the 137cs technique applied to steep mediterranean slopes part i the effects of lithology slope morphology and land use concentrations in the soil of anthropogenic and natural radionuclides have been investigated in order to assess the applicability of the cs 137 technique in an area of typical mediterranean steep slopes this technique can be used to estimate net soil redistribution rates but its potential in areas with shallow and stony soils on hard rock lithology have not been evaluated so far in this research the validity of using this technique in stony shallow soils at very steep slopes is discussed together with the relations between radionuclide concentrations and other soil properties lithology slope morphology and land use in a mediterranean environment both natural potassium 40 4 k uranium 238 u 238 thorium 232 th 212 and anthropogenic caesium 137 cs 137 radionuclides have been determined in samples taken along slope transects on uncultivated serpentinite soils and cultivated gneiss soils in addition to the radionuclide concentrations parameters such as slope position slope angle aspect soil depth surface stone cover moss litter vegetation cover soil crust stone content and bulk density have been quantified all the natural radionuclides k 40 u 238 th 232 show significantly higher concentrations in the gneiss than in the serpentinite soils opposed to the cs 137 concentration which is found significantly higher in the serpentinite soils probably because of the difference in clay mineralogy the exponential decreasing depth distribution of cs 137 and its homogeneous spatial distribution emphasise the applicability of the cs 137 technique in this ecosystem lithology determines the concentration of natural and anthropogenic radionuclides land use determines the relations between cs 137 concentration inventory and some soil characteristics higher cs 137 concentration and inventory are associated with higher percentages of vegetation cover higher percentage of stones in the soil and higher values of soil bulk density in cultivated gneiss soils slope morphology and land use influence the soil redistribution at slope scale the gneiss slopes show a zonation of four to five areas of differential erosion accumulation processes corresponding with more regular slopes and soil redistribution due to water erosion and to tillage translocation and erosion the serpentinites as an example of a more unstable slope type show more erosion areas with less accumulation downslope and soil redistribution due to water erosion c 2003 elsevier b v all rights reserved

the effects of fire and water repellency on infiltration and runoff under mediterranean type forest abstract an investigation is being made into the relationship between forest fire and hillslope hydrology in the selva region of catalonia over a three year period at sites with a known fire history the major sites are on granite granodiorite or on sediments derived from these rocks at locations between santa christina d aro and santa coloma de farnes it appears that there is a general relationship between the type of organic profile found in a forest and the impact of fire in terms of loss of organic matter soil erosion hillslope hydrology and on the regeneration of the forest this paper summarises the results of about 150 rainfall simulation experiments and presents an overview of work carried out so far a major conclusion is that runoff processes are discontinuous and spatially structured due mainly to the effects of water repellency as a result of surface properties macropores hydrophobic behaviour and swelling four types of infiltration curve can be recognised at many locations infiltration increases with time during the early part of an experiment reaches a maximum value after about 30 minutes therupon subsequently decreasing this type of relationship can not be modelled with standard infiltration equations illustrations are given of sections through both burnt and unburnt soils to show how the hydrophobic effect influences water penetration it can be seen that infiltration patterns are similar for both burnt and unburnt soils and that micropores filled with organic matter are very important in conducting water through a water repellent surface layer the hydrophobic layer traps water in the bc horizon and prevents evaporation and loss by upwards capillary movement although the hydrophobic effects mean that small areas sometimes have a high runoff coefficient on larger areas there are many macropores and shrubs beneath which the soil is permeable and these trap runoff generated on the water repellent areas the main effect of fire is to illiminate the storage of water in the organic horizons several cm at first infiltration rates remain high but later these decrease as there is a reduction in porosity the sites having a moder type profile have better water retention properties more organic matter that survives the fire and a faster rate of vegetation recovery sites with a mor type profile can be degraded and erode if they are subject to disturbance the study provides another example of how on seemingly uniform slopes hydrological processes are structured by interactions with vegetation the patterns produced by these interactions survive the effects of fire

