Small-scale Differences Research Articles

Ländliche räume in Lateinamerika: globalisierung und lokale reaktionen

Die ländlichen Räume in Südamerika unterliegen in den letzten Jahrzehnten zunehmenden Globalisierungseinfl üssen, die zu einem tiefgreifenden Strukturwandel geführt haben, der bis heute im Gange ist. Dabei sind nicht nur Veränderungen in den wirtschaftlichen Bereichen zu beobachten. Auch sozio-kulturelle, politische und ökologische Sphären werden restrukturiert. Die damit verbundenen Prozesse erfassen somit praktisch alle Lebensbereiche der ländlichen Bevölkerung, so dass Akteure auf lokaler und regionaler Ebene gezwungen sind, sich neu zu positionieren. Die Reaktionen reichen dabei von der aktiven Anpassung an und Integration in globalisierte Wirkungszusammenhänge bis hin zum Rückzug aus den übergeordneten Kontexten und der Erschließung neuer Handlungsoptionen auf lokaler Ebene. Diese vielfältigen Prozesse in den ländlichen Räumen Südamerikas lassen sich in verschiedene Entwicklungsdynamiken diff erenzieren. Die agro-industrielle Entwicklungsdynamik ist charakterisiert durch eine Landwirtschaft,
 in der standardisierte Massenprodukte dominieren, die von Billiglohnarbeitern hergestellt werden und für den Massenkonsum vor allem auf globaler Ebene bestimmt sind. In der postproduktivistischen
 Entwicklungsdynamik fungiert der ländliche Raum hingegen als Konsumraum einer städtischen oder/und globalen Elite, die ihre Freizeit dort gestalten will und ökologische Ausgleichsfl ächen für die „eigene“ degradierte Umwelt benötigt. In der als alternativ bezeichneten
 Entwicklungsdynamik schließlich dominieren eindeutig die lokal-regionalen Akteure, deren
 Hauptaugenmerk auf der Überlebenssicherung der lokalen Bevölkerung, auf der Sicherung der
 ökologischen Ressourcen und auf der Erhaltung der lokalen Gemeinschaft liegt. Diese
 Entwicklungsdynamiken überlagern sich zeitlich und räumlich. Die vielschichtigen kleinräumigen
 Diff erenzierungen sind verbunden mit einer entsprechenden Erweiterung der Funktionen der
 ländlichen Räume im lokalregionalen, nationalen und internationalen Kontext. Ländliche
 Entwicklungsplanung und die darin involvierten politischen Entscheidungsträger stehen damit vor
 neuartigen Herausforderungen, die neue Konzepte und Leitbilder verlangen.

Grassland structural heterogeneity in a savanna is driven more by productivity differences than by consumption differences between lawn and bunch grasses.

Savanna grasslands are characterized by high spatial heterogeneity in vegetation structure, aboveground biomass and nutritional quality, with high quality short-grass grazing lawns forming mosaics with patches of tall bunch grasses of lower quality. This heterogeneity can arise because of local differences in consumption, because of differences in productivity, or because both processes enforce each other (more production and consumption). However, the relative importance of both processes in maintaining mosaics of lawn and bunch grassland types has not been measured. Also their interplay been not been assessed across landscape gradients. In a South African savanna, we, therefore, measured the seasonal changes in primary production, nutritional quality and herbivore consumption (amount and percentage) of grazing lawns and adjacent bunch grass patches across a rainfall gradient. We found both higher amounts of primary production and, to a smaller extent, consumption for bunch grass patches. In addition, for bunch grasses primary production increased towards higher rainfall while foliar nitrogen concentrations decreased. Foliar nitrogen concentrations of lawn grasses decreased much less with increasing rainfall. Consequently, large herbivores targeted the biomass produced on grazing lawns with on average 75 % of the produced biomass consumed. We conclude that heterogeneity in vegetation structure in this savanna ecosystem is better explained by small-scale differences in productivity between lawn and bunch grass vegetation types than by local differences in consumption rates. Nevertheless, the high nutritional quality of grazing lawns is highly attractive and, therefore, important for the maintenance of the heterogeneity in species composition (i.e. grazing lawn maintenance).Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-016-3698-y) contains supplementary material, which is available to authorized users.

