Os Espodossolos são os solos de maior ocorrência na planície costeira do litoral do Estado de São Paulo e são caracterizados pela presença de um horizonte espódico (Bh ou Bhm). Poucas são as informações relacionadas à gênese destes solos em regiões tropicais, assim como da composição química da matéria orgânica (MO) nos mesmos e da influência dos micro-organismos em sua formação. É possível que micro-organismos envolvidos na degradação seletiva da MO sejam importantes para a gênese de Espodossolos, como observado anteriormente em Espodossolos de Bertioga e Ilha Comprida. O primeiro estudo teve como objetivo avaliar a variação espacial da estrutura das comunidades e a abundância de bactérias e fungos em três perfis de Espodossolos sob drenagem intermediária, nos diferentes horizontes e nas manchas brancas através de PCR-DGGE e quantificação por qPCR dos genes rRNA 16S de bactérias e ITS de fungos. O segundo estudo teve como objetivo avaliar a variabilidade espacial das comunidades de bactérias nos horizontes e nas manchas brancas de Espodossolos sob três regimes de drenagem, e determinar se a diversidade genética e estrutura das comunidades de bactérias estão associadas à composição molecular da MO nessas regiões, através do sequenciamento massivo da região V4 do gene do rRNA 16S de bactéria e análise de compostos orgânicos por pirólise-GC/MS. As estruturas das comunidades bacterianas, determinada por PCR-DGGE, nos diferentes horizontes de cada perfil foram mais similares entre si do que nos mesmos horizontes em diferentes perfis de Espodossolos. A estrutura das comunidades fungos não apresentou diferenças significativas, independente da localidade do perfil e profundidade dos horizontes. A abundância de cópias do gene rRNA 16S e região ITS, determinada por qPCR, foi maior no horizonte A do que no horizonte Bh, para os três perfis de Espodossolos estudados. Apesar de não haver diferenças significativas na estrutura das comunidades, grupos específicos de bactérias e fungos podem estar envolvidos na degradação seletiva da matéria orgânica nos diferentes horizontes, bem como nas manchas brancas e suas adjacências. A estrutura das comunidades de bactérias, determinada por sequenciamento massivo do gene rRNA 16S, nos horizontes mais superficiais (A e AE) foi distinta daquela observada nos horizontes mais profundos (EB, BE e Bh). Porém, as comunidades bacterianas nas manchas brancas e suas regiões adjacentes foram mais similares entre si, do que em relação as comunidades bacterianas nos horizontes, em todos os perfis analisados, independente do regime de drenagem. Acidobacteria, Proteobacteria e Actinobacteria foram os filos mais abundantes nos solos estudados. Actinobacteria e Alphaproteobacteria mostraram associação positiva com moléculas orgânicas derivadas da pirólise da lignina, as quais foram mais abundantes nos horizontes superficiais (A e AE), enquanto Acidobacteria mostrou associação positiva com compostos mais recalcitrantes encontrados em horizontes mais profundos (Bh), sugerindo um papel específico e diferenciado de cada grupo bacteriano na degradação de compostos orgânicos específicos. Os resultados desses estudos sugerem que grupos bacterianos específicos podem estar envolvidos na gênese de Espodossolos através da degradação de compostos orgânicos específicos em diferentes horizontes. / Podzols are highly frequent soils in the coastal plains of the São Paulo State, and are characterized by the presence of a spodic horizon (Bh or Bhm). Studies on the pedogenetic processes in Podzols of tropical regions are scarce, as well as studies on the molecular characterization of their organic matter (OM) and on the microorganisms involved in their genesis. It is possible that microorganisms involved in the selective degradation of the soil OM are important for the genesis of Podzols, as previously observed in Podzols of Bertioga and Ilha Comprida. The aim of the first study was to evaluate the spatial variation of the community structure and abundance of bacterial and fungi in the different horizons, bleached mottles and their immediate vicinity of three Podzol profiles under intermediary drainage regime, using PCR-DGGE and qPCR of the bacterial rRNA 16S gene and fungal ITS region. The aim of the second study was to determine the spatial variability of the bacterial communities in the horizons and bleached mottles of Podzols under three drainage regimes, and whether the