salt marsh sea level indicators and transfer function development for the magdalen islands in the gulf of st lawrence canada abstract late holocene salt marsh sediments allow the reconstruction of pre industrial relative sea level changes typically reconstructions are derived by quantifying a relationship between contemporary proxies and elevation which is then applied to down core fossil assemblages via a transfer function common sea level indicating proxies are salt marsh foraminifera and diatoms however testate amoebae represent an alternative complementary proxy with current sea level research increasingly invoking multi decadal timescale processes such as ocean current strength or wind stress to explain relative sea level changes there is a need for increased vertical precision in reconstructions this paper presents new surface assemblages of salt marsh foraminifera and testate amoebae with respect to elevation from two coastal locations in the magdalen islands in the gulf of st lawrence eastern canada we analyse the suitability of each proxy for reconstructing sea level using multivariate statistics ordination and regression modelling testate amoebae are found in greater abundance and diversity than foraminifera and their assemblage variations can be better accounted for by changes in elevation the contemporary training sets from the magdalen islands were able to predict marsh surface elevations viz sea level to precisions of 0 08 m and 0 12 m for testate amoebae and foraminifera respectively there were no benefits from combining the two proxies into a unified training set it was possible to improve the performance of the foraminifera based transfer function by incorporating a second dataset from newfoundland which served to increase the range of the sampled environment and improve the correlation coefficient between sample elevations and model predictions in accordance with existing literature we find transfer function performance to be better at locations with smaller tidal ranges

relative sea level response to little ice age ice mass change in south central alaska reconciling model predictions and geological evidence abstract integration of geological data and glacio isostatic adjustment gia modelling shows that it is possible to decouple complex mechanisms of relative sea level rsl change in a tectonically active glacial environment we model a simplest solution in which rsl changes in upper cook inlet alaska are a combination of the interplay of tectonic and isostatic processes driven by the unique rheology of this tectonically active location we calculate interseismic uplift during latter part of the penultimate earthquake cycle to vary from 0 3 to 0 7 mm yr diatom based reconstructions of rsl from tidal marsh sediment sequences coupled with detailed age models from ad 1400 to the ad 1964 great earthquake show deviations from a purely tectonically driven model of regional rsl glacial isostatic modelling constrained by gps data predicts up to 70 cm sea level change due to mountain glacier mass balance changes during the little ice age misfits between the gia model predictions and rsl reconstructions in the 19th and 20th century highlight that the tidal marshes of upper cook inlet potentially record a hemispheric wide acceleration in sea level and that other more complex earth process combinations may contribute to regional rsl change

multiproxy isotope constraints on ocean compositional changes across the late neoproterozoic ghaub glaciation otavi group namibia abstract chromium isotopes are powerful in recording redox fluctuations in marine environments potentially tracing past atmospheric oxygenation and continental weathering we present 53 cr signals with 87 sr 86 sr 13 c and 18 o and element abundances in carbonates of two shallow marine successions of the otavi group namibia stretching over four stages from preglacial setting to retreat of the late neoproterozoic ghaub glaciation 635 ma the fluctuating but generally heavy 53 cr signals indicate oxygenated shallow seawater prior to the glaciation stage 1 sustained high 13 c carb signatures at that time suggest organic matter formed a greater proportion of buried carbon which implies a net increase in oxidant flux to the surface the 18 o signals fluctuate with a tendency towards lighter values approaching the ghaub fm correlating 53 cr and 13 c carb values indicate disruptions affecting the carbon cycle and oxygen availability stage 2 prior to the ghaub diamictite a sequence of 87 sr 86 sr in the range typical of late neoproterozoic seawater occurs with high sr concentrations low mn sr and low mg ca enhanced detrital input after the ghaub glaciation stage 3 indicates elevated weathering rates likely accompanied by enhanced nutrient influx the 53 cr 13 c carb patterns are resolved in a two step recovery towards the late glacial aftermath stage 4 which is characterized by values similar to those of the early preglacial interval there a sequence of postglacial limestones also records typical late neoproterozoic seawater 87 sr 86 sr ratios the carbonate 53 cr signatures at the base of the postglacial sequence are characterized by values even below the range of bulk silicate earth bse we hypothesize that this is due to i redox cycling of cr in seawater e g by partial reduction of cr vi during microbial mediated cap dolostone deposition and or at the redox boundary of redox stratified seawater and or due to ii increased contribution of negatively fractionated cr associated with an enhanced input of detrital derived cr from postglacial weathering and or subaqueous hydrothermal influx previously it was demonstrated that carbonate 53 cr signatures trace changes in continental weathering and provide valuable indication of fluctuating seawater redox conditions prior to and after one of the major syn marinoan glaciations furthermore changes in 53 cr values might scale with shifts in bioproductivity

