The Royal Society of Tasmania
Post Graduate Night
at the Royal Society Rooms
Customs House, Dunn Place, Hobart
on Tuesday, 5 November 2019
Our speakers for the evening are: Luisa Fitzpatrick, Habacuc Pérez-Tribouillier and Patrick Yates.
Their subjects range from lizards’ tails and black holes, to uses of radioactivity in studying the oceans.
Tail Loss and Telomeres in Lizards
Luisa studied an undergraduate degree in Marine Biology and Zoology at the University of Western Australia, where she then undertook her honours degree looking at sperm competition inbreeding in guppies with Professor Jon Evans and Dr Clelia Gasparini. She worked for an environmental consulting company for a few years and at the Western Australian Museum, then moved to Tasmania to begin a PhD in the evolutionary ecology of lizards with Associate Professor Erik Wapstra and Dr Geoff While. Her thesis work focusses on senescence in ectotherms and the links between telomeres, temperature, reproduction and life history using the Tasmanian lizard Niveoscincus ocellatus as a model system. During her PhD, Luisa spent 6 months working with Professor Mats Olsson and Dr Angela Pauliny at the University of Gothenburg in Sweden, attended several international conferences, was involved in organising and hosting several national conferences in Tasmania and helped with field work on wall lizards in Italy.
Abstract: One aspect of lizard ageing Luisa is particularly interested in is their ability to regenerate large portions of their body. Telomeres are protective caps on DNA that shorten with cell division and oxidative stress. Tissue regeneration such as regrowth of a body part may influence an organism’s telomere length as growth can increase both cell division and oxidative stress. Examining the effect of tail regrowth on telomeres in a lizard, Luisa and colleagues found that telomeres lengthened in lizards with intact tails while oxidative stress decreased in those re-growing tails. This suggests that tail regeneration involves a response to oxidative stress which comes at a cost to telomere repair. This change in telomere maintenance demonstrates a potential long-term cost of tail regeneration.
It’s not only bad news: how radioactivity is used to study the ocean
Habacuc has been interested in the ocean since an early age, spending long days in the tropical beaches of southern Mexico and then studying a bachelor degree in oceanography and a M.Sc. in marine geochemistry. During his masters, Habacuc worked alternatively as a guide taking tourist to snorkel with the whale shark in La Paz, Mexico. In 2015 he moved to Hobart to start a PhD in the Institute for Marine and Antarctic Studies with Dr Zanna Chase, Taryn Noble, Ashley Townsend and Andrew Bowie. As part of his PhD, he got involved in the analytical side of oceanography, developing a technique to measure radioactive elements in seawater at extremely low concentrations. Recently he submitted his thesis and now he is working as a research assistant for Dr Taryn Noble at IMAS. When he is not in the lab, or in front of the computer, you might very likely find him SCUBA diving or spearfishing somewhere on the Tasmanian coast.
Abstract: Since radioactivity was discovered towards the end of the 19th Century, it had a big impact on society. Many of us think of radioactivity as something negative (fair enough). However, it represents an incredibly useful tool to study how our Planet works! In this talk, I would like to introduce you to the basic concepts of radioactivity and how they are applied to study the ocean. Then I will tell you how I applied it to study the Southern Ocean. The Southern Ocean is the largest high nutrient, low chlorophyll region in the global ocean. In these regions, phytoplankton growth is minimum despite the abundance of nutrients (let’s remember that phytoplankton is like the plants of the ocean). The cause of this is because most of the Southern Ocean is iron deficient. When iron reaches these “anaemic” regions, big “blooms” of phytoplankton extending for thousands of square kilometres appear. These blooms have the potential of absorbing atmospheric CO2and if the conditions are right, to transport in into the deep ocean, thus having a potential impact on climate regulation. In my thesis, I used thorium and neodymium isotopes to investigate how iron reaches and fertilizes the remote region of the Kerguelen Plateau. This region hosts the largest bloom in the Southern Ocean and also Australia’s only active volcano.
Black holes & galaxy evolution in under 20 minutes
Patrick completed his Bachelor of Science at the University of Tasmania (UTAS), majoring in Physics and Applied Maths, before continuing his studies with an honours degree supervised by Dr. Stanislav Shabala and Dr. habil. Martin Krause. His honours topic was studying how black holes in the centre of massive galaxies modulate their impact on their host environment. Patrick was unable to escape the pull of black holes, and returned to UTAS to study a PhD, again supervised by Dr. Stanislav Shabala and Dr. habil. Martin Krause. His main area of research is modelling the effect black holes have on their host galaxy as a function of different environments. As part of his PhD studies, Patrick spent 3 months working with Prof. Martin Hardcastle and Dr. habil. Martin Krause at the University of Hertfordshire in England, attended the XXXth International Astronomy Union General Assembly in Vienna, and attended several national and international conferences and workshops.
Abstract: At the center of nearly every massive galaxy cluster lies a supermassive black hole, so dense that not even light can escape it’s gravitational pull. Surrounding this supermassive black hole is an accretion disk, formed as matter spirals inwards onto the black hole. The supermassive black hole, accretion disk, and region immediately surrounding the two are called the Active Galactic Nucleus (AGN) of a galaxy, and are thought to play a key role in how galaxies evolved into what we can observe today.
In this talk I will focus on radio jets, which are superheated and relativistic jets of plasma launched from the accretion disk that punch through the environment and can produce structures 10 times larger than the diameter of our own galaxy, the Milky Way. In particular I will look at how these radio jets are formed, how they grow to such large sizes, and how their violent passage through the environment is responsible for maintaining the delicate balancing act that prevents the catastrophic collapse of galaxy clusters. In my research I have developed state-of-the-art numerical simulations of these jets launched into realistic galaxy cluster environments, offering the perfect laboratory setting in which to quantify and model their effects on the host environment, and apply these findings to observations. One of the key findings from my research is the need to understand and accurately model the galaxy cluster environment in order to interpret the increasing number of radio jet observations.