bacterial genetic diversity and community structure were associated to the molecular OM composition, using high-throughput sequencing of the V4 region of the bacterial 16S rRNA gene and analyses of organic compounds by pyrolysis GC/MS. The structure of bacterial communities, determined by PCRDGGE, in the different horizons of each soil profile were more similar to each other than in the same horizons of different soil profiles. The fungal community structures did not show significant differences, independent of the soil profile location and horizons depth. Abundance of copies of the bacterial 16S rRNA gene and fungal ITS region, determined by qPCR, was higher in the A horizon than in the Bh horizon, for the three Podzol profiles studied. Even though there were no significant differences in community structures, specific groups of bacteria and fungi may be involved in the selective degradation of organic matter in different horizons, bleached mottles and their immediate vicinity. The bacterial community structures, determined by highthroughput sequencing of the 16S rRNA gene, in the surface horizons (A and AE) were distinct of that in the deeper horizons (EB, BE and Bh). However, the bacterial community structures in the bleached mottles and their immediate vicinity were more similar to each other than to the community structures in the horizons, in all profiles studied, regardless of the drainage regime. Acidobacteria, Proteobacteria and Actinobacteria were the most abundant phyla in the soils studied. Actinobacteria and Alphaproteobacteria showed a positive relationship organic compounds derived from lignin degradation, which were more abundant in the surface horizons (A and AE), whereas Acidobacteria showed a positive relationship with more recalcitrant compounds detected in deeper horizons (Bh), suggesting a specific and distinct roles of each bacterial group in the degradation of specific organic compounds. The results of these studies suggest that specific bacterial groups may be involved in the genesis of Podzols by degrading specific organic compounds in different horizons.

Les mécanismes d’interactions entre uranium et colloïdes ont été étudiés à partir d’échantillons provenant d’un site d’intérêt pour le Commissariat à l’Energie Atomique (CEA). La mobilisation de l’uranium depuis les sols a été appréhendée par lixiviations statique et dynamique. Le transfert et le transport ont été investis en considérant les eaux de nappe et de surface (drain). Les résultats confirment que l’uranium anthropique est plus mobile que l’uranium naturel. Le comportement (mobilisation, distribution) de l’uranium ne diffère cependant pas selon son origine. La phase colloïdale joue un rôle non négligeable dans la migration dans le sol et le transfert vers les eaux, représentant de 10 à 90 % de l’uranium suivant les échantillons. Les phases porteuses de l’uranium sont dans un continuum de taille allant jusqu’à environ 200 nm de diamètre hydrodynamique. Elles sont principalement composées de matière organique, de fer et d’aluminium. Le long du drain, de l’amont à l’aval du site, un réarrangement des associations colloïdales uranium-matière organique se fait en défaveur de celles uranium-fer, la proportion d’uranium colloïdale lié à l’aluminium restant elle inchangée. / Mechanisms of interaction between uranium and colloids were studied by samples taken from a site of interest for the “French Nuclear Agency” (CEA). The mobilization of uranium from soils was apprehended by static and dynamic leaching experiments. The transfer and transport have been studied by considering pondwaters and drainwaters. Results confirm that anthropogenic uranium is more mobile than natural uranium. However mechanisms of mobilization and distribution of uranium, does not differ depending on its origin. The colloidal fraction plays an important role on the migration in soil and the transfer into water by representing from 10 to 90 % uranium depending on samples. The colloidal fractions of uranium are in a continuum of size up to about 200 nm hydrodynamic diameter. They are mainly composed of organic material, iron and aluminum. Along the drain, from the upstream to the downstream of the site, rearrangement of colloidal associations between uranium and organic material occurs in disfavor of colloidal associations between uranium and iron, the proportion of colloidal uranium bound to aluminum remains unchanged.

