer D, Walch G, Neuhauser S (2022). Penicillium poederi and Penicillium tirolense, two new species of section Torulomyces. Fungal Systematics and Evolution 10: 91-101. doi: 10.3114/fuse.2022.10.03.

Iron speciation changes and mobilization of colloids during redox cycling in Fe-rich, Icelandic peat soils

Soils of Iceland are characterized by an abundance of short-range order (SRO) iron (Fe) minerals and aluminosilicates. Interactions between these SRO mineral phases and soil organic carbon (OC) promote long-term stabilization of the latter through the formation of mineral-organic complexes and aggregates. However, Icelandic soils are also exposed to high rainfall events, which induce anoxic conditions, facilitate microbial reduction of ferric Fe, and may lead to the mobilization of mineral-associated OC. Here, we explored the fate of OC during Fe redox cycling by incubating six organic-rich soil horizons from three typical soil types across Iceland (Histosols, Histic and Gleyic Andosols) as soil slurries under anoxic conditions for up to 5 weeks and followed the effects of re-oxidation after 1, 2, and 5 weeks. Changes in solid-phase Fe speciation were assessed by combining Fe K-edge X-ray absorption spectroscopy with time-resolved parallel selective chemical extractions, and trends in aqueous element contents were measured in both the dissolved (<3 kDa) and fine colloidal fractions (3 kDa to 0.45 µm). In all soils, anoxic incubation resulted in microbial reduction of Fe(III) and concomitant increases in soil solution pH. However, soils containing SRO Fe minerals underwent more extensive Fe reduction. Rapid (<1 wk) increases in aqueous element contents (including Fe, Al, and OC) were recorded in all soil slurries, and mobilization of colloids occurred in soil horizons which reached the highest pH values (>4.6). Mobilized colloids persisted during re-oxidation of the soil slurries, which also resulted in the formation of new Fe mineral phases, the composition of which was influenced by initial soil Fe mineralogy. Collectively, our results suggest that increases in the frequency of redox cycles in Icelandic soils are likely to result in shifts in Fe mineralogy and may contribute to the increased mobilization of soil OC as organic-Fe-/Al-colloids.

Changes in Icelandic soil microbiomes from the forefield of retreating glaciers revealed by Illumina and MinION sequencing

Climate change is affecting the sub‐Arctic landscape more than mid‐latitude locations on Earth. This is especially evident in Iceland where glaciers are now receding at a rapid pace. As glaciers retreat, newly exposed land undergoes primary succession. The soil microbiome is a critical component of succession; microbial communities often act as first colonizers and are key players in soil neogenesis. Warming‐related changes in the composition of soil microbes may increase the amount of gasses such as methane and CO2 produced by soil bacteria, as well as expose potentially new pathogens. Therefore, it is important to collect long‐term data sets from diverse locations throughout the Arctic and sub‐Arctic to form a clearer picture of how climate change affects these areas. We are developing a chronosequence of soil microbiome data and extent mapping at two outlet glaciers on the South coast of Iceland (Sólheimajökull and Kvíárjökull). During our work, we have optimized a field‐based soil extraction protocol for remote DNA extraction. We compare microbiome communities between multiple sampling locations to understand how the organismal composition changes as the land recovers. We hypothesize that microbial populations will change in composition as we move farther away from the glacier’s margin. We also compare Illumina and MinION sequencing results on the same samples. We expect that MinION sequencing will be able to produce species‐level identification but may produce a different yet overlapping population set when compared with Illumina sequencing data. In addition to population‐level changes (such as nitrogen pathway development) we are searching the data to identify antibiotic resistances. The data gathered in this first‐pass analysis expands our current knowledge of soil microbiomes in the sub‐Arctic and provides a foundation for a long‐term study of the region.

Genetic Diversity and Dispersal of Aspergillus fumigatus in Arctic Soils.

