Dr Vilma Pérez1
1University Of Adelaide, Adelaide, Australia
Biography:
Vilma is a microbial ecologist based at the Australian Centre for Ancient DNA at the University of Adelaide, Australia. She completed her PhD in Biological Sciences at the University of Antofagasta, Chile where she studied the adaptation strategies of microbial communities to extreme environmental conditions in the High Andean Altiplano in northern Chile. In 2019, she began a postdoctoral position at the University of Adelaide to specialise in the study and use of ancient environmental DNA. Currently, her research focuses on reconstructing microbial communities from present and past environments using environmental DNA techniques. Her goal is to use this information as bioindicators, providing insights into how environments have changed or responded to disturbances over time.
Abstract:
Environmental microbial communities play a crucial role in post-disturbance ecosystem recovery, supporting higher trophic life forms and essential ecosystem functions. However, our understanding of how environmental microbiomes respond to disturbances over extended temporal scales, relevant to ecosystem recovery (spanning decades to millennia), remains limited. This project aims to address this gap by using microbial ancient DNA (aDNA) preserved in lake sediments to reconstruct the long-term record of changes in microbial composition in response to environmental disturbances in South Australian environments throughout the Holocene.
The results revealed a high diversity of microorganisms across the three domains of life—Archaea, Bacteria, and Eukaryota—along with increasing levels of DNA damage throughout the sediment core, confirming the presence of authentic aDNA. The analysis indicated significant shifts in taxonomic composition identified through sedimentary DNA, with ecological changes driven by an increase in families containing halotolerant and halophilic taxa, commonly found in hypersaline environments around 700 and 2500 years ago, suggesting changes in saline conditions in the lake. Additionally, taxa belonging to the Actinobacteria and Firmicutes phyla were found to be differentially more abundant in sediments associated with high charcoal records. Previous studies have shown that these phyla tend to proliferate in soil microbiomes following drought and fire events, likely due to their high tolerance for environmental stress.
Overall, these findings significantly enhance our understanding of the ecological and evolutionary impacts of environmental changes, providing crucial insights that can inform conservation strategies in the face of ongoing and future climate change.