The caribou (Rangifer tarandus groenlandicus) on Southampton Island, Nunavut, Canada for the years 1998-2000 and 2004, 2005, were investigated using stable isotope analysis (SIA) of carbon (d 13C) and nitrogen (d 15N). Spring signatures of rumen contents and muscle samples were correlated with standard biological measures of back fat and Riney kidney fat index. Caribou d 13C and d 15N ratios, together with detailed rumen content analysis, show that SIA data yields a time-integrated signal reflective of spatial and temporal variation in feeding ecology and as such is capable of detecting trophic interactions. Rumen content signatures provide current indication of forage selection, while muscle tissue signatures reflect bulk summer seasonal diet and in combination with rumen signatures, can help identify potential shifts in winter diet and the potential for short-term changes in caribou condition. <br /><br /> d 13C and d 15N signatures for major forage species categories were also compared to variations in rumen content and muscle signatures to investigate possible changes in forage preference. The results indicate that SIA is capable of assessing the importance of seasonal habitat use with regard to seasonal food intake. Stable isotopes analysis (SIA) was also used to investigate the effects of winter snow thickness and temperature on caribou (Rangifer tarandus), on Southampton Island. Variations found in isotope signatures of rumen content and muscle indicated that differences in winter climate conditions may affect forage selection, and impact on animal condition.

The caribou (Rangifer tarandus groenlandicus) on Southampton Island, Nunavut, Canada for the years 1998-2000 and 2004, 2005, were investigated using stable isotope analysis (SIA) of carbon (d 13C) and nitrogen (d 15N). Spring signatures of rumen contents and muscle samples were correlated with standard biological measures of back fat and Riney kidney fat index. Caribou d 13C and d 15N ratios, together with detailed rumen content analysis, show that SIA data yields a time-integrated signal reflective of spatial and temporal variation in feeding ecology and as such is capable of detecting trophic interactions. Rumen content signatures provide current indication of forage selection, while muscle tissue signatures reflect bulk summer seasonal diet and in combination with rumen signatures, can help identify potential shifts in winter diet and the potential for short-term changes in caribou condition. <br /><br /> d 13C and d 15N signatures for major forage species categories were also compared to variations in rumen content and muscle signatures to investigate possible changes in forage preference. The results indicate that SIA is capable of assessing the importance of seasonal habitat use with regard to seasonal food intake. Stable isotopes analysis (SIA) was also used to investigate the effects of winter snow thickness and temperature on caribou (Rangifer tarandus), on Southampton Island. Variations found in isotope signatures of rumen content and muscle indicated that differences in winter climate conditions may affect forage selection, and impact on animal condition.

Stable isotope (SI) ratios of carbon (δ13C) and nitrogen (δ15N) are now widely used as biomarkers in ecological studies to provide information about food web structuring. However, understanding trophic relationships using SI analysis requires not only knowledge of SI values of predator and prey, but also accurate discrimination factors (DFs), which can differ among species and by physiological state. This thesis examined three questions using captive birds from the South African Foundation for the Conservation of Coastal Birds (SANCCOB). First, the effects of ontogeny on δ13C and δ15N ratios of African penguins (Spheniscus demersus) were assessed. Blood samples were collected from penguins in four age classes (P3 chicks, blues, juveniles and adults) concurrently with their diet (sardine (Sardinops sagax) and formula). Second, to assess the influence of breeding physiology on SI ratios, the blood of ten breeding pairs of penguins was sampled over a five-month period from June to October 2016. Following laying, each pair was categorised into one of three (four for whole blood) egg production phases (initial yolk deposition, rapid yolk deposition and post-laying) and their influences on SI ratios were tested. Third, species differences in DFs were evaluated for African penguins, kelp and Hartlaub’s gulls (Larus dominicanus and L. hartlaubii), greater crested terns (Thalasseus bergii) and Cape cormorants (Phalacrocorax capensis). Flying birds were mostly fed sardine with a small but unknown amount of sardinella (Sardinella aurita), DFs were therefore estimated for a 50:50 sardine:sardinella diet, a 75:25 sardine:sardinella diet and a 100% sardine diet for each flying bird species. The DFs were assessed for the whole blood (WB), red blood cells (RBC), plasma (PL) and delipidated plasma of the penguins, and only WB for the flying birds as well as flesh, whole fish, delipidated flesh and delipidated whole fish for fish species, and for formula. Results indicated that age influenced both the δ13C and δ15N of WB, only the δ15N of RBC and the δ13C of delipidated PL. The assessment of breeding physiology yielded a significant interaction between the effects of egg production phase and sex on