The reaction of sulfate with six podzolic horizons of the Southern Laurentians (Quebec) was investigated using batch reaction techniques. It was demonstrated that sulfate sorption increased with decreasing solution pH to a maximum sorption capacity at around pH 4.0; below this pH retention decreased. This drop in sorption capacity was related to the partial dissolution of Al surface coatings. Indeed, the amount of native sulfate and the maximum sorption during the experiment were positively correlated (R$ sp2$ = 0.982, 0.800) with the oxalate extractable Al content of these forested soils. In all six horizons, the increase in sulfate sorption as a function of equilibrium sulfate concentration was best described by the Gunary equation. Kinetic experiments showed the presence of two major stages in both sorption and desorption reactions with an initial quick change (first 6 h) in solution concentration being followed by a second step where the reactions between sulfate and the soil matrix were much slower. The time-dependence of these reactions emphasized the appropriateness of kinetic equation in describing field situations. Moreover, kinetics studies performed under highly acidic conditions demonstrated that the amount of sulfate sorbed decreased with time after an initial sorption step due to the partial dissolution of Al surface materials. Thermodynamic calculations further suggested the subsequent precipitation of jurbanite. It was then concluded that surface dissolution and mineral formation should be considered in the interpretation of results obtained from experiments aimed at determining the effect of pH on sulfate retention.

No description available.

The aim of this study has been to clarify how the radiumdistribution in soils affects the radon emanation. Thedistribution of radium, uranium and thorium has been determinedusing sequential extractions. In the study, soils from twodifferent locations were investigated. In the first part the applicability of the sequentialextraction method for determining Ra distribution in differentsoil types was investigated, using a simple sequentialextraction method. Sampled soils were clay, sand and till fromthe vicinity of the Stockholm Esker. The main part of Rnemanating Ra was associated with Fe oxides in the soil. Themethods applied provided information about the radon risk ofthe soil, but, inorder to gain more information on theprocesses governing Ra distribution and radon emanation insoils, a more detailed sequential extraction procedure would bedesirable. The second part consisted of a detailed study of theradionuclide distribution and the geochemistry in a podzolisedglacial till from Kloten in northern Västmanland. A moredetailed sequential extraction procedure was used, and thespecific surface area of samples was measured. Samples weretaken from E, B, and C horizons; radium and thorium wereenriched in the B horizon, whereas uranium had its maximumconcentration in the C horizon. Extractable radium primarilyoccurred in the exchangeable pool, possibly organicallycomplexed, whereas extractable uranium and thorium were mainlyFe oxide bound. Oxide-bound Ra was important only in the Bhorizon. The radon emanation was not correlated with the amountof exchangeable Ra, but instead with the oxide bound Ra.However, the amount of oxide-bound Ra was too small to accountfor all the emanated Rn, thus, exchangeable Ra was interpretedas the main source of emanated Rn. This exchangeable Ra wasmore emanative in the B horizon than in the C horizon. Theexplanation is the larger surface area of the B horizonsamples; the specific surface area appears to be the maingoverning parameter for Rn emanation in this soil. The surfacearea is largely created by the precipitation of amorphous Feoxides, thus, Fe oxides has a significant effect on Rnemanation. Comparing the two studies, the Stockholm samples had thesame amounts of oxide-bound Fe and surface-bound Ra. Still theradon emanation was much smaller for these samples than in theKloten soil. The amount of organic matter in the B horizon ofthe Kloten soil is however, much larger than the organic mattercontent in the Stockholm samples. It is suggested that thelarge Rn emanation in the B horizon of Kloten is caused by thecombined effect of Fe oxides and organic matter. The variability of226Ra distribution in soils was also investigated.The226Ra distribution was determined for samples from60-70 cm and 80-90 cm depth, from three adjacent soil profilesin a podzolic glacial till. Ra distributions, and estimationsof Rn risk based on the Ra distributions, of a single soilprofile, are likely to be representative for a similar area,provided that the samples are taken from a sufficientdepth. KEYWORDS: distribution, emanation, extraction, glacial till,podzol, Ra, radium, radon, Rn, sequential soil, spodosol, Th,thorium, U, uranium, variability

