During the course of this research an instrument utilising combustion as a means of gas extraction capable of N, e, Ar and He analysis has been developed and the entire analytical procedure has been automated. N and e isotopic analysis has been performed on eclogitic and peridotitic diamonds (mainly from Yakutian kimberlites and the Roberts Victor kimberlite pipe). Diamonds with unusual (light and heavy relative to the peak of ol3e distribution of mantle diamonds) carbon isotopic signatures were considered for the research so that diamonds in the range of δ¹³C from -30‰ to + 2.8‰ were characterised for δ¹⁵N. The results together with data obtained previously by the others define fields for eclogitic and peridotitic diamonds on a plot of δ¹⁵N vs. δ¹³C. The model of mantle nitrogen and carbon evolution is discussed. A comprehensive comparison between carbonado and other known forms of microcrystalline diamond (framesites and shock diamonds) has been made for a number of parameters: N and e isotopic composition and N content; 4He content; morphology of the inner structure of diamond aggregates. It can be concluded that carbonado is generally similar to frame sites and all facts known about carbonado can be explained on the grounds of common mantle origin involving subducted carbon and nitrogen. Since extremely high 4He concentrations are encountered in carbonado this parameter is considered to be the most singular feature of this diamond variety and the radial distribution of 4He in single diamond crystals has been studied. A 4He content comparable with that in carbonado was found in the 30 J.lm skin of diamond crystals (up to 1.4 x 10⁻²) suggesting that carbonado could acquire high 4He concentration in the same geological processes as single diamond crystals and making carbonado indistinguishable from mantle diamonds in terms of He content. An additional result of the investigation is that the maximum of 4He diffusion coefficient for diamond at mantle P,T conditions can be estimated (≈4x10⁻²¹ ) from the 4He zoning identified in the interior of a diamond crystal from the Finsch kimberlite. A number of diamonds of impact origin from Popigai crater and Ebeliakh river placer deposits were studied for N, C and Ar isotopic compositions. It was concluded that diamonds from these two localities have resulted from separate impact events and that diamond aggregates studied are most probably consist of a mixture of different Ar and N carriers (e.g. two types of diamond grains).

Arsenic contamination of circum-Himalayan groundwater is leading to one of the greatest humanitarian disasters of modern times, poisoning at least 70 million people who are mostly poor and rural. The groundwater is hosted in Holocene aquifers consisting of Himalayan sediments deposited by the great Asian rivers in deltaic environments. Arsenic is released when organic material (OM) reacts with the iron-oxide minerals co-deposited in the sediments onto which arsenic is adsorbed. The source of OM is one of the most important questions facing researchers and policy makers. There are generally accepted to be three potential sources of OM: 1) sedimentary bound OM (SOM) co-deposited with sediments; 2) thermally mature petroleum upwelled from reservoirs below the aquifers; 3) dissolved organic carbon (DOC) some of which might be drawn in to the aquifer through modern pumping and irrigation. In this thesis the nature of organic material in the aquifer is researched and the processes and timescales which lead to arsenic release are studied. Here evidence for a new conceptual model of arsenic release is presented. Isotopic tracing combined with a new geochemical model and organic geochemical techniques, shows that OM driving arsenic release pre-dates agriculture in the region and was from natural grasslands in the early Holocene. The geochemical model utilises strontium isotopes to correct the radiocarbon age of dissolved inorganic carbon (DIC) to find only the age and isotopic signature of DIC from oxidation of organic material. This shows that DIC from oxidation of OM was from the early Holocene and had an isotopic signature consistent with the early Holocene SOM in this region. A study of the sediments in the region built upon a geomorphological history shows that the most oxidised SOM is from early Holocene sediments. Thus both techniques separately indicate that pre-agricultural organic material drove arsenic release. This conceptual model however reveals the "arsenic sand paradox", because whilst release is from early Holocene clays, today highest concentrations of arsenic are in younger sands. Explaining this paradox is the most important next step leading on from this research.

