Benthic diatoms are widely used as water quality indicators because they respond rapidly, sensitively and species-specifically to environmental change. However, deducing ecological tolerances from field observations relies on correlations, assumes that the most abundant taxa are growing optimally, and ignores covariance between environmental variables. Only experimental investigations can determine the effect of a particular factor on species growth.
Species delimitation in Nitzschia species is often problematic. Many species are small, and there is often considerable inherent morphological variation with size change. Other variation may be environmentally induced. Because many Nitzschia species are used as indicators of organic pollution in water quality assessments, it is important that they can be identified reliably. Therefore, the objectives of the project are: to clarify the taxonomy of N.
frustulum and N. palea using original material in the NHM; to determine the intrinsic and environmentally-induced morphological variation of N. frusutum and N. palea; to determine their ecological tolerances and optima, and to refine diatom indices that incorporate these species. Clones will be isolated and grown under a range of controlled conditions to determine intrinsic and environmentally induced variation, and to determine tolerances and optima for salinity, nutrients and organic pollution. Genetic variation between clones (intra- and inter-specific) will be assessed using allozyme electrophoresis. Based on the results, species diagnoses and ecological tolerances will be revised. Working at the NHM will provide advanced training in diatom culture techniques, diatom systematics and molecular techniques. My previous research on diatoms has been observational field ecology.
Experimental studies can test field hypotheses. I regard this complementarity as essential to developing a more rigorous approach to diatom ecology and to furthering my research career
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