Erosional effects on terrestrial resources over the last millennium in Reykjanes, southwest Iceland     

Guðrún Gísladóttir  Egill Erlendsson  Rattan Lal 《Quaternary Research》2010,73(1):20-32

The study presents the effect of soil erosion on vegetation, soil accumulation (SA), SA rate (SAR), soil quality, soil mass, and the soil organic carbon (SOC) pool in Brown Andosols and Histosols in a 24-km² area in southwest Iceland. Undisturbed prehistoric soils were distinguished from disturbed historic soils using tephrochronology. Soil erosion has been severe during historic time (last 1135 yr), resulting in the increase of the soil mass deposited in soils covered by vegetation by a factor of 7.3-9.2 and net loss of soil in unvegetated areas. The SAR correlated positively with SOC sequestration. SOC is easily transported and, given the extensive accumulation of soil, the net effect of burial and subsequent reduction in decomposition is to increase SOC storage. Nevertheless, the increased accumulation and soil depletion has decreased soil quality, including the SOC, and reduced soil resistance to erosion with the depleted SOC contributing to enrichment of atmospheric CO₂. The initial terrestrial disturbance was triggered by anthropogenic land use during the Medieval Warm Period, followed by volcanic activity approximately three centuries later. The combination of harsh climate during the Little Ice Age and drastic anthropogenic perturbations has led to land degradation at a catastrophic scale.  相似文献   

A swash–backwash model of the single epidemic wave     

Cliff AD  Haggett P 《Journal of Geographical Systems》2006,8(3):227-252

While there is a large literature on the form of epidemic waves in the time domain, models of their structure and shape in the spatial domain remain poorly developed. This paper concentrates on the changing spatial distribution of an epidemic wave over time and presents a simple method for identifying the leading and trailing edges of the spatial advance and retreat of such waves. Analysis of edge characteristics is used to (a) disaggregate waves into ‘swash’ and ‘backwash’ stages, (b) measure the phase transitions of areas from susceptible, S, through infective, I, to recovered, R, status (S → I → R) as dimensionless integrals and (c) estimate a spatial version of the basic reproduction number, R ₀. The methods used are illustrated by application to measles waves in Iceland over a 60-year period from 1915 to 1974. Extensions of the methods for use with more complex waves are possible through modifying the threshold values used to define the start and end points of an event.

Peter HaggettEmail:

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Population genetics of cold‐water coral associated Pleustidae (Crustacea,Amphipoda) reveals cryptic diversity and recent expansion off Iceland     

Martin Schwentner  Anne‐Nina Lrz 《Marine Ecology》2021,42(1):e12625

Amphipoda are a diverse and important faunal component of deep‐sea habitats worldwide. However, relatively little is known about species that are associated with cold‐water corals, in particular concerning their genetic diversity, population genetic processes, population differentiation, and potential host specificity. We exemplarily investigate these questions studying three pleustid species—Stenopleustes aff. malmgreni (Boeck, 1871), Stenopleustes aff. nodifera (Sars, 1883) and Neopleustes aff. boecki (Hansen, 1888)—that are associated with cold‐water corals and polychaete assemblages along the Reykjanes Ridge southwest of Iceland. We sequenced mitochondrial COI and performed ddRAD to study thousands of nuclear loci. These species and a pair of morphologically cryptic species within Stenopleustes aff. nodifera were consistently delimited by COI and ddRAD. We conclude that all of our studied species are new to science, raising the number of pleustids reported from cold‐water corals to six. Two species were collected only once, and these species exhibited high levels of inbreeding, suggesting little exchange with other populations, which might be a result of strong host specificity. The other two species were wider distributed, with very low differentiation among populations, even between populations separated by 130 km. These species showed signs of recent population expansions, possibly in relation to changes in the cold‐water coral associated ecosystem (e.g., due to glacial cycles and/or volcanic or geothermal activities). They had lower levels of inbreeding and were each associated with three different host coral species, which might facilitate dispersal and gene flow. Our results show divergent population genetic patterns for the studied pleustid species. These might be attributed to the species’ host specificity and highlight important differences among species with seemingly similar life‐styles. Species diversities appear to be greatly underestimated, limiting our abilities to truly assess the vulnerability of the fauna living in these threatened cold‐water coral habitats.  相似文献   

Late Quaternary glacial and deglacial history of eastern Vestfirdir,Iceland using cosmogenic isotope (36Cl) exposure ages and marine cores     

Sarah M. Principato  slaug Geirsdttir  Gudrún Eva Jhannsdttir  John T. Andrews 《第四纪科学杂志》2006,21(3):271-285

