Current mining operators in the Athabasca oil sands deposit of Alberta, Canada have made commitments to zero discharge of oil sands process-affected waste materials (OSPM) from the mine site and rehabilitation of mined lands to a pre-mining state. As part of aquatic reclamation efforts, experimental test sites that contain a range of OSPM (solid and liquid components) were constructed to monitor the evolution and viability of aquatic habitats used as disposal sinks for OSPM produced by mining activities. In the present study, stable isotopes of carbon, nitrogen and sulphur were used to gauge some of the potential effects of OSPM site construction methods on aquatic food webs. Carbon and nitrogen isotopic signatures of sediment, dissolved inorganic carbon, dissolved organic carbon, particulate organic matter, periphytic material, plants, plankton, aquatic invertebrates and fish were used to assess differences related to the naphthenic acid (NA) concentration in OSPM and reference sites. For statistical analyses, sites were grouped into low (0 to 4 mg/L), medium (4 to 15 mg/L) and high (> 15 mg/L) NA concentrations. There were no significant differences in food web area or food web length among the low, medium and high NA concentration sites. In most cases, sample carbon isotope analyses of low, medium and high NA concentration sites were not significantly different, suggesting food web carbon sources did not include significant contributions from OSPM materials at OSPM sites. Significant differences, however, were found in the sample nitrogen isotope signatures between low, medium and high NA concentration sites. Ammonia from OSPM is suggested to be the main contributor to &delta;¹⁵N enrichment. <br /><br /> To determine the potential effects of site construction and OSPM within experimental test sites, carbon and sulphur stable isotopes of water, plankton, aquatic invertebrates and fish were analyzed. With the exception of <em>Chaoborus</em> and <em>Haliplus</em>, all carbon isotope signatures were not significantly different in constructed and reference sites. Also with the exception of <em>Haliplus</em>, sulphur isotope values for aquatic organisms from constructed and reference sites were significantly different. Aquatic organisms and water samples from constructed sites built in, or close, to the boundary of Kcw clays typically had &delta;³⁴S < 0 ?. Coinciding with depleted &delta;³⁴S signatures found in these aquatic systems were elevated sulphate concentrations. The waters at experimental test sites are in direct contact with the soil materials that facilitate the accumulation of sulphates as a result of the oxidation of substrate sulphide minerals. In general the results of the study suggest that aquatic food web structure and function do not change with the introduction of OSPM. Shifts in isotopic signatures suggestive of changes in food web structure, however, do occur when site construction exposes Kcw clays in the substrate.

Current mining operators in the Athabasca oil sands deposit of Alberta, Canada have made commitments to zero discharge of oil sands process-affected waste materials (OSPM) from the mine site and rehabilitation of mined lands to a pre-mining state. As part of aquatic reclamation efforts, experimental test sites that contain a range of OSPM (solid and liquid components) were constructed to monitor the evolution and viability of aquatic habitats used as disposal sinks for OSPM produced by mining activities. In the present study, stable isotopes of carbon, nitrogen and sulphur were used to gauge some of the potential effects of OSPM site construction methods on aquatic food webs. Carbon and nitrogen isotopic signatures of sediment, dissolved inorganic carbon, dissolved organic carbon, particulate organic matter, periphytic material, plants, plankton, aquatic invertebrates and fish were used to assess differences related to the naphthenic acid (NA) concentration in OSPM and reference sites. For statistical analyses, sites were grouped into low (0 to 4 mg/L), medium (4 to 15 mg/L) and high (> 15 mg/L) NA concentrations. There were no significant differences in food web area or food web length among the low, medium and high NA concentration sites. In most cases, sample carbon isotope analyses of low, medium and high NA concentration sites were not significantly different, suggesting food web carbon sources did not include significant contributions from OSPM materials at OSPM sites. Significant differences, however, were found in the sample nitrogen isotope signatures between low, medium and high NA concentration sites. Ammonia from OSPM is suggested to be the main contributor to &delta;¹⁵N enrichment. <br /><br /> To determine the potential effects of site construction and OSPM within experimental test sites, carbon and sulphur stable isotopes of water, plankton, aquatic invertebrates and fish were analyzed. With the exception of <em>Chaoborus</em> and <em>Haliplus</em>, all carbon isotope signatures were not significantly different in constructed and reference sites. Also with the exception of <em>Haliplus</em>, sulphur isotope values for aquatic organisms from constructed and reference sites were significantly different. Aquatic organisms and water samples from constructed sites built in, or close, to the boundary of Kcw clays typically had &delta;³⁴S < 0 ?. Coinciding with depleted &delta;³⁴S signatures found in these aquatic systems were elevated sulphate concentrations. The waters at experimental test sites are in direct contact with the soil materials that facilitate the accumulation of sulphates as a result of the oxidation of substrate sulphide minerals. In general the results of the study suggest that aquatic food web structure and function do not change with the introduction of OSPM. Shifts in isotopic signatures suggestive of changes in food web structure, however, do occur when site construction exposes Kcw clays in the substrate.

