Iceland border the Arctic with cold maritime climate and a large proportion of the land placed at highland plateaus. About 1100 years of human disturbance, such as grazing and wood harvesting, has ...left much of the island's ecosystems in a poor state, ranging from barren deserts to areas with altered vegetative composition and degraded soils. We constructed a novel resilience-based model (RBC-model) for current land condition in Iceland to test which and how factors, including elevation, slope characteristics, drainage, and proximity to volcanic activity, influence the resilience and stability of ecosystems to human disturbances. We tested the model by randomly placing 500 sample areas (250 x 250 m) all over the country and obtaining values for each factor and current land conditions for each area from existing databases and satellite images. Elevation and drainage explained the largest portions of variability in land condition in Iceland, while both proximity to volcanic activity and the presence of scree slopes also yielded significant relationships. Overall, the model explained about 65% of the variability. The model was improved (R2 from 0.65 to 0.68) when the country was divided into four broadly defined regions. Land condition at the colder northern peninsulas was poorer at lower elevations compared to inland positions. This novel RBC model was successful in explaining differences in present land condition in Iceland. The results have implication for current land use management, especially grazing, suggesting that management should consider elevation, drainage, slopes and location within the country in addition to current land condition.
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•Grass swales maintain their, infiltration and drainage capacity during winter.•Dense, mat-like roots improved porosity and minimized frost heave.•Sparsely vegetated surfaces are ...prone to heave, cracks and deep frost formation.•Shallow, intermittent snow cover leads to freeze–thaw and soil frost.•SuDS design and plant selection criteria need to consider frost susceptibility.
Sustainable Urban Drainage Systems (SuDS) promote environmental protection and climate resilience. SuDS implementation in cold climates faces concerns of impaired hydrological function due to infiltration-reducing frost. The goal of this research was to assess the seasonal variations in infiltration and how different surface covers prevalent in and near coastal cities respond to frequent rain-on-snow and freeze–thaw cycles. A total of 28 constant head infiltration measurements were conducted over a period of 28 months in Urridaholt in Gardabaer, Iceland (64° 4′18.46″ N, 21° 54′37.11″ W) in a grass swale, lupine, and barren terrains. All test locations exhibited infiltration-inhibiting frost in winter, whose severity increased with frequent snow and freeze–thaw cycles. The grass swale resisted structural deformations resulting from frost, which was attributed to the high near-surface porosity within the intertwined root layer and the high drainage capacity of the underlying soil. The sparsely vegetated lupine and the barren area experienced severe frost heaving and cracking, and soil structural collapse which led to bypass flow upon thawing. The non-vegetated site had 30 to 50 times lower infiltration during winter (19 mm h−1) compared to the grass swale and lupine field (630- and 890-mm h−1, respectively), and twenty times lower during summer and fall (45 mm h−1 vs. ∼ 1000 mm h−1). The study concludes that frequent warming and cooling renders soils particularly vulnerable to frost. Vegetation plays an instrumental role in maintaining the hydrological functions of SuDS in winter. Therefore, the greening of urban centers is an important step towards climate resiliency. Plant selection and SuDS design criteria need to account for cold climate hydrological performance. In that regard, plants that limit sunlight and fully shed their vegetation in winter, such as the invasive lupine, can potentially contribute to frost formation and increase runoff generation.
Icelandic dust sources are known to be highly active, yet there exist few model simulations of Icelandic dust that could be used to assess its impacts on the environment. We here present estimates of ...dust emission and transport in Iceland over 27 years (1990–2016) based on FLEXDUST and FLEXPART simulations and meteorological re-analysis data. Simulations for the year 2012 based on high-resolution operational meteorological analyses are used for model evaluation based on PM2. 5 and PM10 observations in Iceland. For stations in Reykjavik, we find that the spring period is well predicted by the model, while dust events in late fall and early winter are overpredicted. Six years of dust concentrations observed at Stórhöfði (Heimaey) show that the model predicts concentrations of the same order of magnitude as observations and timing of modelled and observed dust peaks agrees well. Average annual dust emission is 4.3 ± 0.8 Tg during the 27 years of simulation. Fifty percent of all dust from Iceland is on average emitted in just 25 days of the year, demonstrating the importance of a few strong events for annual total dust emissions. Annual dust emission as well as transport patterns correlate only weakly to the North Atlantic Oscillation. Deposition amounts in remote regions (Svalbard and Greenland) vary from year to year. Only limited dust amounts reach the upper Greenland Ice Sheet, but considerable dust amounts are deposited on Icelandic glaciers and can impact melt rates there. Approximately 34 % of the annual dust emission is deposited in Iceland itself. Most dust (58 %), however, is deposited in the ocean and may strongly influence marine ecosystems.