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The crustal structure beneath the northwest fjords, Iceland, from receiver functions and surface waves   总被引：1，自引：0，他引：1  

Z. J. Du  & G. R. Foulger 《Geophysical Journal International》1999,139(2):419-432

Five broad-band seismic stations were operated in the northwest fjords area of Iceland from 1996 to 1998 as part of the Iceland Hotspot project. The structures of the upper 35  km or so beneath these stations were determined by the modelling and joint inversion of receiver functions and regional surface wave phase velocities. More than 40 teleseismic events and a few regional events containing high-quality surface wave trains were used. Although the middle period passband of the seismograms is corrupted by oceanic microseismic noise, which hinders the interpretation of structural details, the inversions reveal the overall features. Many profiles obtained exhibit large velocity gradients in the upper 5  km or so, smaller zero gradients below this, and, at ~23  km depth, a zone 2–4  km thick with higher velocity gradients. The two shallower intervals are fairly consistent with the 'upper' and 'lower' crust, defined by Flovenz (1980 ). The deep zone of enhanced velocity gradient seems to correspond to the sharp reflector first reported by Bjarnason et al . (1993 ) and identified by them as the 'Moho'. However, this type of structure is not ubiquitous beneath the northwest fjords area. The distinctiveness of the three intervals is variable, and in some cases a structure with velocity gradient increasing smoothly with depth is observed. We term these two end-members structures of the first and second types respectively. Structures of the second type correlate with older areas. Substantial variation in fundamental structure is to be expected in Iceland because of the great geological heterogeneity there.  相似文献   

Ice‐cored drumlins at the surge‐type glacier Brúarjökull,Iceland: a transitional‐state landform     

Anders Schomacker  Johannes Krüger  Kurt H. Kjr 《第四纪科学杂志》2006,21(1):85-93

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Timing and significance of mid‐Holocene glacier advances in northern and central Iceland     

Martin P. Kirkbride  Andrew J. Dugmore 《第四纪科学杂志》2001,16(2):145-153

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Linking the North Atlantic to central Europe: a high‐resolution Holocene tephrochronological record from northern Germany     

Christel van den Bogaard  Hans‐Ulrich Schmincke 《第四纪科学杂志》2002,17(1):3-20

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Inundation extent as a key parameter for assessing the magnitude and return period of flooding events in southern Iceland     

Emmanuel Pagneux  Guðrún Gísladóttir  Árni Snorrason 《水文科学杂志》2013,58(5):704-716

Abstract

River flow conditions in many watersheds of Iceland are particularly disturbed during winter by the formation, drifting and accumulation of river ice, whose impact on water encroachment and extent of inundations is not reflected in the discharge records. It is therefore necessary to use river discharge with great caution when assessing the magnitude of past inundations in Iceland, and to give attention to other flood magnitude parameters. A GIS-based methodology is presented that focuses on inundation extent as an alternative parameter for the assessment and ranking of the magnitude of past flooding events in the Ölfusá-Hvítá basin, known as one of the most dangerous flood-prone river complexes in Iceland. Relying ultimately on a macro-scale grid, the method enabled the reconstruction of the extent of inundations, the delineation of the flood plain, and, finally, some estimation of the likelihood of flooding of exposed areas that include marine submergences and river floods for both open water and ice conditions.

Citation Pagneux, E., Gísladóttir, G. & Snorrason, Á. (2010) Inundation extent as a key parameter for assessing the magnitude and return period of flooding events in southern Iceland. Hydrol. Sci. J. 55(5), 704–716.  相似文献   

A runoff map based on numerically simulated precipitation and a projection of future runoff in Iceland / Une carte d'écoulement basée sur la précipitation numériquement simulée et un scénario du futur écoulement en Islande     

《水文科学杂志》2013,58(1):100-111

Abstract

The runoff of Iceland has been evaluated for the period 1961–1990, and changes in runoff from then to the period 2071–2100 predicted according to a future projection of climate change. The hydrological model WASIM-ETH was used, with meteorological data from the PSU/NCAR MM5 numerical weather model. The evaluation of the effects of climate change on water resources was based on a future climate simulation from the HIRHAM regional climate model with boundary conditions from the HadAM3H global climate model using A2 and B2 emissions scenarios. Future runoff was shown to become much higher in 2071–2100 compared to 1961–1990, predominantly due to increased glacial melt caused by increased temperature. Furthermore, changes in runoff seasonality would be substantial. Thus, according to this projection there could be great changes in hydropower production potential associated with climate change in Iceland.  相似文献