Title Promoter Affiliations Abstract "Effects of sediment-bound metal mixtures on metal uptake and sublethal toxicity in benthic invertebrates and its impact on ecosystem functioning." "Maarten De Jonge" "Systemic Physiological and Ecotoxicological Research (SPHERE)" "The aim of the present project is to study effects of sediment-bound metal mixtures on benthic invertebrates, both in terms of metal uptake kinetics and bioaccumulation, aerobic respiration and bioturbation and its influence on key ecosystem processes." "The importance of flood events and floodplain processes for the dynamics of organic carbon transport and processing in large tropical rivers systems." "Gerard Govers" "Division of Geography and Tourism, Division of Geology, Nuclear and Radiation Physics, Division of Soil and Water Management" "Recent research has highlighted the importance of rivers within the global carbon cycle. Rivers not only transport considerable amounts of carbon to the ocean thereby connecting the terrestrial and oceanic component of the carbon cycle. Rivers can also be looked as important reactors as a large fraction of the carbon that enters the fluvial system does not reach the ocean due to within-river mineralisation of floodplain deposition. Our understanding of the role of rivers in the carbon cycle is, however, still very limited. River systems have hitherto mainly been studied through longitudinal survey whereby differences in sediment/carbon concentrations from the headwaters to the mouth are used to make inferences about the dynamics of carbon within the river system. While it is certainly true that important insights can be gained from such surveys, they neglect two very important components of river systems. The first is that rivers show a very high temporal variability in discharge and that most of the sediment and carbon is transported during so-called flood events, often grouped in flood pulses. During such flood events, sediment concentrations and carbon transport may vary drastically and it is simply impossible to assess the impact of these events on carbon transport and carbon cycling from a limited number of surveys. A second aspect to consider is that rivers cannot be seen in isolation: a large amount (often > 50%) of the sediment and carbon that they transport is deposited on floodplains where the carbon may be stored and/or mineralized. It is not possible to make a comprehensive carbon budget for a river system without accounting for the processes occurring in floodplain environments. This project will therefore focus on the temporal variability of river carbon and sediment fluxes and the role of floodplains in sediment and carbon storage and cycling within lower part of the Tana river, Kenya. This river section was chosen because (i) it has a clear flood season with several flood events and (ii) it has extensive floodplains in which sediment is stored, and (iii) due to earlier work in this catchment, we have sufficient local experience and data to guarantee the success of our proposed approach. We will use a unique combination of advanced biochemical and physical techniques to characterize the carbon and sediments transported in the river and deposited on the floodplain. By combining these data with information from radionuclide analysis we will be able to (i) quantify and understand the role of flood events in sediment and carbon throughput, (ii) understand how sediment remobilisation may affect sediment transport and carbon dynamics and (iii) quantify t he role of floodplain sedimentation in the rivers carbon and sediment budget." "Application of Sm-Nd and Lu-Hf isotope systems in geological and archeometric research." "Philippe Muchez" "Division of Geology" "The questions where materials come from and how old they are, are crucial to studies of natural and man-made materials, which belong to the fields of geology and archaeometry. The steady decay of radioactive isotopes causes natural variations in the isotope ratio of certain elements, such as neodynium (Nd) and hafnium (Hf). These variations can be accurately determined by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS), and help to source and date materials. This is used for various purposes. Ore deposits in e.g. the Central African Copperbelt are associated with carbonate veins, and their Nd isotopic composition is likely to identify possible sources of their elemental contents, and by inference, the source of associated copper and cobalt mineralisation. The Hf isotopic composition of such veins could potentially tell when they formed. Combining Hf and Nd isotopic studies will shed light on the varying contributions of the Earths mantle and crust to magmas erupted in volcanic areas such as the Aegean Arc. Finally, Nd isotope ratio can help to determine the source of archaeological artefacts, such as Hellenistic-Roman glass and Bronze Age pottery." "Antique pollution on the territory of Sagalassos as a