the δ13C of WB; females had significantly lower δ13C in the rapid yolk deposition phase than the other two phases and all males. The δ13C of PL was affected only by sex, with females having a significantly lower δ13C value than males. Neither physiological state nor sex influenced the other blood components. Differences were found among the three DFs in the non-penguin species, but not for all consumer – prey tissue combinations. There were also significant differences among species with a DF calculated from a diet with the most probable prey proportions eaten. Depending on the combination of consumer and prey tissue used to calculate the DF, a different conclusion regarding trophic information can be reached. A literature review updated with the present data showed that no general pattern or grouping of similar species with regards to DF values could be drawn, highlighting the importance of determining species- and tissue-specific DFs. Thus age, egg production, tissue and species all influenced the SI values of bird blood and therefore their DFs. Not all physiological conditions affect all blood components in the same way, making different components more or less sensitive to physiological influences. Though their influence is at a small enough scale that it is unlikely to hamper correct conclusion in ecological studies, it is crucial that these factors are considered when using SI analysis (SIA). When uncertainties exist for some coefficients in wild studies, SIA should therefore be combined to other dietary techniques to determine the food web structure as best as possible.

Following the argument of cultural change between the Romano-British and Anglo-Saxon periods in Britain, the purpose of this thesis is to find evidence of change in human diet and animal husbandry in the Upper Thames Valley across this boundary. Research questions are set to find differences in human diet, animal diet, and birth seasonality of herbivores at Horcott, a site showing human activity in both periods. Stable carbon and nitrogen isotope measurements on collagen from humans and livestock animals and enamel carbonate extracted from herbivores were analysed. Results showed changes in the diets of cattle, sheep/goats, pigs, and human, and birth seasonality of cattle and sheep/goats. These changes were argued to have been caused by differences in the intensity of fertilising crop fields, the amount of animal protein fed to adult pigs, the amount of non-local food in human diet, and the significance and purpose of livestock rearing and the preference of dairy products. The outcome of this thesis enhances the understanding of: a) the strategy and the amount of human effort put into crop cultivation and livestock management; b) the availability and preference of food for humans depending on the period; and c) the site-dependent differences in the extent of change in the course of transition between the Romano-British and Anglo-Saxon periods. This thesis demonstrates the importance of animal data in order to discuss human diet, and the advantage of modelling enamel carbonate sequential data when analysing worn and shortened teeth.

Stable isotope analysis is a powerful tool that can be used to describe a population’s foraging niche by identifying basal resource use, trophic feeding levels, environmental stability, seasonal ecological variation, important shifts in life history, ontogenetic shifts, intraspecific habitat use, and population dynamics. Describing these relationships in endangered marine turtle populations and their critical foraging grounds is essential for determining informed management decisions. This study systematically describes the foraging niche of hawksbills Eretmochelys imbricata, and green turtles, Chelonia mydas in Buck Island Reef National Monument, U.S. Virgin Islands, a critical habitat for nesting and foraging. It assesses the relationships within and between the species in terms of overlap, annual and seasonal variation, and life history and feeding strategies within the community. Most importantly it describes these relationships with metrics that can be used in global comparisons or to measure change in local conditions. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

Diese Arbeit leistet einen methodischen Beitrag zur Identifizierung von Umsetzungsprozessen der Stickstoffverbindungen Ammonium und Nitrat in belasteten Grundwasserleitern mittels der Analytik der Isotopenverhältnisse N-15 bzw. O-18. Es existieren bereits verschiedene Präparationsmethoden, jedoch sind diese teilweise arbeits- oder zeitaufwändig und damit mit erheblichen Kosten verbunden. Für eine breitere Anwendbarkeit in den Umweltwissenschaften wurden im Rahmen dieser Arbeit zwei vereinfachte Methoden für die N-15 bzw. O-18 Stabilisotopenanalytik von Ammonium und Nitrat in Wässern erarbeitet. Zum einen wurde eine Fällungsmethode mit Natriumtetraphenylborat für die Probenvorbereitung der N-15 Isotopenanalyse für Ammonium weiterentwickelt, getestet und validiert. Bisher existierten keine Studien zur Anwendbarkeit dieser Methode auf die Analyse ammoniumhaltiger Wasserproben. Daher wurde die Methode in dieser Arbeit für die Anwendbarkeit auf Wasserproben optimiert, insbesondere auf natürliche Grundwasserproben. Zum anderen wurde eine gängige Aufbereitungsmethode für gelöstes Nitrat weiterentwickelt. Dabei wurden die Vorbereitungs- und