36 resultados para Imperialism -- Book reviews


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The author reviews the stratigraphic diatom profile of Cumbrian lakes since the last glaciation. Knowledge of both present and previous interglacials suggests that a natural cycle of change is imposed on all lakes. The nature of inwashed material is dependant on climatic and natural soilcycles and this affects the water quality and sensitive aquatic biota. Anthropogenic effects are superimposed upon this with forest clearance and pollution. Whilst some Cumbrian diatom profiles extend over the entire post glacial, others cover only detailed sections relating to particular problems. Causes and effect of recent changes in lakes can be studied using indicator species but palaeocology contributes greatly to understanding of long term changes.

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This annotated bibliography covers literature to the end of November 1977, and includes references to samplers that could be used for the rapid removal of benthic invertebrates from natural substrata of rivers and streams. Marine samplers which have been, or could be, used in freshwater. Coverage of Russian literature is incomplete, although a selection of recent and important references are included. The references are arranged under the following headings, Reviews; Nets and quadrat samplers; Scoops, shovels and dredges; Grabs; Corers; Suction and air-lift samplers; Electroshocking samplers; Efficiencies and comparisons; and Samplers from catalogues. There is an index to samplers (by the common name) and an author index.

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This paper reviews the effectiveness of Gammarus scope for growth (SfG) as an indicator of water quality. In addition, the link between physiological changes and effects at higher levels of biological organisation is addressed. Exposure to a range of toxicants resulted in decreases in Gammarus SfG which were qualitatively and quantitatively correlated with subsequent reductions in growth and reproduction. Reductions in SfG were due principally to a decrease in energy intake (i.e. feeding rate) rather than an increase in energy expenditure. Gammarus pulex is an important shredder in many stream communities and stressed-induced reductions in its feeding activity were correlated with reductions in the processing of leaf litter by a semi-natural stream community. Hence, changes in the physiological energetics of Gammarus provide a general and sensitive indicator of stress which can be linked to effects at higher levels of biological organisation. Under long-term stress and hence prolonged reductions in SfG, animals may adapt by modifying their life-history strategies and producing fewer, larger offspring.

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The first of Alexander Agassiz’ voyages on the U.S. Fish Commission steamer Albatross in 1891 yielded significant scientific results. This paper reviews the background of the voyage, including the career path that led Agassiz to the back deck of the Albatross. We also give a brief account of the life and work of Samuel Garman. Garman wrote up the ichthyological material from this Albatross voyage in a magnificent book on deep-sea fishes published in 1899. This book was exceptional in its coverage, anatomical detail, and recognition of phylogenetically important morphology.

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