Charcoal evidence that rising atmospheric oxygen terminated Early Jurassic ocean anoxia
"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 (pO2) leading to termination of an OAE after ∼1 Myr. Wildfire is highly responsive to changes in pO2 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. [...]"
Source: Nature Communications
Authors: Sarah J. Baker et al.
Jurassic drop in ocean oxygen lasted a million years
"Dramatic drops in oceanic oxygen, which cause mass extinctions of sea life, come to a natural end - but it takes about a million years.
The depletion of oxygen in the oceans is known as "anoxia", and scientists from the University of Exeter have been studying how periods of anoxia end.
They found that the drop in oxygen causes more organic carbon to be buried in sediment on the ocean floor, eventually leading to rising oxygen in the atmosphere which ultimately re-oxygenates the ocean."
Source: University of Exeter
Contact: Alex Morrison