Master of Environmental Science (Research)
School of Earth and Environmental Sciences
Curtis, Gregory, An investigation of the possible influence of microorganisms on the uptake of trace metals by ulva lactuca, M.Env.Sc.Res thesis, School of Earth and Environmental Sciences, University of Wollongong, 2009. http://ro.uow.edu.au/theses/544
Trace metals are actual or potential pollutants in estuarine and coastal ecosystems. Anthropogenic activities, such as mining, industries and waste streams, can result in an increased release of trace metals into the environment at concentrations that may impact on the health, biological diversity and use of coastal ecosystems. They can be transported in food chains after absorption from the water by plants and consequently assessing the behaviour of metals requires an understanding of the factors that control the uptake of metals by organisms. In an attempt to investigate the effect of microorganisms on metal behaviour this study examines the effect that bacterial concentrations in solution have on the uptake of two sample trace elements, cadmium and selenium, by the algae Ulva lactuca. Algae collected from the Coledale area were tested for metal uptake in the presence of bacteria cultured from waters in the same area. Different concentrations of bacteria in solution were inoculated into salt-water media that contained samples of the algae and known concentrations of radioisotopes of selenium and cadmium. The algae were measured, by radiochemical methods, for metal uptake rates under the different treatment conditions. No overall conclusions could be developed as it proved difficult to maintain measurable differences between the bacterial inoculant concentrations in the experimental media. The differing concentrations of the bacterial treatments was the main variable in the experimental design and thus an analysis of the other experimental results, such as algae uptake, against these treatments was inhibited by the lack of significant difference within the bacterial measurements. The study did, however, provide valuable information for developing new experimental procedures to improve any further research into this area. A modified experimental procedure is proposed so that the impact of this important component (bacterial concentration variation) on metal behaviour in coastal waters can be investigated in more detail.