<p>The aim of this study has been to clarify how the radiumdistribution in soils affects the radon emanation. Thedistribution of radium, uranium and thorium has been determinedusing sequential extractions. In the study, soils from twodifferent locations were investigated.</p><p>In the first part the applicability of the sequentialextraction method for determining Ra distribution in differentsoil types was investigated, using a simple sequentialextraction method. Sampled soils were clay, sand and till fromthe vicinity of the Stockholm Esker. The main part of Rnemanating Ra was associated with Fe oxides in the soil. Themethods applied provided information about the radon risk ofthe soil, but, inorder to gain more information on theprocesses governing Ra distribution and radon emanation insoils, a more detailed sequential extraction procedure would bedesirable.</p><p>The second part consisted of a detailed study of theradionuclide distribution and the geochemistry in a podzolisedglacial till from Kloten in northern Västmanland. A moredetailed sequential extraction procedure was used, and thespecific surface area of samples was measured. Samples weretaken from E, B, and C horizons; radium and thorium wereenriched in the B horizon, whereas uranium had its maximumconcentration in the C horizon. Extractable radium primarilyoccurred in the exchangeable pool, possibly organicallycomplexed, whereas extractable uranium and thorium were mainlyFe oxide bound. Oxide-bound Ra was important only in the Bhorizon. The radon emanation was not correlated with the amountof exchangeable Ra, but instead with the oxide bound Ra.However, the amount of oxide-bound Ra was too small to accountfor all the emanated Rn, thus, exchangeable Ra was interpretedas the main source of emanated Rn. This exchangeable Ra wasmore emanative in the B horizon than in the C horizon. Theexplanation is the larger surface area of the B horizonsamples; the specific surface area appears to be the maingoverning parameter for Rn emanation in this soil. The surfacearea is largely created by the precipitation of amorphous Feoxides, thus, Fe oxides has a significant effect on Rnemanation.</p><p>Comparing the two studies, the Stockholm samples had thesame amounts of oxide-bound Fe and surface-bound Ra. Still theradon emanation was much smaller for these samples than in theKloten soil. The amount of organic matter in the B horizon ofthe Kloten soil is however, much larger than the organic mattercontent in the Stockholm samples. It is suggested that thelarge Rn emanation in the B horizon of Kloten is caused by thecombined effect of Fe oxides and organic matter.</p><p>The variability of²²⁶Ra distribution in soils was also investigated.The²²⁶Ra distribution was determined for samples from60-70 cm and 80-90 cm depth, from three adjacent soil profilesin a podzolic glacial till. Ra distributions, and estimationsof Rn risk based on the Ra distributions, of a single soilprofile, are likely to be representative for a similar area,provided that the samples are taken from a sufficientdepth.</p><p>KEYWORDS: distribution, emanation, extraction, glacial till,podzol, Ra, radium, radon, Rn, sequential soil, spodosol, Th,thorium, U, uranium, variability</p>

Cette thèse a pour but d'améliorer notre compréhension des processus d'altération des roches mafiques silicatées, de la spéciation des éléments et de leur migration dans le milieu boréal (bassin versant de la mer Blanche, Nord-Ouest de la Russie). Les objectifs principales du travail sont i) de caractériser et décrire les mécanismes responsables de l'altération chimique et de la formation des minéraux dans la zone subarctique, ii) évaluer le rôle de la lithologie (environnement granitique versus basaltique) dans la spéciation des éléments traces (ET) et la formation des colloïdes organo-minéraux dans les eaux de surface des bassins versants boréaux des hautes latitudes, et iii) révéler la dépendance de la spéciation des ET en fonction du pH de la solution pour prédire des changements éventuels dans la bioaccumulation des éléments dans les eaux naturelles à cause de leur acidification. L'originalité de cette thèse est de combiner, pour la première fois sur les mêmes objets naturels, les techniques physico-chimique, minéralogique et isotopique afin de mieux comprendre les facteurs qui contrôlent les cycles biogéochimiques des éléments dans les régions subarctiques.

