Quantifying the role of parrotfish in the production and cycling of carbonate in coral reef ecosystems

The study was funded by a NERC GW4+ DTP studentship Additional funding to support the cost of the Scanning Electron Microscope work was provided by the International Association of Sedimentologists through the post-graduate grant scheme. The DigitalGlobe Foudation provided the satellite imagery used to produce the habitat map in chapter 3 and its associated figures that appear throughout the thesisParrotfish are a diverse and ubiquitous group found on coral reefs worldwide. They are categorised into three main feeding modes; the browsers, scrapers and excavators, which together perform a number of important functional roles on coral reefs. Scraper and excavator parrotfish are common on most Indo-Pacific coral reefs where their roles in bioerosion, sediment production, grazing pressure and sediment reworking have been shown to influence benthic community composition, reef growth potential and sediment supply to reef habitats and reef associated sedimentary landforms. However, despite the widely known importance of parrotfish on coral reefs, our understanding of how their roles in carbonate cycling vary among species and among whole parrotfish communities in different reef habitats remains limited. This thesis produces original contributions to knowledge in the areas of species specific bioerosion estimates for the central Indian Ocean, bottom-up controls of habitat type on parrotfish assemblages and how variations in parrotfish assemblages translate to contributions to carbonate cycling processes among different reef habitats. The study was carried out across eight habitats on an atoll-edge reef platform in the central Maldives, where it was found that parrotfish community composition was driven by reef structural complexity and substrate type. Parrotfish occurred in six of the eight habitats, comprising ~44% of the platform area. Among these habitats, overall grazing pressure, bioerosion rates, sediment reworking and sediment production varied markedly. These processes were also found to have different spatial patterns over the reef platform, showing that they are not necessarily tightly coupled. In addition, reef habitats can vary in their importance for both sediment supply, and the relative importance of reworked sediment. Parrotfish produced a wide range of sediment size fractions, from 80%) between 125 and 1000 µm in diameter. This is comparable to the grain types found on local reef islands, and it is likely that the most significant supply of this material is from habitats on the atoll-edge side of the platform (which make up ~20% of the total platform area). Quantifying parrotfish functional roles and understanding the drivers behind these processes is important for informing future empirical and modelling studies, particularly as coral reefs undergo a time of dramatic environmental change.Natural Environment Research Counci

Reef habitat type and spatial extent as interacting controls on platform-scale carbonate budgets

This is the author accepted manuscript. The final version is available from Frontiers Media via the DOI in this record.A coral reefs carbonate budget strongly influences reef structural complexity and net reef growth potential, and thus is increasingly recognised as a key “health” metric. Despite this, understanding of habitat specific budget states, how these scale across reef platforms, and our ability to quantify both framework and sediment production values remains limited. Here we use in-situ census data from an atoll rim reef platform in the central Maldives to quantify rates of both reef framework and sediment production and loss within different platform habitats, and then combine these data with high-resolution habitat maps to quantify contributions to platform wide carbonate budgets. The net reef framework budget for the entire platform is extremely low (0.12 G, where G = Kg CaCO3 m-2 yr-1), with a very high proportion (143,745 kg or 65.1%) of total framework production generated within the platform margin reef zones, despite these comprising only ~8% of platform area. Net platform-scale sediment budgets are higher (1.04 G), but most is produced in the reef and platform margin hardground habitats, of which ~80% derives from parrotfish bioerosion. Significant quantities of new sediment (up to ~1 G derived from the calcareous green algae Halimeda) are produced only in one habitat. All lagoonal habitats have negative or neutral net carbonate budgets. These data demonstrate the marked inter-habitat differences in reef carbonate budgets that occur across reef platforms, and the major dampening effect on overall platform scale budgets when rates are factored for habitat type and size. Furthermore, the data highlights the disproportionately important role that relatively small areas of reef habitat can have on the maintenance of net positive platform scale budgets. Because of the intrinsic link between carbonate production rates and reef-associated landform development and maintenance, these findings also have implications for understanding reef-associated landform stability. In this context the reef island at this site has been highly mobile over the last ~40 years, and we hypothesise that such instability may be being exacerbated by the measured low overall rates of framework and sediment generation.Research was supported by a Leverhulme Trust Research Fellowship (RF-2015-152) to CTP, by 500 Natural Environment Research Council grant NE/K003143/1 to CTP, and by a Natural Environment 501 Research Council Studentship (NE/L002434/1) to RTY. We thank the DigitalGlobe Foundation for 502 providing and giving permission to use satellite imagery for Figures 1B and C, and Figure 6

