Thesis (M.Sc.-Res.)--University of Wollongong, 2007. / Typescript. Includes bibliographical references: leaf 96-109.

Thesis (Ph. D.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (leaves 128-138). Also available via the World Wide Web.

Graduation date: 1987

Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005. / Includes bibliographical references.

Thesis (M.A.)--Humboldt State University, 2005. / Includes bibliographical references (leaves 55-58). Also available via the Internet from Humboldt Digital Scholar.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 153-167). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 153-167). Also available on the World Wide Web.

The distribution of a range of artificial radionuclides, derived from the authorised discharges of the Sellafield nuclear fuel reprocessing plant, have been determined in a core sampled from the intertidal sediments in the Esk Estuary. The plutonium-alpha activity profiles qualitatively resemble the Sellafield discharge histories for these isotopes, suggesting that the plutonium is largely immobile in the sediments. The beta-emitting 241Pu isotope activity profile was also determined for the sediments using the beta/alpha discriminator on a low-level liquid scintillation counter and qualitatively resembles the Sellafield discharge history. The 241Am activity profile represents the sum of americium both from Sellafield discharges and from the decay of its parent isotope 241Pu. The 244Cm activity profile was examined to see if its relationship to 241Am could be used as a marker of the Sellafield "discharge only" 241Am but this proved to be unsuitable. The 241Pu measurements were therefore used to calculate the amount of 241Am ingrowth and a deconvolved 241Am profile was estimated. The presence of the short-lived isotope 242Cm in the core can only be due to the precursor isotope, 242mAM, supporting its production. The first direct environmental sample measurements of the anthropogenic isotope of uranium, 236U, have been made using accelerator mass spectrometry. Coupled with 238U/235U atom ratios, and the known operational history of Sellafield, these data provide evidence that uranium has limited movement within the core. 237Np activity profiles in cores from west Cumbrian area are limited and the concentrations determined here are very similar to findings of other authors who have sampled close to this sampling site. The profile does not resemble the known Sellafield discharges suggesting that some redistribution of neptunium in the core is occurring. Finally, a quantitative model has been developed to examine the relationship between the Sellafield discharge histories and the sediment profiles, in terms of transport to the sampling site via an offshore mud patch which acts as a buffer. A prediction of the Sellafield discharge history for 236U, which is unknown, has been made, and the model has also been used to evaluate the potential mobility of the actinides that have been studied. A long-term prediction of the transfer of radionuclides to the intertidal sediments has also been made.

Thesis (Ph.D.)--Oregon, Dept. of Biology Vita Bibliography: l. 118-122

Although sand deposits are present on many intertidal rocky shores, their effects on species richness, zonation and trophic structure have often been overlooked. This study is the first to recognise sand as an important abiotic factor on South African rocky shores. Rocky shores in the eastern Cape Province of South Africa are subject to extensive sand inundation and are composed of two hard substrata of differing topographies. Four sites on one substratum and six on the other were sampled quantitatively using quadrats. The biota were identified, counted and/ or weighed to provide a matrix of species biomass and numbers in separate zones. This matrix was then analysed using ordination and classification. A total of 321 species were identified which is more than local rocky or sandy shores. While the intermediate disturbance hypothesis would predict high species richness on these shores, it does not fully explain this richness nor the distribution of species assemblages. Habitat heterogeneity, including the dynamics of sand deposits, is strongly influenced by substratum topography and is the most important factor generating species richness. Abrasion by sand (sand scour) causes local reductions in richness but the presence of semi-permanent sand deposits allows habitation by psammophilic and sand-dependent species. As a result the biota of a sand inundated rocky shore includes both a full rocky shore and a large sandy beach component. Substratum topography controls patterns of sand deposition and retention and community analysis showed that samples were clustered primarily according to species richness and secondarily according to substratum type. Ordination of species identified an arc of species assemblages of decreasing levels of sand tolerance. These corresponded to sample groupings so that th assemblages found in various habitats were characterised by particular levels of sand tolerance. The presence of sand has a negative effect on the biomass of primary producers and filter feeders but a positive effect on the biomass of deposit feeders. Because sand is retained to different degrees in different zones, trophic structure varies between zones and to a lesser extent, between rock types. In general, however, the trophic structure of sand inundated rocky shores is similar to that of non-inundated shores.