proxy for human activity." "Philippe Muchez" "Division of Geology" "Ancient human activities such as metal smelting, food consumption and refuse dumping have resulted in the addition of a wide range of organic and inorganic materials to soils at occupation areas, thereby altering their geochemical composition. These additions can be detected up to the present day, and hence provide a tool to address archaeological questions. While geochemical soil studies have frequently been applied on exposedfloor layers at archaeological sites, they have rarely been considered within the research domain of archaeological prospection, where they could serve as a means for providing information on the buried archaeological record. This thesis assesses the potential of this approach on several sites in the Roman to Byzantine city of Sagalassos (SW-Turkey), which offers an excellent test location because of its extended archaeologicalhistory, varying physical landscape and well-developed scientific framework. As several studies have recommended the integration of different survey methods in order to obtain a more objective understanding of the history of buried sites, special emphasis is put on the use of a multi-analytical approach.Three main research aims were put forward in this thesis. We evaluated how the chemical composition of soils on unexcavated sites at Sagalassos was altered by ancient human activities (1). Also, we studied to which extent soil geochemical data are useful in providing information on the former functionality of (zones within) archaeological sites at Sagalassos (2). Finally, we examined the potential of integrating soil geochemical survey with other survey techniques (3). To answer these research questions, we performed geochemical surveys on fourstudy areas, each with a different historical and geological context. The first site subjected to a soil survey was Catal Oluk, which is an isolated rural site, seemingly not directly influenced by pollution inputs from the city. Next, samples were taken at the Eastern Suburbium, an area situated in the east of the ancient city of Sagalassos. This area has witnessed a variety of intense human activities over a long period of time. Thirdly, a survey was performed in a large area west of the Colonnaded Street. Finally, samples were collected at Gökpinar, an area rich in bloated ceramic slag and with an unknown functionality at the time of geochemical soil survey.From a methodological point of view, we combined soil multi-element chemistry (ICP-OES analyses after Aqua Regia destructions) with the analysis of additional parameters, such as pH, organic matter, Pb-isotopes and mineralogy. Also, emphasis was put on developing a suitable statistical approach, which included boxplots, correlation analysis, principal component analysis, Wards clustering, contiguity constrained clustering and parallel coordinate plots. These techniqueswere applied to compare chemical data with local background values, study chemical associations, define (spatial) groups and identify inter-group chemical differences. To study the potential of integrating chemical survey with other techniques, chemical data were combined with results from magnetic- and archaeological surveys in the study areas.For the site of Catal Oluk, the results revealed anomalies of K, P and Zn ona location where archaeological and geophysical data suggested the presence of ceramic producing kilns. These enrichments are thought to resultfrom burning wood as fuel for the detected kilns; In addition, local anomalies of Co, Cr, Fe, Mg, Mn and Ni were found to reflect the working and storage of ophiolitic clays, which were employed as a raw material for ceramic production. Changes in Al, As, Ba, Ca, Na, Pb, Sr and Ti-content were attributed to the combined contribution of limestone and volcanic tuff fragments.In a first sampling grid constructed in the Eastern Suburbium, an area with ancient human enrichments of Cu, P, Zn and K was detected. This area was distinguished from natural patterns created by limestone and volcanic tuff (Al, Pb, Ba, As, Sr) and ophiolitic bedrock material (Co, Cr, Ni, Mg, Fe, Mn and V), but no specific interpretations regarding ancient functionality could be made. In a second, more detailed grid, a more detailed research question was put forward, i.e. offering an explanation for an area in which the magnetometry image was difficult to interpret. It was demonstrated that a zone characterised by high frequency magnetic anomalies and a low variogram-range was associated with chemical anomalies of Cu, K, P, Zn and potentially also Pb. This contributed to the interpretation of this zone as an area of magnetic disturbance created by occupational debris. Next, a zone with a low magnetic signal and low sill-values could be interpreted as a region where limestone bedrock is located close to the soil surface, based on the association with a cluster high in Al, Ba, As and