Visual analytics for text-based railway incident reports

The GB railways collect about 150,000 text-based records each year on potentially dangerous events and the numbers are on the increase in the Close Call System. The huge volume of text requires considerable human effort to its interpretation. This work focuses on visual text analysis techniques of Close Call records to extract safety lessons more quickly and efficiently. This paper treats basic steps for visual text analysis based on an evaluation test using a pre-constructed test set of 150 Close Call records for “Trespass”, “Slip/Trip hazards on site” and “Level crossing”. The results demonstrate that visual text analysis can be used to identify the risks in a small-scale test set but differences in language use by different cohorts of people interferes with straightforward risk identification in larger sets. This work paves the way to machine-assisted interpretation of text-based safety records which can speed up risk identification in a large corpus of text. It also demonstrates how new possibilities open up to develop interactive visualisations tools that allow data analysts to use text analysis techniques for risk analysis.

Radical Interpretation and the Problem of Asymmetry

Davidson holds that thinkers cannot employ radically different conceptual schemes, but he does not deny the (seemingly obvious) fact that small-scale conceptual divergences are possible. He defends the former claim against Quine by appealing to interpretivism, the idea that ascriptions of intensional states to a speaker do no more than systematically record facts about the speaker’s behavior. From interpretivism it follows that it is theoretically (though not practically) irrelevant which set of concepts an interpreter uses to state her theory of meaning. This is what allows Davidson to avoid conceptual relativism while accepting Quine’s thesis that behavioral evidence necessarily underdetermines assignments of meaning to speakers. However, as Davidson seems not to have realized, interpretivism also rules out the possibility of uncontroversial, small-scale conceptual differences. This fact, I argue, should lead us to reject interpretivism.

Variation in the composition of corals, fishes, sponges, echinoderms, ascidians, molluscs, foraminifera and macroalgae across a pronounced in-to-offshore environmental gradient in the Jakarta Bay–Thousand Islands coral reef complex

Substrate cover, water quality parameters and assemblages of corals, fishes, sponges, echinoderms, ascidians, molluscs, benthic foraminifera and macroalgae were sampled across a pronounced environmental gradient in the Jakarta Bay–Thousand Islands reef complex. Inshore sites mainly consisted of sand, rubble and turf algae with elevated temperature, dissolved oxygen, pH and chlorophyll concentrations and depauperate assemblages of all taxa. Live coral cover was very low inshore and mainly consisted of sparse massive coral heads and a few encrusting species. Faunal assemblages were more speciose and compositionally distinct mid- and offshore compared to inshore. There were, however, small-scale differences among taxa. Certain midshore sites, for example, housed assemblages resembling those typical of the inshore environment but this differed depending on the taxon. Substrate, water quality and spatial variables together explained from 31% (molluscs) to 72% (foraminifera) of the variation in composition. In general, satellite-derived parameters outperformed locally measured parameters.

Cheating the Locals: Invasive Mussels Steal and Benefit from the Cooling Effect of Indigenous Mussels.