Aspergillus fumigatus is a saprophytic mold and an opportunistic pathogen with a broad geographic and ecological distribution. A. fumigatus is the most common etiological agent of aspergillosis, affecting over 8,000,000 individuals worldwide. Due to the rising number of infections and increasing reports of resistance to antifungal therapy, there is an urgent need to understand A. fumigatus populations from local to global levels. However, many geographic locations and ecological niches remain understudied, including soil environments from arctic regions. In this study, we isolated 32 and 52 A. fumigatus strains from soils in Iceland and the Northwest Territories of Canada (NWT), respectively. These isolates were genotyped at nine microsatellite loci and the genotypes were compared with each other and with those in other parts of the world. Though significantly differentiated from each other, our analyses revealed that A. fumigatus populations from Iceland and NWT contained evidence for both clonal and sexual reproductions, and shared many alleles with each other and with those collected from across Europe, Asia, and the Americas. Interestingly, we found one triazole-resistant strain containing the TR34 /L98H mutation in the cyp51A gene from NWT. This strain is closely related to a triazole-resistant genotype broadly distributed in India. Together, our results suggest that the northern soil populations of A. fumigatus are significantly influenced by those from other geographic regions.

Microbial Diversity in Subarctic Biocrusts from West Iceland following an Elevation Gradient.

Biological soil crusts (biocrusts) are essential communities of organisms in the Icelandic soil ecosystem, as they prevent erosion and cryoturbation and provide nutrients to vascular plants. However, biocrust microbial composition in Iceland remains understudied. To address this gap in knowledge, we applied high-throughput sequencing to study microbial community composition in biocrusts collected along an elevation gradient (11–157 m a.s.l.) stretching away perpendicular to the marine coast. Four groups of organisms were targeted: bacteria and cyanobacteria (16S rRNA gene), fungi (transcribed spacer region), and other eukaryotes (18S rRNA gene). The amplicon sequencing of the 16S rRNA gene revealed the dominance of Proteobacteria, Bacteroidetes, and Actinobacteria. Within the cyanobacteria, filamentous forms from the orders Synechococcales and Oscillatoriales prevailed. Furthermore, fungi in the biocrusts were dominated by Ascomycota, while the majority of reads obtained from sequencing of the 18S rRNA gene belonged to Archaeplastida. In addition, microbial photoautotrophs isolated from the biocrusts were assigned to the cyanobacterial genera Phormidesmis, Microcoleus, Wilmottia, and Oscillatoria and to two microalgal phyla Chlorophyta and Charophyta. In general, the taxonomic diversity of microorganisms in the biocrusts increased following the elevation gradient and community composition differed among the sites, suggesting that microclimatic and soil parameters might shape biocrust microbiota.

The lithium isotope response to the variable weathering of soils in Iceland

This study has analysed Li isotopes ratios from well-studied soil and pore water profiles from Iceland that have the same parent material but have experienced different degrees of chemical weathering. Thus, from least to most weathered, we have analysed vitrosols (V), gleyic andosols (GA), brown andosols (BA), Histosols (H) and Histic Andosols (HA). Although the most weathered H and HA soils have the highest content in clay-sized material, they have the least fractionated δ7Lipore water values. In contrast, the least weathered GA and BA pore waters are most fractionated for Li isotopes. Given that Li isotope ratios are fractionated by clay mineral formation, this appears counter-intuitive. A single trend for all samples of δ7Li as a function of Li/Na ratios suggests that they are all controlled by a process with a single fractionation factor, in this case likely the formation of poorly-crystalline allophane, which dominates in the “least weathered” soils. This rapidly forming secondary mineral dominates Li isotope fractionation over more slowly-forming crystalline clays. The fractionation along a single path shows that the key process here in controlling the Li isotope ratio of surface waters is the degree of Li uptake by secondary minerals. This does not necessarily correspond to the amount of clay minerals present in the soil, but to the amount of clay minerals that are being newly formed in a single passage of the pore water through the soil, or are in equilibrium with soil solutions at the time of sampling.