In estuarine and other aquatic systems, it is possible for water to transport locally produced carbon (food) across habitat boundaries, and provide nutrition for animals remote from the carbon source. In estuarine and marine systems, early work examining the movement of carbon from saltmarsh habitats in the USA suggested that carbon may move large distances from inshore to offshore environments. Upon closer examination, however, evidence did not support this paradigm of large-scale carbon movement, referred to as the outwelling hypothesis, in some estuaries. Physical characteristics of estuaries in which large-scale carbon movement did not occur, such as restricted access to the sea, were proposed as a possible explanation, and for these estuaries, movement of carbon among estuarine habitats was considered more likely. A mosaic of saltmarsh and mangrove habitats dominate the subtropical barrier estuary of southern Moreton Bay, Queensland, but there have been no studies that examine the movement of carbon among habitats within this system. Previous studies that examine the movement of carbon have mostly been done in saltmarshes in the northern hemisphere or in tropical mangrove systems. Different vegetation and tidal regimes in temperate marshes of the northern hemisphere preclude generalisations of carbon movement to tropical and subtropical systems. Our understanding of carbon movement in tropical systems may extend to subtropical waters, but the saltmarsh-mangrove mosaic in the subtropics distinguishes them from their tropical counterparts. The mosaic of saltmarsh and mangrove habitats among the barrier islands of southern Moreton Bay thus provide a unique opportunity to examine the small-scale movement of carbon among adjacent habitats in a subtropical system. Stable isotopes of carbon have been used successfully to trace the transfer of carbon from autotrophs to consumers at a range of spatial scales. This method is able to distinguish among carbon sources where autotrophs have different ratios of 13C/12C, and consumers take on the ratio of their food source. The success of stable isotopes in clarifying food web processes, however, depends on isotope ratios changing in predictable ways as elements are processed. As isotope ratios may be influenced by changes in productivity, and differences in nutrient source, they may vary across small and large spatial scales that may confound interpretation of food web processes. In this study I measured small and large-scale spatial variability of three estuarine autotrophs (the saltmarsh grass, Sporobolus virginicus, the seagrass Zostera capricorni and the algal community epiphytic on Z. capricorni) and showed the small-scale spatial variability to be negligible and insufficient to preclude the use of carbon and nitrogen isotopes in food web studies. Large-scale variability was more pronounced and may be useful for spatial correlation of food webs for more mobile species. The small-scale homogeneity and clearly distinguished isotope ratios of the dominant autotrophs in adjacent saltmarsh and mangrove habitats in southeast Queensland are therefore ideally suited to the study of small-scale carbon movement between adjacent habitats. Carbon isotopes of estuarine invertebrates were used to estimate the movement of particulate carbon between adjacent saltmarsh and mangroves at the tens-of-metre scale. Carbon isotope values of two crab species (Parasesarma erythrodactyla and Australoplax tridentata) and two snail species (Salinator solida and Ophicardelus quoyi) in saltmarsh closely match those of the saltmarsh grass, and suggest that the movement and assimilation of carbon occurs at a scale much smaller than has previously been examined. In mangroves, the results of this study indicate that microphytobenthos with some contribution of mangrove carbon is the most likely food source for P. erythrodactyla and A. tridentata, although contribution of carbon from saltmarsh is also possible. Under this latter scenario, carbon movement in mangroves would be considered to occur at a scale larger than that in saltmarsh habitat. A study that examined the movement and assimilation of carbon by crabs and an estuarine slug (Onchidina australis) at a finer resolution (i.e. metres) supported the original findings and indicated that the movement and assimilation of carbon occurs 5 - 8 m either side of the saltmarsh-mangrove interface. At this small-scale, the movement and subsequent foraging of crabs among habitats, the movement of particulate carbon among habitats, or a combination of crab and particulate carbon movement are three alternative models that provide plausible explanations for the pattern in carbon isotope values of crabs. Crab movement among these habitats was measured using an array of pitfall traps perpendicular to the saltmarsh-mangrove interface. To test for carbon movement, samples of detritus were collected at 2 m intervals across this same interface and the carbon isotopes analysed. For the majority of crabs (up to 90% for both species), movement up or down the shore was less than 1 m from the place of initial capture. Thus, crab movement cannot explain the trend in carbon isotope values of crabs. The pattern in detrital isotope values was similar to that of crabs and indicates that the movement of particulate carbon across the saltmarsh-mangrove interface is the most likely explanation for crab isotope ratios. Sources of carbon for estuarine invertebrates can also depend on the size of the saltmarsh patches. Examination of the movement and assimilation of carbon by crabs in saltmarsh patches of different sizes adjacent to mangroves indicates that saltmarshes less than 0.3 ha in area are subsidised by the import of allochthonous carbon, most likely from mangroves. These findings contribute substantially to our understanding of the food web value of estuarine habitats and provide an important link between landscape and food web ecology. They also have important implications for determining the conservation value of estuarine habitats with respect to their functional (food web) value. The scale-dependent sampling used in this thesis also provides important evidence for the fine-scale movement of estuarine carbon that has not previously been examined.