Pb. Finally, two zones of enhanced magnetization and high range- and sill values were shown to spatially overlap with two clusters of soils containing elevated levels of Co, Cr, Mg, Mn, Ni and Ti, V and Fe respectively. By combining these chemical data with magnetic susceptibilities and X-ray diffraction patterns, it is shown that these two zones were the result of the presence of two partly different types of ophiolitic material near the surface.The grid west of the Colonnaded Street aimed to evaluate the characteristics and spatial extent of an ancient pollution signal in the surroundings of this street. Cu, P, Pb and Zn were shown to be enriched around the Colonnaded Street. While enrichments of Zn and Cu were weak or limited to a few samples, P and Pb were strongly anomalous, reaching values respectively 2 and 3 times higher than maximum background concentrations. Thespatial extent of the pollution signal was different for P and Pb, withPb reaching background values at 150 m away from the street, while P was at background levels at 450 m away from the street. Two explanations were put forward to explain this difference. The first assumes that all anthropogenic P and Pb stem from activities in and aroundthe ancient citycentre and the Colonnaded Street, and that surface runoff processes transported P to larger distances when compared to Pb due to differences in partitioning of P and Pb between the solid-liquid phases in the soil. The second option assumes that the high P concentrations in a zone west ofthe monumental centre are the result of direct P input in the soil, as the area functioned as a residential quarter in ancient times. This scenario hence suggests that the activities in the monumental centre and thewestern residential quarter were different in such a way that only those in the monumental centre resulted in Pb input in the soil. A link withmetallurgical activities around the city centre can be put forward to explain this difference, although contributions by other activities cannot be excluded.The research in the Gökpinar area aimed to providebetter insights in the functionality of this site. However, no enrichments of potentially anthropogenic elements were found. Observed chemical patterns in the sampling grid were ascribed to geological variations within the Gökpinar area, with ophiolitic bedrock material outcropping in the south and limestone rocks outcropping in the north of the grid. This conclusion is consistent with the results of a recent survey campaign, suggesting that the Gökpinar area mainly functioned as an access road towards the Eastern Suburbium.The potential of Pb-isotopes to distinguish between polluted and unpolluted soil samples at Sagalassos was evaluated in a separate chapter. It was concluded that soils strongly polluted due to ancient human activities may sow a limited shift in their Pb-isotopic composition. However, the isotopic data did not provide new information on potential ancient pollution sources in the study areas, andtheir applicability as tracers of ancient pollution in Sagalassos appears to be limited. There are several reasons for this, with the broad andoverlapping isotopic fields of background data being one of the most important factors complicating interpretations.More in general, the results of this thesis show that Cu, K, P, Pb and Zn are locally enriched due to ancient activities, with P being the most reliable indicator of human activity. Inter-site differences are a consequence of changes in bedrock composition and archaeological history. When applied as a standalone technique, problems of superposition and mixing at the site level, and inconsistencies in literature data regarding specific element-functionality relations, prevent the use of geochemical data as interpretational tools on most of the sites investigated in this thesis. It is expected that this conclusion holds for many other sites influenced by a longhistory of human occupation. However, when combined with other survey techniques, such as geophysical prospection, soil geochemical survey is shown to have much more potential. Because geochemical information is to a certain extent diagnostic for the subsurface features creating geophysical anomalies, geochemical data are highly valuable indistinguishing geogenic and anthropogenic anomalies. This thesis emphasises the value of using an integrated multivariate data analysis approach. In addition, itis demonstrated that taking into account the spatial component of the chemical datasets in the statistical analyses significantly enhances the quality of the data analysis results." "Effect of grazing on the biological silicon buffer in subarctic ecosystems (Finnmark, Northern Norway)." "Patrick Meire" "Ecosystem Management" "Recently, the biological loop in the terrestrial Si cycle, the ""biological Si buffer"", has been shown to regulate the terrestrial Si export towards coastal systems. Studies on the functioning of