relative sea level change in west greenland during the last millennium relative sea level rsl data provide important long term century to millennial scale constraints on ice load history in greenland in this paper we present the results of a litho bio and chronostratigraphic study designed to reconstruct rsl during the last millennium from salt marsh deposits recovered from a field site near to the town of sisimiut west greenland the stratigraphy at three marshes typically records an upwards transition from freshwater to salt marsh deposits we use a quantitative transfer function and subjective model to reconstruct palaeomarsh elevation and changes in mean tide level mtl from 16 sediment profiles from these marshes these palaeomarsh elevations are placed in a chronological framework established by 18 radiocarbon dated index points both models yield similar results and show mtl rose from 0 60 0 20 m at c 600 cal a bp to reach 0 10 0 20 m at c 400 cal a bp after this time mtl remained close to present 0 20 m until the present day although low sedimentation rates limit the resolution of our reconstructions during this interval the initial rise in rsl can be explained by the dominance of non greenland processes notably the collapse of the laurentide forebulge over local greenland solid earth uplift caused by postglacial ice unloading this is despite some reloading of the crust that occurred during the neoglacial expansion of the greenland ice sheet in this part of west greenland the slow down in rsl at 400 cal a bp does not record either a change in the rate of laurentide forebulge collapse or a change in eustatic sea level we argue instead that this slow down records the effects of a sustained reduction in local greenland ice mass that persists over most of the past 400 years the latter interval is widely acknowledged as a period of generally cooler than present conditions associated with the later stages of the little ice age during this period field evidence suggests that in many areas the ice sheet had reached its maximum late holocene extent it is not obvious at this stage how to reconcile an expanding ice sheet with a reduction in ice load during this interval although we hypothesise it could reflect one or more of i a change in ice sheet dynamics ii reduced mass accumulation caused by cold and dry conditions and iii a lagged response to earlier periods of climate warming

rock fragments in top soils significance and processes this introductory paper reviews various aspects of rock fragments in top soils such information is required for various reasons and in particular for predicting the impact of climatic or landuse changes on the response of these soils particular attention is paid to the definition and measurement of rock fragment content in top soils the density of soils containing rock fragments the spatial distribution and movement of rock fragments in top soils the effects of rock fragments on some key hydrological processes thermal properties of top soils physical soil degradation soil erosion and soil productivity

algae influence the hydrophysical parameters of a sandy soil abstract article history received 2 august 2011received in revised form 31 january 2012accepted 3 february 2012available online xxxxkeywords algaebiological soil crustsoil water repellencysand dunesorptivityhydraulic conductivity biological soil crusts have a major effect on water ow in soils two study sites located at a pine forest gladecovered with a biologicalsoil crust formed the basis of our study the sand soil atthe surface glade soil wascompared to a control soil pure sand with limited impact of vegetation or organic matter occurring at50 cm depth beneath a glade area to assess the in uence ofalgae in the biological soil crust on the propertiesof pure sand a coccal green alga choricystis minor lamentous green alga klebsormidium subtile and stra menopile alga tribonema minus were isolated from the top layer of glade soil and grown in the lab in petridishes on sterile pure sand as monoalgal and bialgal c minor and k subtile crusts for 3 5 7 9 11 13 15 17 19 and 21 days atthe end ofeach growth stage the hydrophysicalparametersof crusted sand were estimat ed after drying at 50 c for 15 h equivalent to a 3 day hot spell and compared to the parameters of puresand the hydrophysical parameters were substantially different between the two surfaces the glade soilhad an index of water repellency about 18 times that of pure sand and the persistence of water repellencyalmost 54 times that of pure sand both sorptivity and hydraulic conductivity in the glade soil were about7 those of the pure sand respectively the growth of arti cial algal crusts characterized by an increase inorganic carbon content from 0 16 to 0 33 resulted in an increase in water drop penetration time of thedried crusts up to 14 times that of the pure sand and a decrease in the water sorptivity of the dried crustsup to 10 that of the pure sand whereas k subtile crusts both monoalgal and bialgal with c minor hadup to a 9 decrease in hydraulic conductivity compared to pure sand there was no impact of monoalgalc minor and t minus crusts on hydraulic conductivity k subtile was possibly limited to surface growth whereas c minor and t minus penetrated to depth consequently k subtile may have clogged the toppores more effectively than the other two strains the water repellency cessation time increased with anincrease in water drop penetration time for all the dried monoalgal and bialgal crusts used in this study agreater impact of k subtile on the shifts in hydraulic behaviour could in uence water capture and storage potentially decreasing evaporation during dry periods but enhancing overland ow diminishing leachingduring wet periods 2012 elsevier b v all rights reserved