Iceland has the largest area of volcaniclastic sandy desert on Earth or 22,000 km super(2). The sand has been mostly produced by glacio-fluvial processes, leaving behind fine-grained unstable ...sediments which are later re-distributed by repeated aeolian events. Volcanic eruptions add to this pool of unstable sediments, often from subglacial eruptions. Icelandic desert surfaces are divided into sand fields, sandy lavas and sandy lag gravel, each with separate aeolian surface characteristics such as threshold velocities. Storms are frequent due to Iceland's location on the North Atlantic Storm track. Dry winds occur on the leeward sides of mountains and glaciers, in spite of the high moisture content of the Atlantic cyclones. Surface winds often move hundreds to more than 1000 kg m super(-1) per annum, and more than 10,000 kg m super(-1) have been measured in a single storm. Desertification occurs when aeolian processes push sand fronts and have thus destroyed many previously fully vegetated ecosystems since the time of the settlement of Iceland in the late ninth century. There are about 135 dust events per annum, ranging from minor storms to >300,000 t of dust emitted in single storms. Dust production is on the order of 30-40 million tons annually, some traveling over 1000 km and deposited on land and sea. Dust deposited on deserts tends to be re-suspended during subsequent storms. High PM sub(10) concentrations occur during major dust storms. They are more frequent in the wake of volcanic eruptions, such as after the Eyjafjallajokull 2010 eruption. Airborne dust affects human health, with negative effects enhanced by the tubular morphology of the grains, and the basaltic composition with its high metal content. Dust deposition on snow and glaciers intensifies melting. Moreover, the dust production probably also influences atmospheric conditions and parameters that affect climate change.
Dust particles from high latitudes have a potentially large local, regional, and global significance to climate and the environment as short-lived climate forcers, air pollutants, and nutrient ...sources. Identifying the locations of local dust sources and their emission, transport, and deposition processes is important for understanding the multiple impacts of high-latitude dust (HLD) on the Earth’s systems. Here, we identify, describe, and quantify the source intensity (SI) values, which show the potential of soil surfaces for dust emission scaled to values 0 to 1 concerning globally best productive sources, using the Global Sand and Dust Storms Source Base Map (G-SDS-SBM). This includes 64 HLD sources in our collection for the northern (Alaska, Canada, Denmark, Greenland, Iceland, Svalbard, Sweden, and Russia) and southern (Antarctica and Patagonia) high latitudes. Activity from most of these HLD sources shows seasonal character. It is estimated that high-latitude land areas with higher (SI ≥ 0.5), very high (SI ≥ 0.7), and the highest potential (SI ≥ 0.9) for dust emission cover > 1 670 000 km2 , > 560 000 km2 , and > 240 000 km2 , respectively. In the Arctic HLD region (≥ 60◦ N), land area with SI ≥ 0.5 is 5.5 % (1 035 059 km2), area with SI ≥ 0.7 is 2.3 % (440 804 km2), and area with SI ≥ 0.9 is 1.1 % (208 701 km2). Minimum SI values in the northern HLD region are about 3 orders of magnitude smaller, indicating that the dust sources of this region greatly depend on weather conditions. Our spatial dust source distribution analysis modeling results showed evidence supporting a northern HLD belt, defined as the area north of 50◦ N, with a “transitional HLD-source area” extending at latitudes 50–58◦ N in Eurasia and 50–55◦ N in Canada and a “cold HLD-source area” including areas north of 60◦ N in Eurasia and north of 58◦ N in Canada, with currently “no dust source” area between the HLD and low-latitude dust (LLD) dust belt, except for British Columbia. Using the global atmospheric transport model SILAM, we estimated that 1.0 % of the global dust emission originated from the high-latitude regions. About 57 % of the dust deposition in snow- and ice-covered Arctic regions was from HLD sources. In the southern HLD region, soil surface conditions are favorable for dust emission during the whole year. Climate change can cause a decrease in the duration of snow cover, retreat of glaciers, and an increase in drought, heatwave intensity, and frequency, leading to the increasing frequency of topsoil conditions favorable for dust emission, which increases the probability of dust storms. Our study provides a step forward to improve the representation of HLD in models and to monitor, quantify, and assess the environmental and climate significance of HLD.