As a result of the legacy of industrial contamination over the last century, areas of sediment deposition in the St. Lawrence River at Cornwall, ON, contain high concentrations of mercury (Hg). The popular sport-fish species, yellow perch (Perca flavescens) and walleye (Sander vitreus) have been found to contain mercury concentrations exceeding Ontario Ministry of Environment consumption guidelines. Interestingly, a paradox exists between two contaminated sites – despite elevated sediment Hg concentrations at Zone 2, fish from Zone 1 contain higher Hg concentrations. Further research has indicated that these patterns of Hg were not attributed to growth rate, condition factor, diet composition, or trophic position of yellow perch. Rather, Hg concentrations in yellow perch may be described by the heterogeneity of prey contamination and fish bioenergetics. As a result of the paradox between total Hg (THg) concentrations in sediments and biota between two contaminated sites, it was necessary to examine the benthic invertebrate community and how it may transfer Hg from sediments to yellow perch. This apparent paradox now extends to all prey items, since prey items from the stomach contents of yellow perch caught in Zone 1 were significantly more contaminated than those of Zone 2. Use of δ15N and δ13C, measures of trophic position and energy source, respectively, indicated that prey selection, but not food chain length, may also be an important factor in explaining the variation in Hg burdens in yellow perch. Small-scale patterns of biomagnification, as shown by a comparison of δ15N and logTHg, indicated that the rates of biomagnification were similar among zones, but the amount of THg present at the base of the food web was twice as high at Zone 1 as at other contaminated sites. Overall, the relative importance of vertical and horizontal food web structure changed spatially and temporally, highly influencing THg concentrations of prey items and yellow perch. / Thesis (Master, Biology) -- Queen's University, 2007-08-02 08:02:40.26

No / Dietary ecology is one key to understanding the biology, lifeways, and evolutionary pathways of many animals. Determining the diets of long-extinct hominins, however, is a considerable challenge. Although archaeological evidence forms a pillar of our understand-ing of diet and subsistence in the more recent past, for early hominins, the most direct evidence is to be found inthe fossils themselves. Here we review the suite of emerging biochemical paleodietary tools based on stable isotopeand trace element archives within fossil calcified tissues.We critically assess their contribution to advancing our understanding of australopith, early Homo, and Neander-thal diets within the broader context of non-biogeochemical techniques for dietary reconstruction, such as mor-phology and dental microwear analysis. The most signifi-cant outcomes to date are the demonstration of hightrophic-level diets among Neanderthals and Late Pleistocene modern humans in Glacial Europe, and the persis-tent inclusion of C4 grass-related foods in the diets of Plio¿Pleistocene hominins in South Africa. Such studies clearly show the promise of biogeochemical techniques for testing hypotheses about the diets of early hominins.Nevertheless, we argue that more contextual data from modern ecosystem and experimental studies are needed if we are to fully realize their potential.