Arbeitszeit der Denitrifizierermethode verkürzt, ohne die Genauigkeit der Messung negativ zu beeinflussen. Zu diesem Zweck wurden zwei bestehende Varianten der Methode miteinander kombiniert und modifiziert. Als Eignungsprüfung der Methoden zur Prozessidentifikation erfolgte eine exemplarische Feldstudie. Als Modellstandort diente ein Untersuchungsgebiet im Südosten Berlins. Der Grundwasserleiter des Standortes ist u. a. durch eine massive Kontamination von Ammonium gekennzeichnet. Im Untersuchungsgebiet wurde das sogenannte BIOXWAND-Verfahren entwickelt und zur Sanierung auf den Grundwasserleiter angewandt. Dabei handelt es sich um ein in-situ-Verfahren, wobei eine direkte Injektion von Sauerstoff in den Grundwasserleiter erfolgt um Nitrifikation zu begünstigen. Für die isotopengestützte Prozessidentifikation wurden im Rahmen dieser Arbeit von 2016 bis 2019 zweimal jährlich Grundwasserproben aus dem BIOXWAND-Anstrom und dem BIOXWAND-Abstrom entnommen und mit den erarbeiteten Präparationsmethoden aufbereitet und analysiert. Zur Prozessidentifikation wurde ein analytisches Modell erstellt. Bei der vorliegenden kumulativen Dissertation handelt es sich um eine verkürzte Darstellung der Forschungsergebnisse. Die ausführlichen Ergebnisse wurden bereits in der Fachzeitschrift 'Rapid Communications in Mass Spectrometry' veröffentlicht.:VERZEICHNIS DER TABELLEN ................................................................................ 9 VERZEICHNIS DER ABBILDUNGEN ....................................................................... 10 VERZEICHNIS DER ANHÄNGE .............................................................................. 11 VERZEICHNIS DER SYMBOLE UND ABKÜRZUNGEN ............................................. 12 1 EINLEITUNG UND MOTIVATION ....................................................................... 14 2 ZIELSETZUNG UND KONZEPT ............................................................................ 16 3 THEORETISCHE EINFÜHRUNG .......................................................................... 18 3.1 Stickstoff in der Umwelt ........................................................................................ 18 3.2 Ammonium und Nitrat im Stickstoffkreislauf ........................................................... 18 3.3 Einflussfaktoren auf die Prozesse des Stickstoffkreislaufs ....................................... 21 3.4 Isotopenanalytik in den Umweltwissenschaften ...................................................... 22 3.4.1 Definition stabiler Isotope ................................................................................................... 22 3.4.2 Isotopieeffekte und Fraktionierung .................................................................................... 24 3.4.3 Delta-Notation ....................................................................................................................... 25 3.4.4 Fraktionierungs- und Anreicherungsfaktor ....................................................................... 28 3.5 Analyse stabiler Isotope mittels Isotopenverhältnis-Massenspektrometrie ................. 29 3.5.1 Allgemeine Informationen ................................................................................................... 29 3.5.2 Massenspektrometer ............................................................................................................ 29 3.5.3 Analyse stabiler Isotope mittels Elementaranalysator-Isotopenverhältnis-Massenspektrometrie-Kopplung (EA-IRMS) ...................................................................... 31 3.5.4 Analyse stabiler Isotope mittels GasBench II – IRMS ..................................................... 33 3.6 Ammonium und Nitrat im Kontext stabiler Isotope .................................................. 34 4 PROBENAUFBEREITUNGSMETHODEN ............................................................... 37 4.1 Bedeutung der Probenaufbereitung ....................................................................... 37 4.2 Probenaufbereitung für die δ15N-Isotopenanalyse von gelöstem NH4+ ....................... 37 4.2.1 Destillationsmethode ............................................................................................................ 37 4.2.2 Quecksilberfällung ................................................................................................................ 37 4.2.3 Diffusionsmethode ................................................................................................................ 38 4.2.4 Kationenaustausch................................................................................................................ 39 4.2.5 Fällung von Ammonium mittels Tetraphenylborat ........................................................... 39 4.2.6 Weitere Methoden ................................................................................................................ 40 4.3 Zusammenfassung der Probenaufbereitungsmethoden für die δ15N-Isotopenanalyse von gelöstem NH4+ ............................................................................................... 40 4.4 Probenaufbereitung für die δ15N- und δ18O-Isotopenanalyse von gelöstem NO3− ........ 41 4.4.1 Reduktionsmethoden ........................................................................................................... 