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A posterior gill of the common shore crab Carcinus maenas (Crustacea:Decapoda) was used to study the effects of sublethal copper concentrations on gill morphometry, and gill cell ultrastructure and distribution. Primarily, the ultrastructure and distribution of gill cells in the untreated gill of crabs acclimated to 35‰ seawater were characterised. Gill ultrastructure was subsequently shown to vary markedly at 10‰ compared to 35‰ seawater. Ultrastructural and distributional, rather than gross morphological, change occurred in the gill following exposure to copper at each salinity. Ultrastructural studies showed that as the length of copper exposure increased the gill epithelial layer became highly vacuolated, the number of plasma membrane infoldings and mitochondria became reduced, the microtubular network became disrupted, the endoplasmic reticulum became swollen and the cell cytoplasm contained many free ribosomes. Copper exposure also resulted in an increase in the number of haemocytes in the gill, some of which became attached to the basal epithelial cell surface or actually infiltrated into the epithelial cell cytoplasm. Ultrastructural change was more extensive when copper was administered at 35‰ rather than 10‰ seawater. These effects are described and correlated with previously documented biochemical and physiological responses to heavy metals in crustaceans. In addition, the elemental composition of the gill granular haemocytes suggested they play an important role in the immobilisation and removal of copper-from the gill. This study has shown the way forward in creating a better understanding of the mechanisms behind heavy metal toxicity in marine organisms is the use of environmentally realistic concentrations of heavy metal administered in flow-through seawater systems.

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The early 1990s saw the publication of important academic works on the subject of heavy metal music. These works were seminal in that they were the first to recognise and interrogate, in any substantial way, a topic that had been, until then, valued only as a cultural/sociological subject. Those ground-breaking works included Robert Walser's 1993 publication Running with The Devil: Power, Gender and Madness in Heavy Metal and Deena Weinstein's Heavy Metal: The Music and its Culture first published in 1991. Both works however, present heavy metal in broad terms, creating a wide paradigm that includes bands with widely differing musical syntax and aesthetic concerns (e.g. Cradle of Filth to Bon Jovi). These generalisations, being based on the perceived commonality of such concepts as power-chords and gendering, form something of a paradox that has been unquestioningly embraced by subsequent authors and so sustaining that opinion. I have challenged these generalisations and asserted that hard rock and heavy metal are distinctly different generic forms in both musical syntax and aesthetic. Moreover, I have argued that both Black Sabbath and Led Zeppelin were pivotal in the formation of heavy metal and hard rock respectively and that the first six albums of both bands were particularly significant to the generic evolution of both forms of music. Heavy metal has evolved and become an established form of music over the last three and a half decades but vitally retains the central coding established in Black Sabbath's early work, not least the consistent utilisation of key intervals such as the tritone and flat 2nd, modal riffs, down-tuned guitars, aggressive performance techniques, episodic structuring and anti-patriarchal themes. By contrast, Led Zeppelin made significant contributions to the evolution of hard rock through a re-working of blues-based themes and syntax and the development of an eclectic repertoire. This work deconstructs that evolutionary process, highlighting the distinct nature of both forms.

Minuartia verna (L.) Hiern and Thiaspi alpestre L. are recognized as relict elements of a preglacial montane flora in the British Isles and, as such, display a markedly disjunct distribution pattern. Their present-day distribution shows a close association with metalliferous mine workings, particularly in the Pennines, where both species have become prominent components of the flora of calcareous lead mine wastes. By comparison with M. verna, T. alpestre is more restricted in its distribution and is a rarer species. The work reported in this thesis attempted to provide an explanation for this pattern of distribution in the southern Pennines on the basis of comparative studies of the autecology and genecology of the species, their population biology and dynamics in the field and their responses to competition from other species. Both field and laboratory studies confirmed that the two species were highly tolerant of the heavy metals lead, zinc and cadmium. Short- and long-term solution culture experiments on tolerance and uptake of these heavy metals by a range of populations of both species are reported. Tolerance to other toxic metals was also investigated. T. alpestre showed superior tolerance to M. verna in these experiments, and emerged as a metal-accumulating species. M. verna by contrast, operated some degree of metal exclusion, but metal uptake and distribution differed for the various metals in both species and seasonally. Differences in metal tolerance and uptake characteristics alone could not explain the different local distribution patterns in the field, as sites of similar metal status are colonized by both the two species together and by M. verna alone. A study of inter-population variation in morphological characters showed considerable genetically-based variation in both species. M. verna was however more variable. Some of the variation detected was interpreted as being ecotypic in origin. The contrasting breeding of the two species and their seed biology are considered to be major factors in explaining the present-day distributions of the two species. The tendency for inbreeding in T. alpestre has severely limited its genetic variability within populations and potential for spread. Seedling mortality of both species in their natural habitats is very high, and survival can be related to early shelter effects of neighbouring plants. Both species, however, emerge as weak competitors as predicted from their preference for open habitats with much more bare ground. The relevance of these studies to the interpretation of the present-day global distribution of the two species and their evolutionary biology is discussed.

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