Revised chronologies from Moroccan cave sites have raised questions concerning the timing of changes in human cultural behaviour in relation to past climate shifts. However, many of the inferences about past moisture regimes are based on external records. Therefore, this thesis aimed to develop a palaeoclimate record using oxygen and carbon isotope values (d18O and d13C) in Gerbillinae (gerbil) teeth from two Late Pleistocene cave sites, El Harhoura 2 and Taforalt, in Morocco. Since small mammals are not commonly used to construct proxy climate records, a modern isotope study was undertaken in northwestern Africa to understand the influences on the stable isotope composition of small mammal tissues in semi-arid and arid settings. The results from the modern study show that d18O composition of gerbil teeth is strongly correlated with mean annual precipitation (MAP), and therefore in arid settings reflects moisture availability. Predictably, the d13C values of the gerbil teeth reflected C3 and C4 dietary inputs, but arid and mesic sites could not be distinguished because of the high variability displayed in d13C. The d18O isotope-based MAP reconstructions suggest that the Mediterranean coastal region of North Africa did not experience hyper-arid conditions during the Late Pleistocene. The d13C values of the gerbil teeth show that C3 vegetation dominated in the Late Pleistocene, but there was a small amount C4 vegetation present at Taforalt. This indicates that small mammals are extremely sensitive to discreet shifts in past vegetation cover. Both the modern and archaeological studies demonstrated that the isotope values of molars and incisors differed. The results indicate that tooth choice is an important consideration for applications as proxy Quaternary records, but also highlights a new potential means to distinguish seasonal contexts. Comparisons of proxy climate records and cultural sequences at Taforalt and El Harhoura 2 show that Middle Stone Age occupations of both sites occurred during relatively humid and arid climate phases. The transition to the Later Stone Age appears to have taken place during a period of increased aridity, hinting that this cultural transition may be related to changing environmental conditions.

The arid interior of South Africa lacks long, continuous and well-dated climate and environmental proxy records that can be compared with cultural sequences and with broader global climate records. This thesis develops the first substantial terrestrial environmental sequence for the interior of southern Africa at the site of Wonderwerk Cave, spanning two million years of prehistory. Changes in vegetation and humidity over time were investigated by means of carbon and oxygen stable isotope analysis on fossil herbivore enamel and ostrich eggshell, creating two independent proxy datasets. The Holocene record was used as a baseline for comparing the Pleistocene sequence, but required chronological tightening. Therefore, nine new radiocarbon dates were obtained, and calibrated and modelled with existing dates to provide a firmer chronology. The ostrich eggshell isotope record suggests arid but variable conditions, with distinct phases of increased humidity in the Early Pleistocene and mid-Holocene. Enamel stable isotope results show clear differences in local resource availability between the Early and Mid-Pleistocene, and then between the Pleistocene and Holocene, with an overall trend of increasing aridity. In particular, the onset of dietary specialisation in grazers at 0.8Ma is linked to expanding C4 grasslands. Aridity was not the driver behind the increase in C4 grasses, but changing pCO2 levels at the Mid Pleistocene transition were identified as a possible key factor. The presence of C3 and C4 grasses in the Early Pleistocene, when compared to the domination of C4 grasses today, was fostered by reduced rainfall seasonality. Regional independent developments have to be considered, as other regions in South and East Africa show C4 dominated diets in herbivores at earlier times than at Wonderwerk Cave. In the Holocene, higher temporal resolution indicates phases of environmental change coinciding with changes in the cultural record.