space geodesy constrains ice age terminal deglaciation the global ice 6g_c vm5a model a new model of the last deglaciation event of the late quaternary ice age is here described and denoted as ice 6g c vm5a it differs from previously published models in this sequence in that it has been explicitly refined by applying all of the available global positioning system gps measurements of vertical motion of the crust that may be brought to bear to constrain the thickness of local ice cover as well as the timing of its removal additional space geodetic constraints have also been applied to specify the reference frame within which the gps data are described the focus of the paper is upon the three main regions of last glacial maximum ice cover namely north america northwestern europe eurasia and antarctica although greenland and the british isles will also be included if peripherally in the discussion in each of the three major regions the model predictions of the time rate of change of the gravitational field are also compared to that being measured by the gravity recovery and climate experiment satellites as an independent means of verifying the improvement of the model achieved by applying the gps constraints several aspects of the global characteristics of this new model are also discussed including the nature of relative sea level history predictions at far field locations in particular the caribbean island of barbados from which especially high quality records of postglacial sea level change are available but which records were not employed in the development of the model although ice 6g c vm5a is a significant improvement insofar as the most recently available gps observations are concerned comparison of model predictions with such far field relative sea level histories enables us to identify a series of additional improvements that should follow from a further stage of model iteration

relative sea level change in connecticut usa during the last 2200 yrs we produced a relative sea level rsl reconstruction from connecticut usa spanning the last 2200 yrs that is free from the influence of sediment compaction the reconstruction used a suite of vertically and laterally ordered sediment samples 2 cm above bedrock that were collected by excavating a trench along an evenly sloped bedrock surface paleomarsh elevation was reconstructed using a regional scale transfer function trained on the modern distribution of foraminifera on long island sound salt marshes and supported by bulk sediment 13c measurements the history of sediment accumulation was estimated using an age elevation model constrained by radiocarbon dates and recognition of pollution horizons of known age the rsl reconstruction was combined with regional tide gauge measurements spanning the last 150 yrs before being quantitatively analyzed using an error in variables integrated gaussian process model to identify sea level trends with formal and appropriate treatment of uncertainty and the temporal distribution of data rsl rise was stable 1 mm yr from 200 bce to 1000 ce slowed to a minimum rate of rise 0 41 mm yr at 1400 ce and then accelerated continuously to reach a current rate of 3 2 mm yr which is the fastest century scale rate of the last 2200 yrs change point analysis identified that modern rates of rise in connecticut began at 1850 1886 ce this timing is synchronous with changes recorded at other sites on the u s atlantic coast and is likely the local expression of a global sea level change earlier sea level trends show coherence north of cape hatteras that are contrasted with southern sites this pattern may represent centennial scale variability in the position and or strength of the gulf stream comparison of the new record to three existing and reanalyzed rsl reconstructions from the same site developed using sediment cores indicates that compaction is unlikely to significantly distort rsl reconstructions produced from shallow 2 3 m thick sequences of salt marsh peat

a sensitive high resolution record of late holocene climatic change from a raised bog in northern england proxy climatic data in the form of plant macrofossils have been analysed from a 5 m core from bolton fell moss cumbria uk detailed analysis of peat from the upper 50 cm of this core is used to demonstrate a strong correlation between changes in the relative proportion of taxa and known climatic changes over the last 1000 years the record of changes in bog vegetation contained within the peat profile is used to reconstruct changes in bog surface wetness for the latter half of the holocene as bog surface wetness is directly controlled by the prevailing climatic conditions this reconstruction can be viewed as a proxy climate record twelve radiocarbon age estimates on the 5m core suggest that between 50 and 500 cm peat accumulated at a relatively constant rate of 12 4 yr cm 1 the regular sampling intervals thus provide a time series of past bog surface wetness spectral analyses of this series indicates that wetness changes are cyclic with a ca 800 year periodicity

