Dr Toby Bolton, School of Biological Sciences, Flinders University

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Dr Toby Bolton

Current Research Opportunities (Honours / PhD)

Population structure of marine polychaetes with contrasting reproductive strategies

This project will examine the relationship between reproductive strategies of marine invertebrates (i.e. direct development, brooding offspring, lecithotrophic larval development, planktotrophic larval development) and their population genetic structure around Southern Australia. A range of polychaetes and molluscs with contrasting reproductive patterns will be used as experimental models. The project will also provide opportunities to characterize the reproductive patterns of marine invertebrates around Southern Australia, which are poorly known.

Population structure of Pateriella starfish on Eyre Peninsula.

This project will examine the population genetic structure of starfish of the genus Pateriella around the Eyre Peninsula, and will be co-supervised with Dr. Maria Byrne (University of Sydney). Species of Pateriella exhibit highly divergent reproductive strategies that make them outstanding models for investigations into evolution of reproductive patterns among marine invertebrates. The genus includes he world's smallest seastar, Patriella parvivipara, which is about the size of a match head and broods its offspring. The project would be based at Flinders University but will involve extensive field collections on the Eyre Peninsula.

Post-settlement ecology of the serpulid polychaete Galeolaria caespitosa

Galeolaria caespitosa is an extremely common polychaete that forms large calcareous aggregations in the intertidal zone around much of Southern Australia. Aggregations of G. caespitosa also provide refuge for a wide range of other organisms and are therefore likely to play important roles in the inter-tidal ecology of Southern Australia. This project will examine the settlement, development and ecology of aggregations of G. caespitosa, as well as the organisms associated with them. The accessibility of G. caespitosa creates a wide range of possibilities for manipulative field experiments.

Ecology of native oysters in Coffin Bay

Coffin Bay, Eyre Peninsula, South Australia, once supported a large fishery for the native mud oyster, Ostrea angasi. The fishery crashed due to overexploitation in the early 20th century and populations have never recovered. The history of the fishery and the people it supported are the subject of current archaeological studies, and there is growing community interest in restoring the native oyster populations. However, concerns have been raised about the extent to which native oysters would compete for planktonic food with introduced Pacific oyster, Crassostrea gigas, which is the basis of a large aquaculture industry. A study could be initiated examining the biology and ecology of O. agasi to determine the extent to which it may compete with the Pacific oyster. Additional studies could investigate whether changes in the Coffin Bay ecosystem resulting from agriculture and other human activities would allow a restoration program to proceed. There is also great potential for collaborative research with the School of Archaeology that would combine investigations into the history and ecology of the collapse of the O. agasi industry.

Investigating the effects of Tuna aquaculture on scavenging fish populations

The rapid expansion of the aquaculture industry in Southern Australia has created concerns about its potential ecological impacts and long term sustainability. Southern Australian marine ecosystems are unique, and studies on the effects of aquaculture conducted in other areas of the world are not directly applicable. Sustainable development of aquaculture in Southern Australia therefore requires greater knowledge of its ecosystem level effects in our unique environments. The consequences of organic enrichment resulting from Tuna aquaculture is one of the components of a current Cooperative Research Centre for the Sustainable Aquaculture of Finfish. An interesting finding of this research is that there is relatively little build up of organic material underneath the Tuna farms in South Australia compared to other areas of the world. A potential explanation is that organic material is rapidly processed by scavenging fish underneath the Tuna farms.

This project would involve investigations into the ecology of scavenging fish populations in response to Tuna farms. This project will be co-supervised with Dr. John Carragher (South Australian Research and Development Institute – SARDI) and will be supported by the Cooperative Research Centre for the Sustainable Aquaculture of Finfish. The project could be based in either Adelaide or Port Lincoln, but would require extended periods of field research in Port Lincoln.

The role of eggs accessory structures in facilitating deformation of invertebrate eggs in flow

Theory on flow predicts that a moving rigid object experiences drag proportional to the square of its speed. This reasoning does not apply if the object in flow is flexible because its shape becomes a function of velocity (i.e. it bends). Reconfigurations of bodies in fluid flow are common in nature and can result in a substantial reduction in drag that is beneficial to many organisms. For example, seagrass blades bend in flow, thereby reducing the amount of drag imposed on them, and hence the probability that they will be torn from the substratum. Recent studies on responses of simple structures to flow suggest that bending produces shapes that are self-similar in flexible bodies.

Previous research indicates that complex extracellular structures that surround the eggs of many marine invertebrates protect them from shear stress that they experience in the oviduct during spawning. Extracellular structures may protect eggs by facilitating deformation of eggs (a flexible body) in flow. Research could be readily initiated to investigate the responses of eggs to flow and the roles of extracellular layers in facilitating deformation. Collaborations could also be initiated with the School of Physical Sciences to use Atomic Force Microscopy to image the micro-structure of extracellular layers and to determine their elastic properties.

Assessment of the Ultrastructure and Physical Properties of Mollusc Egg Masses

Like the extracellular layers that surround the eggs of some free-spawning marine invertebrates, benthic egg masses of molluscs are reminiscent of engineered composites designed to withstand physical forces. These structures change physically and chemically as the larvae that they encapsulate develop and these changes are collectively referred to as ripening. The ripening process appears to protect offspring during encapsulated development and to facilitate hatching at the completion of development. In collaboration with Kirsten Benkendorff, a project could be undertaken to quantify the physio/chemical changes in the egg masses and capsules over the course of encapsulated development.

Please feel free to discuss any project ideas that you may have with me!

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