This diploma thesis deals with a reconstruction of the Germanic tribe of the Lombards' diet found at Kyjov burial site dated back to the Migration Period (5th - 6th century A.D.) as well as a research of their living conditions. The principal aim is a description of this population diet and its comparison to the other populations within this period and the Early Middle Ages era. The diet was examined by considering of carbon (δ13 C) and nitrogen (δ15 N) stable isotopes analysis received and evaluated from a group of 60 adult individuals (30 men and 30 females). In regard to the interpretation of the isotopes values, the stable isotopes C and N were present in some animal species (N=19). Apart from the above mentioned, several significant health indicators were chosen for evaluation which indirectly show health condition and quality of living conditions of the examined group. These health indicators were evaluated in relation to the diet. The results of this study indicate that the diet of Lombards' population was based on C3 plants and animal proteins, which is similar to the other localities in the time of the Migration Period. It shows a difference, namely in consumption of millet, providing that the Lombards to the Great Moravian's localities are compared. The millet seemed to be common part of...

A região costeira do Brasil é historicamente impactada por atividades antrópicas, que liberam contaminantes, como os metais pesados. Nos estuários de Paranaguá (PR), Cananéia e Santos (SP), tais atividades estão presentes em diferentes níveis. Neste estudo foram investigadas as concentrações de arsênio, cádmio, chumbo, cobre, cromo, níquel, selênio, zinco e mercúrio, além de isótopos estáveis de carbono e nitrogênio, em sedimentos, fragmentos vegetais e organismos marinhos, como invertebrados bentônicos, peixes bentívoros e mamíferos marinhos, coletados nos três estuários. As amostragens foram realizadas em 2015, sendo as análises de isótopos realizadas por EA-IRMS e as análises de metais pesados realizadas por ICP OES-VGA e ICP-MS. As razões isotópicas permitiram a distinção entre fontes de matéria orgânica e nível trófico. Exemplares da ictiofauna e de cetáceos analisados não apresentaram distinção entre os níveis tróficos 3 e 4, indicando uma dieta generalista para estes animais e potencial compartilhamento de nicho trófico. Os metais apresentaram maiores concentrações nos sedimentos do estuário de Santos, coincidindo com o local com maior intensidade de atividades antrópicas. Comparando os estuários há maior acumulação de: Cr, Cu, Zn e Hg em Paranaguá, As e Pb em Cananéia, e Cd, Ni e Se em Santos, resultados justificados por atividades antrópicas, fontes naturais e características geoquímicas de cada região. A tendência de biomagnificação de Se foi observada nas teias tróficas de todos os estuários, e de Zn e Hg nas teias de Paranaguá e Cananéia. Entretanto, As, Cr, Cu, Ni e Pb demostraram tendência a biodiluição nas teias tróficas estudadas, com maior bioacumulação em invertebrados bentônicos. Portanto, este estudo traz um panorama atual da distribuição espacial e trófica de metais pesados nos estuários, colaborando com o monitoramento e ações de gestão costeira. / The coastal region of Brazil is historically impacted by anthropic activities, which release contaminants such as heavy metals. In the estuaries of Paranaguá (PR), Cananéia and Santos (SP), these activities are present in different levels. In the present study, concentrations of arsenic, cadmium, lead, copper, chromium, nickel, selenium, zinc and mercury were investigated, as well as stable carbon and nitrogen isotopes in sediments, plant fragments and marine organisms such as benthic invertebrates, benthivorous fish and marine mammals, collected in the three estuaries. Samples were collected in 2015, with isotope analysis performed by EA-IRMS and heavy metal analysis performed by ICP OES-VGA and ICP-MS. Isotopic ratios allowed the distinction between organic matter sources and trophic level. The specimens of the ichthyofauna and cetaceans analyzed did not present distinction between trophic levels 3 and 4, indicating a generalist diet for these animals and a potential sharing of trophic niche. The metals have presented higher concentrations in the sediments from Santos estuary, what coincides with the place with greater intensity of anthropic activities. Comparing the estuaries, there is more bioaccumulation of Cr, Cu, Zn and Hg in Paranaguá, As and Pb in Cananéia, and Cd, Ni and Se in Santos; results which are justified by anthropic activities, natural sources and geochemical characteristics of each region. A biomagnification tendency of Se was observed in the trophic webs of all estuaries, and Zn and Hg in the Paranaguá\'s and Cananéia\'s webs. However, As, Cr, Cu, Ni and Pb displayed a tendency to biodilution in the studied trophic webs; with a higher bioaccumulation in benthic invertebrates. Therefore this study provides a current overview of the spatial and trophic distribution of heavy metals in the estuaries. Thus, it is collaborating with the monitoring and actions of coastal management.