holocene relative sea level fluctuations in the st lawrence estuary quebec canada abstract between 7000 and 6000 yr b p relative sea level was as much as 5 m lower than today in the st lawrence estuary quebec a small transgression laurentian transgression occurred between 5800 and 4400 yr b p which resulted in the construction of an 8 to 10 m terrace about 3000 yr b p relative sea level was similar to present and then a stillstand or a slight rise occurred during which a cliff micmac cliff was cut into the emerged terrace during a subsequent lowering of relative sea level coastal emergence a low aggradational terrace mitis terrace was built between 2300 and 1500 yr b p at the base of the micmac cliff a new emergence curve for the south shore of the st lawrence estuary showing a mid holocene high stand of relative sea level is therefore proposed

rock fragments and soil hydrological processes significance and progress abstract in this review we explore the significance of rock fragments in studies of soil hydrological processes because according to research the effects of rock fragments on soil hydrological processes are inconsistent positive negative rock fragments play a critical role in the biosphere as the primary filter for water and solutions containing contaminants and heavy metals rock fragments have a complex influence on soil hydrological processes e g soil erosion runoff generation water infiltration solute transport and water flow and are highly relevant in a typical system in the soil plant atmosphere continuum cracks related to rock fragments provide preferential flow paths through which pollutants are transported into groundwater in this paper the published literature is reviewed concentrating on rock fragments and their effects on soil hydrological processes systematic studies and examples illustrate the effects of rock fragments architecture i e coverage content size position spatial heterogeneity morphology weathering and topography on soil hydrological processes methods and models applied to evaluate the effects of rock fragments on soil hydrological processes are examined in detail we conclude that the relationship between rock fragments and soil hydrological processes is complicated and requires more international research efforts this review concludes with a discussion of perspectives on areas of research that can improve understanding of the effects of rock fragments on soil hydrological processes with insights and suggestions also being provided regarding potential research trends requirements and solutions

effect of forest floor characteristics on water repellency infiltration runoff and soil loss in andisols of tenerife canary islands spain abstract given its singular properties and location forest floor litter duff is a key factor in hydrological processes water infiltration research was carried out for the present study in andisols at ten sites six of which had coverings of pine forest and four of rainforest rainfall simulations were conducted on gentle moderately steep and steep slopes 10 30 and 50 to determine infiltration runoff and soil loss as a function of the forest floor characteristics the duff on the pine forest soils consists of moderately porous extremely hydrophobic and consistent semi decomposed organic material which is rich in fungi hyphae the duff on the rainforest soils is formed by highly porous loose semi decomposed organic material the study results highlight the influential role played by the forest floor in infiltration and runoff infiltration barely reaches 20 mm h 1 in pine forest compared to 50 mm h 1 in rainforest as a consequence the pine forest runoff is twice that recorded in rainforest sites the wetting front on gentle and moderately steep slopes evidences the influence of the duff on infiltration in pine forest most of the rainwater remains in the duff and infiltration depends little therefore on the underlying mineral soil properties in rainforest the wetting front extends below the duff and the well developed soil structure is a major factor in water infiltration the differences noted in the two parameters are not found on the steep slopes no soil loss differences are observed between the two vegetation covers and forest floors despite the greater runoff in pine forest the results demonstrate the protective effect of the organic covering and how the stability of the andisols helps combat water erosion processes

regional differences of relative sea level changes in the northwest atlantic historical trends and future projections 1 mean sea level is one of the most important indicators for climate variability and change here we use tide gauge data and satellite measurements to examine recent trends in the mean relative sea level rsl in the northwest atlantic we then combine model output and satellite observations to provide sea level projections in the 21st century the mean rsl trend based on historical tide gauge data shows large regional variations from 2 to 4 mm yr above the global mean rsl rise rate in the southeast to 2 mm yr in the northwest along east canada this spatial difference can to a large degree be attributed to that in the vertical land motion measured by the global positioning system gps the combination of altimeter measured sea level change with the gps data can approximately account for tide gauge measurements at most stations over 1993 2011 when the gps data are used the projected mean rsl rise between 1980 1999 and 2090 2099 ranges from 38 to 63 cm along the scotia fundy and newfoundland coasts and smaller along labrador the northern gulf of st lawrence and the st lawrence estuary in spite of considerable uncertainties the ocean steric and dynamical effect is the dominant contributor 35 70 cm to the rsl rise along the canadian east coast the land ice glaciers and ice sheets melt contributes to the rsl rise by 10 15 cm except at nain where it is negligible the effect of the vertical land uplift is large 40 50 cm at nain sept iles and rimouski significantly reducing the magnitude of the rsl rise

