Researchers from the University of Granada (UGR) have compared the disaster caused by the Aznalcllar spillage in the Doana National Park in Andalusia 11 years ago with the biggest species extinction known to date. What do these two disasters have in common? The scientists say that carrying out comparisons of this kind will make it possible to find out how ecosystems recover following mass extinctions.
Until now, scientists used to study the fossil record in order to analyse how organisms responded to major environmental changes in the past, such as the mass extinction of species during the Cretaceous period (65 million years ago) and their subsequent recovery.
Now a team of scientists from the UGR has proposed a different methodology: "Another way of looking at this issue is to compare present day disasters that have also caused an abrupt ecological change, and which have therefore also had a major impact on organisms", Francisco Javier Rodrguez-Tovar, lead author of the study and a researcher at the UGR's Department of Stratigraphy and Palaeontology, tells SINC.
The study, published recently in the journal Geobiology, was based on "one of the worst environmental disasters to have happened in Spain over recent decades".
The pyrite mine at Aznalcllar, in the Doana National Park, burst on 25 April 1988, spilling four million cubic metres of acidic water and one million cubic metres of waste material containing high levels of toxic compounds, which affected more than 4,500 hectares of the rivers Agrio and Guadiamar and the land around them.
The researchers carried out a detailed analysis of how the pollution from Aznalcllar evolved, and how the local plant and animal communities responded following the event, by studying the affected soil. "Comparing this with what happened 65 million years ago could help to better interpret this past event", explains Rodrguez-Tovar.
The similarities are obvious s
FECYT - Spanish Foundation for Science and Technology