Potential Source Contribution Function Analysis of High Latitude Dust Sources over the Arctic: Preliminary Results and Prospects

The results of a preliminary investigation of the dust sources in the Arctic based on their geochemical properties by potential source contribution function (PSCF) analysis are presented in this paper. For this purpose, we considered one year of aerosol geochemical data from Ny-Ålesund, Svalbard, and a short list of chemical elements (i.e., Al, Fe, Mn, Ti, Cr, V, Ni, Cu, and Zn) variably related to the dust fraction. Based on PSCF analysis: (i) four different dust source areas (i.e., Eurasia, Greenland, Arctic-Alaska, and Iceland) were characterized by distinguishing geochemical ranges and seasonal occurrence; and (ii) a series of typical dust days from the distinct source areas were identified based on the corresponding back trajectory patterns. Icelandic dust samples revealed peculiar but very variable characteristics in relation to their geographical source regions marked by air mass back trajectories. The comparison between pure and mixed Icelandic dust samples (i.e., aerosols containing Icelandic dust along with natural and/or anthropogenic components) revealed the occurrence of different mixing situations. Comparison with Icelandic soils proved the existence of dilution effects related to the emission and the transport processes.

Diversity of microbial phototrophs and heterotrophs in Icelandic biocrusts and their role in phosphorus-rich Andosols

Icelandic biocrusts are unique micro-ecosystems, considering their origin from volcanic material as a mineral base. However, little is known about their chemistry and diversity of microorganisms. Being phosphorus (P)-rich, Icelandic soils contribute to the global P cycling. Therefore, here, we focused on investigating P content, P pools, microbial biomass P (Pmic) and potential phosphatase activity along an altitude gradient (11–157 m a.s.l.) stretching away from the sea coast. Total P (Ptotal) content in the studied biocrusts and soils varied between 982 and 1571 mg kg−1 and Pmic, measured in biocrusts, constituted only a minor fraction <0.2% of Ptotal. Sequential P fractionation revealed the dominance of moderately labile P in biocrusts across the sites. Additionally, basic physicochemical properties were measured in biocrusts, and contents of total carbon (TC) and total nitrogen (TN) were positively correlated to Pmic and potential phosphatase activity.Diversity and abundance of microbial phototrophs in the studied biocrusts were assessed by morphological observations using light and epifluorescence microscopy. Microphototrophic communities were dominated by eukaryotic microalgae (e.g. Chlorella, Coccomyxa, Stichococcus) including diatoms (e.g. Pinnularia and Eunotia) and the highest cell biovolume was recorded in the site located at the sea coast. Furthermore, the majority of cyanobacteria belonged to filamentous forms, such as Microcoleus, Leptolyngbya, Phormidesmis and Stenomitos. In addition, the majority of fungal strains isolated from the studied biocrusts belonged to Ascomycota (e.g. Penicillium, Fusarium, Truncatella) and Zygomycota (e.g. Mucor, Mortierella).Overall, this study provides for the first time a comprehensive description of microbial community composition and P distribution in Icelandic biocrusts, which were previously overlooked.

Evaluating the carbon sequestration potential of volcanic soils in southern Iceland after birch afforestation

