The First Mass Extinction on Earth May Have Been Caused by Abrupt Changes in Marine Oxygen Levels

A recent study suggested that the first mass extinction on Earth may have been caused by abrupt changes in marine oxygen levels.

Quick changes in oxygen levels in the first mass extinction

According to the study, life on Earth was going through the Late Ordovician mass extinction, or LOME, which wiped out about 85% of marine species, 443 million years ago, as per ScienceDaily.

Long-term research into this mass extinction is ongoing, and scientists are looking into its potential causes, such as reduced loss of habitat in a rapidly cooling world or persistently low oxygen levels in the oceans.

Seth Young, a co-author and associate professor in the Department of Earth, Ocean, and Atmospheric Science, also said they didn't actually have any credible proof of an environmental or climate signature to link a certain early decline of these groups to a specific mechanism.

The graptolites and brachiopods, among other groups of organisms, began to decline very slightly earlier in this mass extinction interval, according to paleontologists.

The oxygen level dropped and was followed immediately by a rise.

This sudden change in oxygen occurred at the same time as the traditional first die-off of mass extinction and a significant expansion of the ice sheet over the former South Pole.

This ancient mass extinction is a crucial analog for the icehouse conditions and biodiversity loss that Earth is currently experiencing, as well as for attempting to predict Earth's future as our warming climate continues and the ice sheets recede.

This research used shales that have been deposited in deeper, oxygen-poor water, which record different geochemical signatures.

By using these shales, which record evidence from limestones from more oxygenated settings, the researchers were able to draw conclusions about global marine conditions instead of local conditions.

Too Much Oxygen Cause Oxygen Toxicity

About 21% of the oxygen in the air is oxygen. In medical treatments, higher concentrations are used, as per GoodRxHealth.

Higher concentrations, however, can harm your body even though they sometimes save lives. Oxygen toxicity is a medical condition that can be brought on by inhaling large amounts of oxygen.

Like any other substance, oxygen needs to be processed by our cells. Free radicals are a byproduct of this process, and low concentrations of them are not harmful. They can be eliminated by your body the same way as other waste materials.

But more free radicals are produced when you breathe in air with more oxygen. These free radicals can harm your lungs, heart, kidneys, thyroid, and brain if your body can't keep up.

Retinal damage can also happen if premature infants breathe oxygen at high concentrations. Permanent vision loss could be the result of this harm.

Additionally, throat and tracheal dryness and irritation can be brought on by higher oxygen concentrations during breathing.

As these body parts dry out, they start to crack, creating an opening for bacteria to enter the tissues and infect them and cause infection.

Related Article: Life on Earth Before Oxygen: 2.5-Billion-Year-Old Bacteria Discovered