Charcoal evidence that rising atmospheric oxygen terminated Early Jurassic ocean anoxia.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28497785.
- Also identified by DOI 10.1038/ncomms15018 and PMC identifier 5437290.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The Toarcian Oceanic Anoxic Event (T-OAE) was characterized by a major disturbance to the global carbon(C)-cycle, and depleted oxygen in Earth's oceans resulting in marine mass extinction. Numerical models predict that increased organic carbon burial should drive a rise in atmospheric oxygen (pO<sub>2</sub>) leading to termination of an OAE after ∼1 Myr. Wildfire is highly responsive to changes in pO<sub>2</sub> implying that fire-activity should vary across OAEs. Here we test this hypothesis by tracing variations in the abundance of fossil charcoal across the T-OAE. We report a sustained ∼800 kyr enhancement of fire-activity beginning ∼1 Myr after the onset of the T-OAE and peaking during its termination. This major enhancement of fire occurred across the timescale of predicted pO<sub>2</sub> variations, and we argue this was primarily driven by increased pO<sub>2</sub>. Our study provides the first fossil-based evidence suggesting that fire-feedbacks to rising pO<sub>2</sub> may have aided in terminating the T-OAE.
Medical subject headings
- Atmosphere
- Carbon
- Charcoal
- Oxygen