patterns of rock fragment cover generated by tillage erosion abstract intensively cultivated areas in the upper part of the guadalentin catchment southeast spain show a systematic spatial pattern of surface rock fragment cover rc the objective of this paper is to quantify and to explain this spatial rock fragment cover pattern therefore a map of an intensively cultivated area of 5 km2 was digitised and for each pixel total topographic curvature was calculated next rock fragment cover was determined photographically at 35 sites with a range of total slope curvatures a linear relation between total curvature and rock fragment cover was found except for narrow concavities it was hypothesised that this pattern can be explained by a significant net downslope movement of rock fragments and fine earth by tillage the displacement distances of rock fragments by tillage with a duckfoot chisel were measured by monitoring the displacement of tracers painted rock fragments and aluminium cubes on 5 sites having different slopes the rare of tillage erosion for one tillage pass with a duckfoot chisel expressed by the diffusion constant k equals 282 kg m for up and downslope tillage and only 139 kg m for contour tillage nomograms indicate that mean denudation rates in almond groves due to tillage erosion 3 to 5 tillage passes per year can easily amount to 1 5 2 6 mm year for contour tillage and up to 3 6 5 9 mm year for up and downslope tillage for a field 50 m long and having a slope of 20 these figures are at least one order of magnitude larger than reported denudation rates caused by water erosion in similar environments hence tillage erosion contributes significantly to land degradation the downslope soil flux induced by tillage not only causes considerable denudation on topographic convexities hill tops and spurs and upper field boundaries but also an important sediment accumulation in topographic concavities hollows and valley bottoms and at lower field boundaries kinetic sieving i e the upward migration of rock fragments by the tines of the duckfoot chisel also concentrates the largest rock fragments in the topsoil in such a way that a rock fragment mulch develops in narrow valleys and at the foot of the slopes these results clearly indicate that tillage erosion is the main process responsible for the observed rock fragment cover pattern in the study area since the study area is representative for many parts of southern spain where almond groves have expanded since 1970 the results have a wider application they show to what extent intensive tillage of steep slopes has contributed to the increase in soil degradation to changes in hillslope morphology i e strong denudation of convexities development of lynchets and rapid infilling of narrow valley bottoms and to the development of rock fragment cover patterns which control the spatial variability of the hydrological and water erosion response within such landscapes

can terra rossa become water repellent by burning a laboratory approach abstract fire usually induces water repellency wr in soils reduction in infiltration rates increase of runoff and erosion are some of the consequences of wr in fire affected soils most forest soils can develop wr by burning however some previous observations in burned terra rossa soils have shown little changes in wr laboratory controlled experiments have been done with samples of terra rossa from 14 different sites the objectives are to confirm whether the observed is a common behaviour of terra rossa and to explore the factors controlling the wettability of this soil type after burning samples from the upper 2 5 cm of terra rossa were collected from 12 forest sites of the alicante province spain and from 2 sites in the mt carmel haifa israel with similar environmental conditions laboratory burning of samples at 250 c 300 c and 350 c was performed with and without the addition of litter of pinus halepensis the results confirm that all soils have a very low susceptibility to become water repellent by burning without the addition of litter wr was not detected in any soil sample at any temperature of burning with the addition of litter wr was present only in six of the soils after some of the heating treatments although all soils had enough soil organic matter som to develop wr by heating the ratio between som and clay content was considerably lower compared to other types of forest soils of the region in which wr has been found after forest fires this could explain in part the lower susceptibility of terra rossa to become water repellent by burning since as some authors have indicated fine textured soils are less prone to develop soil wr due to their high specific surface area from mineralogical analysis of the clay fraction we found that the dominant clay types in the studied terra rossa were kaolinite and illite with the exception of one soil where ca montmorillonite content is higher than kaolinite and illite ca montmorillonite was present in only three of the soils comparing the soil properties between the group of terra rossa that in no case become water repellent wettables with the group that in some cases developed wr potentially water repellents some differences were found the kaolinite content is higher in the wettables group p vs kaolinite contents the kaolinite content being the main factor contributing to this separation these results are in agreement with those obtained in experiments with clay additions to water repellent soils in order to reduce the wr and also with some studies which found that kaolinite is one of the most effective clay minerals for this purpose

