Life in the world's oceans faces far greater change and risk of large-scale extinctions than at any previous time in human history, a team of the world's leading marine scientists has warned.
The researchers from Australia, the US, Canada, Germany, Panama, Norway and the UK have compared events which drove massive extinctions of sea life in the past with what is observed to be taking place in the seas and oceans globally today.
Three of the five largest extinctions of the past 500 million years were associated with global warming and acidification of the oceans trends which also apply today, the scientists say in a new article in the journal Trends in Ecology and Evolution.
Other extinctions were driven by loss of oxygen from seawaters, pollution, habitat loss and pressure from human hunting and fishing or a combination of these factors.
"Currently, the Earth is again in a period of increased extinctions and extinction risks, this time mainly caused by human factors," the scientists stated. While the data is harder to collect at sea than on land, the evidence points strongly to similar pressures now being felt by sea life as for land animals and plants.
The researchers conducted an extensive search of the historical and fossil records to establish the main causes of previous marine extinctions and the risk of their recurring today.
"We wanted to understand what had driven past extinctions of sea life and see how much of those conditions prevailed today," says co-author Professor John Pandolfi, of the ARC Centre of Excellence for Coral Reef Studies and The University of Queensland, an authority on the fate of coral reefs in previous mass extinction events.
"It is very useful to look back in time because if you forget your history, you're liable to repeat it."
Marine extinction events vary greatly. In the 'Great Death' of the Permian 250 million years ago, for example, an estimate
|Contact: John Pandolfi|
ARC Centre of Excellence in Coral Reef Studies