Iceland is a highly active source of natural dust.
Icelandic dust has the potential to directly affect the climate via
dust–radiation interaction and indirectly via dust–cloud interaction,
the ...snow/ice albedo effect and impacts on biogeochemical cycles. The impacts of
Icelandic dust depend on its mineralogical and chemical composition.
However, a lack of data has prevented an accurate assessment of the role of
Icelandic dust in the Earth system. Here, we collected surface sediment
samples from five major Icelandic dust hotspots. Dust aerosols were
generated and suspended in atmospheric chambers, and PM10 and PM20
fractions were collected for further analysis. We found that the dust
samples primarily consist of amorphous basaltic materials ranging from 8 wt %
(from the Hagavatn hotspot) to 60 wt %–90 wt % (other hotspots). Samples
had relatively high total Fe content (10 wt %–13 wt %). Sequential extraction
of Fe to determine its chemical form shows that dithionite Fe (Fe oxides
such as hematite and goethite) and ascorbate Fe (amorphous Fe) contribute
respectively 1 %–6 % and 0.3 %–1.4 % to the total Fe in Icelandic dust. The
magnetite fraction is 7 %–15 % of total Fe and 1 %–2 wt % of PM10,
which is orders of magnitude higher than in mineral dust from northern Africa.
Nevertheless, about 80 %–90% of the Fe is contained in pyroxene and
amorphous glass. The initial Fe solubility (ammonium acetate extraction at
pH 4.7) is from 0.08 % to 0.6 %, which is comparable to low-latitude dust such
as that from northern Africa. The Fe solubility at low pH (i.e. pH 2) is
significantly higher than typical low-latitude dust (up to 30 % at pH 2
after 72 h). Our results revealed the fundamental differences in
composition and mineralogy of Icelandic dust from low-latitude dust. We
attribute these differences to the low degree of chemical weathering, the
basaltic composition of the parent sediments and glacial processes.
Icelandic dust contributes to the atmospheric deposition of soluble Fe and
can impact primary productivity in the North Atlantic Ocean. The distinct
chemical and mineralogical composition, particularly the high magnetite
content (1 wt %–2 wt %), indicates a potentially significant impact of
Icelandic dust on the radiation balance in the subpolar and polar regions.
The Nordic Centre of Excellence CRAICC (Cryosphere–Atmosphere Interactions in a Changing Arctic Climate), funded by NordForsk in the years 2011–2016, is the largest joint Nordic research and ...innovation initiative to date, aiming to strengthen research and innovation regarding climate change issues in the Nordic region. CRAICC gathered more than 100 scientists from all Nordic countries in a virtual centre with the objectives of identifying and quantifying the major processes controlling Arctic warming and related feedback mechanisms, outlining strategies to mitigate Arctic warming, and developing Nordic Earth system modelling with a focus on short-lived climate forcers (SLCFs), including natural and anthropogenic aerosols. The outcome of CRAICC is reflected in more than 150 peer-reviewed scientific publications, most of which are in the CRAICC special issue of the journal Atmospheric Chemistry and Physics. This paper presents an overview of the main scientific topics investigated in the centre and provides the reader with a state-of-the-art comprehensive summary of what has been achieved in CRAICC with links to the particular publications for further detail. Faced with a vast amount of scientific discovery, we do not claim to completely summarize the results from CRAICC within this paper, but rather concentrate here on the main results which are related to feedback loops in climate change–cryosphere interactions that affect Arctic amplification.