testing the robustness of semi empirical sea level projections we determine the parameters of the semi empirical link between global temperature and global sea level in a wide variety of ways using different equations different data sets for temperature and sea level as well as different statistical techniques we then compare projections of all these different model versions over 30 for a moderate global warming scenario for the period 2000 2100 we find the projections are robust and are mostly within 20 of that obtained with the method of vermeer and rahmstorf proc natl acad sci usa 106 21527 21532 2009 namely 1 m for the given warming of 1 8 c lower projections are obtained only if the correction for reservoir storage is ignored and or the sea level data set of church and white surv geophys 2011 is used however the latter provides an estimate of the base temperature t 0 that conflicts with the constraints from three other data sets in particular with proxy data showing stable sea level over the period 1400 1800 our new best estimate model accounting also for groundwater pumping is very close to the model of vermeer and rahmstorf proc natl acad sci usa 106 21527 21532 2009

fire and aspect induced differences on the erodibility and hydrology of soils at la costera valencia southeast spain this paper presents measurements of soil aggregation parameters and rainfall simulation experiments from areas of mediterranean scrubland vegetation in la costera district in the southern part of valencia province spain data were obtained using a portable rainfall simulator and from laboratory studies of aggregate stability using the water drop test and ultrasonic dispersion methods three locations were chosen to enable the influences of aspect and the post fire recovery time of the vegetation on soil erosion and hydrology to be investigated the slopes studied were a a north facing slope burnt ten years before the experiment b a south facing slope burnt at the same time and c a north facing slope burnt two years before the experiment similar to slope a in terms of its basic characteristics the experiments demonstrate the importance of both wildfires and aspect on hydrological and erosional soil surface processes the north facing slope at la costera slope a has a higher aggregate stability than the corresponding south facing slope slope b the recently burnt north facing slope c is intermediate in terms of aggregation but has the most erodible soils because of the lower infiltration rates and the low vegetation and litter cover nevertheless for the slopes burnt ten years previously the south facing slope is more erodible than the north facing one the results suggest that the forest fire ten years ago did not produce a persistent degradation of the ecosystem only higher soil and water losses during the first years following the fire a southern aspect where vegetation recovery rates are slower and the hydraulic stress is higher favours the development of soils with a relatively low aggregate stability

fire severity and surface rock fragments cause patchy distribution of soil water repellency and infiltration rates after burning although fire induced soil water repellency swr and its effects on soil hydrology and geomorphology have been studied in detail very few studies have considered the effect of rock fragments resting on the soil surface or partly embedded in soil in this research we have studied the effect of rock fragments on the strength and spatial distribution of fire induced swr at different fire severities a fire affected area was selected for this experiment and classified into different zones according to fire severity unburned low moderate and high and rock fragment cover low 60 during 7 days after fire swr and infiltration rates were assessed in the soil surface covered by individual rock fragments and in the midpoint between two adjacent rock fragments with maximum spacing of 20 cm swr increased with fire severity rock fragments resting on the soil surface increased the heterogeneity of the spatial distribution of fire induced swr swr increased significantly with rock fragment cover in bare areas under moderate and high fire severity but quantitatively important changes were only observed under high fire severity in areas with a low rock fragment cover water repellency from soil surfaces covered by rock fragments increased relative to bare soil surfaces with increasing swr in areas with a high rock fragment cover swr increased significantly from non covered to covered soil surfaces only after low severity burning rock fragment cover did not affect infiltration rates although it decreased significantly in soil surfaces after high severity burning in areas under low and high rock fragment cover copyright 2013 john wiley sons ltd

variation in water content and wetting patterns in dutch water repellent peaty clay and clayey peat soils abstract the variation in water content of grass covered peaty clay and clayey peat soils was studied at six sites in the netherlands the topsoils were water repellent during dry spells when the topsoils were dry they could only absorb water with difficulty which is illustrated by wetting rate measurements precipitation could flow rapidly through shrinkage cracks towards the subsoil bypassing the matrix of the peat however the measurements revealed that preferential flow was not limited to macropore flow irregular fingerlike wetting patterns were also formed in the soil matrix due to these typical wetting patterns soil water content varied over short distances at all sites at all sampling dates