Abstract. Afforestation is a strategy to sequester atmospheric carbon in the terrestrial system and to enhance ecosystem services. Iceland's large areas of formerly vegetated and now degraded ecosystems therefore have a high potential to act as carbon sinks. Consequently, the ecological restoration of these landscape systems is part of climate mitigation programmes supported by the Icelandic government. The aim of this study was to explore the change in the soil organic carbon (SOC) pools and to estimate the SOC sequestration potential during the re-establishment of birch forest on severely degraded land. Differently aged afforested mountain birch sites (15, 20, 25 and 50 years) were compared to sites of severely degraded land, naturally growing remnants of mountain birch woodland and grasslands which were re-vegetated using fertilizer and grass seeds 50 years ago. The soil was sampled to estimate the SOC stocks and for physical fractionation to characterize the quality of the SOC. The results of our study show that the severely degraded soils can potentially sequester an additional 20 t C ha−1 (0–30 cm) to reach the SOC stock of naturally growing birch woodlands. After 50 years of birch growth, the SOC stock is significantly lower than that of a naturally growing birch woodland, suggesting that afforested stands could sequester additional SOC beyond 50 years of growth. The SOC fractionation revealed that at all the tested sites most of the carbon was stored in the &lt;63 µm fraction. However, after 50 years of birch growth on severely degraded soils the particulate organic matter (POM) fraction was significantly enriched most (+12 t POM-C ha−1) in the top 30 cm. The study also found a doubling of the dissolved organic carbon (DOC) concentration after 50 years of birch growth. Therefore and due to the absence of any increase in the tested mineral-associated SOC fractions, we assume that the afforestation process evokes a carbon deposition in the labile SOC pools. Consequently, parts of this plant-derived, labile SOC may be partly released into the atmosphere during the process of stabilization with the mineral soil phases in the future. Our results are limited in their scope since the selected sites do not fully reflect the heterogeneity of landscape evolution and the range of soil degradation conditions. As an alternative, we suggest using repeated plot measurements instead of space-for-time substitution approaches for testing C changes in severely degraded volcanic soils. Our findings clearly show that detailed measurements on the SOC quality are needed to estimate the SOC sequestration potential of restoration activities on severely degraded volcanic soils, rather than only measuring SOC concentration and SOC stocks.

Can Volcanic Dust Suspended From Surface Soil and Deserts of Iceland Be Transferred to Central Balkan Similarly to African Dust (Sahara)?

In this work we use chemical fingerprints as characteristics ratios of specific crustal elements Ca/Al, Fe/Al, K/Al, Mg/Al, Mn/Al, Ca/Fe and Mg/Fe to investigate the long-range transport of volcanic aerosols which are entering the atmosphere in suspended and resuspended processes from Icelandic deserts and hot spots in remote areas in Iceland and transmitted to the central Balkan area (Belgrade). For this purpose, backward trajectories from Belgrade (=44°48’; =20°28’) in 2012 and 2013, simultaneous with atmospheric aerosols measurements, were calculated by using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. We found that about 17% of air masses passed over Icelandic territory and arrived to Balkan area. In almost all of these episodes ratios of some investigated elements in suburban aerosols of Balkan area corresponded to the ratios of elements investigated in surface soil of the Rangárvellir area - South Iceland in the vicinity of volcanoes. We identified several episodes, such as 6 – 8 August 2012, 2 – 6 June 2013, 26 – 28 June 2013, and 18 – 20 September 2013, with the characteristic ratios of the highest number of investigated elements in atmospheric aerosol of central Balkan corresponding to ratios from Icelandic soil material. This study provides evidence that Icelandic dust can travel long distances showing the importance of High Latitude Dust sources.

The weathering of volcanic tephra and how they impact histosol development. An example from South East Iceland

Little is known about the impact of tephra deposits from explosive volcanic eruptions on soil formation and weathering processes in organic soils. The weathering of tephra of basaltic and rhyolitic origin and their impact on Icelandic histosols were studied through a combination of physical, chemical and mineralogical analyses. Two sampling sites were selected according to the presence of the light coloured rhyolitic tephra from the Öræfajökull eruption in 1362 CE and a dark-coloured basaltic Veiðivötn tephra from 1477 CE in the volcanically active area south of Vatnajökull in South East Iceland.The determining factor of pedogenesis in the investigated histosols is the OM, but the influence of tephra and aeolian material from external sources must be taken into consideration. The soils are the result of altered plant residues and volcanic material (tephra and aeolian material). Plant remnants, as well as the soil itself, are protected from decomposition by the prevailing anaerobic conditions, a low soil pH and the repeated addition of inorganic matter. Clay formation is low, while metal-humus complexes are predominant. Feo/Fed ratios indicated a generally low degree of weathering, being higher close to the basaltic tephra.The mineralogy was dominated by plagioclase and pyroxene, with quartz and zeolite as minor components. In contrast to previous research on Icelandic soils, our investigations revealed layer silicates at both sites. While we found evidence of smectite in the soils at Kálfafell, hydroxy interlayered minerals were found at Reynivellir. In the basaltic tephra, traces of layer silicates could be verified. In contrast, the rhyolitic tephra did not show any pedogenic minerals, suggesting that it had hardly altered since its deposition in 1362 CE. It is not the chemical composition of the inorganic parent material, but the location that may be an influencing factor on the formation of clay minerals in the investigated histosols.

