PERMIAN-TRIASSIC CAS

Investigating the effects of past global ocean acidification on marine ecosystems: A novel multiproxy approach

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 Obiettivo del progetto (Objective)

'The on-going acidification of modern oceans is a major issue of concern because it may have serious consequences for the survival of shelly marine invertebrates as the 21st century progresses. This is driven by anthropogenic CO2 release and the additional consequence of global warming is predicted to produce ocean de-oxygenation within a century. A better understanding of such effects will come from study of past ocean acidification and anoxic events but this objective is hampered both by poor constraint of ancient pH and redox values. This study aims to develop a new stable isotope technique – using Ca isotope fluctuations – to monitor ocean carbonate budgets and to evaluate the S isotope record of the oceans, a system primarily affected by ocean redox and evaporite burial. This approach will be applied to the end-Permian catastrophe, the greatest mass extinction of all time, to evaluate the hypothesis that the marine biotic crisis was caused by acidification and anoxia. Comparisons will be drawn with the non-steady state oceans of the late Precambrian Snowball Earth world when similar perturbations in ocean chemistry produced similar rock types to those seen in the aftermath of the Permian extinction. This uniquely, multi-pronged geochemical approach will allow coupled box modelling of the marine Ca and S budget and thus for the first time it will be possible to relate changes in these systems to oceanic oxygenation and pH levels and the contemporaneous mass extinction.The multi-pronged geochemical approach of this research will ultimately help to better constrain the timing and future effects of the anthropogenic emissions of CO2 on ocean acidification, marine biologic activity and global biogeochemical cycles.'

Introduzione (Teaser)

A recent research project has shown that high levels of carbon dioxide (CO2) in the atmosphere have historically been linked to major ocean extinction events.

Descrizione progetto (Article)

Rising global CO2 levels are driving acidification and deoxygenation of the world's oceans, with unknown consequences for marine life. Researchers can use isotopes (heavier or lighter versions of an element) to investigate whether high atmospheric CO2 was the cause of past marine extinction events.

The EU-funded PERMIAN-TRIASSIC CAS (Investigating the effects of past global ocean acidification on marine ecosystems: A novel multiproxy approach) project aimed to use changes in various isotopes in the geological record to understand major oceanic extinction events. Specifically, researchers looked at the mass extinction event at the end of the Permian period (300-250 million years ago).

Principally, the project was looking for the impact of a rapid increase in atmospheric CO2 at the end of the Permian, caused by volcanic activity. It achieved this by studying isotope fluctuations in carbonate and black shale deposits in Australia, Canada, China, Italy, Norway, Oman and Turkey.

Project members found that the Permian mass extinction was linked to a loss of oxygen in the world's oceans. The project also found that the most likely cause was global warming, which affected ocean chemistry for nearly a million years.

This research further showed short-term ocean acidification events around the same time as the mass extinction. Similar environmental changes were observed prior to another major climate change event, in the late Neoproterozoic period.

PERMIAN-TRIASSIC CAS has shown the overwhelming effects that increased global CO2 can have on ocean life through acidification and deoxygenation. These findings provide insight into the potentially devastating effects of current rapidly increasing CO2 levels.