The major element mobility within soil profiles of brown to gleyic Andosols that developed under diverse climatic conditions in Iceland is assessed. The volcanic soils were selected from areas with ...good monitoring of annual temperature and precipitation and the degree of weathering and elemental behavior is compared. Icelandic soils are subject to high fluxes of aeolian dust, and at times, to tephra ejecta from volcanic eruptions. The source of dust input is assessed for each profile based on comparison of the chemical signatures found in the less weathered upper horizons with those of volcanic systems supplying material to source areas. Results show that TiO2, Al2O3 and Fe2O3(T) and MnO are the least mobile species and generally found enriched within more mature horizons. The mobile base cations MgO, CaO and Na2O are depleted in these horizons as a result of chemical weathering during pedogenesis. Soils developed in colder climatic conditions with mean annual temperature (MAT) ∽−1°C give values for the Chemical Index of Weathering (CIW) of 37–45 that reflect only weak chemical weathering. Soils developed in milder climates (MAT=2–4°C) are more strongly affected by weathering (CIW=50–77). The parent material has CIW values of ∽37. Temperature is demonstrated as the dominant variable exerting control on the extent of weathering, with only minor mobilization following the incipient near-surface weathering stage. A robust linear relationship is found between CIW and model MAT (MAT=0.21CIW −8.93, R2=0.81). This climofunction can deliver proxy climate estimations from volcanic soils and paleosols of basaltic origin in cool to subarctic conditions (−2 to +6°C).
► We examine climate control on major element mobilization in Icelandic andosols. ► Mg, Ca, Na and Si are mobile, Ti, Al, Fe and Mn immobile relative to basalt parent. ► K and P show variable behavior, mostly due to fixation by organic matter. ► Incipient near-surface mobilization strongly exceeds post-burial weathering. ► A climofunction is given from correlation of weathering extent with temperature.
Volcanic eruptions can generate widespread deposits of ash that are subsequently subjected to erosive forces which causes detrimental effects on ecosystems. We measured wind erosion of the freshly ...deposited Eyjafjallajökull ash at a field site the first summer after the 2010 eruption. Over 30 wind erosion events occurred (June-October) at wind speeds > 10 m s(-1) in each storm with gusts up to 38.7 m s(-1). Surface transport over one m wide transect (surface to 150 cm height) reached > 11,800 kg m(-1) during the most intense storm event with a rate of 1,440 kg m(-1) hr(-1) for about 6½ hrs. This storm is among the most extreme wind erosion events recorded on Earth. The Eyjafjallajökull wind erosion storms caused dust emissions extending several hundred km from the volcano affecting both air quality and ecosystems showing how wind erosion of freshly deposited ash prolongs impacts of volcanic eruptions.
•Iceland supports huge populations of breeding waders in agricultural landscapes.•Breeding wader density increases with amount of wetland in surrounding landscapes.•In more fertile lowland areas, ...wader densities decline with amount of agriculture.•In less fertile upland areas, wader densities increase with amount of agriculture.
The capacity of different landscapes to sustain viable populations depends on the spatial and temporal availability of key population-specific resources. Heterogeneous landscapes provide a wider range of resources and often sustain higher levels of biodiversity than homogeneous ones. Across the globe, agricultural expansion has resulted in large-scale homogenisation of landscapes with associated declines in many taxa. However, during the early stages of agricultural development, in terms of area and intensity, increased landscape heterogeneity and changes in local productivity through fertilizer inputs can potentially increase resource availability for some species. Agriculture in Iceland is currently neither highly intensive nor extensive, and primarily occurs as hayfields (>90% of agricultural land) embedded within a mosaic of semi-natural wetlands and heaths. These landscapes support internationally important breeding populations of several wader species but the role of agricultural land in promoting or constraining breeding wader densities is currently unknown. Understanding the relationship between cultivation and wader populations is important as the area of cultivated land is predicted to expand in Iceland in near future, largely through conversion of the remaining semi-natural wetlands. Here we (a) quantify relationships between breeding wader densities in lowland Iceland and the amount of cultivated land and wetland in the surrounding landscape using density estimates from 200 transects in common semi-natural habitats, (b) assess the extent to which cultivated land affects wader densities in these landscapes, and the potential effects of future agricultural expansion at the expense of wetlands on wader populations. Wader densities in semi-natural habitats were consistently greater when surrounding landscapes had more wetland at scales ranging from 500 m to 2500 m, indicating the importance of wetland availability. However, the effects of cultivated land in the surrounding landscape varied with altitude (ranging from 0 to 200 m); in low-lying coastal areas, wader numbers decline with increasing amounts of cultivated land (and the lowest densities (<1 km2) occur in areas dominated with cultivated land), the inverse occurs at higher altitudes (>100 m a.s.l., where lowest densities occur in areas without cultivated land). This suggests that additional resources provided by cultivated land may be more important in the less fertile uplands. Further agricultural conversion of wetlands in low-lying areas of Iceland is likely to be detrimental for breeding waders, but such effects may be less apparent at higher altitudes.
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