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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Circulation in the estuary of the Gros Mecatina River

Bobbitt, Judith. January 1978 (has links)
No description available.
72

Sediment dynamics of the Amatikulu Estuary, Central KwaZulu-Natal Coast, South Africa.

Le Vieux, Alain. January 2010 (has links)
Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.
73

Aspects of the dynamics of mercury cycling in a small Hawaiian estuary

Luoma, Samuel N January 1974 (has links)
Typescript. / Bibliography: leaves [201]-210. / xv, 210 leaves ill
74

The effects of trace metals on juvenile cockles (Austrovenus stutchburyi)

McConway, Alex January 2008 (has links)
This thesis investigated the population structure and spatial distribution of the cockle Austrovenus stutchburyi in estuaries and bays around the Canterbury coastline. Surveys investigated population attributes (average density and density of small cockles (< 10mm)) of Austrovenus stutchburyi in relation to physical environmental characteristics such as trace metals (copper, cadmium and zinc), sediment particle size, nitrogen and phosphorus levels, pore water and percentage organic matter of the sediment. Surface cover of flora and number of fauna present was also correlated with the density of cockles and small cockles < 10mm. MDS and PCA ordination showed that the biota was similar at 14 sites but differed significantly at the Pleasant Point Yacht Club (PPY) site. There was a positive correlation between fine sand (125 μm) and the average density of cockles and small cockles < 10 mm. High population densities of Austrovenus stutchburyi were also positively correlated with phosphorus levels, and percentage cover of Sea Grass (Ulva sp). However, Austrovenus stutchburyi density was negatively correlated with cadmium and zinc concentration, and percentage of mud present. The density of small cockles < 10 mm was negatively correlated with copper and cadmium concentration in the sediment and positively correlated with Topshell (Diloma subrostrata) numbers, Sea grass (Zostera muelleri) percentage cover, Sea lettuce (Ulva sp), percentage cover, and sediment particles sizes of < 63 μm (mud), 63 μm (very fine sand), and 125 μm (fine sand). Survival and behavioural changes of juvenile Austrovenus stutchburyi were investigated in relation to increased levels of copper, cadmium, and zinc in aqueous solution and sediment in the laboratory, and artificially increased levels in the field. In laboratory experiments in contaminated seawater it was found that, over time, copper and zinc had a detrimental effect on the percentage of juvenile cockles with their siphons extended as did copper concentration. Cockles 10 - 12 mm shell length exposed to different concentrations of copper had the lowest survival rate (25%) whilst cockles that were 5 - 7 mm in length had the greatest survival rate (69%). Cadmium did not affect survival or siphon extension in aqueous experiments. In the contaminated sediment experiments in the laboratory, the concentration of zinc (0, 20, 40, 80, 160 mg Zn/kg (dry weight)) and cadmium (0, 1.8, 5.6, 18, 36 mg Cd/kg (dry weight)) both decreased survival and burial of juvenile cockles in higher concentrations. Copper concentration (0, 5, 10, 25, 50 mg Cu /kg (dry weight)) decreased burial rates of juvenile cockles but did not affect survival. Transfer of juvenile Austrovenus stutchburyi within three sites in the Avon Heathcote Estuary during May 2007, found that site and exposure to copper, cadmium and zinc decreased the survival of the juvenile cockles. However, transfer of cockles between estuaries (Takamatua, Saltwater Creek and Avon – Heathcote Estuary) in May 2007 found that exposure to copper, cadmium and zinc had the main effect on survival of juvenile cockles. In July 2007 transfers of cockles between estuaries, site and exposure to copper, cadmium and zinc had an effect of survival on juvenile cockles. Cockle populations in the present research have shown a strong correlation with environmental variables, which can be used for management and conservation. The research in this thesis is a start to understanding the effects and implications of contaminants on survival, behaviour and recruitment of juvenile cockles. This research will benefit management strategies for increasing population numbers of Austrovenus stutchburyi.
75

Studies on nitrogen cycling processes in Lake Illawarra, New South Wales, Australia

Qu, Wenchuan. January 2004 (has links)
Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: leaf 178-199.
76

Eulerian-Lagrangian analysis of transport and residence times in estuaries and coasts /

Oliveira, Anabela Pacheco de, January 1997 (has links)
Thesis (Ph. D.)--Oregon Graduate Institute of Science and Technology, 1997.
77

The ichthyofauna associated with Taylor's salt marsh, Kariega estuary (Eastern Cape), South Africa /

Booth, Tara Loren. January 2007 (has links)
Thesis (M.Sc. (Zoology & Entomology)) - Rhodes University, 2009.
78

Aspects of the ecology and biology of the isopod, Exosphaeroma hylocoetes, (Barnard, 1940) in three temporarily open/closed southern African estuaries /

Henninger, Tony Oskar. January 2008 (has links)
Thesis (Ph.D. (Zoology & Entomology)) - Rhodes University, 2009.
79

Mixing dynamics in the Delaware Bay and adjacent shelf

Rice, Ana E. January 2009 (has links)
Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisor: A.D. Kirwan, College of Earth, Ocean, & Environment. Includes bibliographical references.
80

Shifts in environmental policy making discourses : the management of the St. Lucia estuary mouth /

Copley, Gail J. January 2009 (has links)
Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2009.

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