Functional diversity of Collembola is reduced in soils subjected to short‐term, but not long‐term, geothermal warming

AbstractHuman activities have caused global changes of atmospheric chemistry resulting in increased temperature especially in the colder regions of the northern hemisphere. Since warming of the environment can have drastic effects on terrestrial ecosystems it is important to experimentally evaluate the extent of such effects in long‐term field‐based experiments. In this study we make use of both recent (short‐term) and long‐term geothermal warming of Icelandic soils to examine the responses of Collembola, an ecologically important group of soil invertebrates, to warming.On the basis of metabolic scaling theory, we hypothesized that species of small size would be more successful in warmed soils than species of larger size. Further we expected that top‐soil‐dwelling species would benefit more from warming than deep‐soil‐dwelling species. In order to test these hypotheses we sampled Collembola along replicated gradients of increasing temperature in areas that had been heated for about 6 years and more than 50 years respectively. Collembola were identified to species level, counted and the community‐weighted mean trait scores for six functional and ecological traits were calculated.Results show that both short‐term and long‐term soil warming caused a shift towards a higher relative abundance of species with small body size. Furthermore, abundance of top‐soil‐dwelling Collembola tended to increase after short‐term warming, but the opposite was observed after long‐term warming.Using trait‐based diversity indices (FRic and RaoQ), we show that functional richness and diversity of Collembola communities was significantly reduced (almost halved) as a result of short‐term soil warming to about 10°C above normal, but this effect was not detected in plots equally warmed for more than 50 years. This indicates that the functional diversity of Collembola communities have high resilience towards soil warming in a long‐term perspective.Aplain language summaryis available for this article.

Iron and silicon isotope behaviour accompanying weathering in Icelandic soils, and the implications for iron export from peatlands

Incipient warming of peatlands at high latitudes is expected to modify soil drainage and hence the redox conditions, which has implications for Fe export from soils. This study uses Fe isotopes to assess the processes controlling Fe export in a range of Icelandic soils including peat soils derived from the same parent basalt, where Fe isotope variations principally reflect differences in weathering and drainage. In poorly weathered, well-drained soils (non-peat soils), the limited Fe isotope fractionation in soil solutions relative to the bulk soil (Δ57Fesolution-soil=−0.11±0.12‰) is attributed to proton-promoted mineral dissolution. In the more weathered poorly drained soils (peat soils), the soil solutions are usually lighter than the bulk soil (Δ57Fesolution-soil=−0.41±0.32‰), which indicates that Fe has been mobilised by reductive mineral dissolution and/or ligand-controlled dissolution. The results highlight the presence of Fe-organic complexes in solution in anoxic conditions. An additional constraint on soil weathering is provided by Si isotopes. The Si isotope composition of the soil solutions relative to the soil (Δ30Sisolution-soil=0.92±0.26‰) generally reflects the incorporation of light Si isotopes in secondary aluminosilicates. Under anoxic conditions in peat soils, the largest Si isotope fractionation in soil solutions relative to the bulk soil is observed (Δ30Sisolution-soil=1.63±0.40‰) and attributed to the cumulative contribution of secondary clay minerals and amorphous silica precipitation. Si supersaturation in solution with respect to amorphous silica is reached upon freezing when Al availability to form aluminosilicates is limited by the affinity of Al for metal–organic complexes. Therefore, the precipitation of amorphous silica in peat soils indirectly supports the formation of metal–organic complexes in poorly drained soils. These observations highlight that in a scenario of decreasing soil drainage with warming high latitude peatlands, Fe export from soils as Fe-organic complexes will increase, which in turn has implications for Fe transport in rivers, and ultimately the delivery of Fe to the oceans.