As agrarian society developed, the most fertile soils able to sustain the nutritional requirements needed for high crop yield were assigned to farming, while the more penurious soils were left to uphold the forest ecosystems. Some temperate forests are developed on acidic soils considered to be nutrient poor, as much of the inorganic nutrients are entrapped in poorly weatherable soil minerals and not easily accessed by plant roots. In an undisturbed ecosystem, the largest contribution of available nutrients comes from the recycling of organically bound nutrients via the decomposition of dead plant material. If biomass is removed, for instance with a more intensified exploitation of the forest ecosystems including whole tree harvesting, this source of nutrients is consequently decreased. The importance of soil mineral weathering as a source of nutrients, and especially that promoted by soil biota, is thereby emphasized. This thesis addresses biotic parameters associated with mineral weathering. Different aspects of soil solution sampling strategies and analysis of different organic ligands as well as biomarkers for the estimation of fungal biomass were investigated. These chemical parameters were also evaluated as indicators of microbial activity in relation to mineral nutrient availability in soil. With the assumption that the current nutrient status of a soil will affect the microbial interest of certain minerals as sources of inorganic nutrients, a mineral amendment trial was performed in a Swedish boreal forest soil. Overall, the amended soil presented good nutrient status, but with a possible shortage of iron. Due to this, it was hypothesized that the amended mineral with the highest iron content i.e. biotite would cause an elevation of microbial activity in its vicinity when compared to the bulk soil. The level of microbial activity in the vicinity of the amended minerals was evaluated via quantification of organic acids and siderophores, as well as estimation of fungal biomass and enzymatic activity. The highest microbial activity was measured for the O horizon of the investigated podzol, although nothing indicated an elevated association with the amended minerals. In the E horizon, however, elevation in microbial activity was observed in the vicinity of the biotite mineral when compared with bulk soil, although only a few of the investigated parameters differed significantly when evaluated separately.   To enable this study, a highly sensitive analytical method employing liquid chromatography and mass spectrometry was developed to quantify a number of hydroxamate siderophores. On-line pre-concentration enabled detection of these organic ligands in the pico-molar range – a necessity when analyzing natural samples. Furthermore, an analytical method was developed for the estimation of fungal biomass via quantification of chitin-derived glucosamine, which also employed liquid chromatography and tandem mass spectrometry. Unlike currently available methods, the one presented in this thesis did not involve analyte derivatization, which resulted in high sample throughput while simultaneously avoiding complications involved with the additional derivatization procedure. The distribution of a group of organic ligands known as aromatic low molecular mass organic acids was also studied in a boreal forest podzol soil. Different sampling and samples preparation techniques, namely tension-lysimeters, soil centrifugation and liquid-soil extraction, were compared when analyzing soil solution components. Significant differences in analyte amount and species type were found between these sampling techniques. Some of the differences could be accounted for by variation in soil composition at different depths of the investigated podzol, but others could be attributed to structural differences within the studied analyte group. This clearly illustrated the intricacy of sampling and analysis when working with a sample matrix as complex and diverse as soil. As previously, liquid chromatography and mass spectrometry was used to quantify the analytes of interest. A highly sensitive analytical method was developed that was able to detect eleven aromatic low molecular mass organic acids in the nano-molar range. High selectivity was ensured by applying multiple reaction monitoring enabled by collision induced fragmentation of the analytes. / FORE