41 4.4.2 Denitrifizierermethode ......................................................................................................... 41 4.4.3 Silbernitratfällung.................................................................................................................. 42 4.4.4 Bariumnitratfällung ............................................................................................................... 43 4.5 Zusammenfassung der Probenaufbereitungsmethoden für die δ15N- und δ18O-Isotopenanalyse von gelöstem NO3- ....................................................................... 43 5 ÜBERBLICK DER DURCHGEFÜHRTEN STUDIEN ................................................ 44 5.1 δ15N-Analyse von Ammonium in gefriergetrockneten, natürlichen Grundwasserproben durch Fällung mit Natriumtetraphenylborat ............................................................ 44 5.2 Weiterführende Optimierung der Denitrifizierermethode für die schnelle 15N und 18O-Analyse von Nitrat in natürlichen Wasserproben ..................................................... 44 5.3 Beispielhafte Identifizierung von Nitrifikation und Sorptionsprozessen von Ammonium als Feldstudie ...................................................................................................... 45 6 DISKUSSION UND AUSBLICK ............................................................................ 47 7 DANKSAGUNG ................................................................................................... 50 8 LITERATURVERZEICHNIS ................................................................................. 51 ANHANG ............................................................................................................... 61 / This thesis provides a method to identify the transformation of the nitrogen species ammonium and nitrate in polluted aquifers by analyzing the isotope ratios N-15 and O-18. Various preparation methods already exist, but are either labor intensive or time consuming and are therefore related with considerable costs. To achieve a broader applicability in environmental sciences, two simplified methods for the N-15 and O-18 stable isotope analysis of ammonium and nitrate in water were developed in this thesis. On the one hand, a precipitation method using sodium tetraphenylborate for the sample preparation of the N-15 isotope analysis for ammonium was modified, tested and validated. So far no studies could verify the applicability of this method for analysis of water samples containing ammonium. Therefore, the method was optimized for applicability to water samples, especially natural groundwater samples within this thesis. On the other hand, a common processing method for dissolved nitrate was optimized. The preparation and working time of the denitrification method was shortened without negatively affecting the accuracy of the measurement. For this purpose, two existing variants of the method were combined and modified. Furthermore, an exemplary field study was carried out to test the suitability of the preparation methods for process identification. A study area southeast of Berlin (Germany) containing an aquifer massively contaminated with ammonium served as a model location. Inside the area, the so-called BIOXWAND process, an in-situ process whereby oxygen is injected directly into the aquifer to promote nitrification, was developed and applied to the aquifer in terms of remediation. For isotope-based process identification, groundwater samples were taken twice a year from 2016 to 2019 from the BIOXWAND inflow and outflow and analyzed using the preparation methods developed. An analytical model was created for process identification.:VERZEICHNIS DER TABELLEN ................................................................................ 9 VERZEICHNIS DER ABBILDUNGEN ....................................................................... 10 VERZEICHNIS DER ANHÄNGE .............................................................................. 11 VERZEICHNIS DER SYMBOLE UND ABKÜRZUNGEN ............................................. 12 1 EINLEITUNG UND MOTIVATION ....................................................................... 14 2 ZIELSETZUNG UND KONZEPT ............................................................................ 16 3 THEORETISCHE EINFÜHRUNG .......................................................................... 18 3.1 Stickstoff in der Umwelt ........................................................................................ 18 3.2 Ammonium und Nitrat im Stickstoffkreislauf ........................................................... 18 3.3 Einflussfaktoren auf die Prozesse des Stickstoffkreislaufs ....................................... 21 3.4 Isotopenanalytik in den Umweltwissenschaften ...................................................... 22 3.4.1 Definition stabiler Isotope ................................................................................................... 22 3.4.2 Isotopieeffekte und Fraktionierung .................................................................................... 24 3.4.3 Delta-Notation ....................................................................................................................... 25 3.4.4 Fraktionierungs- und Anreicherungsfaktor ....................................................................... 