The indigenous South African mussel Perna perna gapes during periods of aerial exposure to maintain aerobic respiration. This behaviour has no effect on the body temperatures of isolated individuals, but when surrounded by conspecifics, beneficial cooling effects of gaping emerge. It is uncertain, however, whether the presence of the invasive mussel Mytilus galloprovincialis limits the ability of P. perna for collective thermoregulation. We investigated whether varying densities of P. perna and M. galloprovincialis influences the thermal properties of both natural and artificial mussel beds during periods of emersion. Using infrared thermography, body temperatures of P. perna within mixed artificial beds were shown to increase faster and reach higher temperatures than individuals in conspecific beds, indicating that the presence of M. galloprovincialis limits the group cooling effects of gaping. In contrast, body temperatures of M. galloprovincialis within mixed artificial mussel beds increased slower and exhibited lower temperatures than for individuals in beds comprised entirely of M. galloprovincialis. Interestingly, differences in bed temperatures and heating rates were largely dependent on the size of mussels, with beds comprised of larger individuals experiencing less thermal stress irrespective of species composition. The small-scale patterns of thermal stress detected within manipulated beds were not observed within naturally occurring mixed mussel beds. We propose that small-scale differences in topography, size-structure, mussel bed size and the presence of organisms encrusting the mussel shells mask the effects of gaping behaviour within natural mussel beds. Nevertheless, the results from our manipulative experiment indicate that the invasive species M. galloprovincialis steals thermal properties as well as resources from the indigenous mussel P. perna. This may have significant implications for predicting how the co-existence of these two species may change as global temperatures continue to rise.

Origin of a boreal birch bog woodland and landscape development on a warm low mountain summit at the Carpathian–Pannonian interface

Hilly regions along the Western Carpathian–Pannonian border are phytogeographically important, but their vegetation history remains largely unknown. We analysed two peat cores of Late Glacial origin from a bog woodland in the Malé Karpaty Mts (SW Slovakia) using plant macrofossil, pollen, peat chemistry and charcoal analyses to trace local successional patterns, regional vegetation development and occurrence of rare species. The small distance between the two profiles situated within homogeneous vegetation enabled us to explore small-scale differences in local vegetation history. The sediment started to accumulate at the end of the Allerød (ca. 12950 cal. yr BP), when a shallow oligotrophic/mesotrophic lake with macrophytes developed. Open pine-birch forests dominated in the landscape. During the early Holocene, the lake was infilled, mire vegetation appeared and broad-leaved forests spread in the surroundings. Two fire events indicated by increases in number of macroscopic charcoal particles were recorded. The first one, which occurred at the end of the Late Glacial, was found only in one of the profiles, while the second one affected entire mire and probably caused a hiatus spanning the middle and late Holocene. Fagus started to spread no later than 5800 cal. yr BP. Open mire vegetation reappeared after the fire (ca. 400 cal. yr BP). During the 19th century, the mire was overgrown by a birch bog woodland. The two profiles showed basically the same successional patterns, but some local events and occurrences of rare species ( Potamogeton alpinus, Potamogeton praelongus, Scorpidium scorpioides and Pleurospermum austriacum) were traced only in one of them.

Group foraging decisions in nutritionally differentiated environments

Summary Foraging behaviour must be flexible enough to adapt to heterogeneities in the distribution and quality of food resources. Accurate models of optimal foraging behaviour should acknowledge the extent to which animals can detect and regulate their intake of food based on smaller scale differences in food types. In particular, consideration of macro‐nutrient distribution and how animals perceive this is limited in studies of optimal foraging, particularly in vertebrates and for animals that forage in groups. Here, we track shoals of eight mosquitofish as they forage in two environments that contain equal amounts of available energy but differ in their distribution of macro‐nutrients. We provide empirical evidence that fish will distribute themselves within an environment in relation to the distribution of specific macro‐nutrients. Also, fish make foraging decisions based on the macronutrient composition of patches, such that their durations on patches are longer when they have a higher concentration of protein and lower concentration of carbohydrate. The ratio of protein to carbohydrate does not affect the probability of a fish joining a patch, however, with low numbers of fish on the patch the probability of a fish leaving is greater per unit time step in the patches with a low protein to carbohydrate ratio than the patches with a high protein to carbohydrate ratio. This study confirms the importance of considering the macro‐nutrient composition of foods when considering the movement decisions of foraging groups and thus has important consequences for developing more accurate foraging models that take into account the distribution of macro‐nutrients in the environment. The results suggest the spatial distribution of nutrients on a landscape scale could influence grouping patterns and social interactions, thus affecting population dynamics.

