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Title: The benthic ecology of Carmarthen Bay
Author: Woolmer, A. P.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2003
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Carmarthen Bay, an extensive, shallow embayment off the south coast of Wales, UK, encompasses a wide range of rich and diverse coastal and marine habitats. Carmarthen Bay is an internationally important wintering ground for the Common Scoter duck, Melanitta nigra (Linnaeus). An extensive survey of the macrofauna revealed that Carmarthen Bay is dominated by the Tellina sub-group of Petersen’s Venus community characterized by the polychaetes Spiophanes Bombyx, Magelona spp. and Spio spp., the amphipods Perioculodes longimanus, Pontocrates arenaritus and Bathyporeia spp., and the bivalves Fabulina fabula, Mysella bidentata and Chamelea gallina. Spatial patterns of species abundance and richness are shown to be strongly influenced by hydrodynamic and sedimentary gradients. A wholly multivariate correlative technique to identify species or groups of species sensitive to environmental gradients were developed. Gradients of depth, proportion of mud in the sediment, median phi grain size, flood current velocity and wave height were all shown to elicit a macrofaunal community response in the Carmarthen Bay Tellina sub-community. The application of these techniques to environmental monitoring and ecological research are discussed. The population dynamics, size structure and growth parameters of F. fabula were determined and predictive models of abundance and distribution were developed. These provide evidence of an ontogenetic niche shift in F. fabula representing a novel optimal foraging strategy for sessile deposit feeding invertebrates. A study of the temporal variability in the Tellina sub-community redundancy revealed that is was subject to recruitment driven short-term variability in the abundance and dominance of commonly occurring r-selected taxa. Levels of structural redundancy and a successful process involving the numerically abundant taxa suggest that functionally equivalent taxa may be able to compensate for this variability. These results are discussed in the context of functional diversity and the role of biodiversity in ecosystem processes. An assessment of the Carmarthen Bay Tellina sub-community’s persistence and resilience to perturbation is made.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available