Due to the current trends of global warming and how drastically the atmosphere is changing, scientists have feared what would be Earth's sixth mass extinction. International researchers worked on a new study published in Nature Geoscience, adding carbon isotope records into a geochemical model to understand history's largest mass extinction. The study is part of the European Union's Innovative Training Networks project known as BASE-LiNE Earth.
Over 250 million years ago, the most severe environmental crisis known as the Permian/Triassic boundary drastically changed the evolution of life. Gathering climate change over time has allowed the team to develop a new boron-isotope-derived seawater pH record from fossil deposits to understand how the greatest mass extinction occurred.
Ancient Ocean Acidification
The team discovered the vital role of ocean acidification that lead to the mass extinction millions of years ago, and the common patterns in today's climate change. Results also showed the consequences that the greenhouse gas effect has on the marine environment, warmed the oceans' surface temperature, and widespread sulfide poisoning and deoxygenation of the oceans during the Triassic period.
Professor Uwe Brand from Brock University said that the past teaches us how the mass extinction "occurred in pulses, with each pulse constricting the hospitable environment further and further, cascading down to the extinction event over a short geological timeline." At the time, carbon dioxide emissions came from volcanism events that resulted in climate change.
Geochemical signals were discovered in the shells of brachiopod fossils. Brachiopods were a group of sea creatures that live in hard valve shells or lampshells. They were commonly found near the shore and were largely affected by increasing surface temperature.
The Italian researchers, who are experts in fossil sites and geography, located fossils with evidence of events before and during the mass extinction. Meanwhile, the team from Germany analyzed the isotopes from the fossils and modeled the processes. The geochemical study model also displayed how large deposits of carbon dioxide damaged parts of the environment where life could survive, shared the authors.
Ongoing Mass Extinction
The dramatic decline of ocean pH is also observed in today's climate change trends. Areas such as the Great Barrier Reef has experienced mass coral bleaching due to warming temperatures. In another study earlier this year explained how the sixth mass extinction is not just a problem of the future; it is ongoing and irreversible.
Carbon gas emissions no longer come only from rampant volcanic activity, but from deforestation, burning fossil fuels, vehicles, agriculture, illegal wildlife trade, and many other human activities. Moreover, many of the species predicted to go extinct are already endangered and could cause a chain reaction of extinction.
Studying the evolution of climate change is vital since 90% of marine life vanished at the time and 70% of terrestrial species disappeared. Scientists fear that the next mass extinction, due to human activity, may repeat the Permian-Triassic mass extinction or even worse.
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