28 3.5 Analyse stabiler Isotope mittels Isotopenverhältnis-Massenspektrometrie ................. 29 3.5.1 Allgemeine Informationen ................................................................................................... 29 3.5.2 Massenspektrometer ............................................................................................................ 29 3.5.3 Analyse stabiler Isotope mittels Elementaranalysator-Isotopenverhältnis-Massenspektrometrie-Kopplung (EA-IRMS) ...................................................................... 31 3.5.4 Analyse stabiler Isotope mittels GasBench II – IRMS ..................................................... 33 3.6 Ammonium und Nitrat im Kontext stabiler Isotope .................................................. 34 4 PROBENAUFBEREITUNGSMETHODEN ............................................................... 37 4.1 Bedeutung der Probenaufbereitung ....................................................................... 37 4.2 Probenaufbereitung für die δ15N-Isotopenanalyse von gelöstem NH4+ ....................... 37 4.2.1 Destillationsmethode ............................................................................................................ 37 4.2.2 Quecksilberfällung ................................................................................................................ 37 4.2.3 Diffusionsmethode ................................................................................................................ 38 4.2.4 Kationenaustausch................................................................................................................ 39 4.2.5 Fällung von Ammonium mittels Tetraphenylborat ........................................................... 39 4.2.6 Weitere Methoden ................................................................................................................ 40 4.3 Zusammenfassung der Probenaufbereitungsmethoden für die δ15N-Isotopenanalyse von gelöstem NH4+ ............................................................................................... 40 4.4 Probenaufbereitung für die δ15N- und δ18O-Isotopenanalyse von gelöstem NO3− ........ 41 4.4.1 Reduktionsmethoden ........................................................................................................... 41 4.4.2 Denitrifizierermethode ......................................................................................................... 41 4.4.3 Silbernitratfällung.................................................................................................................. 42 4.4.4 Bariumnitratfällung ............................................................................................................... 43 4.5 Zusammenfassung der Probenaufbereitungsmethoden für die δ15N- und δ18O-Isotopenanalyse von gelöstem NO3- ....................................................................... 43 5 ÜBERBLICK DER DURCHGEFÜHRTEN STUDIEN ................................................ 44 5.1 δ15N-Analyse von Ammonium in gefriergetrockneten, natürlichen Grundwasserproben durch Fällung mit Natriumtetraphenylborat ............................................................ 44 5.2 Weiterführende Optimierung der Denitrifizierermethode für die schnelle 15N und 18O-Analyse von Nitrat in natürlichen Wasserproben ..................................................... 44 5.3 Beispielhafte Identifizierung von Nitrifikation und Sorptionsprozessen von Ammonium als Feldstudie ...................................................................................................... 45 6 DISKUSSION UND AUSBLICK ............................................................................ 47 7 DANKSAGUNG ................................................................................................... 50 8 LITERATURVERZEICHNIS ................................................................................. 51 ANHANG ............................................................................................................... 61

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1 Abstract This thesis presents an analysis of fossil plants from the Cenomanian Peruc-Korycany Formation of the Bohemian Cretaceous Basin and from the Bückeberg Formation of the Lower Saxony Basin in Germany. Based on earlier studies, both areas provide sediments that are considered to have developed in tidally influenced fluvial systems. Studied fossil plants are represented by ginkgoalean plant leaves (Ertemophyllum, Tritaenia), branches of conifers (Frenelopsis) and lauroid angiosperms (Eucalyptolaurus). Frenelopsis, Eretmophyllum and Tritaenia are considered to be halophytic plants, while Lauroid angiosperms were considered to grow in fresh water conditions. The fossil plants were studied using cuticle analysis and two methods of stable carbon isotope analysis: Bulk carbon isotope analysis and Compound Specific Isotope analysis. For cuticle analysis samples were observed and documented macroscopically and microscopically. To specify the environmental conditions, recent samples from three salt marshes in Great Britain were studied and analysed using the same methods as the fossil samples. The data from all observations and measurements were processed and their interpretation supported the modelled environment based on the sedimentological data. Frenelopsis were growing in a haline environment with low...