Microhabitat Differences in the Benthic Substrata Affect Parasitism in a Pulmonate Snail Host, Helisoma anceps.

The microhabitats in which hosts live can potentially influence the ability and success of parasites in finding and infecting these hosts. The infection dynamics of both digenetic trematode parasites and a nematode parasite (Daubaylia potomaca) infecting a pulmonate snail, Helisoma anceps , were observed in a small North Carolina lake using 3 different classifications of substratum type based on percent coverage by leaves and debris. There were no differences in snail site occupancy or density between substratum types, but small-scale differences in microhabitat impacted parasite prevalence and intensity in their gastropod hosts. Snails inhabiting substrata covered in more leaf litter and debris had a lower prevalence and intensity of infection by all of the trematode species and life stages when compared to H. anceps inhabiting other substrata types, while only the intensity of infection was impacted in D. potomaca infections. These findings emphasize the importance of microhabitat, specifically its physical components, in influencing parasite infection in intermediate hosts and that small-scale differences may significantly affect the patterns of infection.

Co-occurrence of juvenile horseshoe crabs Tachypleus tridentatus and Carcinoscorpius rotundicauda in an estuarine bay, southwestern China

Spawning and nursery habitats are critical in the conservation of horseshoe crabs. We examined the abundance and distribution of juveniles of 2 species of horseshoe crabs, Tachypleus tridentatus and Carcinoscorpius rotundicauda, in a mangrove-vegetated estuary (Pearl Bay, Guangxi, China). Intertidal sampling and measurement of environmental variables were carried out in October 2014 at 4 sites spanning ~6.3 km from the inner to the outer bay. Both species were found at the 2 innermost mangrove sites but not at the outer 2 sites. Densities were higher than recorded in previous studies, 0.24 ind. m �2 for C. rotundicauda and 0.05 ind. m �2 for T. tridentatus. Although only 12 of the latter species were found, they appeared to be more abundant in more sea- ward, energetic environments in poorly sorted sediments, whereas C. rotundicauda occurred in sediments with higher silt-clay and organic carbon content, and aggregated at the mangrove forest edges. These small-scale distribution differences are consonant with the species' life histories, since only T. tridentatus migrates to the sea while C. rotundicaudata spends its entire life within or near mangrove habitats. International and national conservation strategies for these species should include further efforts to inventory critical habitats, such as Pearl Bay, in southeast Asia.

Die Innere Stadt als Wohnstandort der „jungen Alten“?

Is the inner city an attractive place for the “young elderly” to live? During decades suburbanization was the dominant pattern of city development in Germany. However, since the 2000s an increasing attraction of urban living and the trend of re-urbanization are discussed in research as well as in public. Due to an increasing average age and life expectancy of the population as a main sub-process of demographic change in Germany, the question arises whether the inner city as a residential area also becomes more attractive for the elderly. Especially “young elderly” people (ca. 50–70 years old) are getting into focus. Because of a transitional phase of their lives, they might show a greater willingness to change the residential location to adapt to their new needs.
 In order to analyze the attractiveness of the inner city as a residential area for the “young elderly”, residential location decisions, which were realized between 2010 and 2012, were investigated using the city of Bonn as an example. The results of a survey and in-depth interviews show that the inner city cannot be considered as a homogeneous space, but that small-scale differences in the attractiveness as a residential area exist. In summary, the “young elderly” prefer the fringe of the inner city while the city center is important for their shopping and leisure activities, but not as attractive for them to live. However, also within the fringe of the inner city more and less attractive residential areas can be identified corresponding to lifestyle and income of the “young elderly”.

