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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.
131

Responses of Algal Epifauna to pulsed and chronic contamination of temperate Algal beds.

Roberts, David A, School of Biological, Earth & Environmental Sciences, UNSW January 2008 (has links)
Contaminants may affect marine organisms through various pathways with impacts evident across a variety of spatial and temporal scales. Organisms may encounter short pulsed exposures which contaminate surface waters for hours to days, or more persistent but patchy contamination of benthic habitats throughout their entire life-cycle. This thesis examines the responses of epifauna associated with macroalgae to a pulsed exposure of contaminants (storm-water input) and to chronic contamination via metal accumulation within temperate algal beds. The effects of storm water were monitored during a two-year survey of Sydney Harbour which sampled epifauna before and after heavy rainfall. Epifaunal assemblages declined throughout the harbour following storm events but for the most part these declines were not attributable to storm-water runoff. However, transient (&lt 4 d) and localized impacts of storm water upon physico-chemical characteristics of recipient water and some epifaunal groups were identified around storm drains. A novel field dosing technique tested the relative importance of freshwater and associated metals as causative agents of behavioural avoidance and direct mortality responses. Strong avoidance of storm-water plumes was found which could be entirely explained by freshwater inundation, with no additional effects of metals. No direct mortality was observed following brief exposures. Contaminants introduced by storm water may accumulate within the tissues of macroalgae and potentially pose persistent threats to epifauna. Colonisation of epifauna was reduced on algae with enhanced copper levels, and the nesting behaviour, feeding and survival of an abundant amphipod were all negatively affected by copper load. Subsequent field surveys identified sufficient copper, lead and zinc contamination in Sydney Harbour algal beds to pose direct toxic threats to epifauna. The abundance of herbivorous amphipods correlated negatively with the copper content of a common algal species. However, differences in metal accumulation between algal species resulted in spatially variable levels of contamination. Small-scale patchiness of contaminants within these landscapes may allow populations of mobile species to persist if contaminated hosts are avoided. In summary, epifaunal assemblages appeared resilient to storm-water pulses. Recovery of affected groups was rapid and large fluctuations in abundance appear to be part of the natural flux of epifaunal communities. In contrast, assemblages responded strongly to algal-bound contaminants and this has emerged as an important pathway of contaminant exposure and impact within algal habitats.
132

Management of the ecosystems of the Black Sea : alternative strategies for the control of water and nutrient inputs

McCarthy, Maurice M. 05 April 1995 (has links)
The objective of this thesis is to show that by separating the two major anthropogenic changes caused in riverine input to the north shore of the Black Sea, it is possible to describe distinct linkages between ongoing ecological changes in the Black Sea, and 1) flow reduction, and 2) nutrient load increase. An attempt is made to quantify the pertinent changes in the inputs of water, salt, and nutrients by modelling individual fluxes over time. The results of these computations are used to argue how the ecology of the Black Sea may be realistically partially restored to something like its former productivity. The origins of input changes to this system are evaluated in terms of their sources. The economic and social costs that will be involved in altering the quality and quantity of those inputs to allow recovery of the Black Sea are examined along with the benefits that may accrue through the restoration of water quality, fisheries and tourism. Mechanisms that may be relevant in the process of achieving the alteration of the inputs are discussed. / Graduation date: 1996
133

Σύσταση απορριμμάτων & εκτίμηση της συμβολής των πηγών απορριμμάτων σε 80 ελληνικές ακτές

Κορδέλλα, Σταυρούλα 18 March 2009 (has links)
Στην παρούσα εργασία έγινε εκτίμηση της σύσταση παράκτιων απορριμμάτων και της συμβολής χερσαίων και θαλάσσιων πηγών ρύπανσης σε 80 ακτές από όλη την Ελλάδα. Η συλλογή των δεδομένων έγινε με τη συμμετοχή εθελοντών, οι οποίοι κατέγραψαν ποσοτική (εκτίμηση ποσοστών των υλικών των απορριμμάτων) και ποιοτική πληροφορία (σχετικά με τις πηγές ρύπανσης) στην οποία έγινε παραμετροποίηση. Στον πίνακα δεδομένων που προέκυψε έγινε πολυδιάστατη στατιστική ανάλυση, όπου σύμφωνα με τα αποτελέσματά της, οι ακτές στην Ελλάδα διακρίνονται σαφώς με βάση τις πηγές ρύπανσης τους, ενώ επίσης χωρίζονται σε δύο στατιστικά σημαντικές ομάδες, σύμφωνα με τις πηγές και τα υλικά των απορριμμάτων που υπάρχουν σε αυτές. Το υλικό που βρέθηκε να κυριαρχεί στις ελληνικές ακτές είναι το πλαστικό (42,6% - 50,6%). / In the present study, the composition of beach litter and the contribution of land based and marine based litter - sources, were estimated for 80 beaches from all over Greece. The data was collected with the contribution of volunteers, who gathered quantitative (estimates on percentages of litter material) and qualitative information (on the beach litter sources). The results of multivariate statistical techniques, that were applied on the data matrix, which was formed after the parametrization of the qualitative data, showed that Greek beaches may be distinguished in to statistically important groups, according to the sources and material of beach - stranded litter. Plastic is the dominant material in greek beaches (42.6% - 50.6%).
134