This study compared traditional community analysis with stable-isotope trophic analysis to define process-based trophic elements of community structure in the eastern Gulf of Mexico, and developed a predictive capability regarding changes to fish community structure that would be expected from increasing eutrophication. Specifically, it used an existing trawl survey program (SEAMAP) to compare invertebrate herbivore (sponge and sea urchin) isotopes with groundfish isotopes, and then compared the resulting spatial patterns with spatial variation in community structure, as identified by cluster analysis. The comparison was applied to seven NMFS survey zones that extended offshore from the Caloosahatchee River, FL northwest to Mobile Bay, AL. Isotopic patterns were consistent with the presence of an oligotrophic-eutrophic spatial gradient in this region. δ15N values increased in the northwestward direction in herbivores and in each of the 17 fish species examined. In the southern NMFS survey zones, δ13C was elevated in shallow depths for individual fish species, but not in herbivores, indicating a higher proportion of benthically derived biomass contributed to the biomass of fish in the shallow parts of the southern NMFS zones. Fish community analysis using SIMPROF created a similar pattern, with distinct nearshore and offshore communities and also a northwesterly community transition. Among the 17 fish species, five appeared to have obligate dependence on either benthic or planktonic basal resources, while twelve species appeared to be have facultative relationships. Impairment of current water-quality (nutrients, turbidity, light transmission, chlorophyll a) is expected to lead to reductions in the abundance of both obligate and facultative benthic-dependent fishes.

No description available.

Orientador: Gustavo Quevedo Romero / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-18T12:38:24Z (GMT). No. of bitstreams: 1 Goncalves_AnaZangirolame_M.pdf: 2619238 bytes, checksum: 7829d9724c33ae79b0974c3db972f845 (MD5) Previous issue date: 2011 / Resumo: Inúmeros organismos vivem associados a plantas da família Bromeliaceae e rejeitos derivados desses organismos (e.g., fezes e detritos vegetais) podem contribuir para a nutrição das bromélias. A aranha Psecas chapoda (Salticidae) habita Bromelia balansae, Ananas comosus e Aechmea distichantha (Bromelioideae) em uma grande extensão geográfica. Dependendo da estrutura da roseta e dos tricomas absorventes, estas bromélias podem absorver mais ou menos nitrogênio derivado da aranha. A obtenção de nitrogênio pode variar de acordo com o período do ano (e.g., seco vs. chuvoso) e também devido à presença de microorganismos associados às folhas das bromélias. No presente estudo utilizamos métodos isotópicos e fisiológicos para responder as seguintes questões: (1) a aranha contribui para a nutrição e crescimento de B. balansae, An. comosus e Ae. distichantha? (2) quais respostas fisiológicas (i.e., concentrações de clorofilas, carotenóides e proteínas solúveis) as plantas apresentam por ganharem nitrogênio derivado da aranha? (3) existe variação sazonal na absorção de nitrogênio proveniente das aranhas? (4) as bactérias associadas à filosfera de B. balansae facilitam a absorção de nutrientes por estas plantas? Nossos resultados mostraram que P. chapoda favorece nutricionalmente suas três bromélias hospedeiras. Entretanto, nossos resultados indicam que o mutualismo entre aranhas e bromélias é sazonalmente restrito gerando resultados condicionais. A variação interespecífica na obtenção de nitrogênio ocorreu provavelmente devido às diferentes performances e rotas fotossintéticas de cada espécie. Enquanto B. balansae parece utilizar nitrogênio para crescimento, Ae. distichantha aparentemente acumula nitrogênio para condições de estresse nutricional. Adicionalmente, mostramos que plantas com densidade natural de bactérias acumularam 57% mais proteínas solúveis e cresceram 13% mais do que as bromélias que tiveram a abundância de bactérias reduzidas com antibióticos. Estes resultados sugerem pela primeira vez que bactérias aceleram a ciclagem de nutrientes na filosfera e podem favorecer nutricionalmente estas plantas / Abstract: Many organisms live associated with Bromeliaceae plants and materials derived from these organisms (e.g., faeces and plant debris) may contribute to bromeliad nutrition. The spider Psecas chapoda (Salticidae) lives in Bromelia balansae, Ananas comosus and Aechmea distichantha (Bromelioideae) in a large geographic extent. Depending on the structure of the rosette and trichomes, these bromeliads may absorb more or less nitrogen derived from spiders. The acquisition of nitrogen may vary according to the seasons (e.g., dry vs. wet) and also due to the presence of microorganisms associated with bromeliad leaves. In this study we used physiological and isotopic methods to answer the following questions: (1) Do spiders contribute to the nutrition and growth of B. balansae, An. comosus and Ae. distichantha? (2) Which physiological responses (i.e., chlorophylls, carotenoids and soluble protein concentrations) the plants have by receiving nitrogen from spiders? (3) Is there seasonal variation in the absorption of nitrogen from spiders? (4) Do bacteria associated with B. balansae phyllosphere facilitate nutrient absorption by these plants? Our results showed that P. chapoda nutritionally improve their three host plants. However, our results indicate that this mutualism is seasonally restricted generating conditional outcomes. The interespecific variation in nitrogen acquisition occurred probably due to different performances and photosynthetic routes of each plant species. While B. balansae appear to use nitrogen for growth, Ae. distichantha apparently accumulate nitrogen for nutritional stress conditions. Additionally, we showed that plants with natural density of bacteria accumulated 57% more soluble proteins and grew 13% more than bromeliads that had their abundance of bacteria reduced with antibiotics. These results suggest for the first time that bacteria accelerate nutrient cycling in the phyllosphere and may nutritionally favor these plants / Mestrado / Ecologia / Mestre em Ecologia