this Si buffer and influences of human activities are currently scarce, incomplete, while scale-effects are unknown. This project will be a pioneer study on the effect of grazing on the functioning of the biological Si buffer in three subarctic bio-Si hotspot ecosystem types. The study will integrate four different scales, ranging from the plant-herbivore scale to the scale of the province Finnmark. Through combination of the most recently developed analysis methods, Si stocks and fluxes will be analyzed quantitatively and qualitatively. Combined analysis on N, P and DOC will integrate the results with the biogeochemical cycles which are relevant in the light of marine primary production and the global climate. The end-result will be an integrated insight in the effect of grazing and land cover on biological Si pools and fluxes of Si in subarctic ecosystems. The results will be coupled in a modelling environment which will allow to predict Si fluxes with changing land cover, grazing intensity and climate. Today, these changes are highly relevant in subarctic regions." "Evolution of the deep-sea ecosystem during early Eocene transient warming events: stable-isotope and foraminiferal evidence." "Robert Speijer" "Division of Geology" "During the late Paleocene-early Eocene (60-50 Ma), earth experienced the warmest conditions of the Cenozoic. Especially middle and high-latitude temperatures were much higher than today. Superimposed on this setting, a transient warming event (hyperthermal), known as the Paleocene-Eocene thermal maximum (PETM; 55 Ma), left a major mark on biogeosphere development. Recent studies show that several subordinate hyperthermals occurred in the late Paleocene-early Eocene. The two best known hyperthermals are known as ETM-2 and ETM-3. Yet, ETM-2 and -3 are largely unexplores with respect to their biotoc aspects and short- and long-term consequences. In collaboration with various national and international partners the early Eocene hyperthermals are currently being investigated in continental margin sequences, especially in marginal basins of the Tethys and Atlantic Ocean. In the current proposal the bathymetric range of our studies is expanded to the deep sea (based on DSDP and ODP material) in order to obtain a more complete overview of the consequences of global warming and changes in oceanic circulation to the continuum of marine benthic ecosystems." "The 4D diagenetic and petrophysical behavior of cold-water carbonate bodies in deep environments (4D-PETROCARDE)." "Rudy Swennen" "Division of Geology" "The glass of Herculaneum: a true Roman glass production?" "Patrick Degryse" "Division of Geology" "mso-bidi-font-family:""Times New Roman"""" lang=""EN-GB"">mso-bidi-font-family:""Times New Roman"""" lang=""EN-GB"">Raw natron glass was traded throughout the Roman Empire as chunks, remelted, coloured and/or decoloured if desired, and shaped into finished objects in secondary workshops. Primary production centres, active from the 4th to 8th centuryAD, were identified in Egypt and Syro-Palestine. However, the location of primary production centres in the Hellenistic and early Roman world is still a subject of intense debate. Ancient authors, such as Strabo andPliny the Elder, suggest that glassmaking sands were found near the Belus River (Israel) and in Egypt, but also along the coasts of Spain and France and near the mouth of the Volturno River (Italy). Primary production in the western Mediterranean is not supported by any direct archaeological evidence so far, but the possibility to produce glass using sand raw materials from these regions has been recently evaluated. Results show that suitable glass making beach sands are far from common, and are mainly located in a few locations in Basilicata and Apulia regions (SE Italy) and Tuscany (W Italy), as well as in southern Spain and Provence (France).Over the past decades, different approaches have been attempted to provenance the raw materials used in glass making and to determine the locations of primary production centres. Particularly promising is the combined use of Sr and Nd isotopic analyses and elemental analyses, with particular attention to sand-related trace elements such as Ti, Cr, Sr, Zr, and Ba.The present work investigates the possible existence of primary Roman glass making centres along the Italian peninsula. The sample set includes a total of 176 glass fragments excavated in the Romantowns of Augusta Praetoria, Potentia, Pompeii and Herculaneum, and materials from the cargos of the Iulia Felix and Embiez shipwrecks. These samples date from the 1st to 4th century AD and include both coloured and colourless glass.The extraordinary compositional consistency of Roman natron glass analyzed here and the principal compositional groups widespread on Mediterranean sites tend to support the model of the centralised production, organized in a small number of primary workshops, which supplied raw glass to a