A região costeira do Brasil é historicamente impactada por atividades antrópicas, que liberam contaminantes, como os metais pesados. Nos estuários de Paranaguá (PR), Cananéia e Santos (SP), tais atividades estão presentes em diferentes níveis. Neste estudo foram investigadas as concentrações de arsênio, cádmio, chumbo, cobre, cromo, níquel, selênio, zinco e mercúrio, além de isótopos estáveis de carbono e nitrogênio, em sedimentos, fragmentos vegetais e organismos marinhos, como invertebrados bentônicos, peixes bentívoros e mamíferos marinhos, coletados nos três estuários. As amostragens foram realizadas em 2015, sendo as análises de isótopos realizadas por EA-IRMS e as análises de metais pesados realizadas por ICP OES-VGA e ICP-MS. As razões isotópicas permitiram a distinção entre fontes de matéria orgânica e nível trófico. Exemplares da ictiofauna e de cetáceos analisados não apresentaram distinção entre os níveis tróficos 3 e 4, indicando uma dieta generalista para estes animais e potencial compartilhamento de nicho trófico. Os metais apresentaram maiores concentrações nos sedimentos do estuário de Santos, coincidindo com o local com maior intensidade de atividades antrópicas. Comparando os estuários há maior acumulação de: Cr, Cu, Zn e Hg em Paranaguá, As e Pb em Cananéia, e Cd, Ni e Se em Santos, resultados justificados por atividades antrópicas, fontes naturais e características geoquímicas de cada região. A tendência de biomagnificação de Se foi observada nas teias tróficas de todos os estuários, e de Zn e Hg nas teias de Paranaguá e Cananéia. Entretanto, As, Cr, Cu, Ni e Pb demostraram tendência a biodiluição nas teias tróficas estudadas, com maior bioacumulação em invertebrados bentônicos. Portanto, este estudo traz um panorama atual da distribuição espacial e trófica de metais pesados nos estuários, colaborando com o monitoramento e ações de gestão costeira. / The coastal region of Brazil is historically impacted by anthropic activities, which release contaminants such as heavy metals. In the estuaries of Paranaguá (PR), Cananéia and Santos (SP), these activities are present in different levels. In the present study, concentrations of arsenic, cadmium, lead, copper, chromium, nickel, selenium, zinc and mercury were investigated, as well as stable carbon and nitrogen isotopes in sediments, plant fragments and marine organisms such as benthic invertebrates, benthivorous fish and marine mammals, collected in the three estuaries. Samples were collected in 2015, with isotope analysis performed by EA-IRMS and heavy metal analysis performed by ICP OES-VGA and ICP-MS. Isotopic ratios allowed the distinction between organic matter sources and trophic level. The specimens of the ichthyofauna and cetaceans analyzed did not present distinction between trophic levels 3 and 4, indicating a generalist diet for these animals and a potential sharing of trophic niche. The metals have presented higher concentrations in the sediments from Santos estuary, what coincides with the place with greater intensity of anthropic activities. Comparing the estuaries, there is more bioaccumulation of Cr, Cu, Zn and Hg in Paranaguá, As and Pb in Cananéia, and Cd, Ni and Se in Santos; results which are justified by anthropic activities, natural sources and geochemical characteristics of each region. A biomagnification tendency of Se was observed in the trophic webs of all estuaries, and Zn and Hg in the Paranaguá\'s and Cananéia\'s webs. However, As, Cr, Cu, Ni and Pb displayed a tendency to biodilution in the studied trophic webs; with a higher bioaccumulation in benthic invertebrates. Therefore this study provides a current overview of the spatial and trophic distribution of heavy metals in the estuaries. Thus, it is collaborating with the monitoring and actions of coastal management.