Sampling methods for dentine and bone collagen have been evolving for several decades. Incremental dentine collagen sampling and bone collagen sampling have been limited by the available technology throughout that time. As the technology for isotope ratio mass spectrometry analysis improves, the sampling methods should improve as well. This research focused on developing a new incremental dentine collagen sampling method and bone collagen microsampling method for stable isotope analysis. This research aimed to increase the temporal resolution of incremental dentine collagen sampling and provided sequential collagen sampling from bone collagen for stable carbon and nitrogen isotope analysis while limiting the destructive nature of bioarchaeological analysis. It was determined that the temporal resolution for incremental analysis could be reduced to approximate three months, opposed to the nine months found in other sampling methods. It was also determined that detailed isotopic data could be obtained from bone collagen when sampling the microstructures. The increased amount of isotopic data from the bone collagen was an improvement on the commonly used bulk collagen sampling. This research can be utilised to answer several of the questions that archaeologists have been asking about past populations. Isotopic analysis using the methods developed in the research can provide a more detailed observation of the diet and health of past populations. In addition, the developed methods for bone and dentine collagen reduced the amount of tissue subjected to destructive analysis.

Ammonium has been detected in and around several epithermal Au-Ag deposits, including those in Nevada, Japan, Argentina, Mexico, and New Zealand, using short-wave infrared (SWIR) reflectance spectroscopy. This study examined the distribution and occurrence of ammonium in three epithermal low-sulfidation vein-type deposits in the Hauraki goldfield of New Zealand: Martha (>6.7Moz Au, >42.1Moz Ag), Favona (>0.6Moz Au, >2.36Moz Ag), and the recently discovered Wharekirauponga (WKP; 0.42Moz Au, 0.8Moz Ag) deposit. The Martha and Favona auriferous quartz-adularia veins are hosted by late Miocene to Pliocene andesite, whereas auriferous veins at WKP are hosted by late Miocene to Pliocene rhyolite. The wallrock of all three deposits is altered to form quartz, illite, smectite, adularia, chlorite, and pyrite +/- kaolinite. Ammonium contents are enriched (>137 ppm) in wallrock samples from all three deposits and low (<94 ppm) in vein samples. Ammonium contents are higher at Favona (<10,675 ppm) than at Martha (<192 ppm) and WKP (<2,783 ppm). Leaching experiments using a 2N KCl solution show that most ammonium is in mineral structures (>90% at Favona, >80% at Martha, >70% at WKP). There is a positive correlation of ammonium contents with LOI (0.6 – 16.3 wt%) and with K2O (1.3 – 8.0 wt%) in all samples which suggest a hydrous potassium mineral as the major host of the ammonium. This is supported by the SWIR data obtained by previous workers of these samples where they show an absorption at ~1410 nm due to OH. At Favona, samples with high ammonium (>990 ppm) are reported to have significant absorption at ~2000 nm and ~2100 nm in the SWIR spectra likely due to ammonium. High ammonium contents (990 – 10,675 ppm) are found in rocks less than ~100m from the Favona vein which occur within an ammonium-bearing zone identified by previous workers based on SWIR. Samples outside of this zone contain low ammonium (107 – 301 ppm) with the smectite altered samples being the lowest. Ammonium contents within the hangingwall (1,827 – 10,675 ppm) of the Favona vein tend to be higher than in the footwall (990 – 4,301 ppm) and are highest within the most intensely illite altered rocks. At WKP, the intensely adularia +/- minor illite altered samples within 100m of the main East-Graben (EG) vein contain low ammonium (<200 ppm). The intensely illite altered samples away from the EG vein (>100m) have higher ammonium contents (200 – 800 ppm). This relationship of high ammonium contents to high illite abundance confirms illite as the major host of ammonium in these deposits. δ15N values for all samples (n=54) including near and far from auriferous veins range from +0.5 to +7.9 ‰, suggesting the derivation of most of the ammonium from the Jurassic greywacke basement or sediments intercalated within the volcanic rocks.