Between‐Event Variance for Large Repeating Earthquakes

We estimate the variance in ground motions related to repeated large earthquakes occurring on the same fault segment with similar magnitudes. We find eight earthquake pairs for which suitable strong‐motion records exist. Two are crustal strike‐slip earthquakes from California and six are subduction zone earthquakes from Japan. We consider only large earthquakes and deal with frequencies greater than the earthquake corner frequency, so the variability that is considered here is related to smaller scale differences in the rupture process, particularly on the part of the fault nearest the station. We find that the variance of the 5% damped spectral accelerations of these pairs, termed ![Graphic][1] , averages to about 45% and 80% of τ 2 for the crustal and subduction zone earthquakes, respectively, in which τ 2 is the contribution of source variability to the total variability of ground motion estimated by some recent ground‐motion prediction equations. We suggest that ![Graphic][2] is lower than τ 2, for the frequencies at which ![Graphic][3] is estimated, because it depends primarily on only local physical properties of a fault that are the same in repeated earthquakes. We therefore suggest that at sites where the hazard is controlled by a single rerupturing source, one could potentially use a between‐event variance that is smaller than τ 2 in seismic‐hazard calculations. Thus, these results may help to resolve the inconsistencies that are now present between the national hazard maps and some precariously balanced rocks in southern California. [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif [3]: /embed/inline-graphic-3.gif

Experimental evidence for convergent evolution of maternal care heuristics in industrialized and small-scale populations.

Maternal care decision rules should evolve responsiveness to factors impinging on the fitness pay-offs of care. Because the caretaking environments common in industrialized and small-scale societies vary in predictable ways, we hypothesize that heuristics guiding maternal behaviour will also differ between these two types of populations. We used a factorial vignette experiment to elicit third-party judgements about likely caretaking decisions of a hypothetical mother and her child when various fitness-relevant factors (maternal age and access to resources, and offspring age, sex and quality) were varied systematically in seven populations—three industrialized and four small-scale. Despite considerable variation in responses, we found that three of five main effects, and the two severity effects, exhibited statistically significant industrialized/ small-scale population differences. All differences could be explained as adaptive solutions to industrialized versus small-scale caretaking environments. Further, we found gradients in the relationship between the population-specific estimates and national-level socio-economic indicators, further implicating important aspects of the variation in industrialized and small-scale caretaking environments in shaping heuristics. Although there is mounting evidence for a genetic component to human maternal behaviour, there is no current evidence for interpopulation variation in candidate genes. We nonetheless suggest that heuristics guiding maternal behaviour in diverse societies emerge via convergent evolution in response to similar selective pressures.

Landscape characteristics influencing the genetic structure of greater sage-grouse within the stronghold of their range: a holistic modeling approach.

Given the significance of animal dispersal to population dynamics and geographic variability, understanding how dispersal is impacted by landscape patterns has major ecological and conservation importance. Speaking to the importance of dispersal, the use of linear mixed models to compare genetic differentiation with pairwise resistance derived from landscape resistance surfaces has presented new opportunities to disentangle the menagerie of factors behind effective dispersal across a given landscape. Here, we combine these approaches with novel resistance surface parameterization to determine how the distribution of high- and low-quality seasonal habitat and individual landscape components shape patterns of gene flow for the greater sage-grouse (Centrocercus urophasianus) across Wyoming. We found that pairwise resistance derived from the distribution of low-quality nesting and winter, but not summer, seasonal habitat had the strongest correlation with genetic differentiation. Although the patterns were not as strong as with habitat distribution, multivariate models with sagebrush cover and landscape ruggedness or forest cover and ruggedness similarly had a much stronger fit with genetic differentiation than an undifferentiated landscape. In most cases, landscape resistance surfaces transformed with 17.33-km-diameter moving windows were preferred, suggesting small-scale differences in habitat were unimportant at this large spatial extent. Despite the emergence of these overall patterns, there were differences in the selection of top models depending on the model selection criteria, suggesting research into the most appropriate criteria for landscape genetics is required. Overall, our results highlight the importance of differences in seasonal habitat preferences to patterns of gene flow and suggest the combination of habitat suitability modeling and linear mixed models with our resistance parameterization is a powerful approach to discerning the effects of landscape on gene flow.

