Anisotropy in the Natural Environment

Anisotropy is the property of being directionally dependent, as opposed to isotropy, which implies uniformity in all directions. Anisotropy occurs throughout the physical world and is perhaps most commonly encountered in material science but anisotropy also often occurs in nature in a number of ways. One example of this includes ?active fluid? systems. In such systems there are active organisms which are influenced by the flow of fluid around them but, crucially, also influence the flow. When the organisms are anisotropic (as is often the case) a model of such a system must include these factors, and models of bacteria and even larger organisms such as fish have started to be developed over the last few years in order to examine the order, self-organisation and pattern formation within these systems.

This proposal aims to use techniques from the theoretical modelling of liquid crystal systems to consider a number of different areas of the natural world and to consider the effect of anisotropy on the behaviour of important marine bacteria and larger organisations of fish. These models will provide important information on behaviour in altered environments, such as where man-made structures (i.e. sea-based wind, wave and tidal energy generation devices) and can inform developers and governmental policy in the future.

Anisotropy is the property of being directionally dependent, as opposed to isotropy, which implies uniformity in all directions. Anisotropy occurs throughout the physical world and is perhaps most commonly encountered in material science, where a material s physical properties may depend on specific directions. For instance, the absorbance, conductivity, strength, etc. are often different along different directions in a substance.

Anisotropy also often occurs in nature in a number of ways. For instance seismic anisotropy is the variation of wavespeed with direction due to the long range order of small scale features such as crystals, cracks and pores. The alignment of these features can create a directional dependence of the elastic properties of rock which is then observed through the anisotropy of seismic wave propagation and other extremely important properties (i.e. strength, crack propagation, porosity, electrical anisotropy, and electrical conductivity). This type of anisotropy can occur when the natural formation processes occur in an anisotropic way (i.e. through layering in sedimentary material or through extensional flows which solidify).

Geology is not the only area of the natural world where anisotropy occurs: other examples include ?active fluid? systems. In such systems there are active organisms which are influenced by the flow of fluid around them but, crucially, also influence the flow. When the organisms are anisotropic (as is often the case) a model of such a system must include these inherent asymmetries. Models of bacteria and even larger organisms such as fish have started to be developed over the last few years in order to examine the order, self-organisation and pattern formation within these systems.

This proposal aims to use techniques from the theoretical modelling of liquid crystal systems to consider a number of different areas of the natural world. In order to advance this work the principal investigator intends to spend one year collaborating with researchers in Strathclyde and at the Scottish Association for Marine Science (a world leading facility in this area) to fully immerse himself in this research area. With the knowledge gained from this collaboration research and application of modelling techniques during and subsequent to this project will be advanced significantly.