The influence of weathering and soil organic matter on Zn isotopes in soils

Zinc is an essential micronutrient that is ultimately released during mineral weathering. In soils, organic matter plays a key role in influencing Zn partitioning and therefore on Zn biogeochemical cycling. Soil organic matter is partitioned between carbon that is more readily available for decomposition by microorganisms, and more stable carbon transiently preserved from decomposition. The role of the stable pool of soil organic matter on Zn biogeochemical cycling remains poorly understood. The pool of stable carbon is controlled by combination with mineral constituents or is material that is intrinsically resistant to decomposition. The Zn stable isotopes are fractionated by interactions between Zn and soil mineral and organic constituents. This study reports the Zn isotope composition of five Icelandic soil profiles derived from the same parent basalt and characterized by contrasting degrees of weathering and organic matter content (δ66Zn=+0.10±0.05 to +0.35±0.02‰), the distribution of reactive mineral constituents available to form associations with soil organic matter, and the amount of stable organic carbon. Throughout these soils, the δ66Zn isotope variations are little influenced by mineral constituents, but rather by soil organic matter content. These data suggest that a combination of organic matter accumulation and Zn loss by leaching is required to explain the observed decrease in Zn concentration in soils and lighter soil δ66Zn with increasing organic carbon content. These results suggest that the presence of stable organic carbon in soils provides a pool of light Zn, attributed to the Zn isotope signature of organic matter partially preserved from decomposition. Crucially, this stable organic carbon pool may also contribute to the formation of the light Zn isotope sink reported in organic-rich marine sediments, a key output required to explain the oceanic mass balance of Zn isotopes.

The Whole World Is One Atom Station: Laxness, the Cold War, Postcolonialism, and the Economic Crisis in Iceland

INTRODUCTION Until late 2013, on the website and the menu of Islenski barinn in Reykjavik (a trendy cafe in Austurvollur, the site of the Icelandic parliament), one could read of a dramatic episode. (1) On January 22, 2009, a crowd gathered in front of the parliament and demanded the resignation of the government, after the local banks had declared bankruptcy and an agreement to repay the Icesave debt had been signed (Bergmann 2014, 140-6). At one point during the demonstration, as agitation increased and tensions rose, the police used tear gas to disperse the crowd. At the cafe, shocked customers and waiters looked at the scene, until someone opened the door to the demonstrators in order to protect them from the police's actions. After closing time, the staff of Islenski barinn started discussing the events and were struck by one analogy. Icelanders had not witnessed the use of tear gas since March 30, 1949, when a crowd had gathered in the same square to protest against Iceland joining the North Atlantic Treaty Organization (NATO). The people of Islenski barinn thought it seemed like a ghost from the past had returned in the peaceful Icelandic society. The fact that the 2009 Austurvollur episode ended up in a menu, accompanied by a reference to the 1949 events, betokens the parallel shocks such experiences visited upon the Icelandic population. Such a parallel can be better exposed through a literary work by Iceland's Nobel laureate Halldor Laxness and its Cold War and postcolonial implications. Laxness's novel Atomstodin (1948; The Atom Station, 1961) gives a vivid portrait of the starting phase of a network of power relations and economic-ideological positions that arose in postwar Iceland and developed throughout the twentieth century up to the economic crisis that hit the country in 2008. In so doing, the novel strikes the modern reader for its relevance and the similarity between the events it somehow anticipated (such as the protests against Iceland's entrance into NATO, which occurred one year after its publication) and the conditions of Iceland after the economic crisis. In order to discuss this relationship between the novel and the contemporary period, this article will start with the socio-political context in which Atomstodin arose, and then focus on two aspects, namely its nature as a novel of the Cold War and as a postcolonial narrative. Within this context, I will also address Atomstodin's relationship to nationalism and its relevance as a postnational novel. In the final part of the article, these perspectives will be used to inform a reading of Atomstodin in the light of the recent economic crisis in Iceland. ATOMSTODIN AND ITS CONTEXT Atomstodin tells the story of Ugla, a young woman from the north of Iceland. At the beginning of the novel, she has just started working as a maid at the home of member of parliament Bui Arland, where US army personnel and local politicians meet to discuss building an American military base on Icelandic soil. Ugla has made plans for her stay in Reykjavik, as she intends to take harmonium lessons in order to play in her village's church. In reality, one soon understands that her trip has an existential reason. A peculiar organist starts teaching her, but he and Ugla spend most of the time discussing life and philosophy with his friends, among others, two gods, Benjamin atomskald (atomic poet) and Briljantin (Brilliantine), a prostitute named Kleopatra, and a mysterious, self-conscious policeman. After one of these lessons, the policeman and Ugla spend the night together, an episode that results in a pregnancy. Ugla goes home to give birth to a baby girl, but after a while, she returns to Reykjavik, first to Bui Arland (with whom she has a quick affair), later to the organist, and finally to the policeman, who has ended up in jail. However, she decides to wait for him to be released so that they can start a life together. During its early reception, Atomstodin was considered a pamphlet in disguise and (mis)treated as such. …