Functionalization of biomineral reinforcement in crustacean cuticle: Calcite orientation in the partes incisivae of the mandibles of Porcellio scaber and the supralittoral species Tylos europaeus (Oniscidea, Isopoda).

In arthropods the cuticle forms an exoskeleton with its physical and chemical properties adapted to functions of distinct skeletal elements. The cuticle of the partes incisivae (PI) in mandibles of terrestrial isopods is a composite of chitin-protein fibrils/fibres and minerals. It consists of an unmineralized tip, a middle region with organic fibrils reinforced mainly with amorphous calcium phosphate and a base region mineralized with amorphous calcium carbonate and calcite. In this study we extend our work on the structure and material properties of the incisive cuticle employing electron backscatter diffraction (EBSD), and investigate calcite orientation patterns in the PI of two terrestrial isopod species from different habitats. We trace small-scale differences in texture sharpness and calcite microstructure, and compare calcite organization and orientation patterns in the PI with those in the tergites of the same isopod species. We observe that in the PI calcite orientation, the degree of crystal alignment, and mode of crystalline domain assemblage is highly varied within short length scales. This contrasts to calcite organization in the tergite cuticle, where calcite has only one specific texture pattern. Such a large range in the variation of calcite organization has not been observed in other carbonate biological hard tissues, such as shells and teeth, where one specific texture and microstructure prevails. Thus, the investigated isopod species are able to control crystallization of the amorphous carbonate precursor in a differential way, most probably related to the function of the individual skeletal element and the animals' behavior.

Location, location, location: small shifts in collection site result in large intraspecific differences in macroalgal palatability

The role of herbivorous fishes in coral reef resilience has increased interest in the process of herbivory and has focused attention on herbivore feeding behavior, making it important to evaluate experimental methods used to assess herbivore decisions. We tested whether small-scale differences in collection site play a role in within-species palatability of macroalgae. Baseline grazing assays using algae collected on a fringing reef in Moorea, French Polynesia, revealed that herbivore preferences among three common species ranked Padina boryana > Sargassum mangarevense ≫ Amansia rhodantha. Comparing grazing preferences between individual thalli of the same species collected <15 m apart revealed that consumption of intertidal S. mangarevense was nearly six times greater than for conspecifics collected from the adjacent subtidal reef flat. The same trend occurred for P. boryana but was not significant. This demonstrated that algal palatability can vary on a very small spatial scale, presenting a potential trap for the unwary when setting up experiments; we encourage researchers to consider this potential complication in experimental studies of herbivory.

An experimental assessment of herbivory and nutrient effects on a small-scale in a coral reef macroalgal community

Understanding spatial variation in top–down vs. bottom–up control may help resolve some of the conflicts among research findings on the controlling processes of marine plant communities. In this study, I manipulate herbivory and nutrient limitation on assembled communities of coral reef macroalgae. I conducted two identical 10-day manipulative experiments 20m and 12 days apart and measured change in biomass of the 4 assembled species, Padina boryana (Thivy), Halimeda opuntia (L. J.V.Lamouroux), Galaxaura divaricata (L. Huisman and R.A.Townsend), and Dictyota bartayresiana (J.V.Lamouroux). I found that the response of all individual species varied markedly between the two sites. Between the two sites, P. boryana and D. bartayresiana responded differently to manipulations whereas H. opuntia and G. divaricata differed in growth magnitude and variance. The difference in final biomass between the two sites was most pronounced for the opportunistic algal species, suggesting small-scale spatial variation might be more important for these types of macroalgae. The constant environmental conditions during the study period suggest that small-scale spatial differences may affect the processes controlling community structure.