great number of secondary workshops where the glass was re-melted and shaped into objects. The emerald green glasses appear to represent an exception. Their different compositions, that may involve the use of plant ash rather than natron as a fluxing agent, reflects the use of a dedicated technology for the production of this particular colour present only in the 1st century AD. Manganese and antimony, thetwo main decolouring agents in ancient times, were used for making colourless glasses. The study defines a timeline for the use of the two decolouring agents, pointing to the use of manganese already during the 1st century AD, in contrast to its later introduction suggested in literature.To explore the provenance of raw materials, a combined approach, using alumina contents, trace elements patterns and Sr-Nd isotopic signatures, has been followed. The results obtained for the glass samples discussed here have been compared to the known 4th to 8th century AD Egyptian and Syro-Palestinian primary glasses and to a database which includes suitable glass making sands across the Mediterranean. These data suggestthat the vast majority of Roman glasses analysed in this study were likely produced in workshops situated along the Syro-Palestinian coasts, while a different silica source is suggested for Sb-decoloured glasses. Atpresent neither Syro-Palestinian nor southern Italian sands can be excluded. The use of different sand sources for Sb-decoloured glass indicates a careful selection of raw materials and the existence of specialized workshops for their production. The Augusta Praetoria glass samples are more difficult to interpret. The provenance of a silica source with highCr content is still unclear, and neither the eastern Mediterranean nor the southern Italian hypothesis can be excluded at present.A significant part of this doctoral work also has been dedicated to the definition of a simple, rapid and practical analytical protocol for the isolation of Nd from complex glass matrixes. Accurate isotopic measurement requires target element purification prior to mass spectrometric analysis using MC-ICP-MS. Whereas the extraction chromatography separation of Sr from concomitant matrix is well established, this was not the case for Nd. A series of tests were performed to better understand the dependence of the elution profile on the amount of resin and column type. Differentcolumn shapes indeed modify the elution profile. The selection of the correct HCl concentration to be used for Nd elution has proved to be of maximum importance. Small differences in HCl concentration modify significantly the elution rate, and could be responsible for sample loss. Lastly, the possibility to regenerate up to four times the resins involved inthe separation protocol has been evaluated." "Integrating the biological Si buffer into biogeochemical models." "Patrick Meire" "Ecosystem Management" "This project will contribute essential knowledge to our scientific concept of the bio-Si buffer, and attain an integration of this buffer into biogeochemical models of the silica cycle. This requires a detailed quantification of the reactivity of the bio-Si buffer in different ecosystems and at different timescales, as well as an integration of processes at different temporal and spatial scales." "The chaîne opératoire of ancient glass production: archaeometry and archaeology of Hellenistic and Roman natron glass." "Patrick Degryse" "Division of Geology" "In this project, innovative techniques to reconstruct ancient economies are developed and new insights in the trade and processing of raw materials are gained based on interdisciplinary archaeological and archaeometrical research. An innovative methodology for, and a practical database of, the primary provenance of natron glass from the Hellenistic-Roman world will be established. The project investigates both production and consumer sites of glass raw materials using both typo-chronological and archaeometrical (isotope geochemical) study of finished glass artefacts at consumer sites as well as mineralogical and chemical characterisation of raw glass and mineral resources at primary production sites. Suitable sand resources in the locations described by Pliny the Elder in his Natural History will be identified through geological prospecting on the basis of literature review and field work. Sand deposits will be mineralogically and geochemically characterised and compared to the results of the archaeological and geochemical investigations of the glass. Through integrated typo-chronological and archaeometrical analysis, the possible occurrence of primary production centres of raw glass outside the Levant and Egypt, in Italy, Spain and Gaul will be studied. In this way, historical, archaeological and archaeometrical data are combined, developing new interdisciplinary techniques for innovative archaeological interpretation of glass trade in the Hellenistic-Roman world."