Editorial

Because of the systemic connections between soils and many other issues, the attention that is actually paid to soil issues is far greater than is immediately apparent. In many countries, scientists, public servants and politicians are debating sequestration of carbon in soils, deforestation and other land management matters which impact the soil, the atmosphere and the human interests bound up in these.This special edition arose from a workshop held in Iceland in 2012, supported by the Australian Research Council and hosted by the Icelandic Soils Service. It brought together researchers and practitioners with expertise and interest in the human dimensions of natural resource governance. An aim was to generate fresh perspectives on how to govern human behaviour, to improve the sustainability and fairness of our use of the land. The team included experts and practitioners in soil issues, community engagement, psychology, sociology, economics, law and other disciplines from many countries. The papers in this special edition reflect issues that have also been canvassed in other investigations. These papers provide some different perspectives as well as reinforcing some common themes.

Molybdenum isotope fractionation in soils: Influence of redox conditions, organic matter, and atmospheric inputs

Molybdenum isotope fractionation accompanying soil development is studied across three pedogenic gradients encompassing a range of controlling factors. These factors include variable redox conditions, organic matter content, Fe and Mn oxy(hydr)oxide content, mineral composition, degree of weathering, pH, type and amount of atmospheric inputs, age, climate, and underlying rock type. Soil profiles from the island of Maui (Hawaii) along a precipitation gradient ranging from 850 to 5050mm mean annual precipitation show a decrease in average soil δ98Mo from −0.04±0.11‰ at the driest, most oxic site, which is indistinguishable from the basalt parent material (−0.09±0.08‰), to −0.33±0.10‰ at the wettest, most reducing site. A suite of 6 Icelandic soils display a broad trend with heavier δ98Mo values (up to +1.50±0.09‰) in soil horizons that are more weathered and have higher organic matter content. Selective extractions of Mo from different soil components indicate that the association with organic matter and silicate or Ti-oxide residue dominates retention of Mo in these soils, with adsorption on Fe and Mn oxy(hydr)oxides playing a lesser role. Across all basaltic soils, δ98Mo values are lighter in soils that exhibit the most net Mo loss relative to the parent material, and δ98Mo values are heavier in soils that exhibit net Mo gains. A well-drained regolith profile in the Luquillo Mountains of Puerto Rico developed on quartz diorite shows heavier δ98Mo values than the parent material (up to +0.71±0.10‰ with an integrated profile average of +0.28±0.10‰) in soil and shallower saprolite, despite overall moderate loss of 28% of Mo relative to the bedrock. However, the deeper saprolite is unfractionated from bedrock (−0.01±0.10‰, quartz diorite bedrock) indicating that rock weathering dissolution processes and secondary clay formation do not fractionate Mo isotopes. Our data suggest that the Mo mass balance and isotope composition of soils are controlled by redox conditions, organic matter, and atmospheric inputs. In this way Mo isotopes have the potential to react to and record climate driven changes in the weathering environment. The presence of both isotopically light and heavy Mo (relative to parent material) across all sites and within individual soil profiles suggests that it is normal for multiple fractionation mechanisms to operate under the open-system conditions of soils.

