Final APEX this term: How Fire & Plant Feedbacks have Stabilised Atmospheric Oxygen on Earth
This week we are delighted to welcome a talk by Dr Rayanne Vitali, a postdoctoral researcher at the University of Exeter.
Final APEX this term: How Fire & Plant Feedbacks have Stabilised Atmospheric Oxygen on Earth
27 Mar 2026, 13:00 – 14:00
Our Astrobiology and Planetary Exploration (APEX) seminar series this Friday 27th March at 13:00 GMT features the following talk:
- Rayanne Vitali (Exeter) - Earth’s Oxygen Puzzle: How Fire & Plant Feedbacks have Stabilised Atmospheric Oxygen
An abstract for Rayanne’s talk can be found below.
This is the final APEX seminar this term, and takes place in Birkbeck room MAL 612, 6th floor of the Birkbeck main Malet Street building, and online. We warmly encourage in-person attendance to support our visiting speakers.
The APEX seminar series will resume in October 2026. Please keep an eye on these pages for updates nearer the time.
If you are not on our regular mailing lists and are interested in attending these seminars, please contact joanna.fabbri AT ucl.ac.uk.
Abstract
Over the past 400 million years, Earth’s atmospheric oxygen has remained within a remarkably narrow range, yet the mechanism behind its stability, often termed “the oxygen puzzle,” has been debated for decades. Fire has long been considered a key regulator through negative feedbacks involving vegetation and carbon burial. In this talk, I present work from my doctoral thesis that, for the first time, tests assumptions about the strength of fire–oxygen feedbacks, showing that this control weakens under high-moisture conditions. I propose a combined feedback mechanism, highlighting photorespiration as a key piece that, together with fire, stabilises oxygen. These findings reveal how interacting biosphere–atmosphere feedbacks can maintain stable planetary oxygen levels over geological timescales, providing insight into the processes that sustain habitability and informing how oxygen might behave as a biosignature on Earth-like exoplanets.
Links
APEX Seminars
The Astrobiology and Planetary Exploration (APEX) seminar series takes place this term on Friday lunchtimes, from 1-2pm, in Birkbeck room MAL 612, on the 6th floor of the Birkbeck main Malet Street building, and online. As in previous years, we will operate a hybrid (online and in-person) model for both speakers and attendees. Details of the forthcoming APEX programme can be found via the link below.
Some of our past APEX talks can also be viewed online.
Further information
Ticketing
Open
Cost
Free
Open to
Invitation Only
Availability
Yes
Organiser
Dr Andrew Rushby / Dr Keyron Hickman-Lewis / Dr Joanna Fabbri
Other events in this series
APEX is back! Organic–mineral associations in Jezero crater
We are delighted to welcome back our APEX seminar series with a talk from Dr Keyron Hickman-Lewis, Lecturer in Planetary Exploration at Birkbeck, University of London.
APEX this week: It Came From Deep Space! What we've learned about 3I/ATLAS in the first 100 days
For this week's APEX seminar, we are delighted to welcome a talk from Dr Mark Norris, a Senior Lecturer in the School of Engineering and Computing, University of Lancashire.
APEX this week: Hydrocarbon Hazes on Temperate sub-Neptune K2-18b
We look forward to the next talk in our APEX seminar series from Ruohan Liu, a PhD researcher studying exoplanets in the Astrophysics Group at UCL's Department of Physics and Astronomy.
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