Production of ammonia by Tritrichomonas foetus and Trichomonas vaginalis

Production of ammonia is difficult to find among the various studies of amino acid metabolism in protozoa. Several studies suggest that catabolism of arginine to ammonium is important for the growth of trichomonads. Trichomonads are amitochondriate zooflagellates that thrive under microaerophilic and anaerobic conditions. We were able to detect accumulation of ammonium ions and ammonia in cultures of Tritrichomonas foetus and Trichomonas vaginalis including those resistant to metronidazole. Ammonium ions and ammonia were detected using the indophenol colorimetric method. Aerobic overnight cultures had 0.9 mM of soluble ammonium (NH4+ and NH3) or a 20% greater concentration of ammonium relative to sterile tryptose, yeast extract maltose medium with heat inactivated horse serum that was incubated similarly. Production of ammonia itself was confirmed by analysis of a wick that was moistened with sulfuric acid (40 mM) and placed above the liquid in sealed cultures of a strain of T. vaginalis. The wicks from these cultures captured the equivalent of 0.048mM of volatile ammonia (NH3) from the liquid as compared to 0.021mM volatile ammonia from sterile medium after overnight incubation. Intact cells of trichomonads (0.1mg protein) incubated in Doran’s buffer and with or without (1 mM) L-arginine produced significant amounts of soluble ammonium (0.07 mM, 0.035 mM respectively) during 60 minutes. These amounts are similar to those reported for the metabolism of carbohydrates by trichomonads. The results indicate that ammonium ions and the more irritating ammonia are significant metabolites of trichomonads

The accommodation of diversity: liberal Quakerism and nontheism

This thesis is concerned with how Liberal Quakers accommodate a diversity of belief within their group. The project principally investigates the emergence of Quaker nontheism and the subsequent internal responses constructed as attempts to resolve the theist–nontheist divide. The thesis’s central contribution is in providing a thickened account of Liberal Quaker discursive landscape – i.e. one focused on the details of internal manifestations of emerging views and tensions. This is achieved via an engagement with sociological theories of ‘late modernity’ alongside previous work in Quaker Studies to build upon the understanding of Liberal Quaker dynamics. The thesis particularly highlights the prevalence of reflexivity within Quaker thought. Additionally, philosophical tools are developed primarily via an engagement with ‘postmodernist’ thinkers. The thesis argues that these ‘postmodernists’ respond to similar challenges to those faced by the Liberal Quakers. Consequently, the thesis demonstrates that developments in these ‘postmodernist’ projects provide comparative resources for illuminating emerging Quaker views. Accordingly, the thesis delineates Quaker responses as broadly following two streams: reflexive-structural and alteristic responses, and considers them with regard to developing expressions of Quaker identity/theology/ ‘orthodoxy’. The thesis has general implications concerning the changing shape of educated, liberal religious groups within a radically modern societal context

Arginine metabolism in Trichomonas vaginalis infected with Mycoplasma hominis

Both Mycoplasma hominis and Trichomonas vaginalis utilize arginine as an energy source via the arginine dihydrolase (ADH) pathway. It has been previously demonstrated that M. hominis forms a stable intracellular relationship with T. vaginalis; hence, in this study we examined the interaction of two localized ADH pathways by comparing T. vaginalis strain SS22 with the laboratory-generated T. vaginalis strain SS22-MOZ2 infected with M. hominis MOZ2. The presence of M. hominis resulted in an approximately 16-fold increase in intracellular ornithine and a threefold increase in putrescine, compared with control T. vaginalis cultures. No change in the activity of enzymes of the ADH pathway could be demonstrated in SS22-MOZ2 compared with the parent SS22, and the increased production of ornithine could be attributed to the presence of M. hominis. Using metabolic flow analysis it was determined that the elasticity of enzymes of the ADH pathway in SS22-MOZ2 was unchanged compared with the parent SS22; however, the elasticity of ornithine decarboxylase (ODC) in SS22 was small, and it was doubled in SS22-MOZ2 cells. The potential benefit of this relationship to both T. vaginalis and M. hominis is discussed

The career of Robert of Thurnham, 1191-1211

This thesis examines the career of Robert II of Thurnham a high ranking curial official, whose career in the royal service spanned the reigns of both Richard I [1189-1199] and John [1199-1216]. The thesis begins by examining Robert’s modest, if not humble, family background, before moving on to examine his career in the royal service. The thesis treats Robert’s curial career in broadly chronological order, starting with his activities on the Third Crusade [1191-2], and then examining his activities as seneschal of Anjou [1195-99], and later as seneschal of Poitou [1201-1204/5]. The thesis concludes by examining such factors as the rewards Robert received for his services to the crown, and the way in which these rewards affected his relationship with the wider Angevin society. This final chapter also attempts to provide more accurate dates, than have hitherto been offered, for the foundations of the religious houses that Robert established, by providing a detailed analysis of the surviving charter evidence, not all of which has been published. It also examines his controversial relationship with the Abbey of Meaux, and his relationship with his brother Stephen, and other prominent curiales. Two appendices are included. The first takes the form of an itinerary for Robert’s life, with the second examining the value to a study of Robert’s life of Peter of Langtoft’s ‘Chronicle’ and Thomas Burton’s ‘Meaux Chronicle’