Magnesium retention on the soil exchange complex controlling Mg isotope variations in soils, soil solutions and vegetation in volcanic soils, Iceland

Understanding the biogeochemical cycle of magnesium (Mg) is not only crucial for terrestrial ecology, as this element is a key nutrient for plants, but also for quantifying chemical weathering fluxes of Mg and associated atmospheric CO2 consumption, requiring distinction of biotic from abiotic contributions to Mg fluxes exported to the hydrosphere. Here, Mg isotope compositions are reported for parent basalt, bulk soils, clay fractions, exchangeable Mg, seasonal soil solutions, and vegetation for five types of volcanic soils in Iceland in order to improve the understanding of sources and processes controlling Mg supply to vegetation and export to the hydrosphere. Bulk soils (δ26Mg=−0.40±0.11‰) are isotopically similar to the parent basalt (δ26Mg=−0.31‰), whereas clay fractions (δ26Mg=−0.62±0.12‰), exchangeable Mg (δ26Mg=−0.75±0.14‰), and soil solutions (δ26Mg=−0.89±0.16‰) are all isotopically lighter than the basalt. These compositions can be explained by a combination of mixing and isotope fractionation processes on the soil exchange complex. Successive adsorption–desorption of heavy Mg isotopes leads to the preferential loss of heavy Mg from the soil profile, leaving soils with light Mg isotope compositions relative to the parent basalt. Additionally, external contributions from sea spray and organic matter decomposition result in a mixture of Mg sources on the soil exchange complex. Vegetation preferentially takes up heavy Mg from the soil exchange complex (Δ26Mgplant-exch=+0.50±0.09‰), and changes in δ26Mg in vegetation reflect changes in bioavailable Mg sources in soils. This study highlights the major role of Mg retention on the soil exchange complex amongst the factors controlling Mg isotope variations in soils and soil solutions, and demonstrates that Mg isotopes provide a valuable tool for monitoring biotic and abiotic contributions of Mg that is bioavailable for plants and is exported to the hydrosphere.

Bioremediation trial on aged PCB-polluted soils—a bench study in Iceland

Polychlorinated biphenyls (PCBs) pose a threat to the environment due to their high adsorption capacity to soil organic matter, stability and low reactivity, low water solubility, toxicity and ability to bioaccumulate. With Icelandic soils, research on contamination issues has been very limited and no data has been reported either on PCB degradation potential or rate. The goals of this research were to assess the bioavailability of aged PCBs in the soils of the old North Atlantic Treaty Organization facility in Keflavík, Iceland and to find the best biostimulation method to decrease the pollution. The effectiveness of different biostimulation additives (N fertiliser, white clover and pine needles) at different temperatures (10 and 30 °C) and oxygen levels (aerobic and anaerobic) were tested. PCB bioavailability to soil fauna was assessed with earthworms (Eisenia foetida). PCBs were bioavailable to earthworms (bioaccumulation factor 0.89 and 0.82 for earthworms in 12.5 ppm PCB soil and in 25 ppm PCB soil, respectively), with less chlorinated congeners showing higher bioaccumulation factors than highly chlorinated congeners. Biostimulation with pine needles at 10 °C under aerobic conditions resulted in nearly 38 % degradation of total PCBs after 2 months of incubation. Detection of the aerobic PCB degrading bphA gene supports the indigenous capability of the soils to aerobically degrade PCBs. Further research on field scale biostimulation trials with pine needles in cold environments is recommended in order to optimise the method for onsite remediation.