A Study of the Microcoleous Lyngbyaceus Bloom in Moreton Bay, Queensland

Ollet, Christopher (2001). A Study of the Microcoleous Lyngbyaceus Bloom in Moreton Bay, Queensland Honours Thesis, School of Engineering, The University of Queensland.

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Author Ollet, Christopher
Thesis Title A Study of the Microcoleous Lyngbyaceus Bloom in Moreton Bay, Queensland
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2001
Thesis type Honours Thesis
Supervisor Peter Bell
Total pages 41
Language eng
Subjects 0904 Chemical Engineering
Formatted abstract
Every summer for the past few years an algal bloom has occurred in northern Deception Bay. This of environmental concern because the alga can affect human health and the health of wild life in the area. Through reviewing literature on the subject and by conducting experiments we have found out that the algae in question has been identified as Microcoleous lyngbyaceus. This algae contains endotoxins that can cause skin and eye irritation. Classification of the algae was difficult as there is no universal system for the identification of algae. Microcoleous lyngbyaceus is the name given by Francis Drouet to a number of algae previously thought to be of different species. Often these said
differences are due more to environmental factors rather than the specific cytology of the algae.

Microcoleous lyngbyaceus is a very versatile algae and it is found allover the world in both freshwater and saline environments. A specimen will adapt from salt water to freshwater as long as the change in salinity is gradual. It can also tolerate a remarkable temperature range but prefers water temperatures of between 25 and 30°C. It does require high light intensity to sustain healthy growth.

The area of the bay in which the algae is found is by no means the most disturbed part of the bay, however, it is rich enough in the nutrients thought necessary to sustain Microcoleous lyngbyaceus growth. These nutrients are nitrogen, phosphorus and iron. Microcoleous lyngbyaceus is fixes nitrogen from the atmosphere and so nitrogen concentrations are unlikely to affect it. The algae also has the ability (common to all cyanobacteria) to store phosphorus for future use. This means the relatively low total phosphorus concentration in the area is not necessarily a problem. In fact the experiments conducted suggest that too much phosphorus maybe toxic to Microcoleous lyngbyaceus.

The experiment was to find out how Microcoleous lyngbyaceus was affected by water quality. Specimens of Microcoleous lyngbyaceus were grown in water samples collected from four points around northern Moreton bay. It was found that these water samples would support the growth of Microcoleous lyngbyaceus. To some of the water samples extra Fe(III)EDTA and PO4 were added to see what effects on the growth rate of Microcoleous lyngbyaceus that these would have. When only phosphate was added to the water it was found the growth of Microcoleous lyngbyaceus was reduced. When iron was added to a water sample the growth significantly increased. Interestingly when phosphate was added to the iron enriched water samples the growth increased even more then with iron alone.

These results seem to indicate three things; one is that the extra phosphate added had a toxic effect on the Microcoleous lyngbyaceus. Secondly it appears that in the seawater samples iron is the growth limiting nutrient for Microcoleous lyngbyaceus and finally when there is sufficient iron in the water the added phosphate ceases to be toxic and actually enhances the growth of Microcoleous lyngbyaceus.
Keyword Microcoleous Lyngbyaceus Bloom

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
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Created: Thu, 08 Jan 2015, 13:18:45 EST by Asma Asrar Qureshi on behalf of Scholarly Communication and Digitisation Service