A nutrient mass balance for nitrogen and phosphorous for the nearshore water of the west coast of Barbados, W.I., July 1996 to May 1997 /

Wellington, Christine. January 1999 (has links)
A mass balance approach was used in an attempt to quantify nutrient flux to the nearshore at the West Coast, Barbados, W.I. Total nitrogen and total phosphorus levels of the groundwater at inland pumping stations and above beach margins, as well as in the water of the nearshore zone and approximately 2 km offshore, were obtained. Nearshore groundwater seepage rates and salinity data were also taken. This study attempted to use this raw data to estimate flushing rates, nutrient loading rates, and nutrient loss rates, to ultimately create a picture of the fate of nutrients as they travel in groundwater into the nearshore zone. Annual loading for the entire West Coast was calculated at 1.46 x 105 kg NO3---N for nitrogen and 1.19 x 103 kg PO4 3---P for phosphorus. Mean nutrient levels in groundwater above the beach margin were estimated at 969.83 muM for nitrogen and 3.63 muM for phosphorus. For nitrogen and phosphorus respectively, these levels were twice and three times higher than at the pumping stations farther inland; and there was also a fourfold and fivefold drop in nitrogen and phosphorus, respectively, in the nearshore zone relative to this groundwater above the beach margin. This indicated that the dense coastal population at the West Coast was adding significant amounts of nutrient to groundwater after it had left the inland pumping stations. There were no patterns of gradation in nutrient concentrations detected within the immediate nearshore, making completion of an accurate mass balance impossible, though indicating that there was significant advection of submarine groundwater offshore, beyond the study zone. This may contribute to the poor health of West Coast reefs, where sewage and fertiliser leaching and runoff are suspected as the primary sources for nutrient input to submarine groundwater to the south and northern parts of the West Coast, respectively.
135

Responses of Algal Epifauna to pulsed and chronic contamination of temperate Algal beds.

Roberts, David A, School of Biological, Earth & Environmental Sciences, UNSW January 2008 (has links)
Contaminants may affect marine organisms through various pathways with impacts evident across a variety of spatial and temporal scales. Organisms may encounter short pulsed exposures which contaminate surface waters for hours to days, or more persistent but patchy contamination of benthic habitats throughout their entire life-cycle. This thesis examines the responses of epifauna associated with macroalgae to a pulsed exposure of contaminants (storm-water input) and to chronic contamination via metal accumulation within temperate algal beds. The effects of storm water were monitored during a two-year survey of Sydney Harbour which sampled epifauna before and after heavy rainfall. Epifaunal assemblages declined throughout the harbour following storm events but for the most part these declines were not attributable to storm-water runoff. However, transient (&lt 4 d) and localized impacts of storm water upon physico-chemical characteristics of recipient water and some epifaunal groups were identified around storm drains. A novel field dosing technique tested the relative importance of freshwater and associated metals as causative agents of behavioural avoidance and direct mortality responses. Strong avoidance of storm-water plumes was found which could be entirely explained by freshwater inundation, with no additional effects of metals. No direct mortality was observed following brief exposures. Contaminants introduced by storm water may accumulate within the tissues of macroalgae and potentially pose persistent threats to epifauna. Colonisation of epifauna was reduced on algae with enhanced copper levels, and the nesting behaviour, feeding and survival of an abundant amphipod were all negatively affected by copper load. Subsequent field surveys identified sufficient copper, lead and zinc contamination in Sydney Harbour algal beds to pose direct toxic threats to epifauna. The abundance of herbivorous amphipods correlated negatively with the copper content of a common algal species. However, differences in metal accumulation between algal species resulted in spatially variable levels of contamination. Small-scale patchiness of contaminants within these landscapes may allow populations of mobile species to persist if contaminated hosts are avoided. In summary, epifaunal assemblages appeared resilient to storm-water pulses. Recovery of affected groups was rapid and large fluctuations in abundance appear to be part of the natural flux of epifaunal communities. In contrast, assemblages responded strongly to algal-bound contaminants and this has emerged as an important pathway of contaminant exposure and impact within algal habitats.
136

Effects of wastewater effluent on macrobenthic infaunal communities at Christies Beach, South Australia /

Loo, Maylene G. K. January 2001 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, Dept. of Environmental Biology, 2001. / Includes bibliographical references (leaves 136-154).
137

Marine environment protection and biodiversity conservation the application and future development of the IMO's particularly sensitive sea area concept /

Roberts, Julian Peter. January 2006 (has links)
Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: p. 377-421.
138

An investigation of relationships between mass media coverage of ocean pollution and New Jersey ocean pollution legislation

Cantwell, Francine L. January 1991 (has links)
Thesis (M.S.)--Kutztown University of Pennsylvania, 1991. / Source: Masters Abstracts International, Volume: 45-06, page: 2705. Abstract precedes thesis as 2 preliminary leaves. Typescript. Includes bibliographical references (leaves 47-48).
139

Predicted achievement of strategic sewage disposal scheme in enhancement of marine water quality in Hong Kong /

Loke, Hing-wa. January 1997 (has links)
Thesis (M. Sc.)--University of Hong Kong, 1997. / Includes bibliographical references (leaf 84-86).
140

Modeling marine environmental impacts in Hong Kong with GIS /

Thorpe, John Paul. January 1996 (has links)
Thesis (M. Sc.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 87-94).

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