This study investigated stable-isotope ratio evidence of weaning for the late Anglo-Saxon population of Raunds Furnells, Northamptonshire, UK. delta(15)N and delta(13)C values in rib collagen were obtained for individuals of different ages to assess the weaning age of infants within the population. A peak in delta(15) N values at about 2-year-old, followed by a decline in delta(15) N values until age three, indicates a change in diet at that age. This change in nitrogen isotope ratios corresponds with the mortality profile from the site, as well as with archaeological and documentary evidence on attitudes towards juveniles in the Anglo-Saxon period. The pattern of delta(13) C values was less clear. Comparison of the predicted age of weaning to published data from sites dating from the Iron Age to the 19th century in Britain reveals a pattern of changing weaning practices over time, with increasingly earlier commencement and shorter periods of complementary feeding in more recent periods. Such a change has implications for the interpretation of socioeconomic changes during this period of British history, since earlier weaning is associated with decreased birth spacing, and could thus have contributed to population growth.

Increasing human populations and activities in coastal areas have led to high nutrient loading and estuarine ecosystem decline. Natural hydrological patterns in South Florida have been drastically altered by changes in water management and land use practices. As a result Florida Bay has experienced a series of negative ecosystem effects including hypersalinity events, degradation of water quality, and harmful algal blooms and declines in upper trophic level populations. To remediate ecosystem decline in Florida's coastal ecosystems, the Comprehensive Everglades Restoration Plan proposes to restore a more natural hydrologic flow in the Everglades. It is expected hydrologic restoration efforts will change the amount, sources and ratios of dissolved nutrients (organic and inorganic) delivered to the bay potentially inducing an ecosystem response of changing structure and function in both planktic and benthic habitats. Identifying biogeochemical linkages between external nutrient inputs from the Everglades and internal cycling processes of Florida Bay is critical to understanding the effects of hydrological restoration and changing nutrient regimes on Florida Bay. A nitrogen (δ15N) and carbon (δ13C ) stable isotopic approach affords an effective means of assessing the fate of varying nutrient sources and delineating the dominant biogeochemical processes governing nutrient cycling in the bay. This study's main goals were to use stable isotopic analyses of C and N in dissolved and particulate materials to determine spatial and seasonal relationships between Everglades nutrient sources and their biological sinks in Florida Bay, examine the biogeochemical relationships among inorganic and organic components of the water column and benthos in Florida Bay, and assess future ecological response to changing nutrient inputs resulting from restoration efforts. A large east to west gradient from more enriched to more depleted δ15N values was noted in both dissolved nitrogen pools and organic components of the bay. This trend indicates that there are differing nutrient sources and biogeochemical processes influencing the various regions of the bay. Isotopic similarity of the dissolved nitrogen pools from the Everglades and particulate organic matter in the bay points to a strong relationship between both ecosystems. Everglades nutrient inputs delivered to the bay in the wet season directly influence ecological responses in the bay, in some cases increases in algal biomass. Seasonality also influences nitrogen transformations in the dissolved nitrogen pools and the sediments. During dry periods when there is little or no hydrologic flow from the Everglades into the bay, denitrification is a major process affecting nitrogen cycling in the eastern and central regions of the bay. During the wet periods, denitrification becomes suppressed and dissimilatory nitrate reduction (DNRA) is favored. Increased hydrologic flow brings fresh organic matter that fuels DNRA. There was a consistent spatial pattern from more depleted to more enriched δ13C values, onshore to offshore relative to the mainland which indicates strong terrestrial influence on Florida Bay sites along the mangrove boundary with the Everglades. Particulate organic matter exhibited a shift to more enriched δ13C values during the wet season which reflects an increase in algal biomass. A shift to more depleted δ13C values of DOM indicated increased terrestrial influence from the Everglades during the wet season. The approach undertaken in this study identifies a strong linkage between nutrient inputs from the Everglades and biogeochemical processes in the bay. These findings underscore the need to consider the impact of both allochtonous nutrient inputs and the dominant processes governing cycling in the bay when making management decisions that continue to refine hydrologic restoration plans.

No description available.