This research investigates soil respiration (Rs) in a boreal jack pine (Pinus banksiana Lamb.) fire scar chronosequence at Sharpsand Creek, Ontario, Canada. During two field campaigns in 2006 and 2007, Rs was measured in a chronosequence of fire scars in the range 0 to 59 years since fire. Mean Rs adjusted for soil temperature (Ts) and soil moisture (Ms) (Rs T,M) ranged from 0.56 μmol CO2/m2/s (32 years post fire) to 8.18 μmol CO2/m2/s (58 years post fire). Coefficient of variation (CV) of Rs adjusted for Ts and Ms ranged from 20% (16 years post fire) to 56% (58 years post fire). Across the field site, there was a significant exponential relationship between Rs adjusted for soil organic carbon (Cs) and Ts (P = 1.24*10-06; Q10 = 2.21) but no effect of Ms on Rs adjusted for Cs and Ts for the range 0.21 to 0.77 volumetric Ms (P = 0.702). Rs T,M significantly (P = 0.030) decreased after burning mature forest, though no significant (P > 0.1) difference could be detected between recently burned and unburned young forest. Rs was measured in recently burned boreal jack pine fire scar age categories that differed in their burn history and there was a significant difference in Rs T,M between previously 32 v 16 year old (P = 0.000) and previously 32 v 59 year old (P = 0.044) scars. There was a strong significant exponential increase in S R T,M with time since fire (r2 = 0.999; P = 0.006) for the chronosequence 0, 16 and 59 years post fire, and for all these age categories, Rs T,M was significantly different from one another (P < 0.05). The Joint UK Land Environment Simulator (JULES) was used to model vegetation re-growth over successional time at Sharpsand Creek, though it appeared to perform poorly in simulating leaf area index and canopy height. JULES probably over estimated heterotrophic Rs at Sharpsand Creek when Ts corrected simulated values were compared with measured Rs T,M. The results of this study contribute to a better quantitative understanding of Rs in boreal jack pine fire scars and will facilitate improvements in C cycle modelling. Further work is needed in quantifying autotrophic and heterotrophic contributions to soil respiration in jack pine systems, monitoring soil respiration for extended time periods after fire and improving the ability of JULES to simulate successional vegetation re-growth.

The Sámi’s past activities have been documented historically from a European perspective, and more recently from an anthropological viewpoint, giving a generalised observation of the Sámi, during the study period of AD200-AD1800, as semi-nomadic hunter gatherers, with several theories suggesting that interaction with Europeans, through trade, led to the adoption of European activities by certain groups of the Sámi (Eiermann, 1923; Paine, 1957; Manker and Vorren, 1962; Bratrein, 1981; Mathiesen et al, 1981; Meriot, 1984). However, there is almost no information on the impact the Sámi had on the landscape, either before or after any adoption of European activities, and none investigating what cultural footprint or indicators would remain from Sámi or European occupation and/or activity within the typically podzolic soils of Northern Sweden. Consequently the thesis aims to contribute to the gap in knowledge through the formation of a podzol model identifying the links between anthropogenic activity and the alteration of podzol soils, and through the creation of soils based models which identify the cultural indicators associated with both Sámi and European activity; formed from the identification of cultural indicators retained within known Sámi and European sites. The methods used to obtain the information needed to achieve this were the pH and magnetic susceptibility from bulk soil samples and micromorphological and chemical analysis of thin section slides through the use of standard microscopy and X-ray fluorescence from a scanning electron microscope. The analysis revealed that the Sámi had an extremely low impact on the landscape, leaving hard to detect cultural indicators related to reindeer herding in the form of reindeer faecal material with corresponding phosphorous peaks in the thin section slides. The European footprint however, was markedly different and very visible even within the acidic soil environment. The European indicators were cultivation based and included phosphorous and aluminium peaks as well as a deepened, highly homogenised plaggen style anthropogenic topsoil rich in ‘added’ materials. An abandoned European site which visibly and chemically shows the formation of a secondary albic horizon within the anthropogenic topsoil also provides an insight into the delicate balance of cultivated soil in northern Sweden, whilst reinforcing the outputs identified in the podzol model. Due to the almost invisible Sámi footprint on the landscape, areas of overlap were impossible to identify however, there was no evidence of the adoption of European cultivation activities at any of the Sámi sites investigated. The only known area of interaction between the two cultures was an official market place which had been a Sámi winter settlement prior to its use as a market site. This site showed none of the reindeer based Sámi indicators or the cultivation based European indicators, but did contain pottery fragments which could be linked to trade or occupation. Overall, the thesis reinforces the low impact expected of the semi-nomadic Sámi and sheds light on the underlying podzolic processes influencing the anthropogenically modified soils of Northern Sweden. The podzol model is reinforced by several findings throughout the thesis and the soils based cultural indicator models for both Sámi and European activity have been successfully tested against independent entomological and palynological data and therefore provide reliable reference material for future studies.