Measurements of persistent organic pollutants in Estonian ambient air (1990–2013)

Central and Eastern Europe is a region that is expected to need more data on the concentrations of persistent organic pollutants (POPs) in the ambient air in the future. Passive air sampling is a cheap screening method for comparison of contamination on various sites or for verification of information obtained by active samplers. Passive air samplers are sensitive enough to mirror even small-scale differences, which makes them capable of monitoring spatial, seasonal, and temporal variations. Different passive air samplers were employed between 1990 and 2013 from time to time in six Estonian air monitoring stations. The concentrations of PCB and its congeners, HCB, PeCB, HCH, and DDT (the same for PBDE, PCN, PCDD/F) in Estonian ambient air were very low, but they allow tracking transboundary air pollution. The main aim of this article is analysis of changes in the ambient air pollution in Estonia during a long period of time (1990-2013). Also, selection of Lahemaa background station for monitoring POPs in the European area is addressed.

Testing of a single grain OSL chronology across the Middle to Upper Palaeolithic transition at Les Cottés (France)

The timing of the Middle Palaeolithic to Upper Palaeolithic transition in France is important to help understand when, where and how Neanderthals have been replaced by Homo sapiens. Radiocarbon dating has been the dating workhorse in constructing the chronological framework pertinent to these questions. In this study, we are testing whether single grain OSL dating has the accuracy and precision to be useful as a complementary dating method. The site of Les Cottés provides an ideal testing ground because of its stratigraphic integrity and reliable radiocarbon chronology. We applied single grain OSL dating of quartz to 19 samples and multi-aliquot MET-pIRIR dating of potassium-rich feldspar grains to 5 samples to explicitly test assumptions of pre-depositional resetting of the OSL signal and post-depositional exposure to variable beta dose rates. The good agreement between the single grain OSL and the multi-aliquot MET pIRIR ages suggest that the optical signals of both quartz and feldspar grains were reset prior to deposition and that much of the extra scatter observed in the equivalent dose distribution of quartz grains are likely due to the small-scale differences in beta dose delivered to individual grains. Both the quartz OSL and feldspar MET-pIRIR ages show great consistency with the 14C ages on bone collected from the same units. This gives confidence in the measurement and analytical approaches used to derive both the equivalent dose and dose rate, the numerator and denominator, respectively, of the luminescence age equation. These results suggest that a systematic and detailed single grain OSL dating study can have the accuracy and precision that is necessary to play a powerful role in the dating of the Middle and Upper Palaeolithic transition and other questions of importance in this time range and geographical area.

Microscale distribution and elemental associations of Se in seleniferous soils in Punjab, India.

Several regions around the globe are known to have soils highly enriched in Se. Usually, bulk samples are analysed when characterizing enrichment and mobility of Se in seleniferous soils. In this study, Se concentration and distribution were determined along with other elements on a microscale level in seleniferous soils from Punjab, India, using synchrotron-based X-ray fluorescence (XRF) analysis. Additionally, the mineralogical and geochemical composition of bulk soil material was investigated. Sequential extractions were carried out to gain further insight into preferential Se associations. The objective of this study was to investigate the microscale geochemistry of seleniferous soils in order to be able to deduce information about Se host phases, to characterize the distribution, extent and origin of Se enrichment and to possibly reveal the relevant enrichment processes. Selenium concentrations in the soils vary considerably within tens of micrometers. Thirty times the bulk concentration, the highest Se enrichment was found to be 350mg/kg. Results show that the primary origin of Se in these soils is probably not from weathering of bedrock or alluvium but rather from an external Se source, like Se-rich irrigation water. Secondary processes like in situ formation of mineral phases, adsorption or transformation to organic species finally lead to an immobilization and fixation of Se in the soils. In this context, reduction of Se oxyanions to elemental Se or to selenide as part of sulfides probably leads to the highest Se enrichment which, however, is mainly spatially confined. Lower Se enrichments are indicated to be due to (co-)precipitation with or adsorption to calcite. Therefore, this extremely heterogeneous distribution of Se must be controlled by small-scale differences in redox and solution chemistry which can develop in small soil structure like micropores or soil aggregates.