Dr Joanne Egan

Profile

Research Interests

I am a Quaternary Scientist primarily interested in environmental reconstruction through palaeolimnology. I have a general interest in palaeo-disturbance whether that is human disturbance and the associated impacts, or natural disturbance such as impacts of wildfires, tsunamis or rapid climate change.  My current research focusses on the terrestrial and aquatic impacts of distal tephra deposition from the climactic eruption of Mount Mazama.  There have been several studies looking at tephra impacts with varying results, and my research covers several themes which I intend to develop further: High resolution studies with multiple cores to detect disturbance and impact regimes, Holocene environmental change; the need for multiple proxies, and Tephrochronology and Bayesian modelling. 

High resolution studies with multiple cores to detect disturbance and impact regimes

As highlighted above, past studies have revealed a variety of impacts, but these have been low resolution studies based on one core.  I carried out high resolution (1 mm) pollen and diatom analyses on cores from lake fringes and deep water.  From these analyses, I found that high resolution sampling was essential as the duration of the impact lasted approximately 100-200 years, which can be easily missed.  This is important to consider for human impacts, and I would be interested in taking this approach in future research.  I also found from my PhD work that the fringe locations recorded a much stronger impact than the deep water cores, and the fringe location could reflected an isolated basin at that time. This is an important factor to consider when assessing disturbance regimes and pollution.  More work needs to be done to determine how important taking multiple cores is, and how doing so will help to understand land development and hydrological change.

Holocene environmental change; the need for multiple proxies

Pollen and diatom analyses were also carried out on the whole of the Holocene record.  The pollen assemblage indicated major shifts in climate such as the transition from the glacial to interglacial, the mid-Holocene maximum warmth and the early Holocene cooling.  However, the diatom assemblage recorded cyclical shifts, suggesting that these are more sensitive to abrupt climate change possibly relating to variations in solar activity and changes in air and water circulation patterns.  However, the diatom and pollen assemblages alone cannot help to determine the true cause of the shifts, and the diatom responses could be due to limnological changes or pollution, not responses to climate shifts.  Therefore, there is a need for more proxies in such studies such as isotope analyses and geochemical analyses, and I am very interested in gaining further knowledge and learning these applications.

Tephrochronology and Bayesian modelling

During my research it came to my attention that very little had been done in tephrochronology in the Pacific Northwest.  There was little geochemical data for the Mazama tephra, and other tephras found such as Glacier Peak and an earlier eruption of Mazama. There is a great potential for cryptotephra studies, and I would like to expand the use of Bayesian modelling in future work.

Teaching

Level 4:

• GEO1047 Practical skills in Geography and Environmental Science (module leader)
• GEO1049 An introduction to Natural Hazards (module leader)
• GEO1051 Geological hazards (module leader)
• GEO1045 Introducing Physical Geographies (contributor)
• GEO1046 Environmental issues (contributor)
• GEO1048 Introduction to Geographical and Environmental Science Research (contributor)
• GEO1140 Science of the Physical Environment (contributor)

Level 5:

• GEO2071 Research methods for Physical Geography and Environmental Science (contributor)
• GEO2073 Environmental Research in Practice (contributor)

Level 6:

• GEO3071 Natural Hazards (module leader)
• GEO3073 Environmental Change (contributor)
• GEO3140 Environmental Monitoring and Management (contributor)
• GEO3070 Dissertation (supervisor)

I have been involved in and lead many undergraduate and postgraduate modules covering a diverse range of topics including skills-based modules, research techniques, Natural Hazards, Environmental Change, Environmental Monitoring and Modelling and I have supervised dissertation students.  I have also been involved in many residential field courses to Cumbria, Mallorca, Iceland and Morocco.